March 2011
Intermediate
680 pages
25h 12m
English
Chapter 16
MLC Design Using EXIT Analysis
16.1 Introduction
In this chapter, the attainable performance of iteratively detected coded modulation schemes having different block lengths, decoding complexity and an unequal error protection capability is studied, when communicating over AWGN channels using 8PSK modulation. More specifically, the coded modulation schemes investigated include Multilevel Coding (MLC) [81], Trellis-Coded Modulation (TCM) [83], Turbo TCM (TTCM) [57], Bit-Interleaved Coded Modulation (BICM) [84] as well as Bit-Interleaved Coded Modulation using Iterative Decoding (BICM-ID) [90].
With the objective of studying the iterative detection-aided performance of Multistage Decoding (MSD) assisted MLCs, we propose a novel three-dimensional (3-D) EXIT [387] chart for investigating the effects of different symbol-to-bit demapper characteristics. Different constellation labelling strategies have been employed in the context of MLC with the aim of increasing either the Euclidean distance or the Hamming distance associated with the different modulation phasor points in order to achieve a better iterative detection performance with the aid of optimised bit-to-symbol mappers/demappers [364, 371, 388]. Instead of optimising the modem constellation labelling, in this chapter we introduce a serially concatenated unity-rate code [389] having a recursive structure as a precoder in the context of MLC schemes with the aim of enhancing the demapper’s convergence characteristics. ...
