FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)

WIRELESS COMMUNICATION SYSTEM, TERMINAL APPARATUS, BASE STATION
APPARATUS, AND WIRELESS
COMMUNICATION METHOD”

PANASONIC CORPORATION of 1006, Oaza
Kadoma, Kadoma-shi, Osaka 571-8501, Japan.

The following specification particularly describes the invention and the manner in which it is to be performed.

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Description

WIRELESS COMMUNICATION SYSTEM, TERMINAL APPARATUS, BASE
STATION APPARATUS, AND WIRELESS COMMUNICATION METHOD

Technical Field
[0001]
The present invention relates to a wireless
communication system in which a base station apparatus
and a terminal apparatus can communicate with each other using multiple frequencies.

Background Art
[0002]
The standardization body 3GPP (The 3rd Generation
Partnership Project) promotes standardization of LTE
(Long Term Evolution) as the next generation
communication standard of W-CDMA (Wideband Code Division Multiple Access) system (for example, see Non Patent
Literatures 1 to 3).
[0003]
In this LTE, a base station (E-UTRAN NodeB; also
referred to as eNB) of a network (E-UTRAN: Evolved
Universal Mobile Radio Access Network) has multiple
communication cells (also referred to as cells), and a
terminal (user equipment; hereinafter also referred to as
a UE) belongs to one of the cells. There are two states

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of the terminal: a state called an idle state (RRC_Idle)
in which a radio bearer is not established between the
terminal and the base station and a state called a
connected state (RRC_Connected) in which a radio bearer
is established between the terminal and the base station.
When transmitting/receiving data, the terminal is
required to transit from the idle state to the connected
state.
[0004]
Figure 15 is a sequence diagram for illustrating
transition from the idle state of a terminal to the
connected state. The terminal uses random access means
(random access channel procedure; hereinafter also
referred to as an RACH procedure) to synchronize with the
base station. As shown in Figure 15, the terminal sends
an RACH to the base station, and the base station sends
an RACH response message (RACH response) to the terminal
as a response to the RACH. Through the above operation,
the terminal can synchronize with the base station and
can use a signaling radio bearer 0 (hereinafter also
referred to as an SRB0) for transmitting/receiving a
radio resource control message (hereinafter also referred
to as an RRC message) using a common control channel
(hereinafter also referred to as a CCCH).
[0005]
The terminal sends an RRC connection request to the
base station to establish an RRC connection, using the

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SRB0. The base station transmits an RRC connection setup
to the terminal using the SRB0 in order to establish a
signaling radio bearer 1 (hereinafter referred to as an
SRB1) for transmitting/receiving an RRC message and a
non-access stratum message (hereinafter also referred to
as an NAS message) using a dedicated control channel
(hereinafter also referred to as a DCCH). When receiving
the RRC connection setup, the terminal establishes the
SRB1.
[0006]
Next, the terminal sends an RRC connection setup
complete to the base station using the SRB1 to confirm
that establishment of an RRC connection has succeeded and
has been completed. The base station sends a security
mode command using the SRB1 to enable AS security (access
stratum security) using the SRB1. After that, when a
security mode complete sent from the terminal is received,
AS security is enabled between the terminal and the base
station.
[0007]
At this time, the base station establishes a
signaling radio bearer 2 (hereinafter also referred to as
an SRB2) for transmitting/receiving an NAS message with a
lower priority than the SRB1 in order to prioritize
transmission of an RRC message with a higher urgency (for
example, a handover command and a measurement report)
over an NAS message with a lower urgency (for example,

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addition of a service). When the base station transmits
an RRC connection reconfiguration to the terminal, and
the terminal receives the RRC connection reconfiguration,
the SRB2 is established. The terminal transmits an RRC
connection reconfiguration complete to the base station
using the SRB1 in order to confirm that RRC connection
reconfiguration has succeeded and has been completed.
[0008]
This RRC connection reconfiguration includes
configuration information about a data radio bearer
(hereinafter also referred to as a DRB) for
transmitting/receiving data between the terminal and the
base station, and the terminal establishes the DRB based
on the RRC connection reconfiguration. In this way, the
terminal can transit to the connected state.
[0009]
When the terminal in the connected state moves out
of a cell, a technique called handover (hereinafter also
referred to as HO) is used in which the terminal switches
communication with its own cell to communication with
another cell to avoid disconnection of the communication.
Figure 16 is a sequence diagram showing an example of
handover. As shown in Figure 16, the terminal measures
received power or received quality on the basis of
configuration of measurement of a received signal
included in the RRC connection reconfiguration described
above. When an event (for example, the received power

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exceeding a set threshold) causing a measurement report
to be sent occurs, the terminal sends a measurement
result to a connected base station (hereinafter also
referred to as a source eNB) as a measurement report.
The source eNB decides a base station to be a handover
destination of the terminal (hereinafter also referred to
as a target eNB) on the basis of the measurement report,
and sends a handover request to the target eNB in order
to communicate a request for handover and information
required for handover, to the target eNB.
[0010]
When receiving the handover request, the target eNB
sets a handover command which includes measurement
configuration, mobility control information, radio
resource configuration, security configuration and the
like, and sends the handover command to the source eNB as
a handover request ACK. When receiving the handover
command from the target eNB, the source eNB sends the
handover command to the UE without change. At this time,
the source eNB sends a DL allocation to the UE. The
source eNB transfers the sequence number (hereinafter
also referred to as the SN) of a data packet to be sent
to the UE earliest, among the SNs of data packets which
have not been sent to the UE yet, to the target eNB and
transfers data to be sent to the UE also, to the target
eNB.
[0011]

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The UE synchronizes with the target eNB using the
RACH procedure, sends a handover confirmation to the
target eNB, and completes handover. In this way, the UE
in the connected state can switch communication from a
base station which the UE is communicating with, to
another base station without disconnection of the
communication.
[0012]
The measurement configuration for causing the
terminal to measure received power or received quality
includes information such as measurement identities
(MeasID) which are identities indicating measurement, a
measurement object (MeasObject) indicating a measurement
target, quantity configuration (QuantityConfig)
indicating a measurement result filtering processing
operation and the like, reporting configuration
(ReportConfig) indicating the configuration of a
measurement report, quantity configuration indicating the
configuration of values of the measurement result, and a
measurement gap indicating a period during which data for
measuring other frequencies or other systems is neither
transmitted nor received. This measurement configuration
is included in RRC connection reconfiguration and sent to
the UE from the eNB. Among the above, MeasID, MeasObject
and ReportConfig perform operations in cooperation with
one another. Figure 17 is a diagram showing an example
of the measurement configuration.

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[0013]
As shown in Figure 17, MeasID is an identity
indicating measurement and identifies a measurement
configured by combination of MeasObjectID which is an
identity indicating MeasObject and ReportConfigID which
is an identity indicating ReportConfig. Figure 18 is a
diagram showing an example of MeasObject. As shown in
Figure 18, MeasObject is constituted by a carrier
frequency, the bandwidth of measurement, a frequency
offset, a list of neighbor cells, a blacklist, a report
CGI (cell global identity) and the like. ReportConfig is
constituted by the kind of the trigger for a measurement
report, a trigger quantity, a report quantity, the
maximum number of cells to be reported, a report cycle,
the amount of report (reportAmount) and the like.
[0014]
The ways of sending a measurement report includes:
sending a measurement report at the time of occurrence of
an event (event trigger reporting), sending it
periodically (periodic reporting), and sending it
periodically after occurrence of an event (event trigger
periodic reporting). There are five kinds of E-UTRAN
events, for example, an event of a serving cell being
above a threshold, an event of a serving cell being below
a threshold, an event of a neighbor cell being better
than a servicing cell, an event of a neighbor cell being
better than a threshold, and an event of a servicing cell

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being worse than a threshold 1 and a neighbor cell being better than a threshold 2, and the like.
[0015]
Figure 19 is a diagram showing an example of the
measurement report. In the example of the measurement
report shown in Figure 19, information of MeasID,
reference signal received power (hereinafter also
referred to as RSRP) of a serving cell, and reference
signal received quality (hereinafter also referred to as
RSRQ) of the serving cell is included in the top part,
and the next part includes neighbor cell information.
The neighbor cell information includes information of a
physical cell identity (hereinafter also referred to as a
PCI). Furthermore, information of a global cell identity
(hereinafter also referred to as a CGI), a tracking area
code and a PLMN identity list (public land mobile network
identity list; hereinafter also referred to as a PLMN
list) is optionally included. This neighbor cell
information optionally includes RSRP and RSRQ information.
If there are multiple neighbor cells, multiple pieces of
neighbor cell information are included. For example,
after the first neighbor cell information, the next
neighbor cell information is included as shown in Figure
19. The terminal performs measurement indicated by
MeasID and sends a measurement report to the base station.
The base station decidees whether or not to perform
handover on the basis of the measurement report (and, if

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handover is to be performed, to which cell the handover
is to be performed), and, if handover is to be performed, starts a procedure therefore.
[0016]
Recently, the standardization body 3GPP has promoted
standardization of LTE-A (LTE-Advanced) as a next
generation radio communication standard compatible with
LTE. For LTE-A, introduction of band aggregation (also
referred to as carrier aggregation) in which a terminal
uses multiple carrier frequencies of one base station is
examined. Figure 20 is a diagram showing the outline of
band aggregation. In Figure 20, an example is shown in
which a terminal uses, for example, two component
carriers the carrier frequencies of which are f1 and f2,
among three component carriers (the carrier frequencies
of which are f1, f2 and f3). By using multiple component
carriers as described above, improvement of throughput of
communication between a terminal and a base station is
expected.
[0017]
However, in the existing method described above,
occurrence of an event causing transmission of a
measurement report is determined by comparison with a
terminal's own cell. Therefore, if multiple frequencies
(for example, the two frequencies f1 and f2) are used in
band aggregation, the case is just like the case where
there are two terminal's own cells. Then, if an event

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causing transmission of a measurement report occurs in
one of the terminal's own cells, the terminal sends a
measurement report to a base station, and the base
station decides handover on the basis of the measurement
report, then appropriate handover is not performed
because the other of the terminal's own cell is not
considered at all.
[0018]
Accordingly, it is conceivable to adopt a method in
which the base station requests the terminal to transmit
a measurement report on the basis of the other of the
terminal's own cells. In this case, operations of
transmitting RRC connection reconfiguration from the base
station and receiving the measurement report of the other
of the terminal's own cells from the terminal are
required before the base station receives the measurement
report of the other of the terminal's own cells, and
therefore, it takes prolonged time to perform handover
(contrary to the demand for shortening time required for
handover as much as possible).

Citation List
Non Patent Literature
[0019]
Non Patent Literature 1: 3GPP TS36.331 v8.4.0 "Evolved Universal Terrestrial Radio Access (E-UTRA) Radio
Resource Control (RRC)"

- 11 -
Non Patent Literature 2: 3GPP TS36.300 v8.7.0 "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2"
Non Patent Literature 3: 3GPP TS25.331 v8.5.0 "Radio Resource Control (RRC); Protocol specification"

Summary of Invention
Technical Problem
[0020]
The present invention has been made under the
background described above. The object of the present
invention is to provide a wireless communication system
in which a base station apparatus and a terminal
apparatus can communicate with each other using multiple
frequencies, the wireless communication system being
capable of shortening time required for handover of the
terminal apparatus.

Solution to Problem
[0021]
One aspect of the present invention is a terminal
apparatus used in a wireless communication system in
which a base station apparatus and the terminal apparatus
are communicable with each other using multiple
frequencies; and this terminal apparatus is provided
with: an event detecting section that detects occurrence

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of an event for transmitting a measurement report of a
radio condition of a cell at a frequency set for the base
station apparatus, to the base station communicating with
the terminal apparatus; and a measurement report creating
section that creates the measurement report including
information indicating radio conditions of the cells at a
frequency at which the event occurred and at other
different frequency, on the basis of occurrence of the
event; and the base station apparatus controls whether or
not to perform handover to the cell of the terminal
apparatus on the basis of the measurement report
transmitted from the terminal apparatus.
[0022]
Another aspect of the present invention is a
wireless communication system in which a base station
apparatus and the terminal apparatus are communicable
with each other using multiple frequencies; and the
terminal apparatus is provided with: an event detecting
section that detects occurrence of an event for
transmitting a measurement report of a radio condition of
a cell at a frequency set for the base station apparatus,
to the base station communicating with the terminal
apparatus; and a measurement report creating section that
creates the measurement report including information
indicating radio conditions of the cells at a frequency
at which the event occurred and at another different
frequency, on the basis of occurrence of the event; and

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the base station apparatus is provided with: a handover control section that controls whether or not to perform handover to the cell of the terminal apparatus on the basis of the measurement report transmitted from the
terminal apparatus.
[0023]
Another aspect of the present invention is a base
station apparatus used in a wireless communication system
in which the base station apparatus and a terminal
apparatus are communicable with each other using multiple
frequencies; the terminal apparatus creating the
measurement report including information indicating radio
conditions of cells at a frequency at which the event
occurred and at another different frequency, on the basis
of occurrence of an event for transmitting a measurement
report of a radio condition of a cell at a frequency set
for the base station apparatus, to the base station
communicating with the terminal apparatus; and the base
station apparatus being provided with a handover control
section that controls whether or not to perform handover
to the cell of the terminal apparatus on the basis of the
measurement report transmitted from the terminal
apparatus.
[0024]
Another aspect of the present invention is a
wireless communication method used in a wireless
communication system in which a base station apparatus

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and the terminal apparatus are communicable with each
other using multiple frequencies; and this method
includes: the terminal apparatus detecting occurrence of
an event for transmitting a measurement report of a radio
condition of a cell at a frequency set for the base
station apparatus, to the base station communicating with
the terminal apparatus; and the terminal apparatus
creating the measurement report including information
indicating radio conditions of the cells at a frequency
at which the event occurred and at another different
frequency, on the basis of occurrence of the event; and
the base station apparatus controlling whether or not to
perform handover to the cell of the terminal apparatus on
the basis of the measurement report transmitted from the
terminal apparatus.
[0025]
As described below, other aspects exist in the
present invention. Therefore, this disclosure of the
invention intends to provide a part of aspects of the
present invention and does not intend to limit the scope of the invention described and claimed here.

