Wireless Sensor Networks, Energy Efficient Routing Protocol Design

With the rapid development in MEMS-based sensor technology, embedded computing and low-power wireless communications, wireless sensor networks (WSNs) have become a very hot research topic. Since sensor nodes have stringent limitations on energy, computation, communication and memory capabilities, how to save the energy of the sensors in order to prolong the lifetime of the whole network is a challenging issue. Routing is one of the most important functions in WSNs. In this paper, we focus on designing energy-efficient routing protocols in large-scale WSNs.This paper firstly proposes a March Inspired Geographic (MIG) routing protocol for "many to one" communications in wireless sensor networks, MIG for short. In this protocol, a data packet can avoid meeting a "hole" in advance instead of bypassing a hole when it meets the hole as existing Non-Bypass In Advanceprotocols (NBIA) do. We prove that the proposed protocol can always find a routing path between a given source node and the sink if such a routing path does exist in the network. Simulation studies show that the proposed protocol constructs routing paths with shorter routing distance and less energy consumption in comparison with the existing NBIA protocols.This paper then proposes "A Local Location Update-based routing Protocol in WSNs", ALLUP for short. When the sink node moves, it only needs to broadcast its location information within a local area rather than among the whole network. Both theoretical analysis and simulation studies show that it consumed less energy and decreased the collisions in wireless transmissions, which can be used in large-scale WSNs.This paper further proposes HashQuery, a hash-area-based data dissemination protocol in WSNs. In this protocol, both mobile sinks and sensors can determine the same hash-area computed with a hash function which uses the time as the keyword. The sensors can send the information about the events that they monitored to that area and the mobile sinks need only to query that area instead of flooding among the whole network, and thus much energy can be saved. In addition, the location of the hash area will change over time so as to balance the energy consumption in the whole network. Both theoretical analysis and simulation studies show that the proposed protocol can save much more energy compared with the existing TTDD protocol, especially in the large-scale WSNs.Considering the characteristics of sensor networks, this paper proposes several novel routing protocols, which show that with the proper routing protocol the energy of the network can be greatly saved so the lifetime of networks can be prolonged.