Abstract:
A base station (BS) which communicates with a plurality of mobile stations (MSs) is configured so as to comprise a control signal generation unit which generates control signals showing information on the allocation of resources for each of the plurality of mobile stations (MSs), and a transmission unit which transmits the control signals to the plurality of mobile stations (MSs). A control signal for a given mobile station (MS) includes information relating to another mobile station (MS).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. patent application Ser. No. 13/638,729, filed on Oct. 1, 2012, entitled “BASE STATION, MOBILE STATION, COORDINATED MOBILE STATION, TRANSMISSION METHOD AND RECEPTION METHOD”, which claims priority to PCT/JP2011/002313, filed Apr. 20, 2011, the entireties of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a base station, a mobile station, a cooperating mobile station, a transmission method and a reception method that perform client collaboration. 
       BACKGROUND ART 
       [0003]    The IEEE (Institute of Electrical and Electronics Engineers) 802.16 Working Group is developing the 802.16m air interface specification to meet the requirements of IMT (International Mobile Telecommunications)—Advanced next generation mobile systems. Based on the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), the WiMAX (Worldwide Interoperability for Microwave Access) Forum is working out the WiMAX Release 2.0 MSP (Mobile System Profile) and PICS (Protocol Implementation Conformance Statement). The IEEE 802.16m standard and the WiMAX Release 2.0 MSP and PICS are expected to be finalized in early 2011. 
         [0004]    The IEEE 802.16 Working Group has also started envisioning the future 802.16/WiMAX networks beyond 802.16m/WiMAX 2.0. There is a common understanding among 802.16/WiMAX community that future 802.16/WiMAX networks should support explosive mobile data traffic growth driven by large screen devices, multimedia applications as well as more connected users and devices. Future 802.16/WiMAX networks should also interwork efficiently with other radio technologies, e.g., 802.11/Wi-Fi (Wireless Fidelity). 
         [0005]    Future 802.16/WiMAX networks should be enhanced significantly compared with 802.16m network in terms of various performance metrics such as throughput and SE (Spectral Efficiency). For example, in urban-coverage scenario, future 802.16/WiMAX networks target at the cell-edge SE of two times of 802.16m/WiMAX 2.0 network in both UL (Uplink) and DL (Downlink) (e.g., see Non-Patent Literature 2). Note that 802.16m/WiMAX 2.0 network has at least a DL cell-edge SE of 0.06 bps/Hz/sec with 4×2 antenna configuration and an UL cell-edge SE of 0.03 bps/Hz/sec with 2×4 antenna configuration. 
         [0006]    Co-operative techniques, e.g., CliCo (Client Collaboration), have promised significant improvements in the cell-edge SE and total network energy efficiency of a wireless communication system. CliCo is a technique where clients interact to jointly transmit/receive data in wireless environments (e.g., see Non-Patent Literature 3). In CliCo, client clustering and peer-to-peer communication are exploited to transmit/receive information over multiple paths between BS and client. As a result, the cell-edge SE can be improved without increase in infrastructure cost. Furthermore, the battery of clients with poor channels can be extended. 
         [0007]    A diagram illustrating an exemplary wireless communication system  100  with CliCo is shown in  FIG. 1 . Wireless communication system  100  is configured of BS (Base Station)  102  and a plurality of MSs (Mobile Stations) such as MS  104  and MS  106 . 
         [0008]    A block diagram illustrating exemplary BS  102  is shown in  FIG. 2 . BS  102  is equipped with WiMAX communication function only, which is configured of WiMAX PHY block  130  and WiMAX MAC block  120 . WiMAX MAC block  120  implements WiMAX OFDMA (Orthogonal Frequency Division Multiple Access)-based media access control protocols. WiMAX PHY block  130  implements the WiMAX OFDMA-based physical layer protocols under the control of WiMAX MAC block  120 . 
         [0009]    With reference to  FIG. 2 , WiMAX MAC block  120  further is configured of control section  122 , scheduler  124 , message generation section  126 , and message processing section  128 . Control section  122  controls general MAC protocol operations. Scheduler  124  schedules the allocation of resources to the MSs under the control of control section  122 . Message generation section  126  receives resource allocation scheduling information from scheduler  124  and then generates data packets and DL control information. Message processing section  128  analyzes data packets and UL control information received from the plurality of MSs under the control of control section  122  and reports its analysis result to control section  122 . 
         [0010]    Note that data packets and DL control information generated by message generation section  126  are transmitted by BS  102  to the plurality of MSs via an OFDMA transmitter (not shown in  FIG. 2 ) inside WiMAX PHY block  130 . Data packets and UL control information analyzed by message processing section  128  are received by BS  102  via an OFDMA receiver (not shown in  FIG. 2 ) inside WiMAX PHY block  130 . 
         [0011]    With reference to  FIG. 2 , there are HFBCH (HARQ Feedback Channel) generation section  132  and resource allocation generation section  134  inside message generation section  126 , where HARQ stands for Hybrid Automatic Repeat Request. 
         [0000]    HFBCH generation section  132  generates HARQ feedback channels for UL data transmission, which carry HARQ feedback information (e.g., ACK/NACK) for UL data transmission. Resource allocation generation section  134  generates resource allocation control information for DL/UL data transmission, which carries resource allocation information for each of the plurality of MSs. 
         [0012]    In terms of GRA (Group Resource Allocation), resource allocation control information generated by resource allocation generation section  134  may contain group configuration information as well as group resource allocation information including indexing information of HFBCH for DL/UL GRA transmission. The HFBCHs generated by HFBCH generation section  132  may contain HARQ feedback information for UL GRA transmission. 
         [0013]    With reference to  FIG. 2 , there exists HFBCH analyzing section  136  inside message processing section  128 . HFBCH analyzing section  136  analyzes the received HFBCHs for DL data transmission and determines whether the corresponding DL data transmission is successful or not. In terms of GRA, HFBCH analyzing section  136  may derive HARQ feedback information for DL GRA transmission from the received UL control information. 
         [0014]    A block diagram illustrating exemplary MS  104  is shown in  FIG. 3 . MS  104  is equipped with both WiMAX and Wi-Fi communication functions, which is configured of WiMAX PHY block  142 , Wi-Fi PHY block  144 , WiMAX MAC block  146 , Wi-Fi MAC block  148 , and GLL (Generic Link Layer) block  150 . WiMAX MAC block  146  implements WiMAX OFDMA-based MAC (media access control) protocols. WiMAX PHY block  142  implements the WiMAX OFDMA-based physical layer protocols, under the control of WiMAX MAC block  146 . Wi-Fi MAC block  148  implements Wi-Fi CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance)-based MAC (media access control) protocols. Wi-Fi PHY block  144  implements the Wi-Fi OFDM (Orthogonal Frequency Division Multiplexing)/DSSS (Direct Sequence Spread Spectrum)-based physical layer protocols, under the control of Wi-Fi MAC block  148 . GLL block  150  functions as managing interworking between heterogeneous WiMAX and Wi-Fi links. 
         [0015]    With reference to  FIG. 3 , WiMAX MAC block  146  further is configured of control section  154 , message generation section  152 , and message processing section  156 . Control section  154  controls general MAC protocol operations. Message generation section  152  generates UL control information and data packets under the control of control section  154 . Message processing section  156  analyzes data packets and DL control information received from BS  102  under the control of control section  154 , and provides its analysis result to control section  154 . 
         [0016]    Note that data packets and UL control information generated by message generation section  152  are transmitted from MS  104  to BS  102  via an OFDMA transmitter (not shown in  FIG. 3 ) inside WiMAX PHY block  142 . Data packets and DL control information analyzed by message processing section  156  are received by MS  104  via an OFDMA receiver (not shown in  FIG. 3 ) inside WiMAX PHY block  142 . 
         [0017]    With reference to  FIG. 3 , there are resource analyzing section  151  and HFBCH analyzing section  153  inside message processing section  156 . HFBCH analyzing section  153  analyzes the received HFBCHs for UL data transmission and determines whether the corresponding UL data transmission is successful or not. Resource analyzing section  151  analyzes the received resource allocation control information and derives the resource allocation information specific to MS  104 . In case of UL data transmission, data packet generated by message generation section  152  under the control of control section  154  will then be transmitted by MS  104  to BS  102  according to the derived resource allocation information. In case of DL data transmission, data packet transmitted by BS  102  to MS  104  will then be received by MS  104  according to the derived resource allocation information. 
