Design of Joint Source-Channel Codes Based on a Single Protograph

Abstract

In this paper, we propose using a single protograph to design joint source-channel codes (JSCCs). We present a generalized algorithm, called protograph extrinsic information transfer for JSCC algorithm (PEXIT-JSCC algorithm), for analyzing the channel threshold of the proposed JSCC. We also propose a source single protograph EXIT (SSP-EXIT) algorithm, which is more generic than the generalized source protograph extrinsic information transfer (GSP-EXIT) algorithm, for evaluating the source threshold of a single protograph. Moreover, a collaborative optimization method based on the SSP-EXIT and PEXIT-JSCC algorithms is proposed to construct single-protograph JSCCs with good source and channel thresholds. Finally, we construct single-protograph JSCCs, analyze their decoding thresholds, and compare their theoretical and error performance with JSCC systems based on optimized double-protographs. Results show that our proposed codes can outperform double-protograph-based JSCCs.

Joint Source-Channel Coding System for 6G Communication: Design, Prototype and Future Directions

“…The optimized P-LDPC codes, (B s1 , B c1 ), deriving from [84], are chosen in that such code pair can achieve a decoding threshold of - VOLUME 11, 2023 2.1 dB, 1.5dB lower than the classic (B R4JA , B AR4JA ) [85]. Besides, in general, P-LDPC codes [86] also offer rapid encoding and decoding structures and achieve the linear minimum Hamming distance, leading to a better performance in the waterfall region and the error-floor region of BER curves. In what is called the lifting method for (B s1 , B c1 ), the JSCC matrix can be written as…”