LT codes based distributed coding for efficient distributed storage in Wireless Sensor Networks

Abstract

Fountain codes are linear codes with low complexities. LT (Luby Transform) codes, which are a special class of Fountain codes, are widely used in Wireless Sensor Networks (WSNs) to increase the robustness of data storage and efficiency of data retrieval. In this paper, we propose a novel LT codes based Distributed Coding (LTDC) scheme for efficient distributed storage in WSNs. In the proposed LTDC scheme, we use random walks to disseminate sensed data from a source sensor node to a random subset of sensor nodes by multicast. As long as a data packet stops at an ending sensor node of a random walk, the ending sensor node encodes this data packet in a main packet (an encoded data packet) with a certain probability. By adjusting the main packet with the un-encoded data packets, the number of data packets encoded in the main packet follows the distribution of LT codes. The data collector is able to decode the original data by querying any subset of sensor nodes. The theoretical analysis and simulation results have demonstrated that the proposed LTDC scheme has lower data dissemination cost and lower storage overhead, while maintains the same level of fault tolerance as the original LT codes.