         [0018]    In terms of GRA, resource analyzing section  151  inside message processing section  156  may derive group configuration information as well as group resource allocation information including indexing information of HFBCH for DL/UL GRA transmission from received resource allocation control information. HFBCH analyzing section  153  may derive HARQ feedback information for UL GRA transmission from the received HFBCHs. 
         [0019]    With reference to  FIG. 3 , there exists HFBCH generation section  155  inside message generation section  152 . HFBCH generation section  155  generates HARQ feedback channels, which include HARQ feedback information, for DL data transmission. In terms of GRA, HFBCH generation section  155  may generate HARQ feedback channels for DL GRA transmission. 
         [0020]    A block diagram illustrating exemplary MS  106  is shown in  FIG. 4 . MS  106  is also equipped with both WiMAX and Wi-Fi communication functions, which has a very similar structure and functionality as MS  104 . A main difference between MS  104  and MS  106  is that unlike MS  106 , there is scheduler  158  inside Wi-Fi MAC block  148  of MS  104  as shown in  FIG. 3 , which is used for cooperation scheduling for CliCo. 
         [0021]    With reference to  FIG. 1 , BS  102  communicates with MS  104  via WiMAX links  108   a  and  108   b , and communicates with MS  106  via WiMAX links  110   a  and  110   b . MS  104  communicates with MS  106  via peer-to-peer Wi-Fi links  112   a  and  112   b . Alternatively, MS  104  may communicate with MS  106  via other radio technologies if available, such as WiMAX, Bluetooth, or 60 GHz mmW (Millimeter Wave). 
         [0022]    Note that CliCo can be implemented in both DL and UL of wireless communication system  100 . As an example, the operation of UL CliCo in wireless communication system  100  is described below. 
         [0023]    With reference to  FIG. 1 , when the signal quality of WiMAX link  108   a  between BS  102  and MS  104  becomes poor, MS  104  may start the UL CliCo procedure such as neighbor discovery and cooperator selection/allocation. If the signal quality of WiMAX link  110   a  between BS  102  and MS  106  is good, MS  104  may select MS  106  as its cooperator. In the context of CliCo, MS  104  is called originating MS, and MS  106  is called cooperating MS. 
         [0024]    CliCo may happen in various scenarios. For example, originating MS  104  may be deep inside a cafeteria and thus the signal quality of WiMAX links for originating MS  104  may be very poor. However, cooperating MS  106  may be much closer to window or entrance of the cafeteria than originating MS  104 , and thus cooperating MS  106  may have a much better signal quality of WiMAX links than originating MS  104 . 
         [0025]    A diagram illustrating an exemplary frame structure  200  is shown in  FIG. 5 , which can be applied to wireless communication system  100  with CliCo as shown in  FIG. 1 . With reference to  FIG. 5 , each of frame  202  and frame  212  is configured of eight subframes. Five of them are DL subframes, and the others are UL subframes. 
         [0026]    So far as UL CliCo is concerned, during first DL subframe  204  of frame  202 , BS  102  may transmit MAP  220  indicating control information to a plurality of MSs connected to BS  102 , including originating MS  104  and cooperating MS  106  engaged in CliCo. MAP  220  is configured of a plurality of MAP IEs (Information Elements). Some of MAP IEs may carry HARQ feedback information for UL data transmission; and some of MAP IEs may carry resource allocation information for DL/UL data transmission. One MAP IE in MAP  220  carrying HARQ feedback information forms one HBFCH for UL data transmission. 
         [0027]    During time period  208  between first DL subframe  204  and first UL subframe  206  of frame  202 , originating MS  104  and cooperating MS  106 , respectively, need to decode MAP  220  to obtain their resource allocation information including HFBCH indexing information. Also originating MS  104  needs to transmit UL data burst  250  to cooperating MS  106  via peer-to-peer Wi-Fi link  112   a.    
         [0028]    During first UL subframe  206  of frame  202 , if originating MS  104  successfully decodes MAP  220  sent by BS  102  via WiMAX link  108   b , it will transmit UL data burst  250  to BS  102  via WiMAX link  108   a  according to its received resource allocation information. On the other hand, if cooperating MS  106  successfully decodes MAP  220  sent by BS  102  via WiMAX link  110   b  and successfully receives UL data burst  250  sent by originating MS  104  via peer-to-peer Wi-Fi link  112   a , cooperating MS  106  will simultaneously transmit the same UL data burst  250  to BS  102  via WiMAX link  110   a  according to its received resource allocation information. Consequently BS  102  can combine two copies of UL data burst  250  received from WiMAX link  108   a  and WiMAX link  110   a  to improve the quality of received signal. 
         [0029]    During second DL subframe  214  of frame  212 , BS  102  may transmit MAP  240  to the plurality of MSs connected to BS  102 , including originating MS  104  and cooperating MS  106  engaged in CliCo. As mentioned above, some of HFBCHs in MAP  240  may carry HARQ feedback information for UL data burst  250  transmitted by originating MS  104  and cooperating MS  106  during first UL subframe  206  of frame  202 . 
         [0030]    During time period  218  between second DL subframe  214  and first UL subframe  216  of frame  212 , originating MS  104  and cooperating MS  106 , respectively, need to decode the corresponding HFBCHs in MAP  240  to obtain their HARQ feedback information for UL data burst  250  according to their HFBCH indexing information which are obtained by decoding MAP  220  during time period  208 . 
         [0031]    During first UL subframe  216  of frame  212 , if the HARQ feedback information implies that BS  102  does not successfully decode UL data burst  250  transmitted by originating MS  104  and cooperating MS  106  during first UL subframe  206  of frame  202 , originating MS  104  and cooperating MS  106  may need to retransmit UL data burst  250 . 
         [0032]    As mentioned above, future 802.16/WiMAX networks should support explosive mobile data traffic. Furthermore, future 802.16/WiMAX networks should provide enhanced quality of experience for mobile internet applications, such as VoIP (Voice over Internet Protocol). Considering VoIP has a periodic traffic pattern and with relatively fixed payload size, various PHY/MAC mechanisms have been designed especially to improve quality of experience for VoIP such as PA (Persistent Allocation) and GRA. In the present invention, the application of GRA to CliCo is addressed. 
         [0033]    GRA mechanism specified in the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1) does not deal with CliCo. However, GRA mechanism can be applied to CliCo in a straightforward manner. 
         [0034]    According to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), GRA mechanism allocates resources to multiple users as a group in order to save control overhead. This resource allocation is performed per transport flow. With reference to  FIG. 1 , the method of applying GRA to CliCo is configured of two operations: That is, i) BS  102  adds flows of originating MS  104  and cooperating MS  106  into a group or deletes flows of originating MS  104  and cooperating MS  106  from a group. 
         [0000]    ii) BS  102  allocates resources to the flows of originating MS  104  and cooperating MS  106  within the same group. 
         [0035]    According to the IEEE 802.16m draft standard (e.g., see non-Patent Literature 1), when adding a flow of originating MS  104  (or cooperating MS  106 ) into a group, BS  102  transmits group configuration information in a unicast MAC control message to originating MS  104  (or cooperating MS  106 ). When allocating resources to the flows of originating MS  104  and/or cooperating MS  106  within the group, BS  102  transmits group resource allocation information including HFBCH indexing information in a multicast MAP IE to originating MS  104  and cooperating MS  106 . Note that group configuration information transmitted in the unicast MAC control message and group resource allocation information transmitted in the multicast MAP IE are generated by message generation section  126  as shown in  FIG. 2 . 
         [0036]    According to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), the group configuration information transmitted in the unicast MAC control message can be used to interpret the group resource allocation information transmitted in the corresponding multicast MAP IE. The content of the group configuration information includes:
       Flow identifier;   User bitmap size;   UBI (User Bitmap Index);   Group identifier;   Allocation periodicity; and   MIMO (Multiple Input Multiple Output) mode set or the like       
 
