Wireless Multihop Transmission with Buffering in Neighbor Sensor Nodes for Shorter Delay

In wireless multihop transmission of sensor data, in addition to avoidance of contentions and collisions of wireless signals, available capacity of communication buffers in sensor nodes should be considered. If a communication buffer in a next-hop wireless sensor node is filled, it is impossible for a wireless sensor node to forward a message with sensor data to the next-hop one. Here, the sensor node stores the message to its communication buffer and waits for the buffer in the next-hop sensor node to have enough space. The buffered messages are required to be transmitted to a sink node as soon as possible. This paper proposes a method to store the messages not only into communication buffers in wireless sensor nodes along the multihop transmission route but also in wireless sensor nodes neighboring to the multihop transmission route. By applying this method, messages with sensor data are stored into communication buffers of wireless sensor nodes nearer to the sink node and shorter end-to-end transmission delay is required. We design a routing protocol and a message transmission protocol for implementation and evaluate time duration required to transmit all buffered messages to a destination sink node by comparing with the conventional multihop transmission protocol.