March 2011
Intermediate
680 pages
25h 12m
English
Chapter 17
Sphere Packing-aided Space-time MLC/BICM Design1
17.1 Introduction
In Chapter 16 we introduced the concept of EXIT-chart analysis and applied it to both Multilevel Coding (MLC) and Bit-Interleaved Coded Modulation using Iterative Decoding (BICM-ID) schemes in Section 16.3.2. A precoder was also invoked by the modulator in order to achieve a better convergence behaviour for the system. It was shown in [404–406] that the bit-to-symbol mapping plays an integral part in enhancing the attainable coded modulation performance. Signal mapping entails the design process of assigning the bits to the signal constellation set. Various carefully designed 2-dimensional (2-D) and Multi-Dimensional (M-D) bit-to-symbol mapping schemes have been proposed in the literature in order to improve the achievable BER performance [97, 98, 407].
In order to further improve the performance of this MLC scheme, a useful transmit diversity gain can be obtained by introducing Alamouti’s Space-Time Block Codes (STBC) [408]. Alamouti’s concept of STBC was further generalised to an arbitrary number of transmitters by Tarokh et al. [409], but no attempt was made in [408] and [409] to jointly optimise the space-time signal design of the two consecutive time-slots and two transmit antennas. In order to jointly design the space-time signals of the transmit antennas, here we employ a novel Sphere Packing (SP) modulation scheme combined with orthogonal transmit diversity design, which was introduced by Su ...
