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Wireless Ad Hoc and Sensor Networks

Wireless Ad Hoc and Sensor Networks

Wireless Ad Hoc and Sensor Networks

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476 <strong>Wireless</strong> <strong>Ad</strong> <strong>Hoc</strong> <strong>and</strong> <strong>Sensor</strong> <strong>Networks</strong>not attempt to provide the interference-based adaptive distribution tuningscheme for the PPC. We only implement PPC using fixed power distributionsfor all scenarios to observe the overall performance patterns <strong>and</strong>to underst<strong>and</strong> the differences between the DAPC <strong>and</strong> PPC. The twodistributions, Beta(0.1, 0.1) <strong>and</strong> Beta(2, 2) used in Figure 10.4 are chosenfor the simulation <strong>and</strong> compared for performance evaluation.In terms of implementation, PPC only requires a power control blockthat selects output power based on predefined probability distributions.However, a more complex model of PPC can be generated provided therelationship in Equation 10.31 can be obtained. This PPC requires interferencemeasurement <strong>and</strong> dynamically adjusts the power distributionbased on interference to maximize µ r <strong>and</strong> ρ .10.5 Simulation ResultsThe simulation environment is set up in MATLAB. Full model of DAPC<strong>and</strong> PPC are implemented for comparison. Both algorithms are testedunder the same configuration.10.5.1 Reader DesignReader power is implemented as a floating point number varying from0 to 30 dBm (1 W) as per FCC regulations. For error-free detection, thereader should maintain a target SNR of 14 (~11 dB). Other system constantsare designed so that the maximum read range of a reader in anisolated environment is 3 m. Interference experienced at any reader iscalculated based on a matrix consisting of power <strong>and</strong> positions of all otherreaders plus the channel variation g ij . A desired range of 2 m is specifiedbased on the worst case analysis.For the proposed DAPC, power update parameters Kv <strong>and</strong> s are bothset to 0.001. For proposed PPC, both Beta(0.1, 0.1) <strong>and</strong> Beta(2, 2) areimplemented.10.5.2 Simulation ParametersFor both models, r<strong>and</strong>om topologies are generated in order to emulatedenser networks with a suitable number of readers. The RFID networkwith a suitable density for a given scenario is created by placing thereaders with the minimum distance between them <strong>and</strong> the maximum areaunder test. The minimum distance between any two readers is varied

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