On the Influence of Beamwidth on Jammed Tactical Radio Communication with Beam Misalignment

The usage of directional antennas in wireless communication provides a higher gain between transmitter and receiver and a higher robustness against interferences. Tactical networks are prone to hostile attacks. Antennas with a high gain can thus be very beneficial for tactical operations as jamming is more likely to be suppressed. The smaller the antenna beamwidth, the higher the gain and the suppression of interferences from other directions. However, the positions of the other nodes within the network need to be known. The estimation of the positions naturally introduces uncertainty. This leads to a beam misalignment. The narrower the antenna beamwidth, the more critical is the position estimation error. Adapting the antenna beamwidth by using the gained spectrum awareness can be applied e.g., in Cognitive Radio. In this paper, the trade-off between antenna bandwidth, interference suppression and link stability is investigated. The simulation results indicate that even though a narrow antenna beam helps to suppress a hostile jammer's influence, a very small antenna beamwidth can lead to a higher packet loss in the presence of a jammer when there is a large beam misalignment.