Brief Description of Drawings
[0026]
[Figure 1] Figure 1 is a diagram showing an example of the positional relationship between a base station

- 15 -
apparatus and a terminal apparatus in a wireless communication system.
[Figure 2] Figure 2 is a block diagram for illustrating the configuration of a terminal apparatus of a first
embodiment.
[Figure 3] Figure 3 is a block diagram for illustrating the configuration of a base station apparatus of the first embodiment.
[Figure 4] Figure 4 is a flowchart showing the flow of handover control in the first embodiment.
[Figure 5] Figure 5 is a flowchart showing an example of the operation of a control section of the terminal
apparatus in the first embodiment.
[Figure 6] Figure 6 is a diagram showing an example of a measurement report which includes frequency information about cells.
[Figure 7] Figure 7 is a flowchart showing an example of the operation of a measurement result reducing section in the first embodiment.
[Figure 8] Figure 8 is a flowchart showing an example of the operation of a control section of a terminal
apparatus in a second embodiment.
[Figure 9] Figure 9 is a diagram showing an example of a
measurement report in which cell quality is indicated by
RSRP.

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[Figure 10] Figure 10 is a diagram showing an example of
a measurement report in which cell quality is indicated
by RSRQ.
[Figure 11] Figure 11 is a flowchart showing the
operation of a measurement result reducing section in a third embodiment.
[Figure 12] Figure 12 is a flowchart showing the
operation of a measurement result reducing section in a fourth embodiment.
[Figure 13] Figure 13 is a flowchart showing the
operation of a measurement result reducing section in a fifth embodiment.
[Figure 14] Figure 14 is a flowchart showing the flow of transmission of a measurement report in another
embodiment.
[Figure 15] Figure 15 is a sequence diagram for
illustrating transition from an idle state of a terminal to a connected state.
[Figure 16] Figure 16 is a sequence diagram showing an example of handover.
[Figure 17] Figure 17 is a diagram showing an example of measurement configuration.
[Figure 18] Figure 18 is a diagram showing an example of MeasObject.
[Figure 19] Figure 19 is a diagram showing an example of a measurement report.

- 17 -
[Figure 20] Figure 20 is a diagram showing the outline of band aggregation.
[Figure 21] Figure 21 is a diagram showing an example of measurement configuration in a sixth embodiment.
[Figure 22] Figure 22 is a diagram showing another
example of measurement configuration.
[Figure 23] Figure 23 is an illustrative diagram of a
cell selection method in an eleventh embodiment.
[Figure 24] Figure 24 is a diagram showing an example of
a measurement report format in a twelfth embodiment.
[Figure 25] Figure 25 is a diagram showing another
example of the measurement report format.
[Figure 26] Figure 26 is a diagram showing another
example of the measurement report format.
[Figure 27] Figure 27 is a diagram showing another
example of the measurement report format.
[Figure 28] Figure 28 is a diagram showing another
example of the measurement report format.

Description of Embodiments
[0027]
Detailed description of the present invention will be shown below. However, the detailed description below and accompanying drawings are not intended to limit the invention. Instead, the scope of the invention is
specified by the accompanying claims.
[0028]

- 18 -

The wireless communication system of the present
invention is a wireless communication system in which a
base station apparatus and a terminal apparatus can
communicate with each other using multiple frequencies,
which is configured so that the terminal apparatus is
provided with: an event detecting section that detects
occurrence of an event for transmitting a measurement
report of a radio condition of a cell at a frequency set
for the base station apparatus, to the base station
communicating with the terminal apparatus; and a
measurement report creating section that creates the
measurement report including information indicating radio
conditions of the cells at a frequency at which the event
occurred and at another different frequency, on the basis
of occurrence of the event; and the base station
apparatus is provided with a handover control section
that controls whether or not to perform handover to the
cell of the terminal apparatus on the basis of the
measurement report transmitted from the terminal
apparatus.
[0029]
Due to this configuration, when an event occurs at a
frequency set for the terminal apparatus by the base
station apparatus, a measurement report including
information indicating radio conditions of cells at a
frequency at which the event occurred and at another
different frequency is transmitted from the terminal

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apparatus to the base station, and it is controlled
whether or not to perform handover of the terminal
apparatus on the basis of the measurement report. Thus,
even in the wireless communication system in which the
base station apparatus and the terminal apparatus are
communicable with each other using multiple frequencies,
the base station can quickly decide whether or not to
perform handover of the terminal apparatus on the basis
of only the measurement report. Thereby, in the wireless
communication system in which the base station apparatus
and the terminal apparatus are communicable with each
other using multiple frequencies, time required for
handover is shortened.
[0030]
The terminal apparatus of the present invention is a
terminal apparatus used in a wireless communication
system in which a base station apparatus and the terminal
apparatus are communicable with each other using multiple
frequencies, the terminal apparatus being provided with:
an event detecting section that detects occurrence of an
event for transmitting a measurement report of a radio
condition of a cell at a frequency set for the base
station apparatus, to the base station communicating with
the terminal apparatus; and a measurement report creating
section that creates the measurement report including
information indicating radio conditions of the cells at a
frequency at which the event occurred and at another

- 20 -

different frequency, on the basis of occurrence of the
event; and the base station apparatus is configured to
control whether or not to perform handover to the cell of
the terminal apparatus on the basis of the measurement
report transmitted from the terminal apparatus.
[0031]
Due to this configuration also, it is possible, even
in the wireless communication system in which the base
station apparatus and the terminal apparatus are
communicable with each other using multiple frequencies,
for the base station apparatus to quickly decide whether
or not to perform handover of the terminal apparatus on
the basis of only the measurement report, similarly to
the above description. Thereby, in the wireless
communication system in which the base station apparatus
and the terminal apparatus are communicable with each
other using multiple frequencies, time required for
handover is shortened.
[0032]
The base station apparatus of the present invention
is a base station apparatus used in a wireless
communication system in which the base station apparatus
and a terminal apparatus are communicable with each other
using multiple frequencies; the terminal apparatus
creating the measurement report including information
indicating radio conditions of cells at a frequency at
which the event occurred and at another different

- 21 -

frequency, on the basis of occurrence of an event for
transmitting a measurement report of a radio condition of
a cell at a frequency set for the base station apparatus,
to the base station communicating with the terminal
apparatus; and the base station apparatus is configured
to have a handover control section that controls whether
or not to perform handover to the cell of the terminal
apparatus on the basis of the measurement report
transmitted from the terminal apparatus.
[0033]
Due to this configuration also, even in the wireless communication system in which the base station and the
terminal apparatus are communicable with each other using multiple frequencies, the base station can quickly decide whether or not to perform handover of the terminal
apparatus on the basis of only the measurement report,
similarly to the above description. Thereby, time
required for handover is shortened in the wireless
communication system in which the base station apparatus
and the terminal apparatus are communicable with each
other using multiple frequencies.
[0034]
The wireless communication method of the present
invention is a wireless communication method used in a
wireless communication system in which a base station
apparatus and the terminal apparatus are communicable
with each other using multiple frequencies, and the

- 22 -

method includes: the terminal apparatus detecting
occurrence of an event for transmitting a measurement
report of a radio condition of a cell at a frequency set
for the base station apparatus, to the base station
communicating with the terminal apparatus; and the
terminal apparatus creating the measurement report
including information indicating radio conditions of the
cells at a frequency at which the event occurred and at
another different frequency, on the basis of occurrence
of the event; and the base station apparatus controlling
whether or not to perform handover to the cell of the
terminal apparatus on the basis of the measurement report
transmitted from the terminal apparatus.
[0035]
According to this method also, it is possible, even
in the wireless communication system in which the base
station apparatus and the terminal apparatus are
communicable with each other using multiple frequencies,
for the base station apparatus to quickly decide whether
or not to perform handover of the terminal apparatus on
the basis of only the measurement report, similarly to
the above description. Thereby, in the wireless
communication system in which the base station apparatus
and the terminal apparatus are communicable with each
other using multiple frequencies, time required for
handover is shortened.
[0036]

- 23 -
The present invention makes it possible to shorten
time required for handover in a wireless communication
system in which a base station apparatus and a terminal
apparatus are communicable with each other using multiple
frequencies, by providing a measurement report creating
section that creates a measurement report including
information indicating radio conditions of cells at a
frequency being used for communication with the base
station and at another different frequency, for the
terminal apparatus.
[0037]
The wireless communication system of embodiments of
the present invention will be described below with the
use of drawings. In the embodiments below, the case of a
wireless communication system using Long Term Evolution
(LTE), System Architecture Evolution (SAE) or the like,
which are mobile communication techniques standardized by
3GPP, will be described as an example. However, the
scope of the present invention is not limited thereto.
That is, the present invention can be applied to wireless
systems using wireless access techniques such as a
wireless LAN (wireless local area network), WiMAX
(Worldwide Interoperability for Microwave Access) such as
IEEE802.16, IEEE802.16e and IEEE802.16m, 3GPP2, and a
fourth generation mobile communication technique.
[0038]

- 24 -
In the embodiments below, description will be made
on a wireless communication system in which a base
station apparatus (also referred to simply as a base
station) and a terminal apparatus (also referred to
simply as a terminal) can communicate with each other
using multiple frequencies (for example, two frequencies
f1 and f2) as an example. In this case, multiple
communication cells are configured at the multiple
frequencies by one base station apparatus.
[0039]
Figure 1 is a diagram showing an example of the
positional relationship between a base station apparatus
and a terminal apparatus in the wireless communication
system of the embodiments of the present invention. As
shown in Figure 1, a wireless communication system 1 is
constituted by terminal apparatuses 2 (UEs), such as a
mobile telephone and a mobile terminal, and a base
station apparatus 3 (eNB) which communicates with the
terminal apparatuses 2. The base station 3 manages
multiple cells at multiple frequencies (for example,
three communication cells corresponding to the frequency
f1 and communication cells corresponding to f2), and the
terminal apparatuses 2 can use the component carriers of
the multiple cells at the same time. To use the multiple
component carriers at the same time is referred to as
band aggregation. In the embodiments below, description
will be made on the case of using two component carriers

- 25 -
(the carrier frequencies f1 and f2) as an example of the
band aggregation. However, the scope of the present
invention is not limited thereto. For example, three or
more component carriers may be used. The terminal
apparatus 2 existing in a communication cell of the base
station 3 may not only use the two component carriers by
performing band aggregation but also use only one
component carrier as the case may be (according to
circumstances).
[0040]
(First embodiment)
The configuration of a wireless communication system 1 of a first embodiment will be described with reference to Figures 2 and 3. Figure 2 is a block diagram for
illustrating the configuration of the terminal apparatus 2 of this embodiment, and Figure 3 is a block diagram for illustrating the configuration of the base station
apparatus 3 of this embodiment.
[0041]
In the wireless communication system 1 of this
embodiment, the terminal apparatus 2 is provided with a
function of receiving a reference signal transmitted from
the base station 3 or another base station 3 via a
downlink and reporting a measurement result of the
received signal to the base station 3 via an uplink. The
base station 3 is provided with a function of assigning
and controlling wireless resources (for example,

- 26 -

frequency bands in frequency domains and time domains)
and performing handover processing in the case of judging that handover to another cell 3 is necessary from the
reference signal measurement result reported from the
terminal apparatus 2. The base station 3 can be said to play the role of an access point of a wireless access
network for the terminal apparatus 2.
[0042]
(Terminal apparatus)
First, the configuration of the terminal apparatus 2
of this embodiment will be described with reference to
Figure 2. As shown in Figure 2, the terminal apparatus 2
is provided with a reception section 4, a measurement
information managing section 5, a control section 6, a
measurement report creating section 7 and a transmission
section 8.
[0043]
The reception section 4 is provided with a function
of receiving system information and the like transmitted
from the base station 3 or another base station 3, in
response to an indication sent from the control section 6.
The reception section 4 is also provided with a function
of receiving a reference signal transmitted from the base
station 3 or another base station 3, in response to an
indication sent from the measurement information managing
section 5. The reception section 4 is configured to
output the control information such as the system

- 27 -

information to the control section 6 and output the
reference signal to the measurement information managing section 5.
[0044]
The measurement information managing section 5 is
provided with a function of individually managing
indications from the control section 6, such as
measurement result output indications inputted from the
control section 6 (for example, an indication to
periodically output a measurement result, an indication
to output a measurement result at the time of occurrence
of an event, an indication to periodically output a
measurement result after occurrence of an event, an
indication to output a measurement result of a particular
frequency and an indication to output a measurement
result of a particular cell). The measurement
information managing section outputs a reference signal
reception indication to the reception section 4 in
response to an indication from the control section 6.
The measurement information managing section 5 is
configured to, in the case where an indication from the
control section 6 is applicable, output a measurement
result corresponding to the indication to the control
section 6. This measurement information managing section
5 is provided with a function of detecting occurrence of
an event, and it corresponds to event detecting means of
the present invention.

