Control channel allocation method, control channel searching method and communication apparatus using the same

Abstract

UE-specific search spaces (UE-SS) for a carrier-aggregated communication system are introduced to decrease the number of blind decoding attempts, decrease downlink control information (DCI) blocking probability, and maintain good blind decoding performance. In the proposed control channel allocation method, the control channel searching method and the communication apparatus thereof, the UE-specific search spaces are extended except control channel element (CCE) aggregation level one. Further, a new CCE aggregation level is created in the UE-specific search spaces. The sum of the number of control channel candidates for all aggregation levels is bounded by the maximum number of PDCCH candidates. In addition, uplink MIMO grant command is just allocated in a pre-configured component carrier or a set of pre-configured component carriers, but uplink MIMO grant command is not allocated in the remaining component carriers.

1 . A control channel allocation method in a communication system with multiple component carriers, the method comprising:
 determining to encode a UE-specific DCI into one of aggregation levels l 1 , l 2 , l 3 , l 4  and l 5  according to at least system bandwidth, UE signal-to-noise ratio or signal-to-interference-plus-noise-ratio requirement on corresponding transmission mode;   allocating the encoded UE-specific DCI in the UE-specific search spaces a, b, c, d and e corresponding to the aggregation levels l 1 , l 2 , l 3 , l 4  and l 5 ; and   transmitting the subframe comprising the allocated UE-specific DCI.   
     
     
         2 . The method according to  claim 1 , wherein the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs; and the fifth aggregation level is that the UE-specific DCI is encoded into l 5  CCEs. 
     
     
         3 . The method according to  claim 1 , wherein the fifth aggregation level is that the UE-specific DCI is encoded into l 5  of CCEs and l 5  is a non-negative integer to be selected from a set of 3, 5, 6, 7 and any other positive integer greater than 8. 
     
     
         4 . The method according to  claim 1 , wherein the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, the number of control channel candidates for the fourth aggregation level is d, and the number of control channel candidates for the fifth aggregation level is e, wherein a, b, c, d and e are non-negative integers restricted to the following inequality (1):
     a+b+c+d+e≦N   BD    inequality (1),
   wherein, N BD  is the maximum number of PDCCH candidates.   
     
     
         5 . The method according to  claim 1 , wherein l 1 , l 2 , l 3 , l 4 , l 5  are respectively 1, 2, 4, 8, 12. 
     
     
         6 . The method according to  claim 1 , wherein a, b, c, d, e are respectively 0, 6, 2, 2, 2. 
     
     
         7 . The method according to  claim 1 , wherein a, b, c, d, e are respectively 0, 6, 4, 2, 2. 
     
     
         8 . A control channel allocation method in a communication system with multiple component carriers, the method comprising:
 determining to encode a UE-specific DCI into one of aggregation levels l 1 , l 2 , l 3  and l 4 , according to system bandwidth, UE signal-to-noise ratio or signal-to-interference-plus-noise-ratio requirement on corresponding transmission mode;   allocating the encoded UE-specific DCI in the UE-specific search space a, b, c and d corresponding to the aggregation levels l 1 , l 2 , l 3  and l 4 ; and   transmitting the subframe comprising the allocated UE-specific DCI.   
     
     
         9 . The method according to  claim 8 , wherein the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; and the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs. 
     
     
         10 . The method according to  claim 8 , wherein a is a non-negative integer less than 6. 
     
     
         11 . The method according to  claim 8 , wherein the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, and the number of control channel candidates for the fourth aggregation level is d, wherein a, b, c and d are non-negative integers restricted to the following inequality (1):
     a+b+c+d≦N   BD    inequality (1),
   wherein, N BD  is the maximum number of PDCCH candidates.   
     
     
         12 . The method according to  claim 8 , wherein l 1 , l 2 , l 3  and l 4  are respectively 1, 2, 4, 8. 
     
     
         13 . The method according to  claim 8 , wherein a, b, c and d are respectively 0, 6, 2, 2. 
     
     
         14 . The method according to  claim 8 , wherein a, b, c and d are respectively 0, 8, 2, 2. 
     
     
         15 . The method according to  claim 8 , wherein a, b, c and d are respectively 0, 6, 4, 2. 
     
     
         16 . The method according to  claim 8 , wherein a, b, c and d are respectively 0, 8, 4, 2. 
     
