Single‐channel blind source separation for paired carrier multiple access signals

Abstract

Paired carrier multiple access (PCMA) is one of the most common single‐channel mixtures. It is still a great challenge to recover the transmitted bits from non‐cooperative received PCMA signals, due to the high complexity of existing single‐channel blind source separation (SCBSS) algorithms. Hence, a double‐direction delayed‐decision‐feedback sequence estimation (DD‐DDFSE) algorithm for non‐causal high‐order channel is proposed to realise the separation of PCMA signals. The proposed algorithm employs the Viterbi algorithm (VA) with low‐order channel twice instead of conventional VA with high‐order channel once. The symbols estimated by the initial VA are utilised to equalise the causal and non‐causal taps of the channel beyond the trellis state in the second VA. The relationship between the decision‐feedback error from the initial VA and the performance of the second VA is also derived. Compared with state‐of‐the‐art maximum likelihood sequence estimation algorithms, DD‐DDFSE algorithm can not only decrease the computation complexity but also improve the separation performance.