Opportunistic Cooperative Relaying Protocol for UAV-assisted Flying Adhoc Network
Keywords:FANET, Dual-hop, System Outage Probability, Spatial Diversity, Cooperative Relaying, Relay Selection
A tremendous rise in the use of Unmanned Aerial Vehicles (UAVs) in wireless communication is recently observed. Due to the useful features of UAVs, a new era of over-the-head wireless communication is finding its space at a rapid pace. A range of civilian and military applications is being tested using such UAV-assisted Flying Ad-hoc Networks. In such networks, the quality of communication is usually affected due to fading on channels and limited resources of the UAVs. In this work, we study the outage performance of dual-hop network over Rayleigh fading air-to-ground channels between source UAV and destination Ground Control Station and a group of intermediate UAV aerial relays. We focus on spatial diversity using cooperative relaying through relaying UAVs working in a cooperative manner to support the communication using maximum ratio combining at the destination. The best relay may be selected based on channel state information in terms of signal-to-noise ratio to make the system resource efficient. UAVs are assumed to work in Amplify and Forward mode in Half Duplexed downlink communication scenarios while deriving the closed-form expression for the outage probability. Numerical results are validated using Monte Carlo Simulations to study the impact of various system parameters on performance. The results of proposed non-buffer aided scheme is compared with compulsory direct-only communication. The impact of number of intermediate relays on dual hop links, symmetric and asymmetric channels is studied. The results are compared by changing the data rate and SNR of the links. The results show that cooperative relaying decreases the outage probability. More relays in cooperation, improve the system performance but at the cost of the network increased resources.