A Transmission Scheme Based on Uniform Shortening LDPC Codes for Performance Improvement in Faster-Than-Nyquist Systems

Tanatsan Khantha,Virasit Imtawil,Nararat Ruangchaijatupon,Pirat Khunkitti,Puripong Suthisopapan

doi:10.1109/access.2022.3160167

Tanatsan Khantha, Virasit Imtawil + Show 3 more

Open Access

https://doi.org/10.1109/access.2022.3160167

Copy DOI

Abstract

Faster-than Nyquist (FTN) signaling is a research topic that has been drawing increased attention due to its capability of improving transmission speed without the need of extra bandwidth. However, the deployment of FTN signaling introduces inter-symbol interference (ISI) which severely degrade system performance. Interestingly, even without ISI equalizer, it has been recently shown that the joint application of LDPC codes with FTN signaling can exhibit rather good performance. To further improve the performance of LDPC codes over FTN systems, a transmission scheme that utilizes uniform shortening LDPC codes is proposed in this paper. It was found that their shortening counterpart can provide a coding gain at least 0.4 dB over a wide range of FTN factors compared with FTN systems that employ conventional LDPC codes. Moreover, using LDPC coded ISI-free system as the benchmark, the proposed transmission scheme can possibly provide 43% improvement in data rate with rather small performance degradation.

Highlights

T HE phenomenon in which one transmitted symbol interferes with consecutive symbols is called inter-symbol interference (ISI)
In order to improve the performance of low-density parity-check (LDPC) coded Faster-than Nyquist (FTN) system, a transmission scheme based on FTN signaling and shortening LDPC codes is proposed in this paper
It is clearly seen that the BER performance of the proposed transmission scheme significantly outperforms that of random shortening LDPC codes

Summary

INTRODUCTION

T HE phenomenon in which one transmitted symbol interferes with consecutive symbols is called inter-symbol interference (ISI). Instead of using that kind of pulse shaping, it is reported that the use of root raised-cosine (rRC) waveforms with FTN signaling can provide better performance [6] This type of waveform can lower the distance from 0.802 to 0.703. FTN signaling is corrupted by ISI and the noise in communication channel This problem is known to be solved by a technique called as channel coding. In order to improve the performance of LDPC coded FTN system, a transmission scheme based on FTN signaling and shortening LDPC codes is proposed in this paper. Shortening techniques are used to construct ratecompatible codes [17] but in this work, it will be purposely utilized to combat ISI effect from FTN systems, which has never been studied in the literature before. Our proposed transmission scheme employs the FTN systems with uniform shortening LDPC code.

SYSTEM MODEL

SHORTENING TECHNIQUE

THE PROPOSED TRANSMISSION SCHEME

RESULTS AND DISCUSSIONS

CONCLUSION