Analysis of an Adaptive Selective-Reject Scheme in Time-Varying Channel with Non-Negligible Round-Trip Delay and Erroneous Feedback

In this article, an adaptive SR ARQ scheme is analyzed and optimized in a time-varying channel environment with unreliable feedback. To have an operational scheme, we choose the smaller packet size to be half of the bigger one. Thus, there is only one independent design parameter related to packet size. The other two parameters are associated with channel sensing. The performance of the adaptive scheme is measured by its average throughput, which is upper-bounded by the throughput of the so-called ideal adaptive scheme. This upper bound is very useful in the optimization of the packet size and other design parameters.