Patent ID: 8767862

Claim:
A multiple inputs multiple outputs (MIMO) receiving system having number N channels, comprising: a radio distributed network (RDN) having number N beamformers, each having number K i receive antennas, wherein N is an integer greater than 1 and each K i is an integer greater than 1 for 1≦i≦N; and a phase shifter coupled to each one of the K i receive antennas in each one of the N beamformers, wherein the MIMO receiving system is configured to: (a) determine a phase for each one of said phase shifters that optimizes performance of said MIMO receiving system when receiving a plurality of transmit streams from a plurality of transmit antennas, wherein the optimization is achieved by channel estimation of each one of the transmit streams as seen by each one of the receive antennas, and (b) select a phase for each receive antenna that maximizes a total received power from all transmit streams reaching said receive antenna, wherein the total received power is calculated based on the channel estimation, wherein phase optimization is carried out by: adjusting the antennas one by one recursively, wherein, φ 1 is set to zero, and only contributions from h 1,j,k and h 2,j,k are used to calculate φ 2 ; defining a combined channel S 2,j,k and a channel power p 2,j,k for the first two antennas as: p 2,j,k =[abs(S 2,j,k )] 2 , j=1, 2 . . . M, k=1, 2 . . . L; and choosing φ 2 εS that maximizes − ∑ j = 1 M ⁢ ⁢ ∑ k = 1 L ⁢ ⁢ p 2 , j , k .