Protocol to support adaptive station-dependent channel state information feedback rate in multi-user communication systems

Methods and apparatuses are proposed for supporting one or more user-dependent channel state information (CSI) feedback rates in a downlink spatial division multiple access (SDMA) system. For certain aspects, an access point (AP) may receive a channel evolution feedback from one or more stations and send a request for CSI to the stations whose CSI values need to be updated. For certain aspects, the AP may poll the stations for updated CSI values. For certain aspects, deterministic back-off timers may be assigned to the stations indicating when to send their CSI feedback. The proposed methods may improve system performance.