Method and system for feedback of antenna beamforming

Abstract

The disclosed systems and methods achieve improved communication by periodically sending sounding packets from a transmitter; feeding back, from a receiver, the change in beamforming estimation according to reception of the sounding packets; and utilizing the change in beamforming estimation to produce transmitter beamforming.

What is claimed is: 
     
         1 . A transmitter within a communication system, comprising:
 a plurality of antennas for:
 transmitting a first plurality of sounding packets to a receiver; 
 transmitting a second plurality of sounding packets to the receiver; and 
 receiving a feedback signal from the receiver, the feedback signal being generated by the receiver based on a difference between a first beamforming estimate determined based on the first plurality of sounding packets and a second beamforming estimate determined based on the second plurality of sounding packets; and 
   a processor for configuring beamforming of the plurality of antennas based on the feedback signal;   wherein the feedback signal includes only a single bit when the first beamforming estimate and the second beamforming estimate are substantially the same;   wherein the feedback signal includes multiple bits when the first beamforming estimate and the second beamforming estimate differ.   
     
     
         2 . The transmitter of  claim 1 , wherein the feedback signal is indicative of the change in one or more parameters between the first beamforming estimate and the second beamforming estimate. 
     
     
         3 . The transmitter of  claim 2 , wherein the first beamforming estimate and the second beamforming estimate are functions of one or more angles of a sounding packet in the first and second plurality of sounding packets and the one or more parameters include the one or more angles. 
     
     
         4 . The transmitter of  claim 1 , wherein the first beamforming estimate and the second beamforming estimate are beamforming estimation matrices. 
     
     
         5 . The transmitter of  claim 1 , wherein the first beamforming estimate is acquired from a first channel estimate matrix based on the first plurality of sounding packets and the second beamforming estimate is acquired from a second channel estimate matrix based on the second plurality of sounding packets. 
     
     
         6 . The transmitter of  claim 1 , wherein the communication system is a Multiple-Input Multiple-Output (MIMO) system, the plurality of antennas includes a plurality of transmit antennas and the receiver further includes a plurality of receive antennas. 
     
     
         7 . The transmitter of  claim 6 , wherein each of the first plurality of sounding packets and the second plurality of sounding packets includes multiple streams of sounding packets transmitted over the plurality of transmit antennas and received over the plurality of receive antennas. 
     
     
         8 . The transmitter of  claim 7 , wherein each of the multiple streams is a periodic transmission of a sequence of known by the receiver. 
     
     
         9 . The transmitter of  claim 7 , wherein each of the first beamforming estimate and the second beamforming estimate are beamforming estimate matrices having a number of rows corresponding to a number of transmit antennas and a number of columns corresponding to a number of streams. 
     
     
         10 . The transmitter of  claim 6 , wherein each of the first beamforming estimate and the second beamforming estimate are beamforming estimate matrices having a number of rows corresponding to a number of receive antennas and a number of columns corresponding to a number of transmit antennas. 
     
     
         11 . The transmitter of  claim 1 , wherein the first plurality of packets are transmitted at a first time and the second plurality of packets are transmitted at a second time subsequent to the first time. 
     
     
         12 . A method for improving communication, wherein the method comprises:
 transmitting a first plurality of sounding packets from a transmitter to a receiver;   transmitting a second plurality of sounding packets from the transmitter to the receiver; and   receiving a feedback signal at the transmitter from the receiver, the feedback signal being generated by the receiver based on a difference between a first beamforming estimate determined based on the first plurality of sounding packets and a second beamforming estimate determined based on the second plurality of sounding packets; and   configuringbeamforming of the transmitter based on the feedback signal;   wherein the feedback signal includes only a single bit when the first beamforming estimate and the second beamforming estimate are substantially the same;   wherein the feedback signal includes multiple bits when the first beamforming estimate and the second beamforming estimate differ.   
     
     
         13 . The method of  claim 12 , wherein the first beamforming estimate and the second beamforming estimate are in the form of a matrix. 
     
     
         14 . The method of  claim 13 , wherein the first beamforming matrix is based on a channel according to the first plurality sounding packets. 
     
     
         15 . The method of  claim 14 , wherein the second beamforming matrix is based on a channel according to the second plurality sounding packets. 
     
     
         16 . The method of  claim 12 , wherein the feedback signal is based on a difference between one or more angles in the first beamforming estimate and one or more angles in the second beamforming estimate. 
     
     
         17 . The method of  claim 12 , wherein the communication system is a Multiple-Input Multiple-Output (MIMO) system, the transmitter includes a plurality of transmit antennas and the receiver includes a plurality of receive antennas. 
     
     
         18 . The method of  claim 17 , wherein each of the first plurality of sounding packets and the second plurality of sounding packets includes multiple streams of sounding packets transmitted over the plurality of transmit antennas and received over the plurality of receive antennas. 
     
     
         19 . The method of  claim 12 , wherein the first plurality of packets are transmitted at a first time and the second plurality of packets are transmitted at a second time subsequent to the first time. 
     
     
         20 . A transmitter within a communication system, comprising:
 a plurality of antennas for:
 transmitting a first plurality of sounding packets to a receiver; 
 transmitting a second plurality of sounding packets to the receiver; and 
 receiving a respective feedback signal from the receiver, the feedback signal being generated by the receiver based on a difference between a first beamforming estimate determined based on the first plurality of sounding packets and a second beamforming estimate determined based on the second plurality of sounding packets; and 
   a processor for configuring beamforming of the plurality of antennas based on the feedback signal;   wherein the feedback signal is based on a difference between one or more angles in the first beamforming estimate and one or more angles in the second beamforming estimate;   wherein the feedback signal includes only a single bit when the first beamforming estimate and the second beamforming estimate are substantially the same;   wherein the feedback signal includes multiple bits when the first beamforming estimate and the second beamforming estimate differ.