2018/10/28 by Aamir Mahmood, M. M. Aftab Hossain, Mahmood, Aamir +5
Engineering · #Advanced MIMO Systems Optimization #PAPR reduction in OFDM #Energy Harvesting in Wireless Networks
paper · pdf · doi:10.48550/arxiv.1810.11902
In this paper, we study cross-layer optimization of low-power wireless links\nfor reliability-aware applications while considering both the constraints and\nthe non-ideal characteristics of the hardware in Internet-of-things (IoT)\ndevices. Specifically, we define an energy consumption (EC) model that captures\nthe energy cost---of transceiver circuitry, power amplifier, packet error\nstatistics, packet overhead, etc.---in delivering a useful data bit. We derive\nthe EC models for an ideal and two realistic non-linear power amplifier models.\nTo incorporate packet error statistics, we develop a simple, in the form of\nelementary functions, and accurate closed-form packet error rate (PER)\napproximation in Rayleigh block-fading. Using the EC models, we derive\nenergy-optimal yet reliability and hardware compliant conditions for limiting\nunconstrained optimal signal-to-noise ratio (SNR), and payload size. Together\nwith these conditions, we develop a semi-analytic algorithm for\nresource-constrained IoT devices to jointly optimize parameters on physical\n(modulation size, SNR) and MAC (payload size and the number of retransmissions)\nlayers in relation to link distance. Our results show that despite reliability\nconstraints, the common notion---higher M-ary QAM modulations are energy\noptimal for short-range communication---prevails, and can provide up to 180%\nlifetime extension as compared to often employed OQPSK modulation in IoT\ndevices. However, the reliability constraints reduce both their range and the\nenergy efficiency, while non-ideal traditional PA reduces the range further by\n50%, and diminishes the energy gains unless a better PA is employed.\n