Simplified Soft-output Demapper Based on a Linear Transformation Technique for M-ary PSK

• Main Authors: Jianping Li, Yameng Shi
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2014-10-01
• Series: Sensors & Transducers
• Subjects: Soft demapper; Phase-shift keying (PSK); Bit metric; Bit-interleaved coded modulation (BICM); Computation complexity.
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/october_2014/Vol_181/P_2489.pdf

Combining channel coding with high-order modulation schemes, namely coded modulation (CM), is an efficient digital transmission technology. CM requires the demapper to provide a soft decision bit metric as a part of the inputs to the decoder. This paper proposes an efficient soft- output demapper for M-ary PSK. This novel demodulation algorithm continues to evolve the conventional MAX-Log-MAP algorithm and summarizes the final derivation into a form of matrix multiplication. The Computational complexity for getting one bit soft value of a signal by employing the proposed algorithm remains a constant with the increase of modulation order. Meanwhile, the theoretical analysis and simulation results prove that the novel simplified soft-output demapper can obtain the same performance as MAX-Log-MAP.