Data Gathering in a Hybrid Wireless Sensor Network

In recent years, wireless sensor networks are widely used in various applications. This paper proposes a data gathering protocol with mobile relays to solve the partition problem of sensor network. When some sensor nodes have exhausted their batteries or are failure, some holes occur in the network topology. Because of the existence and enlargement of the holes, the sensor network is partitioned into several sub-networks. A sink is deployed to collect data from the sensor network. But the sink cannot receive the data from the whole network while holes exist, because the holes block the communication between the sub-networks. The data of sub-networks cannot be delivered to the sink. Our data gathering protocol dispatches mobile relays to collect the data of partition networks. By the mobile relays, the sink can continuously receive data from partition networks to increase data delivery ratio. The simulation results show that the proposed data gathering protocol can collect more data from the partitioned wireless sensor network and extend the network lifetime by mobile relays. In addition, this protocol also increases the success ratio of packet delivery.