WO2014112848A1

WO2014112848A1 - Method and apparatus for transmitting and receiving capability information on user equipment in mobile communication system

Info

Publication number: WO2014112848A1
Application number: PCT/KR2014/000585
Authority: WO
Inventors: Soeng-Hun Kim; Gert Jan Van Lieshout; Jae-Hyuk Jang
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2013-01-21
Filing date: 2014-01-21
Publication date: 2014-07-24

Abstract

Disclosed are a method and an apparatus for transmitting and receiving capability information of a user equipment in a mobile communication system. The method of transmitting the capability information of the user equipment in the mobile communication system includes: generating the capability information including at least one supported bandwidth combination (SBWC) bitmap corresponding to at least one bandwidth class combination; and reporting the capability information to an evolved node B (ENB). In the method, the capability information includes at least one SBWC bitmap corresponding to each bandwidth class combination, and each bit of the SBWC bitmap indicates whether a certain bandwidth combination of a corresponding bandwidth class combination is supported.

Description

METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING CAPABILITY INFORMATION ON USER EQUIPMENT IN MOBILE COMMUNICATION SYSTEM

The present disclosure relates to a method and an apparatus for reporting capability of user equipment through a network in a mobile communication system.

Mobile communication systems have been developed for a purpose of providing communication while securing a mobility of a user. The mobile communication systems have reached a stage where a high speed data communication service can be provided as well as voice communication on the strength of the rapid development of technologies.

Currently, a standardization operation from a 3rd Generation Partnership Project (3GPP) system to a Long Term Evolution (LTE) system is being progressed as one of next generation mobile communication systems. The LTE system is a technology which implements high speed packet based communication having a transmission rate of a maximum of 100 Mbps, which is faster than a data transmission rate of the conventional 3GPP system. Various new technologies are applied to the recent LTE communication systems while keeping pace with the completion of the LTE standardization, and a discussion on a LTE-Advanced for significantly improving a transmission rate is regularized. Hereinafter, it must be understood that the LTE system refers to meaning in which it includes both the LTE system and a LTE-A system.

A representative one of new technologies employed to the LTE-A system is Carrier Aggregation (CA). The carrier aggregation is a technology in which user equipment transmits and receives data using multi-carriers. More particularly, the user equipment transmits and receives data through plural aggregated carriers (generally carriers belonging to an identical base station). In the end, this is identical to the user equipment transmitting and receiving the data through plural numbers of cells.

Technologies such as a Multiple Input Multiple Output (MIMO) and the like, as well as the carrier aggregation have been employed to the LTE-A system.

As described above, as the new technologies are introduced into the LTE-A system, a method is required in which capability information on the user equipment related to the technologies is efficiently reported to a base station, so that the base station and the user equipment efficiently perform mobile communication.

The present disclosure has been developed to solve the above-mentioned problem in the conventional art, and an aspect of the present disclosure is to provide a method and an apparatus for transmitting/receiving information in a communication system.

Another aspect of the present disclosure is to provide a method and an apparatus for reporting information on a technology such as carrier aggregation or MIMO from user equipment to a network in a mobile communication system.

Still another aspect of the present disclosure is to provide a method and an apparatus for minimizing an amount of reported information when user equipment reports capability information thereon.

Still another aspect of the present disclosure is to provide a method and an apparatus for improving efficiency in using a wireless transmission resource when a user equipment reports capability information thereon.

Still another aspect of the present disclosure is to provide a method and an apparatus for reporting information on a combination of bandwidth supported by user equipment to a network.

In accordance with an aspect of the present disclosure, a method of transmitting capability information of user equipment in a mobile communication system is provided. The method includes: generating capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and reporting the capability information to an Evolved Node B (ENB).

In accordance with another aspect of the present disclosure, a method of receiving capability information of User Equipment (UE) in a mobile communication system is provided. The method includes: receiving capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and controlling Carrier Aggregation (CA) for the UE based on the capability information.

In accordance with still another aspect of the present disclosure, user equipment (UE) for transmitting its capability information in a mobile communication system is provided. The UE includes: a controller generating the capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and a transmitter reporting the capability information to an Evolved Node B (ENB).

In accordance with still another aspect of the present disclosure, an evolved node B (ENB) apparatus for receiving capability information of user equipment in a mobile communication system is provided. The ENB apparatus includes: a receiver receiving the capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and a controller controlling Carrier Aggregation (CA) for the UE based on the capability information.

The capability information includes at least one SBWC bitmap corresponding to each bandwidth class combination, and each bit of the SBWC bitmap indicates whether a certain bandwidth combination of a corresponding bandwidth class combination is supported.

The above and other aspects, features, and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view illustrating a configuration of an LTE system to which the present disclosure is applied;

FIG. 2 is a view illustrating a configuration of a wireless protocol in the LTE system to which the present disclosure is applied;

FIG. 3 is a view illustrating carrier aggregation in user equipment;

FIG. 4 is a view illustrating a configuration of information on capability of user equipment according to an embodiment of the present disclosure;

FIG. 5 is a view illustrating a configuration of information on capability of user equipment according to another embodiment of the present disclosure;

FIG. 6 is a view illustrating a configuration of information on capability of user equipment according to still another embodiment of the present disclosure;

FIG. 7 is a view illustrating a configuration of information on capability of user equipment according to still another embodiment of the present disclosure;

FIGS. 8 and 9 are views illustrating a configuration of information on capability of user equipment according to still another embodiment of the present disclosure;

FIG. 10 is a view illustrating overall operations of the user equipment in the LTE system according to the embodiment of the present disclosure;

FIG. 11 is a flowchart illustrating operations of the user equipment according to the embodiment of the present disclosure;

FIG. 12 is a block diagram illustrating the user equipment according to the embodiment of the present disclosure; and

FIG. 13 is a block diagram illustrating Evolved Node B (ENB) equipment according to the embodiment of the present disclosure.

Hereinafter, a preferred embodiment of the present disclosure will be described with reference to the accompanying drawings. Further, in the following description of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear. Meanwhile, terms described later are defined in consideration of the functions of the present disclosure, but the meaning of the terms may be changed according to a user, intention of an operator, or convention. Therefore, its definition will be made based on the overall contents throughout this specification.

FIG. 1 is a view illustrating a configuration of an LTE system to which the present disclosure is applied. Herein, although an LTE system is illustrated as an example of a mobile communication system to which the present disclosure is applicable, of course, the present disclosure is not limited to the certain system.

