SPACE-TIME TURBO CODES FOR MULTIPLE USERS

Abstract

Increasing demand for bandwidth due to increasing number of users in appli-cations such as cellular telephony, wireless computer networks and broadband local access leads to have communication channels that involve both error-control coding and multiple access signalling. Since the complexity of optimal data detection and decoding makes practical implementation infeasible. Re-cently, iterative multiuser techniques which lowers the complexity of the de-coder have attracted attention. These techniques exploits the turbo principle of the well known turbo codes. In this thesis the iterative multi user detection principle is used between the multi user detector for multiple-access signalling structure and the turbo code as the error control code. This method is often called iterative multi user turbo 'detection. The two detectors exchange soft information in order to achieve increased performance. By employing multiple antennas to both sides of the communication channel to each user, the performance may be increased further. This thesis exploits iterative multi user turbo detection with inclusion of multiple antennas at both sides of the communication channel with focus on the two user 2 x 2 antenna situation.