Low-Resolution Quantization in Phase Modulated Systems: Optimum Detectors and Error Rate Analysis

• Published in: IEEE open journal of the Communications Society Vol. 1; pp. 1000 - 1021
• Main Authors: Gayan, Samiru, Senanayake, Rajitha, Inaltekin, Hazer, Evans, Jamie
• Format: Journal Article
• Language: English
• Published: New York IEEE 2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Counters; Detectors; diversity order; Error analysis; Error correction; Error detection; Error probability; Fading; Fading channels; Low-resolution ADCs; Lower bounds; maximum likelihood detectors; Measurement; MIMO communication; Modulation; Phase shift keying; Quadratures; Quantization (signal); symbol error probability; Wireless communication
• ISSN: 2644-125X; 2644-125X
• DOI: 10.1109/OJCOMS.2020.3010514

This paper studies optimum detectors and error rate analysis for wireless systems with low-resolution quantizers in the presence of fading and noise. A universal lower bound on the average symbol error probability (SEP), correct for all M-ary modulation schemes, is obtained when the number of quantization bits is not enough to resolve M signal points. In the special case of M-ary phase shift keying (M-PSK), the maximum likelihood detector is derived. Utilizing the structure of the derived detector, a general average SEP expression for M-PSK modulation with n-bit quantization is obtained when the wireless channel is subject to fading with a circularly-symmetric distribution. For the Nakagami-m fading, it is shown that a transceiver architecture with n-bit quantization is asymptotically optimum in terms of communication reliability if n ≥ log 2 M + 1. That is, the decay exponent for the average SEP is the same and equal to m with infinite-bit and n-bit quantizers for n ≥ log 2 M + 1. On the other hand, it is only equal to 1/2 and 0 for n = log 2 M and n <; log 2 M, respectively. An extensive simulation study is performed to illustrate the accuracy of the derived results, energy efficiency gains obtained by means of low-resolution quantizers, performance comparison of phase modulated systems with independent in-phase and quadrature channel quantization and robustness of the derived results under channel estimation errors.