Optimized Training Design for Wireless Energy Transfer
- 22 December 2014
- journal article
- research article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Communications
- Vol. 63 (2), 536-550
- https://doi.org/10.1109/tcomm.2014.2385077
Abstract
Radio-frequency (RF) enabled wireless energy transfer (WET), as a promising solution to provide cost-effective and reliable power supplies for energy-constrained wireless networks, has drawn growing interests recently. To overcome the significant propagation loss over distance, employing multi-antennas at the energy transmitter (ET) to more efficiently direct wireless energy to desired energy receivers (ERs), termed energy beamforming, is an essential technique for enabling WET. However, the achievable gain of energy beamforming crucially depends on the available channel state information (CSI) at the ET, which needs to be acquired practically. In this paper, we study the design of an efficient channel acquisition method for a point-to-point multiple-input multiple-output (MIMO) WET system by exploiting the channel reciprocity, i.e., the ET estimates the CSI via dedicated reverse-link training from the ER. Considering the limited energy availability at the ER, the training strategy should be carefully designed so that the channel can be estimated with sufficient accuracy, and yet without consuming excessive energy at the ER. To this end, we propose to maximize the net harvested energy at the ER, which is the average harvested energy offset by that used for channel training. An optimization problem is formulated for the training design over MIMO Rician fading channels, including the subset of ER antennas to be trained, as well as the training time and power allocated. Closed-form solutions are obtained for some special scenarios, based on which useful insights are drawn on when training should be employed to improve the net transferred energy in MIMO WET systems.Keywords
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Funding Information
- National University of Singapore (R-263-000-679-133)
This publication has 34 references indexed in Scilit:
- Dynamic spectrum access in cognitive radio networks with RF energy harvestingIEEE Wireless Communications, 2014
- Power Allocation Strategies in Energy Harvesting Wireless Cooperative NetworksIEEE Transactions on Wireless Communications, 2014
- Wireless Information and Power Transfer: Architecture Design and Rate-Energy TradeoffIEEE Transactions on Communications, 2013
- Relaying Protocols for Wireless Energy Harvesting and Information ProcessingIEEE Transactions on Wireless Communications, 2013
- Ordered Eigenvalues of a General Class of Hermitian Random Matrices With Application to the Performance Analysis of MIMO SystemsIEEE Transactions on Signal Processing, 2008
- Simplified Spatial Correlation Models for Clustered MIMO Channels With Different Array ConfigurationsIEEE Transactions on Vehicular Technology, 2007
- Closed-Form Expressions for the Outage and Ergodic Shannon Capacity of MIMO MRC SystemsIEEE Transactions on Communications, 2005
- Transmit Signal Design for Optimal Estimation of Correlated MIMO ChannelsIEEE Transactions on Signal Processing, 2004
- Analysis of transmit-receive diversity in rayleigh fadingIEEE Transactions on Communications, 2003
- How much training is needed in multiple-antenna wireless links?IEEE Transactions on Information Theory, 2003