Adaptive Parallel Concatenation Turbo Codes for Wireless Sensor Networks

Abstract

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. In some applications, wireless channels between nodes are prone to high noise and interference, where Automatic Repeat Request (ARQ) techniques are inefficient for the power loss in packets retransmissions. Error Correcting Codes (ECC) can be used to reduce the number of retransmissions. The high processing power and processing time of ECC powerful decoders make it unsuitable to be implemented in sensor nodes. Simple ECC techniques come with high redundancy in the transmitted packets and low correction ability. In this paper we present a powerful ECC technique for sensor networks based on Parallel Concatenation Turbo Codes. The soft-decision iterative decoder is implemented at the base station and a low power turbo encoder and error correction circuit are implemented at the sensor nodes. This approach enhances the reliability of the network communications, while being energy- and delay efficient. We also tested effect of increasing number of communication hops and variant interleaver memory sizes.