Algorithms to minimize data transfer for code update on wireless sensor network

In Wireless Sensor Networks, the preloaded program code and data on sensor nodes often need to be updated due to changes in user requirements and environmental conditions. Sensor nodes are severely restricted by energy constraints. It is especially energy consuming for sensor nodes to transfer data through wireless radios. To efficiently reprogram sensor nodes through radio, we propose an algorithm, Minimum Data transferred by Copying and Downloading (MDCD) and its extension E-MDCD, to minimize the number of bytes needed to be transferred from the host machine to the sensor nodes. Experimental results show that the E-MDCD algorithm reduces the number of bytes transferred by 93.25 % for small code change compared with the Rsync based algorithm. In average, E-MDCD can reduce 59.82 % compared with the existing the Rsync based algorithm and 16.14 % compared with the Vdelta algorithm.