Design and Analysis of NCed-HARQ Transmission Scheme for Space Information Networks

With the development of high throughput satellites and space information networks (SINs), broadband satellite communication networks is viewed as an important component to improve system coverage and throughput in the upcoming fifth generation (5G) networks. In this paper, we propose a network coded (NCed) hybrid automatic repeat request (HARQ) transmission scheme for the backbone high throughput satellites in SINs, in order to satisfy the ever-increasing broadband communication service demands. We first present our NCed-HARQ transmission scheme for multiple unicast flows in a practical SIN downlink scenario. Then the mean number of NCed-HARQ transmission rounds is derived. Moreover, a new representation and calculation method by using the Laplace transform for reliable data delivery in NCed-HARQ is also presented, where the derivation of throughput expressions is in a matrix exponential distribution form. Finally, we compare the throughput performance of our NCed-HARQ with NCed-ARQ scheme and HARQ transmission scheme. Simulation results show that our NCed-HARQ transmission scheme can enhance the throughput, especially in the high signal-to-noise region.