Method and apparatus for relaying data in wireless communication system based on TDD

Abstract

The present invention provides a method and an apparatus of relaying data in a wireless communication system based on Time Division Duplex (TDD). A relay station receives downlink data from a base station in an uplink subframe and relays the downlink data to at least one mobile station. Accordingly, the efficiency of resource allocation for a relay station can be improved.

The invention claimed is: 
     
       1. A method of relaying data in a wireless communication system based on Time Division Duplex (TDD) using a radio frame comprising a plurality of subframes, each of the plurality of subframes comprising at least one or more downlink subframes and at least one or more uplink subframes that are defined between a base station and at least one mobile station, the method performed by a relay station and comprising:
 receiving swapped subframe information informing that a first uplink subframe among only the at least one or more uplink subframes, except for the at least one or more downlink subframes, is to be changed into a downlink subframe, 
 wherein the first uplink subframe was originally designated as an uplink subframe only for the at least one mobile station for transmission to the base station, but is changed by the base station into the downlink subframe to transmit a downlink data to the relay station; 
 receiving, by the relay station and from the base station, the downlink data on first resources of the first uplink subframe, 
 wherein the base station lowers a transmit power on the first uplink subframe thereby reducing an interference, and wherein the first resources used by the base station to transmit the downlink data in the first uplink subframe do not overlap with resources used by the mobile station to transmit an uplink data; and 
 relaying, by the relay station, the downlink data to the at least one mobile station. 
 
     
     
       2. The method of  claim 1 , wherein the resources are subject to time division or frequency division. 
     
     
       3. The method of  claim 1 , wherein the radio frame comprises 10 subframes. 
     
     
       4. The method of  claim 3 , wherein the radio frame corresponds to at least any one of configurations in Table 1 below, wherein ‘D’ denotes a downlink subframe, ‘U’ denotes an uplink subframe, and ‘S’ denotes a special subframe: 
       
         
           
                 
                 
               
                     
                 
                   UPLINK- 
                     
                 
                   DOWN-LINK 
                   SUBFRAME NUMBER 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   CONFIGURATION 
                   0 
                   1 
                   2 
                   3 
                   4 
                   5 
                   6 
                   7 
                   8 
                   9 
                 
                     
                 
                   0 
                   D 
                   S 
                   U 
                   U 
                   U 
                   D 
                   S 
                   U 
                   U 
                   U 
                 
                   1 
                   D 
                   S 
                   U 
                   U 
                   D 
                   D 
                   S 
                   U 
                   U 
                   D 
                 
                   2 
                   D 
                   S 
                   U 
                   D 
                   D 
                   D 
                   S 
                   U 
                   D 
                   D 
                 
                   3 
                   D 
                   S 
                   U 
                   U 
                   U 
                   D 
                   D 
                   D 
                   D 
                   D 
                 
                   4 
                   D 
                   S 
                   U 
                   U 
                   D 
                   D 
                   D 
                   D 
                   D 
                   D 
                 
                   5 
                   D 
                   S 
                   U 
                   D 
                   D 
                   D 
                   D 
                   D 
                   D 
                   D 
                 
                   6 
                   D 
                   S 
                   U 
                   U 
                   U 
                   D 
                   S 
                   U 
                   U 
                    D. 
                 
                     
                 
             
                
                
                
               
            
             
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
       5. A relay station in a wireless communication system based on Time Division Duplex (TDD) using a radio frame comprising a plurality of subframes, the plurality of subframes comprising at least one or more downlink subframes and at least one or more uplink subframes that are defined between a base station and at least one mobile station, the relay station comprising:
 a transceiver configured to transmit or receive a radio signal; and 
 
       a processor coupled to the transceiver and configured to:
 receive swapped subframe information informing that a first uplink subframe among only the at least one or more uplink subframes, except for the at least one or more downlink subframes, is to be changed into a downlink subframe, 
 wherein the first uplink subframe was originally designated as an uplink subframe only for the at least one mobile station for transmission to the base station, but is changed by the base station into the downlink subframe to transmit a downlink data to the relay station; 
 receive, from the base station, the downlink data on first resources of the first uplink subframe, 
 wherein the base station lowers a transmit power on the first uplink subframe thereby reducing an interference, and wherein the first resources used by the base station to transmit the downlink data in the first uplink subframe do not overlap with resources used by the mobile station to transmit an uplink data; and 
 relay the downlink data to the at least one mobile station.