An energy-efficient and low latency (E2L2) MAC protocol for low traffic wireless sensor networks

Medium Access Control (MAC) protocols are application specific in nature. This paper proposes E²L² MAC protocol for applications involving low network traffic but requiring prompt delivery of data. The wireless sensor networks´ application area of medical monitoring and treatment is an example which encompasses such characteristics and requirements. Sensor nodes operate in half duplex mode and are defined to have two communication channels- data and control channel. While handshakes, to avoid collision between the contending sensor nodes, are done on the control channel using modified RTS and CTS packets, the data channel is utilized for data transmission. Low traffic on the network allows node reservation chain to be formed with the help of control channel handshakes, at the same time when data is flowing on the data channel. A packet reception algorithm is utilized to decide on the type of scheduling behavior to be used by the sensor nodes. Significant advantages in energy efficiency and latency are obtained as a direct impact of the protocol.