Technical Field
[0001]
10 The present disclosure relates to a communication control apparatus, a
communication control method, a radio communication system and a terminal
apparatus.
Background Art
15 [0002]
In long term evolution (LTE) that is a cellular communication scheme
standardized in the third generation partnership project (3GPP), as a bandwidth used
for radio communication, 6 alternatives of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15
MHz and 20 MHz are defined (see, for example, Non-Patent Literature 1). In LTE-
20 advanced (LTE-A) obtained by developing the LTE, technology called carrier
aggregation is further introduced, which allows a plurality of componc~lt carriers
each having any bandwidth described above to be integrally used. For example,
when the two componeilt carriers each having a bandwidth of 20 MHz are
simultaneously used, it is possible to form a radio channel of 40 MHz in total.
25 [0003]
However, frequency bands assigned to communication providers in each
country are not always adapted to the bandwidths defined in the LTE (hereinafter, a
term of the LTE also includes the LTE-A). here fore, when the communication
providers operate an LTE system, an excess frequency bald may remain as it is
30 without being used. Then, a concept called band-filling has been proposed, in
which an extension band is set to the excess frequency band adjacent to the
component carrier, and the extension band is also used for radio communication, in
order to improve utilization efficiency of frequency resources (see, for example,
Non-Patent Literature 2).
5 Citation List
Non-Patent Literature
[0004]
Non-Patent Literature 1: 3GPP, "3GPP TS 36.104 V11.4.0", March 22,
2013
10 Non-Patent Literature2: AT&T, "NCT and Band Filling", R1-130665,
3GPP TSG RAN WGl Meeting #728, January 28-Fcbruary 1,2013
Summary of Invention
Technical Problem
15 [0005]
However, if the communication providers can freely set the extension band
to the excess frequency band, various problems such as complication of
implementation, an increase in overhead, deterioration in communication quality and
a loss of backward compatibility may be caused.
20 [0006]
Therefore, it is desirable to provide a system capable of utilizing the
extension band efficiently by solving or reducing at least one of the problems
assumed related to the band-filling.
25 Solution to Problem
[0007]
According to the present disclosure, there is provided a communication
control apparatus including: a communication control unit that controls radio
communication performed by one or more terminal apparatuses on a component
30 canier having a basic bandwidth. The communication control unit sets an extension
band to bc added to the component carrier only to an excess frequency band either on
an upper side or a lower side of the component carrier.
[OOOS]
According to the prescnt disclosure, there is provided a communication
control method including: controlling radio communication performed by one or
5 more terminal apparatuses on a component carrier having a basic bandwidth; and
setting an extension band to be added to the component carrier only to an excess
frequency band either on an upper side or a lower side of the component carrier.
[0009]
According to the present disclosure, there is provided a radio
10 communication system including: one or more terminal apparatuses; and a
communication control apparatus. The communication control apparatus sets an
extension band to be added to the component carrier only to an excess frequency
band either on an upper side or a lower side of the component carrier having a basic
bandwidth. At least one of the terminal apparatuses executes radio communication
15 on the extension band.
[OOlOl
According to the present disclosure, there is provided a terminal apparatus
including: a radio communication unit that communicates with a communication
control apparatus controlling radio communication performed on a component carrier
20 having a basic bandwidth, the communication control apparatus setting an extension
band to be added to the component carrier only to an excess frequency band either on
an upper side or a lower side of the component carrier; and a control unit that, when
the extension band is set by the communication control apparatus, allows the radio
communication unit to execute the radio communication on the set extension band.
25
Advantageous Effects of Invention
[OOll]
According to thc technology according to the present disclosure, it is
possible to utilize the extension band in the band-filling efficiently.
30
Brief Description of Drawings
[0012]
[FIG. 11 FIG. 1 is an explanatory diagram for explaining an outline of an LTE system.
[FIG. 21 FIG. 2 is an explanatory diagram for explaining an example of a
configuration of a downlinlc resource.
5 [FIG. 31 FIG. 3 is an explanatory diagram for explaining an example of a
configuration of an uplink resource.
[FIG. 4A] FIG. 4A is an explanatory diagram for explaining a first example of an
arrangement of a component carrier in a frequency domain.
[FIG. 4B] FIG. 4B is an explanatory diagram for explaining a second example of an
10 arrangement of a component carrier in a frequency domain.
[FIG. 4C] FIG. 4C is an explanatory diagram for explaining a third example of an
arrangement of a component carrier in a frequency domain
[FIG. SA] FIG. SA is an explanatory diagram illustrating an example of an extension
band set on one side.
15 [FIG. SB] FIG. 5B is an explanatory diagram for explaining the setting of the
extension band in a resource block unit, related to the example of FIG. SA.
[FIG. 6A] FIG. 6A is an explanatory diagram illustrating an example of the extension
band symmetrically set on both sides.
[FIG. 6B] FIG. 6B is an explanatory diagram for explaining the setting of the
20 extension band in the resource block unit, related to the example of FIG. 6A.
[FIG. 7A] FIG. 7A is an explanatory diagram illustrating an example of thc extension
band asymmetrically set on both sides.
[FIG. 7B] FIG. 7B is an explanatory diagram for explaining the setting of the
extension band in the resource block unit, related to the example of FIG. 7A.
25 [FIG. 81 FIG. 8 is an explanatory diagram for explaining an example of an
arrangement of a synchronization resource and a broadcast channel in the one-side
setting.
[FIG. 91 FIG. 9 is an explanatory diagram for explaining an exan~ple of an
arrangement of an uplink control channel in the one-side setting.
30 [FIG. 10A] FIG. 10A is an explanatory diagram for explaining a resource block
numbcr granted according to an existing method.
[FIG. 10B] FIG. 10B is an explanatory diagram for explaining a first example of a
new numbering rule of the resource block number.
[FIG. 1 OC] FIG. 10C is an explanatory diagram for explaining a second example of a
new numbering rule of the resource block number.
5 [FIG. 111 FIG. 11 is an explanatory diagram for explaining an example of band-filling
(BF) setting information assumed for the 3 setting patterns.
[FIG. 121 FIG. 12 is an explanatory diagram for explaining a first example of a
system for suppressing noise or interference.
[FIG. 131 FIG. 13 is an explanatory diagram for explaining a second example of the
10 system for suppressing noise or interference.
[FIG. 141 FIG. 14 is a block diagram illustrating an example of a configuration of a
base station according to an embodiment.
[FIG. 151 FIG. 15 is an explanatory diagram illustrating a setting example of an
extension band according to an embodiment.
15 [FIG. 161 FIG. 16 is a block diagram illustrating an example of a configuration of a
terminal apparatus according to an embodiment.
[FIG. 171 FIG. 17 is a block diagram illustrating an example of a detailed
configuration of a radio communication unit shown in FIG. 16.
[FIG. 181 FIG. 18 is a flow chart illustrating an example of a flow of band setting
20 processing according to an embodiment.
[FIG. 19A] FIG. 19A is a first half of a sequence diagram illustrating an cxample of a
flow of communication control processing according to an embodiment.
[FIG. 19B] FIG. 19B is a second half of the sequence diagram illustrating the
example of the flow of the communication control processing according to an
25 embodiment.
[FIG. 201 FIG. 20 is a flow chart illustrating an example of a flow of scheduling
processing according to an embodiment.
Description of Embodiments
30 [0013]
Hereinalter, preferred embodiments of the present invention will be
described in detail with reference to the appended drawings. Note that, in this
specification and the drawings, elements that have substantially the same function
and structure are denoted with the same reference indicators, and repeated
explanation is omitted.
5 [0014]
Furthermore, description will be provided in the following order.
1. Outline of system
1-1. Nodes constituting system
1-2. Configuration of resource
10 1-3. Band-filling
1-4. Various settings of extension band
1-5. Arrangement of main channels
1-6. Identification of resource
1-7. Suppression in noise or interference
15 3. Configuration example of base station
4. Configuration example of terminal apparatus
5. Flow of processing
5-1. Band setting processing
5-2. Conmunication control processing
20 5-3. Scheduling processing
6. Summary
[00 151
4. Outline of system>
First, using FIG. 1 to FIG. 3, an outline oCan LTTE system will be described.
25 [0016]
[I-1. Nodes constituting system]
FIG. 1 is an explanatory diagram lor explaining the outline of the LTE
system. With reference to FIG. 1, an LTE system 1 includes one or more base
stations 10, one or more terminal apparatuses 12, and a core network (CN) 16.
30 [0017]
The base station 10 is a communication control apparatus also called an
evolved node B (eNB) in the LTE. The base station 10 provides radio
communication service for the terminal apparatus 12 positioned within a cell 11.
The base station 10 is connected to the core network 16. The terminal apparatus 12
is a radio communication apparatus also called as user equipment (UE) in the LTE.
5 The terminal apparatus 12 is connected to the base station 10, and performs radio
communication. The base station being currently connected by the terminal
apparatus 12 is called a serving base station of the terminal apparatus 12. The
serving base station executes various control such as scheduling, rate control,
resending control and transmission power control for the individual terminal
10 apparatuses 12. The core network 16 is also called an evolved packet core (EPC) in
the LTE, and includcs various control nodes such as a mobility management entity
(MME), a PDN-gateway (P-GW) and a serving-gateway (S-GW) (not shown). The
MME manages mobility of the terminal apparatus 12. The S-GW is a gateway
transferring a packet of a user plane for the terminal apparatus 12. The P-GW is a
15 gateway positioned at a connection point between the core network 16 and a packet
data network (PDN) 17. The PDN 17 may include an IP network such as the
Internet and an enterprise network.
[00 181
[I-2.C onfiguration of resource]
20 A radio link from the base station 10 to the terminal apparatus 12 is a
downlink (DL). A ~adioli nk from the terminal apparatus 12 to the base slation 10 is
an uplink (UL). In the LTE, a group of frequency bands including various control
channels and data channels defined to realize the radio communication service are
called a component carrier. When the LTE system operates on a frequency division
25 duplex (FDD) scheme, the component carrier in the downlink (downlink CC) and the
component carrier in the uplink (uplink CC) are separate frequency bands. When
the LTTE system operates on a time division duplex (TDD) scheme, both downlink
transmission and uplink transmission are performed on the one component carrier.
[0019]
30 FIG. 2 is an explanatory diagram for explaining an example of a
configuration of a downlink resource. In an upper part of FIG. 2, one radio frame
having the length of 10 msec is shown. The one radio frame includes 10 subframes
each having the lcngth of 1 msec. The one sub-frame includes two 0.5 ms
slots. The one 0.5 ms slot normally includes 7 OFDM symbols (6 OFDM symbols
when an extension cyclic prefix is used) in a time direction. Then, the one OFDM
5 symbol and 12 subcarriers in a frequency direction constitute one resource block.
In 6 resource blocks positioned on the center of the component carrier in the
frequency direction among such time-frequency resources, a resource and a
broadcast channel (BCH) for transmitting a synchronization signal are arranged. In
this specification, the resource for transmitting the synchronization signal is called a
10 synchronization resource. The terminal apparatus receives a primary
synchronization signal and a secondary synchronization signal on the
synchronization resource in order to establish synchronization with the base station
in a cell search procedure. The broadcast channel is used for broadcasting a master
information block (MIB). The MIB conveys static broadcast information such as a
15 bandwidth of the component carrier and the number of antennas of the base station.
Note that dynamic broadcast information is conveyed by a system information block
(SIB) on a downlink shared channel (DL-SCH). The remaining resource blocks
may be used for data transmission in the downlink.
