Özet:

Wireless Sensor Networks (WSN) are divided into two categories as single-hop and multi-hop according to the connection states of the sensor nodes. In the single-hop WSNs, the sensor nodes communicate directly with the management unit (coordinator node). On the other hand, in multi-hop WSNs, the sensor nodes, which are out of the coverage area of the coordinator node communicate with the coordinator over other joined sensor nodes. Multi-hop WSNs preferred for complex applications where there are many sensor nodes. In such applications, connecting to the network and maintaining the continuity in the network is difficult and requires very complicated algorithms for sensor nodes. In this study, a new network-joining algorithm for multi-hop WSNs has been proposed and designed. According to the algorithm, there is a management unit which is named as coordinator node (CN) for maintaining the network connectivity and the nodes which are the members of the network sends network joining requests over a common contention-based channel for joining the network. If there is a coordinator node in the coverage area, the sensor node joins directly to the network and coordinator allocates an appropriate channel to the new node. If the channel has multiple users, it is used as time-shared. If the sensor node is out of coverage area, directly joining to the network is impossible. In this case, the sensor node sends a relay request to the other joined sensor nodes. The available sensor node responds to this relay request via handshake. The sensor node uses the relay node’s channels as shared by using time-sharing methods. Therefore, the new node joins the network from the relay node’s channel. The main goal of this algorithm is to speed up joining of sensor nodes to the networks in multi-hop WSNs. Also, another goal is maximizing the continuity of the sensor nodes in the network. Thus, the algorithm improves performance and ensures data transfer continuity of WSNs.

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