Joint Design of Clustering and In-cluster Data Route for Heterogeneous Wireless Sensor Networks

A heterogeneous wireless sensor network comprises a number of inexpensive energy constrained wireless sensor nodes which collect data from the sensing environment and transmit them toward the improved cluster head in a coordinated way. Employing clustering techniques in such networks can achieve balanced energy consumption of member nodes and prolong the network lifetimes.In classical clustering techniques, clustering and in-cluster data routes are usually separated into independent operations. Although separate considerations of these two issues simplify the system design, it is often the non-optimal lifetime expectancy for wireless sensor networks. This paper proposes an integral framework that integrates these two correlated items in an interactive entirety. For that,we develop the clustering problems using nonlinear programming. Evolution process of clustering is provided in simulations. Results show that our joint-design proposal reaches the near optimal match between member nodes and cluster heads.

Vector Segment Routing for Large-Scale Multilayer Satellite Network

With the expansion of satellite constellation,routing techniques for small-scale satellite networks have problems in routing overhead and forwarding efficiency.This paper proposes a vector segment routing method for large-scale multi layer satellite networks.A vector forwarding path is built based on the location between the source and the destination.Data packets are forwarded along this vector path,shielding the influence of satellite motion on routing forwarding.Then,a dynamic route maintenance strategy is suggested.In a multi layer satellite network,the low-orbit satellites are in charge of computing the routing tables for one area,and the routing paths are dynamically adjusted in the area in accordance with the network.The medium-orbit satellites maintain the connectivity of vector paths in multiple segmented areas.The forwarding mode based on the source and destination location improves the forwarding efficiency,and the segmented route maintenance mode decreases the routing overhead.The simulation results indicate that vector segment routing has significant performance advantages in end-to-end delay,packet loss rate,and throughput in a multi layer satellite network.We also simulate the impact of routing table update mechanism on network performance and overhead and give the performance of segmented vector routing in multi layer low-orbit satellite networks.