A study on receiver performance of a wideband CDMA testbed system for IMT-2000

We have developed a testbed system for wideband code division multiple access (CDMA). This testbed system is equipped with a 2D-RAKE receiver and transmission power control system based on a signal power to noise power ratio (SIR). We report the receiver performance of the testbed system estimated from results of laboratory experiments. This paper describes the influence of the number of fingers under multipath fading environments. As compared with a single-path receiver, a 4-finger RAKE receiver saves an average transmitted power of around 7 to 8 dB, although deterioration of the preciseness of detection due to the increase of the number of paths debases the performance of the receiver. We also discuss the influence of the parameter of transmission power control on receiver performance. When the TPC step=0.5 dB and the TPC period=0.625 ms, the transmission power of around 0.7 to 1.0 dB can be reduced as compared with the result for the TPC step=1.0 dB and TPC period=1.25 ms