- 28 -

[0045]
The control section 6 is provided with a function of
performing measurement configuration on the basis of
control information sent from the reception section 4 or
control information incorporated in advance. This
control section 6 is provided with a function of
instructing the measurement information managing section
5 to output a measurement result, on the basis of the
measurement configuration. The control section 6 is also
provided with a function of judging whether to create a
measurement report on the basis of only a measurement
result of the carrier frequency of one component carrier
or to create the measurement report by adding a
measurement result of one carrier frequency to a
measurement result of the carrier frequency of the other
component carrier. That is, this control section 6
corresponds to judgment means of the present invention.
[0046]
The measurement report creating section 7 is
provided with a function of creating a measurement report
from information inputted from the control section 6.
This measurement report creating section 7 is provided
with a measurement result reducing section 9 that selects
a cell to be included into a measurement report from a
measurement result inputted from the control section 6.
The measurement report creating section 7 is configured
to create a measurement report on the basis of a

- 29 -
measurement result of a cell selected by this measurement
result reducing section 9 and send the created
measurement report to the transmission section 8. Here,
this measurement report creating section 7 corresponds to
measurement report creating means of the present
invention. The transmission section 8 is provided with a
function of transmitting inputted information to the base
station 3.
[0047]
(Base station apparatus)
Next, the configuration of the base station 3 of
this embodiment will be described with reference to
Figure 3. As shown in Figure 3, the base station 3 is
provided with a reception section 10, a measurement
information managing section 11, a handover judgment
processing section 12, a control section 13 and a
transmission section 14. The handover judgment
processing section 12 is provided with a judgment
processing section for band-aggregation 15 and a normal judgment processing section 16.
[0048]
The reception section 10 is provided with a function of outputting a measurement report received from the
terminal apparatus 2 to the measurement information
managing section 11.
[0049]

- 30 -
The measurement information managing section 11 is
configured to, when notified from the control section 13 that the terminal apparatus 2 is using band aggregation, output a measurement report to the judgment processing
section for band-aggregation 15. The measurement
information managing section 11 is also configured to,
when nothing is notified from the control section 13 or
when notified that the terminal apparatus 2 is using only one component carrier, output a measurement report to the normal judgment processing section 16.
[0050]
The normal judgment processing section 16 of the
handover judgment processing section 12 is provided with
a function of judging whether or not to perform handover
of the terminal apparatus 2 on the basis of a measurement
report inputted from the measurement information managing
section 11 and information inputted from the control
section 13. In comparison, the judgment processing
section for band-aggregation 15 of the handover judgment
processing section 12 is provided with a function of
judging whether or not to perform handover of the
terminal apparatus 2 on the basis of a measurement report
inputted from the measurement information managing
section 11 and information inputted from the control
section 13. This handover judgment processing section 12
corresponds to handover control means of the present
invention.

- 31 -

[0051]
The control section 13 outputs control information
for communicating measurement configuration to the
terminal apparatus 2 or reference signal schedule
information to the transmission section 14. The control
section 13 is provided with a function of, when the
terminal apparatus 2 is performing band aggregation,
notifying the measurement information managing section 11
that the terminal apparatus 2 is performing band
aggregation. When the terminal apparatus 2 is using only
one component carrier, this control section 13 may notify
the measurement information managing section 11 that the
terminal apparatus 2 is using only one component carrier.
The transmission section 14 is provided with a function
of sending a reference signal or control information on
the basis of schedule information.
[0052]
Description will be made on the operation of the
wireless communication system 1 configured as described
above, with reference to drawings. Description will be
made here mainly on handover control, which is a
characteristic operation of the present invention.
[0053]
(Operation of the whole system)
First, the operation of the whole system of the
wireless communication system 1 in the first embodiment
will be described with reference to Figure 4. Figure 4

- 32 -

is a flowchart showing the flow of the operation
performed when handover control is performed in the
wireless communication system 1 of this embodiment.
First, the base station 3 sends control information to
the terminal apparatus 2 (S100), and the terminal
apparatus 2 performs measurement of a reference signal on
the basis of the control information (S101), as shown in
Figure 4. If the result of the measurement satisfies the
criterion for reporting to the base station 3 decided in
the control information (S102), the terminal apparatus 2
judges whether or not the terminal apparatus 2 is
performing band aggregation (S103). If the terminal
apparatus 2 is using only one component carrier (if the
terminal apparatus 2 is not performing band aggregation),
the terminal apparatus 2 sets a measurement report which
is created from the measurement result and transmits it
to the base station 3 (S104). On the other hand, if the
terminal apparatus 2 is performing band aggregation (if
the terminal apparatus 2 is using multiple component
carriers), the terminal apparatus 2 sets a measurement
report for band aggregation which is created from the
measurement result and transmits it to the base station 3 (S105). The base station 3 judges whether or not to
perform handover, from the measurement report sent from the terminal apparatus 2 (S106).
[0054]
(Operation of control section of terminal apparatus)

- 33 -
Next, the operation of the control section 6 of the
terminal apparatus 2 in the first embodiment will be
described with reference to Figure 5. Figure 5 is a
flowchart showing an example of the operation of the
control section 6 performed when an event causing a
measurement report occurs in the terminal apparatus 2 and
a measurement result is outputted from the measurement
information managing section 5. As shown in Figure 5,
when a measurement result is inputted from the
measurement information managing section 5 (S110), the
control section 6 judges whether or not the terminal
apparatus 2 is performing band aggregation (S111). If
the terminal apparatus 2 is not performing band
aggregation, that is, if the terminal apparatus 2 is
using only one component carrier, the control section 6
outputs the measurement result to the measurement report
creating section 7 (S112).
[0055]
If the terminal apparatus 2 is performing band
aggregation, that is, if the terminal apparatus 2 is
using two component carriers, the control section 6
judges whether to create a measurement report on the
basis of a measurement result of the carrier frequency of
one component carrier or to create the measurement report
by adding a measurement result of the carrier frequency
of one component carrier to the measurement result of the
carrier frequency of the other component carrier (S113).

- 34 -
The judgment criterion to be used then may be sent from
the base station 3 to the terminal apparatus 2, or
judgment criterion included in control information sent
from the base station 3 may be used. Furthermore, the
judgment criterion may be set in the terminal apparatus 2 in advance or may be generated by the terminal apparatus 2 according to circumstance.
[0056]
Here, this judgment (S113) will be described in more
detail by giving a concrete example. For example, in the
case where band aggregation is performed only within one
band, such as in the case where only a 800-MHz band
component carrier is used for band aggregation (or in the
case where only a 2-GHz carrier is used for band
aggregation), it is judged that a measurement report is
to be created on the basis of only a measurement result
of the carrier frequency of one component carrier. On
the other hand, in the case where a 800-MHz band
component carrier and a 2-GHz band component carrier are
used for band aggregation, it is judged that a
measurement report is to be created by adding a
measurement result of one carrier frequency to a
measurement result of the other carrier frequency.
[0057]
In another example, for example, if the component
carriers used for band aggregation have adjacent carrier
frequencies, it is judged that a measurement report is to

- 35 -
be created on the basis of only a measurement result of
the carrier frequency of one component carrier. On the
other hand, if the component carriers used for band
aggregation are not adjacent to each other, it is judged
that a measurement report is to be created by adding a
measurement result of one carrier frequency to a
measurement result of the other carrier frequency.
[0058]
In still another example, for example, if carrier
frequency difference between component carriers used for
band aggregation is equal to or less than x MHz (for
example, x=20), it is judged that a measurement report is
to be created on the basis of only a measurement result
of the carrier frequency of one component carrier. On
the other hand, if the carrier frequency difference
between the component carriers used for band aggregation
is more than x MHz (for example x=20), it is judged that
a measurement report is to be created by adding a
measurement result of one carrier frequency to a
measurement result of the other carrier frequency.
[0059]
In still another example, for example, if a neighbor
cell with a quality equal to or above a criterion is
included when the criterion is smaller than s-measure (a
threshold to be a criterion for starting measurement) in
a measurement result of one carrier frequency by a value
x dB (for example, x=10), then it is judged that a

- 36 -
measurement report is to be created on the basis of only
a measurement result of the carrier frequency of the one
component carrier. If there is not a cell satisfying
this criterion, it is judged that a measurement report is
to be created by adding a measurement result of one
carrier frequency to a measurement result of the other
carrier frequency. The value of x may be a negative
value.
[0060]
In still another example, for example, if a
measurement result of one carrier frequency includes a
neighbor cell having a quality equal to or above a
criterion when the criterion is x dB (for example x=-10),
then it is judged that a measurement report is to be
created on the basis of only a measurement result of the
carrier frequency of the one component carrier. If there
is not a cell satisfying this criterion, it is judged
that a measurement report is to be created by adding a
measurement result of one carrier frequency to a
measurement result of the other carrier frequency.
[0061]
In still another example, for example, if a
measurement result of one carrier frequency includes a
measurement result of a component carrier to which it can
be judged to perform handover (for example, an anchor
carrier or a component carrier having the best received
quality among component carriers used by the terminal),

- 37 -
it is judged that a measurement report is to be created
on the basis of only a measurement result of the carrier
frequency of the one component carrier. If a measurement
result of one carrier frequency does not include a
measurement result of a component carrier to which it can
be judged to perform handover (for example, an anchor
carrier or a component carrier having the best received
quality among component carriers used by the terminal),
it is judged that a measurement report which includes a
measurement result of a component carrier to which it can
be judged to perform handover (for example, an anchor
carrier or a component carrier having the best received
quality among component carriers used by the terminal) is
to be created.
[0062]
If it is judged to set a measurement report which is
created from only the measurement result of the carrier
frequency of one component carrier, as a result of this
judgment (S113), the control section 6 outputs the
measurement result to the measurement report creating
section 7 (S114). On the other hand, if it is judged, as
a result of this judgment (S113), that a measurement
report is to be created by adding the measurement result
of the carrier frequency of one carrier component to the
measurement result of the carrier frequency of the other
component carrier, the control section 6 instructs the

- 38 -
information managing section to output the measurement
result of the other carrier frequency (S115).
[0063]
Here, the judgment criterion of a measurement result
of the other carrier frequency to be included in a
measurement report will be described in more detail by
giving a concrete example. For example, it is assumed
that, when the terminal apparatus 2 is performing band
aggregation using the carrier frequencies f1 and f2, a
trigger (event) for creating a measurement report occurs
at the carrier frequency f1. At this time, some cells
(for example, five cells) are selected from among cells
of the carrier frequencies f1 and f2, in order of quality
with a cell having the best quality at the top,
irrespective of whether the carrier frequency is f1 or f2,
and made to be a measurement result.
[0064]
Because cell identities (physical cell identities
(PCIs)) included in the measurement result then are
assigned within a frequency in a manner that neighbor
cells do not have the same identities, there may be a
case where neighbor cells have the same identities when
the frequency changes. Therefore, at the time of
creating a measurement report, the measurement report
creating section 7 creates the measurement report by
providing separators to indicate which frequency each
cell has.

- 39 -

[0065]
Figure 6 is a diagram showing an example of a
measurement report which includes frequency information
about cells. In the example in Figure 6, after RSRQ
information about a serving cell before putting
information about a neighbor cell, carrier frequency
information about the neighbor cell is put, and the
number of pieces of information about neighbors with the
carrier frequency to be included in the measurement
report is shown. Thereby, the base station 3 can judge
which frequency the cells of the information belong to.
[0066]
In another example, it is possible to determine the
number of cells (for example, two) of the other carrier
frequency to be included into a measurement result in
advance and include the number of cells corresponding to
the number. In still another example, it is also
possible to determine a threshold of the absolute value
or the relative value in advance and include such a cell
with the other carrier frequency that exceeds the
threshold value into a measurement result (for example,
include a cell exceeding -30 dBm, among cells with the
other carrier frequency, into the measurement result).
In still another example, it is also possible to give an
offset to each carrier frequency, select some cells in
order of quality with a cell having the best quality at

- 40 -
the top in consideration of the offset, and include them into a measurement result.
[0067]
In still another example, when the terminal is
performing band aggregation using the carrier frequencies
f1 and f2, an indication to compare the qualities of
cells of f1 and cells of a carrier frequency f3 which is
not used for the band aggregation to make an event
judgment has been given from the base station. In this
case, if the criterion for sending a measurement report
are satisfied as a result of the event judgment, such
cells that satisfy the event criterion at f3, the serving
cells of f1, and y cells (for example, y=1) regarded as
having a good quality at f2 for which event judgment has
not been performed and which is being used for the band
aggregation may be selected and included into a
measurement result.
[0068]
In still another example, it is also possible to, if
the criterion for sending a measurement report is
satisfied at f1 as a result of event judgment when the
terminal is performing band aggregation using the carrier
frequencies f1 and f2, select a component carrier which
the terminal uses and to which it can be judged to
perform handover (for example, an anchor carrier or a
component carrier having the best received quality among
component carriers used by the terminal) and include it

- 41 -
into a measurement result. For example, if the component
carrier from which it can be judged to perform handover
is f2 when an event of setting a serving cell to f1 is
judged at the carrier frequency f1, the received quality
of the component carrier of f2, among the component
carriers used by the terminal, is included into a
measurement report. Thereby, the base station can obtain
information from which it can be judged to perform
handover as early as possible and, therefore, start a
handover procedure early. By including the received
quality of the best component carrier, the base station
can easily judge whether or not the terminal had better
continue using the set of component carriers.
[0069]
In the case where coverage differs among frequencies,
the effect is enhanced if the amount of interference
differs. The terminal may include the received quality
of a component carrier from which it can be judged to
perform handover (for example, an anchor carrier or a
component carrier having the best received quality among
components carriers used by the terminal) into a
measurement report even if nothing is notified from the
base station.
[0070]
The terminal may include the received quality of a
component carrier from which it can be judged to perform
handover (for example, an anchor carrier or a component

- 42 -
carrier having the best received quality among components
carriers used by the terminal) into a measurement report
only when there is a notification from the base station.
[0071]
When a measurement result of the other carrier
frequency is inputted from the measurement information
managing section 5, the control section 6 outputs a
measurement result of the carrier frequency of one
component carrier and the measurement result of the other carrier frequency to the measurement result reducing
section 9. Moreover, at this time, it is possible to
output the information that the measurement result of the other carrier frequency is included, to the measurement result reducing section 9.
[0072]
If information required for reducing a cell in a
measurement result is sent from the base station 3, this
control section 6 inputs the information to the
measurement result reducing section 9 without change.
For example, when a policy for deciding handover or a
policy for deciding s-measure (hereinafter also referred
to simply as a "policy") is sent from the base station 3
as control information, the control section 6 inputs the
policy to the measurement result reducing section 9.
Furthermore, if the base station 3 creates a judgment
criterion from the policy, and the judgment criterion is
sent to the terminal apparatus 2 as control information,