         [0043]    The flow identifier is used to inform an MS which of its flows is added into a group, which has a size of 4 bits. The user bitmap size indicates the number of bits used for user bitmap transmitted in the multicast MAP IE. The user bitmap size may be one of 4 bits, 8 bits, 16 bits, and 32 bits. The UBI indicates the index of the flow of MS in the user bitmap, which has a size of 5 bits. The group identifier uniquely identifies the DL/UL group to which the flow of MS is added, which has a size of 12 bits. The allocation periodicity specifies how often the multicast MAP IE carrying the corresponding group resource allocation information is transmitted, which may be one of 1 frame, 2 frames, 4 frames, and 8 frames. The MIMO mode set signals MIMO modes supported in the group. 
         [0044]    A main difference between the group configuration information for originating MS  104  and cooperating MS  106  is that the UBIs of originating MS  104  and cooperating MS  106  are different. Furthermore, since the group configuration information is unicast to originating MS  104  and cooperating MS  106 , respectively, cooperating MS  106  does not know the UBI of originating MS  104 ; vice versa. 
         [0045]    According to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), the group configuration information may further include a set of four HARQ burst sizes. For example, the set of four HARQ burst sizes may be {6 bytes, 8 bytes, 9 bytes, 10 bytes}. Note that the burst size is the size of encoded packet which may be partitioned into a plurality of FEC (Forward Error Correction) blocks. The burst size may include the addition of CRC (Cyclic Redundancy Code) per burst and/or per FEC block when applicable. 
         [0046]    Corresponding to each of four HARQ burst sizes, the group configuration information may also include a set of eight resource sizes. For example, for the HARQ burst size of 9 bytes, the set of eight resource sizes may be {1 LRU, 2 LRUs, 3 LRUs, 4 LRUs, 5 LRUs, 6 LRUs, 7 LRUs, 8 LRUs} where LRU stands for Logical Resource Unit. For each of other three HARQ burst sizes of 6 bytes, 8 bytes and 10 bytes, the set of eight resource sizes may be different or the same as the HARQ burst size of 9 bytes. 
         [0047]    According to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), a portion of the group resource allocation information is carried by bitmaps transmitted in the multicast MAP IE. A diagram illustrating exemplary bitmaps carrying partial group resource allocation information according to the IEEE 802.16m draft standard (Non-Patent Literature 1) is shown in  FIG. 6 . There are two bitmaps used to carry partial group resource allocation information. One is user bitmap  302 , and the other is resource allocation bitmap  304 . 
         [0048]    According to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), user bitmap  302  uses 1 bit per flow to signal which flows are scheduled in the current frame. With reference to  FIG. 6 , the UBI of originating MS  104  is “00000”, and therefore the first bit of user bitmap  302  is referenced. The UBI of cooperating MS  106  is “00011” and so the fourth bit of user bitmap  302  is referenced. So the flows (corresponding to data) of both originating MS  104  and cooperating MS  106  are specified by resource allocation map  304  and transmitted to the current frame. 
         [0049]    With reference to  FIG. 6 , resource allocation bitmap  304  is configured of a plurality of 5-bit resource allocation indications, each of which is for a specific scheduled flow. In each of 5-bit resource allocation indications, the first 2 bits is used to signal HARQ burst size and the last 3 bits is used to signal resource size. 
         [0050]    With reference to  FIG. 6 , the HARQ burst sizes are selected from among four burst sizes {6 bytes, 8 bytes, 9 bytes, 10 bytes} and indicated by “00,” “01,” “10” and “11.” 
         [0000]    In  FIG. 6 , both originating MS  104  and cooperating MS  106  are indicated by “10” and therefore both HARQ burst sizes are 9 bytes. 
         [0051]    The resource sizes of originating MS  104  and cooperating MS  106  are indicated by “111” and “001”, respectively. So the resource sizes of originating MS  104  and cooperating MS  106  may be 8 LRUs and 2 LRUs, respectively. 
         [0052]    According to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), in addition to user bitmap  302  and resource allocation bitmap  304 , another bitmap called MIMO bitmap may be used if multiple MIMO modes are supported in a group. 
         [0053]    A table illustrating an exemplary GRA MAP IE for transmitting the group resource allocation information according to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1) is shown in Table 1. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Size 
                   
