Design of Joint Sparse Graph for OFDM System

Author

Lei Wen ; Razavi, Razieh ; Imran, Muhammad Ali ; Pei Xiao

Author_Institution

Inst. for Commun. Syst., Univ. of Surrey, Guildford, UK

Volume

14

Issue

4

fYear

2015

fDate

Apr-15

Firstpage

1823

Lastpage

1836

Abstract

Low density signature orthogonal frequency division multiplexing (LDS-OFDM) and low density parity-check (LDPC) codes are multiple access and forward error correction (FEC) techniques, respectively. Both of them can be expressed by a bipartite graph. In this paper, we construct a joint sparse graph combining the single graphs of LDS-OFDM and LDPC codes, namely joint sparse graph for OFDM (JSG-OFDM). Based on the graph model, a low complexity approach for joint multiuser detection and FEC decoding (JMUDD) is presented. The iterative structure of JSG-OFDM receiver is illustrated and its extrinsic information transfer (EXIT) chart is researched. Furthermore, design guidelines for the joint sparse graph are derived through the EXIT chart analysis. By offline optimization of the joint sparse graph, numerical results show that the JSG-OFDM brings about 1.5-1.8 dB performance improvement at bit error rate (BER) of 10^-5 over similar well-known systems such as group-orthogonal multi-carrier code division multiple access (GO-MC-CDMA), LDS-OFDM, and turbo structured LDS-OFDM.

Keywords

OFDM modulation; decoding; forward error correction; graph theory; iterative methods; multiuser detection; parity check codes; EXIT chart; FEC decoding; FEC techniques; JMUDD; JSG-OFDM; LDPC codes; LDS-OFDM; bipartite graph; extrinsic information transfer chart; forward error correction techniques; joint multiuser detection; joint sparse graph; low density parity-check codes; low density signature orthogonal frequency division multiplexing; multiple access techniques; offline optimization; Detectors; Iterative decoding; Joints; Multicarrier code division multiple access; OFDM; Receivers; Code division multiple access; Joint multiuser detection and FEC decoding; Joint sparse graph; Multi access communication; Multiuser channels; code division multiple access; joint multiuser detection and FEC decoding; joint sparse graph; multiuser channels;

fLanguage

English

Journal_Title

Wireless Communications, IEEE Transactions on

Publisher

ieee

ISSN

1536-1276

Type

jour

DOI

10.1109/TWC.2014.2373379

Filename

6964791