Channel Hardening-Exploiting Message Passing (CHEMP) Receiver in Large-Scale MIMO Systems

Narasimhan, Lakshmi T and Chockalingam, Ananthanaryanan (2014) Channel Hardening-Exploiting Message Passing (CHEMP) Receiver in Large-Scale MIMO Systems. In: IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING, 8 (5). pp. 847-860.

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Abstract

In this paper, we propose a multiple-input multiple-output (MIMO) receiver algorithm that exploits channel hardening that occurs in large MIMO channels. Channel hardening refers to the phenomenon where the off-diagonal terms of the matrix become increasingly weaker compared to the diagonal terms as the size of the channel gain matrix increases. Specifically, we propose a message passing detection (MPD) algorithm which works with the real-valued matched filtered received vector (whose signal term becomes, where is the transmitted vector), and uses a Gaussian approximation on the off-diagonal terms of the matrix. We also propose a simple estimation scheme which directly obtains an estimate of (instead of an estimate of), which is used as an effective channel estimate in the MPD algorithm. We refer to this receiver as the channel hardening-exploiting message passing (CHEMP) receiver. The proposed CHEMP receiver achieves very good performance in large-scaleMIMO systems (e.g., in systems with 16 to 128 uplink users and 128 base station antennas). For the considered large MIMO settings, the complexity of the proposed MPD algorithm is almost the same as or less than that of the minimum mean square error (MMSE) detection. This is because the MPD algorithm does not need a matrix inversion. It also achieves a significantly better performance compared to MMSE and other message passing detection algorithms using MMSE estimate of. Further, we design optimized irregular low density parity check (LDPC) codes specific to the considered large MIMO channel and the CHEMP receiver through EXIT chart matching. The LDPC codes thus obtained achieve improved coded bit error rate performance compared to off-the-shelf irregular LDPC codes.

Item Type:	Journal Article
Publication:	IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING
Publisher:	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Additional Information:	Copy right for this article belongs to the IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA
Keywords:	Channel estimation; channel hardening; decoding; detection; large-scale MIMO systems; message passing
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	12 Nov 2014 05:16
Last Modified:	12 Nov 2014 05:16
URI:	http://eprints.iisc.ac.in/id/eprint/50225

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