               
               
                 Syntax 
                 (bit) 
                 Description/Notes 
               
               
                   
               
             
             
               
                 GRA_MAP_IE( ){ 
                   
                   
               
               
                 MAP IE type 
                 4 
                 GRA MAP IE 
               
               
                 User bitmap 
                 Variable 
                 Indicate scheduled MSs in a 
               
               
                   
                   
                 group. 
               
               
                   
                   
                 The size of the bitmap is equal 
               
               
                   
                   
                 to the User Bitmap Size signaled 
               
               
                   
                   
                 to each MS in the group 
               
               
                   
                   
                 configuration information. 
               
               
                 Resources Offset 
                 7 
                 Indicate starting LRU for 
               
               
                   
                   
                 resource allocation to this 
               
               
                   
                   
                 group. 
               
               
                 HFA offset 
                 6 
                 Indicate the start of the HFBCH 
               
               
                   
                   
                 index used for scheduled 
               
               
                   
                   
                 allocations. 
               
               
                 Resource 
                 Variable 
                 Indicate the HARQ burst 
               
               
                 Allocation Bitmap 
                   
                 size/resource size for each of 
               
               
                   
                   
                 scheduled MSs. 
               
               
                 ... 
               
               
                 } 
               
               
                   
               
             
          
         
       
     
         [0054]    In addition, according to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), the HFBCH index for a scheduled flow in a group is a predetermined function of its UBI and the HFA offset as shown in Table 1. In other words, each of originating MS  104  and cooperating MS  106  can compute its HFBCH index according to its UBI after decoding the GRA MAP IE as shown in Table 1. 
         [0055]    A flowchart illustrating method  400  of receiving resource allocation information at originating MS  104  (or cooperating MS  106 ) according to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1) is shown in  FIG. 7 . Method  400  starts at Step  402 . At Step  404 , originating MS  104  (or cooperating MS  106 ) checks the user bitmap according to its UBI. At Step  406 , originating MS  104  (or cooperating MS  106 ) determines whether its flow is scheduled in the current frame. If the flow of originating MS  104  (or cooperating MS  106 ) is scheduled in the current frame, at Step  408 , it proceeds to check the resource allocation bitmap to derive its HARQ burst size and resource size according to its UBI. After that, at Step  410 , originating MS  104  (or cooperating MS  106 ) computes its HFBCH index according to its UBI. At Step  406 , if the flow of originating MS  104  (or cooperating MS  106 ) is not scheduled in the current frame, method  400  stops at Step  412 . 
       CITATION LIST 
     Non-Patent Literature 
     NPL 1 
       [0000]    
       
         IEEE P802.16m/D5, DRAFT Amendment to IEEE Standard for local and metropolitan area networks—Part 16: Air Interface for Broadband Wireless Access Systems—Advanced Air Interface 
       
     
       NPL 2 
       [0000]    
       
         IEEE C802.16-10/0016r1, Future 802.16 Networks: Challenges and Possibilities 
       
     
       NPL 3 
       [0000]    
       
         IEEE C802.16-10/0005r1, Client Cooperation in Future Wireless Broadband Networks 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0059]    According to the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1), both originating MS  104  and cooperating MS  106  engaged in CliCo handle the same data burst. One HFBCH for both originating MS  104  and cooperating MS  106  is enough. However, due to different UBIs in the same group, originating MS  104  and cooperating MS  106  have two different HFBCHs. This would waste valuable HFBCH resource. 
         [0060]    It is an object of the present invention to provide a base station, a mobile station, a cooperating mobile station, a transmission method and a reception method capable of avoiding unnecessary HFBCH resource waste by using one HBCH for a plurality of MSs that deals with the same data burst. 
       Solution to Problem 
       [0061]    In accordance with an aspect of the present invention, a base station (BS) that communicates with a plurality of mobile stations (MSs), employs a configuration including: a control signal generation section that generates control signals indicative of resource allocation information for each of the plurality of MSs, and a transmission section that transmits the control signals to the plurality of MSs, in which a control signal for a mobile station (MS) contains information on another MS. 
         [0062]    In accordance with an aspect of the present invention, a BS communicates with a plurality of MSs including an originating MS and a cooperating MS, which is exploited to communicate between the BS and the originating MS, and includes: a control signal generation section that generates control signals indicative of resource allocation information for each of the plurality of MSs, and a transmission section that transmits the control signals to the plurality of MSs, in which a control signal for the cooperating MS contains information on the originating MS. 
         [0063]    In accordance with an aspect of the present invention, when a flow of the cooperating MS is added into a same group as the originating MS, the control signal for the cooperating MS contains information on the originating MS. 
         [0064]    In accordance with an aspect of the present invention, the information on the originating MS is contained into resource allocation information for the cooperating MS. 
         [0065]    In accordance with an aspect of the present invention, the information on the originating MS is replaced with burst size information for the cooperating MS. 
         [0066]    In accordance with an aspect of the present invention, the number of bits of the information on the originating MS varies depending on the number of MSs which belong to a same group as the originating MS. 
         [0067]    In accordance with an aspect of the present invention, the number of bits of the information on the originating MS varies with increasing of the number of bits of the burst size information for the cooperating MS and with decreasing of the number of bits of the resource size information for the cooperating MS, depending on the number of MSs which belong to a same group as the originating MS. 
         [0068]    In accordance with an aspect of the present invention, if the number of bits of the resource size information for the cooperating MS is decreased, an actual resource size of the cooperating MS results from a bitwise operation of a resource size of the originating MS and a nominal resource size of the cooperating MS. 
         [0069]    In accordance with an aspect of the present invention, a resource size of the cooperating MS is same as that of the originating MS, and the information on the originating MS is replaced with burst size information and resource size information for the cooperating MS. 
         [0070]    In accordance with an aspect of the present invention, an actual resource size of the cooperating MS results from a bitwise operation of a resource size of the originating MS and a nominal resource size of the cooperating MS. 
         [0071]    In accordance with an aspect of the present invention, a resource size of the cooperating MS is set to a predetermined size, and the information on the originating MS is replaced with burst size information and resource size information for the cooperating MS. 
         [0072]    In accordance with an aspect of the present invention, the information on the originating MS is identification information of the originating MS. 
         [0073]    In accordance with an aspect of the present invention, the information on the originating MS is an offset of identification information of the originating MS relative to identification information of the cooperating MS. 
         [0074]    In accordance with an aspect of the present invention, an MS includes: a reception section that receives a control signal for the MS containing information on another MS; and a resource calculating section that computes a transmission resource according to the control signal and the information on the other MS. 
         [0075]    In accordance with an aspect of the present invention, a cooperating MS exploited to communicate between a BS and an originating MS includes: a reception section that receives a control signal for the cooperating MS containing information on the originating MS; a resource calculating section that computes a transmission resource according to the control signal and the information on the originating MS; and a transmission section that transmits a signal received from the originating MS, to the BS via the transmission resource. 
         [0076]    In accordance with an aspect of the present invention, if the information on the originating MS indicates identification information of the cooperating MS, the transmission section stops transmitting the signal to the BS. 
         [0077]    In accordance with an aspect of the present invention, if the information on the originating MS indicates identification information of the cooperating MS, the transmission section stops transmitting the signal to the BS for a predetermined or configurable time period. 
         [0078]    In accordance with an aspect of the present invention, a part of the information on the originating MS is contained into resource allocation information for the cooperating MS and other part of the information on the originating MS is contained into group configuration information sent to the cooperating MS. 
         [0079]    In accordance with an aspect of the present invention, a transmission method performed in a BS which communicates with a plurality of MSs includes: generating control signals indicative of resource allocation information for each of the plurality of MSs, and transmitting the control signals to the plurality of MSs, in which a control signal for a MS contains information on another MS. 
         [0080]    In accordance with an aspect of the present invention, a transmission method performed in a BS which communicates with a plurality of MSs including an originating MS and a cooperating MS, which is exploited to communicate between the BS and the originating MS includes: generating control signals indicative of resource allocation information for each of the plurality of MSs, and transmitting the control signals to the plurality of MSs, in which a control signal for the cooperating MS contains information on the originating MS. 
         [0081]    In accordance with an aspect of the present invention, a reception method performed in an MS includes: receiving a control signal for the MS containing information on another MS; and computing a transmission resource according to the control signal and the information on the other MS. 
         [0082]    In accordance with an aspect of the present invention, a reception method performed in a cooperating MS exploited to communicate between a BS and an originating MS includes: receiving a control signal for the cooperating MS containing information on the originating MS; computing a transmission resource according to the control signal and the information on the originating MS; and transmitting a signal received from the originating MS, to the BS via the transmission resource. 
         [0083]    These and other features and advantages of the present invention will be better understood with reference to the following detailed description of the present invention, along with the accompanying figures, and appended claims. 
       Advantageous Effects of Invention 
       [0084]    The invention uses one HFBCH for a plurality of MSs which handles the same data burst, so that unnecessary HFBCH resource waste can be avoided. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0085]      FIG. 1  shows a diagram illustrating an exemplary wireless communication system with CliCo (Client Collaboration); 
           [0086]      FIG. 2  shows a block diagram illustrating an exemplary BS (Base Station); 
           [0087]      FIG. 3  shows a block diagram illustrating an exemplary originating MS (Mobile Station); 
           [0088]      FIG. 4  shows a block diagram illustrating an exemplary cooperating MS (Mobile Station); 
           [0089]      FIG. 5  shows a diagram illustrating an exemplary frame structure; 
           [0090]      FIG. 6  shows a diagram illustrating exemplary bitmaps for carrying partial group resource allocation information according to the prior art; 
           [0091]      FIG. 7  shows a flowchart illustrating a method of receiving group resource allocation information at the originating MS (or cooperating MS) according to the prior art; 
           [0092]      FIG. 8  shows a flowchart illustrating a method of receiving group resource allocation information at a cooperating MS according to Embodiment 1 of the present invention; 
           [0093]      FIG. 9  shows a diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 4-bit user bitmap according to Embodiment 2 of the present invention; 
           [0094]      FIG. 10  shows a flowchart illustrating a method of receiving group resource allocation information in case of 4-bit user bitmap at the cooperating MS according to Embodiment 2 of the present invention; 
           [0095]      FIG. 11  shows a diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 8-bit user bitmap according to Embodiment 2 of the present invention; 
           [0096]      FIG. 12  shows a flowchart illustrating a method of receiving group resource allocation information in case of 8-bit user bitmap at the cooperating MS according to Embodiment 2 of the present invention; 
           [0097]      FIG. 13  shows a diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 32-bit user bitmap according to Embodiment 2 of the present invention; 
           [0098]      FIG. 14  shows a flowchart illustrating a method of receiving group resource allocation information in case of 32-bit user bitmap at the cooperating MS according to Embodiment 2 of the present invention; 
           [0099]      FIG. 15  shows a diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 4-bit user bitmap according to Embodiment 3 of the present invention; 
           [0100]      FIG. 16  shows a diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 8-bit user bitmap according to Embodiment 4 of the present invention; and 
           [0101]      FIG. 17  shows a diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 8-bit user bitmap according to Embodiment 5 of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0102]    Various embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for clarity and conciseness. 
       Embodiment 1 
       [0103]    According to Embodiment 1 of the present invention, with reference to  FIG. 1 , a basic idea of the method of applying GRA to CliCo is that BS  102  shares the UBI of originating MS  104  with cooperating MS  106  using the group configuration information. In more details, when BS  102  adds a flow of cooperating MS  106  into a group, the group configuration information unicast by BS  102  to cooperating MS  106  also includes the UBI of originating MS  104 . The content of the group configuration information unicast by BS  102  to cooperating MS  106  can be described below:
       Flow identifier of cooperating MS  106 ;   User bitmap size;   UBI of originating MS  104 ;   UBI of cooperating MS  106 ;   Group identifier;   Allocation periodicity; and   MIMO mode set or the like.       
 
