Joint maximal ratio combining using time-domauin based signal processing

Abstract

A communication device transmits and receives communication signals with another communication device via a plurality of antennas, a plurality of transmit tapped delay-line filters, a plurality of receive tapped delay-line filters, a combiner/analyzer with a plurality of filters for signal processing; and a plurality of computation blocks. The computation blocks determine complex weights for the tapped delay-line filters for optimizing the received signal-to-noise ratio and the range of communication of the communication device.

1 . A communication device, comprising:
 a plurality of transmit tapped delay-line filters, each associated with a corresponding one of a plurality of antennas;   a plurality of receive tapped delay-line filters, each associated with a corresponding one of the plurality of antennas;   a combiner/analyzer with a plurality of filters for signal processing; and   a plurality of computation blocks that:
 generate a transmit filter vector for processing a signal to be transmitted to another communication device, the transmit filter vector comprised of a plurality of transmit filter sub-vectors defining one or more complex weights associated with the transmit tapped-delay line filter, each transmit filter sub-vector associated with a corresponding one of the plurality of antennas and having a length corresponding to the number taps of the associated transmit tapped-delay line filter; 
 apply the transmit filter vector to a signal to be transmitted from the other communication device; 
 generate a receive filter matrix from a signal received by the plurality of antennas from the other communication device, the receive filter matrix comprised of a plurality of sub-matrices each being a convolution matrix derived from a receive filter sub-vector, wherein each receive filter sub-vector defines one or more complex weights associated with the receive tapped-delay line filter for a corresponding one of each of the plurality of antennas; 
 compute a principal eigenvector of a product of the receive filter matrix and a Hermitian of the receive filter matrix, the principal eigenvector comprised of a plurality of sub-vectors each having a length corresponding to the number of taps of the transmit tapped-delay line filter; and 
 update from the plurality of sub-vectors of the principal eigenvector the plurality of transmit filter sub-vectors. 
   
   
   
       2 . The communication device of  claim 1 , wherein the computation blocks update the plurality of transmit sub-vectors by equating each transmit filter sub-vector to the corresponding sub-vector of the principal eigenvector. 
   
   
       3 . The communication device of  claim 1 , wherein the computation blocks update the plurality of transmit sub-vectors by computing the norm of each of a plurality of sub-vectors of the principal eigenvector and dividing each sub-vector of the principal eigenvector by the norm and by the square root of the number of the plurality of antennas so that the power of the signal transmitted is divided equally among the plurality of antennas. 
   
   
       4 . The communication device of  claim 1 , further comprising:
 a plurality of antennas;   a transmitter coupled to the plurality of antennas and to the combiner/equalizer to upconvert transmit signals generated by the combiner/equalizer for transmission via respective ones of the plurality of antennas; and,   a receiver coupled to the plurality of antennas and to the combiner/equalizer to downconvert signals received by the plurality of antennas and produce receive signals that are coupled to the combiner/equalizer.   
   
   
       5 . The communication device of  claim 1 , wherein the combiner/equalizer is a decision feedback equalizer comprising feedforward filters, a decision block, and a feedback filter. 
   
   
       6 . The communication device of  claim 1 , wherein the combiner/equalizer comprises a maximum likelihood sequence estimator used for maximum likelihood sequence estimator signal processing. 
   
   
       7 . The communication device of  claim 1 , wherein the combiner/equalizer comprises a correlator used for direct sequence spread spectrum signal processing.