Resource Allocation in Wireless Powered Cognitive Radio Networks Based on a Practical Non-Linear Energy Harvesting Model

Wireless powered techniques have been recognized as promising techniques in future wireless communication systems, especially in cognitive radios (CRs) with energy-limit devices. However, most of the existing works focus on CRs with an ideal linear energy harvesting model. In this paper, a wireless powered wideband CR network is considered, and a practical non-linear energy harvesting model is adopted. To maximize the sum throughput of the secondary users, the energy harvesting time, channel allocation, and transmit power are jointly optimized. The closed-form expressions for the optimal transmit power and channel allocation are given. Simulation results show that there is a tradeoff between the harvesting energy and the sum throughput of the secondary users. It is also shown that the performance achieved under the non-linear energy harvesting model may equal to that achieved under the linear energy harvesting model.

无线供电技术已被认为是未来无线通信系统中很有前景的技术，特别是在具有能量受限设备的认知无线电（CR）中。然而，现有的大多数研究都集中在具有理想线性能量收集模型的认知无线电上。在本文中，考虑了一个无线供电的宽带认知无线电网络，并采用了一个实际的非线性能量收集模型。为了使次用户的总吞吐量最大化，对能量收集时间、信道分配和发射功率进行了联合优化。给出了最优发射功率和信道分配的闭式表达式。仿真结果表明，在收集的能量和次用户的总吞吐量之间存在一种权衡。还表明在非线性能量收集模型下取得的性能可能与在线性能量收集模型下取得的性能相同。