- 43 -
the control section 6 inputs the judgment criterion to
the measurement result reducing section 9.
[0073]
(Operation of measurement result reducing section of terminal apparatus)
Next, the operation of the measurement result
reducing section 9 of the terminal apparatus 2 in the
first embodiment will be described with reference to
Figure 7. Figure 7 is a flowchart showing an example of
the operation of the measurement result reducing section
9. As shown in Figure 7, when a measurement result is
inputted from the control section 6 (S120), the
measurement result reducing section 9 deletes a cell from
the measurement result on the basis of a judgment
criterion created from a policy (S121). As for this
judgment criterion, the judgment criterion itself may be
inputted from the control section 6, or the judgment
criterion itself may be held in the measurement result
reducing section 9 in advance. This judgment criterion
may be generated from a policy inputted from the control
section 6 or may be generated from a policy held in the
measurement result reducing section 9 in advance. The
measurement result reducing section 9 selects a cell to
be included in a measurement report on the basis of such
a judgment criterion.
[0074]

- 44 -
Here, selection of a cell on the basis of a judgment
criterion generated from a policy will be described in
more detail by giving a concrete example. The judgment
criterion generated from a policy is for selecting a cell
with a high probability of being used for handover. For
example, when the carrier frequencies f1 and f2 are used,
and the number of cells with the carrier frequency f1 and
the number of cells with the carrier frequency f2 are
eight and two, respectively, that is, there is a large
difference between the number of cells with the carrier
frequency f1 and the number of cells with the carrier
frequency f2, the number of the cells in a measurement
result is decreased by decreasing the number of cells
with the carrier frequency f1 by three in order of
quality with a worst-quality cell at the top.
Alternatively, for example, five cells are selected from
among the cells with the carrier frequency f1 and the
cells with the carrier frequency f2 in order of quality
with a best-quality cell at the top so that the total of
five cells are included in a measurement result, and the
five cells are included into the measurement result.
[0075]
Then, the measurement result reducing section 9
outputs the measurement result of selection of cells to
the measurement report creating section 7 (S122). A
policy is for limiting a cell to be selected for handover.
Therefore, by the terminal apparatus 2 limiting cells to

- 45 -

be selected, using this policy, it is possible to
decrease unnecessary cells for handover from a
measurement report and reduce the size of the measurement report.
[0076]
According to this wireless communication system 1 of
the first embodiment of the present invention, it is
possible to, by providing the measurement report creating
section 7 which creates a measurement report including
information indicting radio conditions of cells with a
frequency at which an event causing transmission of a
measurement result occurred and cells with a frequency
different from the frequency, for the terminal apparatus
2, shorten time required for handover in the wireless
communication system 1 in which the base station 3 and
the terminal apparatus 2 are communicable with each other.
[0077]
The wireless communication system 1 of this
embodiment is the wireless communication system 1 in
which a base station apparatus 3 and a terminal apparatus
2 are communicable with each other using multiple
frequencies; and the system is configured so that the
terminal apparatus 2 is provided with: a measurement
information managing section 5 that detects occurrence of
an event for transmitting a measurement report of a radio
condition of a cell at a frequency set for the base
station apparatus 3, to the base station 3 communicating

- 46 -

with the terminal apparatus; a measurement report
creating section 7 that creates the measurement report
including information indicating radio conditions of the
cells at a frequency at which the event occurred and at
another different frequency, on the basis of occurrence
of the event; and the base station apparatus 3 is
provided with: a handover judgment processing section 12
that controls whether or not to perform handover to
another cell of the terminal apparatus 2 on the basis of
the measurement report transmitted from the terminal
apparatus 2.
[0078]
Due to this configuration, when an event occurs in
the terminal apparatus 2 at a frequency set for the base
station 3, a measurement report including information
indicating radio conditions of cells at the frequency at
which the event occurred and at another different
frequency is transmitted from the terminal apparatus 2 to
the base station 3, and it is controlled whether or not
to perform handover of the terminal apparatus 2 on the
basis of the measurement report. Thus, even in the
wireless communication system 1 in which the base station
apparatus 3 and the terminal apparatus 2 are communicable
with each other using multiple frequencies, the base
station 3 can quickly decide whether or not to perform
handover of the terminal apparatus 2 on the basis of only
the measurement report. Thereby, in the wireless

- 47 -

communication system 1 in which the base station
apparatus 3 and the terminal apparatus 2 are communicable with each other using multiple frequencies, time required for handover is shortened.
[0079]
In the wireless communication system 1 of this
embodiment, the measurement report creating section 7 is
configured to select a part of a measurement report of
the radio conditions of cells at a frequency at which an
event occurred and a part of a measurement report of the
radio conditions of cells at another frequency, as
information indicating the radio conditions of the cells
at the frequency at which the even occurred and
information indicating the radio conditions of the cells
at that another frequency.
[0080]
Due to this configuration, a part of a measurement
report of the radio conditions of cells at a frequency at
which an event occurred and a part of a measurement
report of the radio conditions of cells at another
frequency are selected as information indicating the
radio conditions of the cells at the frequency at which
the event occurred and information indicating the radio
conditions of the cells at that another frequency.
Therefore, in comparison with the case of including all
the measurement reports of the radio conditions of the
cells at the frequency at which the event occurred and

- 48 -
the cells at that another frequency, the data size of the
measurement report to be transmitted from the terminal
apparatus 2 to the base station 3 can be reduced, and it
becomes possible to reduce the amount of traffic.
[0081]
It is also conceivable to introduce additional
measurement identities which have been conventionally
used in a UMTS (universal mobile telecommunication
system) to include a measurement result of another
frequency into a measurement report. In the UMTS, there
is a setting item of "additional measurement identities"
at the time of performing measurement configuration. The
"additional measurement identities" indicates a reference
list of other measurements. When a measurement report
for the measurement is sent, the reporting quantity
(measurement result) of a referred measurement can be
included. However, if this "additional measurement
identities" is simply introduced, multiple measurement
results for independent measurement configuration are
included in a measurement report. Consequently, the size
of the measurement report increases, and the amount of
traffic increases. In comparison with this method, it is
possible, in the wireless communication system 1 of this
embodiment, to reduce the data size of a measurement
report transmitted from the terminal apparatus 2 to the
base station 3 and reduce the amount of traffic.
[0082]

- 49 -
Furthermore, in the wireless communication system 1
of this embodiment, the terminal apparatus 2 is
configured to be provided with the control section 6
which judges whether or not to create a measurement
report including information indicating the radio
conditions of cells at a frequency at which an event
occurred and cells at another frequency.
[0083]
Due to this configuration, if it is not judged that
a measurement report including information indicating the
radio conditions of cells at a frequency at which an
event occurred and cells at another frequency should be
created, only a measurement report of the radio
conditions of the cells at the frequency at which the
event occurred is transmitted to the base station 3.
Thereby, if it is judged that information indicating the
radio conditions of cells at another frequency is
unnecessary, only necessary information is transmitted.
Thus, it is possible to reduce the data size of a
measurement report transmitted from the terminal
apparatus 2 to the base station 3 and reduce the amount
of traffic.
[0084]
Furthermore, in the wireless communication system 1
of this system, a policy for deciding a cell selected as
a candidate for performing handover, among other multiple
cells, is set in the terminal apparatus 2, and the

- 50 -
measurement report creating section 7 is configured to
select a measurement report of a cell selected as the
candidate on the basis of the policy among measurement
reports of the other multiple cells, as information
indicating the wave radio conditions of cells at a
frequency at which an event occurred and at another
frequency.
[0085]
Due to this configuration, a measurement report of a
cell selected as a candidate for performing handover,
among other multiple cells, on the basis of a handover
policy set in the terminal apparatus 2 is selected as
information indicating the radio conditions of other
multiple cells. Therefore, in comparison with the case
of including all the measurement reports of the radio
conditions of the other multiple cells, the data size of
the measurement report to be transmitted from the
terminal apparatus 2 to the base station 3 can be reduced,
and it becomes possible to reduce the amount of traffic.
The policy may be set in the terminal apparatus 2 in
advance or may be received from the base station 3 and
set in the terminal apparatus 2.
[0086]
(Second embodiment)
Next, the wireless communication system 1 of a
second embodiment of the present invention will be
described. Here, description will be made mainly on a

- 51 -

point in which the wireless communication system 1 of
this embodiment is different from the first embodiment. Therefore, the configuration and operation of this
embodiment are similar to those of the first embodiment unless otherwise especially referred to.
[0087]
In this embodiment, the operation of the control
section 6 performed when an event causing a measurement
report occurs in the terminal apparatus 2 and a
measurement result is outputted from the measurement
information managing section 5 is different from that of
the first embodiment. Therefore, the operation of the
control section 6 of the terminal apparatus 2 in the
second embodiment will be described here with reference
to drawings.
[0088]
Figure 8 is a flowchart showing an example of the
operation of the control section 6 performed when an
event causing a measurement report occurs in the terminal
apparatus 2 and a measurement result is outputted from
the measurement information managing section 5. As shown
in Figure 8, when a measurement result is inputted from
the measurement information managing section 5 (S200),
the control section 6 judges whether or not the terminal
apparatus 2 is performing band aggregation (S201). If
the terminal apparatus 2 is not performing band
aggregation, that is, if the terminal apparatus 2 is

- 52 -
using only one component carrier, the control section 6 outputs the measurement result to the measurement report creating section 7 (S202).
[0089]
If the terminal apparatus 2 is performing band
aggregation, that is, if the terminal apparatus 2 is
using two component carriers, the control section 6
judges whether to create a measurement report on the
basis of a measurement result of the carrier frequency of
one component carrier or to create the measurement report
by adding a measurement result of the carrier frequency
of one component carrier to the measurement result of the
carrier frequency of the other component carrier (S203).
The way of judgment and the judgment criterion are
similar to those of the first embodiment. [0090]
The control section 6 performs control so that a
measurement result in which cell quality is indicated by
RSRP is sent to the base station 3 if it is judged that a
measurement report is to be created on the basis of only
a measurement result of the carrier frequency of one
component as a result of this judgment, and a measurement
result in which cell quality is indicated by RSRQ is sent
to the base station 3 if it is judged that a measurement
report is to be created, with a measurement result of the
other carrier frequency included. In this case, it can
be said that the measurement report creating section 7 is

- 53 -
controlled to create a measurement result in which cell
quality is indicated by RSRP if it is judged that a
measurement report is to be created on the basis of only
a measurement result of the carrier frequency of one
component as a result of this judgment and create a
measurement result in which cell quality is indicated by
RSRQ if it is judged that a measurement report is to be
created, with a measurement result of the other carrier
frequency included.
[0091]
Here, concrete examples of a measurement report in
which cell quality is indicated by RSRP and a measurement
report in which cell quality is indicated by RSRP will be
shown with figures. Figure 9 is a diagram showing an
example of the measurement report in which cell quality
is indicated by RSRP. As shown in Figure 9, this
measurement report includes RSRP information indicating
cell quality and does not include RSRQ information.
Figure 10 is a diagram showing an example of the
measurement report in which cell quality is indicated by
RSRQ. As shown in Figure 10, this measurement report
includes RSRQ information indicating cell quality and
does not include RSRP information. Thus, a measurement
report including information indicating cell quality is
created. The base station 3 cannot change the format of
a measurement report so as to make the contents of the
measurement report understandable. However, by causing

- 54 -
information used for indicating cell quality to differ by
using RSRP and RSRQ, the condition at another frequency
can be communicated to the base station 3 (without
changing the measurement report format).
[0092]
If it is judged that a measurement report is to be
created on the basis of only a measurement result of the
carrier frequency of one component carrier, as a result
of the above judgment (S203), the control section 6
confirms whether cell quality is described with RSRP
(S204). If the cell quality is not described with RSRP,
the control section 6 instructs the measurement
information managing section 5 to output a measurement
result in which the cell quality is indicated by RSRP,
and acquires the measurement result in which the cell
quality is described with RSRP (S205). Then, the control
section 6 outputs the measurement result in which the
cell quality is described with RSRP to the measurement
report creating section 7 (S206). On the other hand, if
the cell quality is described with RSRP, the control
section 6 outputs the measurement result to the
measurement report creating section 7 (S206). The
control section 6 may output that it is the measurement
result of the carrier frequency of one component carrier,
to the measurement report creating section 7 then.
[0093]

- 55 -
On the other hand, if it is judged, as a result of
the above judgment (S203), that a measurement result of
the other carrier frequency is to be included into a
measurement report, the control section 6 instructs the
measurement information managing section 5 to output a
measurement result of the carrier frequency of the one
component carrier and a measurement result of the other
carrier frequency as RSRQ and acquires the measurement
results in which cell quality is described with RSRQ
(S207). Then, when the measurement result of each
carrier frequency is inputted from the measurement
information managing section 5, the control section 6
outputs the inputted measurement results to the
measurement result reducing section 9 (S208). The
control section 6 may output that it is the measurement
result of each carrier frequency, to the measurement
result reducing section 9 then.
[0094]
In this embodiment, the operation of the handover
judgment processing section 12 of the base station 3
performed when a measurement report as described above is received from the terminal apparatus 2 is different from that of the first embodiment.
[0095]
If cell quality is described as RSRP in an inputted
measurement report, the judgment processing section for
band-aggregation 15 of the handover judgment processing

