Two-bit adaptive LMS-like filtering

The conventional LMS family of adaptive algorithms fail to converge if translated to short-word-length (single-bit, two-bit, or ternary) domains. As such the distinctive advantage of short-word-length systems, namely, the hardware implementation simplicity, has not been put into effect. We propose a 2-bit-domain LMS adaptive filtering structure for noise cancelling where all input, output, and filter coefficients are in 2-bit format. Simulation results showed that the proposed adaptive structure exhibits performance that is equivalent to the infinite-precision LMS algorithm.