Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
Method, Device and System for Cell Handover in Telecommunication
System Supporting Carrier Aggregation
Field
5 [01] The invention relates to the field of communications supporting carrier
aggregation (CA), and particularly to methods and apparatuses for cell handover in a
communication system supporting carrier aggregation, and terminal devices, base
stations and communication systems including such apparatuses or using such
methods.
10
Background
[02] The future LTE-A (Long Term Evolution-Advanced) system supports a
transmission bandwidth up to lOOMHz, while in the current LTE standard the
maximum supportable transmission bandwidth is 20MHz such that a plurality of
15 carriers need to be aggregated for broader bandwidth transmission. Carrier
aggregation is a technique presented by 3 GPP to support the higher requirement for
transmission bandwidth in the future mobile communication system, in which a
plurality of carriers are aggregated for transmission. The introduction of the CA
technique brings about new chances and challenges for the development of the
20 communication techniques.
Summary
[03] A communication system which supports CA, such as LTE-A, can support
various CA scenarios, for example, consecutive CA and non-consecutive CA
25 scenarios. This results in the diversity of the scenarios when a terminal device in a
communication system is handed over between cells. Due to such diversity, a single
handover algorithm cannot be applied to all the scenarios. Some embodiments of the
invention provide a scheme of adaptively selecting the cell handover algorithms
based on the CA scenario in which a terminal device is located when the terminal
30 device is to be handed over. Particularly, some embodiments of the invention
methods and apparatuses for cell handover in a communication system supporting
1
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: OP 1211-06-0477
EN Translation of PCT Spec
CA, and terminal devices, base stations and communication systems including such
apparatuses or using such methods.
[04] The following presents a simplified summary of the disclosure in order to
provide a basic understanding of some aspects of the disclosure. This summary is
5 not an exhaustive overview of the disclosure. It is not intended to identify key or
critical elements of the disclosure or to delineate the scope of the disclosure. Its sole
purpose is to present some concepts in a simplified form as a prelude to the more
detailed description that is discussed later.
[05] According to an aspect of the invention, there is provided a method for cell
10 handover in a communication system supporting carrier aggregation, which may
include: selecting, by a terminal device in the communication system when the
terminal device moves to edge of a currently serving cell, one or more from one or
more neighbor cells based on carrier aggregation manners of the one or more
neighbor cells, as objects to be measured; measuring, by the terminal device,
15 performances of the objects to be measured to obtain one or more measurement
results; and transmitting, by the terminal device, the one or more measurement
results to a source base station currently serving the terminal device, as a
performance measurement report of the one or more neighbor cells.
[06] According to another aspect of the invention, there is provided an apparatus for
20 cell handover, configured in a terminal device in a communication system
supporting carrier aggregation and including: a measurement object selecting device,
configured to select, when the terminal device moves to edge of a currently serving
cell, one or more from one or more neighbor cells based on carrier aggregation
manners of the one or more neighbor cells, as objects to be measured; a cell
25 measuring device, configured to measure performances of the objects to be
measured to obtain one or more measurement results; and a transmitting device,
configured to transmit the one or more measurement results obtained by the cell
measuring device to a source base station currently serving the terminal device, as a
performance measurement report of the one or more neighbor cells.
30 [07] According to another aspect of the invention, there is provided a terminal
device in a communication system supporting carrier aggregation. The terminal
device may include the above apparatus for cell handover.
2
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
[08] According to another aspect of the invention, there is provided a method for
cell handover in a communication system supporting carrier aggregation. The
method includes: selecting, by a source base station when receiving a performance
measurement report of one or more neighbor cells from a terminal device served by
5 the source base station, an algorithm suitable to the carrier aggregation manners of
one or more candidate base stations corresponding to the one or more neighbor cells
based on the performance measurement report and based on the carrier aggregation
manners to calculate priorities of the one or more candidate base stations; selecting
one having highest priority from the one or more candidate base stations, as a
10 destination base station; and selecting one or more cells to be accessed for the
terminal device from all cells belonging to the destination base station in the one or
more neighbor cells.
[09] According to another aspect of the invention, there is provided an apparatus for
cell handover, configured in the base station of the communication system
15 supporting carrier aggregation and including: a receiving device configured to
receive a performance measurement report of one or more neighbor cells from a
terminal device served by the base station; a priority determining device configured
to select an algorithm suitable to the carrier aggregation manners of one or more
candidate base stations corresponding to the one or more neighbor cells based on the
20 performance measurement report and based on the carrier aggregation manners to
calculate priorities of the one or more candidate base stations; a destination base
station selecting device configured to select one having highest priority from the one
or more candidate base stations, as a destination base station; and a cell selecting
device configured to select one or more cells to be accessed for the terminal device
25 from all cells belonging to the destination base station in the one or more neighbor
cells.
[10] According to another aspect of the invention, there is provided a base station in
a communication system supporting carrier aggregation. The base station includes
the above apparatus for cell handover.
30 [11] According to another aspect of the invention, there is provided a method for
cell handover in a communication system supporting carrier aggregation. The
method includes: judging, by a source base station in the communication system,
3
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
whether or not the component carriers corresponding to one or more cells to be
accessed belonging to a destination base station selected by a terminal device which
is served by the source base station and is to be handed over are in a same frequency
band, and if yes, packaging configuration information of all the cells to be accessed
5 in a handover command for initiating the handover of the terminal device, otherwise,
packaging configuration information of one of the cells to be accessed in the
handover command; and transmitting the handover command.
[12] According to another aspect of the invention, there is provided an apparatus for
cell handover, configured in a base station in the communication system supporting
10 carrier aggregation and including: a demand forming device configured to judge
whether or not the component carriers corresponding to one or more cells to be
accessed belonging to a destination base station selected by a terminal device which
is served by the present base station and is to be handed over are in a same
frequency band, and if yes, package configuration information of all the cells to be
15 accessed in a handover command for initiating the handover of the terminal device,
otherwise, package configuration information of one of the cells to be accessed in
the handover command; and a transmitting device configured to transmit the
handover command.
[13] According to another aspect of the invention, there is provided a base station in
20 a communication system supporting carrier aggregation. The base station includes
the above apparatus for cell handover.
[14] According to another aspect of the invention, there is provided a method for
cell handover in a communication system supporting carrier aggregation. The
method includes: selecting, by a terminal device in the communication system when
25 the terminal device moves to edge of a currently serving cell, one or more from one
or more neighbor cells based on carrier aggregation manners of the one or more
neighbor cells, as objects to be measured; measuring, by the terminal device,
performances of the objects to be measured to obtain one or more measurement
results; transmitting, by the terminal device, the one or more measurement results to
30 a source base station currently serving the terminal device, as a performance
measurement report of the one or more neighbor cells; selecting, by the source base
station when receiving the performance measurement report from the terminal
4
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: OP 1211-06-0477
EN Translation of PCT Spec
device, an algorithm suitable to the carrier aggregation manners of one or more
candidate base stations corresponding to the one or more neighbor cells based on the
performance measurement report and based on the carrier aggregation manners to
calculate priorities of the one or more candidate base stations; selecting one having
5 highest priority from the one or more candidate base stations, as a destination base
station; and selecting one or more cells to be accessed for the terminal device from
all cells belonging to the destination base station in the one or more neighbor cells.
[15] According to another aspect of the invention, there is provided a method for
cell handover in a communication system supporting carrier aggregation. The
10 method includes: selecting, by a terminal device in the communication system when
the terminal device moves to edge of a currently serving cell, one or more from one
or more neighbor cells based on carrier aggregation manners of the one or more
neighbor cells, as objects to be measured; measuring, by the terminal device,
performances of the objects to be measured to obtain one or more measurement
15 results; transmitting, by the terminal device, the one or more measurement results
to a source base station currently serving the terminal device, as a performance
measurement report of the one or more neighbor cells; selecting, by the source base
station when receiving the performance measurement report from the terminal
device, one from one or more candidate base stations corresponding to the one or
20 more neighbor cells based on the performance measurement report, as a destination
base station, and selecting one or more cells to be accessed for the terminal device
from all cells belonging to the destination base station in the one or more neighbor
cells; if component carriers corresponding to the cells to be accessed are in a same
frequency band, packaging configuration information of all the cells to be accessed
25 in a handover command for initiating cell handover; otherwise, packaging
configuration information of one or more among the cells to be accessed in the
handover command; and transmitting the handover command.
[16] According to another aspect of the invention, there is provided a
communication system supporting carrier aggregation, including the above terminal
30 device and/or the above base station.
[17] Li addition, some embodiments of the disclosure fiirther provide computer
program for realizing the above methods.
5
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
• Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
[18] Further, some embodiments of the disclosure further provide computer
program products in at least the form of computer-readable medium, upon which
computer program codes for realizing the above methods are recorded.
