Optimality of threshold transmission policies in Gilbert Elliott fading channels

We derive stochastic control algorithms to achieve the optimal tradeoff between throughput and energy consumption for transmitting packets across a time varying wireless channel with memory. The channel state is not directly observed and hence transmission decisions must be based on ACK/NAK information provided over a feedback channel. By reformulating the problem as a Markovian search problem, we propose a conjecture that the optimal transmission control policies are threshold in nature. Threshold policies are computationally inexpensive to implement. Numerical simulations demonstrate the performance improvements that can be obtained using the optimal threshold policies as compared to heuristic algorithms.