     
         17 . The method according to  claim 8 , wherein a, b, c and d are respectively 0, 6, 6, 2. 
     
     
         18 . The method according to  claim 8 , wherein a, b, c and d are respectively 0, 8, 6, 2. 
     
     
         19 . A control channel searching method in a communication system with multiple component carriers, applied for a UE to search for UE-specific DCI in a subframe from a base station, the method comprising:
 receiving a control region from the base station;   determining to search a UE-specific DCI in the UE-specific search space a, b, c, d and e corresponding to aggregation levels l 1 , l 2 , l 3 , l 4  and l 5 ; and   decoding the UE-specific DCI in the subframe by using the monitoring DCI formats, where the monitoring DCI formats are depending on transmission mode.   
     
     
         20 . The method according to  claim 19  wherein the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs; and the fifth aggregation level is that the UE-specific DCI is encoded into l 5  CCEs. 
     
     
         21 . The method according to  claim 19 , wherein the fifth aggregation level is that the UE-specific DCI is encoded into l 5  of CCEs, wherein l 5  is a non-negative integer to be selected from a set of 3, 5, 6 and 7 and any other positive integer greater than 8. 
     
     
         22 . The method according to  claim 19 , wherein the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, the number of control channel candidates for the fourth aggregation level is d, and the number of control channel candidates for the fifth aggregation level is e wherein a, b, c, d and e are non-negative integers restricted to the following inequality (1):
     a+b+c+d+e≦N   BD    inequality (1),
   wherein N BD  is the maximum number of PDCCH candidates.   
     
     
         23 . The method according to  claim 19 , wherein l 1 , l 2 , l 3 , l 4  and l 5  are respectively 1, 2, 4, 8, 12. 
     
     
         24 . The method according to  claim 19 , wherein a, b, c, d and e are respectively 0, 6, 2, 2, 2. 
     
     
         25 . The method according to  claim 19 , wherein a, b, c, d and e are respectively 0, 6, 4, 2, 2. 
     
     
         26 . A control channel searching method in a communication system, with multiple component carriers, applied for a UE to search for UE-specific DCI in a subframe from a base station, the method comprising:
 receiving a control region from the base station;   determining to search a UE-specific DCI in the UE-specific search space a, b, c, and d corresponding to aggregation level l 1 , l 2 , l 3  and l 4 ; and   decoding the UE-specific DCI in the subframe by the monitoring DCI formats depending on transmission mode.   
     
     
         27 . The method according to  claim 26 , wherein, the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; and the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs. 
     
     
         28 . The method according to  claim 26 , wherein, a is a non-negative integer less than 6. 
     
     
         29 . The method according to  claim 26 , wherein, the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, and the number of control channel candidates for the fourth aggregation level is d, wherein a, b, c and d are non-negative integers restricted to the following inequality (1):
     a+b+c+d≦N   BD    inequality (1),
   wherein, N BD  is the maximum number of PDCCH candidates.   
     
     
         30 . The method according to  claim 26 , wherein l 1 , l 2 , l 3  and l 4  are respectively 1, 2, 4, 8. 
     
     
         31 . The method according to  claim 26 , wherein a, b, c and d are respectively 0, 6, 2, 2. 
     
     
         32 . The method according to  claim 26 , wherein a, b, c and d are respectively 0, 8, 2, 2. 
     
     
         33 . The method according to  claim 26 , wherein a, b, c and d are respectively 0, 6, 4, 2. 
     
     
         34 . The method according to  claim 26 , wherein a, b, c and d are respectively 0, 8, 4, 2. 
     
     
         35 . The method according to  claim 26 , wherein a, b, c and d are respectively 0, 6, 6, 2. 
     
     
         36 . The method according to  claim 26 , wherein a, b, c and d are respectively 0, 8, 6, 2. 
     
     
         37 . A control channel allocation method, applied to allocate uplink MIMO grant command in a communication system, with multiple component carriers, the method comprising:
 allocating uplink MIMO grant command just in a first set of component carriers but allocating no uplink MIMO grant command in a second set of component carriers, wherein the second set of component carriers includes at least one component carrier.   
     
     
         38 . The method according to  claim 37 , wherein the first set of component carriers is a primary component carrier. 
     