- 56 -

section 12 judges whether or not to perform handover
using the same frequencies as the carrier frequencies
used by the terminal apparatus 2 (intra-frequency
handover) to another cell, on the basis of the
measurement result. If the cell quality is described
with RSRQ in the inputted measurement report, the
judgment processing section for band-aggregation 15
judges whether or not to select an appropriate cell from
among cells managed by one base station 3 and perform
handover using the same frequencies as the carrier
frequencies used by the terminal apparatus 2 (intra-
frequency handover) or handover using carrier frequencies
all or a part of which are different from the carrier
frequencies used by the terminal apparatus 2 (inter-
frequency handover) while performing band aggregation.
This judgment processing section for band-aggregation may
judge that the band aggregation should be ended, and
handover should be performed to another base station 3.
[0096]
Operations and advantages similar to those of the
first embodiment can be obtained by the wireless
communication system 1 of the second embodiment.
[0097]
In the wireless communication system 1 of this
embodiment, the measurement report creating section 7 is
configured to create, if handover control should be
performed on the basis of both of measurement reports of

- 57 -

a frequency at which an event occurred and another
frequency, a measurement report including information
about the received quality (RSRQ) of radio waves from
cells with these frequencies, and, if handover control
should be performed on the basis of only the frequency at
which the event occurred, create a measurement report
including information about the received power (RSRP) of
radio waves from cells with that frequency.
[0098]
Due to this configuration, the base station 3
controls handover on the basis of both of measurement
reports of a frequency at which an event occurred in the
terminal apparatus 2 and another frequency if a
measurement report received from the terminal apparatus 2
includes received quality information, and controls
handover on the basis of only the measurement report of
the frequency at which the event occurred in the terminal
apparatus 2 if the measurement report received from the
terminal apparatus 2 includes received power information.
Thereby, on the basis of which of received quality
information and received power is included in a
measurement report, the base station 3 can quickly decide
which frequency measurement report handover of the
terminal apparatus 2 should be controlled on the basis of.
Thereby, in the wireless communication system 1 in which
the base station apparatus 3 and the terminal apparatus 2

- 58 -

are communicable with each other using multiple
frequencies, time required for handover is shortened. [0099]
Thus, in this embodiment, since a measurement report
transmitted from the terminal apparatus 2 includes
information indicating whether a measurement result of
the carrier frequency of one component carrier or a
measurement result of the other carrier frequency is
included, it is easy for the base station 3 to judge
handover.
[0100]
That is, in this embodiment, since the terminal
apparatus 2 can include information required by the base
station 3 for handover, into one measurement report at
the time of performing band aggregation, the base station
3 can decide handover early. In the case where a
measurement report is created from a measurement result
which includes only cells on the basis of the carrier
frequency of one component carrier, the base station 3
can judge handover only from RSRP out of consideration of
interference power. On the other hand, in the case where
a measurement report which includes a measurement result
of another carrier frequency is created, the base station
3 can judge handover from RSRQ in consideration of
interference power.
[0101]

- 59 -

In this case, the number of bits required for
transmission differs between RSRP and RSRQ. A smaller
number of bits is required for RSRQ. Therefore, even in
the case where a measurement report of another carrier
frequency is included in a measurement report, and the
number of cells included in the measurement report is
increased, the size of the measurement report can be
reduced.
[0102]
(Third embodiment)
Next, the wireless communication system 1 of a third
embodiment of the present invention will be described.
Here, description will be made mainly on a point in which
the wireless communication system 1 of this embodiment is
different from the first embodiment. Therefore, the
configuration and operation of this embodiment are
similar to those of the first embodiment unless otherwise
especially referred to.
[0103]
In this embodiment, the operation of the measurement result reducing section 9 performed when a measurement
report is created is different from that of the first
embodiment. Therefore, the operation of the measurement
result reducing section 9 of the terminal apparatus 2 in the third embodiment will be described here with
reference to drawings.
[0104]

- 60 -
Figure 11 is a flowchart showing the operation of
the measurement result reducing section 9 of the third
embodiment. First, a measurement result constituted by
cells using the carrier frequency of each component
carrier is inputted to the measurement result reducing
section 9 (S300), as shown in Figure 11. Here, it is
assumed that a measurement result constituted by cells
using the carrier frequency f1 and a measurement result
constituted by cells using the carrier frequency f2 are
inputted. It is also assumed that an event causing
transmission of a measurement report to the base station
3 occurs in a serving cell using the carrier frequency f1
then. The measurement result reducing section 9 starts
judgment about whether the measurement result is
constituted by cells using the carrier frequency f1 or by
cells using the carrier frequency f2 (S301).
[0105]
If it is judged that the measurement result is
constituted by cells using the carrier frequency f1 at
which the event occurred (S302), it is judged whether the
cell quality is worse than the quality of the serving
cell with the carrier frequency f1 by a certain value (x
dB; for example, x=30) or more (S303). Such cells that
are judged to have a worse quality are deleted from the
measurement report (S304), and other cells are judged to
be included into the measurement report (S305).
[0106]

- 61 -

On the other hand, if it is judged that the
measurement result is constituted by cells using the
carrier frequency f2 at which an event has not occurred
(S302), it is judged whether the cell quality is worse
than the quality of the carrier frequency f1 by a certain
value (y dB; for example, y=40) or more (S306). Such
cells that are judged to have a worse quality are deleted
from the measurement report (S304), and other cells are
judged to be included into the measurement report (S305).
[0107]
As described above, the measurement result is
changed on the basis of a result of judging cells to be
deleted from the measurement report and cells to be
included into the measurement report (S307), and the
measurement result from which unnecessary cells have been
deleted, is outputted to the measurement report creating
section 7 (S308).
[0108]
Thus, by the measurement result reducing section 9
selecting cells to be included into a measurement report
on the basis of the quality of a serving cell with a
carrier frequency at which an event occurred, it is
possible to select cells using the carrier frequency at
which an event has occurred and cells using a carrier
frequency at which an event has not occurred, using the
same criterion.
[0109]

- 62 -

By changing the quality difference from a serving
cell from which it is judged whether or not to include a
cell into a measurement report, between a carrier
frequency at which an event has occurred and a carrier
frequency at which an event has not occurred, it is
possible to give priorities to cells to be included into
the measurement report. It is also possible to equalize
the quality difference from the serving cell between the
carrier frequency at which an event has occurred and the
carrier frequency at which an event has not occurred
without changing it between the carrier frequencies.
[0110]
Operations and advantages similar to those of the
first embodiment can be obtained by the wireless
communication system 1 of the third embodiment.
[0111]
In the wireless communication system 1 of this
embodiment, the measurement report creating section 7 is
configured to select a measurement report of the radio
condition of a cell judged to have a higher communication
quality in comparison with a predetermined reference
quality set at the frequency at which the event occurred.
[0112]
Due to this configuration, a predetermined reference
quality set at a frequency at which an event occurred and
the communication quality of cells are compared, and a
measurement report of the radio condition of a cell

- 63 -

judged to have a high communication quality is selected
as information indicating the radio condition of the cell.
Thereby, only such useful information (a measurement
report) is transmitted that the communication quality is
judged to be high, with the frequency at which the event
occurred used as a reference. That is, in this
embodiment, it is possible for the terminal apparatus 2
to communicate a better cell to the base station 3.
Furthermore, it is possible to reduce the data size of a
measurement report transmitted from the terminal
apparatus 2 to the base station 3 and reduce the amount
of traffic. The reference quality may be set in the
terminal apparatus 2 in advance or may be received from
the base station 3 and set in the terminal apparatus 2.
[0113]
(Fourth embodiment)
Next, the wireless communication system 1 of a
fourth embodiment of the present invention will be
described. Here, description will be made mainly on a point in which the wireless communication system 1 of this embodiment is different from the first embodiment. Therefore, the configuration and operation of this
embodiment are similar to those of the first embodiment unless otherwise especially referred to.
[0114]
In this embodiment, the operation of the measurement
result reducing section 9 performed when a measurement

- 64 -

report is created is different from that of the first
embodiment. Therefore, the operation of the measurement result reducing section 9 of the terminal apparatus 2 in the fourth embodiment will be described here with
reference to drawings.
[0115]
Figure 12 is a flowchart showing the operation of
the measurement result reducing section 9 of the fourth
embodiment. First, a measurement result constituted by
cells using the carrier frequency of each component
carrier is inputted to the measurement result reducing
section 9 (S400), as shown in Figure 12. Here, it is
assumed that a measurement result measurement result
constituted by cells using the carrier frequency f1 and a
measurement result constituted by cells using the carrier
frequency f2 are inputted. It is also assumed that an
event causing transmission of a measurement report to the
base station 3 occurs in a serving cell using the carrier
frequency f1 then. The measurement result reducing
section 9 starts judgment about whether the measurement
result is constituted by cells using the carrier
frequency f1 or by cells using the carrier frequency f2
(S401).
[0116]
If it is judged that the measurement result is
constituted by cells using the carrier frequency f1 at
which the event occurred (S402), it is judged whether the

- 65 -

cell quality is worse than the quality of the serving
cell with the carrier frequency f1 by a certain value (x
dB; for example, x=30) or more (S403). Such cells that
are judged to have a worse quality are deleted from the
measurement report (S404), and other cells are judged to
be included into the measurement report (S405).
[0117]
On the other hand, if it is judged that the
measurement result is constituted by cells using the
carrier frequency f2 at which an event has not occurred
(S402), it is judged whether the cell quality is worse
than the quality of a serving cell with the carrier
frequency f2 by a certain value (y dB; for example, y=40) or more (S406). Such cells that are judged to have a
worse quality are deleted from the measurement report
(S404), and other cells are judged to be included into
the measurement report (S405).
[0118]
From a result of judging cells to be deleted from
the measurement report and cells to be included into the
measurement report as described above, the measurement
result is changed (S407), and the measurement result from
which unnecessary cells have been deleted, is outputted
to the measurement report creating section 7 (S408).
[0119]
By the measurement result reducing section 9
selecting cells to be included into a measurement report

- 66 -
on the basis of quality difference from a serving cell, for each carrier frequency, it is possible to create a measurement report from which the base station 3 can
judge handover on the basis of the conditions of carrier frequencies being used.
[0120]
By changing the quality difference from a serving
cell from which it is judged whether or not to include a
cell into a measurement report, between a carrier
frequency at which an event has occurred and a carrier
frequency at which an event has not occurred, it is
possible to give priorities to cells to be included into
the measurement report. It is also possible to equalize
the quality difference from the serving cell between the
carrier frequency at which an event has occurred and the
carrier frequency at which an event has not occurred
without changing it between the carrier frequencies.
[0121]
Operations and advantages similar to those of the
first embodiment can be obtained by the wireless
communication system 1 of the fourth embodiment.
[0122]
In the wireless communication system 1 of this
embodiment, the measurement report creating section 7 is
configured to select a measurement report of the radio
condition of a cell judged to have a higher communication
quality in comparison with a predetermined reference

- 67 -
quality set for each frequency being used for communication.
[0123]
Due to this configuration, the communication
qualities of cells are compared at each frequency being
used for communication, and a measurement report of the
radio condition of a cell judged to have a high
communication quality is selected as information
indicating the radio condition of the cell. Thereby,
only such useful information that the communication
quality is judged to be high, with the frequency at which
an event occurred used as a reference, and such useful
information that the communication quality is judged to
be high, with another frequency as a reference (a
measurement report) are transmitted. That is, in this
embodiment, it is possible for the terminal apparatus 2
to communicate a better cell to the base station 3.
Furthermore, it is possible to reduce the data size of a
measurement report transmitted from the terminal
apparatus 2 to the base station 3 and reduce the amount
of traffic. The reference quality may be set in the
terminal apparatus 2 in advance or may be received from
the base station 3 and set in the terminal apparatus 2.
[0124]
(Fifth embodiment)
Next, the wireless communication system 1 of a fifth
embodiment of the present invention will be described.

- 68 -
Here, description will be made mainly on a point in which the wireless communication system 1 of this embodiment is different from the first embodiment. Therefore, the
configuration and operation of this embodiment are
similar to those of the first embodiment unless otherwise especially referred to.
[0125]
In this embodiment, the operation of the measurement result reducing section 9 performed when a measurement
report is created is different from that of the first
embodiment. Therefore, the operation of the measurement
result reducing section 9 of the terminal apparatus 2 in the fifth embodiment will be described here with
reference to drawings.
[0126]
Figure 13 is a flowchart showing the operation of
the measurement result reducing section 9 of the fifth
embodiment. First, a measurement result constituted by
cells using the carrier frequency of each component
carrier is inputted to the measurement result reducing
section 9 (S500), as shown in Figure 13. Here, it is
assumed that a measurement result measurement result
constituted by cells using the carrier frequency f1 and a
measurement result measurement result constituted by
cells using the carrier frequency f2 are inputted. Next,
priorities of the carrier frequencies (for example, f1
and f2 indicate a high priority and a low priority,

- 69 -
respectively) are inputted to the measurement result
reducing section 9 from the control section 6 (S501).
Then, the measurement result reducing section 9 judges
whether the measurement result is constituted by cells
using the frequency f1 with a high carrier frequency
priority (S502).
[0127]
If it is judged that the measurement result is
constituted by cells using the frequency f1 with a high
carrier frequency priority, the measurement result
reducing section 9 judges that the measurement result is
to be included into a measurement report (S503). On the
other hand, if it is judged that the measurement result
is constituted by cells using the frequency f2 with a low
carrier frequency priority, the measurement result
reducing section 9 judges that the measurement result is
not to be included into the measurement report (S504).
[0128]
As described above, the measurement result is
changed on the basis of a result of judging cells to be
deleted from the measurement report and cells to be
included into the measurement report (S505), and the
measurement result from which unnecessary cells have been
deleted, is outputted to the measurement report creating
section 7 (S506).
[0129]

