A LT-Codes-Based Scheme for Improving Data Persistence in Wireless Sensor Networks

For a wireless sensor network that does not has a fixed sink and is deployed in Hash environment, each node should disseminate its data to a subset of nodes in the network for storage. By this way, a mobile sink can collect all data even if some nodes die due to accident. A novel LT(Luby transform)-codes-based scheme, named LTSIDP, is proposed, where LT codes are a kind of erasure codes. In LTSIDP, the process of data storage is divided into two steps. In the first step, nodes estimate the number of nodes in the network and the number of data packets by receiving packets for some time. After they acquire the numbers, they can compute a parameter of LT codes. In the second step, nodes store the data they received according to the parameter. After LTSIDP terminates at each round, when a mobile sink enters the network at anytime and anywhere in a given interval, it can collect all data even if it just visits a small number of alive nodes. Theoretical analysis and experiments show that LTSIDP can not only achieve higher data persistence but also has more energy efficiency than previous schemes.