         [0111]    According to Embodiment 1 of the present invention, since cooperating MS  106  knows the UBI of originating MS  104 , cooperating MS  106  is able to use the UBI of originating MS  104  instead of its own UBI to derive its HFBCH index. As a result, only an identical HFBCH is allocated for both originating MS  104  and cooperating MS  106  engaged in CliCo. So unnecessary HFBCH resource waste is avoided. 
         [0112]    A flowchart illustrating method  500  for receiving resource scheduling information at cooperating MS  106  according to Embodiment 1 of the present invention is shown in  FIG. 8 . Method  500  starts at Step  502 . At Step  504 , cooperating MS  106  checks the user bitmap according to its UBI. At Step  506 , cooperating MS  106  determines whether its flow is scheduled in the current frame or not. If the flow of cooperating MS  106  is scheduled in the current frame, at Step  508 , it proceeds to check the resource allocation bitmap to derive its HARQ burst size and resource size according to its UBI. At Step  510 , cooperating MS  106  computes its HFBCH index according to the UBI of originating MS  104 . At Step  506 , if the flow of cooperating MS  106  is not scheduled in the current frame, method  500  stops at Step  512 . 
         [0113]    According to Embodiment 1 of the present invention, the content of group configuration information unicast by BS  102  to originating MS  104 , and the content of group resource allocation information multicast by BS  102  to originating MS  104  and cooperating MS  106  are the same as the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1). However, the content of group configuration information unicast by BS  102  to cooperating MS  106  is different from the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1). 
         [0114]    According to Embodiment 1 of the present invention, an alternative is that the group configuration information is multicast by BS  102  to both originating MS  104  and cooperating MS  106 . The content of the group configuration information multicast by BS  102  to both originating MS  104  and cooperating MS  106  can be described below:
       Flow identifier of originating MS  104 ;   Flow identifier of cooperating MS  106 ;   User bitmap size;   UBI of originating MS  104 ;   UBI of cooperating MS  106 ;   Group identifier;   Allocation periodicity; and   MIMO mode set or the like.       
 