Referring to FIG. 1, a wireless access network of the mobile communication system includes next generation evolved nodes B (hereinafter, referred to as an ENB, a Node B, or a base station) 105, 110, 115 and 120, a Mobility Management Entity (MME) 125, and a Serving-Gateway (S-GW) 130. A user equipment (hereinafter, referred to as a UE or a terminal) 135 accesses an external network (not shown) through the ENB 105, 110, 115 or 120 and the S-GW 130.

The ENB 105, 110, 115 or 120 corresponds to a conventional node B in a Universal Mobile Telecommunication System (UMTS). The ENB 105, 110, 15 or 120 is connected with the UE 135 through a wireless channel, and performs a more complicated role than the conventional node B. In the LTE system, all user traffic including a real time service such as a Voice over IP (VoIP) through an Internet Protocol (IP) are serviced through a shared channel. Therefore, an apparatus for collecting and scheduling information on a buffering state of the UE, a state of available transmission electric power, a channel state and the like is required. The ENB 105, 110, 115 or 120 is in charge of the apparatus. One ENB generally controls plural cells. Here, each cell corresponds to a component carrier.

In order to implement a transmission rate of 100 Mbps, the LTE system uses an Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology in a bandwidth of 20 MHz. Further, a modulation scheme and an Adaptive Modulation and Coding (hereinafter, referred to as an AMC) scheme of determining a channel coding rate are applied to the LTE system in correspondence to a channel status of the UE.

The S-GW 130 is a device for providing a data bearer, and generates or removes the data bearer under a control of a Mobility Management Entity (MME) 125. The MME 125 is a device for performing various control functions as well as a mobility management function for the UE, and is connected with a plurality of the

ENBs

105, 110, 115 and 120.

FIG. 2 is a view illustrating a configuration of a wireless protocol in the LTE system to which the present disclosure is applied.

Referring to FIG. 2, the UE and the ENB includes a Packet Data Convergence Protocol (PDCP) 205 or 240, a Radio Link Control (RLC) 210 or 235, a Medium Access Control (MAC) 215 or 230 respectively, as the wireless protocol of the LTE system. The PDCP 205 or 240 performs an operation of compressing and decompressing an IP header, and the RLC 210 or 235 reconstructs a PDCP Packet Data Unit or a PDCP Protocol Data Unit (PDCP PDU) in suitable size so as to perform an operation of an Automatic Retransmission Request (ARQ). The MAC 215 or 230 is connected with various RLC layer devices configured in one UE, and performs a multiplexing of RLC PDUs to MAC PDU and a demultiplexing of the RLC PDUs from the MAC PDU.

A

physical layer

220 or 225 performs a channel coding and a modulation of a higher layer data so as to make the higher layer data be an OFDM symbol, and then transmits the OFDM through a radio channel, or performs a channel decoding and a demodulation of an OFDM symbol received through the radio channel so as to transmit the decoded OFDM symbol to the higher layer, and performs an operation of a Hybrid ARQ (HARQ) for a transmission and a reception of data. In order to support a transmission of uplink data, the

physical layer

220 or 225 operates a Physical Uplink Shared Channel (PUSCH), a Physical HARQ Indicator Channel (PHICH) for transmitting an Acknowledgement (ACK)/Non-Acknowledgement (NACK) which is a HARQ feedback for a transmission of the PUSCH, a Physical Downlink Control Channel (PDCCH) for a transmission of a downlink control signal, e.g., scheduling information, and a Physical Uplink Control Channel (PUCCH) for a transmission of an uplink control signal. Further, the

physical layer

220 or 225 may operate the PDSCH in order to support a transmission of the downlink data.

FIG. 3 is a view illustrating carrier aggregation in the UE.

Referring to FIG. 3, one ENB generally transmits and receives multi-carriers through different frequency bandwidths. For example, when the ENB 305 transmits a carrier 315 in which a center frequency is f1, and a carrier 310 in which a center frequency is f3, a UE having no capability of aggregating carrier waves may transmit and receive data by using one of two

carriers

310 and 315. However, a UE 330 having capability of aggregating the carriers can simultaneously transmit and receive data to/from

different carriers

310 and 315. The ENB 305 may allocate many more carriers to the UE 330 with the carrier aggregation capability according to circumstances, so as to improve the transmission rate of the UE 330.

It may be understood that the carrier aggregation means that a UE simultaneously transmits and receives data through several cells when one downlink carrier and one uplink carrier which are transmitted and received by one ENB constitute one cell. A maximum data transmission rate increases in proportion to the number of carriers which are aggregated.

Hereinafter, in the following description of the embodiments of the present disclosure, the reception of the data through the downlink carrier or the transmission of the data through the uplink carrier in the UE has the same meaning as the transmission and reception of the data by using a control channel and a data channel which are provided by a cell corresponding to a center frequency and a frequency band which specify the carrier. In the description, 'carrier aggregation (CA)' is used to mean that a plurality of serving cells is set to one UE. Hereinafter, an LTE system will be described as an example of the present disclosure for convenience of the description, but the embodiments of the present disclosure may be applicable to all kinds of wireless communication systems supporting the carrier aggregation.

In order for the UE to properly operate in a given communication network, information (hereinafter, capability information) related to the capability of the UE should be provided to the network (or at least one specific network node). The capability information may include, for example, information on which feature and frequency the UE supports. As the capability of the UE is advanced and a new function such as a carrier aggregation is introduced, complexity and magnitude of the capability information of the UE also increases.

The capability information which the UE supporting the carrier aggregation has to report to the network includes as follows:

- a frequency band or frequency bands which the UE supports;

- a combination or combinations of frequency bands which the UE supports;

- a number of cells aggregated for each frequency band; and

- a maximum bandwidth of each frequency band.

The pieces of information are mutually combined with one another, so as to express meaningful capability. For example, the UE reports the following capability information to the network:

- aggregating two cells throughout a bandwidth of maximum 20 MHz as a downlink while aggregating two cells throughout a bandwidth of maximum 20 MHz as an uplink, in a band 1;

- aggregating two cells throughout a bandwidth of maximum 20 MHz as a downlink while aggregating one cell throughout a bandwidth of maximum 10 MHz as an uplink, in a band 1;

- aggregating two cells throughout a bandwidth of maximum 20 MHz as a downlink while aggregating one cell throughout a bandwidth of maximum 10 MHz as an uplink in the band 1, and aggregating two cells throughout a bandwidth of maximum 20 MHz while aggregating two cells throughout maximum 20 MHz as an uplink in a band 2; and the like.

