Patent ID: 8478203

Claim:
A method for communications in a wireless network with a predetermined signal bandwidth, having a multipoint-broadcast set comprising a plurality of base stations and a plurality of mobile users, some of said mobile users being phase-feedback mobile users, comprising: (a) sending downlink-pilot signals via a downlink channel from said base stations to said phase-feedback mobile users, (b) generating downlink-channel estimates at said phase-feedback mobile users, (c) sending standard uplink-pilot signals from said mobile users to said base stations, (d) generating uplink-channel estimates at said base stations, (e) transmitting downlink-channel phase information from said phase-feedback mobile users to said base stations, (f) determining carrier-phase differences (CPDs) between said base stations and said phase-feedback mobile users, (g) exchanging said CPDs among said base stations, and (h) determining relative phases between said base stations from said CPDs, whereby said base stations are phase-synchronized when said relative phases have been determined, and said base stations are able to determine the pre-coding matrix for multipoint broadcasting with said uplink-channel estimates and said relative phases.