5 Brief Description of Drawings
[19] The above and other objects, features and advantages of the embodiments of
the disclosure can be better understood with reference to the description given below
in conjunction with the accompanying drawings, throughout which identical or like
components are denoted by identical or like reference signs. In addition the
10 components shown in the drawings are merely to illustrate the principle of the
disclosure. In the drawings:
[20] Figure 1 is a schematic flow chart showing a method of cell handover for a
terminal device in a communication system according to an embodiment of the
invention;
15 [21] Figure 2 is a schematic flow chart showing a method of a terminal device
selecting an object to be measured according to an embodiment of the invention;
[22] Figure 3 is a schematic flow chart showing a method of filtering the measure
results by a terminal device before sending a performance measurement report to a
source base station according to an embodiment of the invention;
20 [23] Figure 4 is a schematic flow chart showing a method of filtering the measure
results by a terminal device before sending a performance measurement report to a
source base station according to another embodiment of the invention;
[24] Figure 5 is a schematic flow chart showing an method of object comparison in
order to filter the measure results by a terminal device according to an embodiment
25 of the invention;
[25] Figure 6 is a schematic flow chart showing an method of object comparison in
order to filter the measure results by a terminal device according to another
embodiment of the invention;
[26] Figure 7 is a schematic block diagram showing the structure of an apparatus
30 for cell handover according to an embodiment of the invention;
6
Sony China Ref.: CNPA10034IN00
# Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
[27] Figure 8 is a schematic block diagram showing the structure of an apparatus
for cell handover according to another embodiment of the invention;
[28] Figure 9 is a schematic flow chart showing a method for cell handover
performed by a source base station in a communication system according to an
5 embodiment of the invention;
[29] Figure 10 is a schematic flow chart showing a method of calculating by a
source base station the priority of a candidate base station based on the performance
measurement report sent from the terminal device according to an embodiment of
the invention;
10 [30] Figure 11 is a schematic flow chart showing a method of selecting by a source
base station a cell to be accessed based on the CA manners of a destination base
station according to an embodiment of the invention;
[31] Figure 12 is a schematic flow chart showing a method of selecting by a source
base station a primary cell to be accessed based on the CA manners of a destination
15 base station according to an embodiment of the invention;
[32] Figure 13 is a schematic flow chart showing a method of forming by a source
base station a handover command based on the CA manner of the selected cell to be
accessed according to an embodiment of the invention;
[33] Figure 14 is a schematic block diagram showing the structure of an apparatus
20 for cell handover configured in a base station of a communication system supporting
CA according to an embodiment of the invention;
[34] Figure 15 is a schematic flow chart showing a method of cell handover
performed by a source base station in a communication system according to an
embodiment of the invention;
25 [35] Figure 16 is a schematic block diagram showing the structure of an apparatus
for cell handover configured in a base station of a communication system supporting
CA according to an embodiment of the invention;
[36] Figure 17, Figure 18, and Figure 19 each show an application scenario to
which the methods of cell handover according to the above embodiments can be
30 applied;
7
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
[37] Figure 20 is a schematic block diagram showing the structure of an apparatus
for cell handover configured in a base station of a communication system supporting
CA according to another embodiment of the invention; and
[38] Figure 21 is a schematic block diagram showing the structure of a computer
5 with which the embodiments of the invention can be realized.
Detailed Description
[39] Some embodiments of the present disclosure will be described in conjunction
with the accompanying drawings hereinafter. It should be noted that the elements
10 and/or features shown in a drawing or disclosed in an embodiments may be
combined with the elements and/or features shown in one or more other drawing or
embodiments. It should be further noted that some details regarding some
components and/or processes irrelevant to the disclosure or well known in the art are
omitted for the sake of clarity and conciseness.
15 [40] Some embodiments of the present disclosure provide a scheme of adaptively
selecting the cell handover algorithms based on the CA scenario in which a terminal
device is located when the terminal device is to be handed over. In the disclosure, a
base station (BS) to which a currently serving cell of a terminal device belongs is
referred to as a source base station (i.e. a base station currently serving the terminal
20 device), a base station to which a neighbor cell of the terminal device belongs is
referred to a candidate destination base station or a candidate base station, and a
base station to which a cell, to which the terminal device is finally handed, belongs
is referred to as a destination base station. The so-called neighbor cell refers to a cell
whose coverage is adjacent to that of the currently serving cell of a terminal device,
25 which may be detected by the terminal device when the terminal device moves to
the edge of the coverage of the currently serving cell.
[41] Figure 1 shows a method of a terminal device being handed over between cells
in a communication system supporting CA according to an embodiment of the
invention.
30 [42] When a terminal device is to perform cell handover, the terminal device needs
to measure the performances of its neighbor cells. At this time, the terminal device is
8
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
I I Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
located at the edge of the coverage of the currently serving cell, and may detect one
or more neighbor cells at the same time. These neighbor cells may belong to
different candidate base stations which may support various carrier aggregation
manners. With the different carrier aggregation manners, these neighbor cells may
5 present different characteristics. In the embodiment shown in Figure 1, the terminal
device selects a part or all of the neighbor cells as the object to be measured, based
on the different characteristics of these neighbor cells under the different carrier
aggregation manners.
[43] As shown in Figure 1, the method may include step 103, step 109 and step 115.
10 [44] In step 103, based on the detected carrier aggregation manners of one or more
neighbor cells, one or more are selected from one or more neighbor cells, as the
objects to be measured. In other words, the objects to be measured are selected by
using the different characteristics of these neighbor cells under different carrier
aggregation manners, rather than simply measuring all the neighbor cells. As an
15 example, the selection of the object to be measured may be performed by the source
base station of the terminal device, and then the result of the selection may be
notified to the terminal device by the source base station; as another example, the
selection of the object to be measured may be performed by the terminal device.
[45] In step 109, the terminal device measures the performances of one or more
20 objects to be measured obtained at step 103, to obtain one or more measurement
results. In step 115, the terminal device forms the performance measurement report
of one or more neighbor cells by using these measurement results, and transmits the
performance measurement report to the source base station.
[46] By using the method shown in Figure 1, the number of cells to be measured
25 may be reduced, thereby reducing the measurement load of the terminal device and
improving the processing speed.
[47] It shall be noted that the terminal device may measure the performance of a
cell by using any appropriate method and the performance of a cell may be
characterized by any one or more appropriate performance parameters, as the
30 measurement result of the cell. In the disclosure the description of the particular
measuring method and performance parameters is omitted. The measured
performance parameters of a cell are collectively referred to as the performance of
9
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref: 0P1211-06-0477
EN Translation of PCX Spec
the cell.
[48] Figure 2 shows a method of selecting an object to be measured from one or
more neighbor cells according to another embodiment of the invention. In
consecutive carrier aggregation scenario, the component carriers (CCs)
5 corresponding to the neighbor cells belonging to a candidate base station are located
in the same frequency band, and thus these component carriers have similar
propagation characteristics. By using such characteristics, one neighbor cell may be
selected from the neighbor cells belonging to the candidate base station, as the
object to be measured. The measurement result of the object may be used as the
10 measurement result of all the neighbor cells belong to the candidate base station.
[49] As shown in Figure 2, in step 103-1, it is determined whether the component
carriers corresponding to the neighbor cells belonging to the same base station
among one or more neighbor cells are located in the same frequency band. That is, it
is judged first whether the neighbor cells belonging to the same base station are of
15 consecutive carrier aggregation manner. If yes, in step 103-2 one or more (preferably,
one) are selected from the neighbor cells belonging to the same base station, as the
objects to be measured. If not, in step 103-3 all of the neighbor cells belonging to the
same base station are determined as the objects to be measured. Particularly, if only
one neighbor cell belongs to a candidate base station, this neighbor cell is
20 determined as the object to be measured. If a plurality of neighbor cells belongs to a
candidate base station and these neighbor cells are in different frequency bands, all
the neighbor cells belonging to the candidate base station are determined as the
objects to be measured. If a plurality of neighbor cells belongs to a candidate base
station and these neighbor cells are in the same frequency bands, it is not necessary
25 to use all the neighbor cells belonging to the candidate base station as the objects to
be measured. The steps in Figure 2 may be performed by a terminal device that
performs cell hand over or may be performed by the source base station of the
terminal device.
[50] In the embodiment of Figure 2, the spectrum features and propagation features
30 of the cell in consecutive carrier aggregation manner are taken advantage of to
reduce the number of neighbor cells to be measured, thereby significantly reduce the
measurement load of the terminal device. In other embodiment or example, the
10
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
object to be measured may be selected by using other appropriate characteristics of a
neighbor cell in other type of carrier aggregation manner, which are not numerated
herein.
[51] It shall be noted that the above method of selecting an object to be measured
5 may be applied to other embodiments of the method for cell handover described
above and to be described below.
[52] In some embodiments, before sending the measurement results to the source
base station, the terminal device may further perform a selection among these
measurement results according to some conditions. Only the measurement results
10 which meet the conditions will be sent to the source base station. In this way the
number of measurement results to be processed by the communication system may
be reduced, thereby reducing the transmission load on the communication channel
and the processing load of the source base station. Figures 3-6 respectively shows
some particular embodiments of the method of optimizing the measurement results
15 by the terminal device.
[53] In the embodiment of Figure 3, the terminal device sets a transmission
threshold for the measurement results, to reduce the number of measurement reports
to be processed, thereby reducing the transmission load on the communication
channel and the processing load of the source base station. As shown in Figure 3, in
20 step 110 the terminal device determines whether each of one or more measurement
results is higher than a threshold, and if yes, the terminal device transmits the
measurement result to the source base station in step 115, particularly, it may include
the measurement result in the performance measurement report to be transmitted to
the source base station. If a measurement result is lower than the threshold, the
25 terminal device does not send the measurement result to the source base station, e.g.
the measurement result will not be included in the performance measurement report
to be sent to the source base station. It shall be noted that the above threshold may
be set as actual requirements, e.g. may be set based on the measured performance
parameters or the actual communication scenarios, the description of which is
30 omitted herein. As an example, the above threshold may be a value set for the
terminal device by the system or base station, or may be a value determined by the
terminal device based on the actual application scenario. As another example, the
11
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
• Our Ref: 0P1211-06-0477
EN Translation of PCX Spec
above threshold may be pre-provided in the terminal device.
[54] In the embodiment shown in Figure 4, the terminal device or its source base
station specifies the object to be compared with the measurement results based on
the carrier aggregation manner of the source base station, so that the method of
5 selecting the measurement results may be adapted to the actual communication
scenario. In addition the transmission of the measurement report may be optimized.
Particularly, when the source base station is of consecutive carrier aggregation
manner, due to the similar propagation characteristics of the component carriers in
the same frequency band, any one of the cells of the source base station may be used
10 as the object to be compared and may be measured, thereby reducing the
measurement and processing load of the terminal device and improving the
processing speed. In the case that the source base station is of non-consecutive
carrier aggregation manner, the propagation characteristics of the cells are different
from each other since the component carriers of the cells are located in different
15 frequency bands. In this case, all the cells of the source base station may be used as
the objects to be compared and may be measured. As shown in Figure 4, in step 111
the terminal device or the source base station determines whether the component
carriers corresponding to all the cells of the source base station (or all the cells to
which the terminal device is connected) are located in different frequency bands.
