Combination of DOA and beamforming in position-based routing for underlay cognitive wireless networks

This work presents a routing strategy for underlay cognitive wireless networks combining a position-based routing protocol, with position information obtained by means of Direction Of Arrival (DOA) estimation, with beamforming. Beamforming takes advantage of the estimated DOAs to maximize Signal-to-Noise Ratio at the intended receiver while minimizing interference towards potential victim receivers, either cognitive or primary. The paper first introduces the location-based routing protocols considered in this work; next, the DOA estimation and beamforming techniques adopted in conjunction with the routing protocol are described. The proposed strategy is then presented and evaluated by means of computer simulations. Simulation results highlight the increase in network performance in terms of end-to-end throughput guaranteed by the proposed strategy, thanks to the reduction of internal interference experienced by cognitive terminals as a result of the introduction of beamforming combined with the decrease in control packets transmissions guaranteed by the use of position information.