Abstract：In this paper, the optimum numbers of cooperative nodes and modulation methods are analyzed to minimize the total energy consumption in a cooperative wireless sensor networks, which is power-limited. An exact closed-form expression is derived for the average BER in Rayleigh-fading channels for both BPSK and MQAM modulations, and then the energy of cooperative system is analyzed. Finally a synthetic optimization of modulation and number of cooperative nodes is presented to minimize the total energy consumption. Comparisons with the fix-rate or fix numbers of cooperative nodes systems demonstrate the significant energy saving of the synthetic optimization.
2010, Vol. 32 
