Overhearing-based Interference Cancellation for Relay Networks

We consider a wireless downlink system with one transmit base station (BS) and two receive subscriber stations (SS1 and SS2) in full frequency reuse. The primary subscriber (SS1) is served in two hops via a relay station (RS). The second subscriber (SS2) is located relatively close to both BS and RS. In a conventional paradigm, SS2 can not receive its message from BS when either BS or RS serves SS1, since the transmissions for SS1 cause strong interference at SS2. To improve system throughput, we propose an interference cancellation scheme at SS2 that allows BS to serve SS2 while RS relays. Exploiting the identity of the interfering messages in the two hops. SS2 overhears the interfering message at its initial transmission and cancels its interference latter. Theoretical analysis and realistic simulations show that the proposed scheme can significantly and practically boost system throughput.