Self-recovering receivers for direct-sequence spreadspectrum signals with unknown spreading codes are discussed in this paper. Applications include signal interception, jamming, and low probability of intercept (LPI) communications. A multirate/multichannel, discrete-time model of the spread spectrum signal is introduced, which establishes links with array processing techniques. Borrowing blind channel estimation ideas, which were originally developed in the context of fractionally spaced equalizers or receivers with multiple antennas, linear solutions are obtained that are independent of the input distribution. The signal interception problem is further studied, and a zero-forcing (ZF) receiver/equalizer is proposed to recover the transmitted data. Its performance is analyzed, and some illustrative simulations are presented.
Bibliographical noteFunding Information:
Manuscript received July 5, 1995; revised December 27, 1996. This work was supported by the National Science Foundation under Grant NSF-MIP 9424305. The associate editor coordinating the review of this paper and approving it for publication was Prof. Michael D. Zoltowski.