         [0123]    According to Embodiment 1 of the present invention, the group configuration information can be transmitted in either a MAC control message or a MAP IE. 
       Embodiment 2 
       [0124]    According to Embodiment 1 of the present invention, a demerit is that extra control overhead may be introduced in group configuration information before starting group resource allocation due to sharing the UBI of originating MS  104  with cooperating MS  106 . 
         [0125]    With reference to  FIG. 1 , as mentioned above, originating MS  104  and cooperating MS  106  engaged in CliCo handle the same data burst, and thus have the same HARQ burst size. So HARQ burst size indication for one of originating MS  104  and cooperating MS  106  is redundant. In addition, the length of UBI which is actually required depends on the user bitmap size. For example, if the user bitmap size is 8 bits, only 3-bit UBI is really required instead of 5-bit UBI. 
         [0126]    According to Embodiment 2 of the present invention, a basic idea of the method of applying GRA to CliCo is that BS  102  shares the UBI of originating MS  104  with cooperating MS  106  using the group resource allocation information instead of the group configuration information in Embodiment 1 of the present invention. In more details, when BS  102  allocates resources to originating MS  104  and cooperating MS  106 , a variable portion of the 5-bit resource allocation indication for cooperating MS  106  in resource allocation bitmap is used to indicate the UBI of originating MS  104 . The length of the variable portion depends on the user bitmap size. The remaining portion in the 5-bit resource allocation indication for cooperating MS  106  is used to indicate its resource size. However, the ways for indicating the resource size of cooperating MS  106  are different, depending on the user bitmap size. 
         [0127]    According to Embodiment 2 of the present invention, since the UBI of originating MS  104  is embedded in resource allocation bitmap, no extra control overhead is introduced in group configuration information. 
         [0128]    A diagram illustrating exemplary bitmaps carrying partial group resource allocation information in case of 4-bit user bitmap according to Embodiment 2 of the present invention is shown in  FIG. 9 . With reference to  FIG. 9 , in resource allocation bitmap  604 , the first 2 bits (e.g., “00”) of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the UBI of originating MS  104  instead of the HARQ burst size of cooperating MS  106 , and the last 3 bits (e.g. “010”) are used to signal the resource size for cooperating MS  106 . Note that the first 2 bits (e.g., “10”) of 5-bit resource allocation indication for originating MS  104  are used to signal the HARQ burst size of both originating MS  104  and cooperating MS  106 . 
         [0129]    A flowchart illustrating method  700  for receiving group resource allocation information at cooperating MS  106  in case of 4-bit user bitmap according to Embodiment 2 of the present invention is shown in  FIG. 10 . Method  700  starts at Step  702 . At Step  704 , cooperating MS  106  checks the user bitmap according to its UBI. At Step  706 , cooperating MS  106  determines whether its flow is scheduled in the current frame. If the flow of cooperating MS  106  is scheduled in the current frame, at Step  708 , it proceeds to check the resource allocation bitmap to derive the UBI of originating MS  104  and its resource size according to its UBI. At Step  710 , cooperating MS  106  proceeds to check the resource allocation bitmap again to derive its HARQ burst size according to the UBI of originating MS  104 . At Step  712 , cooperating MS  106  then computes its HFBCH index according to the UBI of originating MS  104 . At Step  706 , if the flow of cooperating MS  106  is not scheduled in the current frame, method  700  stops at Step  714 . 
         [0130]    A diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 8-bit user bitmap according to Embodiment 2 of the present invention is shown in  FIG. 11 . With reference to  FIG. 11 , in resource allocation bitmap  804 , the first 3 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the UBI of originating MS  104 , and the last 2 bits are used to indicate the nominal resource size of cooperating MS  106  instead of the actual resource size of cooperating MS  106 . 
         [0131]    There are various ways of calculating the actual resource size indication of cooperating MS  106  from its nominal resource indication. In one way, the actual resource size indication of cooperating MS  106  may result from a bitwise XOR operation of the resource size indication of originating MS  104  and the nominal resource size indication of cooperating MS  106 . With reference to  FIG. 11 , the resource size indication of originating MS  104  is “111”, and the nominal resource size indication of cooperating MS  106  is “01”. So the actual resource size indication of cooperating MS  106  is “111 XOR 01=110”. In another way, the actual resource size indication of cooperating MS  106  may result from a bitwise OR or AND operation of the resource size indication of originating MS  104  and the nominal resource size indication of cooperating MS  106 . 
         [0132]    A flowchart illustrating method  900  for receiving group resource allocation information at cooperating MS  106  in case of 8-bit user bitmap according to Embodiment 2 of the present invention is shown in  FIG. 12 . Method  900  starts at Step  902 . At Step  904 , cooperating MS  106  checks the user bitmap according to its UBI. At Step  906 , cooperating MS  106  determines whether its flow is scheduled in the current frame. If the flow of cooperating MS  106  is scheduled in the current frame, at Step  908 , it proceeds to check the resource allocation bitmap to derive the UBI of originating MS  104 . At Step  910 , cooperating MS  106  proceeds to check the resource allocation bitmap again to derive its HARQ burst size and resource size according to its UBI and the UBI of originating MS  104 . At Step  912 , cooperating MS  106  then computes its HFBCH index according to the UBI of originating MS  104 . At Step  906 , if the flow of cooperating MS  106  is not scheduled in the current frame, method  900  stops at Step  914 . 
         [0133]    According to Embodiment 2 of the present invention, similar to the case of 8-bit user bitmap, in case of 16-bit user bitmap, in the resource allocation bitmap, the first 4 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the UBI of originating MS  104 , and the last 1 bit is used to indicate the nominal resource size of cooperating MS  106  instead of the actual resource size of cooperating MS  106 . 
         [0134]    A diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 32-bit user bitmap according to Embodiment 2 of the present invention is shown in  FIG. 13 . With reference to  FIG. 13 , in resource allocation bitmap  1004 , the whole 5-bit resource allocation indication for cooperating MS  106  is used to indicate the UBI of originating MS  104 . The resource size of cooperating MS  106  is signaled by the 3-bit resource size indication for originating MS  104 . In other words, in case of 32-bit user bitmap, originating MS  104  and cooperating MS  106  have always the same resource size. 
         [0135]    A table illustrating an exemplary GRA MAP IE for transmitting the group resource allocation information according to Embodiment 2 of the present invention is shown in Table 2. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Syntax 
                 Size (bit) 
                 Description/Notes 
               
               
                   
               
             
             
               
                 GRA_MAP_IE( ){ 
                   
                   
               
               
                 MAP IE Type 
                 4 
                 GRA MAP IE 
               
               
                 User Bitmap 
                 Variable 
                 Indicate scheduled MSs in a 
               
               
                   
                   
                 group. The size of the bitmap is 
               
               
                   
                   
                 equal to the User Bitmap Size 
               
               
                   
                   
                 signaled to each MS in the 
               
               
                   
                   
                 group configuration 
               
               
                   
                   
                 information 
               
               
                 Resources Offset 
                 7 
                 Indicate starting LRU for 
               
               
                   
                   
                 resource allocation to this 
               
               
                   
                   
                 group 
               
               
                 HFA Offset 
                 6 
                 Indicate the start of the HFBCH 
               
               
                   
                   
                 index used for scheduled 
               
               
                   
                   
                 allocations 
               
               
                 Resource 
                 Variable 
                 Indicate the UBI of the 
               
               
                 Allocation Bitmap 
                   
                 corresponding originating 
               
               
                   
                   
                 MS/resource size for scheduled 
               
               
                   
                   
                 cooperating MS and indicate 
               
               
                   
                   
                 the HARQ burst size/resource 
               
               
                   
                   
                 size for each of other scheduled 
               
               
                   
                   
                 MSs. Note that the ways of 
               
               
                   
                   
                 indicating the resource size for 
               
               
                   
                   
                 scheduled cooperating MS 
               
               
                   
                   
                 depends on the User Bitmap 
               
               
                   
                   
                 Size 
               
               
                 ... 
               