The simplest method of reporting the capability information to the network is to clearly report the pieces of the information one by one. However, since it is a trend for the UE to support the an increasingly large number of band combinations due to the introduction of the new function such as carrier aggregation, the above-mentioned reporting method has a problem in that a magnitude of the capability information rapidly increases as the number of the band combinations increases. In order to efficiently and accurately report the capability of the UE, the capability information of the UE is preferably abbreviated and reported. To do this, a below proposal may be introduced.

First, a parameter named a Bandwidth Class (BWC) is used to express both a maximum aggregated bandwidth and a maximum number of cells. The BWC may be defined as an example in Table 1 below.

Table 1

CA Bandwidth Class	Aggregated Transmission Bandwidth Configuration	Maximum number of CCs (Component Carriers)
A	Aggregated bandwidth <= 20	1
B	Aggregated bandwidth <= 20	2
C	20 < Aggregated bandwidth <= 40	2
D	...	...
E	...	...
F	...	...

For example, a bandwidth class A for a certain band means that at most one component carrier (or one serving cell) may be set in the certain band and an aggregated bandwidth of the serving cell set in the band is maximum 20 MHz.

Second, when at least one bandwidth class is supported in a band of the band combination, information on the at least one bandwidth class is included in an identical information element (hereinafter, referred to as an IE). At this time, all combinations between the bandwidth classes received in one band combination constructs information on the band combination so that the UE supports the combinations.

FIG. 4 is a view illustrating a configuration of capability information of user equipment according to an embodiment of the present disclosure. Herein, particularly, an example of 'Supported Band Combination (hereinafter, referred to as an SBC)' IE included in the capability information of the UE is shown.

Referring to FIG. 4, the SBC IE 405 related to one band combination as an information element expressing the capability of the UE includes one or

more band parameters

410 and 427 indicating band information, and each

band parameter

410 or 427 includes at least one subordinate information element as described below:

- a

band indicator

415 or 428 is an index of indicating a band and has a value of 0 to 60, which is provided by 3GPP TS36.101.

- one or more

bandwidth class IEs

420 and 430 for a downlink.

- one or more

bandwidth class IEs

425 and 435 for an uplink.

In the case that one or more bandwidth classes are included in each band, several bandwidth class combinations per SBC are generated, and the UE must support all the bandwidth class combinations (a combination of the uplink and downlink bandwidth classes and a combination of the bandwidth classes of different bands). An example of SBC IE is indicated in Table 2 below.

Table 2

Supported Band Combination (SBC) IE
Band Parameter		Band Parameter
Band Indicator = 1		Band Indicator = 5
Bandwidth Class for Downlink	Bandwidth Class for Uplink	Bandwidth Class for Downlink	Bandwidth Class for Uplink
A	A	A	A
C	C	C

Information in Table 2 means that the UE supports band class combinations as in Table 3. That is, when all calculable combinations of the bands are obtained after all calculable combinations of a downlink and an uplink of the band 1 and all calculable combinations of a downlink and an uplink of the band 5 are firstly calculated, it is possible to obtain the combinations listed in below Table 3.

Table 3

	Downlink of Band 1	Uplink of Band 1	Downlink of Band 5	Uplink of Band 5
C0	A	A	A	A
C1	A	A	C	A
C2	C	A	A	A
C3	C	A	C	A
C4	A	C	A	A
C5	A	C	C	A
C6	C	C	A	A
C7	C	C	C	A

The certain combinations, e.g., the combinations C4 and C5 may have a greater number of uplink serving cells and a wider bandwidth than other combinations. An uplink heavier combination means a combination which has a greater number of the uplink serving cells than the number of downlink serving cells, or a wider aggregated uplink bandwidth than an aggregated downlink bandwidth. The uplink heavier combination generally may be not used and also may be not implemented in the UE. In many cases, it is impossible to constitute the SBC IE so that several numbers of bandwidth classes are included in the SBC IE while the uplink heavier combination is excluded from the SBC IE. Therefore, when the UE not supporting the uplink heavier combination constitutes the SBC IE for the certain combination, several SBC IEs satisfying a condition that the uplink heavier combination is excluded from the SBC IE must be constituted.

For example, two SBC IEs listed in Table 4 and Table 5 may be constituted for a combination of the band 1 and the band 5.

Table 4

Supported Band Combination (SBC) IE
Band Parameter		Band Parameter
Band Indicator = 1		Band Indicator = 5
Bandwidth Class for Downlink	Bandwidth Class for Uplink	Bandwidth Class for Downlink	Bandwidth Class for Uplink
A	A	A	A
C		C

Table 5

Supported Band Combination (SBC) IE
Band Parameter		Band Parameter
Band Indicator = 1		Band Indicator = 5
Bandwidth Class for Downlink	Bandwidth Class for Uplink	Bandwidth Class for Downlink	Bandwidth Class for Uplink
C	A	A	A
		C

It is advantageous in view of a signaling to generate a small number of the SBC IEs for the identical band combination. In the embodiment of the present disclosure described later, information indicating whether 'the uplink heavier combination' is supported is introduced instead of that several SBC IEs are generated so as to originally exclude the uplink heavier combination.

FIG. 5 is a view illustrating a configuration of information on capability of user equipment according to another embodiment of the present disclosure. Here, the 'Supported Band Combination (SBC)' IE included in the capability information of the UE is shown.

Referring to FIG. 5, the SBC IE 405 related to one band combination may further include optional IE referred to as 'uplink heavier combination supporting information' 507. If the information 507 is included in the SBC IE 405, this means that all the bandwidth class combinations of the SBC IE 405 are supported. On the other hand, if the information 507 is not included in the SBC IE 405, remaining bandwidth class combinations among the bandwidth class combinations of the SBC IE 405 from which the uplink heavier combination is excluded are supported.

A minimal unit of the bandwidth which the UE reports is 20 MHz. That is, all kinds of the UEs support the bandwidth of minimum 20 MHz, and are designed by a reference of a case that the bandwidth of a serving cell is 20 MHz. However, the bandwidth of the actual cell may be changed according to circumstances of a service provider, and in the provisions of the LTE, six bandwidths, e.g., 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz are provided as the bandwidth of the cell. In principle, if it is reported that the UE supports a certain bandwidth class combination, the ENB may determine that the serving cells of the six bandwidths can support each bandwidth class.