20 [55] If the determining result of step 111 is YES, in step 112 the terminal device
compares each measurement result with the performances of all the cells of the
source base station, or compares each measurement result with a threshold value
(Similar to the embodiment shown in Figure 3" the threshold value may be
predetermined by the system, or the base station or the terminal device, or may be
25 determined based on actual application scenario by the system, or the base station or
the terminal device, the description of which is omitted herein). If a measurement
result is better than the performances of all the cells of the source base station or is
higher than the threshold value, in step 115 the terminal device may send the
measurement result to the source base station, otherwise, the terminal device does
30 not send the measurement result to the source base station.
[56] If the determining result of step 111 is NO, i.e. if the component carriers
corresponding to al the cells of the source base station are located in the same
12
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
" Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
frequency band, in step 112 the terminal device compares each measurement result
with the performance of any of all the cells of the source base station, or may
compare each measurement result with a threshold value ((Similar to the
embodiment shown in Figure 3, the threshold value may be predetermined by the
5 system, or the base station or the terminal device, or may be determined based on
actual application scenario by the system, or the base station or the terminal device,
the description of which is omitted herein). If a measurement result is better than the
performance of any cell randomly selected from all the cells of the source base
station or is higher than the threshold value, in step 115 the terminal device may
10 send the measurement result to the source base station, otherwise, the terminal
device does not send the measurement result to the source base station.
[57] As an example, the terminal device may compare a measurement result with
the performances of the cells of the source base station by using the following
method shown in Figure 5 or Figure 6.
15 [58] As shown in Figure 5, the method of comparing a measurement result of a
neighbor cell with the performances of all the cells of the source base station (step
112 as shown in Figure 4) may include steps 112-1 and 112-2. In step 112-1, one cell
which has the best performance among all the cells of the source base station (all the
cells of the source base station to which the terminal device is connected) is used as
20 the object to be compared. The terminal device measures the performance of the
object to be compared. In step 112-2, the terminal device compares each
measurement result with the performance of the cell having the best performance.
By using the method of Figure 5, the terminal device needs not to compare the
measurement results with the performances of all the cells of the source base station.
25 In this way, the processing load of the terminal device is reduced and processing
speed is improved. As an example, the cell having the best performance among all
the cells to which the terminal device is currently cormected may be specified by the
source base station, e.g. based on the performance data stored in the base station,
and may be notified to the terminal device by the source base station. As another
30 example, the terminal device may select the cell having the best performance from
all the cells to which it is connected based on the performance data stored by the
terminal device or based on the history measurement result stored by it, or
alternatively, the terminal device may measure all the cells to which it is currently
13
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
connected, and select one having the best performance there from as the object to be
compared.
[59] As shown in Figure 6, the method of comparing a measurement result of a
neighbor cell with the performance of any one cell of the source base station (i.e.
5 step 113 shown in Figure 4) may include steps 113-1 and 113-2. In step 113-1, one
cell is randomly selected from all the cells of the source base station (all the cells to
which the terminal device is currently connected) as an object to be compared. The
performance of the object may be measured. In step 113-2, the terminal device
compares each measurement result with the performance of the randomly selected
10 cell. By using the method of Figure 6, the terminal device needs to measure only the
performance of one cell of the source base station. In this way the measurement and
processing load of the terminal device can be reduced and the processing speed can
be improved. As an example, the source base station may randomly specify one of
all the cells, to which the terminal device is currently connected, as the object to be
15 compared, and notify the specified object to the terminal device. As another example,
the terminal device may randomly select one cell fi^om all the cells, to which the
terminal device is currently connected, as the object to be compared.
[60] It shall be noted that the methods of processing the measurement results in the
embodiments/examples in Figures 3-6 may be applied to other embodiments of the
20 method for cell handover of the disclosure.
[61] Figure 7 and Figure 8 each show an apparatus which realizes the method
shown in the above embodiments/example. The apparatus 700 or 800 shown in
Figure 7 or Figure 8 may be configured in a terminal device (not shown) of a
communication system supporting carrier aggregation.
25 [62] As shown in Figure 7, the apparatus for cell handover 700 includes a
measurement object selecting device 701, a cell measuring device 702 and a
transmitting device 703.
[63] When the terminal device moves to the edge of the coverage of the currently
serving cell, the measurement object selecting device 701 is configured to select one
30 or more from one or more detected neighbor cells based on the carrier aggregation
manners of the one or more detected neighbor cells, as the objects to be measured.
[64] The cell measuring device 702 is configured to measure the performances of
14
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
the one or more selected objects to be measured, to obtain one or more measurement
results. The transmitting device 703 is configured to form a performance
measurement report of the one or more neighbor cells based on measurement results
obtained by the cell measuring device 702, and transmit the performance
5 measurement report to the source base station currently serving the terminal device.
[65] Similar to the method embodiment of Figure 1, the apparatus 700 selects the
objects to be measured by using the different characteristics of the detected neighbor
cells, in stead of simply measuring all the neighbor cells. In this way, the number of
cells to be measured may be reduced, thereby reducing the measurement load of the
10 terminal device and improving the processing speed.
[66] As shown in Figure 8, the apparatus 800 for cell handover includes a
measurement object selecting device 801, a cell measuring device 802 and a
transmitting device 803. The difference from that shown in Figure 7 lies in that, the
apparatus 800 for cell handover further includes a judging device 804.
15 [67] The measurement object selecting device 801, the cell measuring device 802
and the transmitting device 803 are respectively similar to those devices 701, 702,
and 703 in Figure 7, the description of which is not repeated. The judging device
804 is configured to judge whether each measurement result obtained by the cell
measuring device 801 is higher than a threshold value, and if yes, instruct the
20 transmitting device 803 to transmit the measurement result to the source base station,
otherwise, do not instruct the transmitting device 803 to transmit the measurement
result to the source base station.
[68] In the embodiment of Figure 8, the apparatus 800 sets a transmission threshold
for the measurement results, in order to reduce the number of measurement reports
25 to be processed, thereby reducing the transmission load on the transmission channel
and the processing load of the source base station.
[69] In another embodiment, the judging device 804 may further select the object to
be compared with the measurement results according to the carrier aggregation
manner of the source base station. Particularly, the judging device 804 may firstly
30 determine whether the component carriers corresponding to all the cells of the
source base station are located in different frequency bands. If the component
carriers corresponding to all the cells of the source base station are located in
15
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
different frequency bands, the judging device 804 fiirther judges whether each
measurement result obtained by the cell measuring device 802 is better than the
performances of all the cells of the source base station or is higher than a threshold
value, and if yes, instructs the transmitting device 803 to transmit the measurement
5 result to the source base station, otherwise, does not instruct to transmit the
measurement result to the source base station. If it is determined that the component
carriers corresponding to all the cells of the source base station are located in the
same frequency band, the judging device further judges whether each measurement
result obtained by the cell measuring device 802 is better than the performance of a
10 cell randomly selected from all the cells of the source base station or is higher than a
threshold value, and if yes, instructs the transmitting device 803 to transmit the
measurement result to the source base station, otherwise, does not instruct to
transmit the measurement result to the source base station. In this way, the selection
of the measurement results may be adapted to the actual communication scenario,
15 thereby further optimizing the transmission of the measurement report. In the case of
consecutive carrier aggregation manner, any one cell is selected randomly form the
cells of the source base station as the object t be compared and is measured, which
may reduce the measurement and processing load of the terminal device and
improve the processing speed.
20 [70] As an example, the apparatus 800 may compare a measurement result with the
performances of the cells of the source base station by using the above method
shown in Figure 5 or Figure 6. For example, the cell measuring device 802 may
measure the performances of all the cells of the source base station and return the
results to the judging device 804. The judging device 804 may select one cell having
25 the best performance from all the cells of the source base station based on the
performances of all the cells measured by the cell measuring device, and compare
each measurement result with the performance of the cell having the best
performance. In this way, the apparatus 800 needs not to compare the measurement
results with the performances of all the cells of the source base station. Thus the
30 processing load of the apparatus can be reduced and the processing speed can be
accelerated. For another example, the cell measuring device 802 may measure the
performance of a cell randomly selected from all the cells of the source base station;
and the judging device 804 may compare the measurement results of the neighbor
16
Sony China Ref.: CNPA10034rN00
^ Sony Ref.: SP301383IN00
# Our Ref.: OP 1211-06-0477
EN Translation of PCT Spec
cells with the performance of the randomly selected cell. In this way, the apparatus
800 needs only to measure the performance of one cell of the source base station.
Thus, the measurement and processing load can be reduced and the processing speed
can be accelerated.
5 [71] Similar to the above method embodiments and examples, in the above
apparatus embodiments and examples the threshold value may be set by the system
(or base station) or by the terminal device as practical requirements, the description
of which is not repeated.
[72] Similar to the above method embodiments, the apparatus 700 or 800 may
10 measure the performance of a cell by using any appropriate method and the
performance of the cell may be characterized by any appropriate performance
parameters, the description of which is omitted herein.
[73] As an example, the measurement object selecting device 701 or 801 may
further judge the component carriers corresponding to the neighbor cells belonging
15 to the same base station among the one or more detected neighbor cells are located
in different frequency bands; and if yes, select one neighbor cell randomly as the
object to be measured, otherwise, use all the neighbor cells belonging to the same
base station as the object to be measured. In this example, the spectrum
characteristic and propagation characteristic of the cells of the consecutive carrier
20 aggregation manner are taken into account, to reduce the number of neighbor cells to
be measured, and thus reduce the measurement load of the terminal device. In other
embodiment or example, the measurement object selecting device 701 or 801 may
select the objects to be measured by using other appropriate characteristics of the
neighbor cells in other types of CA scenarios, which are not numerated herein
25 [74] Some embodiments of the invention further provide terminal devices in the
communication system supporting carrier aggregation. The terminal device may
include the apparatus for cell handover in the above embodiments or examples, or
may use the method of cell handover in the above embodiments or examples, the
description of which is not repeated.
