Adaptive power and rate transmission in hybrid DS/FH CDMA communications over fading channels

We consider a hybrid direct-sequence frequency-hopped (DS/FH) code division multiple access (CDMA) communication system, where the transmission power and data rate are adapted relative to the channel variation. Instead of random frequency hopping, hopping pattern is adap- tively adjusted to obtain the maximum channel gain among available fre- quency slots. Transmission power and/or data rate are also adapted such that a target transmission quality is maintained. It is shown that the pro- posed scheme provides a higher average data rate than pure DS/CDMA with power and rate adaptations, subject to the identical average trans- mission power and bandwidth constraints.