Buffer-aided link selection for incremental relaying systems

In this paper, we consider a three-node wireless network comprising of a source and two users. Both users need to decode the transmitted data correctly. User 1 has better position to the source than user 2 most of time slots. User 1 has buffer to store the transmitted information by the source. Thus, in the case of wrong decoding at user 2, user 1 can resend data to user 2 some time slots later. In this paper, we propose a novel incremental relaying based adaptive link selection policy that exploits incremental relaying and buffer to maximize the throughput of the network. That is, based on the channel quality of the available links, each time slot is allocated either to the source or user 1 to transmit data. Both delay constrained and delay tolerant transmission schemes are studied. We model the variation of the buffer at user 1 as a Markov Chain and calculate the outage probability of the proposed policy. Our simulation results show that the proposed scheme achieves higher throughput and lower outage probability compared to the recently proposed link selection policies with or without buffer.