Multisensor interference cancellation performance in asynchronous uplink on MC-CDMA systems

Abstract

All CDMA based systems are essentially limited by multiple access interference (MAI) caused by the loss of orthogonality between transmitted signals occurred from multipath propagation. In the uplink the lack of synchronism between transmitting mobile terminal equipments also adds up to that impairment. Multiuser detection (MUD) techniques are appropriate to mitigate the MAI problem and interference cancellation (IC) detectors are amongst the most useful techniques for providing efficient implementations for that purpose. Also, it is well known that antenna arrays are another key technique in order to achieve high capacity in emerging wireless systems. In this communication we focus on the two basic IC architectures, SIC and PIC, exploiting through combination multiple signal versions collected by an antenna array. The performance of these multisensor IC detectors, designed for asynchronous uplink transmission on MC-CDMA based systems, is evaluated through computer simulations for characteristic scenarios of the broadband component of future cellular systems. The numerical results show that significant improvements can be achieved when combining spatial diversity and IC based MUD techniques, against conventional single user detection (SUD).