A self-orthogonal code and its maximum-likelihood decoder for combined channel estimation and error protection

Recent researches have confirmed that better system performance can be obtained by jointly considering channel equalization and channel estimation in the code design, when compared with the system with individually optimized devices. However, the existing codes are mostly searched by computers, and hence, exhibit no good structure for efficient decoding. In this paper, a systematic construction for the codes for combined channel estimation and error protection is proposed. Simulations show that it can yield codes of comparable performance to the computer-searched best codes. In addition, the structural codes can now be maximum-likelihoodly decodable in terms of a newly derived recursive metric for use of the priority-first search decoding algorithm. Thus, the decoding complexity reduces considerably when compared with that of the exhaustive decoder. In light of the rule-based construction, the feasible codeword length that was previously limited by the capability of code-search computers can now be further extended, and therefore facilitates their applications.