30 [75] In addition, in the embodiments described above with reference to Figures 7-8,
the object to be measured is selected at the side of the terminal device. Selecting the
object to be measured by the terminal device (in stead of the source base station) can
17
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref: 0P1211-06-0477
EN Translation of PCT Spec
reduce the communication overhead between the base station and the terminal
device, and thus the processing speed and efficiency can be improved. According to
another embodiment, there is provided a base station (not shown) including the
above apparatus for cell handover, the apparatus for cell handover of the base station
5 may include a measurement object determining device which is configured to select
one or more from one or more neighbor cells detected by a terminal device served
by the base station based on the carrier aggregation manners of the one or more
neighbor cells, as the objects to be measured. Accordingly, the embodiment further
provides a method of cell handover at the side of the base station. The method may
10 include: selecting one or more from one or more neighbor cells detected by a
terminal device served by the base station based on the carrier aggregation manners
of the one or more neighbor cells, as the objects to be measured; and notifying the
objects to be measured to the terminal device. Particularly, the base station (for
example, by using the measurement object determining device) firstly determines
15 whether the component carriers corresponding to the neighbor cells belonging to the
same base station among the one or more neighbor cells are located in the same
frequency band; if yes, selects one or more (preferably, one) from the neighbor cells
belonging to the same base station as the objects to be measured, if not, uses all the
neighbor cells belonging to the same base station as the objects to be measured.
20 Then the transmitting device of the base station notifies the objects to be measured
to the terminal device. As an example, the measurement object determining device
may be incorporated in the apparatus for cell handover at the base station side
according to the embodiments or examples to be described blow. In addition, the
method of selecting an object to be measured by a base station may be incorporated
25 in the method for cell handover performed at the base station side according to the
embodiments or examples to be described blow.
[76] The methods and apparatuses of selecting a destination base station and a cell
to be accessed at the base station side in the communication system supporting
30 carrier aggregation, as well as a base station and a communication system including
such an apparatus.
[77] In conventional single carrier communication system, a terminal device is
18
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
connected to only one cell at the same time. When performing cell handover, a
unique cell to be accessed can be determined based only on the measurement report
of the neighbor cells, i.e. the unique destination base station can be determined. In
the CA supporting scenarios, before performing cell handover, the terminal device
5 may be connected to a plurality of cells at the same time and these cells correspond
to a same source base station. After the cell handover is performed, the terminal
device may be still connected to a plurality of cells at the same time. If the cells to
be accessed are selected based on only the performances of the neighbor cells, there
is a possibility that the selected cells may belong to different base stations. Some
10 embodiments of the invention provide a policy or scheme of selecting the
destination base station and the cells to be accessed by the source base station in the
CA supporting scenario.
[78] Figure 9 shows an embodiment which illustrates a method of selecting a
destination base station and cells to be accessed by a base station (referred to as the
15 source base station) in the communication system supporting carrier aggregation
according to the performance measurement report of the neighbor cells of a terminal
device served by the base station transmitted by the terminal device.
[79] As shown in Figure 9, the method includes steps 903, 908 and 915. In step 903,
the source base station receives the performance measurement report of the neighbor
20 cells of a terminal device served by the base station transmitted by the terminal
device. The performance measurement report may include the measurement results
of one or more neighbor cells obtained by the terminal device. These neighbor cells
may correspond to one or more candidate base stations. The source base station may
select different algorithms based on the different carrier aggregation manners of the
25 different candidate base stations, to calculate the priorities of these candidate base
stations. Then in step 909, the source base station select one having the highest
priority from these candidate base stations based on the calculated priorities, as the
destination base station. In step 915, the source base station selects one or more from
all the cells belonging to the destination base station in the one or more neighbor
30 cells, as the cells to be accessed of the terminal device.
[80] Since the candidate base stations may support different carrier aggregation
manners, the neighbor cells thereof may present different characteristics. In the
19
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
embodiment shown in Figure 9, the source base station adaptively selects the
algorithm of calculating the priorities based on the carrier aggregation manners of
these neighbor cells. In this way the selection of the destination base station may be
more adapted to the actual communication scenario. In addition, in the method the
5 destination base station is determined first and the cells to be accessed are then
selected from the cells of the destination base station. In this way, the case that the
selected cells to be accessed belong to different base stations can be avoided.
[81] Figure 10 shows a particular embodiment of selecting different priority
calculating algorithms according to the carrier aggregation scenarios of the
10 candidate base stations.
[82] As shown in Figure 10, the method of selecting different priority calculating
algorithms according to the carrier aggregation scenarios (e.g. step 903) may include
steps 903-1, 903-2 and 903-3. In step 903-1, the source base station firstly judges
whether the component carriers corresponding to the neighbor cells belonging to the
15 same candidate base station among the one or more neighbor cells related to the
performance measurement report are located in the same frequency bands. As
described above, these neighbor cells may correspond to one or more candidate base
stations.
[83] If more than one neighbor cell corresponds to the same candidate base station
20 and these neighbor cells are provided in the same frequency band, in step 903-2 the
source base station calculates the priority of the candidate base station based on the
performances of all the neighbor cells belonging to the candidate base station (If
only one neighbor cell corresponds to a candidate base station, the priority of the
candidate base station may be determined based on the performance of this neighbor
25 cell). As an example, the source base station may calculate the sum of the
performances of all the neighbor cells belonging to the candidate base station based
on the measurement results in the performance measurement report, or may weight
the performances of all the neighbor cells belonging to the candidate base station
and then calculate the sum of the weighted performances. Then the source base
30 station may determine the priority of the candidate base station based on the value of
the calculated sum. The larger the sum is, the higher the priority is. It shall be noted
that the weights may be determined according to the functions of the neighbor cells
20
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
and the actual application scenario, the description of which is not detailed herein.
[84] If more than one neighbor cell corresponds to the same candidate base station
and these neighbor cells are provided in different frequency bands, in step 903-3 the
source base station determines the priority of the candidate base station based on the
5 performance of one neighbor cell having the best performance among all the
neighbor cells belonging to the candidate base station in the performance
measurement report. The higher the performance of the neighbor cell having the best
performance is, the higher the priority of the candidate base station is.
[85] In the embodiment of Figure 10, different methods of calculating priorities are
10 selected based on whether or not the consecutive CA scenario or non-consecutive
CA scenario is involved, to obtain the priorities of the candidate base stations.
[86] In CA supporting scenario, the selected destination base station may support
CA. Thus, the terminal device, after being handed over to the destination base
station, may be connected to a plurality of cells. As an example, all the cells of the
15 destination base station may be selected as the cells to be accessed for the terminal
device. As another example, all the neighbor cells belonging to the destination base
station in the one or more neighbor cells may be selected as the cells to be accessed
for the terminal device, or one or more may be selected from all the neighbor cells
belonging to the destination base station in the one or more neighbor cells, as the
20 cells to be accessed for the terminal device. Figures 11-12 each shows another
particular example of selecting the cells to be accessed by using different manners
based on the different CA supporting scenarios.
[87] As shown in Figure 11, the method of selecting the cells to be accessed from
the cells of the destination base station (e.g. step 915) may include steps 915-1,
25 915-2 and 915-3. In step 915-1 the source base station determines whether or not the
component carriers corresponding to all the cells belonging to the destination base
station among one or more neighbor cells involved in the performance measurement
report are provided in the same frequency band, that is, determines whether the
carrier aggregation maimer of the destination base station is non-consecutive or not.
30 [88] If determining that the component carriers corresponding to all the neighbor
cells belonging to the destination base station are provided in the same frequency
band, in step 915-2 the source base station selects one or more neighbor cells from
21
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
all the neighbor cells belonging to the destination base station, as the cells to be
accessed. If only one neighbor cell belongs to the destination base station, this
neighbor cell is determined as the cell to be accessed.
[89] If determining that the component carriers corresponding to all the neighbor
5 cells belonging to the destination base station are provided in different frequency
bands, in step 915-3 the source base station selects one or more neighbor cells from
all the neighbor cells belonging to the destination base station, as the cells to be
accessed. For example, the source base station the source base station may select
one or more neighbor cells provided in the same frequency band from all the
10 neighbor cells belonging to the destination base station, as the cells to be accessed;
or, the source base station may select one or more neighbor cells provided in
different frequency bands based on the practical requirements, as the cells to be
accessed.
[90] As an example, after selecting one or more cells to be accessed, e.g. after the
15 step 915, the source base station may select one from the selected cells to be
accessed as the primary cell to be accessed, as shown by the dotted line block 916 in
Figure 11. The primary cell to be accessed refers to the first cell to which the
terminal device is connected to in the case that there is a plurality of cells to be
accessed when performing cell handover. The terminal device may be connected to
20 the primary cell firstly. After being connected to the primary cell, the terminal
device may be cormected to the other cells to be accessed by adding or actuating
component carriers. For example, the component carriers corresponding to other
cells to be accessed may be added by using RRC connection reconfiguration manner
excluding mobile control message, so as to realize the CA transmission mode with a
25 relatively small overhead.
[91] Figure 12 shows an example of selecting the primary cell to be accessed based
on the CA scenarios. As shown in Figure 12, the method of selecting one primary
cell to be accessed from a plurality of cells to be accessed (e.g. step 916) includes
steps 916-1, 916-2 and 916-3. In step 916-1, the source base station judges, among
30 the selected one or more cells to be accessed determined by using the performance
measurement report, whether there is a cell whose component carriers are in the
same frequency band as the component carriers corresponding to the currently
22
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
serving cell of the terminal device. If there is such a cell, in step 916-2 the cell is
selected as the primary cell to be accessed. If there is not such a cell, in step 916-3
one having the best performance may be selected from all the cells to be accessed
based on the performance measurement report, as the primary cell to be accessed.
5 [92] In the example shovm in Figure 12, the cell whose frequency is the same with
that of the currently serving cell of the terminal device is selected as the primary cell
to be accessed as far as possible. In this way, the handover overhead resulted from
the inconsistency between frequencies of the cell before handover and the cell after
the handover may be reduced, thereby further reducing the interrupt time of the
10 communication.
