Title: Reduced complexity per-survivor iterative timing recovery using max-log-MAP algorithm

Authors: Chuan Hsian Pu; Ezra Morris Abraham Gnanamuthu; Fook Loong Lo; Mau-Luen Tham

Addresses: Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long Cheras 43000, Kajang, Selangor, Malaysia ' Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long Cheras 43000, Kajang, Selangor, Malaysia ' Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long Cheras 43000, Kajang, Selangor, Malaysia ' Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long Cheras 43000, Kajang, Selangor, Malaysia

Abstract: In this paper, we propose a reduced complexity (RC) per-survivor-processing (RC-PSP) iterative timing recovery scheme. The objective is to lessen the computational burden while approaching the optimal system performance of the existing full-complexity (FC) log-MAP (FC-PSP) iterative recovery scheme. This is achieved by utilising the max-log-MAP framework, which converts the multiplications and additions to maximum operations. According to Spasov, Gushev and Ristov, such framework consumes less power, reduces space on a chip and increases decoding speed. Robertson et al. showed that max-log-MAP PSP requires only 5 × 2^M − 2 max operations, 10 × 2^M additions and 8 multiplications by ±1. Furthermore, it offers a direct mathematical framework for converting the log-MAP-based PSP to max-log-MAP-based PSP for timing recovery. The simulations show that the proposed method outperforms the previous methods. The computational complexity for the max-log-MAP PSP is significantly reduced at the cost of a small bit error rate (BER) performance loss.

Keywords: max-Log-MAP; maximum-a-posteriori; MAP; signal-to-noise ratio; SNR; timing error detector; TED; turbo-codes; trellis; timing recovery; per-survivor processing; PSP; bit error rate; BER; low-density parity-check; LDPC.

DOI: 10.1504/IJICT.2020.108964

International Journal of Information and Communication Technology, 2020 Vol.17 No.2, pp.146 - 163

Received: 19 Nov 2018
Accepted: 19 Jul 2019
Published online: 11 Aug 2020 *

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