Improvement of geographic energy perception routing in wireless sensor networks (1)

A wireless sensor network is a multi-hop self-organizing network system formed by a large number of low-cost micro-sensor nodes deployed in the monitoring area through wireless communication, the purpose is to collaboratively perceive, collect, and process event information in the coverage area and send it to the observer. Due to limited node energy and difficult to supplement, the primary design goal of wireless sensor networks is the efficient use of energy [6. This article proposes an improvement method based on the original GEAR [1] routing protocol to save the limited energy of wireless sensor nodes on the Routing Protocol [4] and improve the entire network life cycle.

GEAR protocol introduction and improvement

GEAR [5] (Geographical and Energy Aware Routing) Routing protocol is based on the Geographical location information of the event region, the optimal path from the aggregation node to the event region is established, avoiding pan-flood query messages, this reduces the overhead of creating a route. However, due to the lack of sufficient topology information, the traditional GEAR routing mechanism may encounter routing holes [2] During routing.

This paper proposes a Routing Mechanism Based on Two-hop node information, which greatly reduces the probability of routing holes and the average energy consumption for each successful query. Based on the relationship between the wireless transmit power and the communication radius, the transmit power is determined by the communication distance [3]. Considering the transmit power during route selection, a GPEAR routing mechanism that saves more energy is proposed.

GEAHAR Routing Mechanism

Excessive routing holes consume a lot of unnecessary energy and reduce the communication efficiency of the entire network. To reduce or avoid routing holes, nodes need to know more topology information, which is the basis proposed by GEAHAR (Geographical energy aware and hole avoid routing) mechanism. The basic idea is that when querying a message, selecting the next hop node for a node not only considers the minimum value of the neighbor hop node, but also considers the information of Two hops.

A neighbor node is a set of all nodes that can be reached within the hop communication range of a node. For example, as defined in (1), dmax is the maximum communication distance between nodes and the set of all nodes.

NbNi =

≤Dmax, Nj ε N} (1)

Node Ni selects the next Nnext (I) based on the formula (2. Nbi is the set of neighbor nodes of node Ni, and NbNbi (j) is the set of neighbor nodes of node Nbi (j) of node Ni. Beta is the proportional coefficient, and the value range is 0 ~ 1. If the value of β is 1, the algorithm degrades to a hop GEAR routing mechanism. You must note that NbNbi (j) (k) =ni, that is, the current node cannot be selected for the second hop node; otherwise, the routing is returned, this will consume a lot of unnecessary energy.

Nnext (I) = min (β c (Nbi (j), T) + (1-β) min (c (NBNbj (j) (k), T ))) nbi (j) ε Nbi, NbNbi (j) (K) ε NbNbi (j), NbNb (j) (k) ≈ Ni (2)

GPEAR Routing Mechanism

When the receiving sensitivity is certain, the relationship between the wireless transmit power P and the receiving radius R is P proportional to R2 ~ R5, that is, P may be much larger than R2. If the communication distance is considered during inter-node communication, the transmit power should be adjusted as appropriate, instead of using the same transmit power (in this case, only the maximum communication distance can be used for transmission ), it can greatly reduce the communication energy consumption, prolong the life of the entire network, and reduce the communication cost of each packet.

Geographical and physical energy aware routing.

Assume that the energy consumption of wireless communication is proportional to the power of the communication distance, and the transmit power is divided into five levels, as shown in table 1.

Table 1 Relationship Between transmit power and communication radius

The GPEAR Routing Mechanism selects the node with the smallest combination of the value of the neighbor node and the communication cost of sending the hop as the next hop node, as shown in formula (3:

Nnext (Ni) = (3)

In formula, Nnext (Ni) is the next hop Node Selected by node Ni; h (Ni, Nj, T) is the new generation value of node Ni through Nj to event region T; esend (Ni, Nj) is the communication cost between node Ni and node Nj, such as the normalized value in Table 1. NbNi is the neighbor node set of node Ni, and r is the proportional coefficient, value Range: 0 ~ 1.