Packet Transmission over a Fixed Wireless Loop Using Adaptive Rate Techniques

In this paper a rate-adaptive transmission scheme is used to ensure reliable and efficient transmission of packets over a fixed wireless link. The scheme is based on a stationary, memoryless, and block-fading channel model with perfect knowledge of channel fading state, available at transmitters. Information, in our proposed system, is transmitted in the form of packets that each may potentially consist of several conventional ATM cells along with a rate-identifier preamble that contains the information needed by a receiver, allowing for proper demodulation/decoding of packets. In this application, because of the short physical length of a radio link, a simple go-back-N ARQ protocol can provide a reliable communications system with an acceptable throughput. Analytical results for spectral efficiency, throughput and queuing delay show that adaptive-rate systems can achieve significant improvements over those using fixed-rate schemes.