     
         39 . The method according to  claim 37 , wherein the first set of component carriers is a pre-configured secondary component carrier. 
     
     
         40 . The method according to  claim 37 , wherein the first set of component carriers is a set of pre-configured component carriers. 
     
     
         41 . A control channel searching method, applied for a UE to search uplink MIMO grant command in a communication system with multiple component carriers, the method comprising:
 decoding uplink MIMO grant command just in a first set of component carriers but decoding no uplink MIMO grant command in a second set of component carriers, wherein the second set of component carriers includes at least one component carrier.   
     
     
         42 . The method according to  claim 41 , wherein the first set of component carriers is a primary component carrier. 
     
     
         43 . The method according to  claim 41 , wherein the first set of component carriers is a pre-configured secondary component carrier. 
     
     
         44 . The method according to  claim 41 , wherein the first set of component carriers is a set of pre-configured component carriers. 
     
     
         45 . A communication apparatus, comprising:
 a determination unit, configured for determining to encode a UE-specific DCI into one of aggregation levels l 1 , l 2 , l 3 , l 4  and l 5  according to at least system bandwidth, UE signal-to-noise ratio or signal-to-interference-plus-noise ratio requirement on corresponding transmission mode;   a protocol stack module, connected to the determination unit, configured for allocating the encoded UE-specific DCI in the UE-specific search spaces a, b, c, d and e corresponding to the aggregation levels l 1 , l 2 , l 3 , l 4  and l 5 ; and   a transceiver module, connected to the protocol stack module, configured for transmitting multi-component-carrier signal comprising the allocated UE-specific DCI.   
     
     
         46 . The apparatus according to  claim 45 , wherein the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs; and the fifth aggregation level is that the UE-specific DCI is encoded into l 5  CCEs. 
     
     
         47 . The apparatus according to  claim 45 , wherein the fifth aggregation level is that the UE-specific DCI is encoded into l 5  of CCEs and l 5  is a non-negative integer to be selected from a set of 3, 5, 6, 7 and any other positive integer greater than 8. 
     
     
         48 . The apparatus according to  claim 45 , wherein the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, the number of control channel candidates for the fourth aggregation level is d, and the number of control channel candidates for the fifth aggregation level is e, wherein a, b, c, d and e are non-negative integers restricted to the following inequality (1):
     a+b+c+d+e≦N   BD    inequality (1),
   wherein, N BD  is the maximum number of PDCCH candidates.   
     
     
         49 . The apparatus according to  claim 45 , wherein l 1 , l 2 , l 3 , l 4 , l 5  are respectively 1, 2, 4, 8, 12. 
     
     
         50 . The apparatus according to  claim 45 , wherein a, b, c, d, e are respectively 0, 6, 2, 2, 2. 
     
     
         51 . The apparatus according to  claim 45 , wherein a, b, c, d, e are respectively 0, 6, 4, 2, 2. 
     
     
         52 . The apparatus according to  claim 45 , wherein the communication apparatus is an enhanced node B (eNodeB), advanced base station (ABS), macro-cell, pico-cell, or remote radio head (RRH). 
     
     
         53 . A communication apparatus, comprising:
 a determination unit, configured for determining to encode a UE-specific DCI into one of aggregation levels l 1 , l 2 , l 3  and l 4  according to system bandwidth, UE signal-to-noise ratio or signal-to-interference-plus-noise-ratio requirement on corresponding transmission mode;   a protocol stack module, connected to the determination unit, configured for allocating the encoded UE-specific DCI in the UE-specific search spaces a, b, c and d corresponding to the aggregation levels l 1 , l 2 , l 3  and l 4 ; and   a transceiver module, connected to the protocol stack module, configured for transmitting multi-component-carrier signal comprising the allocated UE-specific DCI.   
     
     
         54 . The apparatus according to  claim 53 , wherein the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; and the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs. 
     
     
         55 . The apparatus according to  claim 53 , wherein a is a non-negative integer less than 6. 
     
     
         56 . The apparatus according to  claim 53 , wherein the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, and the number of control channel candidates for the fourth aggregation level is d, wherein a, b, c and d are non-negative integers restricted to the following inequality (1):
     a+b+c+d≦N   BD    inequality (1),
   wherein N BD  is the maximum number of PDCCH candidates.   
     