[0020]
20 FIG. 3 is an explanatory diagram for explaining an example of a
configuration of an uplink resource. Also in the uplink, one radio frame ~ncludes 10
sub-frames each having the length of 1 msec. The one sub-frame includes 2 0.5 ms
slots. In the center in the time direction of each of the 0.5 ms slots, a reference
sequence used by the base station for demodulating an uplinlc signal is arranged. A
25 random access channel (PRACH) is used by the terminal apparatus for transmitting a
random access signal (random access preamble) lo the base station. The terminal
apparatus acquires which of the lesource blocks the random access channel is
assigned to by receiving the SIB (more specifically, SIB2 of SIB1 to SIB 8). A
physical uplink control charnel (PUCCI-I) is used by the terminal apparatus for
30 transmitting an uplink control signal. A physical uplink sharcd channel (PUSCH) is
used by the terminal apparatus for transmitting an uplink data signal. The PUCCH
is arranged in a band end of the component carrier for allowing more continuous
resource blocks to be assigned to the terminal apparatus on the PUSCH. This
prevents a peak-to-average power ratio (PAPR) of the uplink data signal from
increasing to deteriorate power efliciency.
5 [0021]
Note that, also in the LTE of the TDD scheme, one radio frame includes 10
sub-frames each having the length of 1 msec. However, some of the 10 sub-frames
are downlink sub-frames, and some other sub-frames are uplink sub-frames.
[0022]
10 The base station controls radio communication performed by the terminal
apparatus in a resource block unit for both of the downlink resource and the uplink
resource. This is applied not only to the FDD but to the TDD. For example,
resource assignment information transmitted from the base station to the terminal
apparatus identifies the resource block to be assigned by using a unique resourcc
15 block number in a frequency domain. In this specification, the resource assignment
information may include scheduling information indicating resource assignment (DL
assignment and UL grant) for data transmission, and channel arrangerncnt
information indicating an arrangement of the control channels. The channel
arrangement information is, for example, information for indicating the arrangement
20 of the PRACH described above to the terminal apparatus.
[0023]
[I-3. Band filling]
The table 5.6-1 of Nan-Patent Literature 1 defines 6 alternatives of the
bandwidth of the component carrier in the LTE. According to the definition, the
25 bandwidths of the component canier include 1.4 MHz, 3 MI-Iz, 5 MHz, 10 MHz, 15
MHz and 20 MHz. These bandwidths are called a basic bandwidth in this
specification. However, frequency bands assigned to communication providers in
each country are not always adapted to these basic bandwidths.
[0024]
30 FIG. 4A is an explanatory diagram for explaining a first example or the
arrangement of the component ca~i-ieri n the frequency domain. Ln the first example,
a frequency band of 4 MIIz can be used for a provider. Note that, for convenience
of the description, only one link direction is considered. When the provider sets a
component carrier CO having the basic bandwidth of 3 MHz to the frequency band
that can be used, an excess band having a bandwidth of 1 MHz remains. However,
5 since the bandwidth of 1 MHz is less than any basic bandwidth, this excess hand is
not utilized.
[0025]
FIG. 4B is an explanatory diagram for explaining a second example of the
arrangement of the component carrier in the frequency domain. In the second
10 example, a frequency band of 12 MHz can be used for a provider. When the
provider sets component carriers C11, C12, C13 and C14 each having the basic
bandwidth of 3 MHz to the frequency band that can be used, and applies carrier
aggregation to these component carriers, an excess band is not generated. This
solution seemingly appears to be optimal in terms of utilization efficiency of the
15 frequency resource. However, all the terminal apparatuses do not support the
carrier aggregation, and the terminal apparatus that does not support the carrier
aggregation can use only the one component carrier. Therefore, the solution of FIG.
4B practically includes a waste of the resource (the terminal apparatus that does not
support the carrier aggregation cannot use a bandwidth of 9 MI-Iz). Therefore, the
20 provider may hope to set the single component carrier having the wider basic
bandwidth, Furthel; since the carrier aggregation in the LTE-A has a reslriction that
intervals between the center frequencies of the multiple CCs must be the integer
multiple of 300 kHz, an optimal arrangement of the component carrier may be
realized only in a limited case.
25 [0026]
FIG. 4C is an explanatory diagram for explaining a third example of the
arrangement of the component carricr in the frequency domain. Also in the third
example, the frequency band of 12 MHz can be used for a providcr. Unlike the
second example, when the provider sets a component carrier C10 having the basic
30 bandwidth of 10 MHz, the terminal apparatus can usc the component carrier CIO
regardless of whether it supports the carrier aggregation. However, with the
solution of FIG. 4C, an excess band having a bandwidth of 2 MHz remains.
[0027]
The band-filling is a concept for utilizing the excess frequency band as
exemplified in FIG. 4A and FIG. 4C as the extension band for extending the
5 bandwidth of the component carrier. However, there are some problems in the
band-filling.
[0028]
(1) Overhead of control signal
A bandwidth of the excess frequency band is normally assumed to be
10 smaller than the basic bandwidth. Therefore, when a control resource (for example,
a synchronization resource, a broadcast channel and other channels for a control
signal) for allowing the terminal apparatus to use the extension band is arranged in
the extension band, a rate of overhead of the resource for the control signal is
relatively increased.
15 [0029]
(2) Notification of extension bandwidth
When the component carrier and the extension band added to the component
carrier are handled as one frequency band, the total bandwidth does not correspond
to the specified 6 basic bandwidths in most cases. On the other hand, bandwidth
20 information broadcasted to the terminal apparatus in the existing MIB can only
indicate any of the 6 basic bandwidths. Modification of the bandwidth information
hinders a normal operation of the terminal apparatus that does not support radio
communication on the extension band (hereinafter, referred to as a legacy terminal).
Therefore, it is desirable to introduce a new information element for notifying the
25 terminal apparatus of a bandwidth of the extension band (hereinafter, referred to as
an extension bandwidth) without modifying the bandwidth information for the basic
bandwidth in the MIB. However, if the extension bandwidth can take any value,
the number of bits of the new information element may increase excessively.
[0030]
30 (3) Compatibility with legacy terminal
As described above, the resource assignment information transmitted from
the base station to the terminal apparatus identifies the individual resources in the
resource block unit. Normally, the resource block numbers are granted to the
resource blocks in the increasing order of the frequency. However, when thc
resource block numbers smaller than those of the component carrier are granted to
5 the resourceblocks in the extension band in the case where the extension band is set
to a lower side (a lower side of the frequency) of the component carrier, the legacy
terminal may misunderstand that the resource block numbers point to the resource
blocks in the component carrier.
[003 11
10 (4) Complexity of transmitter-receiver
Since there are only 6 alternatives of the basic bandwidth in the LTE, a
transmitter-receiver as an apparatus receiving radio signals of the LTE only may be
designed so as to handle the 6 basic bandwidths. Specifically, circuit parameters
such as a sampling rate, a cut-off frequency of a low-pass filter and a fast Fourier
15 transform (FFT) size may depend on a transmitting and receiving band (and a
bandwidth thereof). However, when the extension bandwidth is set to any value,
the transmitter-receiver will be required to be designed so as to correctly operate for
every setting value of the extension band, resulting in a remarkable increase in
implementation cost of the apparatus.
20 [0032]
(5) Deterioration in rcception quality of legacy terminal
When the extension band is set to the excess frequency band adjacent to the
downlink CC, the legacy terminal recognizes a. signal received on the extension band
as noise. The low-pass filter of the transmitter-receiver of the legacy terminal
25 cannot thoroughly remove this noise received at a frequency close to that of a desired
signal. Therefore, the transmission of the radio signal on the extension band may
deteriorate reception quality in the legacy terminal.
[0033]
(6) Time of cell search
30 According to the procedure of the existing cell search, the terminal
apparatus can detect the synchronization signal by using as a clue the fact that the
synchronization signal is transmitted in the band center of the downlink CC.
However, when the extension band is set, the synchronization signal does not always
exist in the center of the band including the downlink CC and the extension band.
If the position of the synchronization signal is unclcar, the terminal apparatus cannot
5 help searching for the synchronization signal blindly to elongate a time before it is
detected.
[0034]
(7) Interference caused by extension band
Wben a radio signal is transmitted on the extension band in a certain cell,
10 the radio signal may cause inter-cell interference in adjacent cells. The hase station
in the LTE has a system called inter-cell interference coordination (ICIC) for
suppressing the inter-cell interference, but since the current ICIC is not designed in
consideration of the band-filling, it is beneficial to introduce an additional system for
suppressing the inter-cell interference caused by the extension band.
15 [0035]
(8) Discontinuity of uplink resource
As described above, the PUCCH used by the terminal apparatus to transmit
the uplink control signal is arranged in the band end of the component carrier in
order to make it possible to assign more continuous resourcc blocks to the terminal
20 apparatus on the PUSCH. However, when the extcnsion band is set to the outside
of the band of the cotnponent carrier, the PUSCH of the component catrlcr and the
channel in the extension band become discontinuous across the PUCCH.
[0036]
The technology according to the present disclosure is provided for solving
!;
i 25 or reducing at least one of the problems assumed related to the band-filling as
.$
:; described here.
[0037]
[I-4. Setting patterns of extension band]
FIG. 5A to FIG. 5C are explanatory diagrams illustrating 3 setting patterns of
I 30 the extension band, respectively. These setting patterns are distinguished by a
positional relationship between the component carrier and the extension band added
to the component carrier. A first setting pattern is one-side setting, a second setting
pattern is both-side symmetric setting, and a third setting pattern is both-side
asymmetric setting.
[0038]
5 (1) One-side setting
FIG. 5A illustrates an example of the one-side setting. According to the
one-side setting, the extension band is added to the component carrier only in the
excess frequency hand on either ibe upper side or the lower side of the component
carrier. With reference to FIG. 5A, a downlink CC DCll and an uplink CC UC14
10 are arranged in a band from a frequency F11 to a frequency F12 and in a hand from a
frequency F15 to a frequency F16, respectively. An extension band EB13 is an
extension band added to the downlink CC DC11. The extension band EB13
occupies a band from a frequency F13 to a frequency F14 on the upper side of the
downlink CC DC11. An extension band EB15 is an extension band added to the
15 uplink CC UC14. The extension band EB15 occupies a band from a frequency F16
to a frequency F17 on ihe upper side of the uplink CC UC14.
[0039]
A gap between the upper end frequency F12 of the downlink CC DC11 and
the lower end frequency F13 of the extension hand EB13 is used as a guard hand
20 GB12. In the guard hand, a radio signal is not transmitted. As a result of the
arrangement of such a guard band, the transmitter-receiver of the legacy Lcrtninal can
suppress the noise or interference caused by the radio signal on the extension band,
for example, by using a filter. Note that, since the guard band is a band that is not
used for transmission of the radio signal, the arrangement of the guard band has a
25 negative effect in terms of resource utilization efficiency. I-Iowever, according to
the one-side setting as exemplified in FIG. 5A, it is enough to aiyange only the one
guard hand on cither the upper side or the lower side of the downlink CC.
'Therefore, it can be said that the one-side setting is an effective setting pattern
realizing an appropriate balance between the avoidance of deterioration in reception
30 quality of the legacy terminal and the resource utilization efficiency. Further, the
one-side setting is also a setting pattern allowing more continuous shared channels to
be arranged in the extension band in the uplink, compared with the both-side setting
to be described later. Since the base station receiving the uplink signal knows the
cxistence of the extension band, the guard band may not be arranged between the
uplink CC UC14 and the extension band EBI 5.
5 [0040]
In a certain embodiment, the extension band is set so as to have the
extension bandwidth of the integer multiple of the size of the resource bloclc. As
described above, one resource block has 12 subcarriers in the frequency direction.
Since the subcarriers are arranged at frequency intervals of 15 kHz, the size of the
10 one resource bloclc in the frequency direction (hereinafter, referred to as an RB size)
is 180 kHz. With reference to the example of FIG. 5B, the extension band EB13
occupies 6 resource bloclcs in the frequency direction (F14-F13=6~180=1080 [kHz]).
