Method, base station, and user equipment for transmitting downlink control signal

Abstract

The application pertains to a method for transmitting a downlink control signal. A base station maps an enhanced physical downlink control channel (E-PDCCH) sequentially to resource elements for transmitting the E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of OFDM symbols used by the E-PDCCH of a user equipment (UE). The E-PDCCH is sent to the UE from the base station by using the resource elements, where the E-PDCCH and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH are frequency-division multiplexed. Because the E-PDCCH is mapped sequentially to resource elements for transmitting the E-PDCCH in each OFDM symbol according to an order of OFDM symbols used by the E-PDCCH of the UE, different control channel elements of E-PDCCHs at different aggregation levels will not include a same E-PDCCH modulation symbol, thereby ensuring that the UE judges a start position of the E-PDCCH correctly.

1 - 68 . (canceled) 
     
     
         69 . A method for transmitting a downlink control signal, comprising:
 mapping, by a base station, an enhanced physical downlink control channel (E-PDCCH) of a user equipment (UE) sequentially to resource elements for transmitting the E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the E-PDCCH of the UE; and   sending, by the base station, the E-PDCCH to the UE by using the mapped resource elements;   wherein the E-PDCCH and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH are frequency-division multiplexed.   
     
     
         70 . The method according to  claim 69 , wherein mapping the E-PDCCH sequentially to the resource elements comprises:
 mapping the E-PDCCH sequentially to resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the E-PDCCH in the OFDM symbol, wherein L is an integer.   
     
     
         71 . The method according to  claim 70 , wherein mapping the E-PDCCH sequentially to the resource elements occupied by the L control channel elements in each OFDM symbol comprises:
 mapping modulation symbols of the E-PDCCH with index numbers of   
       
         
           
             
               
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       sequentially to a set R l  of resource elements,
 wherein the set R l  is a set of resource elements occupied by the l th  control channel element among the L control channel elements comprised in the E-PDCCH in the OFDM symbol; j 0  is a start position of the modulation symbols of the E-PDCCH mapped in the OFDM symbol; N l  is the quantity of the resource elements in the set R l ; and N l , j 0 , l and q are integers. 
 
     
     
         72 . The method according to  claim 69 , wherein mapping the E-PDCCH sequentially to the resource elements comprises:
 mapping the E-PDCCH sequentially to resource elements occupied by L control channel elements allocated to the E-PDCCH according to an order of subcarriers in each OFDM symbol, wherein L is an integer.   
     
     
         73 . The method according to  claim 72 , wherein mapping the E-PDCCH sequentially to the resource elements occupied by L control channel elements allocated to the E-PDCCH comprises:
 mapping modulation symbols of the E-PDCCH with index numbers of j 0 +[0, . . . , N−1] sequentially to a set R of resource elements,   wherein j 0  is a start position of the modulation symbols of the E-PDCCH mapped in the OFDM symbol; the set R is a set of resource elements occupied by the L control channel elements comprised in the E-PDCCH in the OFDM symbol; N is the quantity of the resource elements in the set R; and N and j 0  are integers.   
     
     
         74 . A method for receiving a downlink control signal, comprising:
 receiving, by a user equipment (UE), a downlink subframe from a base station;   extracting, by the UE, modulation symbols of a candidate enhanced physical downlink control channel (E-PDCCH) sequentially from resource elements mapped to the candidate E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the candidate E-PDCCH in the downlink subframe; and   performing a decoding and a cyclic redundancy check (CRC) on the candidate E-PDCCH;   wherein the E-PDCCH of the UE and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH of the UE are frequency-division multiplexed.   
     
     
         75 . The method according to  claim 74 , wherein extracting the modulation symbols of the candidate E-PDCCH comprises:
 extracting the modulation symbols of the candidate E-PDCCH sequentially from resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the E-PDCCH in the OFDM symbol, wherein L is an integer.   
     
     
         76 . The method according to  claim 75 , wherein extracting the modulation symbols of the candidate E-PDCCH sequentially from resource elements occupied by the L control channel elements in each OFDM symbol comprises:
 extracting modulation symbols of the candidate E-PDCCH and with index numbers of   
       
         
           
             
               
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       from a set R l  of resource elements,
 wherein the set R l  is a set of resource elements occupied by the l th  control channel element among the L control channel elements comprised in the modulation symbols of the candidate E-PDCCH in the OFDM symbol; j 0  is a start position of the modulation symbols of the candidate E-PDCCH mapped in the OFDM symbol; N l  is the quantity of the resource elements in the set R l ; and N l , j 0 , l and q are integers. 
 
     
     
         77 . The method according to  claim 74 , wherein extracting the modulation symbols of the candidate E-PDCCH comprises:
 extracting, by the UE, the modulation symbols of the candidate E-PDCCH from resource elements occupied by L control channel elements allocated to the candidate E-PDCCH according to an order of subcarriers in each OFDM symbol.   
     
     
         78 . The method according to  claim 77 , wherein extracting the modulation symbols of the candidate E-PDCCH from resource elements occupied by L control channel elements allocated to the candidate E-PDCCH comprises:
 extracting modulation symbols of the candidate E-PDCCH and with index numbers of j 0 +[0, . . . , N−1] from a set R of resource elements,   wherein j 0  is a start position of the modulation symbols of the candidate E-PDCCH mapped in the OFDM symbol; the set R is a set of resource elements occupied by the L control channel elements comprised in the modulation symbols of the candidate E-PDCCH in the OFDM symbol; N is the quantity of the resource elements in the set R; and N and j 0  are integers.   
     
     
         79 . A base station, comprising:
 a mapping processor, configured to map an enhanced physical downlink control channel (E-PDCCH) of a user equipment (UE) sequentially to resource elements for transmitting the E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the E-PDCCH of the UE; and   a transmitter, configured to send the E-PDCCH to the UE by using the mapped resource elements;   wherein the E-PDCCH and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH are frequency-division multiplexed.   
     
     
         80 . The base station according to  claim 79 , wherein the mapping processor maps the E-PDCCH sequentially to resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the E-PDCCH in the OFDM symbol, wherein L is an integer. 
     
     
         81 . The base station according to  claim 79 , wherein the mapping processor maps the E-PDCCH sequentially to resource elements occupied by L control channel elements allocated to the E-PDCCH according to an order of subcarriers in each OFDM symbol. 
     
     
         82 . A user equipment, comprising:
 a receiver, configured to receive a downlink subframe from a base station; and   an extracting processor, configured to sequentially extract modulation symbols of a candidate enhanced physical downlink control channel (E-PDCCH) sequentially from resource elements mapped to the candidate E-PDCCH in each orthogonal frequency division multiplexing (OFDM) symbol according to an order of the OFDM symbols used by the candidate E-PDCCH in the downlink subframe, and perform a decoding and a cyclic redundancy check (CRC) on the candidate E-PDCCH;   wherein an E-PDCCH of the user equipment and a physical downlink shared channel (PDSCH) invoked by the E-PDCCH of the user equipment are frequency-division multiplexed.   
     
     
         83 . The user equipment according to  claim 82 , wherein the extracting processor extracts the candidate E-PDCCH sequentially from resource elements occupied by L control channel elements in each OFDM symbol according to an order of the L control channel elements allocated to the candidate E-PDCCH in the OFDM symbol, wherein L is an integer. 
     
     
         84 . The user equipment according to  claim 82 , wherein the extracting processor extracts the modulation symbols of the candidate E-PDCCH from resource elements occupied by L control channel elements allocated to the candidate E-PDCCH according to an order of subcarriers in each OFDM symbol.