Multiple symbol decoding of differential space-time codes
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Abstract
Multiple-symbol detection of space-time differential codes (MS-STDC) decodes N consecutive space-time symbols using maximum likelihood (ML) sequence detection to gain in performance over the conventional differential detection scheme. However its computational complexity is exponential in N . A fast algorithm for implementing the MD-STDC in block-fading channels with complexity O(N 4) is developed. Its performance in both block-fading and symbol-by-symbol fading channels is demonstrated through simulations. Set partitioning in hierarchical trees (SPIHT) coupled with rate compatible punctured convolution code (RCPC) and cyclic redundancy check (CRC) is employed as a generalized multiple description source coder with robustness to channel errors. We propose a serial concatenation of the above with a differential space-time code (STDC) and invoke an iterative joint source channel decoding procedure for decoding differentially space-time coded multiple descriptions. Experiments show a gain of up to 5 dB in PSNR with four iterations for image transmission in the absence of channel state information (CSI) at the receiver. A serial concatenation of SPIHT
- RCPC/CRC is also considered with space-time codes (STC) instead of STDC. Experiments show a gain of up to 7 dB with four iterations in the absence of CSI