We previously proposed a next generation cellular system for IMT-2000 based on the Wideband DS-CDMA with TDD scheme (W-CDMA/TDD) and have evaluated its performance by computer simulation, laboratory and field experiment. With the W-CDMA/TDD, because of its correlation between the downlink and the uplink, transmission and reception space diversity (SD) at a base station and open-loop transmit power control (TPC) can be simply realized. This paper reports performance of laboratory and field experiments using a developed testbed. The results shows it has been confirmed that transmission and reception SD and open-loop TPC have sufficient performance under a field environment as well as laboratory environment.

We previously proposed a next generation cellular system for IMT-2000 based on wideband DS-CDMA with TDD scheme and have evaluated its performance by computer simulation, laboratory and field experiments. This paper presents the design concept of TDD-mode operation on wideband DS-CDMA systems. These systems employ almost the same techniques with a little difference as FDD-mode. We also present the schemes of the TDD-mode specific techniques such as fast cell search, transmission diversity and transmitter power control and show the evaluation results of them are effective. Performance can be improved by use of enhanced techniques such as interference cancellation and adaptive antenna array diversity.