The guard band GB12 occupies 2 resource blocks in the frequency direction
(F13-F12=2x 180=360 [kHz]). The extension band EB15 occupies 8 resource
15 blocks in the frequency direction (F17-F16=8x 180=1440 [kHz]).
[0041]
The arrangement of the extension band in the resource block unit in this
manner allows the extension band to be expressed by the number of the resource
bloclts. This makes it possible to notify the terminal apparatus of the extension
20 band with a small number of bits by using an index based on the number of the
resource blocks (for example, the number of the resource blocks itsclf, a code
mapped to the number of the resource blocks, or any value calculated from the
number of the resource bloclts).
[0042]
i
j 25 The guard band may be arranged in the resource block unit (that is, so as to
.I
have the bandwidth of the integer multiple of the RB size), or may be arranged, for
example, in a subcarrier unit (that is, so as to have the bandwidth of the integer '1 multiple of 15 1tIIz). The terminal apparatus may be explicitly notified of the
i setting of the guard band. Instead, the notification of the setting of the guard band
I 30 may be omitted by, for example, specifying the bandwidth in advance. Further,
when the guard band is arranged in the resource block unit, the bandwidth of the
guard band may be a part of the extension bandwidth reported to the terminal
apparatus. In this case, even when the bandwidth of the guard band is not explicitly
reported, for example, when the base station does not schedule the downlink
transmission on the guard band, it is possible to substantially realize the guard band
5 without making the terminal apparatus notice the existence of the guard band. This
can reduce overhead of information required for the notification of the guard band,
and makes it easy for the base station to dynamically change the bandwidth of the
guard band.
[0043]
10 (2) Both-side symmetric setting
FIG. 6A illustrates an example of the both-side symmetric setting.
According to the both-side symmetric setting, the extension bands are symmetrically
added to the component carrier in the excess frequency bands on the upper side and
the lowcr side of the component carrier. With reference to FIG. 6A, a downlink CC
15 DC23 and an uplink CC UC27 are arranged in a band from a frequency F22 to a
frequency F23 and in a band from a frequency F27 to frequency F28, respectively.
An extension band EB21 is a lower-side extension band added to the downlink CC
DC23. The extension band EB21 occupies a band from a frequency F20 to a
frequency F21. A guard band GB 22 is arranged between the extension band EB21
20 and the downlink CC DC23. An extension band EB25 is an upper-side extension
band added to the downlink CC DC23. The extension band EB25 occupies a band
from a frequency F24 to a frequency F25. A guard band GB 24 is arranged between
the downlink CC DC23 and the extension band EB25. An extension band EB26 is
a lower-side extension band added to the uplink CC UC27. The extension band
25 EB26 occupies a band from a frequency F26 to a frequency F27. An extension
band EB28 is an upper-side extension band added to the uplink CC UC27. The
extension band EB28 occupies a band from a frequency F28 to a frequency F29. In
the uplink, the guard band may not be arranged.
[0044]
30 In a certain embodiment, the extension band is set so as to have the
extension bandwidth of the integer multiple of the size of the resource block. With
reference to the example of FIG. 6B, the extension bands EB21 and EB25 occupy 6
resource blocks in the frequency direction. The guard bands GB22 and G24 occupy
2 resource blocks in the frequency direction. The extension bands EB26 and EB28
occupy 8 resource blocks in the frequency direction. When the extension bloclts are
5 arranged in the resource block unit in this manner, it is possible to express the
extension bandwidth by the number of the resource blocks. This makes it possible
to notify the terminal apparatus of the extension bandwidth with a small number of
bits by using the index based on the number of the resource blocks. In the both-end
symmetric setting, since the extension bands on both sides of the component carrier
10 have the same extension bandwidth, it is enough for the terminal apparatus to be
notified of only information on one extension bandwidth for the two extension bands.
100451
The guard bands may be symmetrically arranged in the resource block unit,
or may he symmetrically arranged in the subcarrier unit. The terminal apparatus
15 may be explicitly notified of ihe setting of the guard hands, or may not be notified of
the setting of the guard bands. Further, in the case where the guard bands are
arranged in the resource block unit, when the terminal apparatus is not explicitly
notified of the bandwidth of the guard band, and, for example, when the base station
does not schedule the downlink transmission on the guard band, the guard band may
20 be substantially realized. This can reduce the overhead of the information required
for the notification or the guard band, and can make it easy for the base station to
dynamically change the bandwidth of the guard band.
I [0046]
!
4 (3) Both-side asymmetric setting :j 25 FIG. 7A illustrates an example of the both-side asymmetric setting.
According to the both-side asymmetric setting, the extension bands are
asymn~etricallya dded to the component carrier in the excess frequency bands on the
upper side and the lower side of the component carrier. With reference to FIG. 7A,
a downlink CC DC33 and an uplink CC UC37 are aranged in a band from a
30 frequency F32 to a frequency F33 and in a band from a frequency F37 to frequency
F38, respectively. An extension band EB21 is a lower-side extension band added to
the downlink CC DC33. The extension band EB31 occupies a band from a
frequency F30 to a frequency F31. A guard band GB 32 is arranged between the
extension band EB31 and the downlink CC DC33. An extension band EB35 is an
upper-side extension band added to the downlink CC DC33. The extension band
5 EB35 occupies a band from a frequency F34 to a frequency F35. A guard band GB
34 is arranged between the downlink CC DC33 and the extension band EB35. An
extension band EB36 is a lower-side extension band added to the uplink CC UC37.
The extension band EB36 occupies a band from a frequency F36 to a frequency F37.
An extension band EB38 is an upper-side extension band added to the uplink CC
10 UC37. The extension band EB38 occupies a band fiom a frequency F38 to a
frequency F39. In the uplink, the guard band may not be arranged.
[0047]
Also in the both-side asymmetric setting, when a radio signal is not
transmitted in the guard band between the downlink CC and the two extension bands,
15 it is possible to suppress noise or interference in a reception circuit of the legacy
terminal to avoid deterioration in reception quality. Further, the both-side
asymmetric setting has an effect being more advantageous than the one-side setting
described above in terms of a cell search procedure to be described later.
[0048]
20 In a certain embodiment, the extension band is set so as to have the
extension bandwidtli of the integer multiple of the size of the resourcc block. With
reference to the example of FIG. 7B, the extension band EB3 1 occupies 4 resource
blocks in the frequency direction. The guard bands GB32 and GB34 occupy 2
resource blocks in the frequency direction. The extension bands EB35 occupies 8
25 resource blocks in the frequency direction. The cxtension bands EB36 occupies 6
resource blocks in the frequency direction. The extension bands EB38 occupies 10
i resource blocks in the frequency direction. When the extension blocks are arranged
in the resource block unit in this manner, it is possible to express the extension
bandwidth by the number of the resource bloclts. This makes it possible to notify
30 the terminal apparatus of the extension bandwidth with a small number of bits by
using the index based on the number of the resource blocks. Also in the both-end
asymmetric setting, when the terminal apparatus is not explicitly notified of the
bandwidth of the guard band, the overhead of the information required for the
notification of the guard band may be reduced.
[0049]
When these setting patterns are compared with each other, it can be said that
the one-side setting is the best in terms of the utilization efficiency of the resource,
the reduction in the overhead, and the continuity of the uplink resource. Then, in an
embodiment to be described later, the one-side setting is adopted as the setting
pattern of the extension band.
[0050]
[I-5. Arrangement of main channels]
(1) Downlink
Even when any setting pattern is selected, by using the synchronization
resource of the component carrier for allowing the terminal apparatus to be
synchronized with the extension band, it is possible to avoid an increase in overhead
of the resource required for transmission of the synchronization signal. In this case,
the base station operates the component carrier and the extension band added to the
component carrier in time synchronization with each other. Further, control
information such as the broadcast information referred to by the terminal apparatus
to use the extension band may be also transmitted on the component carrier instead
of the extension band
[0051]
FIG. 8 is an explanatory diagram for explaining an example of an
arrangement of the synchronization resource and the broadcast channel in the oneside
setting. With reference to FIG. 8, the downlink CC DCll and the extension
band EBl3 on the upper side of the downlink CC DCI1 are shown. In 6 resource
bloclts in the center of the downlink CC DC11, the synchronization resource for
transmitting the primary synchronization signal and the secondaiy synchronization
signal is arranged. This synchronization resource of the downlink CC DC11 is used
also for allowing the terminal apparatus to be synchronized with the extension band
EB13. In this manner, when the synchronization resource is used in common
between the component carrier and the extension band, both of the legacy terminal
and a non-legacy terminal will have only to search for the synchronization signal on
the synchronization resource of the component carrier in the procedure of the cell
search. Therefore, without modifying implementation of the procedure of the
existing cell search, it is possible to implement the non-legacy terminal. Further,
even when the extension bandwidth is less than the minimum basic bandwidth, it is
possible to allow the terminal apparatus to be appropriately synchronized with the
extension band by using the synchronization resource arranged in the component
carrier instead of the extension band.
[0052]
In the resource blocks positioned at the same frequency as that of the
synchronization resource, a physical broadcast channel (PBCH) for transmitting the
broadcast information is arranged. The PBCH is a physical channel corresponding
to the BCH. For example, band-filling (BF) setting information indicating the
extension bandwidth and the like may be broadcasted in the MIB on the PBCH.
Further, the BF setting information may be broadcasted in the SIB on the PDSCN.
Instead, the BF setting information may be transmitted to the individual terminal
apparatuses on the PDCCH. In this manner, the setting information related to the
extension band is transmitted on the downlink CC, the non-legacy terminal can
acquire the setting of the extension band by first establishing the synchronization
with the downlink CC, and then receiving the setting information on thc component
carrier. This makes it possible to smoothly transfer an operation from an operation
state in which the band-filling is not performed to an operation state in which the
band-filling is performed.
[0053]
Furthermore, scheduling information on the rcsource blocks in the extension
band, along with scheduling information on the resource blocks in the component
carrier, may be transmitted to the terminal apparatus on the PDCCH of the downlink
CC DCl1. This makes it possible to reduce overhead of the resource required for
30 transmission of the scheduling information. Further, acknowledge (ACK)lnegative
acknowledge (NACIC) to uplink transmission on the extension band in the uplink
may bc transmitted to the terminal apparatus on a physical hybrid-ARQ indicator
channel (PI-IICH) of the downlink CC DCll. When uplinlc transmission is
performed on the uplink CC and the extension band in the uplink, the ACK/NACK to
the uplink transmission may be processed and combined in the same HARQ
5 processes in the base station and transmitted to the terminal apparatus. This malces
it possible to reduce overhead of the resource required for transmission of the
ACWNACK.
[0054]
(2) Uplink
10 As described above, the PUCCH used by the terminal apparatus to transmit
the uplink control signal is arranged in the band end of the uplink CC. When the
terminal apparatus transmits the data signal, it is desirable to assign as many
continuous resource blocks as possible in the PUSCH to the terminal apparatus in
order to avoid the rise of the PAPR. However, if many of the resources in the
15 PUSCH for transmission of a control signal and a random access signal (hereinafter,
collectively referred to as a non-data signal) by the non-legacy terminal, it becomes
difficult to assign the continuous resource blocks in the PUSCH to the legacy
terminal that cannot use the extension band. Then, in a certain embodiment, the
transmission of the non-data signals in the uplink by the non-legacy terminal is
20 preferentially assigned to the extension band.
[0055]
FIG. 9 is an explanatory diagram for explaining an example of an
arrangement of the uplink control channel in the one-side setting. With reference to
FIG. 9, the uplink CC UC14 and the extension band EB15 on the upper side of the
25 uplink CC UC14 are shown. A physical uplink control channel (PUCCH) Chll is
arranged in the band end of the uplinlc CC UC14. A PUCCH Ch12 may be
arranged in the band end of the extension band EB15. The legacy terminal can use
only the uplink CC UC14. A physical random access channel (PRACH) Ch13 for
the legacy terminal is assigned to the resource blocks in the uplink CC UC14.