[93] As an example, the other cells to be accessed may be connected to the terminal
device by adding a carrier using RRC (Radio Source Control) connection
reconfigure manner excluding mobile control information. In this way, the CA
transmission may be realized with a relatively small overhead. It shall be noted that
15 there are two types of RRC connection reconfigure manners. The first type is a
reconfigure containing mobile control information, i.e. handover. The second type is
a reconfigure excluding mobile control information. In the handover manner (i.e. the
first type), MAC (IVIedia Access Control) layer, PDCP (Packet Data Convergence
Protocol) layer, and RLC (Radio Link Control) layer all need to be reconfigured, and
20 the security key needs also to be reconfigured. This results in a large overhead. In
contrast, the second type needs not to reconfigure the above fimctions, and thus
brings about a relatively small overhead.
[94] In another example, the source base station may select one having the best
performance from all the neighbor cells belonging to the destination base station
25 (or from the cells to be accessed selected by the source base station) based on the
performance measurement report, as the primary cell to be accessed.
[95] Figure 13 shows another method for cell handover according to another
embodiment of the invention. As shown in Figure 13, after determining the
destination base station and the cells to be accessed (It shall be noted that the
30 destination base station and the cells to be accessed can be determined by using the
method in the above embodiments or examples), the process of the source base
station forming a handover command and transmitting the handover command may
23
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383INOO
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
include steps 917, 919, 921 and 923.
[96] In step 917, the source base station judges whether the component carriers
corresponding to the one or more selected cells to be accessed are provided in the
same frequency band. If yes, in step 919 the source base station packages the
5 configuration information of all the cells to be accessed in a handover command
indicating initiation of cell handover of the terminal device. Otherwise, in step 921
the source base station packages the configuration information of only the primary
cell to be accessed in the handover command. Finally in step 923, the source base
station transmits the handover command to the destination base station.
10 [97] In the method of Figure 13, if the number of the selected cells to be accessed is
larger than 1 and the component carriers corresponding to these cells to be accessed
are provided in the same frequency band, the source base station packages the
information of all the cells to be accessed in the handover command. Thus, the
terminal device can be connected to all the cells to be accessed at a time. That is,
15 after being handed over, the terminal device can enter the CA mode directly. If the
terminal device uses CA communication mode before being handed over, the quality
of service for the user can be ensured since the differences between the qualities of
service before and after the handover can be reduced. If the number of selected
cells to be accessed is larger than 1 and the component carriers corresponding to
20 these cells to be accessed are provided in different frequency bands, the terminal
device can firstly be connected to the primary cell. After being connected to the
primary cell, the terminal device may be connected to the other cells to be accessed
by adding component carriers, for example, the component carriers corresponding to
the other cells to be accessed can be added by using RRC connection reconfigure
25 manner excluding mobile control information, thereby the CA transmission mode
can be realized with a relatively small overhead. If the selected primary cell to be
accessed corresponds to component carriers that are in the same frequency band as
those in the serving cell of the terminal device before the handover, the overhead
due to the inconsistency between frequencies before and after the handover can be
30 fijrther reduced, thereby the interrupt time of the communication can be fijrther
shortened.
[98] As an example, if the terminal device is currently connected to a plurality of
24
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: OP 1211-06-0477
EN Translation of PCT Spec
cells of the source base station, the terminal device may be kept in communication
with one of the plurality of cells to which it is currently connected to before the
handover is completed. In conventional single carrier communication system (such
as LTE system), a hard handover method is generally employed for cell handover.
5 That is, during the handover the terminal device will disconnect its communication
with the old cell first before being connected to the new cell, which inevitably
results in communication interruption; thereby the quality of service for the user
may be decreased. In the example, the disadvantages of CA communication are
used, that is, the terminal device may keep in communication with one or more old
10 cells before being connected to the new cell. The communication with the old cells
is disconnected after the terminal device is completely connected to the new cell.
This can significantly reduce the interruption time of communication, and can
improve the quality of service experienced by the user.
[99] Figure 15 shows a method for cell handover in a communication system
15 supporting carrier aggregation according to another embodiment of the invention.
The method is performed by the source base station in the communication system.
[100] As shown in Figure 15, the method may include steps 1517, 1519, 1521 and
1523. In step 1517, after selecting a destination base station and one or more cells to
be accessed for a terminal device which is served by the source base station and is to
20 be handed over, the source base station determines whether the component carriers
corresponding to the selected cells to be accessed are provided in the same
frequency band. If yes, in step 1519 the source base station packages the
configuration information of all the cells to be accessed in a handover command
indicating to initiate the handover for the terminal device. Otherwise, in step 1521
25 the source base station packages the configuration information of only part (one or
several cells) of the cells to be accessed in the handover command. Finally in step
1523, the handover command is transmitted. By using this method, in the case that
the cells to be accessed are of consecutive CA mode, the terminal device can be
connected to all the cells to be accessed at a time, that is, the terminal device can
30 enter CA mode directly after the handover. In the case that the terminal device is in
CA communication mode before the handover, the quality of service for the user can
be ensured since the differences in qualities of service before and after the handover
can be reduced.
25
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref.: OP 1211-06-0477
EN Translation of PCT Spec
[101] Figure 20 shows a method for cell handover in a communication system
supporting carrier aggregation according to another embodiment of the invention.
The method is similar to that in Figure 15; the difference lies in that the method of
Figure 20 may further include a step 2016 of selecting a primary cell to be accessed.
5 [102] As shown in Figure 20, the method may include steps 2016, 2017, 2019, 2021
and 2023. Steps 2017, 2019, 2021 and 2023 are respectively similar to steps 1517,
1519, 1521 and 1523 shown in Figure 15, the description of which is omitted herein.
In step 2016, the source base station may select one from the one or more selected
cells to be accessed, as the primary cell to be accessed. In the example, the source
10 base station may package the configuration information of only the primary cell to
be accessed in the handover command in step 2021. It shall be noted that the
primary cell to be accessed can be selected by using the method shown in the above
embodiments or examples, the description of which is not repeated.
[103] As an example, the method shown in Figure 15 or 20 may further include steps
15 of selecting by the source base station the destination base station and the cells to be
accessed, such as steps 2009 and 2015 shown in Figure 20. For example, in steps
2009 and 2015, the source base station selects a destination base station from the
candidate base stations corresponding to the neighbor cells of the terminal device
and then selects one or more cells to be accessed from the cells of the destination
20 base station, based on the performance measurement report transmitted from the
terminal device. It shall be noted that the source base station may select the
destination base station and the cells to be accessed by using any appropriate method,
such as the method in the embodiments or examples described above with reference
to Figures 9-13, the description of which is not repeated.
25 [104] Figure 14 and Figure 16 each show an embodiment or example of an apparatus
for cell handover in the CA supporting scenario. The apparatus shown in Figure 14
or 16 is configured in the base station of the communication system supporting
carrier aggregation. The devices represented by dotted line blocks in the Figures are
optional.
30 [105] In the embodiment of Figure 14, the apparatus for cell handover 1400 may
include a receiving device 1401, a priority determining device 1402, a destination
base station selecting device 1403 and a cell selecting device 1404. The receiving
26
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
device 1400 is configured to receive the performance measurement report of one or
more neighbor cells transmitted from a terminal device served by the base station.
The priority determining device 1402 is configure to select different algorithms for
calculating the priorities of the candidate base stations based on the performance
5 measurement report and based on the carrier aggregation manners of one or more
candidate base stations corresponding to the one or more neighbor cells. The
destination base station selecting device 1403 may select one corresponding to the
highest priority among the candidate base stations based on the priorities thereof
calculated by the priority determining device 1402, as the destination base station.
10 The cell selecting device 1404 selects one or more cells to be accessed for the
terminal device from the cells belonging to the destination base station.
[106] Since the candidate base stations may support different carrier aggregation
manners, the neighbor cells thereof may present different characteristics. In the
above example, the apparatus in the source base station adaptively selects different
15 algorithms for calculating the priorities based on the carrier aggregation manners of
these neighbor cells. In this way, the selection of the destination base station can be
more adapted to the actual communication scenario. In addition, the apparatus
determines the destination base station first, and then selects the cells to be accessed
from the cells of the destination base station, which avoids the case that the selected
20 cells to be accessed belong to different base stations.
[107] As a particular example of the embodiment, the priority determining device
1402 may firstly judge whether the candidate base station is of consecutive CA
mode or non-consecutive CA mode and select an algorithm adapted to the
consecutive or non-consecutive CA mode. Particularly, the priority determining
25 device 1402 may judge whether the component carriers corresponding to the
neighbor cells belonging to the same candidate base station among the one or more
neighbor cells are provided in the same frequency band.
[108] If more than one neighbor cell corresponds to the same candidate base station
and these neighbor cells are provided in the same frequency band, the priority
30 determining device 1402 may calculate the priority of the candidate base station
according to the performances of all the neighbor cells belonging to the candidate
base station (if only one neighbor cell corresponds to a candidate base station, the
27
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
priority of the candidate base station may be determined base on the performance of
the neighbor cell). As an example, the sum of the performances of the entire
neighbor cells belonging to the candidate base station may be calculated based on
the measurement results in the performance measurement report, or the
5 performances of all the neighbor cells belonging to the candidate base station may
be weighted and then the sum of the weighted performances may be calculated.
Then the priority of the candidate base station may be determined based on the value
of the calculated sum. The larger the sum is, the higher the priority is. It shall be
noted that the weights may be determined according to the functions of the neighbor
10 cells and the actual application scenario, the description of which is not repeated.
[109] If more than one neighbor cell corresponds to the same candidate base station
and these neighbor cells are provided in different frequency bands, the priority
determining device 1402 may determine the priority of the candidate base station
based on the performance of one neighbor cell having the best performance among
15 all the neighbor cells belonging to the candidate base station in the performance
measurement report. The higher the performance of the neighbor cell having the best
performance is, the higher the priority of the candidate base station is.
[110] As a particular example, the cell selecting device 1404 may further select one
or more from all the neighbor cells belonging to the destination base station among
20 the one or more neighbor cells involved in the performance measurement report, as
the cells to be accessed. For example, the cell selecting device 1404 may use all the
neighbor cells belonging to the destination base station among the one or more
neighbor cells involved in the performance measurement report, as the cells to be
i
accessed. As another example, the cell selecting device 1404 may select one or more
25 from all the cells belonging to the destination base station, as the cells to be accessed.
