Data transmission scheduling considering short-term fading for transmit power reduction in CDMA systems

A new data transmission scheduling scheme considering short-term fading conditions in the downlink of code-division multiple access (CDMA) systems is proposed. In this scheduling method, a mobile station (MS) connected to a base station (BS) estimates the fading condition of the next frame based on the received signal power variation and feeds back this information to the corresponding BS. The BS determines the MSs to which it transmits data based on the fading information from the MSs. Analytical and simulation results show that the proposed scheme saves the transmit power greatly when the speed of an MS is relatively low and the Rician factor is small. The maximum amount of the power reduction is about 9 dB. This reduced transmit power results in the data throughput increase of CDMA systems.