Method and apparatus to provide low cost transmit beamforming for network devices

Abstract

Techniques and structures for use in generating an approximated beamforming matrix in a MIMO based system are disclosed. The techniques and structures may be used to allow closed loop MIMO beamforming to be performed within a device that does not include singular value decomposition (SVD) circuitry.

1 . A method of performing implicit beamforming by a transmitting station in a wireless network, comprising:
 transmitting a first training signal to a receiving station using a current beamforming vector;   receiving a second training signal from the receiving station;   selecting a new beamforming vector as the current beamforming vector based on the received second training signal; and   repeating said transmitting, receiving, and selecting until a condition is met.   
     
     
         2 . The method of  claim 1 , wherein repeating repeats said transmitting, receiving, and selecting at least three times. 
     
     
         3 . The method of  claim 1 , wherein the condition is a termination event. 
     
     
         4 . The method of  claim 3 , wherein the termination event is a termination of exchanging frames. 
     
     
         5 . The method of  claim 1 , further comprising:
 transmitting data using the current beamforming vector subsequent to the condition being met.   
     
     
         6 . A method of performing implicit beamforming by a receiving station in a wireless network, comprising:
 receiving a first training signal from a transmitting station;   computing a current beamforming vector based on the first transmitting signal;   transmitting a second training signal to the transmitting station using the current beamforming vector; and   repeating said receiving, computing, and transmitting until a condition is met.   
     
     
         7 . The method of  claim 6 , wherein repeating repeats said receiving, computing, and transmitting at least three times. 
     
     
         8 . The method of  claim 6 , wherein the condition is a termination event. 
     
     
         9 . The method of  claim 8 , wherein the termination event is a termination of exchanging frames or a termination of calibration. 
     
     
         10 . The method of  claim 6 , further comprising:
 receiving data using the current beamforming vector subsequent to the condition being met.   
     
     
         11 . A method of performing implicit beamforming by a transmitting station in a wireless network, comprising:
 transmitting a first training signal to a receiving station using a transmit beamforming vector;   receiving a second training signal from the receiving station;   selecting a new transmit beamforming vector as based on the received second training signal; and   repeating said transmitting, receiving, and selecting until exchanging frames is terminated or until calibration is terminated.   
     
     
         12 . The method of  claim 11 , wherein repeating repeats said transmitting, receiving, and selecting at least three times. 
     
     
         13 . The method of  claim 11 , further comprising:
 transmitting data using the transmit beamforming vector after the calibration is terminated.