Hoan Tran-Nhut-Khai, Hiep Vu-Van, Koo In-Soo
The School of Electrical Engineering, University of Ulsan, Ulsan 680-749, Korea.
Sensors (Basel). 2016 Mar 31;16(4):461. doi: 10.3390/s16040461.
This paper considers cognitive radio networks (CRNs) utilizing multiple time-slotted primary channels in which cognitive users (CUs) are powered by energy harvesters. The CUs are under the consideration that hardware constraints on radio devices only allow them to sense and transmit on one channel at a time. For a scenario where the arrival of harvested energy packets and the battery capacity are finite, we propose a scheme to optimize (i) the channel-sensing schedule (consisting of finding the optimal action (silent or active) and sensing order of channels) and (ii) the optimal transmission energy set corresponding to the channels in the sensing order for the operation of the CU in order to maximize the expected throughput of the CRN over multiple time slots. Frequency-switching delay, energy-switching cost, correlation in spectrum occupancy across time and frequency and errors in spectrum sensing are also considered in this work. The performance of the proposed scheme is evaluated via simulation. The simulation results show that the throughput of the proposed scheme is greatly improved, in comparison to related schemes in the literature. The collision ratio on the primary channels is also investigated.
本文考虑了认知无线电网络（CRN），其中认知用户（CU）由能量收集器供电，并利用多个时隙主信道。考虑到无线电设备的硬件限制只允许CU一次在一个信道上进行感知和传输。对于收集到的能量包到达量和电池容量均有限的场景，我们提出一种方案来优化：（i）信道感知调度（包括找到最优动作（静默或活跃）以及信道的感知顺序）；（ii）与感知顺序中的信道相对应的最优传输能量集，以使CU在多个时隙内运行时CRN的预期吞吐量最大化。本研究还考虑了频率切换延迟、能量切换成本、频谱占用在时间和频率上的相关性以及频谱感知中的误差。通过仿真评估了所提方案的性能。仿真结果表明，与文献中的相关方案相比，所提方案的吞吐量有显著提高。同时还研究了主信道上的冲突率。
