On the energy efficiency of LT codes in proactive Wireless Sensor Networks

This paper presents the first analysis on the energy efficiency of LT codes with Non-Coherent M-ary Frequency Shift Keying (NC-MFSK), known as green modulation, in a proactive Wireless Sensor Network (WSN) over Rayleigh flat-fading channels with path-loss. The current analysis is based on realistic parameters in the IEEE 802.15.4 standard including the effect of channel bandwidth and active mode duration. We also present the first study on the LT code rate and coding gain characteristics achieving a given Bit Error Rate (BER), and their effects on the total energy consumption for different transmission distances d. Experimental results show that among various channel coding schemes, the optimized LT coded NC-MFSK is the most energy-efficient scheme for distance d greater than the pre-determined threshold level d_T, where the optimization is performed over coding and modulation parameters. While for d<;d_T, uncoded NC-MFSK outperforms coded schemes.