Method, apparatus and system for phase difference adjustment in transmit diversity

1. A method of selecting a value of a transmit diversity parameter by a mobile device having a first and a second antenna comprising:

transmitting a first signal concurrently on said first and second antennas, wherein transmissions of said first signal from said first and second antennas differ by a first value of a transmit diversity parameter;

transmitting an indication that said first signal is transmitted on said first antenna;

transmitting a second signal concurrently on said first and second antennas, wherein transmissions of said second signal from said first and second antennas differ by a second value of said transmit diversity parameter;

transmitting an indication that said second signal is transmitted on said second antenna;

receiving an antenna selection signal from a second communication device indicating a preference between said first signal and said second signal; and

selecting a value of the transmit diversity parameter based on the indicated preference between said first signal and said second signal.

2. The method of claim 1 , wherein said transmit diversity parameter is a phase difference between said first and second antennas.

3. The method of claim 1 , wherein said transmit diversity parameter is a power ratio between said first and second antennas.

4. A mobile device comprising:

first and second antennas;

a transmit diversity adjustment module to receive a transmit diversity parameter value and send to a first and a second antenna signals differing by said value of the transmit diversity parameter; and

a processor to control the value of said transmit diversity parameter, wherein said processor is to:

cause to be transmitted a first signal concurrently on said first and second antennas, wherein transmissions of said first signal from said first and second antennas differ by a first value of a transmit diversity parameter;

cause to be transmitted an indication that said first signal is transmitted on said first antenna;

cause to be transmitted a second signal concurrently on said first and second antennas, wherein transmissions of said second signal from said first and second antennas differ by a second value of said transmit diversity parameter;

cause to be transmitted an indication that said second signal is transmitted on said second antenna;

receive an antenna selection signal from a second communication device indicating a preference between said first signal and said second signal; and

select a value of the transmit diversity parameter based on the indicated preference between said first signal and said second signal.

5. The mobile device of claim 4 , wherein said transmit diversity parameter is a phase difference between said first and second antennas.

6. The mobile device of claim 4 , wherein said transmit diversity parameter is a power ratio between said first and second antennas.