Reduced complexity blind rate detection for second and third generation cellular CDMA systems

In the North American CDMA standards IS-95 and cdma2000, variable data rates are used according to the detected voice activity and the supported data services. For bit rates not exceeding 14.4 kbit/s, the rate information is not provided to the receiver and therefore has to be detected by hypothesis testing called blind rate detection. In this paper, a novel two-stage rate detection algorithm is proposed. First, a coarse rate estimation is performed. Through verifying the estimation using a second criterion, the data rate can be detected with a high probability without testing all possible data rates. Using this algorithm, 91% of the received frames need to be decoded only once resulting in a significantly decreased power consumption of the channel decoder of 60% without having any performance loss when compared to conventional rate detection.