In view of an implementation of the UE, if the UE supports the desired bandwidth, it is possible to determine that the UE can also support the bandwidths lower than the desired bandwidth. However, in order for the UE and the ENB to operate properly in the mobile communication network, an Inter-Operability Test (IOT) is required. Items which do not pass the IOT are preferably not used. The six cell bandwidths to which requirements of the service provider are widely applied are implemented step by step according to a roadmap of the service provider. That is, since the cell having a certain bandwidth of the six bandwidths is not present surrounding the UE, there may be a case in which it is impossible for the UE to perform the IOT along with the cell with the certain bandwidth. Therefore, a signaling indicating which bandwidth the UE performs the IOT along with the cells is required for each SBC.

For example, it is necessary to indicate which cell bandwidth in each bandwidth class is supported for each bandwidth class combination. In other words, it is necessary to indicate which cell bandwidth combination is supported for each bandwidth class combination. The simplest method is to individually indicate the information for each combination. For example, for C0 (a combination of the band 1 and the band 5; a bandwidth class is all A) in Table 3, the UE may additionally report information in below Table 6 to the ENB.

Table 6

Uplink/Downlink	E-UTRA Bands	1.4 MHz	3 MHz	5 MHz	10 MHz	15 MHz	20 MHz
Downlink	1				Yes
Uplink	1				Yes
Downlink	5				Yes		Yes
Uplink	5				Yes		Yes

The information in Table 6 means that the UE supports all combinations of the bandwidths which are indicated by Yes (a combination of the uplink and downlink for each band, and a combination of the bands with the combinations of the uplink and downlink. That is, combinations in below Table 7 are supported.

Table 7

	Downlink of Band 1	Downlink of Band 5	Uplink of Band 1	Uplink of Band 5
C0	10 MHz	10 MHz	10 MHz	10 MHz
C1	10 MHz	20 MHz	10 MHz	10 MHz
C2	10 MHz	10 MHz	10 MHz	20 MHz
C3	10 MHz	20 MHz	10 MHz	20 MHz

One serving cell generally has an uplink and a downlink which have an identical bandwidth, and in a certain system, the bandwidth of the uplink and downlink of one cell may be not used in other cells. Two combinations remain if combinations C1 and C2 having different uplink/downlink bandwidths are excluded from the combinations. Accordingly, it is possible to express through the information in Table 6 that the UE supports combinations in Table 8.

Table 8

	Downlink of Band 1	Downlink of Band 5	Uplink of Band 1	Uplink of Band 5
C0	10 MHz	10 MHz	10 MHz	10 MHz
C3	10 MHz	20 MHz	10 MHz	20 MHz

Additionally, a signaling system can be simplified by separating information on the uplink from information on the downlink. Further, if combinations supported by the downlink and uplink are identical, a signaling overhead may be further reduced by signaling one of them.

An expression of contents in Table 6 in a text is simple. However, in order to express the contents in a computer language such as an Abstract Syntax Notation One (ASN 1) code, a significantly complicated rule and various information elements must be introduced. To avoid this, the information in Table 6 is defined in the rule and only information indicating which combination 'Supported Bandwidth Combination (hereinafter, referred to as a SBWC)' of the UE is may be transmitted in the form of a signaling. As an example, the rule defines Table 9 below, and the UE indexes the bandwidth combinations for each bandwidth class combination according to Table 9 and then reports only information on the index.

Table 9

	E-UTRA Bands	1.4 MHz	3 MHz	5 MHz	10 MHz	15 MHz	20 MHz	Index
1A-5A	1				Yes			0
	5				Yes			0
	1				Yes		Yes	1
	5				Yes		Yes	1
	1			Yes	Yes		Yes	2
	5				Yes		Yes	2

As a selectable embodiment, a bitmap (bandwidth combination bitmap) is defined and each bit of the bitmap may be related to the index. The bitmap (hereinafter, referred to as a SBWC bitmap) is preferably defined by each link, each band combination and each bandwidth class combination. For example, Table 9 is an index of the 'SBWCs' corresponding to a case that a band class of the band 1 for the uplink or the downlink is A and a band class of the band 5 is A. Hereinafter, in the written "integral number letter ?? integral number letter", the integral number indicates a band to be combined, and the letter denotes a band class to be combined.

Therefore, the SBWC bitmap is generated and transmitted for each band combination, each link, and each bandwidth class combination. Since one or more downlink bandwidth class combinations may be included in one piece of SBC IE, one SBC is associated with several SBWC bitmaps. Accordingly, the UE generates and transmits several SBWC bitmaps for each SBC. The bandwidth class combinations and the SBWC bitmaps which are derived from the SBC must be mutually mapped. At this time, the UE and the ENB share an identical mapping rule.

In the embodiment of the present disclosure, a sequence of the bandwidth class combinations is impliedly determined in correspondence to a sequence of letters of the bandwidth class combinations, and the SBWC bitmaps are arranged by a reference of the sequence. The sequence of the letters may increase in proportion to the number of the cells and the aggregated bandwidths. Therefore, the sequence of the bandwidth class combinations is determined according to the sequence of the aggregated bandwidths, and by a reference of the number of the cells in the identical bandwidth class.

For example, if four bandwidth class combinations 1A-5A, 1A-5C, 1C-5A and 1C-5C are generated for a certain SBC, four downlink SBWC bitmaps and four uplink SBWC bitmaps for the SBC are reported, a first bitmap relates to the 1A-5A with a first letter, a second bitmap relates to 1A-5C, a third bitmap relates to 1C-5A, and a final bitmap relates to 1C-5C. Four uplink bandwidth combination bitmaps also are reported in identical sequence.

FIG. 6 is a view illustrating a configuration of information on capability of user equipment according to still another embodiment of the present disclosure. Here, the 'Supported Band Combination (SBC)' IE included in the capability information of the UE is shown.

Referring to FIG. 6, one piece of SBC IE 405 includes one or more SBWC bitmaps 640 and 645 for the downlink and one or more bitmaps SBWC bitmaps 650 and 655 for the uplink.

The

bitmaps

650 and 655 for the uplink is a selective information element, and may be not signaled if they are identical to the bandwidth combination bitmap for the downlink, or are a sub-set of information indicated in the bandwidth combination bitmap for the downlink. For example, if 1A-5A and 1A-5C are present as the downlink band class combinations and only 1A-5A is present as the uplink band class combination (i.e., the uplink band class combination is a subset of the downlink band class combination), and the SBWC bitmap for 1A-5A of the downlink and the SBWC bitmap for 1A-5A of the uplink are identical, the SBWC bitmap for the uplink is not signaled.

