Method of transmitting data using constellation rearrangement

Abstract

A data retransmission method using hybrid automatic repeat request (HARQ) includes transmitting a data block, receiving a retransmission request signal for the data block, generating a retransmission block by performing swapping or inversion between bits constituting the data block according to the retransmission request signal, and transmitting the retransmission block.

1 . A data retransmission method using hybrid automatic repeat request (HARQ), comprising:
 transmitting a data block;   receiving a retransmission request signal for the data block;   generating a retransmission block by performing swapping or inversion between bits constituting the data block according to the retransmission request signal; and   transmitting the retransmission block.   
   
   
       2 . The method of  claim 1 , wherein the swapping between bits is performed by swapping a bit having a high bit reliability and a bit having a low bit reliability in previous transmission. 
   
   
       3 . The method of  claim 1 , wherein the data block is a transmission block having a matrix format and consisting of rows whose number is equal to the number of transmit antennas, each row of the transmission block is transmitted through one transmit antenna, bits constituting one row represent bits of one data symbol, and the data symbol is modulated using at least two modulation schemes. 
   
   
       4 . The method of  claim 3 , wherein the swapping between bits is performed by cyclically shifting bits constituting each column of the transmission block, and each column has a different cyclic shift amount. 
   
   
       5 . The method of  claim 1 , wherein the retransmission block is mapped according to the number of retransmissions when using a 16-ary quadrature amplitude modulation (QAM) or 64-QAM scheme as expressed in the following table: 
     
       
         
               
               
               
               
             
                   
               
                 # of trans. 
                 Mapping set 
                 # of trans. 
                 Mapping set 
               
                   
               
                 0 
                 i 1 q 1 i 2 q 2   
                 0 
                 i 1 q 1 i 2 q 2 i 3 q 3   
               
                 1 
                 i 2 q 2 i 1 q 1   
                 1 
                 i 3 q 3 ī 2   q   2 i 1 q 1   
               
                 2 
                 i 1 q 1 ī 2   q   2   
                 2 
                 i 2 q 2 ī 3 q 3 i 1 q 1   
               
                 3 
                 i 2 q 2 ī 1   q   1   
                 3 
                 i 1 q 1 ī 2 q 2 i 3 q 3   
               
               
               
             
                 (a) 16 QAM 
                 (b) 64 QAM 
               
                   
               
           
              
              
              
             
             
              
              
              
              
             
          
           
              
              
             
          
         
       
       where, in i a  and q a  of the table, ‘a’ denotes an index indicating coordinates on a constellation. 
     
   
   
       6 . The method of  claim 1 , wherein the retransmission block is mapped according to the number of retransmissions when using a 16-QAM or 64-QAM scheme as expressed in the following table: 
     
       
         
               
               
               
               
             
                   
               
                 # of re- 
                   
                 # of re- 
                   
               
                 transmission 
                 Optimal mapping 
                 transmission 
                 Optimal mapping 
               
                   
               
                 0 
                 i 1,1 q 1,1 i 1,2 q 1,2   
                 0 
                 i 1,1 q 1,1 i 1,2 q 1,2 i 1,3 q 1,3   
               
                   
                 i 2,1 q 2,1 i 2,2 q 2,2   
                   
                 i 2,1 q 2,1 i 2,2 q 2,2 i 2,3 q 2,3   
               
                 1 
                 i 1,2 q 1,2 i 2,1 q 2,1   
                 1 
                 i 2,3 q 1,3 ī 2,2   q   1,2 i 2,1 q 1,1   
               
                   
                 i 2,2 q 2,2 i 1,1 q 1,1   
                   
                 i 1,3 q 2,3 ī 1,2   q   2,2 i 1,1 q 2,1   
               
                 2 
                 i 1,1 q 1,1 ī 2,2   q   2,2   
                 2 
                 i 2,2 q 2,2 ī 2,3   q   2,3 i 2,1 q 1,1   
               
                   
                 i 2,1 q 2,1 ī 1,2   q   1,2   
                   
                 i 1,2 q 1,2 ī 1,3   q   1,3 i 1,1 q 2,1   
               
                 3 
                 i 1,2 q 1,2 ī 2,1   q   2,1   
                 3 
                 i 2,1 q 1,1 ī 2,2   q   1,2 i 2,3 q 1,3   
               
                   
                 i 2,2 q 2,2 ī 1,1   q   1,1   
                   
                 i 1,1 q 2,1 ī 1,2   q   2,2 i 1,3 q 2,3   
               
               
               
             
                 (a) 16-QAM 
                 (b) 64-QAM 
               
                   
               
           
              
              
              
              
             
             
              
              
              
              
              
              
              
              
             
          
           
              
              
             
          
         
       
       where, in i a,b  and q a,b  of the table, ‘a’ denotes an antenna index and ‘b’ denotes an index indicating coordinates on a constellation. 
     
   
   
       7 . A data retransmission method in a multiple-antenna system, comprising:
 transmitting a first data symbol modulated with a first modulation scheme through a first transmit antenna and transmitting a second data symbol modulated with a second modulation scheme through a second transmit antenna;   generating a new first data symbol and a new second data symbol by performing swapping or inversion on bits constituting the first data symbol and bits constituting the second data symbol; and   transmitting the new first data symbol through the first transmit antenna and transmitting the new second data symbol through the second transmit antenna.   
   
