Patent ID: 8111709

Claim:
A wireless communication method in a MIMO system having a first cell and one or more second cells adjacent to each other, each cell served by a base station and having a plurality of fixed or mobile subscriber stations, the base station having a transmission link to each subscriber station in the cell on a respective MIMO channel, the method comprising: in the base station of the first cell: receiving, from a second cell, a request for reduction of interference to a subscriber station in the second cell caused by transmissions from the base station of the first cell; identifying a rank deficient MIMO channel among the transmission links from the base station to each subscriber station in the first cell, checks a correlation between a most rank deficient MIMO channel and a MIMO channel to said subscriber station in the second cell, and selects the most rank deficient MIMO channel unless the correlation exceeds a threshold which, instead selects the next most rank deficient MIMO channel to be made the subject of precoding; and applying precoding to transmissions on the selected MIMO channel to reduce interference experienced by said subscriber station in the second cell.