Diverse-Rate Based Dual Energy Aware Efficiency Task Scheduling Scheme in WSNs

It is important to increase the wireless sensor networks (WSNs) lifetime and the ability of energy conservation, due to its limited energy resource, while meeting the constraints of applications. In this paper, we concern the protocol and OS task schedule perspective to enhance the performance of WSNs. Firstly we propose a diverse-rate based upon pre-schedule schedule to further decrease collisions and enhance the operating factor of energy in CSMA/TDMA hybrid MAC layer of wireless sensor network. Our method combines CSMA and TDMA functionalities. We concern the protocol assignment by the pre-schedule slot. During the pre-schedule slot, each node knows exactly the schedule of other neighbor nodes. Diverse-rate and power scaling are applied to achieve further energy saving by adopting an acceptable rate rather than maximum rate. Data rate is dynamically adjusted according to the traffic load of sending nodes, in an energy efficient data rate, to save energy. Local framing pre-schedule and diverse-rate in this experiment achieved further energy efficiency. Secondly, from task schedule perspective, we present a voltage and sleep dual-effective scheduling algorithm in terms of dynamic energy management and dynamic voltage/frequency scaling, namely, DV/FS2 RM and DV/FS2 EDF. On the preface of guarantee node real time performance, the policy can not only dynamically control idle task to enter sleep mode but also reduce sensor working frequency to obtain better power conservation effect through DV/FS2 RM or DV/FS2-EDF algorithm. Experiments show that the effect of the energy conversation task scheduling algorithm is remarkable which can expands the lifetime of wireless sensor network node several times which mainly depend on batteries power supply.