Iterative Detection and Decoding for Wireless Communications

Abstract

This report focuses on the application of iterative decoding to various problems encountered in wireless communications. iterative decoding was first developed as a practical means for decoding turbo codes. The first part of this report provides an overview of turbo codes and the main classes of iterative decoding algorithms. Turbo codes are applied to wireless communication networks that require variable quality of service and transmit over unknown fading channels. Next, iterative decoding is applied to the problem of joint multiuser detection (MUD) and forward error correction (FEC) decoding. it is shown that by using iterative decoding to perform joint MUD/FEC- decoding, considerable performance gains can be achieved for multiple-access systems that use highly correlated signals, such as time division multiple access (TDMA). Per- formance is further improved in TDMA systems by using observations from multiple base stations or "macrodiversity". Finally a strategy for combining multiuser detec- tion, FEC decoding, and macrodiversity, termed "cooperative decoding" and suitable for TDMA networks is proposed.