On the Energy Efficiency of WSN Communications Operating Under Non-coherent M-FSK and M-QAM Modulations

摘要

To make Wireless Sensor Network (WSN) market growth a reality, we need to empower the network designers with a provision to optimally tailor the physical layer parameters. In this paper, we present a holistic analysis of energy related aspects of WSN communications operating under Rayleigh fading, using standardized WSN specifications. The rational expressions have been derived by taking into consideration the effects of packet size, repeated training sequences, transmission distance, path-loss, amplifier efficiency, bandwidth of the channel and active mode span for Non-coherent M-ary FSK (NC-MFSK) and M-QAM modulation schemes. The results of variation of total energy consumption along with various parameters like path-loss, amplifier efficiency, hop distance and packet size have been investigated. We found that for small transmission distances, M-QAM modulation performs better than NC-MFSK scheme, but as the distance increases the NC-MFSK outperforms the M-QAM in the terms of energy efficiency. Moreover, for communications operating with NC-MFSK modulation, the crossover point of better energy efficiency is achieved at lesser distance with increase in value of path-loss parameter. These results may enable the network designers to plan energy-efficient WSN communication architectures even in the presence of constrained environments.