               
                 } 
               
               
                   
               
             
          
         
       
     
         [0136]    A flowchart illustrating method  1100  for receiving group resource allocation information at cooperating MS  106  in case of 32-bit user bitmap according to Embodiment 2 of the present invention is shown in  FIG. 14 . Method  1100  starts at Step  1102 . At Step  1104 , cooperating MS  106  checks the user bitmap according to its UBI. At Step  1106 , cooperating MS  106  determines whether its flow is scheduled in the current frame. If the flow of cooperating MS  106  is scheduled in the current frame, at Step  1108 , it proceeds to check the resource allocation bitmap to derive the UBI of originating MS  104 . At Step  1110 , cooperating MS  106  proceeds to check the resource allocation bitmap again to derive its HARQ burst size and resource size according to the UBI of originating MS  104 . At Step  1112 , cooperating MS  106  then computes its HFBCH index according to the UBI of originating MS  104 . At Step  1106 , if the flow of cooperating MS  106  is not scheduled in the current frame, method  1100  stops at Step  1114 . 
         [0137]    From the perspective of cooperating MS  106 , the difference among methods  700 ,  900  and  1100  is the way of deriving its resource size. In method  700 , the resource size of cooperating MS  106  is derived according to its own UBI. In method  900 , the resource size of cooperating MS  106  is derived according to its own UBI and the UBI of originating MS  104 . In method  1100 , the resource size of cooperating MS  106  is derived according to the UBI of originating MS  104  only. 
         [0138]    According to Embodiment 2 of the present invention, an alternative in case of 8-bit user bitmap is that in the resource allocation bitmap, the first 3 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the UBI of originating MS  104  and the last 2 bits are used to directly signal the actual resource size of cooperating MS  106  instead of the nominal resource size of cooperating MS  106 . Similarly, an alternative in case of 16-bit user bitmaps is that in the resource allocation bitmap, the first 4 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the UBI of originating MS  104 , and the last 1 bit is used to indicate the actual resource size of cooperating MS  106 . 
         [0139]    According to Embodiment 2 of the present invention, an alternative in case of 4-bit user bitmap is that in the resource allocation bitmap, the first 2 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the UBI of originating MS  104 , and the last 3 bits are used to indicate the nominal resource size of cooperating MS  106  instead of the actual resource size of cooperating MS  106 . The actual resource size indication of cooperating MS  106  can be derived from the resource size indication of originating MS  104  and the nominal resource size indication of cooperating MS  106  in the above-mentioned manners. 
         [0140]    According to Embodiment 2 of the present invention, an alternative in case of 32-bit user bitmap is that the whole 5-bit resource allocation indication of cooperating MS  106  in the resource allocation bitmap is used to signal the UBI of originating MS  104 , but the resource size of cooperating MS  106  is always set to a predetermined value. 
         [0141]    According to Embodiment 2 of the present invention, the content of group configuration information unicast by BS  102  to originating MS  104  or cooperating MS  106  is the same as the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1). However, the content of group resource allocation information multicast by BS  102  to originating MS  104  or cooperating MS  106  is different from the IEEE 802.16m draft standard (e.g., see Non-Patent Literature 1). 
         [0142]    According to Embodiment 2 of the present invention, the group resource allocation information can be transmitted in either multicast MAC control information or a multicast MAP IE. 
       Embodiment 3 
       [0143]    According to Embodiments 1 and 2 of the present invention, the UBI indication of originating MS  104  in resource allocation bitmap is assumed to be different from the UBI of cooperating MS  106 . In the following, the case that the UBI indication of originating MS  104  in resource allocation bitmap is the same as the UBI of cooperating MS  106  is addressed. 
         [0144]    A diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 4-bit user bitmap according to Embodiment 3 of the present invention is shown in  FIG. 15 . With reference to  FIG. 15 , in resource allocation bitmap  1204 , the first 2 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the UBI of originating MS  104 . If the UBI indication of originating MS  104  (e.g. “10”) is the same as the UBI of cooperating MS  106 , various implications may be incurred. For example, this may imply that corresponding MS  106  will not transmit/receive the UL/DL data burst in the following N consecutive allocation periods, where N is predetermined. Alternatively, the value of N is indicated by the last 3 bits of 5-bit resource allocation indication for cooperating MS  106 . Alternatively, this may imply that cooperating MS  106  will no longer transmit/receive the UL/DL data burst. 
         [0145]    According to Embodiment 3 of the present invention, in case of 8-bit, 16-bit or 32-bit user bitmap, if the UBI indication of originating MS  104  in resource allocation bitmap is the same as the UBI of cooperating MS  106 , implications similar to those in the case of 4-bit user bitmap may be incurred. 
       Embodiment 4 
       [0146]    According to Embodiments 1, 2 and 3 of the present invention, the length of the UBI indication of originating MS  104  is dependent on the user bitmap size. As a result, in case of 4-bit user bitmap, 3 bits can be used to signal the resource size of cooperating MS  106 . Thus a full set of 8 resource sizes can be used for allocating resources to cooperating MS  106 . However, in case of 8-bit, 16-bit, or 32-bit user bitmap, only a subset of 8 resource sizes can be used for allocating resources to cooperating MS  106 . This would decrease the scheduling flexibility of BS  102 . 
         [0147]    A diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 8-bit user bitmap according to Embodiment 4 of the present invention is shown in  FIG. 16 . With reference to  FIG. 16 , in resource allocation bitmap  1304 , only the first 2 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate the offset of the UBI of originating MS  104  relative to the UBI of cooperating MS  106 , and the last 3 bits are used to indicate the resource size of cooperating MS  106 . 
         [0148]    A table illustrating an exemplary GRA MAP IE for transmitting the group resource allocation information according to Embodiment 4 of the present invention is shown in Table 3. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Size 
                   
               
               
                 Syntax 
                 (bit) 
                 Description/Notes 
               
               
                   
               
             
             
               
                 GRA_MAP_IE( ){ 
                   
                   
               
               
                 MAP IE Type 
                 4 
                 GRA MAP IE 
               
               
                 User Bitmap 
                 Variable 
                 Indicate scheduled MSs in a 
               
               
                   
                   
                 group. The size of the bitmap is 
               
               
                   
                   
                 equal to the User Bitmap Size 
               
               
                   
                   
                 signaled to each MS in the group 
               
               
                   
                   
                 configuration information 
               
               
                 Resource Offset 
                 7 
                 Indicate starting LRU for 
               
               
                   
                   
                 resource allocation to this 
               
               
                   
                   
                 group 
               
               
                 HFA offset 
                 6 
                 Indicate the start of the HFBCH 
               
               
                   
                   
                 index used for scheduled 
               
               
                   
                   
                 allocations 
               
               
                 Resource 
                 Variable 
                 Indicate the UBI offset of 
               
               
                 Allocation Bitmap 
                   
                 corresponding originating MS 
               
               
                   
                   
                 relative to scheduled 
               
               
                   
                   
                 cooperating MS/resource size 
               
               
                   
                   
                 for scheduled cooperating MS 
               
               
                   
                   
                 and indicate the HARQ burst 
               
               
                   
                   
                 size/resource size for each of 
               
               
                   
                   
                 other scheduled MSs. 
               
