Patent ID: 8223873

Claim:
A method of obtaining a source beamforming vector and a destination beamforming vector for transmission and reception of a data signal over a wireless communications channel, the method comprising: i) modulating, at a first station, a first training sequence with a first source beamforming vector, wherein the first training sequence has a first spreading gain; ii) transmitting, at the first station, the modulated first training sequence to a second station; iii) receiving, at the second station, the modulated first training sequence; iv) obtaining, at the second station, a first destination beamforming vector based on the received first training sequence; v) modulating, at the second station, a second training sequence with the first destination beamforming vector, wherein the second training sequence has a second spreading gain; vi) transmitting, at the second station, the modulated second training sequence to the first station; vii) receiving, at the first station, the modulated second training sequence; viii) obtaining, at the first station, a second source beamforming vector based on the received second training sequence; ix) modulating, at the first station, a third training sequence with the second source beamforming vector, wherein the third training sequence has a third spreading gain different from the first spreading gain; x) transmitting, at the first station, the modulated third training sequence to the second station; xi) receiving, at the second station, the modulated third training sequence; xii) obtaining, at the second station, a second destination beamforming vector based on the received third training sequence; xiii) modulating, at the second station, a fourth training sequence with the second destination beamforming vector, wherein the fourth training sequence has a fourth spreading gain different from the second spreading gain; xiv) transmitting, at the second station, the fourth training sequence to the first station; xv) receiving, at the first station, the modulated fourth training sequence; xvi) obtaining, at the first station, a third source beamforming vector based on the received fourth training sequence; and xvii) determining, at the first station, whether to use the third source beamforming vector to modulate a data signal to be transmitted to the second station, wherein ix)-xvii) are repeated until it is determined to use the most recently obtained source beamforming vector to modulate a data signal to be transmitted to the second station and to use the most recently obtained destination beamforming vector to demodulate the data signal.