Performance analysis of spread spectrum protocols with adaptive spreading

Temporal fading is an inherent characteristic of wireless channels. Furthermore, in a multiuser spread spectrum network, the instantaneous value of the multiple access interference varies with time. As a consequence, the instantaneous signal-to-interference-plus-noise ratio varies from one frame to another. This variation can even occur within a given frame. In this work, we present a new set of analytical and numerical results on Incremental Spreading (IS) protocols that adaptively increase the duration of a frame, or the spreading gain, based on the past instantaneous channel and interference conditions. The control operation is carried out mainly at the receiver end, resulting in a distributed system, unlike other spreading gain control algorithms which are centralized. These protocols are ready to be implemented in single- and multi-carrier code division multiple access (CDMA) type technologies and can enhance the throughput and capacity of wireless networks.