CMNS: An Energy-Efficient Communication Scheme for Wireless Sensor Networks

Abstract

A new technique for energy-efficient communication in wireless sensor networks is proposed here which is based on a novel source coding of multiple sensor data coupled with the use of silent communication strategy. The source coding technique exploits high temporal correlation between sensor data by first appropriately interleaving the bits of two consecutive sensor data values and then representing every two consecutive bits of this interleaved dual message by one of four symbol values so that the overall message length is reduced by a factor of two. After that, any occurrence of the same symbol value in consecutive positions of this string is replaced by a null symbol. The transmitter is kept silent during the periods of these null symbols following the strategy of silent communication to save transmitter energy. We propose a hybrid modulation / demodulation technique using non-coherent frequency-shift keying (FSK) and amplitude-shift keying (ASK) to implement this communication scheme, termed as Compression with Multiple Null Symbols (CMNS). From simulation results with various real-life sensor data, we find that CMNS provides transmitter energy savings ranging from 73.16% to 46.6% and receiver energy saving of 50% over conventional BFSK. When compared with other existing schemes, we see from simulation with all these sensor data sets that CMNS provides an improvement over Quint Fibonacci Number System (QFNS), the best known similar scheme, in transmitter energy savings ranging from 9.96% to 113.46% and an improvement in receiver energy savings ranging from 4.85% to 27.94%. These results establish that our proposed scheme is very suitable for multihop communication in low cost wireless sensor network applications.