Method for transmitting reference signal for terminal demodulation in radio mobile communication system, and apparatus for implementing the same

Abstract

The present invention relates to a method for transmitting a data demodulation reference signal in a radio mobile communication system. The method comprises: a step for generating a sub-frame including the data demodulation reference signal, and a step for transmitting the generated sub-frame. The 1st and 2nd demodulation reference signal pattern groups include plural demodulation signal patterns orthogonal to each other, and are differentiated from each other with regard to time-frequency resources. In the data demodulation reference signal, demodulation reference signal patterns which are respectively orthogonal to each other M (M≦N) and N-M times are respectively included in the 1st and 2nd demodulation reference signal pattern groups if the rank is N.

The invention claimed is: 
     
       1. A method for transmitting demodulation reference signals in a radio mobile communication system, the method comprising:
 mapping, by a base station, the demodulation reference signals for multiple antenna ports to a resource block according to mapping patterns; and 
 transmitting, by the base station to a user equipment, the demodulation reference signals in a downlink subframe, 
 wherein:
 the mapping patterns are classified as a first pattern group and a second pattern group, 
 the first pattern group corresponds to at least one antenna port among the multiple antenna ports, 
 the second pattern group corresponds to remaining at least one antenna port among the multiple antenna ports, 
 resource element positions of the first pattern group are shifted by 1 subcarrier compared to resource element positions of the second pattern group, and 
 the first pattern group and the second pattern group are defined in a same resource block, and 
 
 wherein:
 the first pattern group includes 12 resource element positions in the resource block, and 
 the second pattern group includes another 12 resource element positions in the resource block. 
 
 
     
     
       2. The method according to  claim 1 , wherein:
 the resource element positions of the first pattern group are commonly used for the at least one antenna port among the multiple antenna ports; and 
 the resource element positions of the second pattern group are commonly used for the remaining at least one antenna port among the multiple antenna ports. 
 
     
     
       3. The method according to  claim 1 , wherein:
 the demodulation reference signals of the at least one antenna ports corresponding to the first pattern group are multiplexed using a first set of orthogonal code sequences; and 
 the demodulation reference signals of the remaining at least one antenna ports corresponding to the second pattern group are multiplexed using a second set of orthogonal code sequences. 
 
     
     
       4. The method according to  claim 1 , wherein:
 the resource element positions of the first pattern group are on 4 orthogonal frequency division multiplexing symbols in the downlink subframe; and 
 the resource element positions of the second pattern group are on the 4 orthogonal frequency division multiplexing symbols in the downlink subframe. 
 
     
     
       5. The method according to  claim 1 , wherein the resource block includes 14 orthogonal frequency division multiplexing symbols and 12 subcarriers. 
     
     
       6. The method according to  claim 1 , wherein the demodulation reference signals are used by the user equipment to demodulate downlink data. 
     
     
       7. The method according to  claim 1 , wherein a number of the multiple antenna ports is  3 ,  4 ,  5 ,  6 ,  7 , or  8 . 
     
     
       8. A base station for transmitting demodulation reference signals in a radio mobile communication system, the base station comprising:
 a transmitter; 
 a receiver; and 
 a processor is configured to:
 map the demodulation reference signals for multiple antenna ports to a resource block according to mapping patterns; and 
 transmit, to a user equipment using the transmitter, the demodulation reference signals in a downlink subframe, 
 
 wherein:
 the mapping patterns are classified as a first pattern group and a second pattern group, 
 the first pattern group corresponds to at least one antenna port among the multiple antenna ports, 
 the second pattern group corresponds to remaining at least one antenna port among the multiple antenna ports, 
 resource element positions of the first pattern group are shifted by 1 subcarrier compared to resource element positions of the second pattern group, and 
 the first pattern group and the second pattern group are defined in a same resource block, and 
 wherein: 
 the first pattern group includes 12 resource element positions in the resource block, and 
 the second pattern group includes another 12 resource element positions in the resource block. 
 
 
     
     
       9. The base station according to  claim 8 , wherein:
 the resource element positions of the first pattern group are commonly used for the at least one antenna port among the multiple antenna ports; and 
 the resource element positions of the second pattern group are commonly used for the remaining at least one antenna port among the multiple antenna ports. 
 
     
     
       10. The base station according to  claim 8 , wherein:
 the demodulation reference signals of the at least one antenna ports corresponding to the first pattern group are multiplexed using a first set of orthogonal code sequences; and 
 the demodulation reference signals of the remaining at least one antenna ports corresponding to the second pattern group are multiplexed using a second set of orthogonal code sequences. 
 
     
     
       11. The base station according to  claim 8 , wherein:
 the resource element positions of the first pattern group are on 4 orthogonal frequency division multiplexing symbols in the downlink subframe; and 
 the resource element positions of the second pattern group are on the 4 orthogonal frequency division multiplexing symbols in the downlink subframe. 
 
     
     
       12. The base station according to  claim 8 , wherein the resource block includes:
 14 orthogonal frequency division multiplexing symbols; and 
 12 subcarriers. 
 
     
     
       13. The base station according to  claim 8 , wherein the demodulation reference signals are used by the user equipment to demodulate downlink data. 
     
     
       14. The base station according to  claim 8 , wherein a number of the multiple antenna ports is  3 ,  4 ,  5 ,  6 ,  7 , or  8 .