As examples, the cell selecting device 1404 may select the cells to be accessed by
using different manners based on the different CA supporting scenarios, with the
method described above with reference to Figures 11-12, which makes the selected
cells to be accessed more suitable to the actual CA supporting scenario.
30 [111] For example, the cell selecting device 1404 may firstly determine whether the
component carriers corresponding to all the neighbor cells belonging to the
destination base station among one or more neighbor cells involved in the
28
•
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
performance measurement report are in the same frequency band. If yes, the cell
selecting device 1404 may select all the neighbor cells belonging to the destination
base station as the cells to be accessed; otherwise, select one or more from the
neighbor cells belonging to the destination base station, as the cells to be accessed. If
5 only one neighbor cell belongs to the destination base station, the neighbor cell is
used as the cell to be accessed.
[112] As an example, the cell selecting device 1404 may further select one from the
selected cells to be accessed as the primary cell to be accessed. For example, the cell
selecting device 1404 may judge, among the selected one or more cells to be
10 accessed, whether there is a cell whose component carriers are in the same
frequency band as the component carriers corresponding to the currently serving cell
of the terminal device; and if there is such a cell, select the cell as the primary cell to
be accessed, otherwise, select one having the best performance from all the neighbor
cells belonging to the destination base station based on the performance
15 measurement report, as the primary cell to be accessed. For another example, after
the destination base station selecting device 1403 selects the destination base station,
the cell selecting device 1404 may fiarther select one having the best performance
from all the neighbor cells belonging to the destination base station, as the primary
cell to be accessed. The cell selecting device 1404 may select the primary cell to be
20 accessed by using the above method in the above embodiments or examples, the
description of which is not repeated.
[113] In another example, the apparatus 1400 may further include a demand forming
device 1405 and a transmitting device 1406. The demand forming device 1405 may
form the handover command by using the method shown in Figure 13. Particularly,
25 the demand forming device 1405 may determine whether the component carriers
corresponding to the selected cells to be accessed are provided in the same
frequency band, if yes, package the configuration information of all the cells to be
accessed in the handover command; otherwise, package the configuration
information of only the primary cell to be accessed in the handover command. The
30 transmitting device 1406 is configured to transmit the handover command to the
destination base station. In the example, if the number of the selected cells to be
accessed is larger than 1 and the component carriers corresponding to these cells to
be accessed are provided in the same frequency band, the terminal device can be
29
Sony China Ref.: CNPA10034IN00
•
Sony Ref: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
connected to all the cells to be accessed at a time. That is, after being handed over,
the terminal device can enter the CA mode directly. If the terminal device uses CA
communication mode before being handed over, the quality of service for the user
can be ensured since the differences between the qualities of service before and after
5 the handover can be reduced. In addition, if the number of selected cells to be
accessed is larger than 1 and the component carriers corresponding to these cells to
be accessed are provided in different frequency bands, the terminal device can firstly
be connected to the primary cell. After being connected to the primary cell, the
terminal device may be connected to the other cells to be accessed by adding
10 component carriers, for example, the component carriers corresponding to the other
cells to be accessed can be added by using RRC connection reconfigure manner
excluding mobile control information, thereby the CA transmission mode can be
realized with a relatively small overhead.
[114] As an example, if the terminal device to be handed over is currently connected
15 to a plurality of cells of the source base station, the terminal device may be kept in
communication with one of the plurality of cells to which it is currently connected to
before the handover is completed. For example, the source base station (e.g. the
transmitting device 1406) may send a command to the terminal device to instruct the I
terminal device to keep in communication with an old cell. Similar to the above
20 embodiments or examples, this can significantly reduce the interruption time of
communication, and can improve the quality of service experienced by the user.
[115] In the embodiment of Figure 16, the apparatus 1600 may perform the method
of Figure 15. Particularly, the apparatus 1600 may include a demand forming device
1605 and a transmitting device 1606.
25 [116] The demand forming device 1605 is configured to determine whether the
component carriers corresponding to the selected cells to be accessed belonging to
the destination base station selected by the present base station for the terminal
device served by the present base station and to be handed over are provided in the
same frequency band. If yes, the demand forming device 1605 packages the
30 configuration information of all the cells to be accessed in a handover command
indicating to initiate the handover for the terminal device. Otherwise, the demand
forming device 1605 packages the configuration information of only part (one or
30
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
" Our Ref.: OP 1211-06-0477
EN Translation of PCT Spec
several cells) of the cells to be accessed in the handover command. The transmitting
device 1606 transmits the handover command to the destination base station. By
using this apparatus, in the case that the cells to be accessed are of consecutive CA
mode, the terminal device can be connected to all the cells to be accessed at a time,
5 that is, the terminal device can enter CA mode directly after the handover. In the
case that the terminal device is in CA communication mode before the handover, the
quality of service for the user can be ensured since the differences in qualities of
service before and after the handover can be reduced.
[117] As an example, the apparatus 1600 for cell handover may include a primary
10 cell selecting device 1607, configured to select one from one or more selected cells
to be accessed, as the primary cell to be accessed. Thus, the demand forming device
may package only the configuration information of the primary cell in the handover
command. In such a case, the terminal device may firstly be connected to the
primary cell. After that, the terminal device may be connected to the other cells to be
15 accessed by adding or actuating component carriers. For example, the component
carriers corresponding to the other cells to be accessed may be added by RRC
connection reconfigure mode excluding the mobile control information, thereby the
CA transmission mode can be realized with a relative small overhead.
[118] Particularly, the primary cell selecting device 1607 may select one having the
20 best performance among the selected cells to be accessed based on the performance
measurement report, as the primary cell to be accessed.
[119] Alternatively, the primary cell selecting device 1607 may select the primary
cell to be accessed, based on the carriers of the selected cells to be accessed.
Particularly, the primary cell selecting device 1607 may judge whether there is a cell,
25 among the selected cells to be accessed, whose corresponding component carriers
are in the same frequency band as the component carriers corresponding to the
currently serving cell of the terminal device, if yes, select this cell as the primary
cell to be accessed, otherwise, select one having the best performance among all the
neighbor cells belong to the destination base station, as the primary cell to be
30 accessed. IF the primary cell to be accessed is provided in the same frequency band
as the currently serving cell of the terminal device, the handover overhead due to the
inconsistency between the frequencies before and after the handover can be reduced,
31
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
thereby the interrupt time of communication can be further reduced.
[120] As an example, the apparatus 1600 for cell handover may further include a
receiving device 1601, a destination base station selecting device 1603 and a cell
selecting device 1604. Similar to the above embodiments or examples, the receiving
5 device 1601 is configured to receive the performance measurement report of one or
more neighbor cells transmitted from the terminal device served by the base station.
The destination base station selecting device 1603 is configure to select one from
one or more candidate base stations corresponding to the one or more neighbor cells,
based on the performance measurement report, as the destination base station. The
10 destination base station selecting device 1603 may select the destination base station
by using the method shown in the above embodiments or examples or any other
appropriate method. For example, the destination base station selecting device 1603
may be similar to the device 1403 in Figure 14, the description of which is not
repeated. The cell selecting device 1604is configured to select one or more cells to
15 be accessed for the terminal device from all the neighbor cells belonging to the
destination base station.
[121] As a particular example, the cell selecting device 1604 may select the cells to
be accessed by using the method shown in the above embodiments or examples. For
example, the cell selecting device 1604 may determine whether the component
20 carriers corresponding to all the neighbor cells belonging to the destination base
station are provided in the same frequency band, if yes, select all the neighbor cells
belonging to the destination base station as the cells to be accessed, otherwise, select
one or more from all the neighbor cells belonging to the destination base station, as
the cells to be accessed.
25 [122] In another particular example, the apparatus 1600 may further include the
priority determining device 1402 as described above with reference to Figure 14, the
function of which is similar to that described above and the description of which is
not repeated.
[123] Some embodiments of the invention provide methods of cell handover under
30 CA supporting scenarios. These methods may include the flows of cell handover
performed by the terminal device and the source base station in the above and below
embodiments or examples, the description of which is not repeated.
32
Sony China Ref.: CNPA10034rN00
^ Sony Ref: SP301383IN00
W Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
[124] Some embodiments of the invention provide a communication system
including the terminal device and/or the base station described in the above and
below embodiments or examples.
.
5 [125] Figure 17, Figure 18, and Figure 19 each show an application scenario to
which the above methods of cell handover may be applied. In the figures, A01-A03,
B01-B03, and C01-A03 respectively represent base stations. In Figure 17, the
coverages of the cells corresponding to the component carriers FAI and FA2 are
substantially overlapped with each other, and can provide similar coverages. FM
10 and FA2 are in the same frequency bands, which belongs to the typical consecutive
carrier aggregation manner. Figure 18 and Figure 19 respectively correspond to
non-consecutive CA scenarios, in which the component carriers FBI and FB2 are in
different frequency bands, and Fci and Fez also are in different frequency bands. The
cell corresponding to FBI or Fci is mainly used to ensure coverage and the cell
15 corresponding to FB2 or Fc2 is mainly used to improve throughput. The difference
between Figure 18 and Figure 19 lies in that, in Figure 19 the antenna of the cell
corresponding to Fc2 is directed to the edge region of the cell corresponding to Fci,
such that the application scenario in Figure 19 can significantly improve the
throughput at the edge region of the cell corresponding to Fci.
20 [126] According to some examples, the process of cell handover may include a
preparation stage, a performing stage and a finishing stage. Different scenarios
correspond to different handover policies. The processes of cell handover in the 3
typical application scenarios are described below
[127] Scenario shown in Figure 17:
25 [128] Preparation stage:
[129] When the terminal device is at the edge of the coverage of the currently
serving cell, it needs to measure all the neighbor cells. A carrier frequency
corresponds to a neighbor cell, if the neighbor cells belonging to the same base
i
station are in the same frequency band; only one neighbor cell is selected and
30 measured. At this time, it is supposed that the measurement result obtained by the
terminal device for the cell corresponding to FAI is denoted asM^i, the measurement
33
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
result for the cell corresponding to FA2 is denoted asM^2, and the measurement
result for a neighbor cell is denoted as M^. If one of the following conditions is
met, the terminal device transmits the measurement result to the base station.