     
         57 . The apparatus according to  claim 53 , wherein l 1 , l 2 , l 3  and l 4  are respectively 1, 2, 4, 8. 
     
     
         58 . The apparatus according to  claim 53 , wherein a, b, c and d are respectively 0, 6, 2, 2. 
     
     
         59 . The apparatus according to  claim 53 , wherein a, b, c and d are respectively 0, 8, 2, 2. 
     
     
         60 . The apparatus according to  claim 53  wherein a, b, c and d are respectively 0, 6, 4, 2. 
     
     
         61 . The apparatus according to  claim 53 , wherein a, b, c and d are respectively 0, 8, 4, 2. 
     
     
         62 . The apparatus according to  claim 53 , wherein a, b, c and d are respectively 0, 6, 6, 2. 
     
     
         63 . The apparatus according to  claim 53 , wherein a, b, c and d are respectively 0, 8, 6, 2. 
     
     
         64 . The apparatus according to  claim 53 , wherein the communication apparatus is an enhanced node B (eNodeB), advanced base station (ABS), macro-cell, pico-cell, or remote radio head (RRH). 
     
     
         65 . A communication apparatus, comprising:
 a protocol stack module, configured for allocating uplink MIMO grant command just in a first set of component carriers but allocating no uplink MIMO grant command in a second set of component carriers, wherein the second set of component carriers includes at least one component carrier; and   a transceiver module, connected to the protocol stack module, configured for transmitting multi-component-carrier signal comprising the allocated uplink MIMO grant command.   
     
     
         66 . The apparatus according to  claim 65 , wherein the first set of component carriers is a primary component carrier. 
     
     
         67 . The apparatus according to  claim 65 , wherein the first set of component carriers is a pre-configured secondary component carrier. 
     
     
         68 . The apparatus according to  claim 65 , wherein the first set of component carriers is a set of pre-configured component carriers. 
     
     
         69 . The apparatus according to  claim 65 , wherein the communication apparatus is an enhanced node B (eNodeB), advanced base station (ABS), macro-cell, pico-cell, or remote radio head (RRH). 
     
     
         70 . A communication apparatus, applied to search UE-specific DCI in a subframe from a base station in a communication system with multi-component-carriers, the apparatus comprising:
 a transceiver module, configured for receiving multi-component-carrier signal comprising the UE-specific DCI from the base station;   a protocol stack module, connected to the transceiver module, configured for storing the received signal of the UE-specific search space;   a determination unit, connected to the protocol stack module, configured for determining to decode the UE-specific DCI format in the UE-specific search spaces a, b, c, d and e corresponding to the aggregation levels l 1 , l 2 , l 3 , l 4  and l 5 ; and   a decoding unit, connected to the determination unit, configured for decoding a UE-specific DCI in the subframe by using the monitoring DCI formats, where the monitoring DCI formats are depending on transmission mode.   
     
     
         71 . The apparatus according to  claim 70  wherein the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs; and the fifth aggregation level is that the UE-specific DCI is encoded into l 5  CCEs. 
     
     
         72 . The apparatus according to  claim 70 , wherein the fifth aggregation level is that the UE-specific DCI is encoded into l 5  of CCEs, wherein l 5  is a non-negative integer to be selected from a set of 3, 5, 6 and 7 and any other positive integer greater than 8. 
     
     
         73 . The apparatus according to  claim 70 , wherein the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, the number of control channel candidates for the fourth aggregation level is d, and the number of control channel candidates for the fifth aggregation level is e wherein a, b, c, d and e are non-negative integers restricted to the following inequality (1):
     a+b+c+d+e≦N   BD    inequality (1),
   wherein N BD  is the maximum number of PDCCH candidates.   
     
     
         74 . The apparatus according to  claim 70 , wherein l 1 , l 2 , l 3 , l 4  and l 5  are respectively 1, 2, 4, 8, 12. 
     
     
         75 . The apparatus according to  claim 70 , wherein a, b, c, d and e are respectively 0, 6, 2, 2, 2. 
     
     
         76 . The apparatus according to  claim 70 , wherein a, b, c, d and e are respectively 0, 6, 4, 2, 2. 
     
