This paper addresses the challenge of efficient rendezvous in multihop cognitive radio networks, where existing channel-hopping algorithms designed for single-hop scenarios incur increased delay and coordination inefficiencies in multinode topologies. To overcome these limitations, we propose a Multihop Dual Modular Clock Algorithm (M-DMCA), which systematically extends modular clock-based rendezvous to multihop environments while preserving efficient channel coordination. The proposed scheme enables dual-channel selection per timeslot and incorporates a lightweight three-way handshake mechanism to improve coordination among intermediate nodes. Simulation results under worst-case conditions, including high primary user activity, asymmetric channel availability, and dense network settings, demonstrate that M-DMCA significantly reduces rendezvous time compared to existing approaches, achieving up to 24% improvement. These results demonstrate the suitability of M-DMCA for timely node discovery in dynamic emergency response scenarios.

翻译：本文针对多跳认知无线电网络中高效汇聚的挑战展开研究。在现有适用于单跳场景的信道跳变算法中，多节点拓扑结构会导致延迟增加和协调效率低下。为克服这些局限，我们提出一种多跳双模时钟算法（M-DMCA），该算法将基于模时钟的汇聚方法系统性地扩展到多跳环境中，同时保持高效的信道协调能力。该方案支持每时隙双信道选择，并引入轻量级三次握手机制以改善中间节点间的协调。在包括高主用户活动、非对称信道可用性和密集网络设置的最坏条件下进行的仿真结果表明，与现有方法相比，M-DMCA显著缩短了汇聚时间，优化幅度高达24%。这些结果证明了M-DMCA在动态应急响应场景中实现及时节点发现的适用性。