Previously, dynamic multi-hop shortcut (DMHS) communications to improve packet delivery rate and reduce end-to-end transmission delay was proposed. In this letter, we theoretically derive the end-to-end throughput of DMHS considering the retransmission at each node for a simple network model without considering collision. Moreover, we show the validity of the derived expression using computer simulations, and we clarify the effect of various parameters on the throughput using DMHS.

After the popularization of sensor networks, the size of the monitoring region and the number of sensor nodes will grow to an enormous scale. In such large-scale sensor networks, multi-hop communications between sensor nodes will be necessary to cover the whole monitoring region. Moreover, sensor nodes should be grouped into clusters to enhance scalability and robustness. Therefore, we believe that multi-hop communication between clusters is preferable for large-scale sensor networks. To clarify the fundamental characteristics of this form of communication, we analytically derive the network's power consumption and compare it with other routing methods using TDMA communication and an interference-free transmission schedule. The results show multi-hop communication between clusters is preferable in large-scale sensor networks because it can alleviate heavy relaying loads near the sink node and it has a shorter data collection time compared with simple multi-hop communications without clusters. Knowing how much performance degradation arises when interference is unavoidable is essential for multi-hop communications in clustered sensor networks. Therefore, we compare interference-free TDMA communication with CSMA/CA communication which can cause interference in clustered sensor networks. Consequently, we show that although the data collection time is about 3.7 times longer when using CSMA/CA, the power consumption can be suppressed to 12%.

Single-hop communication methods of the current wireless network cannot meet new demands in new domains, especially ITS (Intelligent Transport Systems). Even though the ad-hoc network architecture is expected to solve this problem, but the nature of a dynamic topology makes this routing hard to be realized. This paper introduces a new ad-hoc routing algorithm, which is inspired by [1]. In their system, some control agents explore the network and update routing tables on their own knowledge. Using these routing tables, other agents deliver messages. They considered the feasibility of the agent-based routing system, but did not refer to an efficient algorithm. In this paper, we consider that algorithm without increasing network load. We propose multiple entries for each destination in the routing table to store much more information from agents and evaluating them to make better use of information, which succeeded in raising the network connectivity by about 40% by simulation.