A Novel Protocol in Intermittent Connected Mobile Networks

Intermittent connected mobile sensor networks (ICMSN) have emerged in recent studies, e.g. underwater sensor networks, wildlife tracking and human-oriented flu virus monitoring. In these networks, there are no end to end connections from sensor nodes to sink nodes due to low node density and node mobility. Therefore, conventional routing protocols in WSN are not practical for ICMSN since packets will be dropped when no complete route to the sink is available. In this paper, we propose an efficient routing protocol for ICMSN, which is composed of buffer management and message forwarding. Buffer management consists of two related components: queuing mechanism and purging mechanism. The former determines priority of messages to transmit or discard based on the importance factor, which indicates the QoS requirement of the messages. The latter utilizes a death vector generated by the sink to purge useless messages that have been delivered from the network. Message forwarding makes decision on which sensors are qualified for next hop based on node delivery probability, which synthesizes the meeting predictability to the sink, current buffer state and residual energy and increases the likelihood that the sensor can deliver the message to the sink. Our experimental results show that the proposed routing protocol not only supports the QoS requirement of different content but also achieves the good performance tradeoff between delivery ratio, delay and resource consumption.