If several band class combinations are present in the downlink, there is high possibility in that the UE supports all indexes with respect to a combination of a low band class, while there is low possibility in that the UE supports all indexes for a combination of a high band class. If n band class combinations are derived from a certain band combination, in which a part of the SBWC is supported for the highest band class combination and all the SBWCs are supported for the remaining band class combinations (i.e., all the SBWCs are able to be supported in the bitmap), the UE may make only the SBWC bitmap for the highest band class combination to be included in the downlink while omitting the SBWC bitmap for the remaining band class combination.

That is, if only one SBWC bitmap is included in the SBC IE from which n downlink band class combinations and m downlink band class combinations are derived, the SBC IE has meanings as described below:

- Uplink band class combinations of the SBC IE are identical to downlink band class combinations or a subset;

- a support of the SBWC for a certain uplink band class combination is identical to a support of the SBWC for an identical downlink band class combination;

- all the SBWCs for corresponding combinations are supported to the remaining band class combinations except for the highest downlink band class combination (in the case that there are several band class combinations with the highest aggregated bandwidth, the band class combination with the highest number of aggregated serving cells among the band class combinations); and

- the SBWC bitmap is information indicating the support of the SBWC for the highest band class combination.

In a word, if the SBWC bitmap for the uplink is not included in the SBC IE, the SBWC bitmaps 640 and 645 for the downlink are substantially information on both the uplink and the downlink. That is, if the SBWC bitmap for the uplink is present, the SBWC bitmap for the downlink is applied to only the downlink, while if the SBWC bitmap for the uplink is not present, the SBWC bitmap for the downlink is information commonly applied to the uplink and the downlink.

If only one SBWC bitmap is included in the SBC IE from which n downlink band class combinations and m downlink band class combinations are derived, the SBC IE may have meanings as described below:

- a support of the SBWC for a certain uplink band class combination is identical to a support of the SBWC for an identical downlink band class combination; and

- the SBWC bitmap is information indicating the common support of the SBWC for the highest band class combination. Bits of the SBWC bitmap are information commonly applied to all derived band class combinations. If a certain bit is not defined for a certain band class combination, the certain bit is applied to only a band class combination for which the bit is defined.

For example, when two band class combinations 1A-5A and 1A-5C are derived from one SBC, each bit may be defined as in below Tables 10 and 11.

Table 10

Table 11

	E-UTRA Bands	1.4 MHz	3 MHz	5 MHz	10 MHz	15 MHz	20 MHz	Index
1A-5C	1				Yes			0
	5				Yes			0
	1				Yes		Yes	1
	5				Yes		Yes	1

A first bit of the SBWC bitmap commonly expresses a support for an index 0 of 1A-5A and an index 0 of 1A-5C (i.e., if the first bit is 0, the two indexes are not supported, while if the first bit is 1, the two indexed are supported), and a third bit expresses only a support for an index 2.

In the configuration of the SBWC, according to another embodiment of the present disclosure, each UE reports only one bitmap for each of the downlink and the uplink, in which the bitmap generally indicates all bandwidth class combinations which the UE supports. In this case, a total magnitude of the bitmaps increases, but the number of the bitmaps is remarkably reduced. In even case where a bitmap for each bandwidth class combination is used, the magnitude of each bitmap may be set to a value larger than a desired value in preparation for an introduction of a new index in the future. Accordingly, a significant portion of the bitmap reported by a reference of each bandwidth class combination carries meaningless information (index not defined yet).

For example, although three indexes are defined for the bandwidth class combination 1A-5A as indicated in Table 9, each bitmap must be defined, for example, as 16 bits or 32 bits so as to carry much more information. Therefore, instead of signaling one bitmap for each bandwidth class combination, it is advantageous in view of an overhead that the bitmaps are aggregately configured and then one set of bitmaps is signaled for each link.

For example, the UE and the ENB store a common list in advance, which is indicated in Table 12, and the UE reports the SBWC by using the index in the common list.

Table 12

	E-UTRA Bands	1.4 MHz	3 MHz	5 MHz	10 MHz	15 MHz	20 MHz	Index
1A-2A	1				Yes			0
	2				Yes			0
	1				Yes		Yes	1
	2				Yes		Yes	1
	1			Yes	Yes		Yes	2
	2				Yes		Yes	2
1A-3A	1				Yes			3
	3				Yes			3
	1				Yes			4
	3		Yes					4
	1						Yes	5
	3		Yes					5
2A-3A	2				Yes	Yes		6
	3	Yes	Yes					6
	2				Yes		Yes	7
	3		Yes					7
	2			Yes	Yes			8
	3		Yes					8
1A-2C	...							9
	...							10
	...							11
	...							12
	...							13
...	...							..

In the 'common list for a single SBWC bitmap' of Table 12, all bandwidth combinations which are able to be tested and implemented at a corresponding time point are included and indexed. The indexing operation may be performed under mutual conference of an association in which all service providers/vendors participate, and a corresponding item is added to the list each time when a new bandwidth combination is introduced.

In brief, when the UE reports its capability, it reports one or more pieces of SBC IE based on a band combination which it supports. Further, the UE reports the SBWC bitmap indicating whether the SBWC is supported for each of the bandwidth class combinations derived from the pieces of the SBC IE. The SBWC bitmap may be reported one by one for the downlink and the uplink. If a below condition is satisfied, only one SBWC bitmap is reported and the SBWC bitmap is applied to all the uplink and the downlink.

FIG. 7 is a view illustrating a configuration of information on capability of user equipment according to still another embodiment of the present disclosure. Here, the SBC IE included in the capability information of the UE is shown.

A case where the UE supports band combinations 1-2, 1-3 and 2-3 will be described with reference to FIG. 7. The UE generates and includes pieces of

SBC IE

705, 710 and 715 which correspond to the combinations respectively, in a message for reporting the capability thereof, and transmits the pieces of the SBC IE to an ENB. For the SBC IE 705 of the band combination 1-2, two downlink bandwidth class combinations 1A-2A and 1A-2C are derived. For the SBC IE 710 of the band combination 1-3, the downlink bandwidth class combination 1A-3A is derived. For the SBC IE 715 of the band combination 2-3, the downlink bandwidth class combination 2A-3A is derived. Then, the UE generates one bandwidth combination bitmap 720, in which bits which correspond to bandwidth combinations which it supports, among the bits corresponding to the bandwidth combinations of the bandwidth class combinations which it supports, are set to one (1) and the remaining bits are set to zero (0), and includes the bandwidth combination bitmap 720 in the capability reporting message.

