WirelessPersonal Communications 1:61-89, 1994. 61 @ 1994 KluwerAcademic Publishers. Printedin the Netherlands. Simulation of the Uplink of JD-CDMA Mobile Radio Systems with Coherent Receiver Antenna Diversity Peter Jung, Josef Blanz, Markus Nal3han & Paul Walter Baier University of Kaiserslautern, Research Group for RF Communications, P O. Box 3049, D-67653 Kaiserslautern, Germany. Phone: ++49 631 205 2918, Fax." ++49 631 205 3612, E-mail: blanz@rhrk.uni-kl.de Abstract Due to time variant multipath propagation, both intersymbol interference and multiple access interference occur at CDMA receivers. These degrading effects can be combatted by joint detection (JD) techniques. In order to reduce the performance impairments resulting from time variance, coherent receiver antenna diversity (CRAD) can be used. In the present paper, a system model of CDMA mobile radio systems using various JD techniques in combination with CRAD shall be considered. This system model is an evolution of the pan-European GSM and takes important real world aspects such as imperfect channel estimation, nonlinear amplification and D/A and A/D conversion into account. The viability of JD with CRAD shall be demonstrated by bit error rate simulations of this system model. It is shown that by using JD with two receiver antennas in bad urban areas, Eb/No < 8 dB per antenna is sufficient for a bit error rate of 10 -2, and Eb/NO < 11 dB per antenna is required for a bit error rate of 10 .3" 1. Introduction In mobile radio systems, two basic problems must be solved, namely the multiple access (MA) problem, arising due to the simultaneous transmission of signals associated with several active users that share the same transmission medium, and the equalization problem, arising due to time variant and frequency selective mobile radio channels [1, Chapter 5]. An attractive solution to the MA problem is code division multiple access (CDMA) which is currently under discussion for the application to third generation digital mobile radio systems, cf. e.g. [2-4]. Since in CDMA mobile radio systems the signals of various users are present at the same time in the same frequency band, both intersymbol interference (ISI) and multiple access interference (MAI) occur which can be combatted by using joint detection (JD) techniques allowing the simultaneous detection of the different signals [5]. CDMA mobile radio systems using JD shall be termed JD-CDMA mobile radio systems in the sequel. Unfortunately, the maximum-likelihood JD technique presented in [6] is prohibitively expensive for which reason suboptimum JD techniques, see e.g. [7, 8], are more favourable. The suboptimum JD techniques given in [7] were developed for burst transmission systems. Therefore, burst transmission shall be considered in what follows. A JD-CDMA mobile radio system with burst transmission was presented in [9] which represents the basis of this communication. With respect to a moderate hardware expense of receivers for JD-CDMA mobile radio systems, synchronization between the users, i.e. mobiles and base stations, is favourable. Hence, both burst as well as chip synchronization must be performed. The burst synchronization is based on the time division multiple access (TDMA) component, inherent in the considered JD-CDMA mobile radio system [9], by using particular access and synchronization bursts as it is the case e.g. in the pan-European GSM [ 10]. Since the problem of burst synchronization shall not be covered in this paper, the reader is referred to the GSM recommendations for details. It is assumed that burst synchronization