How much can we gain by exploiting buffers in wireless relay networks?

Wireless relays will play an important role in future wireless communication networks. This talk will focus on the new concept of buffer-aided relaying. In conventional relay protocols, the schedule of when the different nodes in the network transmit is pre-fixed and non-adaptive. In contrast, buffer-aided relaying protocols exploit the additional degrees of freedom introduced by relays with buffers and employ an adaptive transmission schedule which takes into account the quality of the different links in the network. We will show that this new approach leads to substantial performance improvements in relay networks with fading links. In particular, buffer-aided relays enable significant gains in throughput as well as outage and error probability at the expense of an increased delay. These gains are introduced by adaptive link selection and/or adaptive transmission mode selection. We will first introduce the basic concept of buffer-aided relaying using the example of a simple three node one-way relay network before considering more complex networks such as relay-selection networks, multi-antenna relay networks, and two-way relay networks. We show that in some cases buffer-aided relaying protocols can double both the diversity gain and the throughput compared to conventional relaying protocols. Furthermore, in multi-antenna networks, buffer-aided relaying can also help to overcome the performance loss that half-duplex relays typically suffer compared to full-duplex relays.