Optimization of OFDMA upstream schedule for IEEE 802.22 wireless regional area networks

This paper presents a method for optimizing OFDMA upstream scheduling in event monitoring applications related to IEEE 802.22 wireless regional area networks (WRANs). Upstream scheduling optimization is a trade-off between management transmission and data transmission in a frame. We provide analytical models to derive an optimum upstream schedule that maximizes the network performance in terms of network energy consumption and network throughput. Interestingly, the energy consumption decreases with an increase in the management transmission portion, whereas the maximum throughput is obtained at a specific management transmission portion. Moreover, the upstream schedule that minimizes the energy consumption may not provide the maximum network throughput, and vice versa. For investigating the optimal upstream schedule, we generalize the energy consumption over the throughput that indicates the energy consumed to achieve a unit of throughput. On the basis of the generalization, we find an optimal upstream ratio of the management transmission portion and the data transmission portion. Our study provides a useful solution to design the OFDMA upstream scheduler and to optimize the performance of the IEEE 802.22 WRANs.