On the buffer-aided collaborative relaying scheme for asymmetric parallel relay networks

In this paper, we study a buffer aided collaborative relaying protocol for an asymmetric parallel relay network composed of one source node, two half-duplex decode-and-forward (DF) relays with buffers, and one destination node. The proposed protocol incorporates a two-phase relay communication: in the first phase, one selected relay receives the data from the source and buffers the data; and in the second phase, both relays collaborate with each other and transmit part of buffered data to the destination simultaneously. It is found that the collaborative relaying exploits both temporal and spatial diversity gains in the presence of multiple relays. An optimization scheduling problem is further formulated, taking into consideration the stability of buffers and transmission power. Extensive simulations validate the efficiency of the proposed collaborative relaying protocol.