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Effective call admission control (CAC) is one of the most important techniques to provide the desired quality of service (QoS) in wireless networks. This paper investigates the call admission control problem for the power-controlled CDMA systems. With a macroscopic description for the power control problem, the call admission control for the power-constrained system is analyzed and an admissibility condition is derived. Based on the derived condition, we propose two CAC algorithms. One is an interactive method that provides the optimum performance, but requires some information exchange between base stations. The other can be implemented in a distributed manner and provide a reasonable performance. Through simulations, we show that the proposed algorithms provide an improved performance.

Ad hoc wireless networks are self-generating and self-organizing networks consisting of mobile and static nodes, which are small and have limited power resources. In a typical setup, these nodes communicate with each other through wireless medium and may act as source, destination and/or relaying nodes. As the power of the remote nodes is depleted very quickly, it is important to have a renewable energy source to support the network operations and increase lifetime. The availability of energy from the environment is unpredictable, random and uncertain, therefore energy harvesting with appropriate management plays an important role in continuous operations of ad hoc networks. In this paper, an energy harvesting and management model is presented for ad hoc networks. Along with harvesting energy, the proposed model ensures the connectivity requirements of the network for its perpetual operation.

Induction heating (IH) applications aided by power electronic control system have become very attractive in the recent past. The power electronics circuits succumb to severe switching loss, lower power density if proper switching methodology is not adhered. A state of uncertainty is indispensable in IH application as the power required by the load varies depending upon the nature of work piece. This uncertain issue makes the selection of the control algorithm and controller very vital. The mundane controllers may not be compatible to combat the uncertainties and leads to exhibit dynamic problems say transients, peak overshoot and poor response. Henceforth, the IH system requires a superlative converter topology and control scheme in order to have reduced switching loss and to improve the system performance there by negating the uncertainties. Here, in this work, a direct AC–AC boost resonant converter fed by pulse density modulation (PDM) is realized in a single stage mode. A fuzzy logic-based PDM control technique improves the efficiency and provides the versatile power control with reduced time domain specifications for dynamic changes in load. The proposed system has been studied using MATLAB/SIMULINK and validated using a hardware prototype employing dsPIC30F4011 microcontroller. The results reveal that efficient control over power can be accomplished by varying the density of the switching pulses, and thereby the efficiency is enhanced even with reduced component count. Also, the single-stage conversion is effective than its two-stage counterpart.