- 70 -
Thus, by the measurement result reducing section 9
selecting cells to be included into a measurement report
according to priorities of carrier frequencies, it is
possible to create a measurement report which includes
only such cells that are judged to have a high
probability of being used for handover.
[0130]
Operations and advantages similar to those of the
first embodiment can be obtained by the wireless
communication system 1 of the fifth embodiment.
[0131]
In the wireless communication system 1 of this
embodiment, priorities at the time of performing handover
are set for multiple frequencies, respectively, in the
terminal apparatus 2, and the measurement report creating
section 7 is configured to select a measurement report of
a frequency selected on the basis of the priorities, from
among measurement reports of cells at multiple
frequencies, as information indicating the radio
conditions of cells at another frequency.
[0132]
Due to this configuration, a measurement report of a
frequency selected from among measurement reports of
cells at multiple frequencies on the basis of the
handover priorities set in the terminal apparatus 2 is
selected as information indicating the radio conditions
of cells at another frequency. That is, cells to be

- 71 -
included into a measurement report are selected on the
basis of priorities given to the terminal apparatus 2
from the base station 3. Therefore, in comparison with
the case of including all the measurement reports of the
multiple frequencies, the data size of the measurement
report to be transmitted from the terminal apparatus 2 to
the base station 3 can be reduced, and it becomes
possible to reduce the amount of traffic. The priorities
may be set in the terminal apparatus 2 in advance or may
be received from the base station 3 and set in the
terminal apparatus 2.
[0133]
(Sixth embodiment)
The wireless communication system of this embodiment
is characterized in measurement configuration. According
to the measurement configuration of this embodiment, it
is possible to collect multiple frequency measurement
results into one measurement report. Though there are
some examples of such measurement configuration, three
main examples will be described below. That is, the
description below is on examples of the measurement
configuration of the present invention, and it goes
without saying that other measurement configurations may
be used.
[0134]
As shown in Figure 17, a first example is
configuration in which one measurement object identity

- 72 -

(MeasObjectID) and one report configuration identity
(ReportConfigID) are combined with one measurement
identity (MeasID). In this case, it is necessary that a
method for collecting measurement results obtained by
performing measurement with different measurement
identities (MeasIDs) into one measurement report is
notified from the base station 3 to the terminal
apparatus 2 or known by the terminal apparatus 2 in
advance. As for the method for collecting the
measurement results into one measurement report, there
are some such methods.
[0135]
A first method is as follows. Measurement results
to be periodically sent and measurement results to be
sent at the time of occurrence of an event are separated,
and the measurement results to be periodically sent are
collected into one measurement report, and the
measurement results to be sent at the time of occurrence
of an event are collected into one measurement report.
Thereby, measurement reports with different purposes,
that is, the measurement results to be periodically sent
and the measurement results to be sent at the time of
occurrence of an event can be separately sent, so that
the base station 3 can easily perform control. The
terminal apparatus 2 also can easily select cells to be
included into a measurement report.
[0136]

- 73 -

A second is a method of collecting measurement
results into one measurement report for each event set in
report configuration (ReportConfig). Thereby, it is
possible to send a measurement report for each event, and
therefore, it is possible to send measurement reports
according to purposes in more detail. Thus, the base
station 3 can know conditions of the terminal apparatus 2
resembling each other among frequencies and, therefore,
can easily perform control. The terminal apparatus 2
also can easily select cells to be included into a
measurement report.
[0137]
A third is a method of collecting measurement
results to be sent at the time of occurrence of an event into one measurement report without collecting
measurement results to be periodically sent. Thereby,
since it is possible to collectively send measurement
reports to be sent at the time of occurrence of an event, the base station 3 can easily perform control. The
terminal apparatus 2 also can easily select cells to be included into a measurement report.
[0138]
A fourth is a method of collecting measurement
results into one measurement report for each event set in
report configuration (ReportConfig) without collecting
measurement results to be periodically sent. Thereby, it
is possible to collectively send measurement reports each

- 74 -

of which is to be sent for each event. Thus, the base
station 3 can know conditions of the terminal apparatus 2
resembling each other among frequencies and, therefore,
can easily perform control. The terminal apparatus 2
also can easily select cells to be included into a
measurement report. Thereby, existing configuration can
be used. In methods other than this method, it is
possible to collect measurement results into one
measurement result by using the first example.
[0139]
A method is also possible in which, by setting
multiple frequencies for a measurement object
(MeasObject), multiple frequency measurement results are
collected into one measurement report. Thereby, it is
possible to easily collect measurement results for each
event.
[0140]
As shown in Figure 21, a second example is
configuration in which multiple measurement object
identities (MeasObjectIDs) and one report configuration
identity (ReportConfigID) are combined with one
measurement identity (MeasID). Thus, by collecting
measurement object identities (MeasObjectIDs)
corresponding to only one frequency and combining them
with one measurement identity (MeasID), the base station
3 can notify measurement configuration for collecting
multiple frequency measurement results into one

- 75 -

measurement report, to the terminal apparatus 2. The
base station 3 can set cells which the terminal apparatus
2 is to include into one measurement report, according to
purposes. Since the terminal apparatus 2 only has to
send one measurement report for each measurement
configuration indicated by a measurement identity
(MeasID), it is easy to select cells to be included into
a measurement report. Since the terminal apparatus 2
only has to send one measurement report for each
measurement configuration, it is one measurement identity
that is to be included into a measurement report, and
therefore, the measurement report format can be
simplified.
[0141]
A third example is configuration in which a
measurement object list ID (MeasObjectListID) is newly
provided, and one measurement object identity
(MeasObjectID) and one report identity (ReportConfigID)
are combined with one measurement identity (MeasID). The
measurement object list ID (MeasObjectListID) is an
identity for combining multiple measurement object
identities (MeasObjectIDs) with one another. Thereby,
advantages similar to those of the second example can be
obtained. Furthermore, by introducing the measurement
object list ID (MeasObjectListID), the measurement
configuration format can be obtained only addition to an

- 76 -
existing format, and therefore, backward compatibility is improved.
[0142]
(Seventh embodiment)
The wireless communication system of this embodiment
is characterized in configuration of a serving cell.
That is, the terminal apparatus 2 uses the received
quality of a serving cell as a criterion for judging an
event after starting measurement. Though there are some
examples of this serving cell configuration, five main
examples will be described below. That is, the
description below is on examples of serving cell
configuration of the present invention, and it goes
without saying that a serving cell may be configured in
other methods. This serving cell configuration is
performed by the control section 6 of the terminal
apparatus 2. Therefore, the control section 6 of the
terminal apparatus 2 can be said to be serving cell
configuration means.
[0143]
A first example is a method of configuring one cell
as a serving cell. There are some methods for selecting
a serving cell. A first is a method in which a cell to
be used as a serving cell is notified to the terminal
apparatus 2 from the base station 3. A second is a
method in which a cell which is for the terminal
apparatus 2 maintaining connection with the base station

- 77 -
3 (for example, performing security management) and which
is called a special cell or an anchor carrier, is
configured as a serving cell. A third is a method in
which a cell (or component carrier) with the best
received quality is configured as a serving cell from
among cells (or component carriers) which can be used as
a serving cell. Thereby, if the radio condition of at
least one of component carriers used by the terminal
apparatus 2 is good, an event does not easily occur and a
measurement report is not easily sent. Therefore, it is
possible to reduce useless measurement reports. A fourth
is a method in which a cell (or component carrier) with
the worst received quality is configured as a serving
cell from among cells (or component carriers) which can
be used as a serving cell. Thereby, if the radio
condition of at least one of component carriers used by
the terminal apparatus 2 is good, an event easily occurs
and a measurement report is easily sent. Therefore, it
is possible to perform mobility control earlier.
[0144]
A second example is a method of configuring one for
each measurement object (MeasObject). This is a method
in which, if the frequency handed over to a measurement
object is used by the terminal apparatus 2, the cell (or
component carrier) is used as a serving cell. Thereby,
event judgment in consideration of characteristics for
each frequency is performed, and therefore, a more

- 78 -

suitable measurement report can be sent. Therefore,
mobility control can be appropriately performed. As for
frequencies which are not used by the terminal apparatus
2, there are some methods. A first is a method in which
a cell (or component carrier) to be used as a serving
cell is notified from the base station 3 to the terminal
apparatus 2. A second is a method in which a special
cell is used as a serving cell. A third is a method in
which a cell (or component carrier) with the best
received quality, among cells (or component carriers)
being used, is used as a serving cell. A fourth is a
method in which a cell (or component carrier) with the
worst received quality, among cells (or component
carriers) being used, is used as a serving cell. A fifth
is a method in which the closest cell (or component
carrier), among cells (or component carriers) being used,
is used as a serving cell. A sixth is a method in which
the closest cell (or component carrier), among cells (or
component carriers) belonging to the same frequency band
and being used, is configured as a serving cell. A
method may be used in which the above methods are
switched for each event. Thereby, it is possible to
cause an event to easily occur or not to easily occur in
accordance with the characteristics of events.
[0145]
A third example is a method in which a serving cell is configured for each component carrier to which a

- 79 -
physical downlink control channel (hereinafter referred
to simply as a "PDCCH") is sent. As for a cell (or
component carrier) to which the PDCCH has not been sent,
among frequencies being used, a cell (or a component
carrier) which sends a PDCCH indicating a physical
downlink shared channel (hereinafter referred to simply
as a "PDSCH") of the cell (or component carrier) is used
as a serving cell. Thereby, event judgment in
consideration of characteristics for each frequency is
performed while the number of serving cells is limited,
and therefore, a suitable measurement report can be sent.
Therefore, mobility control can be appropriately
performed. As for frequencies which are not used, the
same as the above second example is applied.
[0146]
A fourth example is a method in which a serving cell
is configured by notifying the serving cell from the base
station 3 to the terminal apparatus 2. For example, a
800-MHz band and a 2-GHz band are used at the same time,
one serving cell is configured for each of the 800-MHz
band and the 2-GHz band. Thereby, event judgment in
consideration of characteristics for each frequency is
performed while the number of serving cells is suppressed
more, and therefore, a suitable measurement report can be
sent. Therefore, mobility control can be appropriately
performed.
[0147]

- 80 -
A fifth example is a method in which a serving cell
is notified for each report configuration (ReportConfig)
and configured. For example, 1 bit is used to notify
that one cell is used as a serving cell or that multiple
cells are used as serving cells. Thereby, it is possible
to use both of the case of using one cell as a serving
cell and the case of using multiple cells as serving
cells. The one cell may be configured by the method of
the above first example. The multiple cells may be
configured by the methods of the above second and third
examples.
[0148]
A sixth example is a method in which a serving cell
is notified for each measurement identity (MeasID) and
configured. For example, 1 bit is used to notify that
one cell is used as a serving cell or that multiple cells
are used as serving cells. Thereby, it is possible to
use both of the case of using one cell as a serving cell
and the case of using multiple cells as serving cells.
Furthermore, thereby, the amount of information for
configuration can be reduced. The one cell may be
configured by the method of the above first example. The
multiple cells may be configured by the methods of the
above second and third examples.
[0149]
When the terminal switches the component carrier to
be used for carrier aggregation (at the time of handover

- 81 -
and at the time of re-establishment, or at the time of
notification of switching from the base station), it is
possible to switch measurement configuration, following
switching of the component carrier to be used, without a
notification of change in the measurement configuration.
For example, this is a method of, when a method of
switching a measurement object identity (MeasObjectID)
associated with a measurement identity (MeasID) is
executed, switching a serving cell also.
[0150]
Description will be made below on the case where a
serving cell is associated with each measurement identity
(MeasID) as an example. Description will be made also on
the case where, when performing carrier aggregation using
the component carriers of f1 and f2, the terminal
switches the carrier aggregation to carrier aggregation
using the component carriers of f2 and f3 as an example.
[0151]
At this time, the terminal does not change the
measurement configuration of the component carrier of f2
because it continues using the component carrier of f2.
When a measurement identity (measID: 1) and serving cells
(multiple serving cells are used as serving cells (f1))
are associated with a measurement object identity of f1
(MeasObjectID: 1), and a measurement identity (measID: 3)
and a serving cell (one cell is used as a serving cell
(f2)) are associated with a measurement object identity

- 82 -

of f3 (MeasObjectID: 3), then the association of the
measurement identity (measID: 1) is switched to
association with a measurement object identity
(MeasObjectID: 3) and serving cells (multiple serving
cells are used as serving cells (f3)), and the
association of the measurement identity (measID: 3) is
switched to association with the measurement object
identity (MeasObjectID: 1) and the serving cell (one cell is used as a serving cell (f2)).
[0152]
Thereby, it is possible to continue using
measurement configuration associated with a measurement
identity (MeasID) to perform measurement within the same
frequency and measurement configuration associated with a
measurement identity (MeasID) to perform measurement
between different frequencies while maintaining the
purposes. The serving cells is changed according to the
carrier frequency of an associated measurement object
identity (MeasObjectID), though whether one cell is used
as a serving cell or multiple cells are used as serving
cells is kept being associated with a measurement
identity (MeasID).
[0153]
Even in the case where there are multiple candidates
for switching, the present invention can be applied by
judging whether the purpose is measurement within a
frequency or measurement among frequencies, because the

- 83 -
present invention is characterized in maintaining a purpose.
[0154]
For example, if multiple measurement object
identities (MeasObjectIDs) can be associated with a
measurement identity, and the terminal switches carrier
aggregation with two component carriers to carrier
aggregation with three component carriers, association
with a measurement object identity (MeasObjectID) and
serving cells corresponding to a purpose is performed.
If multiple measurement identities cannot be associated
with a measurement identity, it is possible to switch the
association for a measurement object identity for which a
measurement identity corresponding to a purpose exists,
and release association for a measurement object identity
for which a measurement identity corresponding to a
purpose does not exist.
[0155]
If multiple measurement identities cannot be
associated with a measurement identity, it is possible to
associate measurement object identities with the
measurement identity by giving priorities, and release
the existing association for such a measurement object
identity that cannot be associated with a measurement
identity corresponding to a purpose. Priorities are
given so that those which have been used are
preferentially maintained. A measurement identity of a