30 Therefore, the resource blocks of the PUSCH other than the PUCCH Chll and the
PRACH Ch13 in the uplink CC UC14 can be used for transmission of the data signal
by the lcgacy terminal. In the example of FIG. 9A, a separate PRACH Ch14 for the
non-legacy terminal is assigned to the resource blocks in the extension band EB15.
Accordingly, as many usable (and continuous) resource blocks as possiblc in the
PUSCH are left in the uplink CC UC14 for the legacy terminal.
5 [0056]
In this manner, when the PUCC and PRACH for the non-legacy terminal
(channels for the non-data signal) are preferentially assigned to the extension band in
the uplink instead of the uplink CC, it is possible for the legacy terminal to
successfully transmit the uplink data signal by using more continuous resource
10 blocks in the PUSCII. Further, when separate random access channels are prepared
in the legacy terminal and the non-legacy terminal, respectively, the possibility of
collision of the random access signal may be reduced to improve throughput of the
system.
[0057]
15 The legacy terminal may be notified of the arrangement of the PRACI-I for
the non-legacy terminal described using FIG. 9, separately from the channel
arrangement information on the arrangement of the PRACH for the legacy terminal,
conveyed on the SIB2. This new channel arrangement information may be
broadcasted using a new information element of the SIB in the downlink CC
20 exemplified in FIG. 8, or may be transmitted to the individual terminal apparatuses
$ on the PDCCH.
I;
Ij [0058]
;I Furthermore, the ACWNACK to downlink transmission on the downlink
;; CC and the extension band in the downlink may be processed and combined in the
;I :I
::I# 25 same HARQ processes in the terminal apparatus and transmitted to the base station.
:~I This makes it possible to reduce overhead of the resource required for transmission
of the ACKNACK. Note that the ACKNACK to the downlink transn~issionm ay
'1 be transmitted on the PUCCH or the PUSCH.
I
[0059]
30 [I-6. Identification of resources]
(1) Numbering rule
As described above, normally, in the resource assignment information
transmitted from the base station to the terminal apparatus, the individual resources
are identified by using the resource block numbers granted to the resource blocks in
the increasing order of the frequency. When the extension band is added to the
5 component carrier, it is desirable that the resource block number is unique through
the component carrier and the extension band. However, the extension band is set
to the band on the lower side of the component carrier, when the numbers are granted
to the resource blocks in the increasing order of the frequency, the numbers granted
to the resource blocks in the extension band on the lower side are set to be smaller
10 than the numbers grantcd to the resource blocks in the component carrier FIG. 10A
illustrates an example of such a situation. In the example of FIG. 10A, an extension
band EB41 includes 6 resource bloclcs having the resource bloclc numbers from "0"
to "5", respectively. A downlink CC DC43 includes 16 resource blocks having the
resource block numbers from "6" to "21", respectively. Note that the number of the
15 resource blocks in each of the component carrier and the extension band is merely an
example for description. Each band may include more resource blocks or less
resource blocks.
[0060]
According to the existing numbering rule exemplified in FIG. 10A, the
20 resource bloclc numbers granted to the resource blocks in the component carrier are
changed depending on the bandwidth of the extension band on the lowel side of the
component carrier. As a result, there is a possibility that the legacy terminal will
misunderstand that the small resource block numbers granted to the resource blocks
in the extension band EB41 point to the resource bloclcs in the component carrier
25 DC43. When the legacy terminal falsely interprets the resource block numbers,
radio cominunication by the legacy terminal would not operate correctly. Then, in a
certain embodiment, a number rule is adopted in which the resource block numbers
are uniquely granted to the respective resource bloclcs through the component carrier
and the extension band, and however, the resource bloclc numbers smaller than those
i
i 30 of the resource blocks included in the extension band are granted to any resource
!
blocks included in the component carrier. This makes it possible to solve the risk
that the legacy terminal misunderstands the meaning of the resource block numbers.
[0061]
FIG. 10B is an explanatory diagram for explaining a first example of the
new numbering rule of the resource block numbers. With refercnce to FIG. IOB,
5 similarly to FIG. 10A, the downlink CC DC43, and the extension band EB41 on the
lower side of the downlink CC DC43 are shown. A guard band GB42 exists
between the extension band EB41 and the downlink CC DC43. According to the
first example of the numbering rule, the resource block numbers are granted to the
one or more resource blocks in the downlinlc CC DC43 in the increasing order of the
10 frequency from zero. In the example of FIG, 10B, the resource block numbers from
"O" to "15" are granted to 16 resource blocks in the downlink CC DC43, respectively.
Further, the resource block numbers from "16" to "21" are granted to the resource
blocks in the extension band EB41, respectively. In the first example, the existence
of the guard band is not considered in the numbering of the resource block numbers.
15 [0062]
FIG. 10C is an explanatory diagram for explaining a second example of the
new numbering rule of the resource block number. Also in the second example of
the numbering rule, the resource block numbers are granted to the one or more
resource blocks in the downlink CC DC43 in the increasing order of the frequency
20 from zero. In the example of FIG, 10C, the resource block numbers from "O" to
"15" are granted to 16 resource blocks in the downlink CC DC43, tcspectively.
Further, the resource block numbers from "16" to "23" are granted to the resource
blocks in the extension band EB41 and the guard band GB42, respectively. The
second example of the numbering rule may be used, for example, in a case where the
25 terminal apparatus is not cxplicitly informed of the bandwidth of the guard band. In
this case, the terminal apparatus may recognize the resource blocks in the guard band
as a part of the extension band.
[0063]
In the first example and the second example of the numbering rule described
30 above, the legacy terminal identifies the resource blocks in the downlink CC DC43
by using the resource block numbers from "0" to. "15". These resource block
numbers are not changed depending on where or not the extension band is set, and
the bandwidth of the extension band. Therefore, it is possible to solve the risk that
the legacy terminal misunderstands the meaning of the resource block numbers, to
secure baclnvard compatibility.
[0064]
(2) BF setting information
FIG. 11 is an explanatory diagram for explaining an example of the BF
setting information assumed for the 3 setting patterns.. As described using FIG. 8,
the BF setting information is control information for notifying the non-legacy
terminal of the setting of the extension band. With reference to FIG. 11, the BF
setting information includes 6 data items of an "extension direction", a "bandwidth
I", a "bandwidth 2", a "guard bandwidth", and a "channel arrangement".
[0065]
The "extension direction" is a division identifying the setting pattern of the
extension band. As an example, a value "0" or ''1'' of the "extension direction"
indicates theone-side setting, and when the value is "O", the extension band is set on
the upper side of the component carrier, and when the value is "I", the extension
band is set on the lower side of the component carrier. A value "2" of the
"extension direction" indicates the both-side symmetric setting. A value "3" of the
"extension direction" indicates the both-side asymmetric setting. Note that, when
only the one-side setling can be selected as a restriction of the system, thc "extension
direction" may be a 1-bit flag indicating the value "0" or "1". When only the bothside
symmetric setting can be selected as the restriction of the system, the BF setting
information may not include the "extension direction" as an information element.
[0066]
The "bandwidth 1" indicates a bandwidth of a first extension band. The
''bandwidth 2" indicates a bandwidth of a second extension band. In the one-side
setting, the "bandwidth 2" is omitted. Also in the both-side symmetric setting, the
"bandwidth 2" is omitted, and two extension bands each having an extension
bandwidth indicated by the "bandwidth 1" are set on both sides of the component
ca~~ierI.n a certain embodiment, these "bandwidth 1" and "bandwidth 2" are an
index based on the number or the resource blocks corresponding to the extension
bandwidth. For example, when the extension bandwidth is 180 itHzxNku (NEB is an
integer of one or more), the "bandwidth 1" or the "bandwidth 2" can indicate NLU.
Instead, the "bandwidth 1" or the "bandwidth 2" may indicate a code mapped to NLU,
5 or any value calculated from NLD. Note that the BF setting information may include
the "extension direction", the "bandwidth 1" and the "bandwidth 2" for each of the
downlink and the uplink.
[0067]
The "guard bandwidth" indicates information indicating a bandwidth of the
10 guard band arranged between the downlink CC and the extension band. When the
bandwidth of the guard band equals to the integer multiple of the RB size, the "guard
bandwidth" may be an index based on the number of the resource blocks
corresponding to the guard bandwidth. Further, when the bandwidth of the guard
band equals to the integer multiple of the bandwidth for each subcarrier, the "guard
15 bandwidth" may he an index based on the number of the subcarriers corresponding to
the guard bandwidth. Note that, when the terminal apparatus is not explicitly
notified of the setting of the guard band, the BF setting information may not include
the "guard bandwidth" as an information element.
[0068]
20 The "channel arrangement" is channel information indicating an
arrangement of onc or more control channels for the non-legacy terminal. The
channel information may indicate, for example, an arrangement of the PUCCI-I and
the PRACH for the non-legacy terminal, arranged separately rrom the channels for
the legacy terminal. Note that, when the separate control channels are not arranged
25 for the non-legacy terminal, the BF setting information may not include such channel
arrangement inlormation.
[0069]
As understood from FIG. 11, when the one-side setting is adopted, the data
items of the BF setting information indicating the setting of the extension band are
30 less than when the both-side asymmetric setting is adopted, and in comparison with
the data items when the both-side symmetric setting is adopted, a 1-bit flag (the
I "extension direction" indicating the upper side or the lower side) is only added
[0070]
(3) Resource assignment information
In a certain embodiment, the base station transmits the resource assignment
5 information generated based on the resource block numbers granted to the respective
resource blocks according to the new numbering rule described above to the terminal
apparatus. The channel arrangement information described using FIG. 11 is an
example of the resource assignment information. Another example of the resource
assignment information is the scheduling information indicating the resource blocks
10 assigned to each terminal apparatus for data transmission.
[0071]
In an example of a specification of the LTE, the scheduling information
specifies a start number and the number of blocks of a set of the resource blocks to
be assigned to the terminal apparatus to identify the assigned resource blocks. In
15 such an information format, the non-legacy terminal is designed so as to handle a
start number exceeding the number of the resource blocks and the number of blocks
exceeding the number of the resource blocks. This allows the scheduling
information for the non-legacy terminal to identify the resource blocks included in
the extension band. For example, on the premise of the example of FIG. 10B, when
20 the scheduling information indicates a start number "16" and "the number of blocks"
2, the two resource blocks in the lower end of the extension band EB41 alc identified.
[0072]
In another example of the specification of the LTE, the scheduling
information identifies a set of the resource blocks to be assigned to the terminal
25 apparatus by a bitmap format. In such information format, the non-legacy terminal
1 is designed so as to handle a bitmap up to the resource block number larger than the
I
1 scheduling information to be transmitted to the legacy terminal. This allows the
i scheduling information for the non-legacy terminal to identify the resource blocks
I
i included in the extension band. For example, on the premise of the example of FIG.
30 10B, the scheduling information to be transmitted to the legacy terminal is generated
in a bitmap format of 16 bits in a case where the bitmap having the highest
granularity is selected. On the other hand, the scheduling information to be
transmitted to the non-legacy terminal is generated in a bitmap format of N bits
(N>16) in the same case. Note that, in any format, the scheduling information is
encoded using a terminal-specific identifier (ID) and is transmitted to each terminal
5 apparatus.
