Design of adaptive wireless terminals

The variation in wireless channel conditions with time and position implies that a point solution is not ideal when designing a wireless terminal. To guarantee robustness, a fixed terminal design will compromise performance when operating in a benign channel. Alternatively, a terminal designed strictly for high performance will lack the robustness needed to operate in a hostile channel. Clearly, a preferred strategy would be to allow adaptive tuning of the system parameters to make a continuous robustness/performance trade-off. This leads to many interesting design problems, including how to monitor the channel and develop adaptive techniques to respond to it, as well as how to pick system parameters at all levels to adapt for a given type of channel degradation (interference, frequency selective fading, flat fading etc.) and the particular application requirements. In this paper we present results of the on-going MERLIN project, in which we are building an adaptive wireless terminal and experimenting with a number of adaptive techniques to determine the feasibility and impact of adaptation. The paper concentrates on the design and implementation of the adaptive node.