Low power channel coding for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) consist of a set of small devices with limited energy resources, reduced processing capabilities and a radio frequency communication unit with limited transmission power. Transmission over the wireless channels is prone to noise and interference which causes the reception of erroneous packets at the receiving node. Automatic Repeat Request (ARQ) techniques are usually used in WSNs to tackle erroneous transmission, but they become inefficient (with respect to energy and delay) in harsh environments. To reduce the number of retransmission for lossy channels, Error Correcting Codes (ECC) are commonly used. The use of ECC comes with increased processor power and delay at the sensor nodes for encoding and decoding the packets. In this work we present an ECC technique for sensor networks based on Turbo Codes. A low complexity turbo encoder is deployed at the source nodes, while the iterative decoding process is shifted to the Base Station. The forwarding nodes contribute by executing error monitoring and correcting. This approach enhances the reliability of the network communications, while being energy- and delay efficient.