×

Use of Walsh-Hadamard transform for forward link multiuser detection in CDMA systems

  • US 6,798,737 B1
  • Filed: 10/06/1999
  • Issued: 09/28/2004
  • Est. Priority Date: 10/06/1999
  • Status: Expired due to Term
First Claim
Patent Images

1. A station capable of receiving information containing Walsh coding for a plurality of channels and canceling interference from the received information comprising:

  • (a) a memory for storing received signals containing a Walsh code for each of a plurality of channels as well as reflected and/or refracted versions of said received signals;

    (b) a first plurality of signal paths selectively coupled to said memory, each said signal path coupled to said memory for receiving said signals stored in said memory, each said signal path including;

    (i) a first delay circuit corresponding to a different one of a plurality of time spaced apart conditions of said received signal;

    (ii) an inverse fast Walsh transform circuit coupled to said delay circuit for removing the Walsh code corresponding to that path from said received signal;

    (iii) estimation circuitry for providing an estimate for each path of phase shift and attenuation of said received signal in that path, said estimation circuitry coupled to said first delay circuit;

    (iv) multiplication circuitry for multiplying the conjugate of said estimate with said signal after removal of said Walsh code in each said path to provide a path output for each said channel, said multiplication circuitry coupled to said transform circuit; and

    (v) a combiner coupled to said multiplication circuitry for combining the path outputs of each of said channels to provide a data estimate.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×