That is, the UE indicates whether each SBWC is supported for the SBWCs of 1A-2A by using the bits corresponding to indexes 0, 1 and 2, denotes whether each SBWC is supported for the SBWCs of 1A-3A by using the bits corresponding to indexes 3, 4 and 5, indicates whether each SBWC is supported for the SBWCs of 2A-3A by using the bits corresponding to 6, 7 and 8, and denotes whether each SBWC is supported for the SBWCs of 1A-2C by using the bits corresponding to 9, 10, 11, 12 and 13.

Meanwhile, the bitmap 725 may be selectively included in the capability reporting message with respect to the uplink bandwidth class combinations. If the reported information for the uplink is identical to the information of the downlink, or is a subset of the information of the downlink, the bitmap 725 for the uplink is excluded from the capability reporting message. In this case, the bitmap 720 for the downlink is substantially and commonly applied to the uplink and the downlink.

For example, a total of three band class combinations 1A-2A, 1A-3A and 2A-3A are derived for the uplink. If a condition of supporting the SBWC of the band class combination is identical to a supporting condition in the downlink, in other words, a bit for indexes 0, 1, 2, 3, 4, 5, 6, 7 and 8 in the uplink SBWC bitmap is identical to a bit for the identical indexes in the downlink SBWC bitmap, the UE does not include the SBWC bitmap 725 for the uplink in the capability reporting message.

If the capability reporting message includes only one SBWC bitmap and a SBWC corresponding to an index n is effective for the downlink, a bit for the index n of the bitmap indicates whether the SBWC is supported in the downlink. That is, if the bit is zero (0), this means that the SBWC of the index n is not supported for the downlink, and if the bit is one (1), this means that the SBWC of the index n is supported for the downlink.

If the capability reporting message includes only one SBWC bitmap and a SBWC corresponding to an index n is effective for both the downlink and the uplink, a bit for the index n of the bitmap aggregately indicates whether the downlink SBWC and the uplink SBWC are supported. That is, if the bit is zero (0), this means that the SBWC of the index n is not supported for both the downlink and the uplink, and if the bit is one (1), this means that the SBWC of the index n is not supported for both the downlink and the uplink.

As still another embodiment, the UE and the ENB may store an effective list for each band combination in advance. For example, the UE and the ENB shares a common list as indicated in Table 13 in advance, and the UE reports a SBWC for each SBC to the ENB by using an index in a below common list.

Table 13

	E-UTRA Bands	1.4 MHz	3 MHz	5 MHz	10 MHz	15 MHz	20 MHz	Index
1A-2A	1				Yes			0
	2				Yes			0
	1				Yes		Yes	1
	2				Yes		Yes	1
	1			Yes	Yes		Yes	2
	2				Yes		Yes	2
1A-2C	1				Yes			3
	2				Yes			3
	1				Yes			4
	2		Yes					4
	1						Yes	5
	2		Yes					5
2A-3A	2				Yes	Yes		0
	3	Yes	Yes					0
	2				Yes		Yes	1
	3		Yes					1
	2			Yes	Yes			2
	3		Yes					2
2A-3C	...							3
	...							4
	...							5
	...							6
	...							7
...	...							..

In the common list, the index is consistently allocated to each band combination. For example, with relation to SBWCs belonging to each band combination 1A-2A or 1A-2C which is a combination of the band 1 and the band 2, the index is allocated so that an identical identifier is not allocated to one or more SBWCs. In the example, the indexes 0, 1 and 2 are allocated to the band combination 1A-2A, and the indexes 3, 4 and 5 are allocated to the band combination 1A-2C. For the band combination and another band combination, for example, a band 2 and a band 3, the indexes are independently allocated. The indexes 0, 1 and 2 are reused to the band combination 2A-3A, and the indexes 3, 4 and 7 are reused to the band combination 2A-3C.

Accordingly, the SBWC bitmap is signaled one by one for each band combination, and a SBWC related to each bit is changed according to which SBC the bitmap is signaled for. Several SBCs may be signaled for the identical band combination. In this case, since the UE may include a SBWC bitmap in only one SBC among them, information on a support of SBWC of another SBC of the identical band combination is included in the SBWC bitmap.

FIG. 8 is a view illustrating a configuration of capability information of user equipment according to still another embodiment of the present disclosure. In FIG. 8, a case where the UE supports the band combinations 1-2 and 2-3 is shown as an example.

Referring to FIG. 8, the UE supports the downlink bandwidth class combinations 1A-2A, 1A-2C and 2A-3A, and the uplink bandwidth class combinations 1A-2A and 2A-3A. For example, the UE generates

plural SBC IEs

805 and 810 on the band combination 1-2 if measurement gap requirements for the down link bandwidth class combinations 1A-2A and 1A-2C are different. The SBC IE 805 includes information on the bandwidth class combination 1A-2A, and the SBC IE 810 includes information on the bandwidth class combination 1A-2C. The UE selects one of the plural SBC IEs for the identical band combination, and includes a SBWC bitmap for the corresponding band combination in the identical band combination. For example, the SBWC bitmap is included in the SBC IE 810, in which a first bit is related to an index 0 of the band combination 1-2 in the common list indicated in Table 13, and nth bit is associated with an index n-1 of the band combination 1-2.

The SBWC bitmap is included in the SBC IE 815 for the band combination 2-3, in which a first bit of the is related to an index 0 of the band combination 2-3 in the common list indicated in Table 13, and nth bit is associated with an index n-1 of the band combination 2-3.

FIG. 9 is a view illustrating a configuration of capability information of the user equipment according to still another embodiment of the present disclosure. In the shown embodiment, the SBWC bitmaps 920, 925 and 930 are included in the capability information of the UE as not subordinates of the

SBC IEs

905, 910 and 915 but separate IEs. Each SBWC bitmap is specified which SBC IE it is associated with by a reference of sequence of the SBWC bitmaps and the SBCs.

Referring to FIG. 9, when three

SBC IEs

905, 910, and 915 are received in the capability information of the UE, a first SBWC bitmap 920 is associated with a band combination of a first SBC IE 905, and a second SBWC bitmap 925 is related to a band combination of a second SBC IE 910. If the SBWC bitmap for the identical band combination is included in the capability information of the UE, the SBWC bitmap may be omitted. A third SBC bitmap 930 is associated with a band combination of a third SBC IE 915.