- 84 -

carrier frequency belonging to the same band as the
carrier frequency of a measurement object identity
associated with a measurement identity may be prioritized. [0156]
Thereby, parameters for measurement configuration
associated with a measurement identity easily become more
appropriate. In addition, a higher priority may be given
to an anchor carrier, a carrier with a good received
quality, a carrier through which the terminal receives a
PDCCH, or the like. If a measurement identity
corresponding to a purpose does not exist, the
measurement configuration therefor may be deleted.
[0157]
(Eighth embodiment)
The wireless communication system of this embodiment
is characterized in configuration of a serving cell to be
a criterion at the time of performing Inter-RAT. In
measurement configuration for a different radio access
technique (Inter-RAT: Inter Radio Access Technology),
there is an event called an event B2 (a serving cell is
below a threshold 1, and an Inter-RAT cell is above a
threshold 2). At this time, the thresholds 1 and 2 are
included in the measurement configuration. Though there
are some configurations of a serving cell to be a
criterion, six main examples will be described below.
That is, the description below is on examples of serving
cell configuration of the present invention, and it goes

- 85 -

without saying that other methods may be used. This
serving cell configuration is performed by the control
section 6 of the terminal apparatus 2. Therefore, the
control section 6 of the terminal apparatus 2 can be said to be serving cell configuration means.
[0158]
A first example is a method in which, when the
reception qualities of all serving cells set as serving
cells are below the threshold 1, it is judged that a part
of the event B2 (a serving cell is below a threshold 1)
is satisfied. Thereby, the terminal apparatus 2 can
preferentially use E-UTRA when E-UTRA can be used.
[0159]
A second example is a method in which, when the
reception qualities of all cells (or component carriers) being used, among serving cells set as serving cells, are below the threshold 1, it is judged that a part of the
event B2 (a serving cell is below a threshold 1) is
satisfied. Thereby, the terminal apparatus 2 can
preferentially use E-UTRA when it is possible to continue using E-UTRA being used.
[0160]
A third example is a method in which, when the
received quality of one serving cell, among serving cells
set as serving cells, is below the threshold 1, it is
judged that a part of the event B2 (a serving cell is
below a threshold 1) is satisfied. Thereby, the terminal

- 86 -

apparatus 2 can quickly look for an appropriate RAT
checking the conditions of other RATs if at least a part of the condition of E-UTRA gets worse.
[0161]
A fourth example is a method in which, when the
received quality of one serving cell, among cells (or
component carriers) being used among serving cells set as
serving cells, is below the threshold 1, it is judged
that a part of the event B2 (a serving cell is below a
threshold 1) is satisfied. Thereby, the terminal
apparatus 2 can quickly look for an appropriate RAT
checking the conditions of other RATs if at least a part
of the condition of E-UTRA being used gets worse.
[0162]
A fifth example is a method in which, when the
average of the reception qualities of all serving cells
set as serving cells are below the threshold 1, it is
judged that a part of the event B2 (a serving cell is
below a threshold 1) is satisfied. Thereby, it is
possible to impartially handle E-UTRA and RAT.
[0163]
A sixth example is a method in which, when the
average of the reception qualities of all cells (or
component carriers) being used, among serving cells set
as serving cells, are below the threshold 1, it is judged
that a part of the event B2 (a serving cell is below a
threshold 1) is satisfied. Thereby, it is possible to

- 87 -
impartially handle E-UTRA and RAT being used by the terminal apparatus 2.
[0164]
(Ninth embodiment)
The wireless communication system of this embodiment
is characterized in a method for selecting a serving cell
to be included into a measurement report. Here, a method
for selecting a serving cell to be included into a
measurement report at the time of performing Inter-RAT.
Though there are some methods for selecting a serving
cell to be included into an Inter-RAT measurement report,
four main examples will be described below. That is, the
description below is on examples of a serving cell
selection method of the present invention, and it goes
without saying that other methods may be used. Selection
of a serving cell to be included into a measurement
report is performed by the control section 6 of the
terminal apparatus 2. Therefore, the control section 6
of the terminal apparatus 2 can be said to be serving
cell selection means.
[0165]
A first example is a method of including all of
measurement results of cells (or component carriers) set
as serving cells. Thereby, the base station 3 can know
the conditions of all the cells (or component carriers)
set as serving cells and, therefore, can know the
conditions of all the cells which it wants to know, and

- 88 -
appropriately select a component carrier to be used by the terminal apparatus 2.
[0166]
A second example is a method of including all of
measurement results of cells (or component carriers)
being used by the terminal apparatus 2, among cells (or component carriers) set as serving cells. Thereby, the base station 3 can grasp the condition of the use by the terminal apparatus 2 and, therefore, can appropriately
select a cell (or component carrier) to be used by the
terminal apparatus 2.
[0167]
A third example is a method of including a
measurement result of a cell (or component carrier) with the worst received quality among cells set as serving
cells. Thereby, the base station 3 can judge whether it is necessary to switch the component carrier used by the terminal apparatus 2.
[0168]
A fourth example is a method of including a
measurement result of a cell (or component carrier) with the best received quality among cells set as serving
cells. Thereby, the base station 3 can judge whether the terminal apparatus 2 can keep connection.
[0169]
Next, a method for selecting a serving cell to be included into a measurement report in the case

- 89 -
measurement configuration for measurement within E-UTRAN
is set. When the measurement configuration for
measurement within E-UTRAN is set, there are some
examples of a serving cell selection method at the time
of an event A1 (a serving cell is above a threshold), an
event A2 (a serving cell is below a threshold), an event
A3 (a neighbor cell is better than a serving cell), and
an event 4 (a neighbor cell is better than a threshold),
and an event A5 (a serving cell is worse than a threshold
1 and a neighbor cell is better than a threshold 2).
Though five main examples will be described below, they
are examples of the serving cell selection method of the
present invention, and it goes without saying that other
methods may be used, similarly as described above.
[0170]
A first example is a method of including all of
cells (or component carriers) set as serving cells.
Thereby, the base station 3 can know the conditions of
all the cells (or component carriers) set as serving
cells and, therefore, can know the conditions of all the
cells which it wants to know, and appropriately select a
component carrier to be used by the terminal apparatus 2.
[0171]
A second example is a method of including all of
cells (or component carriers) being used, among cells (or
component carriers) set as serving cells. Thereby, the
base station 3 can grasp the condition of the use by the

- 90 -
terminal apparatus 2 and, therefore, can appropriately select a cell (or component carrier) to be used by the terminal apparatus 2.
[0172]
A third example is a method of including only a
serving cell among cells (or component carriers) where an
event has occurred, among cells (or component carriers)
set as serving cells. Thereby, if there is a cell (or
component carrier) to be compared, the base station 3 can
know a measurement result of the serving cell.
[0173]
A fourth example is a method of including a
measurement result of a serving cell with a frequency at
which there is a cell (or component carrier) other than a
serving cell to be included into a measurement report,
among cells set as serving cells. Thereby, if there is a
cell (or component carrier) to be compared, the base
station 3 can know a measurement result of the serving
cell.
[0174]
A fifth example is a method of including a
measurement result of a serving cell with a frequency at
which there is a measurement object (MeasObject)
corresponding to a measurement identity (MeasID) of
measurement for which a measurement report is to be sent,
among cells set as serving cells. Thereby, it is

- 91 -
possible to prevent a useless serving cell measurement result from being sent.
[0175]
If the same serving cell is used among multiple
frequencies, a measurement result of the serving cell may not be included for each frequency. Thereby, it is
possible to prevent a useless serving cell measurement result from being included.
[0176]
As described above, if all of cells (or component
carriers) set as serving cells are included into a
measurement report, all of set frequencies can be
considered to perform handover. Therefore, if there is a
better cell (or component carrier), the cell (or
component carrier) can be used. If a part of the cells
(or component carriers) set as serving cells are included,
it is possible to consider only a frequency satisfying
conditions. Therefore, it is possible to compare cells
(or component carriers) with a frequency used by the
terminal apparatus 2 and select a better one while
suppressing resources.
[0177]
(Tenth embodiment)
The wireless communication system of this embodiment
is characterized in setting of a threshold for each
frequency at the time of the event A1 (a serving cell is
above a threshold), the event A2 (a serving cell is below

- 92 -
a threshold), the event 4 (a neighbor cell is better than a threshold), and the event A5 (a serving cell is worse
than a threshold 1 and a neighbor cell is better than a
threshold 2).
[0178]
If there is one measurement configuration identity
(ReportConfigID) to be combined with a measurement
identity (MeasID), the threshold used for event judgment
at the events A1, A2, A4 and A5 is equal among
frequencies. Even if the threshold is equal among
frequencies, it is possible to add an offset to the
threshold for each frequency without adding an offset to
report configuration (ReportConfig) by utilizing an
offset included in a measurement object (MeasObject).
Therefore, it is possible to perform event judgment in
consideration of frequency characteristics without adding
overhead to the report configuration (ReportConfig).
[0179]
(Eleventh embodiment)
The wireless communication system of this embodiment
is characterized in a method for selecting a cell to be
included into a measurement report at the time of handing
over cell pair information. This cell selection is
performed by the control section 6 of the terminal
apparatus 2. Therefore, the control section 6 of the
terminal apparatus 2 can be said to be cell selection
means.

- 93 -

[0180]
The cell selection method of this embodiment will be
described with the use of an example in Figure 23. As
shown in Figure 23, three pairs are formed in this
example. A first pair (pair A) is constituted by cells 1,
4 and 7; a second pair (pair B) is constituted by cells 2,
5 and 8; and a third pair (pair C) is constituted by
cells 3, 6 and 9. The cells 1, 2 and 3 are cells with
the frequency f1; the cells 4, 5 and 6 are cells with the
frequency f2; and the cells 7, 8 and 9 are cells with the
frequency 3.
[0181]
Such sell pair information is set by the base
station 3. The cell pair information may be communicated to the terminal apparatus 2 by a definite control signal. Alternatively, a method is also possible in which the
cell pair information is communicated to the terminal
apparatus 2 only with the same information as before, for example, on the assumption that cells having the same
cell ID (PCI) are paired.
[0182]
The terminal apparatus 2 uses the cells belonging to
the pair A as serving cells. If an event occurs in the
cell 2, the cells 1, 4 and 7 are included into a
measurement report as serving cells, and the cell 2 where
the event occurred is included into the measurement
report as a concerned cell. Furthermore, the cells 5 and

- 94 -
8 belonging to the same pair B as the cell 2 are included
into the measurement report as associated cells. Thereby,
carrier aggregation can be switched to a more appropriate
pair.
[0183]
Here, the case of including measurement results of
the concerned cell (cell 2) and the associated cells
(cells 5 and 8) in addition to measurement results of the multiple serving cells (cells 1, 4 and 7) has been
described as an example. However, the scope of the
present invention is not limited thereto. For example,
the measurement result of the associated cell is not
necessarily to be included, and, as for the measurement results of the serving cells, the measurement result only one serving cell may be included.
[0184]
(Twelfth embodiment)
The wireless communication system of this embodiment
is characterized in the format of a measurement report.
Here, there is shown, first, an example of a measurement
report in the case of including measurement results of
multiple measurement identities (MeasIDs) into one
measurement report as shown in the first example in the
sixth embodiment (measurement configuration). Two main
examples will be described below. However, it goes
without saying that the present invention is not limited
thereto.

- 95 -

[0185]
A first example is an example of the case where a
measurement report format is newly generated without
adding a measurement report format to an existing format.
Figure 24 is a diagram showing an example of adding a new
measurement report format into MeasurementReport. In the
example in Figure 24, measurementReport-r10 is added into
MeasurementReport so that measurementReport-r10 can be
selected to use the new format and measurementReport-r8
can be selected to use the old existing format. The new
format is constituted by measResults-r10 and
nonCriticalExtension.
[0186]
Figure 25 shows a part of the configuration of
MeasResults-r10, which is the contents of measResults-r10.
Omitted components are similar to those of Non Patent
Literature 1. Figure 25 is a diagram showing the
component MeasResults-r10 which is added as a component
of the new format of MeasurementReport in Figure 24.
MeasResults-r10 is constituted by measResultsSet-r10.
MeasResultsSet-r10, which is the contents of
measResultsSet-r10, is constituted by the number of
MeasResults used in the old existing format equal to or
less than number. Thereby, the existing components can
be used and, therefore, it is possible to collect
measurement results corresponding to multiple measurement

- 96 -
identities into one measurement report while decreasing
the number of components to be newly provided.
[0187]
In this case, as for the measurement results to be
included into the one measurement report, only those
judged to be collected into one measurement report can be
included. The method assumes that serving cell
measurement results are included for each of measurement
identities (MeasIDs) to be included into a measurement
report. However, by causing serving cell measurement
results to be optionally selected, it is possible to
flexibly select serving cell measurement results to be
included, for example, select including only one serving
cell measurement result or select including only a
measurement result of a criterion serving cell.
[0188]
A second example is an example of the case where a
measurement report format is added to an existing format,
and the example is shown in Figure 26. In Figure 26,
measResults-v10x0 is added to MeasResults, and
measResults-v10x0 is constituted by MeasResultsSet-r10.
MeasResultsSet-r10 is constituted by MeasResults-r10.
The configuration of MeasResults-r10 is almost the same
as that of MeasResults. However, measResultServCell is
OPTIONAL. Thereby, at the time of including measurement
results corresponding to multiple measurement identities
(MeasIDs) into one measurement report, only one serving

- 97 -
cell measurement result can be included. Thereby, at the time of including measurement results corresponding to multiple measurement identities (MeasIDs) into one
measurement report, only measurement results of a
criterion serving cell can be included as serving cell measurement results to be included.
[0189]
In the case of including a serving cell measurement
result for each measurement identity (MeasID), positions
to be changed can be reduced because MeasResults-r10 can
be set to be the same as MeasResults. In the case of
including only one serving cell measurement result into a
measurement report, measResultServCell may be erased from
MeasResults-r10. Thereby, bits (information) for
OPTIONAL can be decreased. Omitted components are
similar to those of Non Patent Literature 1.
[0190]
Next, there will be shown an example of a
measurement report in the case of including a measurement
result based on measurement configuration for one
measurement identity (MeasID) into one measurement report
as shown in the second or third example in the sixth
embodiment (measurement configuration). Two main
examples will be described below. However, it goes
without saying that the present invention is not limited
thereto.
[0191]

