Soft-Length Frame Protocols for Wireless Networks

Temporal fading is an inherent characteristic of wireless channels. Also, 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 also occur within a given frame. In this work, we propose protocols, namely, soft-length frame (SOLF) protocols, that adaptively control the duration of the frame, or the spreading gain, according to the channel and interference conditions. In these protocols, the control operation is carried out mainly at the receiver end, resulting in a distributed system, unlike other variable spreading gain algorithms which are centralized. We implement these protocols in single- and multi-carrier CDMA systems and show that these protocols can enhance the throughput and capacity of wireless networks.