Training, Feedback and Delay: Tradeoffs in Wireless Communication Systems

Feedback has traditionally been used to either to learn the channel state, or to request the re-transmission of a failed reception. Despite the established link between the accuracy of the channel state and the performance of the re-transmission protocols, these two feedback usages have been commonly studied separately – one in the physical-layer and the other in the network-layer. For practical wireless systems, the forward and reverse links should be modeled as fading channels, and the tradeoff between bits spent on learning the channel, automatic repeat request (ARQ) bits, and data bits, must be carefully modeled and incorporated into the overall performance. We develop a generalized framework for analyzing the throughput performance of 1) two-way wireless networks with infinite block-length 2) two-way wireless networks with finite block-length 3) network coded ARQ with extra acknowledgement. Furthermore, we investigate how the throughput can be optimized by increasing the packet efficiency.