Performance evaluation of space-path diversity and higher alphabet size for CDMA

For the next generation mobile systems, the design of high speed reliable wireless communications supporting data, image and voice transmission is of primary interest. Current cellular DS-CDMA systems have been designed to operate at low- or medium-bit rate transmission, of 9.6 or 14.4 kbits/s, but proposals to increase this data rate to 64 kbits/s, 384 kbits/s and 2 Mbits/s are currently being evaluated by the standard committees such as the Universal Mobile Telecommunications Service (UMTS or IMT-2000). We investigate the performance achievable by an asynchronous DS-CDMA system operating at data rates of up to 8 Mbits/s in conjunction with either QPSK or 16-QAM modulation and space-path diversity techniques in a frequency selective channel.