FIG. 10 is a flowchart illustrating overall operations of the user equipment in the LTE system according to the embodiment of the present disclosure.

Referring to FIG. 10, a UE is powered on in a mobile communication system including a UE 1005, an ENB 1010, and an MME 105 in step 1020. The UE 1005 detects a cell receiving a radio wave and a Public Land Mobile Network (PLMN) indicating a communication service provider through a cell search procedure, and determines which cell of the PLMN a registration procedure is performed through, based on the detected cell and PLMN in step 1025.

The UE 1005 performs a process of connecting and setting a Radio Resource Control (RRC) through the selected cell, and then transmits an ATTACH REQEST message for requesting a registration to the MME 1015 in step 1030. The ATTACH REQUEST message includes information such as an identifier of the UE 1015.

The MME 1015 determines whether it receives the ATTACH REQUEST message and permits the registration of the UE 1015, and then transmits an Initial Context Setup Request message, which is a control message for an initial setup, to a serving ENB 1010, if it is determined that the registration of the UE is permitted, in step 1035. If the MME 1015 has the capability information of the UE 1005, the message includes the capability information of the UE. However, in the initial registration process, the message does not include the capability information of the UE 1005 because the MME 1015 also does not have this information.

The ENB 1010 receives the Initial Context Setup Request message without the capability information of the UE 1005, and transmits a control message named UE CAPABILITY ENQUIRY to the UE 1005 in step 1040. The message instructs the UE 1005 to report its capability, which includes a parameter named a Radio Access Technology (RAT) Type requiring capability information for a certain RAT of the UE. For example, if the UE 1005 is connected to an LTE network, the RAT-Type is set to an Evolved Universal Terrestrial Radio Access (EUTRA). The ENB 1010 also may add an UTRA to the RAT-Type and require capability information related to UMTS of the UE in preparation for a handover if another wireless network, e.g., an UMTS network, is present around the ENB 1010.

The UE 1005 generates a UE CAPABILITY INFORMATION message which is a control message of receiving the capability information thereof for the RAT instructed by the RAT Type as receiving a UE CAPABILITY ENQUIRY control message. The message receives one or more SBC IEs for each band combination which the UE supports, according to one of the embodiments described above, and also receives one or two SBWC bitmaps. The SBC IE is constituted of one or more band parameters, and may selectively include uplink heavier combination supporting information. A SBWC bitmap for a downlink and a SBWC bitmap for an uplink are individually received in the capability control message, or one SBWC bitmap commonly applied to two links may be received in the capability control message. As another example, one SBWC bitmap of each band class combination for each link may be received in the capability control message.

Although it is not shown, the UE 1005 may generate the UE CAPABILITY INFORMATION message which is the control message of receiving its capability information according to a predetermined reference (period or triggering event) without receiving the control message of the UE CAPABILITY ENQUIRY.

The UE 1005 transmits the UE CAPABILITY INFORMATION message to the ENB 1010 in step 1045. The ENB 1010 transmits the UE CAPABILITY INFORMATION message to the MME 1015 in order to report the capability information of the UE 1005 received in the UE CAPABILITY INFORMATION message, to the MME 1015 in step 1050. The ENB 1010 also sets the UE 1005 again with reference to a traffic condition or a channel condition of the UE 1005, based on the capability information which the UE 1005 reports. For example, the ENB 1010 may set an additional serving cell to the UE 1005. At this time, the ENB 1010 determines which serving cell of a bandwidth the UE 1005 sets for each band combination and each band which the UE 1005 supports considering the SBC IE and the SBWC bitmap(s) which the UE 1005 reports, and decides the serving cell to be set, in step 1055. The UE 1005 performs a reset of the serving cell according to an instruction of the ENB 1010 in step 1060, and performs communication through at least one set serving cell.

FIG. 11 is a flowchart illustrating operations of the user equipment according to the embodiment of the present disclosure.

Referring to FIG. 11, in step 1105, when receiving the UE CAPABILITY ENQUIRY message, the UE performs step 1110 and identifies the RAT Type included in the message. Alternatively, the UE determines to report the capability information according to a predetermined condition, and may perform step 1110.

If the RAT Type is set to EUTRA, the UE performs step 1120, while if the RAT Type is set to not the EUTRA but another value, the UE performs step 115. In step 1115, the UE operates according to the conventional technology. In step 1120, the UE contains its capability information generated according to at least one of the above described embodiments in the UE CAPABILITY INFORMATION, and transmits the UE CAPABILITY INFORMATION message to the ENB. The capability information includes the SBWC bitmap and the SBC IE which are coded by ASN.1 according to at least one of the above-mentioned embodiments.

FIG. 12 is a block diagram illustrating the configuration of the user equipment according to an embodiment of the present disclosure.

Referring to FIG. 12, the UE includes a signal transmitting and receiving unit (that is a transceiver) 1205, a controller 1210, a multiplexing and demultiplexing unit (MUX/DEMUX) 1215, a control message processor 1230, and one or more

higher layer processors

1220 and 1225.

The transmission and reception unit 1205 receives data and a predetermined control signal through a forward channel of a serving cell, and transmits data and a predetermined control signal through a backward channel. In the case that a plurality of serving cells is set, the signal transmitting and receiving unit 1205 transmits and receives data and a control signal through the plurality of serving cells.

The multiplexing and demultiplexing unit 1215 multiplexes data generated by the

higher layer processors

1220 and 1225 or the control message processor 1230, or demultiplexes data received in the signal transmitting and receiving unit 1205 to transmit the data to the suitable

higher layer processors

1220 and 1225 or the control message processor 1230.

The control message processor 1230 processes the control message received from the ENB, and performs a necessary operation. Particularly, when receiving a control message such as the UE CAPABILITY ENQUIRY, the control message processor 1230 analyzes contents of the control message and performs a necessary operation, for example, generates and transmits a UE CAPABILITY INFORMATION control message including the capability information of the UE to the

subordinate layers

1015 and 1005. The UE CAPABILITY INFORMATION control message includes the SBC IE and the SBWC bitmap which are coded according to at least one of the above-described embodiments.

