On the sensitivity of IMT-DS performance to system parameters

IMT-DS, formerly known as the UTRA system is one of five radio interface standards adopted for the third generation IMT-2000 systems. We present results of our investigation on the sensitivity of IMT-DS performance to variations in the system parameters. In particular, the performance of a multi-rate IMT-DS system is investigated for different RAKE structures, interleaving depths, and Doppler frequencies. An approximate expression for the BER of a RAKE receiver mismatched to the channel is derived. It is shown that the performance is dependent on the inter-path interference. An improvement in performance is obtained if antenna diversity is combined with traditionally used path diversity available in RAKE receivers.