Modulation scaling for energy efficiency
Résumé
The energy consumption of wireless communicating devices as well as their autonomy are two important
factors in energy constrained system such asWireless Sensor Networks (WSNs). The spectral efficiency is another important
metric. The main goal is to study the trade-off between the energy consumption of the systemand it’s spectral efficiency
when varying system parameters. In this paper, an uncoded system using M-ary Quadrature Amplitude Modulation
(M-QAM) in which the spectral efficiency is assumed proportional to its bandwidth efficiency is used. In order to find
the balance between spectral and energy requirements, the considered system parameters are studied. First, a general
and comprehensive power model for both transmitter and receiver is developed. Next, by considering Additive White
Gaussian Noise (AWGN) channel for point-to-point communication, the total energy consumption is evaluated. A new
approximation for the Bit Error Rate (BER) is adopted. Then, the effect of communication distance, bandwidth and circuit
power consumption on the optimum spectral efficiency is studied. For a fixed BER, we demonstrate that for each of those
parameters, an optimumspectral efficiency can be found.