Wireless sensor networks with joint network-channel code optimization

Optimization of large sensor network architecture in order to improve the overall system performance at the end processing station is an important challenge. Many architectures have been designed to optimize the bit error rate. Conventionally, this optimization is performed by inserting relays between sensors and destination. These relays insert redundant information by mixing the incoming streams from sensor nodes hence creating parity check information which is very useful to help decode the transmit information from sensors. The goal is to combine network and channel coding to match network on graph to code on graph, and this is called adaptive network coded cooperation. Compared with the previous works in the field, we propose a new transmit protocol based on the use of beamforming technique, which is very efficient in terms of throughput and is fully compatible with the physical network coding (PNC) principles. Furthermore, we propose a distributed coding scheme where the relay, the destination, and the sensors are all equipped with repeat accumulate (RA) channel code structures. The relay has a special RA structure to suit the need of the PNC multiple-access channel. Copyright (C) 2013 John Wiley & Sons, Ltd.