               
                 ... 
               
               
                 } 
               
               
                   
               
             
          
         
       
     
         [0149]    According to Embodiment 4 of the present invention, since only 2 bits are used for the UBI indication of originating MS  104  in case of 8-bit, 16-bit, or 32-bit user bitmap, various constraints need to be imposed when BS  102  adds flows of originating MS  104  and cooperating MS  106  into a group. For example, BS  102  may suffer the following constraints when adding flows of originating MS  104  and cooperating MS  106  into a group:
       the UBI of originating MS  104  is smaller than the UBI of cooperating MS  106 ; and   The difference between the UBIs of originating MS  104  and cooperating MS  106  is not larger than 4.       
 
         [0152]    According to Embodiment 4 of the present invention, since 3 bits are used to indicate the resource size of cooperating MS  106 , a full set of 8 resource sizes can be used for allocating resources to cooperating MS  106 , even in case of 8-bit, 16-bit, or 32-bit user bitmap. 
       Embodiment 5 
       [0153]    According to Embodiment 4 of the present invention, some constraints need to be imposed when BS  102  adds the flows of originating MS  104  and cooperating MS  106  into a group. This may decrease group configuration flexibility of BS  102 . 
         [0154]    A diagram illustrating exemplary bitmaps for carrying partial group resource allocation information in case of 8-bit user bitmap according to Embodiment 5 of the present invention is shown in  FIG. 17 . With reference to  FIG. 17 , in resource allocation bitmap  1404 , the first 2 bits of 5-bit resource allocation indication for cooperating MS  106  are used to indicate a first portion of the UBI of originating MS  104  and the last 3 bits are used to indicate the resource size of cooperating MS  106 . 
         [0155]    A table illustrating an exemplary GRA MAP IE for transmitting the group resource allocation information according to Embodiment 5 of the present invention is shown in Table 4. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                   
                 Size 
                   
               
               
                 Syntax 
                 (bit) 
                 Description/Notes 
               
               
                   
               
             
             
               
                 GRA_MAP_IE( ){ 
                   
                   
               
               
                 MAP IE Type 
                 4 
                 GRA MAP IE 
               
               
                 User Bitmap 
                 Variable 
                 Indicate scheduled MSs in a 
               
               
                   
                   
                 group. The size of the bitmap 
               
               
                   
                   
                 is equal to the User Bitmap 
               
               
                   
                   
                 Size signaled to each MS in the 
               
               
                   
                   
                 group configuration 
               
               
                   
                   
                 information 
               
               
                 Resource Offset 
                 7 
                 Indicate starting LRU for 
               
               
                   
                   
                 resource allocation to this 
               
               
                   
                   
                 group 
               
               
                 HFA Offset 
                 6 
                 Indicate the start of the 
               
               
                   
                   
                 HFBCH index used for 
               
               
                   
                   
                 scheduled allocations 
               
               
                 Resource 
                 Variable 
                 Indicate a first portion of UBI 
               
               
                 Allocation Bitmap 
                   
                 of the corresponding 
               
               
                   
                   
                 originating MS/resource size 
               
               
                   
                   
                 for scheduled cooperating MS 
               
               
                   
                   
                 and indicate the HARQ burst 
               
               
                   
                   
                 size/resource size for each of 
               
               
                   
                   
                 other scheduled MSs. 
               
               
                 ... 
               
               
                 } 
               
               
                   
               
             
          
         
       
     
         [0156]    According to Embodiment 5 of the present invention, the group configuration information unicast by BS  102  to cooperating MS  106  includes a second portion of the UBI of originating MS  104 . The content of the group configuration information unicast by BS  102  to cooperating MS  106  can be described below:
       Flow identifier of cooperating MS  106 ;   User bitmap size;   A second portion of the UBI of originating MS  104 ;   UBI of cooperating MS  106 ;   Group ID;   Allocation periodicity; and   MIMO mode set or the like.       
 
         [0164]    According to Embodiment 5 of the present invention, since 3 bits carried in group configuration information and group resource allocation information are used for the UBI indication of originating MS  104  in case of 8-bit user bitmap, no constraints need to be imposed when BS  102  adds the flows of originating MS  104  and cooperating MS  106  into a group. 
         [0165]    According to Embodiment 5 of the present invention, the first portion of the UBI of originating MS  104  may be 2 LSBs (Least Significant Bits) of the UBI of originating MS  104 . The second portion of the UBI of originating MS  104  may be 1 MSB (Most Significant Bit), 2 MSBs and 3 MSBs of the UBI of originating MS  104  in case of 8-bit, 16-bit and 32-bit user bitmap, respectively. 
         [0166]    According to Embodiment 5 of the present invention, alternatively the first portion of the UBI of originating MS  104  may be 2 MSBs of the UBI of originating MS  104 . The second portion of the UBI of originating MS  104  may be 1 LSB, 2 LSBs and 3 LSBs of the UBI of originating MS  104  in case of 8-bit, 16-bit and 32-bit user bitmap, respectively. According to the above-mentioned embodiments of the present invention, BS  102  shares the UBI of originating MS  104  with cooperating MS  106  such that cooperating MS  106  is able to use the UBI of originating MS  104  to calculate its HFBCH index. It will be naturally appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention, in which BS  102  shares the UBI of cooperating MS  106  with originating MS  104 . 
         [0167]    According to the above-mentioned embodiments of the present invention, in addition to originating MS  104 , only one cooperating MS  106  is involved in CliCo. It will be naturally appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention, in which more than one cooperating MSs involve in CliCo, and BS  102  shares the UBI of one of the originating MS and the cooperating MSs engaged in CliCo with the others. 
         [0168]    It will be naturally appreciated by a person skilled in the art that other numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive. 
         [0169]    Although cases have been described with the above embodiments as examples where the present invention is configured by hardware, the present invention can also be realized by software in interworking with hardware. 
         [0170]    Each function block employed in the description of each of the aforementioned embodiments may typically be implemented as an LSI constituted by an integrated circuit. These may be individual chips or partially or totally contained on a single chip. 
         [0000]    “LSI” is adopted here but this may also be referred to as “IC,” “system LSI,” “super LSI,” or “ultra LSI” depending on differing extents of integration. 
         [0171]    Further, the method of circuit integration is not limited to LSI&#39;s, and implementation using dedicated circuitry or general purpose processors is also possible. After LSI manufacture, utilization of a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor where connections and settings of circuit cells within an LSI can be reconfigured is also possible. 
         [0172]    Further, if integrated circuit technology comes out to replace LSI&#39;s as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Application of biotechnology is also possible. 
         [0173]    The disclosure of Japanese Patent Application No. 2010-097026, filed on Apr. 20, 2010, including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0174]    The present invention is applicable to a mobile communication system or the like.