Patent ID: 8902834

Claim:
A method for use in a wideband multiple-input multiple-output (MIMO) wireless communication system in which: a plurality of adjacent cells are provided each containing one or more base stations operable to transmit signals to, and receive signals transmitted from, one or more users, a user is operable to feed back to the relevant base station(s) channel state information relating to channel(s) between the relevant base station(s) and that user; and base stations are operable to adapt signals for transmission to users, based on the fed back channel state information, to account for channel variations; the method comprising: defining a parameter related to time variation in channel spatial structure that indicates the extent of the change in time of a correlation matrix distance of spatial correlation matrices, the spatial correlation matrices being based on an averaged channel correlation matrix over a bandwidth of the wideband MIMO wireless communication system; obtaining information related to time-variation in channel spatial structure by determining a value of the parameter; and adjusting the timing with which a user feeds back channel state information, based on the time variation in channel spatial structure.