- 98 -

A first example is an example of the case where a
measurement report format is newly generated without
adding a measurement report format to an existing format.
The example of adding a new measurement report format
into MeasurementReport is the same as Figure 24. Figure
27 shows a part of the configuration of MeasResults-r10,
which is the contents of measResults-r10. MeasResults-
r10 is constituted by measId and measResultsSet-r10.
MeasResultsSet-r10 is constituted by the number of
MeasResultsBody-r10's equal to or less than number.
MeasResultsBody-r10 is the old existing format
MeasResults in which measID is changed to measObjectID.
Thereby, it is possible to include information about
which frequency is corresponded. By setting a serving
cell measurement result to be included into a measurement
report as OPTIONAL, it is possible to select a serving
cell measurement result to be included into a measurement
report.
[0192]
Because measObjectID is for indicating frequency
information, it can be replaced with such that indicates
frequency information. If it is known that only one
serving cell measurement result is to be included,
measResultsServCell may be included into MeasResults-r10
and deleted from MeasResultsBody-r10. Thereby, bits
(information) for OPTIONAL can be decreased. Omitted

- 99 -
components are similar to those of Non Patent Literature
1.
[0193]
A second example is an example of the case where a
measurement report format is added to an existing format,
and the example is shown in Figure 28. Figure 28 is
almost the same as Figure 26. The figures are different
only in that measID in MeasResults-r10 in Figure 26 is
replaced with measObjectID in MeasResults-r10 in Figure
28. Thereby, it is possible to judge which frequency an
added part belongs to. At this time, by setting
information to be included into the existing format part
as anchor carrier or special cell information, it is
possible to separate information to be included into the
existing format part and information to be included into
a new format part.
[0194]
In addition to the above information, the
information to be included into the existing format part
may be determined in other methods such as determining
information having the smallest MeasObjectID to be the
information to be included. It is also possible to use
such that indicates frequency information instead of
MeasObjectID. In the case of including only one serving
cell measurement result, it is possible to use the format
in Figure 6.
[0195]

- 100 -

In the case where multiple measurement objects
(MeasObjects) are combined with a measurement identity
(MeasID), that is, in the case of the second or third
example in the sixth embodiment (measurement
configuration), RSRQ may be included in addition to RSRP.
Thereby, it is possible to select an appropriate cell in
consideration of interference also. In the case of
including a serving cell with a frequency for which a
measurement object (MeasObject) is not set, it is made
possible by providing a line for inputting a set of
serving cells.
[0196]
(Thirteenth embodiment)
The wireless communication system of this embodiment
is characterized in selection of a cell to be included
into a measurement report at the time of performing
periodical reporting. If sending a report periodically
(periodic reporting) is set, the terminal apparatus 2
sends a serving cell and a strongest cell by including
them into a measurement report. The strongest cell
refers to a cell with a high received power (may refer to
multiple cells with a high received power), and it does
not necessarily refer to only one cell with the highest
received power. In this case, the number of the
strongest cells to be included is restricted to some
extent, and there are some methods for selecting the
strongest cells. Three main examples of cell selection

- 101 -
will be described below. However, it goes without saying that other methods may be used. Selection of the
strongest cells is performed by the control section 6 of the terminal apparatus 2. Therefore, the control section 6 of the terminal apparatus 2 can be said to be strongest cell selection means.
[0197]
A first example is a method of sequentially
including cells into a measurement report in descending
order with a cell with the highest received power at the
top, irrespective of frequency. A second example is a
method in which one cell with a high received power is
included for each frequency, and, if there is left space
for including strongest cells, cells are sequentially
included into a measurement report in descending order
with a cell with the highest received power at the top,
irrespective of frequency. Thereby, the base station 3
can know each of information about frequencies at which a
periodic report is to be sent, without causing lack of
balance among frequencies. A third example is a method
of sequentially including cells into a measurement report
in descending order with a cell with the highest received
power at the top for each frequency so that the number of
cells is almost the same among frequencies. In this case,
if the same number of cells are not included for all the
frequencies, there are two kinds of frequency selections
for increasing the number of cells. A first is a method

- 102 -

in which a lot of cells with a lower received power,
among strongest cells, are preferentially included. A
second is a method in which a lot of cells with a high
received power, among strongest cells, are preferentially
included. These methods can be applied to the case of
periodically sending a report after occurrence of an
event.
[0198]
The embodiments of the present invention have been
described above with the use of examples. However, the
scope of the present invention is not limited thereto,
and modifications/variations can be made according to
purposes within the scope described in the claims.
[0199]
For example, though the first to thirteenth
embodiments have been separately described in the above description, the scope of the present invention is not limited thereto. These embodiments can be used in
combination with one another.
[0200]
Furthermore, in the above description, a method has
been described as an example in which the measurement
result reducing section 9 selects a cell to be included
into a measurement report from a carrier frequency
measurement result of a components carrier which is
already used by the terminal apparatus 2. However, even
in the case where a cell using the carrier frequency of a

- 103 -
component carrier which is not used by the terminal apparatus 2 is included in a measurement result, the above embodiments can be used.
[0201]
Furthermore, in the above description, an example
has been given in which, when the terminal apparatus 2 is
performing band aggregation, the cell quality is
described with RSRP if a measurement report is created on
the basis of only a measurement result based on the
carrier frequency of one component carrier, and the cell
quality is described with RSRQ if the measurement report
is created by including a measurement result based on the
carrier frequency of the other component carrier also.
However, it is also possible to include a flag indicating
whether to create a measurement report on the basis of
only a measurement result based on the carrier frequency
of one component carrier or to set the measurement report
which includes a measurement result based on the carrier
frequency of the other component carrier also, into the
measurement report for distinction.
[0202]
Furthermore, in the above description, when the
measurement result reporting criterion is satisfied at
the carrier frequency of one component carrier when the
terminal apparatus 2 is performing band aggregation, it
is judged whether all of measurement results based on the
carrier frequency of the other component carrier are to

- 104 -
be included into a measurement report. However, as shown
in Figure 14, the judgment may be performed only when an
event causing transmission of a measurement report occurs,
and judgment about whether or not to include a
measurement result based on the carrier frequency of the
other component carrier into a measurement report may not
be performed in the case of periodically reporting a
measurement result after occurrence of an event and the
case of periodically reporting a measurement result.
Furthermore, it may be judged that a measurement result
based on the carrier frequency of the other component
carrier is to be included only in the case where an event
causing transmission of a measurement report occurs and
in the case of periodically reporting a measurement
result after occurrence of an event, and it may not be
judged that a measurement result based on the carrier
frequency of the other component carrier is to be
included, in the case of periodically reporting a
measurement result.
[0203]
Furthermore, it is possible to apply the present
invention only in the case where band aggregation is
performed with the use of different frequency bands (for
example, a 800-MHz band and a 2-GHz band) and not to
apply the present invention in the case where band
aggregation is performed with the use of the same
frequency band. Thereby, it is possible to send

- 105 -
information required for decision of handover to the base
station 3 while suppressing processing required for the
terminal apparatus 2 to set a measurement report. Even
in the case of performing band aggregation using the same
frequency band, it is possible to determine whether or
not to apply the present invention according to the
degree of difference between frequencies and the radio
condition.
[0204]
Preferable embodiments of the present invention
conceivable at present have been described. It is
intended that it is understood that various variations of
the embodiments are possible, and that all such
variations within the true spirit and scope of the
present invention are included in the accompanying claims.

Industrial Applicability
[0205]
As described above, the wireless communication
system according to the present invention is a wireless
communication system in which a base station and a
terminal apparatus are communicable with each other using
multiple frequencies, and the wireless communication
system has an advantage of being capable of shortening
time required for handover and is useful as a wireless
communication system using LTE or SAE, and the like.

- 106 -
Reference Signs List
[0206]
1 Wireless Communication System
2 Terminal Apparatus
3 Base Station
4 Reception Section
5 Measurement Information Managing Section
6 Control Section
7 Measurement Report (MR) Creating Section
8 Transmission Section
9 Measurement Result Reducing Section
10 Reception Section
11 Measurement Information Managing Section 12 Handover (HO) Judgment Processing Section 13 Control Section
14 Transmission Section
15 Judgment Processing Section for Band-Aggregation 16 Normal Judgment Processing Section

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We Claim:
[Claim 1]
A terminal apparatus used in a wireless
communication system in which a base station apparatus
and the terminal apparatus are communicable with each
other using multiple frequencies, the terminal apparatus
comprising:
an event detecting section that detects occurrence
of an event for transmitting a measurement report of a
radio condition of a cell at a frequency set for the base station apparatus, to the base station communicating with the terminal apparatus; and
a measurement report creating section that creates the measurement report including information indicating radio conditions of the cells at a frequency at which the event occurred and at another different frequency, on the basis of occurrence of the event; and
the base station apparatus controlling whether or not to perform handover to the cell of the terminal apparatus on the basis of the measurement report
transmitted from the terminal apparatus.

[Claim 2]
The terminal apparatus according to claim 1, wherein
the measurement report creating section selects a part of
the measurement report of the radio conditions of the
cells at the frequency at which the event occurred and

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the other different frequency, as the information
indicating the radio conditions of the cells at the
frequency at which the event occurred and at the other different frequency.

[Claim 3]
The terminal apparatus according to claim 1, wherein
the measurement report creating section creates the
measurement report including information about the
received quality of radio waves from the cell if the
handover control is to be performed on the basis of both
of the measurement reports at the frequency at which the
event occurred and at the other frequency; and
creates the measurement report including information
about the received power of the radio waves from the cell
if the handover control is to be performed on the basis
of only the frequency at which the event occurred.

[Claim 4]
The terminal apparatus according to claim 1,
comprising a judgment section that judges whether or not to create the measurement report including the
information indicating the radio conditions of the cells at the frequency at which the event occurred and at the other different frequency.

[Claim 5]

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The terminal apparatus according to claim 2, wherein
a policy for deciding a cell to be selected as a
candidate for performing handover, among the multiple
cells, is set in the terminal apparatus; and
the measurement report creating section selects a
measurement report of a cell selected as a candidate on
the basis of the policy, among measurement reports of the
multiple cells, as the information indicating the radio
conditions of the cells at the frequency at which the
event occurred and at the other different frequency.

[Claim 6]
The terminal apparatus according to any of claims 2 to 5, wherein the measurement report creating section selects a measurement report of the radio condition of a cell judged to have a higher communication quality in comparison with a predetermined reference quality set at the frequency at which the event occurred.

[Claim 7]
The terminal apparatus according to claim 2, wherein
the measurement report creating section selects a
measurement report of the radio condition of a cell
judged to have a higher communication quality in
comparison with a predetermined reference quality set at
each of the frequencies used for the communication.

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[Claim 8]
The terminal apparatus according to claim 2, wherein
a priority degree at the time of performing handover
is set for each of the multiple frequencies, in the
terminal apparatus; and
the measurement report creating section selects a
measurement report of a frequency selected on the basis
of the priority degree, among the measurement reports of
the cells at the multiple frequencies, as the information
indicating the radio condition of the cell at the other
frequency.

[Claim 9]
The terminal apparatus according to claim 1, the
terminal apparatus being communicable with one base
station apparatus by band aggregation in which multiple carrier frequencies are used, in the wireless
communication system.

[Claim 10]
The terminal apparatus according to claim 1, wherein measurement results of multiple frequencies are collected in one measurement report.

[Claim 11]
The terminal apparatus according to claim 1, wherein
the measurement report includes a measurement result of

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the cell at which the event occurred and a measurement
result of a cell paired with the cell at which the event occurred.

[Claim 12]
The terminal apparatus according to claim 1, wherein
the measurement report includes all measurement results
of multiple serving cells or measurement results of a
part of serving cells selected from among the multiple
serving cells.

[Claim 13]
A wireless communication system in which a base
station apparatus and the terminal apparatus are
communicable with each other using multiple frequencies, wherein
the terminal apparatus comprises:
an event detecting section that detects occurrence
of an event for transmitting a measurement report of a
radio condition of a cell at a frequency set for the base station apparatus, to the base station communicating with the terminal apparatus; and
a measurement report creating section that creates the measurement report including information indicating radio conditions of the cells at a frequency at which the event occurred and at another different frequency, on the basis of occurrence of the event; and

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the base station apparatus comprises:
a handover control section that controls whether or not to perform handover to the cell of the terminal
apparatus on the basis of the measurement report
transmitted from the terminal apparatus.

[Claim 14]
A base station apparatus used in a wireless
communication system in which the base station apparatus and a terminal apparatus are communicable with each other using multiple frequencies;
the terminal apparatus creating the measurement
report including information indicating radio conditions
of cells at a frequency at which the event occurred and
at another different frequency, on the basis of
occurrence of an event for transmitting a measurement
report of a radio condition of a cell at a frequency set
for the base station apparatus, to the base station
communicating with the terminal apparatus; and
the base station apparatus comprising a handover
control section that controls whether or not to perform
handover to the cell of the terminal apparatus on the
basis of the measurement report transmitted from the
terminal apparatus.

[Claim 15]

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A wireless communication method used in a wireless
communication system in which a base station apparatus
and the terminal apparatus are communicable with each
other using multiple frequencies, the method comprising:
the terminal apparatus detecting occurrence of an
event for transmitting a measurement report of a radio
condition of a cell at a frequency set for the base
station apparatus, to the base station communicating with
the terminal apparatus;
the terminal apparatus creating the measurement
report including information indicating radio conditions of the cells at a frequency at which the event occurred and at another different frequency, on the basis of
occurrence of the event; and
the base station apparatus controlling whether or not to perform handover to the cell of the terminal apparatus on the basis of the measurement report
transmitted from the terminal apparatus.