[0073]
In an example of the specification of the LTE, PRACH arrangement
information indicating the arrangement of the PRACH is included in the SIB2. The
PRACH is a physical channel used by the terminal apparatus to transmit the random
10 access preamble to the base station. The random access preamble is transmitted by
the terminal apparatus first connecting to the base station, the terminal apparatus
recovering from a sleep mode, or the terminal apparatus accessing the target base
station in a handover procedure, and, for example, is used to assume a timing offset
unique to the terminal apparatus. The PRACH arrangement information includes a
15 frequency offset indicating the arrangement in the frequency direction of the PRACH
(see, for example, "3GPP TS 36.211 V11.2.0", 3GPP, February, 2013). In a certain
embodiment, the base station assigns the PRACH for the non-legacy terminal to the
resource blocks in the extension band, separately from the PRACH for the legacy
terminal. The base station then generates the PRACH arrangement information
20 indicating the PRACH for the non-legacy terminal, separately from the PRACH
arrangement infornlalion for the legacy terminal. The PRACH arlangement
information for the non-legacy terminal may indicatc the frequency offset exceeding
the number of the resource blocks included in the uplink CC. The non-legacy
terminal is designed so as to handle such PRACH arrangement information for the
25 non-legacy terminal. This allows the PRACH arrangement information for the nonlegacy
terminal to identify the resource bloclts included in the extension band.
[0074]
Note that, without being limited by the description here, the channel
arrangement information indicating the arrangement of the channels other than the
30 PRACH may be generated based on the resource block numbers granted to the
respective resource blocks according to the new numbering rule described above.
[0075]
[I-7. Suppression of noise or interference]
In this section, an additional system for suppressing noise or interference
caused by the extension band will be described.
5 [0076]
FIG. 12 is an explanatory diagram for explaining a first example of the
system for suppressing noise or interference. In the first example, the component
carrier and the extension band to be added to the component carrier are set so as to be
overlapped with each other or so that the arrangement of the synchronization
10 resource is sifted between the adjacent cells. With reference to the exanlple of FIG.
12, while an extension band EB52 is set on the upper side of a downlink CC DC51 in
a cell C1, an extension band EB54 is set on the lower side of a downlink CC DC53 in
an acljacent cell C2 (that is, the positional relationship between the component carrier
and the extension band is reversed). The downlink CC DC51 has the
15 synchronization resource and the broadcast channel in a band from a center
frequency from F51 to F52 in the frequency direction. The downlink CC DC53 has
the synchronization resource and the broadcast channel in a band from a center
frequency from F53 to F54 in the frequency direction. As a result, the arrangement
of the synchronization resource and the broadcast channel is shifted between the
20 adjacent cells. Such non-uniform setting of the extension band over the multiple
cells can prevent the occurrence of the inter-cell inference in the synclrronization
resource and the main channels such as the broadcast channel to realize an stable
operation of the system.
[0077]
25 FIG. 13 is an explanatory diagram for explaining a second example of the
system for suppressing noise or interference. In the second example, the resource
blocks in the extension band in the downlink are assigned for downlink transmission
by the terminal apparatus closer to the center of the cell. With reference to FIG. 13,
a cell 1 la operated by a base station 1 Oa and a cell 11 b operated by a base station lob
30 are shown. The cells l l a and l l b are adjacent to each other. The terminal
apparatus 12a is the non-legacy terminal positioned inside a center region L1 of the
cell lla. The terminal apparatus 12b is the non-legacy terminal positioned around
the cell edge of the cell lla. The terminal apparatus 12c is the legacy terminal
positioned in the cell lla. The terminal apparatus 12d is the legacy terminal
positioned around the cell edge of the cell 1 lb. In such a situation, the base station
5 10a preferentially assigns the resource blocks in the extension band to the terminal
12a. Since a distance between the base station 10a and the terminal apparatus 12a
is relatively short, sufficient reception quality can be secured even with small
transmission power in downlink transmission to the terminal apparatus 12a. With
the small transmission power, the downlink transmission does not adversely affect
10 both of the legacy te~minal 12c in the serving cell l l a and the legacy terminal 12d in
the adjacent cell l l b (see arrows A1 and A2). On the other hand, the base station
10a preferentially assigns the resource blocks in the downlink CC to the terminal
apparatus 12b. Since a distance between the base station 10a and the terminal
apparatus 12b is relatively long, high transmission power may be required in
15 downlink transmission to the terminal apparatus 12b. With high transmission
power in the extension band, the legacy terminal may recognize the downlink
transmission on the extension band as noise or interference. However, when the
downlink transmission is performed not on the extension band but on the downlink
CC, it is possible to suppress the interference caused by the downlink transmission in
20 a general reception circuit, or control the interference by using an existing
interference control system such as a high interference indicator (HII).
[0078]
An exemplary embodiment of the basic station and the terminal apparatus
having some of the features described up to here will be described in detail from the
25 next section. Note that the features described above may be combined in any form
regardless of the exemplary embodiment.
[0079]
<3. Configuration example of base station>
In this section, an example of a configuration of a base station 100
30 according to an embodiment will be described. The base station 100 may bc a
macro cell base station or a small cell base station. A small cell is a concept
i
including a femto cell, a nano cell, a pic0 cell and a micro cell. Further, a part of a
function of the base station 100 described here may be implemented in the control
node in the core network 16 exemplified in FIG. 1.
FIG. 14 is a block diagram illustrating an example of the configuration of
the base station 100. With reference to FIG. 14, the base station 100 includes a
radio communication unit 110, a network communication unit 120, a storage unit 130
and a communication control unit 140.
[0081]
(1) Radio communication unit
The radio communication unit 11 0 is a radio communication interface (or a
radio transmitter-receiver) that executes radio communication with one or more
terminal apparatuses. The radio communication unit 110 transmits and receives a
radio signal on a frequency band set by the communication control unit 140 to be
described later. For example, the radio communication unit 110 transmits and
receives the radio signal to and from both of the legacy terminal and the hon-legacy
terminal on the component carrier having the basic bandwidth. Further, the radio
communication unit 110 transmits and receives the radio signal to and from the nonlegacy
terminal on the extension band added to the component carrier.
[0082]
Downlink signals transmitted by the radio communication unil 110 may
include a primary synchronization signal and a secondary synchronization signal, a
broadcast signal, a downlink control signal addressed to the individual terminals, and
a downlink data signal. The primary synchronization signal and the secondary
synchronization signal for allowing the terminal apparatus to be synchronized with
the component carrier are typically transmitted on the synchronization resource
arranged in 6 resource bloclts in the center of the con~ponent carrier. The radio
communication unit 110 then allows frame timing of the extension band to be
synchronized with frame timing of the component carrier. This allows the nonlegacy
terminal to receive the primary synchronization signal and the secondary
synchronization signal on the synchronization resource of the component carrier to
also establish synchronization with the extension band.
[0083]
The radio communication unit 110 may transmit the setting information
related to the extension band, including the BF setting inlormation described using
5 FIG. 11, not on the extension band but on the component carrier. For example, the
BF setting information may be broadcasted to the terminal apparatus in the MIB on
the PBCH or in the SIB on the PDSCH of the component carrier. Instead, the BF
setting information may be signaled to the individual terminal apparatuses on the
PDCCH of the component carrier.
10 [0084]
The radio communication unit 11 0 can transmit the scheduling information
related to the extension band (DL assignment and UL grant) not on the extension
band but on the PDCCH of the component carrier. This makes it possible to
integrate the scheduling information on the component carrier and the scheduling
15 information on the extension band into a group of information (for example, a set of
a start number and the number of blocks, or a bitmap).
[0085]
The radio communication unit 110 may transmit the ACK/NACK to uplink
transmission on the extension band in the uplink not on the extension band but on the
20 PHICH of the component carrier. Further, the radio communication unit 110 may
transmit the ACWNACK to downlink transmission on the extension band in the
downlink not on the extension band but on the PUCCH or the PUSCH of the
component carrier.
[0086]
25 (2) Network communication unit
Tllc network communication unit 120 is a communication interface
connected to the core network 16 exemplified in FIG. 1. Thc network
communication 120 relays a communication packet included in an uplink signal
received by the radio communication unit 110 to the core network 16. Further, the
30 network communication unit 120 receives a communication packet to be transmitted
using the downlink signal from the core network 16. Further, the network
communication unit 120 may exchange a control signal between itself and the
control node (for example, the MME) on the core network 16. Thc network
communication unit 120 may exchange the control signal via, for example, an X2
interface between itself and the base station in the adjacent cell.
[0087]
(3) Storage unit
The storage unit 130 stores a program and data for an operation of the base
station 100 by using a storage medium such as a hard disk or a semiconductor
memory. The data stored by the storage unit 130 may include, for example,
identification information (such as a terminal ID) and capability information for each
of the terminal apparatuses connected to the base station 100. The capability
information indicates whether each terminal apparatus is the non-legacy terminal or
the legacy terminal. Positional information (that may be dynamically updated) for
each of the terminal apparatuses may be stored by the storage unit 130.
[OOSS]
(4) Communication control unit
The communication control unit 140 controls the whole operation of the
base station by using a processor such as a central processing unit (CPU) or a digital
signal processor (DSP).
[OOS9]
For examplc, the communication control unit 140 sets the compo~ientc arrier
(CC) having the basic bandwidth selected from 6 alternatives of 1.4 MHz, 3 MHz, 5
MHz, 10 MHz, 15 MHz and 20 MHz to a usable frequency band. In the FDD
scheme, at least one downlink CC and at least one uplink CC are set. In the TDD
scheme, at least one CC common to the downlink and the uplink is set. Further, the
communication control unit 140 controls radio communication performed by the
legacy terminal and the non-legacy terminal on the component carrier, in the
resource block unit. Further, in an embodiment according to the present disclosure,
the communication control unit 140, when the excess frequency band exists, sets the
extension band to be added to the component carrier only to the excess frequency
band either on the upper side or the lower side of the component carrier. The
bandwidth or the extension band may be, for example, the integer multiple of the RB
size. The extension band is added to the component carrier to extend the bandwidth
of the component carrier.
[0090]
5 The communication control unit 140, when the extension band is set,
generates the BF setting information for notifying the terminal apparatus of the
setting of the extension band. As described using FIG. 11, the BF setting
information may include the flag for identifying the extension direction, and the
bandwidth information indicating the extension bandwidth. The bandwidth
10 information may be an index based on the number of resources corresponding to the
extension bandwidth.
[0091]
When radio communication is performed on the FDD scheme, the
communication control unit 140 sets the guard band on which radio signals are not
15 transmitted, to between the downlink CC and the extension band. This reduces
deterioration in reception quality in the legacy terminal, caused by transmission of
the downlink signal on the extension band. The communication control unit 140
may explicitly notify the terminal apparatus of the bandwidth of the guard band, for
example, by including information indicating the guard bandwidth into the BF
20 setting information. Instead, the communication control unit 140 may not explicitly
notify the terminal apparatus of the bandwidth of the guard band. For cxample, the
communication control unit 140 handles a part of the extension band as the guard
band (in this case, the bandwidth of the guard band is also the integer multiple of the
RB size), and prevents the radio communication unit 110 from transmitting the
25 downlink signal on the guard band (that is, assigns no downlink transmission to the
1 resource blocks included in the implicit guard band), to thereby realize the guard
band. The communication control unit 140 may dynamically change the bandwidth
of the guard band according to the reception quality reported from the terminal
apparatus. On the other hand, the communication control unit 140 sets no guard
I
I
I 30 band to between the uplink CC and the extension band added to the uplinlc CC.
I [0092]
FIG. 15 is an explanatory diagram illustrating a setting example of the
extension band set by the communication control unit 140. In this setting example,
the setting pattern of the extension band is the one-side setting. The usable
frequency band is 704 MHz-716 MHz and 734 MHz-746 MHz. For example, the
con~munication control unit 140 sets a downlink CC DC61 having the basic
bandwidth of 10 MI-Iz to a band of 734.6 MHz-743.6 MHz, and sets an uplink CC
UC64 having the same basic bandwidth of 10 MHz to a band of 704.6 MHz-713.6
MHz. Note that, when the basic bandwidth is 10 MHz, since channel gaps are
provided on both ends of the component carrier, an effective bandwidth is 9 MHz,
and the bandwidth includes 50 resource blocks in the frequency direction.