     
         77 . The apparatus according to  claim 70 , wherein the communication apparatus is a user equipment (UE), a mobile phone, a smartphone, a personal computer (PC), a notebook PC, a netbook PC, a tablet PC, a television, a set-top-box, a wireless data modem, a game console, a portable device, or a portable multimedia player. 
     
     
         78 . A communication apparatus, applied to search UE-specific DCI in a subframe from a base station in a communication system with receiving multi-component-carriers, the apparatus comprising:
 a transceiver module, configured for receiving multi-component-carrier signal comprising the UE-specific DCI from the base station;   a protocol stack module, connected to the transceiver module, configured for storing the UE-specific search space in the subframe;   a determination unit, connected to the protocol stack module, configured for searching the UE-specific DCI in the UE-specific search spaces a, b, c, and d corresponding to the aggregation levels l 1 , l 2 , l 3 , and l 4 ; and   a decoding unit, connected to the determination unit, configured for determining to decode a UE-specific DCI in the subframe by the monitoring DCI formats depending on transmission mode.   
     
     
         79 . The apparatus according to  claim 78 , wherein, the first aggregation level is that the UE-specific DCI is encoded into one control channel element (CCE); the second aggregation level is that the UE-specific DCI is encoded into two CCEs; the third aggregation level is that the UE-specific DCI is encoded into four CCEs; and the fourth aggregation level is that the UE-specific DCI is encoded into eight CCEs. 
     
     
         80 . The apparatus according to  claim 78 , wherein, a is a non-negative integer less than 6. 
     
     
         81 . The apparatus according to  claim 78 , wherein, the number of control channel candidates for the first aggregation level is a, the number of control channel candidates for the second aggregation level is b, the number of control channel candidates for the third aggregation level is c, and the number of control channel candidates for the fourth aggregation level is d, wherein a, b, c and d are non-negative integers restricted to the following inequality (1):
     a+b+c+d≦N   BD    inequality (1),
   wherein, N BD  is the maximum number of PDCCH candidates.   
     
     
         82 . The apparatus according to  claim 78 , wherein l 1 , l 2 , l 3  and l 4  are respectively 1, 2, 4, 8. 
     
     
         83 . The apparatus according to  claim 78  wherein a, b, c and d are respectively 0, 6, 2, 2. 
     
     
         84 . The apparatus according to  claim 78 , wherein a, b, c and d are respectively 0, 8, 2, 2. 
     
     
         85 . The apparatus according to  claim 78 , wherein a, b, c and d are respectively 0, 6, 4, 2. 
     
     
         86 . The apparatus according to  claim 78 , wherein a, b, c and d are respectively 0, 8, 4, 2. 
     
     
         87 . The apparatus according to  claim 78 , wherein a, b, c and d are respectively 0, 6, 6, 2. 
     
     
         88 . The apparatus according to  claim 78 , wherein a, b, c and d are respectively 0, 8, 6, 2. 
     
     
         89 . The apparatus according to  claim 78 , wherein the communication apparatus is a user equipment (UE), a mobile phone, a smartphone, a personal computer (PC), a notebook PC, a netbook PC, a tablet PC, a television, a set-top-box, a wireless data modem, a game console, a portable device, or a portable multimedia player. 
     
     
         90 . A communication apparatus, applied to search uplink MIMO grant command in a subframe from a base station in a communication system with multi-component-carriers, the apparatus comprising:
 a transceiver module, configured for receiving multi-component-carrier signal comprising the uplink MIMO grant command from the base station; and   a protocol stack module, configured for monitoring uplink MIMO grant command just in a first set of component carriers but monitoring no uplink MIMO grant command in a second set of component carriers, wherein the second set of component carriers includes at least one component carrier.   
     
     
         91 . The apparatus according to  claim 90 , wherein the first set of component carriers is a primary component carrier. 
     
     
         92 . The apparatus according to  claim 90 , wherein the first set of component carriers is a pre-configured secondary component carrier. 
     
     
         93 . The apparatus according to  claim 90 , wherein the first set of component carriers is a set of pre-configured component carriers. 
     
     
         94 . The apparatus according to  claim 90 , wherein the communication apparatus is a user equipment (UE), a mobile phone, a smartphone, a personal computer (PC), a notebook PC, a netbook PC, a tablet PC, a television, a set-top-box, a wireless data modem, a game console, a portable device, or a portable multimedia player.