Analysis of High Rate Punctured Trellis Coded M-APSK for Multimedia Data Transmissions

Abstract

Towards effective Digital Video Broadcasting (DVB) of multimedia data, the current DVB standards specify the use of FEC (Forward Error Correction) coding combined with M-APSK (Amplitude-Phase Shift Keying) as well as MPSK (Phase Shift Keying) of various code rates. As to the FEC, concatenated coding (BCH outer code and LDPC inner code) is required to yield different coding gains per different modulation schemes. In this paper, the use of higher rates (3/4 and 4/5) punctured Trellis Coded Modulated (TCM) M-APSK (for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{M}=16$</tex> and 32) is proposed. The complicated concatenated coding process can be replaced by TCM, which not only avoid the use of two different layers of encoding and the modulation scheme into a single task for better efficiency. In addition, by introducing puncturing technique in TCM, the basic rate ½ encoder can be used to produce any higher rate codes, which supports the idea of Adaptive Coding and Modulation (ACM) in new DVB standards. Since puncturing the codes effectively reduces the parallel paths in higher modulation schemes, the performance gain is drastically improved. Specifically, in this work, higher rates (3/4 and 4/5) punctured Trellis codes are combined with 4-states 16-APSK and 16-states 32-APSK. Based on the respective set partitioning, weight distribution functions are obtained towards the final derivation of error probability based on the transfer function analysis. Results of the extensive computer simulation under AWGN validate the accuracy of derivation and effectiveness of the proposed punctured high-rate TCM combined with M (16 and 32)-APSKs when compared with the 16-PSK and 32-PSK (both un-coded and Coded) by yielding significant gains.