[0093]
The communication control unit 140 sets an extension band EB63 to be
added to the downlink CC DC61, to the excess frequency band on the upper side of
the downlink CC DC61. The extension band EB63 has an extension bandwidth of
1.44 MHz (743.96 MHz-745.4 MHz), and includes 8 resource blocks in the
frequency direction. A guard band GB62 having a bandwidth of 2 resource blocks
is set to between the downlink CC DC61 and the extension band EB63. Further, the
communication control unit 140 sets an extension band EB65 to be added to the
uplink CC UC64 to the excess frequency band on the upper side of the uplink CC
UC64. The extension band EB65 has an extension bandwidth of 1.8 MHz (713.6
MHz-715.4 MHz), and includes 10 resource blocks in the frequency di~cction. No
guard band is set to between the downlink CC DC64 and the extension band EB65.
[0094]
Note that the setting of the extension band shown in FIG. 15 is merely
examples for description. For example, the communication control unit 140 may
set the bandwidth of the component carrier, the extension band and the guard band to
values different from the examples described above. Further, the communication
control unit 140 may set the component carrier, the extension band and the guard
band whose numbers are different from the examples described above. Further, the
communication control unit 140, as described using FIG. 12, may set the component
carrier and the extension band so that the positional relationship between the
component carrier and the extension band in the frequency direction is reversed
between the overlapping or adjacent cells.
100951
The terminal apparatuses communicating with the base station 100 includes
the non-legacy terminals supporting radio communication on the extension band (a
first group of terminal apparatuses), and the legacy terminals not supporting radio
communication on the extension hand (a second group of terminal apparatuses).
The communication control unit 140 generates the resource assignment information
for the legacy terminal not depending on whether or not the extension band is set and
the extension bandwidth, and allows the radio communication unit 110 Lo transmit
the generated resource assignment information. The resource assignment
information may include the channel arrangement information indicating the
arrangement of the control channels such as the PRACH. Further, the resource
assignment information may include the scheduling information indicating the
resource blocks to be assigned to each terminal apparatus for data transmission. In
the resource assignment information, the individual resource blocks are identified by
using the resource block numbers uniquely granted to the respective resource blocks
through the component carrier and the extension band. Then, the resource block
numbers smaller than those of the resource blocks included in the extension hand are
granted to the resource blocks included in the component carrier. Accordingly, the
risk that the legacy terminal misunderstands the meaning of the resource block
numbers is solved to secure backward compatibility of the resource assignment
information.
[0096]
The communication control unit 140 may generate the resource assignment
information for the non-legacy terminal, separately from the resource assignment
information for the legacy terminal. For example, the PRACH for the non-legacy
terminal may be arranged separately from the PRACH for the legacy terminal. In
this case, the con~municationc ontrol unit 140 may allow the radio communication
unit 110 to transmit the PRACH arrangement information for the non-legacy
terminal, separately from the PRACH arrangement information for the legacy
terminal, conveyed by the SIB2. This makes it possible to assign the PRACH for
the non-legacy terminal to the extension band, and to assign more continuous
resource blocks to the legacy terminal on the PUSCH.
[0097]
5 Furthermore, the communication control unit 140 may preferentially assign
transmission of the uplink control signal (for example, the ACKINACIC to downlink
transmission, and a channel quality indicator (CQI)) of the non-legacy terminal to the
extension band. Also in this case, since a rate of the resources used by the nonlegacy
terminal among the resources of the uplink CC is reduced, it is possible to
10 assign more continuous resource blocks to the legacy terminal on the PUSCH.
[0098]
Furthermore, the communication control unit 140 may generate the
scheduling infonnation for the non-legacy terminal in a format different from that of
the scheduling information for the legacy terminal. As an example, the scheduling
15 information for the non-legacy terminal is designed so as to handle a start number
exceeding the number of the resource blocks included in the component carrier, and
the number of the blocks exceeding the number of the resource blocks. As another
example, the scheduling information for the non-legacy terminal is designed so as to
handle the bitmap up to the resource block number larger than the scheduling
20 information transmitted to the legacy terminal. This makes it possible to integrate
the scheduling infoln~ationo n the component carrier and the scheduling ~nformation
on the extension band into a group of information.
100991
Furthermore, the communication control unit 140 may assign downlink
25 transmission on the extension band for the non-legacy terminal closer to the center of
the cell, and may assign downlink transmission on the downlink CC for the legacy
terminal, and the non-legacy terminal closer to the cell edge. This can prevent largc
transmission power from being used on the extension band in the downlink to
suppress noise or interference generated in the legacy terminal caused by thc
30 downlink signal transmitted on the extension band.
[O 1001
<4, Configuration example of terminal apparatus>
In this section, an example of a configuration of a tcrminal apparatus 200
according to an embodiment will be described. The terminal apparatus 200 may be
any type of a radio communication terminal, for example, a smartphone, a personal
5 computer (PC), a personal digital assistants (PDA), a portable navigation device
(PND) or a game terminal. The tcrminal apparatus 200 is the non-legacy terminal
that supports radio communication on the extension band.
[0101]
FIG. 16 is a block diagram illustrating an example of the configuration of
10 the terminal apparatus 200. With reference to FIG. 16, the tcrminal apparatus 200
includes a radio communication unit 210, a storage unit 220, and a control unit 230.
[O 1021
(1) Radio communication unit
The radio commnnication unit 210 is a radio communication interface (or a
15 radio transmitter-receiver) that executes radio communication between itself and the
base station 100. The radio communication unit 210 transmits a radio signal to the
base station 100 and receives a radio signal from the base station 100, on the
component carrier CC having the basic bandwidth. Further, the radio
communication unit 210 transmits the radio signal to the base station 100 and
20 receives the radio signal from the base station 100, on the extension band according
to control by a comnunication control unit 234 to be described later. For example,
the radio communication unit 210 establishes synchronization with the downlink CC
by detecting the primary synchronization signal and the secondary synchronization
signal transmitted from the base station 100. When the extension band is set by the
25 base station 100, frame timing of the extension band is synchronized with kame
timing of the component carrier. Therefore, in this case, the radio communication
unit 210 can also establish synchronization with the extension band as well as the
downlink CC.
[0103]
30 The radio communication unit 210 receives the broadcast information
tra~~smitteodn the PBCH of the downlink CC. The broadcast illformation may
include, for example, the bandwidth information indicating the basic bandwidth of
the component carrier. The radio communication unit 210 further receives the BF
setting information indicating the setling related to the extcnsion band. For
example, the radio communication unit 210 may receive the BF setting information
5 in the MIB on the PBCH, in the SIB on the PDSCH, or in the individual signaling on
the PDCCI-I. Parameters of the radio communication unit 210 depending on the
band are set according to some indexes included in the BF setting information.
[0 1041
FIG. 17 is a bloclc diagram illustrating an example of the detailed
10 configuration of the radio communication unit 210 shown in FIG. 16. With
reference to FIG. 17, the radio communication unit 210 has a front end 211, an
orthogonal demodulation unit 212, a reception baseband unit 213, a transmission
baseband unit 2 14, and an orthogonal modulation unit 21 5.
[0105]
15 The front end 211 includes one or more transmission/reception antennas
(ANTS); a filter (FIL); an amplifier (AMP) and a band-pass filter (BPF) in a
reception branch; and a valuable gain amplifier (VGA), a band-pass filter (BPF), an
amplifier (AMP), and an isolator (ISO) in a transmission branch.
[0106]
20 The orthogonal demodulation unit 212 decomposes a reception signal
inputted from the liont end 211 into an I component and a Q component by a
frequency adjusted by a frequency synthesizer, and filters the I component and the Q
component by a low-pass filter (LPF). The low-pass filter removes out-of-band
noise, and aliasing noise that may be generated by AD conversion.
25 [0107]
The reception baseband unit 213 includes an analog-digital converter (AID),
a serial-parallel converter (SIP), a discrete Fourier transformer (DFT), a parallelserial
converter (PIS), and a demapper. The analog-digital converter converts a
received analog signal into a digital signal at a sampling rate corresponding to a
30 reception band. The discrete Fourier transformer converts a digital signal in a
frequency domain for each subcarrier, inputted from the serial-parallel converter, into
a digital signal in a time domain.
[0108]
The transmission baseband unit 214 includes a mapper, a serial-parallel
converter (SIP), an inverse discrete Fourier transformer (iDFT), a parallel-serial
6 converter (PIS); and a digital-analog converter (DIA). The inverse discrete Fourier
transformer converts a digital signal in a time domain for each subcarrier, inputted
from the serial-parallel converter, into a digital signal in a frequency domain. The
digital-analog converter converts a digital signal into a transmission analog signal at
a sampling rate corresponding to a transmission band.
10 [0109]
The orthogonal modulation unit 215 filters an I component and a Q
component of the transmission analog signal inputted from the transmission
baseband unit 214 by a low-pass filter (LPF), and modulates the filtered signal into a
transmission signal having a radio frequency by a frequency adjusted by the
15 frequency synthesizer. The transmission signal generated by the orthogonal
modulation unit 215 is then outputted to the front end 21 1.
[0110]
For example, the cut-off frequency of the low-pass filter exemplified in FIG.
17, the sampling rate of the AID conversion and the DIA conversion, and the FFT
20 size of the DFT and the inverse DFT are circuit parameters to be adjusted depending
on the transmissionlreception band (and the bandwidth thereal). Thcse circuit
parameters may be set according to a band setting signal generated by the
communication control unit 234 to be described later on the basis of the indexes
included in the BF setting information. As a result, the radio communication unit
25 210 can transmit and receive a radio sigual on the extension band.
I~ [0111] I
(2) Storage unit
!
!
I The storage unit 220 stores a program and data for operating the terminal
!
apparatus 200 by using a storage medium such as a bard disk or a semiconductor
30 memory. The data stored by the storage unit 220 may include, for example, the
bandwidth information indicating the basic bandwidth, and the BF setting
information.
[0ll2]
(3) Control unit
The control unit 230 controls the whole operation of the terminal apparatus
5 200 by using a processor such as a CPTJ or a DSP. In an embodiment according to
the present disclosure, the control unit 230 has an application unit 232, and the
communication control unit 234.
[0113]
The application unit 232 mounts an application in an upper layer thereon.
10 The application unit 232 generates data traffic to be transmitted to anothcr apparatus,
and outputs the generated data traffic to the radio communication unit 2 10. Further,
the application unit 232 processes the data traffic received by the radio
communication unit 210 from another apparatus.
[0114]
15 The communication control unit 234 controls radio communication
executed by the radio communication unit 210 according to a coritrol signal received
from the base station 100. The radio communication between the terminal
apparatus 200 and the base station 100 is typically controlled in the resource block
unit. For example, the communication control unit 234 sets the circuit parameters
20 of the radio communication unit 21 0 depending on the band so as to be fitted to the
basic bandwidth indicated by the broadcast information received by the radio
communication unit 210. This allows the radio communication unit 210 to transmit
and receive a radio signal on the component carrier.
[0115]
:I 25 Furthermore, the communication control unit 234, when the :i extension band is set to the excess frequency band by the base station 100, resets (adjusts) the circuit
parameters of the radio communication unit 210 depending on the band so as to be
fitted to the extension bandwidth indicated by the BF setting information received by
the radio communication unit 210. This allows the radio communication unit 210
30 to transmit and receive a radio signal on the extension band in addition to the
component carrier. When the extension band is set so as to have the extension
bandwidth of the integer multiple of the size of the RB, the BF setting information
received by the radio communication unit 210 can express the extension bandwidth
with a small number of bits on the basis of the number of the rcsource blocks
corresponding to the extension band width. The BF setting information may
include a flag indicating whether the extension band is set on the upper side or the
lower side of the component carrier.