The

higher layer processors

1220 and 1225 may be configured according to each service, which processes and transmits data generated by a user service such as File Transfer Protocol (FTP) or Voice over Internet Protocol (VoIP) to the multiplexing and demultiplexing unit 1215 or processes and transmits data received from the multiplexing and demultiplexing unit 1215 to a higher layer service application.

The controller 1210 identifies a scheduling instruction received through the signal transmitting and receiving unit 1205, for example, backward grants, and controls the signal transmitting and receiving unit 1205 and the multiplexing and demultiplexing unit 1215 so as to perform a backward transmission through a suitable transmission resource at an appropriate time point.

FIG. 13 is a block diagram illustrating the configuration of the ENB according to the embodiment of the present disclosure, in which the ENB includes a signal transmitting and receiving unit (that is a transceiver) 1305, a controller 1310, a multiplexing and demultiplexing unit (MUX/DEMUX) 1320, a control message processor 1335,

higher layer processors

1325 and 1330, and a scheduler 1315.

Referring to FIG. 13, the signal transmitting and receiving unit 1305 transmits data and a desired control signal carried with a forward carrier, and receives data and a desired control signal carried with a backward carrier. In the case that a plurality of carriers is set, the signal transmitting and receiving unit 1305 transmits and receives data and a control signal carried with the plurality of carrieres.

The multiplexing and demultiplexing unit 1320 multiplexes data generated by the

higher layer processors

1325 and 1330 or the control message processor 1335, or demultiplexes data received in the signal transmitting and receiving unit 1305 to transmit the data to the suitable

higher layer processors

1325 and 1330, the control message processor 1335, or the controller 1310. The control message processor 1335 processes a control message received from the UE to transmit necessary information to the controller, or generates and transmits a control message transmitted to the UE to the subordinate layer under a control of the controller.

The

higher layer processors

1325 and 1330 may be constituted for each bearer, which constitutes the RLC PDU of data received from the S-GW or another ENB to transmits the RLC PDU to the multiplexing and demultiplexing unit 1320, or constitutes the PDCP SDU of the RLC PDU received from the multiplexing and demultiplexing unit 1320 to transmit the PDCP SDU to the S-GW or another ENB.

The scheduler 1315 allocates a transmission resource to the UE at a suitable time point considering a buffer state, a channel state, and the like of the UE, and enables the signal transmitting and receiving unit 1305 to process a signal received from the UE, or to transmit a signal to the UE.

The controller 1310 instructs the control message processor 1335 to generate and transmit a suitable RRC control message to the UE, or performs necessary operations by using control information processed by the control message processor 1335. For example, the controller 1310 determines which serving cell and which frequency band are added to the UE considering the SBC IE and the SBWC bitmap in the capability information message received from the UE. That is, the controller performs an operation corresponding to an operation of the UE shown in FIGS. 10 and 11, and a necessary control operation.

Although specific exemplary embodiments have been described in the detailed description of the present disclosure, various modifications may be made without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be defined as being limited to the embodiments, but should be defined by the appended claims and equivalents thereof.

Claims

A method of transmitting capability information of user equipment in a mobile communication system, the method comprising:

generating capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and

reporting the capability information to an Evolved Node B (ENB),

wherein the capability information includes at least one SBWC bitmap corresponding to each bandwidth class combination, and each bit of the SBWC bitmap indicates whether a certain bandwidth combination of a corresponding bandwidth class combination is supported.
The method as claimed in claim 1, wherein each bandwidth class combination is a combination of bands in which one or more serving cells are set, and is expressed by combinations of letters which indicate number of the serving cells to be set in a corresponding band, and a maximum aggregated bandwidth of the serving cells.
The method as claimed in claim 1, wherein each bit of the SBWC bitmap is mapped with one of indexes indicating a plurality of bandwidth combinations supported by a corresponding bandwidth class combination.
The method as claimed in claim 1, further comprising: storing a table for mapping indexes which indicate a plurality bandwidth combinations supported by each of bandwidth class combinations, with a plurality of bandwidth class combinations.
The method as claimed in claim 4, wherein the indexes are allocated in sequence to each bandwidth class combination, and are independently allocated from zero (0) to different bandwidth class combinations.
A method of receiving capability information of User Equipment (UE) in a mobile communication system, the method comprising:

receiving capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and

controlling Carrier Aggregation (CA) for the UE based on the capability information,

wherein the capability information includes at least one SBWC bitmap corresponding to each bandwidth class combination, and each bit of the SBWC bitmap indicates whether a certain bandwidth combination of a corresponding bandwidth class combination is supported.
The method as claimed in claim 6, wherein each bandwidth class combination is a combination of bands in which one or more serving cells are set, and is expressed by combinations of letters which indicate an integer indicating a band, a number of the serving cells to be set in a corresponding band, and a maximum aggregated bandwidth of the serving cells.
The method as claimed in claim 6, wherein each bit of the SBWC bitmap is mapped with one of indexes indicating a plurality of bandwidth combinations supported by a corresponding bandwidth class combination.
The method as claimed in claim 6, further comprising: storing a table for mapping indexes which indicate a plural bandwidth combinations supported by each of bandwidth class combinations, with a plurality of bandwidth class combinations.
The method as claimed in claim 9, wherein the indexes are allocated in sequence to each bandwidth class combination, and are independently allocated from zero (0) to different bandwidth class combinations.
A user equipment (UE) for transmitting its capability information in a mobile communication system, the UE comprising:

a controller generating the capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and

a transmitter reporting the capability information to an Evolved Node B (ENB),

wherein the capability information includes at least one SBWC bitmap corresponding to each bandwidth class combination, and each bit of the SBWC bitmap indicates whether a certain bandwidth combination of a corresponding bandwidth class combination is supported.
The user equipment as claimed in claim 11, wherein the UE is configured to perform a method according to one of claims 1, 2, 3, 4 and 5.
An evolved node B (ENB) apparatus for receiving capability information of a user equipment in a mobile communication system, the ENB apparatus comprising:

a receiver receiving the capability information which includes at least one Supported Bandwidth Combination (SBWC) bitmap corresponding to at least one bandwidth class combination including a band and a bandwidth class; and

a controller controlling Carrier Aggregation (CA) for the UE based on the capability information,

wherein the capability information includes at least one SBWC bitmap corresponding to each bandwidth class combination, and each bit of the SBWC bitmap indicates whether a certain bandwidth combination of a corresponding bandwidth class combination is supported.
The ENB apparatus as claimed in claim 13, wherein the ENB apparatus is configured to perform a method according to one of claims 6, 7, 8, 9 and 10.