Collaboration-Based Neighbor Discovery Protocol in UAV Network With Directional Antennas

To enhance the anti-interference capability of unmanned aerial vehicle (UAV) networks, many UAV nodes are now equipped with directional antennas. However, their narrow beamwidth significantly increases the latency of neighbor discovery. In conventional neighbor discovery protocols, each node scans independently, leading to redundant discoveries as adjacent nodes repeatedly scan the same regions. To optimize this process, we propose Co-ND, a collaborative neighbor discovery protocol that enables a discovering node to offload part of its scanning workload to neighboring collaborators. This protocol not only accelerates the discovery process while preserving discovery completeness. To analyze the performance of Co-ND, we first model neighbor discovery as a state-transition process and derive a recursive expression for the delay. Then, by applying the additive drift principle, we calculate the upper and lower bounds and a closed-form approximation for the delay, theoretically proving its advantages in delay reduction. Finally, we conduct extensive simulations under various settings. The results show that Co-ND significantly outperforms existing schemes in neighbor discovery latency, especially in narrow-beam scenarios.