Wireless Information and Power Transfer: A Dynamic Power Splitting Approach
Wireless Information and Power Transfer: A Dynamic Power Splitting Approach
复制标题
DOI：
10.1109/tcomm.2013.071813.130105
复制
发表时间：
2013-09-01
影响因子：
8.3
通讯作者：
Chua, Kee-Chaing
中科院分区：
文献类型：
--
作者：
Liu, Liang;Zhang, Rui;Chua, Kee-Chaing
能量收集是延长能量受限无线网络运行时间的一种有前景的解决方案。特别是从周围无线电信号中获取能量，即无线能量收集（WEH），最近引起了极大的关注。在本文中，我们考虑平坦衰落信道上的点对点无线链路，其中接收端没有固定电源，因此需要通过从发射端发送的信号进行无线能量收集来补充能量。
我们首先考虑一个单输入单输出（SISO）系统，其中单天线接收端无法从接收到的同一信号中独立地解码信息和收集能量。在这种实际约束条件下，我们提出一种动态功率分配（DPS）方案，根据接收端已知的瞬时信道状况，将接收到的信号分成具有可调节功率水平的两个流，分别用于信息解码和能量收集。我们推导出接收端的最优功率分配规则，以在信息传输的最大遍历容量和功率传输的最大平均收集能量之间实现各种权衡，这些权衡由所谓的“速率 - 能量（R - E）”区域的边界来表征。
此外，对于发射端也知道信道状态信息的情况，我们研究发射端功率控制和接收端功率分配的联合优化。我们还将所提出的DPS方案可实现的R - E区域与现有的时间切换方案以及忽略实际接收端约束的性能上界进行比较。
最后，我们将最优DPS的结果扩展到接收端配备多根天线的单输入多输出（SIMO）系统。特别是，我们研究一种低复杂度的功率分配方案，即天线切换，与最优DPS相比，它实现了接近最优的速率 - 能量权衡。
Energy harvesting is a promising solution to prolong the operation time of energy-constrained wireless networks. In particular, scavenging energy from ambient radio signals, namely wireless energy harvesting (WEH), has recently drawn significant attention. In this paper, we consider a point-to-point wireless link over the flat-fading channel, where the receiver has no fixed power supplies and thus needs to replenish energy via WEH from the signals sent by the transmitter. We first consider a SISO (single-input single-output) system where the single-antenna receiver cannot decode information and harvest energy independently from the same signal received. Under this practical constraint, we propose a dynamic power splitting (DPS) scheme, where the received signal is split into two streams with adjustable power levels for information decoding and energy harvesting separately based on the instantaneous channel condition that is assumed to be known at the receiver. We derive the optimal power splitting rule at the receiver to achieve various trade-offs between the maximum ergodic capacity for information transfer and the maximum average harvested energy for power transfer, which are characterized by the boundary of a so-called "rate-energy (R-E)" region. Moreover, for the case when the channel state information is also known at the transmitter, we investigate the joint optimization of transmitter power control and receiver power splitting. The achievable R-E region by the proposed DPS scheme is also compared against that by the existing time switching scheme as well as a performance upper bound by ignoring the practical receiver constraint. Finally, we extend the result for optimal DPS to the SIMO (single-input multiple-output) system where the receiver is equipped with multiple antennas. In particular, we investigate a low-complexity power splitting scheme, namely antenna switching, which achieves the near-optimal rate-energy trade-offs as compared to the optimal DPS.