   
       8 . The method of  claim 7 , further comprising receiving a retransmission request signal for the first data symbol and the second data symbol. 
   
   
       9 . An apparatus for wireless communication, comprising:
 a radio frequency (RF) unit for transmitting and receiving a radio signal; and   a processor coupled with the RF unit, for performing HARQ-increment redundancy (IR), and configured to:   sequentially configure data blocks in a cyclic buffer of the HARQ-IR according to a retransmission request, and   transmit the data blocks, wherein if all or some parts of the data block are wrapped around with a previously transmitted data block, constellation rearrangement is performed on the wraparound parts.   
   
   
       10 . The apparatus of  claim 9 , wherein the processor is configured to use 16-QAM as a modulation scheme, and perform constellation rearrangement according to the number of wraparounds as described in the following table: 
     
       
         
               
               
             
                   
               
                 # of wraparound 
                 Mapping rule 
               
                   
               
                 0 
                 i 1  q 1  i 2  q 2   
               
                 1 
                 i 2  q 2  i 1  q 1   
               
                 2 
                 i 1  q 1  ī 2    q   2   
               
                 3 
                 i 2  q 2  ī 1    q   1   
               
                   
               
           
              
              
              
             
             
              
              
              
              
              
             
          
         
       
       where, in i a  and q a  of the table, ‘a’ denotes an index indicating coordinates on a constellation. 
     
   
   
       11 . The apparatus of  claim 9 , wherein the processor is configured to use 16-QAM as a modulation scheme, and perform constellation rearrangement according to the number of wraparounds as described in the following table: 
     
       
         
               
               
             
                   
               
                 # of wraparound 
                 Mapping rule 
               
                   
               
                 0 
                 i 1,1 q 1,1 i 1,2 q 1,2   
               
                   
                 i 2,1 q 2,1 i 2,2 q 2,2   
               
                 1 
                 i 1,2 q 1,2 i 2,1 q 2,1   
               
                   
                 i 2,2 q 2,2 i 1,1 q 1,1   
               
                 2 
                 i 1,1 q 1,1 ī 2,2   q   2,2   
               
                   
                 i 2,1 q 2,1 ī 1,2   q   1,2   
               
                 3 
                 i 1,2 q 1,2 ī 2,1   q   2,1   
               
                   
                 i 2,2 q 2,2 ī 1,1   q   1,1   
               
                   
               
           
              
              
              
             
             
              
              
              
              
              
              
              
              
              
             
          
         
       
       where, in i a,b  and q a,b  of the table, ‘a’ denotes an antenna index and ‘b’ denotes an index indicating coordinates on a constellation. 
     
   
   
       12 . The apparatus of  claim 9 , wherein the processor is configured to use 64-QAM as a modulation scheme, and perform constellation rearrangement according to the number of wraparounds as described in the following table: 
     
       
         
               
               
             
                   
               
                 # of wraparound 
                 Mapping rule 
               
                   
               
                 0 
                 i 1 q 1 i 2 q 2 i 3 q 3   
               
                 1 
                 i 3 q 3 ī 2   q   2 i 1 q 1   
               
                 2 
                 i 2 q 2 ī 3   q   3 i 1 q 1   
               
                 3 
                 i 1 q 1 ī 2   q   2 i 3 q 3   
               
                   
               
           
              
              
              
             
             
              
              
              
              
              
             
          
         
       
       where, in ia and qa of the table, ‘a’ denotes an index indicating coordinates on a constellation. 
     
   
   
       13 . The apparatus of  claim 9 , wherein the processor is configured to use 64-QAM as a modulation scheme, and perform constellation rearrangement according to the number of wraparounds as described in the following table: 
     
       
         
               
               
             
                   
               
                 # of wraparound 
                 Mapping rule 
               
                   
               
                 0 
                 i 1,1 q 1,1 i 1,2 q 1,2 i 1,3 q 1,3   
               
                   
                 i 2,1 q 2,1 i 2,2 q 2,2 i 2,3 q 2,3   
               
                 1 
                 i 2,3 q 1,3 ī 2,2   q   1,2 i 2,1 q 1,1   
               
                   
                 i 1,3 q 2,3 ī 1,2   q   2,2 i 1,1 q 2,1   
               
                 2 
                 i 2,2 q 2,2 ī 2,3   q   2,3 i 2,1 q 1,1   
               
                   
                 i 1,2 q 1,2 ī 1,3   q   1,3 i 1,1 q 2,1   
               
                 3 
                 i 2,1 q 1,1 ī 2,2   q   1,2 i 2,3 q 1,3   
               
                   
                 i 1,1 q 2,1 ī 1,2   q   2,2 i 1,3 q 2,3   
               
                   
               
           
              
              
              
             
             
              
              
              
              
              
              
              
              
              
             
          
         
       
       where, in i a,b  and q a,b  of the table, ‘a’ denotes an antenna index and ‘b’ denotes an index indicating coordinates on a constellation.