[0116]
Furthermore, the communication control unit 234 allows the radio
communication unit 210 to execute radio communication according to the resource
assignment information received by the radio communication unit 210. The
resource assignment information may include the channel arrangement information
indicating the arrangement of the control channels such as the PRACH. For
example, the radio communication unit 210 is connected to the hase station 100 by
transmitting the random access signal to the base station 100 on the PRACH for the
legacy terminal indicated by the channel assignment information. The PRACH for
the non-legacy terminal, unlike the PRACH for the legacy terminal reported in the
SIB2, may be assigned to the resource blocks in the extension band. Further, the
radio communication unit 210 may transmit the uplink control signals such as the
ACWNACK to downlink transmission, and the CQI to the hase station 100 on the
PUCCH indicated by the channel assignment information.
[0117]
Furthermore, the resource assignment information may include the
scheduling information indicating the resource bloclts assigned to the terminal
apparatus 200 for data transmission. For example, the radio communication unit
210 receives the downlink signal or transmits the uplink signal in the resource bloclcs
indicated by the scheduling information.
[OllS]
When the extension hand is set, the resourcc assignment inlormation
described above is generated based on the resource block numbers uniquely granted
to the respective resource blocks through the component carrier and the extension
band. The rcsource block numbers smaller than those of the resource bloclcs
SP352626WO00
43160
included in the extension band are granted to the resource blocks included in the
I component carrier. Therefore, a format of the resource assignment information
i
received by the terminal apparatus 200 as the non-legacy terminal may be different
depending on whether or not the extension band is set. For example, when the
5 extension band is not set, the maximum value of the resource block numbers that
may be identified by the resource assignment information corresponds to the number
of the resource blocks of the component carrier. In contrast, when the extension
band is set, the maximum value of the resource block numbers that may be identified
by the resource assignment information corresponds to the sum of the number of the
10 resource bloclcs of the component carrier and the number of the resourcc blocks of
the extension band (that may include the guard band). Further, the size of the
I scheduling information expressed in a bitmap format when the extension band is set,
I i becomes large than the size when the extension band is not set. The communication
control unit 234 interprets these pieces of resource assignment information according ~ 15 to the setting of the extension band, and controls radio communication executed by
1
the radio communication unit 210.
I
.! [0119]
, , Note that a format of the resource assignment information received by the
legacy terminal is not changed depending whether or not the extension band is set, as
20 a result of the adoption of the new numbering rule described above.
[OlZO]
<5. Flow of processing>
In this section, a flow of processing in a radio communication system
including the base station 100 and the terminal apparatus 200 will be described using
::
25 FIG. 18 to FIG. 20.
,!
,!
[0121]
[5-1. Band setting processing]
FIG. 18 is a flow chart illustrating an example of a flow of band setting
processing executed by the base station 100.
30 [0122]
With reference to FIG. 18, first, the communication control unit 140 of the
base station 100 sets the one or more component carriers in the usable frequency
band (Step S1). Next, the communication control unit 140 determines whether or
not the excess frequency band exists (Step S2). When the excess frequency band
does not exist, the subsequent processing shown in FIG. 18 is skipped. When the
5 excess frequency band exists, the processing proceeds to Step S3.
[0123]
At Step S3, the communication control unit 140 sets the extension band to
the excess frequency band on the upper side or the lower side of the component
carrier (Step S3). The extension band set here is added to the component carrier to
10 extend the basic bandwidth of the component carrier. Next, the communication
control unit 140 sets the band adjacent to the downlink CC to the guard band (Step
S4). The guard band may be handled as a part of the extension band. Next, the
communication control unit 140 grants the unique resource block numbers to the
resource blocks in the component carrier and the extension band added to the
15 component carrier according to the new numbering rule (Step S5). Next, the
communication control unit 140 determines the arrangement of some channels (Step
S6). For example, the synchronization resource and the broadcast channel are
arranged in the resource blocks in the center of the downlink CC. The PRACH for
the legacy terminal is arranged in a part of the PUSCH of the uplink CC. The
20 PRACH for the non-legacy terminal is arranged in the extension band in the uplink.
Next, the communication control unit 140 generates the BF setting incormation
including the index indicating the setting of the extension band (Step S7).
[0124]
The band setting processing described here may be executed when the base
25 station 100 initializes the operation of thc cell, or may be executed during the
operation (for example, periodically) in order to dynamically update the setting of the
extension band.
[0125]
[5-2. Communication control processing]
30 FIG. 19A and FIG. 19B are a sequence diagram illustrating an example of a
flow ~Tcommunicationc ontrol processing according to an embodiment.
[0126]
With reference to FIG. 19A, first, the base station 100 sets the one or more
component carriers and the one or more extension bands to the usable frequency
band by executing the band setting processing described using FIG. 18 (Step S 10).
5 [0127]
Next, the base station 100 transmits the primary synchronization signal and
the secondary synchronization signal on the synchronization resource arranged in the
resource blocks in the center of the downlink CC (Step S11). The terminal
apparatus 200 as the non-legacy terminal establishes synchronization with the base
10 station 100 by recciving such synchronization signals (Step S13).
[O 1281
Next, the base station 100 transmits the broadcast information including the
bandwidth information indicating the basic bandwidth on the broadcast channel of
the downlink CC (Step S15). The communication control unit 234 of the terminal
15 apparatus 200 sets the circuit parameters of the radio communication unit 210
depending on the band so as to be fitted to the basic bandwidth indicated by the
rcccived broadcast information (Step S17). Note that the legacy terminal also
receives these synchronization signals and the broadcast information from the base
station 100.
20 [0129]
When the circuit parameters of the radio communication unit 210 are set so
as to be fitted to the basic bandwidth in the terminal apparatus 200, it is possible to
transmit and receive the radio signal on the component carrier. Next, the terminal
apparatus 200 transmits a connection request to the base station 100 on the uplink
25 CC (Step S19). The base station 100 transmits connection grant to the terminal
apparatus 200 in response to the connection request from the terminal apparatus 200
(Step S21).
[0130]
Next, the base station 100 transmits an inquiry signal for inquiring
30 capability of the terminal apparatus 200 to the terminal apparatus 200 on thc
downlink CC (Step S23). The terminal apparatus 200 transmits a capability
response to the base station 100 in response to the inquiry signal from the base
station 100 (Step S25). The capability response transmitted here includes capability
information indicating that the terminal apparatus 200 is the non-legacy terminal,
that is, it supports radio communication on the extension band.
5 [0131]
Next, the base station 100 transmits the BF setting information including the
index indicating the setting of the extension band to the terminal apparatus 200 (Step
S27). The communication control unit 234 of the terminal apparatus 200 adjusts
the circuit parameters of the radio communication unit 210 depending on the band so
10 as to be fitted to the extension bandwidth (or the sum of the basic bandwidth and the
extension bandwidth) indicated by the received BF setting information (Step S29).
The terminal apparatus 200 then transmits a BF setting completion report to the base
station 100 (Step S3 1).
101321
15 After that, the sequence moves to FIG. 19B. When the downlink data
addressed to the terminal apparatus 200 occurs (Step S33), the base station 100
assigns the downlink transmission to the terminal apparatus 200 to the resource
blocks in the downlink CC or the extension band added to the downlink CC (Step
S35). Next, the base station 100 transmits the scheduling information indicating the
20 downlink assignment, for example, to the terminal apparatus 200 on the PDCCH of
the downlink CC (Stcp S37). The base station 100 then transmits the downlink data
to the terminal apparatus 200 by using the assigned resource blocks (Step S39).
[0133]
Furthermore, when the uplink data addressed to another apparatus occurs
26 (Step S41), the terminal apparatus 200 transmits a scheduling request to the base
I!
I
I
station 100 (Step S43). The base station 100 assigns the uplink transmission from
,I
the terminal apparatus 200 to the resource blocks in the uplink CC or the extension
band added to the uplink CC in response to the reception of the scheduling request
(Step S45). Next, the base station 100 transmits the scheduling information
30 indicating the uplink grant to the terminal apparatus 200, for example, on the
PDCCH of the downlink CC (Stcp S47). The terminal apparatus 200 then transmits
the uplink data to the base station 100 by using the assigned resource blocks (Step
S49).
[0134]
Note that there has been described here the example that, after the base
station 100 has confirmed the capability of the terminal apparatus 200, the base
station 100 transmits the BF setting information to the terminal apparatus 200.
However, the base station 100 may broadcast the BF setting information into the cell
before confirming the capability of the terminal apparatus 200.
[0135]
[5-3. Scheduling processing]
FIG. 20 is a flow chart illustrating an example of a flow of scheduling
processing according to an embodiment.
[0136]
With reference to FIG. 20, first, the communication control unit 140 of the
base station 100 recognizes the necessity of the scheduling (Step S61). For
example, the communication control unit 140 may recognize the necessity of the
scheduling by recognizing that the downlink data addressed to a certain terminal
apparatus has been delivered, or by receiving the scheduling request for the uplink
data from the terminal apparatus.
[0137]
The communication control unit 140 that has recognized the necchsity of the
scheduling for a certain terminal, determines the capability of the terminal apparatus
(Step S62). The capability information of each terminal apparatus may be acquired
in advance through the response to the capability inquiry, and may be stored by the
storage 130 ofthe base station 100.
101381
When the terminal apparatus is the uon-legacy terminal, the communication
control unit 140 further determines the position of the non-legacy terminal (Step
S64). For example, the position of the terminal may be measured using a GPS
signal in the terminal and reported to the base station 100, or may be mcasurcd in the
base station 100.
The communication control unit 140, when the determined position is close
to the center of the cell (for example, the distance from the base station 100 is below
a predetermined value), assigns the resource blocks in the extension band to the non-
5 legacy terminal (Step S66). On the other hand, the communication control unit 140,
when the deteimined position is close to the cell edge, assigns the resource bloclts in
the component carrier to the non-legacy terniinal (Step S67). Note that, for the
uplink, Step S64 and Step S65 may be omitted. In this case, the uplink transmission
of the non-legacy terminal is assigned preferentially to the resource blocks in the
10 extension band.
[0140]
Furthermore, when the terminal apparatus is the legacy terminal, the
communication control unit 140 assigns the resource blocks in the component carrier
to the legacy terminal (Step S67).
15 [0141]
The communication control unit 140 generates the scheduling information
indicating the result of the scheduling, and allows the radio communication unit 110
to transmit the generated scheduling information (Stcp S68). The format of the
scheduling information for the non-legacy terminal may be different &om the format
20 of the scheduling information for the legacy terminal.
[0 1421
Note that the flow of the processing described using FIG. 18 to FIG. 20 is
merely an example. The order of the processing steps may be changed, and the
processing steps may be partially omitted, or an additional processing step may be
1
I
25 introduced.
1 [0143]
I
'I
i
<6. Summary>
;I
Up to here, the embodiments of the technology according to the disclosure
have been described in detail. According to the embodiments described above, the
30 extension band to be added to the component carrier is set only to the excess
frequency band either on the upper side or the lower side of the component carrier
having the basic bandwidth. Therefore, for example, in the downlink, when one
guard band is set to between the component carrier and the extension band, it is
possible to avoid deterioration in reception quality in the legacy terminal. This
makes it possible to realize the appropriate balance between the avoidance of the
5 deterioration in reception quality and the resource utilization efficiency. Further, in
the uplink, securing the wide and continuous bandwidth as much as possible for the
extension band allows the non-legacy terminal to perform uplink transmission with
excellent power efficiency.
[0144]
10 Furthermore, in a certain embodiment, the synchronization resource on
which the synchronization signal for synchronizing the non-legacy terminal with
both of the component carrier and the extension band is transmitted, is assigned to
the center of the downlink CC. The arrangement of the synchronization resource is
similar to the arrangement when the extension band is not set. Therefore, the cell
15 search procedure of the legacy terminal is not affected by whether or not the
extension band is set. Further, since the synchronization resource may not be
arranged in the extension band having the relatively narrow bandwidth, it is possible
to avoid an increase in rate of the overhead of the resource. The broadcast channel
may be also assigned to the center of the downlink CC.
