Optimization of Two-Way Network Coded HARQ With Overhead
Hongyi Zhu, Besma Smida, David J. Love · IEEE Transactions on Communications · 2020
To account for the ever-increasing demand for wireless broadband, it is critical to develop new techniques that can increase throughput. Network-coded (NCed) hybrid automatic repeat request (HARQ) has previously been shown to hold much potential for increasing network throughput by utilizing the retransmissions and side-information. However, the previous performance analysis did not take into account that the implementation of NCed HARQ requires additional control information that indicates which packets are included in one network coded packet and additional ARQ acknowledgements for the packets overheard by the unintended users. In this paper, we analyze the resources required for additional overhead and derive the outage probability and throughput for both downlink and uplink. With the analytical expressions and Monte Carlo simulation results, we study the trade-off between the maximum number of users (MNU) for NCed HARQ system and the overall throughput. Finally, we numerically show the existence of the optimal MNU and derive an approximate closed-form expression for the optimal value.