Abstract:

To improve the spectrum efficiency and reliability of relay system, two transmission protocols combined network coding and hybrid automatic repeat request (HARQ) are proposed, the HARQ protocol is based on determination network coding(DNC-HARQ) ,and the HARQ protocol is based on opportunity network coding(ONC-HARQ). The performance of outage probability of system and the spectrum efficiency of these two protocols are analyzed. Furthermore, an optimize problem is elicited to maximize the spectrum efficiency of system. As the optimize problem is nonconvex, an iterative algorithm is designed to solve it. Simulations confirm that the two protocols presented is with higher reliability than the protocol with network coding, more spectrum efficiency of systems is obtained than the protocol with HARQ. Simulation shows the iterative algorithm designed can effectively maximize the spectrum efficiency of system.

Key words: network coding, hybrid automatic repeat request protocol, relay, cross-layer optimization