Relay selection with reduced CSI for TWR assisted FSO networks

This paper presents a relay selection scheme for a multiple relayed free-space optical (FSO) communication network. The considered FSO network consists of two non line-of-sight terminal nodes and multiple two-way relays (TWR). In order to establish a communication link between the terminal nodes, two TWRs are selected using partial relay selection protocols. The partial relay selection protocols reduce the channel state information requirements of the system. Further, by using two relays, the advantages of cooperative diversity are achieved. The system performance is evaluated in terms of outage probability, considering an optical channel that is affected by atmospheric turbulence induced fading and pointing errors. Further, the numerical results demonstrate that system performance can be significantly improved by using the proposed relay selection scheme.