Method and system of operating a multi-user system

Abstract

A method and system is disclosed for grouping the multiple stations connected to an access point (AP). The system and method comprise sending a sounding packet to a plurality of stations, wherein the stations may be all or part of the stations that are located within the range of the AP. The stations that receive the sounding packets respond to the AP, and the AP determines the channel state information (CSI) from the responses. According to the CSI, the AP divides the multiple stations into several groups. According to an embodiment of the present invention, a confirmation step is performed to each group of stations, respectively. The AP sends a second sounding packet to each group of stations, and verifies the CSI between each station group by group. Therefore, the method and system provides for monitoring the validation of each group by periodically sending sounding packets to each group.

We claim: 
     
         1 . A method for a transmitter in a multi-user system, comprising:
 sending a non-precoded sounding request to a plurality of receivers, wherein the transmitter gathers channel state information from each receiver and divides the plurality of receivers into at least one group;   sending a precoded sounding request to the at least one group; and   receiving signal to interference and noise ratio (SINR) information measured at the plurality of receivers.   
     
     
         2 . The method of  claim 1 , further comprising,
 sending an initial sounding to the plurality of receivers before the step of sending the non-precoded sounding request; and   gathering channel state information from the plurality of receivers.   
     
     
         3 . The method of  claim 2 , wherein the initial sounding is a null data packet. 
     
     
         4 . The method of  claim 1 , wherein the non-precoded sounding request is a null data packet. 
     
     
         5 . The method of  claim 1 , further comprising,
 sending a multi-user packet to the at least one group of receivers; and   measuring SINR information by the at least one group of receivers after receiving the multi-user packet.