20 [0145]
Furthermorc, in a certain embodiment, when the positional relationship
between the component carrier and the extension band in the frequency direction is
set in a manner that the positional relationship is reversed between the overlapping or
adjacent cells, it is also possible to suppress the inter-cell interference caused by
25 transmission on the extension band.
[0146]
Note that a serics of control processing by each apparatus described in this
specification may be achieved by using any of software, hardware, and a
combination of software and hardware. A program constituting software is stored
30 in a storage medium (non-transitory media) in advance, the medium being provided
in the inside or outside of each apparatus, for example. When each program is
I
I executed, for example, the program is read by random access memory (RAM) and
executed by a processor such as a CPU.
[0 1471
The preferred embodiments of the present disclosure have been described
5 above in detail with reference to the accompanying drawings, whilst the present
disclosure is not limited to the above examples, of course. A person skilled in the
art may find various alterations and modifications within the scope of the appended
claims, and it should be understood that they will naturally come under the technical
scope of the present disclosure.
lo [0148]
Additionally, the present technology may also be configured as below
(1)
A communication control apparatus including:
I
I a communication control unit that controls radio communication performed
I 15 by one or more terminal apparatuses on a component carrier having a basic
I
:I bidwidth,
wherein the communication control unit sets an extension band to be added
to the component carrier only to an excess frequency band either on an upper side or
a lower side of the component carrier.
20 (2)
The comillunication control apparatus according to (I),
wherein the radio communication is pcrformed by a frequency division
duplex (FDD) scheme,
wherein the component carrier is a downlink component carrier, and
25 wherein the communication control unit sets a guard band on which a radio
signal is not transmitted, to between the downlink component carrier and the
I extension band.
(3)
The communication control apparatus according to (2),
30 wherein the communication control unit does not set the guard band to
between an uplink component carrier and an extension baud added lo the uplink
component carrier.
(4)
The communication control apparatus according to any one of (1) to (3),
wherein the communication control unit assigns a resource on which a
5 synchronization signal for synchronizing the terminal apparatus with both of the
component carrier and the extension band is transmitted, to a center of the
component carrier.
(5)
The communication control apparatus according to any one of (I) to (4),
10 wherein the comniunication control unit controls the radio comanunication
in a resource block unit, and sets a bandwidth of the extension band to an integer
multiple of a size of a resource block.
(6)
The communication control apparatus according to (5),
15 wherein the communication control unit uses an index based on the number
of resource blocks corresponding to the bandwidth of the extension band to notify the
terminal apparatus of the setting of the extension band.
(7)
The communication control apparatus according to (4),
20 wherein the communication control unit sets the component carrier and the
extension band in a manner that a positional relationship between the component
carrier and the extension band in a frequency direction is reversed between
overlapping or adjacent cells.
(8)
25 The communication control apparatus according to any one of (1) to (7),
further including:
a radio communication unit that transmits setting information related to the
extension band on the component carricr.
(9)
30 The communication control apparatus according to any one of (1) to (a),
further including:
a radio communication unit that transmits scheduling information related to
the extension band on the component carrier to the terminal apparatus.
(10)
The communication control apparatus according to any one of (1) to (9),
5 wherein the one or more terminal apparatuses include a first group of
terminal apparatuses that support radio communication on the extension band, and a
second group of terminal apparatuses that do not support the radio communication on
the extension band, and
wherein the communication control unit transmits resource assignment
10 information that is not changed depending on whether or not the extension band is
set, for the second group of terminal apparatuses.
(11)
The communication control apparatus according to (1 0),
wherein the resource assignment information is generated based on resource
15 block numbers uniquely granted to respective resource blocks through the
component carrier and the extension band, and
wherein the resource block numbers smaller than the resource block
numbers of the resource blocks included in the extension band are granted to the
resource blocks included in the component carrier regardless of whether the
20 extension band is set to either the upper side or the lower side of the component
carrier.
(12)
The communication control apparatus according to (10) or (ll),
wherein the resource assignment information includes at least one of
25 scheduling information and channel arrangement information transmitted on the
component carrier.
(13)
The communication control apparatus according to (I),
wherein the radio communication is performed by a frequency division
30 duplex (FDD) scheme, and
wherein the component carrier is an uplink component carrier.
The communication control apparatus according to (13),
wherein the communication control unit preferentially assigns transmission
of a non-data signal in an uplink of a first group of terminal apparatuses that support
5 the radio communication on the extension band, to the extension band
(15)
The communication control apparatus according to (14),
wherein the non-data signal is an random access signal.
(16)
10 The communication control apparatus according to (1 5),
wherein the communication control unit assigns a first random access
channel for the first group of terminal apparatuses to resource blocks in the extension
band, and assigns a second random access channel for a second group of terminal
apparatuses that do not support the radio communication on the extension band, to
15 resource bloclts in the component carrier.
(17)
A communication control method including:
controlling radio communication performed by one or more terminal
apparatuses on a component carrier having a basic bandwidth; and
20 setting an extension band to be added to the component carrier only to an
excess frequency baud either on an upper side or a lower side of thc component
carrier.
(18)
A radio communication system including:
25 one or more terminal apparatuses; and
a communication control apparatus,
wherein the communication control apparatus sets an extension band to be
added to the component carrier only to an excess frequency band either on an upper
side or a lower side of the component carrier having a basic bandwidth, and
30 wherein at least one of the terminal apparatuses executes radio
communication on the extension band.
1
I
A terminal apparatus including:
a radio communication unit that communicates with a communication
control apparatus controlling radio communication performed on a component carrier
5 having a basic-bandwidth, the communication control apparatus setting an extension
band to be added to the component carrier only to an excess frequency band either on
an upper side or a lower side of the component carrier; and
a control unit that, when the extension band is set by the communication
control apparatus, allows the radio con~munication unit to execute the radio
10 communication on the set extension band.
(20)
The terminal apparatus according to (1 9),
wherein the control unit sets a parameter of the radio communication unit
depending on a band according to an index indicating the setting of the extension
I 15 band received from the communication control apparatus, and i
wherein the index indicates whether the extension band is set to either the
upper side or the lower side of the component carrier.
Reference Signs List
20 101491
100 communication control apparatus (base station)
110 radio communicatiou unit
140 communication control unit
200 terminal apparatus (non-legacy terminal)
25 21 0 radio communicatiou unit
I 234 communication control unit

CLAIMS
Claim 1
A communication control apparatus comprising:
a communication control unit that controls radio communication performed
5 by one or more terminal apparatuses on a component carrier having a basic
bandwidth,
wherein the communication control unit sets an extension band to be added
to the component carrier only to an excess frequency band either on an upper side or
a lower side of the component carrier.
10
Claim 2
The communication control apparatus according to claim 1,
wherein the radio communication is performed by a frequency division
duplex (FDD) scheme,
I
I 15 wherein the component carrier is a downlink component carrier, and
I
i
, I wherein the communication control unit sets a guard band on which a radio
! signal is not transmitted, to between the downlink component carrier and the
I extension band.
20 Claim 3
The communication control apparatus according to claim 2,
wherein the communication control unit does not set the guard band to
between an uplink component carrier and an extension band added to the uplink
component carrier.
25
Claim 4
I :I The communication control apparatus according to claim 1,
I wherein the communication control unit assigns a resource on which a
I
I
I synchronization signal for synchronizing the terminal apparatus with both of the
I
30 component carrier and the extension band is transmitted, to a center of the
component carrier.
! Claim 5
The communication control apparatus according to claim 1,
wherein the communication control unit controls the radio communication
5 in a resource block unit, and sets a bandwidth of the extension band to an integer
multiple of a size of a resource block.
Claim 6
The communication control apparatus according to claim 5,
10 wherein the communication control unit uses an index based on the number
of resource blocks corresponding to the bandwidth of the extension band to notify the
terminal apparatus of the setting of the extension band.
Claim 7
15 The communication control apparatus according to claim 4,
wherein the communication control unit sets the component carrier and the
extension band in a manner that a positional relationship between the component
carrier and the extension band in a frequency direction is reversed between
overlapping or adjacent cells.
20
Claim 8
The communication control apparatus according to claim 1, further
comprising:
a radio communication unit that transmits setting information related to the
25 extension band on thc component carrier.
Claim 9
The communication control apparatus according to claim 1, further
comprising:
30 a radio communication unit that transmits scheduling information related to
the extension band on the component carrier to the terminal apparatus.
Claim 10
The communication control apparatus according to claim 1,
wherein the one or more terminal apparatuses include a first group of
5 terminal apparatuses that support radio communication on the extension band, and a
second group of terminal apparatuses that do not suppot~h e radio communication on
the extension band, and
wherein the communication control unit transmits resource assignment
information that is not changed depending on whether or not the extension band is
10 set, for the second group of terminal apparatuses.
Claim 11
The communication control apparatus according to claim 10,
wherein the resource assignment information is generated based on resource
15 block numbers uniquely granted to respective resource bloclcs through the
component carrier and the extension band, and
wherein the resource block numbers smaller than the resource block
numbers of the resource blocks included in the extension band are granted to the
resource blocks included in the component carrier regardless of whether the
20 extension band is set to either the upper side or the lower side of the component
carrier.
,I Claim 12
,I The communication control apparatus according to claim 10, I:1
!I 25 wherein the resource assignment information includes at least one of
:I
:I scheduling information and channel arrangement information transmitted on the
4 I
i
1 component carrier.
,I
Claim 13
30 The communication control apparatus according to claim 1,
wherein the radio comn~unication is performed by a frequency division
duplex (FDD) scheme, and
wherein the component carrier is an uplink component carrier.
1 Claim 14
5 The communication control apparatus according to claim 13,
wherein the communication control unit preferentially assigns transmission
of a non-data signal in an uplink of a first group of terminal apparatuses that support
the radio communication on the extension band, to the extension band.
10 Claim 15
The communication control apparatus according to claim 14,
wherein the non-data signal is an random access signal.
Claim 16
15 The communication control apparatus according to claim 15,
I wherein the communication control unit assigns a first random access
channel for the first group of terminal apparatuses to resource bloclts in the extension
band, and assigns a second random access channel for a second group of terminal
apparatuses that do not support the radio communication on the extension band, to
20 resource blocks in the component carrier.
Claim 17
A communication control method comprising:
controlling radio comnlunication performed by one or more terminal
I i 25 apparatuses on a component carrier having a basic bandwidth; and
! setting an extension band to be added to the component carrier only to an
I excess frequency band either on an upper side or a lower side of the conlponent
I
carrier.
30 Claim 18
A radio communication system comprising:
one or more terminal apparatuses; and
a communication control apparatus,
wherein the communication control apparatus sets an extension band to be
added to the component carrier only to an excess frequency band either on an upper
5 side or a lower side of the component carrier having a basic bandwidth, and
wherein at least one of the terminal apparatuses executes radio
communication on the extension band.
Claim 19
10 A terminal apparatus comprising:
a radio comn~unication unit that communicates with a communication
control apparatus controlling radio communication performed on a component carrier
having a basic bandwidth, fhe communication control apparatus setting an extension
band to be added to the component carrier only to an excess frequency band either on
15 an upper side or a lower side of the component carrier; and
a control unit that, when the extension band is set by the communication
control apparatus, allows the radio communication unit to execute the radio
communication on the set extension band.
20 Claim20
The terminsll apparatus according to claim 19,
wherein the control unit sets a parameter of the radio communication unit
depending on a band according to an index indicating the setting of the extension
band received from the communication control apparatus, and
25 wherein the index indicates whether the extension band is set to either the
upper side or the lower side of the component carrier