M,>Th, ^
[130] That is, if the measurement result of the neighbor cell is higher than a threshold
( '^ ) or is better than the measurement result of a cell to which the terminal device is
connected to, the terminal device transmits the measurement result to the base
station. That is, the neighbor cell can be used as a candidate destination cell.
10 [131] In actual processing, the base station or the terminal device may randomly
specify one of the cells to which the terminal device is connected, as the object to be
compared with the measurement result of the neighbor cell.
[132] Performing stage:
[133] In this stage the destination base station and the cells to be accessed are
15 determined. Since the carrier frequencies of candidate cells belonging to the same
base station are in the same frequency band, the priority of the base station can be
decided by the weighted performances of these candidate cells. The base station
having the highest priority is selected as the destination base station. Since the
carrier frequencies of candidate cells belonging to the destination base station are in
20 the same frequency band, all the candidate cells are used as the cells to be accessed.
Here, it is supposed that the cells corresponding to FAI and FA2 in the base station
A02 are selected as the cells to be accessed.
[134] Finishing stage:
[135] The terminal device connects to a plurality of cells before handover, the
25 number of the selected cells to be accessed is more than one and the component
carriers corresponding to these cells to be accessed are in the same frequency band.
34
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref.: OP 1211-06-0477
EN Translation of PCX Spec
When sending a handover request, the source base station sends the information of
all the cells to be accessed to the destination base station.
[136] The destination base station performs an access control estimation based on the
received information, and if it allows the terminal device to access, it sends an ACK
5 message to the source base station.
[137] After receiving the ACK message, the source base station transmits an RRC
•
connection reconfigure message containing the mobility control information, to
initiate the RRC connection reconfigure for all the cells to be accessed.
[138] When the reconfigure is completed, the terminal device chooses to disconnect
10 fi-om the one or more original cells, and keeps in communication with at least one
original cell, and sends a synchronization request to all the cells to be accessed to the
destination base station, so as to be synchronized to the new cells.
[139] When the terminal device is synchronized with all the cells to be accessed in
the destination base station and completes the corresponding accessing processes so
15 that it is ready for data transmission, the terminal device disconnects from the
original cell and is completely served by the new base station and cells.
[140] Scenario shown in Figure 18:
[141] Preparation stage: when the terminal device is at the edge of a cell, it needs to
measure all the neighbor cells, one of which corresponds to a carrier frequency. At
20 this time, it is supposed that the measurement result of the terminal device for the
cell corresponding to FBI is denoted asM^i, the measurement result for the cell
corresponding to FB2 is denoted asM^2 5 ^nd the measurement result for a neighbor
cell is denoted asM^. If one of the following conditions is met, the terminal device
transmits the measurement result of the neighbor cell to the base station:
25 ^/^^\or
35
Sony China Ref.: CNPA10034IN00
# Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
[142] That is, if the measurement result of the neighbor cell is higher than a threshold
(^"i) or is better than the measurement result of any cell to which the terminal
device is connected to, the terminal device transmits the measurement result of the
neighbor cell to the base station. That is, the neighbor cell is selected as a candidate
5 cell for handover.
[143] In actual processing, the base station or the terminal device may randomly
specify one of the cells to which the terminal device is connected, as the object to be
compared with the measurement result of the neighbor cell.
[144] Performing stage:
10 [145] In this stage the destination base station and the cells to be accessed are
determined. The priority of the candidate base station can be decided depending
upon whether or not the carrier frequencies of candidate cells belonging to the same
base station are in the same frequency band. The base station having the highest
priority is selected as the destination base station. The cells to be accessed are
15 decided based on the number of candidate cells belonging to the destination base
station, whether or not in the same frequency band, and the relationship with the
carrier frequency before handover. Here it is supposed that the cells corresponding
to FBI and FB2 in the base station B03 are selected as the cells to be accessed.
[146] Finishing stage:
20 [147] It is supposed that the terminal device is connected to only one cell before
handover. The number of the cells to be accessed is more than one, and the
component carriers corresponding to these cells to be accessed are in different
frequency bands. It is also supposed that FBI refers to the frequency of the cell
before the handover. At this time, the cell corresponding to FBI is selected as the
25 primary cell to be accessed, and when sending the handover request, the source base
station sends the information of the primary cell to to the destination base station.
[148] The destination base station performs access control estimation, and if it allows
36
Sony China Ref.: CNPA10034IN00
# Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
the terminal device to access, it sends an ACK message to the source base station.
[149] After receiving the ACK message, the source base station transmits an RRC
connection reconfigure message containing the mobility control information, to
initiate the RRC connection reconfigure for the primary cell to be accessed.
5 [150] When the reconfigure is completed, the terminal device chooses to disconnect
from the original cell, and send a synchronization request to the primary cell to be
accessed to the destination base station, so as to be synchronized to the new cells. I
[151] When the terminal device is synchronized with the primary cell to be accessed
in the destination base station and completes the corresponding accessing processes,
10 it is ready for data transmission. At this time, the terminal device is completely
served by the new base station and cells.
[152] The terminal device initiates an RRC connection reconfigure message
excluding the mobility control information, to add the component carrier FB2, and to
access the cell corresponding to FB2- In this way carrier aggregation is realized.
15 [153] Scenario shown in Figure 19:
[154] Preparation stage:
[155] When the terminal device is at the edge of a cell, it needs to measure all the
neighbor cells, one of which corresponds to a carrier frequency. At this time, it is
supposed that the measurement result of the terminal device for the cell
20 corresponding to Fci is denoted as M^^, the measurement result for the cell
corresponding to Fc2 is denoted asM^2, and the measurement result for a neighbor
cell is denoted asM^. If one of the following conditions is met, the terminal device
transmits the measurement result of the neighbor cell to the base station:
f ^, or
25 Mf>Mf,+Th, ^^ Mf>Mf,+Th,
[156] That is, if the measurement result of the neighbor cell is higher than a threshold
37
Sony China Ref.: CNPA10034IN00
^ Sony Ref: SP301383IN00
W Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
{Ti\) or is better than the measurement results of all the cells to which the terminal
device is connected to, the terminal device transmits the measurement result of the
neighbor cell to the base station. That is, the neighbor cell is selected as a candidate
cell for handover.
5 [157] In actual processing, the base station or the terminal device selects one cell
having the best measurement result, as the object to be compared with the
measurement result of the neighbor cell.
[158] Performing stage:
[159] In this stage the destination base station and the cells to be accessed are
10 determined. Particularly, the priority of the candidate base station can be decided
depending upon whether or not the carrier frequencies of candidate cells belonging
to the same base station are in the same frequency band. The base station having the
highest priority is selected as the destination base station. The cells to be accessed
are decided based on the number of candidate cells belonging to the destination base
15 station, whether or not in the same frequency band, and the relationship with the
carrier frequency before handover. Here it is supposed that the cells corresponding
to Fci and Fc2 in the base station C03 are selected as the cells to be accessed.
[160] Finishing stage:
[161] It is supposed that the terminal device connects to a plurality of cells at the
20 same time before handover, the number of the selected cells to be accessed is more
than one and the component carriers corresponding to these cells to be accessed are
in different frequency bands. When sending a handover request, the source base
station sends the information of all the cells to be accessed to the destination base
station.
25 [162] The destination base station performs access control estimation, and if it allows
the terminal device to access, it sends an ACK message to the source base station.
[163] After receiving the ACK message, the source base station transmits an RRC
connection reconfigure message containing the mobility control information, to
38
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: OP 1211-06-0477
EN Translation of PCX Spec
initiate the RRC connection reconfigure for all the cells to be accessed.
[164] When the reconfigure is completed, the terminal device chooses to disconnect
from one or more original cells, and keeps in communication with at least one
original cell, and sends a synchronization request to all the cells to be accessed to the
5 destination base station, so as to be synchronized to the new cells.
[165] When the terminal device is synchronized with all the cells to be accessed in
the destination base station and completes the corresponding accessing processes so
that it is ready for data transmission, the terminal device disconnects from the
original cell and is completely served by the new base station and cells.
10 [166] It should be understood that the above embodiments and examples are
illustrative, rather than exhaustive. The present disclosure should not be regarded as
being limited to any particular embodiments or examples stated above.
[167] As an example, the components, units or steps in the above apparatuses and
methods can be configured with software, hardware, firmware or any combination
15 thereof in the base station or the terminal device in a communication network, as
part of the base station or the terminal device, by using method or means well
known in the art, the details of which are omitted herein. As an example, the above
methods or apparatus can be realized in existing base station or terminal device in a
communication system, with a modification to the related parts of the existing base
20 station or terminal device.
[168] As an example, in the case of using software or firmware, programs
constituting the software for realizing the above method or apparatus can be
installed to a computer with a specialized hardware structure (e.g. the general
purposed computer as shown in Figure 21) from a storage medium or a network. The
25 computer, when installed with various programs, is capable of carrying out various
functions.
[169] In Figure 21, a central processing unit (CPU) 2101 executes various types of
processing in accordance with programs stored in a read-only memory (ROIVI) 2102,
or programs loaded from a storage unit 2108 into a random access memory (RAM)
30 2103. The RAM 2103 also stores the data required for the CPU 2101 to execute
various types of processing, as required. The CPU 2101, the ROM 2102, and the
39
Sony China Ref.: CNPA10034rN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
RAM 2103 are connected to one another through a bus 2104. The bus 2104 also
connects to an input/output interface 2105.
[170] The input/output interface 2105 connects to an input unit 2106 composed of a
keyboard, a mouse, etc., an output unit 2107 composed of a cathode ray tube or a
5 liquid crystal display, a speaker, etc., the storage unit 2108, which includes a hard
disk, and a communication unit 2109 composed of a modem, a terminal adapter, etc.
