Multi-site MIMO cooperation in cellular networks

A cellular communications system comprising:

• a first receiver located at a first transmitting site, wherein the first receiver is configured to receive from a target mobile terminal, a first precoder, the first transmitting site comprising a first antenna array;
• a second receiver located at a second transmitting site, wherein the second receiver is configured to receive from the target mobile terminal a second precoder and phase correction feedback based on one or more phase differences of signal frequencies detected by the target mobile terminal, the second transmitting site comprising a second antenna array;
• a first transmitter located at the first transmitting site, wherein the first transmitter is configured to transmit a first data stream to the target mobile terminal using a first beam formed by the first antenna array;
• and
• a second transmitter located at the second transmitting site, wherein the second transmitter is configured to:
• transmit a second data stream to the target mobile terminal using a second beam formed by the second antenna array, and
• perform a phase correction based on the phase correction feedback to result in constructive addition of the first and second beams upon arriving at the target mobile terminal, wherein the phase correction is performed by applying random phase sequences to determine a best phase combination.