Direct blind equalizers of multiple FIR channels: A deterministic approach

Blind equalization of single-input multi-output channels has practical valu e for inverse problems encountered in communications, sonar, and seismic da ta processing. Relying on diversity (sufficient number of multiple outputs) , we bypass the channel estimation step and derive direct blind FIR equaliz ers of co-prime FIR channels. There are no constraints on the inaccessible input, apart from a minimum persistence of elicitation condition; the input can be deterministic or random with unknown color or distribution. At mode rate SNR (>20 dB), the resulting algorithms remain operational even with ve ry short data records (<100 samples), which makes them valuable for equaliz ation of rapidly fading multipath channels. Complexity, persistence of exci tation order, and mean-square error performance tradeoffs are delineated fo r equalizers of single-shift (semi-blind). pair, or, multiple shifts estima ted separately or simultaneously. Optimum and suboptimum combinations of th e equalizers' outputs are also studied. Simulations illustrate the proposed algorithms and compare them with dual deterministic channel identification algorithms.