On the performance and complexity of irregular variable length codes for near-capacity joint source and channel coding

Maunder, R.G., Wang, J., Ng, S.X., Yang, L-L. and Hanzo, L. (2008) On the performance and complexity of irregular variable length codes for near-capacity joint source and channel coding. IEEE Transactions on Wireless Communications, 7, (4), 1338-1347. (doi:10.1109/TWC.2008.060891).


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In this paper we propose a novel Irregular Variable Length Coding (IrVLC) scheme for near-capacity joint source and channel coding. We employ a number of component Variable Length Coding (VLC) codebooks having different coding rates for encoding particular fractions of the input source symbol stream. These fractions may be chosen with the aid of EXtrinsic Information Transfer (EXIT) charts in order to shape the inverted EXIT curve of the IrVLC codec for ensuring that it does not cross the EXIT curve of a serially concatenated channel codec. In this way, an open EXIT chart tunnel may be created even at low SNR values that are close to the capacity bound of the channel. We propose iteratively decoded serially concatenated IrVLC designs amalgamated with Trellis Coded Modulation (TCM). These schemes are shown to be capable of operating within 0.6 dB of the uncorrelated narrowband Rayleigh fading channel's capacity bound using an average interleaver length of 217,500 bits and an effective bandwidth efficiency of 1.56 bit/s/Hz, assuming ideal Nyquist filtering. By contrast, the equivalent-rate regular VLC-based bench-marker schemes were found to be capable of operating at a higher distance of 1.1 dB from the capacity bound, which is nearly twice that of the proposed IrVLC-TCM scheme. Additionally, an Irregular Convolutional Coding (IrCC) based bench-marker was found to be capable of operating at 0.8 dB from the capacity bound, owing to its slightly eroded performance when operating with the considered interleaver length

Item Type: Article
Digital Object Identifier (DOI): doi:10.1109/TWC.2008.060891
ISSNs: 1536-1276
Related URLs:
Keywords: variable length coding, VLC, iterative decoding, EXIT chart matching, serial concatenation, joint source and channel coding, trellis, BCJR, soft, irregular coding, free distance, computational complexity, capacity, RVLC, VLEC, reversible variable length coding, variable length error correction coding, TCM, trellis coded modulation
Divisions : Faculty of Physical Sciences and Engineering > Electronics and Computer Science > Southampton Wireless Group
ePrint ID: 264467
Accepted Date and Publication Date:
1 April 2008Published
Date Deposited: 05 Sep 2007
Last Modified: 31 Mar 2016 14:09
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/264467

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