Joint source and channel decoding (JSCD) has been proved to be an effective technique which can improve decoding performance by exploiting residual source redundancy. Most previous publications on this subject focus on a traditional coding scheme in which the source variable-length coding (VLC) is serially concatenated with a channel code. In this paper, a parallel concatenated coding scheme for the VLC combined with a turbo code is presented. By merging a symbol-level VLC trellis with a convolutional trellis, we construct a symbol-level joint trellis with compound states. Also, a solution of the symbol-by-symbol a posteriori probability (APP) decoding algorithm based on this joint trellis is derived, which leads to an iterative JSCD approach in the similar way to the classical turbo decoder. The simulation results show that our joint source-channel en/decoding system achieves some gains at the cost of increasing decoding complexity, when compared to the joint iterative decoding based on the bit-level super trellis for the separate coding system.

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Joint source-channel coding/decoding (JSCC/JSCD) techniques in flow media communications have become a state-of-the-art and one of the challenging research subjects in the spatial communication area. They have great application prospective and deep impact in various manned space flights, satellite missions, mobile radio communications and deep-space explorations. In the last few years, there have been influential achievements in JSCC/JSCD studies. This paper aims at an introduction to the basic principles of joint source-channel optimal design. A general summarization and classification for various existing JSCC/JSCD methods is addressed. Also presented is a JSCD scheme based on variable-length coding, capable of providing reliable resolutions for flow media data transmission in spatial communications.

In this paper, we have proposed a joint source-channel coding/decoding approach by combining RVLC and VLC for CCSDS IDC coefficients, which can be applied in space communication. In the CCSDS IDC standard, the DC coefficients are given special protection by using a reversible coding/decoding scheme since they are especially significant for the reconstructed image quality. Specifically, the DC coefficients are encoded by reversible variable length codes (RVLCs) after using alternating run-length encoding, which can simplify the code-table design and decrease the decoding complexity by transforming the variable length coded DC coefficients into very few symbols. Simulation results show that this approach can greatly alleviate error propagation and improve the error-resilient performance of the DC coefficients, which can greatly improve the transmitted image quality.

This paper presents joint source channel variable length (VL) coding/decoding based on a space trellis. Through constructing a joint decoding plane trellis, better decoding performance can be achieved than by using the bit-level decoding algorithm. However, the plane trellis is complicated, which results in high decoding complexity for decoding VL turbo codes. To solve this problem, we construct a space trellis and design a low-complexity joint decoding algorithm with a variable length symbol-a posteriori probability (VLS-APP) algorithm in resource constrained deep space communication networks. Simulation results show that the proposed approach reduces the decoding complexity by 10% compared with the plane trellis, and the gain of E b /N 0 is about 0.2 dB at SER = 10 −4 . Furthermore, it provides substantial error protection for variable-length encoded image data. CitationWu W R, Tu J, Tu G F, et al. Joint source channel VL coding/decoding for deep space communication networks based on a space trellis.