The communication unit 2109 performs communicating processing. A drive 2110 is
connected to the input/output interface 2105, if needed. In the drive 2110, for
example, removable media 2111 is loaded as a recording medium containing a
10 program of the present invention. The program is read from the removable media
2111 and is installed into the storage unit 2108, as required.
[171] In the case of using software to realize the above consecutive processing, the
programs constituting the software may be installed from a network such as Internet
or a storage medium such as the removable media 2111.
15 [172] Those skilled in the art should understand the storage medium is not limited to
the removable media 2111, such as, a magnetic disk (including flexible disc), an
optical disc (including compact-disc ROM (CD-ROM) and digital versatile disk
(DVD)), an magneto-optical disc (including an MD (Mini-Disc) (registered
trademark)), or a semiconductor memory, in which the program is recorded and
20 which are distributed to deliver the program to the user aside from a main body of a
device, or the ROM 2102 or the hard disc involved in the storage unit 2108, where
the program is recorded and which are previously mounted on the main body of the
device and delivered to the user.
[173] The present disclosure further provides a program product having
25 machine-readable instruction codes which, when being executed, may carry out the
method for cross phase modulation recovery according to the embodiments.
[174] Accordingly, the storage medium for bearing the program product having the
machine-readable instruction codes is also included in the disclosure. The storage
medium includes but not limited to a flexible disk, an optical disc, a magneto-optical
30 disc, a storage card, or a memory stick, or the like.
[175] In the above description of the embodiments, features described or shown with
respect to one embodiment may be used in one or more other embodiments in a
similar or same manner, or may be combined with the features of the other
40
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCT Spec
embodiments, or may be used to replace the features of the other embodiments.
[176] As used herein, the terms the terms "comprise," "include," "have" and any
variations thereof, are intended to cover a non-exclusive inclusion, such that a
process, method, article, or apparatus that comprises a list of elements is not
5 necessarily limited to those elements, but may include other elements not expressly
listed or inherent to such process, method, article, or apparatus.
[177] Further, in the disclosure the methods are not limited to a process performed in
temporal sequence according to the order described therein, instead, they can be
executed in other temporal sequence, or be executed in parallel or separatively. That
10 is, the executing orders described above should not be regarded as limiting the
method thereto.
[178] While some embodiments and examples have been disclosed above, it should
be noted that these embodiments and examples are only used to illustrate the present
disclosure but not to limit the present disclosure. Various modifications,
15 improvements and equivalents can be made by those skilled in the art without
departing from the scope of the present disclosure. Such modifications,
improvements and equivalents should also be regarded as being covered by the
protection scope of the present disclosure.
41

Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: OP 1211-06-0477
EN Translation of PCX Spec
What is claimed is:
1. A method for cell handover in a communication system supporting carrier
aggregation, comprising:
judging, by a source base station in the communication system, whether
5 component carriers corresponding to one or more cells to be accessed which belong
to a destination base station selected for a terminal device are in a same frequency
band, wherein the terminal device is currently served by the source base station and
is to be handed over, and if yes, packaging configuration information of all the one
or more cells to be accessed in a handover command for initiating cell handover,
10 otherwise, packaging configuration information of one or more of the one or more
cells to be accessed in the handover command; and
transmitting the handover command to the destination base station.
2. The method for cell handover in a communication system of claim 1, further
15 comprising:
selecting one cell from the one or more cells to be accessed, as a primary cell to
be accessed, and
wherein packaging the configuration information of one or more of the one or
more cells to be accessed in the handover command comprises: packaging
20 configuration information of the primary cell to be accessed in the handover
command.
3. The method for cell handover in a communication system of claim 2,
wherein selecting one cell from the one or more cells to be accessed as the primary
25 cell to be accessed comprises:
judging whether there is a cell, among the one or more cells to be accessed,
component carriers of which are in a same frequency band with those corresponding
to a currently serving cell of the terminal device; and if yes, selecting the cell as the
primary cell to be accessed, otherwise, selecting one cell having best performance
30 among the one or more cells to be accessed, as the primary cell to be accessed.
42
Sony China Ref.: CNPA10034IN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
4. The method for cell handover in a communication system of claim 2,
wherein selectmg one cell from the one or more cells to be accessed as the primary
cell to be accessed comprises:
selecting one cell having best performance among the one or more cells to be
5 accessed, as the primary cell to be accessed.
5. The method for cell handover in a communication system of claim 1,
wherein if the terminal device is currently cormected to a plurality of cells of the
source base station, the terminal device keeps in communication with one of the
10 plurality of cells of the source base station before being handed over to the
destination base station.
6. The method for cell handover in a communication system of claim 1, further
comprising:
15 selecting, by the source base station based on a performance measurement
report for one or more neighbor cells of the terminal device transmitted from the
terminal device, a candidate base station from one or more candidate base stations
corresponding to the one or more neighbor cells, as the destination base station; and
selecting one or more cells from all cells belonging to the destination base
20 station in the one or more neighbor cells, as the one or more cells to be assessed for
the terminal device.
7. The method for cell handover in a communication system of claim 6,
wherein selecting a candidate base station from one or more candidate base stations
25 as the destination base station comprising:
selecting an algorithm suitable for carrier aggregation manners of the one or
more candidate base stations to calculate priorities of the one or more candidate base
stations, based on the performance measurement report and based on the carrier
aggregation manners of the one or more candidate base stations; and
30 selecting one candidate base station having a highest priority from the one or
more candidate base stations, as the destination base station.
43
Sony China Ref.: CNPA10034rN00
•
Sony Ref.: SP301383IN00
Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
8. The method for cell handover in a communication system of claim 7,
wherein calculating priorities of the one or more candidate base stations comprises:
judging whether component carriers corresponding to all neighbor cells
5 belonging to a same candidate base station in the one or more neighbor cells are in a
same frequency band; and if yes, calculating priority of the candidate base station
according to performances of all the neighbor cells belonging to the candidate base
station, otherwise, calculating the priority of the candidate base station according to
performance one having best performance of all the neighbor cells belonging to the
10 candidate base station.
9. The method for cell handover in a communication system of claim 8,
wherein calculating the priority of the candidate base station according to the
performances of all the neighbor cells belonging to the candidate base station
15 comprises:
calculating a sum of the performances or weighted performances of all the
neighbor cells belonging to the candidate base station based on the performance
measurement report, as the priority of the candidate base station.
20 10. An apparatus for cell handover, configured in a base station of a
communication system supporting carrier aggregation, and comprising:
a command forming device configured to judge, whether component carriers
corresponding to one or more cells to be accessed which belong to a destination base
station selected for a terminal device are in a same frequency band, wherein the
25 terminal device is currently served by the base station and is to be handed over, and
if yes, package configuration information of all the one or more cells to be accessed
in a handover command for initiating cell handover, otherwise, package
configuration information of one or more of the one or more cells to be accessed in
the handover command; and
30 a transmitting device configured to transmit the handover command to the
destination base station.
44
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
W Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
11. The apparatus for cell handover of claim 10, further comprising:
a primary cell selecting device configured to select one cell from the one or
more cells to be accessed, as a primary cell to be accessed.
5 12. The apparatus for cell handover of claim 11, wherein the primary cell
selecting device is configured to:
judge whether there is a cell, among the one or more cells to be accessed,
component carriers of which are in a same frequency band with those corresponding
to a currently serving cell of the terminal device; and if yes, select the cell as the
10 primary cell to be accessed, otherwise, select one cell having best performance
among the one or more cells to be accessed, as the primary cell to be accessed.
13. The apparatus for cell handover of claim 11, wherein the primary cell
selecting device is configured to:
15 select one cell having best performance among the one or more cells to be
accessed, as the primary cell to be accessed.
14. The apparatus for cell handover of claim 10, wherein if the terminal device
is currently connected to a plurality of cells of the base station, the terminal device
20 keeps in communication with one of the plurality of cells of the base station before
being handed over to the destination base station.
15. The apparatus for cell handover of claim 10, further comprising:
a receiving device configured to a performance measurement report for one or
25 more neighbor cells of the terminal device transmitted from the terminal device;
a destination base station selecting device configured to select, based on the
performance measurement report, a candidate base station from one or more
candidate base stations corresponding to the one or more neighbor cells, as the
destination base station; and
30 a cell selecting device configured to select one or more cells from all cells
belonging to the destination base station in the one or more neighbor cells, as the
45
Sony China Ref.: CNPA10034IN00
^ Sony Ref.: SP301383IN00
" Our Ref.: 0P1211-06-0477
EN Translation of PCX Spec
one or more cells to be assessed for the terminal device.
16. The apparatus for cell handover of claim 15, further comprising:
a priority determining device configured to select an algorithm suitable for
5 carrier aggregation manners of the one or more candidate base stations to calculate
priorities of the one or more candidate base stations, based on the performance
measurement report and based on the carrier aggregation manners of the one or
more candidate base stations; and
wherein the destination base station is configured to select one candidate base
10 station having a highest priority from the one or more candidate base stations, as
the destination base station.
17. The apparatus for cell handover of claim 16, wherein the priority
determining device is configured to calculate priorities of the one or more candidate
15 base stations by:
judging whether component carriers corresponding to all neighbor cells
belonging to a same candidate base station in the one or more neighbor cells are in a
same frequency band; and if yes, calculating priority of the candidate base station
according to performances of all the neighbor cells belonging to the candidate base
20 station, otherwise, calculating the priority of the candidate base station according to
performance one having best performance of all the neighbor cells belonging to the
candidate base station.
18. The apparatus for cell handover of claim 17, wherein the priority
25 determining device is configured to:
calculate a sum of the performances or weighted performances of all the
neighbor cells belonging to the candidate base station based on the performance
measurement report, as the priority of the candidate base station.
30 19. A base station in a communication system supporting carrier aggregation,
comprising the apparatus for cell handover of any one of claims 10-18.
46
Sony China Ref.: CNPA10034IN00
(tk Sony Ref^ SP301383IN00
Our Ref.: OP 1211 -06-0477
EN Translation of PCT Spec
20. A communication system supporting carrier aggregation, comprising the
base station of claim 19.