Flow optimization in parallel relay networks with cooperative relaying

Abstract

We investigate the relaying problem in parallel relay networks consisting of a source sending information to a destination via multiple relays. To exploit the broadcasting nature of the wireless channel, the source broadcasts to the relays and the relays forward the decoded information to the destination. The flow rates on all links in the network are selected to minimize the average transmit power required. We consider two optimal protocols, respectively in which the relays forward the decoded information phase-synchronously and phase-asynchronously. It turns out that not all relays forward information in the optimal phase-asynchronous protocol. Using this fact, we propose a sub-optimal protocol employing at most two relays. In phasesynchronous relaying, the optimal protocol gives around 1dB and over 3dB improvements compared at the outage probability of 10 −4 with respect to the single-relay optimal protocol at low-rate and high-rate requirements, respectively. Again, we propose a two-relay sub-optimal protocol for phase-synchronous transmission. Simulation results indicate that these sub-optimal protocols give performances that are close to the performances of the optimal protocols and superior to that of the single-relay optimal protocol.

Cooperative Transmission in a Wireless Relay Network Based on Flow Management

“…We also note that the proposed FO and GLS protocols can be used in wireless networks with topologies more complicated that the wireless relay network considered here. For example, application of similar ideas to a parallel relay network in which there is no direct connection between the source and the destination is considered in [21].…”

Utilizing Spectrum Efficiently (USE)

“…Employing these basic components, simple information flow designs were constructed to achieve the optimal diversity-multiplexing tradeoff for a simple relay channel [8]. Extensions were made to our flow-based cooperative design to wireless networks with more complicated topologies, including a fully connected wireless cluster [7,32], a parallel relay network [11,31], a cooperative multiple-access channel [6,29], and a cognitive relay network [17].…”

Grouping Algorithm for Partner Selection in Cooperative Transmission

“…Practical coding schemes for cooperative broadcasting are investigated in [28] and [29], while successive interference cancelation is considered in [30]. Recently, GBC is considered in different communication systems [18,19,[31][32][33].…”