Quasi-maximum-likelihood multiple-symbol differential detection for time-varying Rayleigh fading channel

• Published in: Electronics letters Vol. 45; no. 22; pp. 1127 - 1128
• Main Authors: MA, Z, FAN, P, LARSSON, E. G, HONARY, B
• Format: Journal Article
• Language: English
• Published: Stevenage Institution of Engineering and Technology 22.10.2009
• Subjects: Applied sciences; Exact sciences and technology; Information, signal and communications theory; Modulation, demodulation; Signal and communications theory; TECHNOLOGY; TEKNIKVETENSKAP; Telecommunications and information theory; Fading channels; Performance evaluation; Differential detection; Bit error rate; Worst case method; Rayleigh channels; Algorithm; Computational complexity; Time variation; Polynomial time; Time invariance; Relaxation; Symbol detection; Maximum likelihood; Time complexity; Differential modulation; Software radio
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2009.2069

The maximum-likelihood multiple-symbol differential detector (ML-MSDD) has better bit-error-rate performance than many other detectors for differential modulation. Unfortunately, the computational complexity of ML-MSDD quickly becomes prohibitive as the observation window size grows. While low-complexity MSDD algorithms for the time-invariant Rayleigh fading channel have been considered before, there is a need for low-complexity MSDD algorithms for general time-varying Rayleigh fading channels. A polynomial-time complexity approach called semi-definite relaxation (SDR) is employed to achieve differential detection with near maximum-likelihood (ML) performance. The proposed SDR quasi-maximum-likelihood (QML) multiple-symbol differential detection (SDR-QML-MSDD) is efficient in that its complexity is polynomial in the observation window size, even in the worst case, while it exhibits almost the same performance as ML-MSDD does.