Enabling Wireless Power Transfer in Cellular Networks: Architecture, Modeling and Deployment

Abstract

Microwave power transfer (MPT) delivers energy wirelessly from stations called power beacons (PBs) to mobile devices by microwave radiation. This provides mobiles practically infinite battery lives and eliminates the need of power cords and chargers. To enable MPT for mobile charging, this paper proposes a new network architecture that overlays an uplink cellular network with randomly deployed PBs for powering mobiles, called a hybrid network. The deployment of the hybrid network under an outage constraint on data links is investigated based on a stochastic-geometry model where single-antenna base stations (BSs) and PBs form independent homogeneous Poisson point processes (PPPs) with densities λ b and λ p , respectively, and single-antenna mobiles are uniformly distributed in Voronoi cells generated by BSs. In this model, mobiles and PBs fix their transmission power at p and q, respectively; a PB either radiates isotropically, called isotropic MPT, or directs energy towards target mobiles by beamforming, called directed MPT. The model is applied to derive the tradeoffs between the network parameters (p, λ b , q, λ p ) under the outage constraint. First, consider the deployment of the cellular network. It is proved that the outage constraint is satisfied so long as the product pλ α 2 b is above a given threshold where α is the path-loss exponent. Next, consider the deployment of the hybrid network assuming infinite energy storage at mobiles. It is shown that for isotropic MPT, the product qλ p λ α 2 b has to be above a given threshold so that PBs are sufficiently dense; for directed MPT, z m qλ p λ α 2 b with z m denoting the array gain should exceed a different threshold to ensure short distances between PBs and their target mobiles.Furthermore, for directed MPT, (z m q) 2 α λ b has to be sufficiently large as otherwise PBs fail to deliver sufficient power to target mobiles regardless of power-transfer distances. Last, similar results are derived for the case of mobiles having small energy storage.

Connectivity Analysis in Clustered Wireless Sensor Networks Powered by Solar Energy

“…Furthermore, WEH-enabled large-scale networks have gained a lot of attention lately [12], [19]- [21]. Many of these works, i.e., [19], [20], discuss various network metrics, e.g., spatial throughput and coverage, but not the probability of connectivity, which guarantees the reliability of safety-critical applications.…”

“…In this way, the devices are free to move or even be embedded in walls or human bodies without affecting extensively their ability to replenish their energy. To increase and control the provided wireless energy, dedicated power transmitters or power beacons (PBs) that supply RF energy to the sensors are distributed in the deployment area [12]. Moreover, due to the involvement of a potentially large number of wireless sensors in mMTC and cMTC applications, equipping them with batteries requires high maintenance costs as a result of the inconvenient traditional methods to replenish their energy (i.e., battery replacement or cable-charging).…”

“…Similarly, although works on the allocation of solar harvested energy [17], [18] manage to prevent power outages in the network, they assume that the communication performance remains unaffected by the changes in the energy intake during the network operation. Furthermore, there are several works on large-scale WEH-enabled networks [12], [19]- [21], but: i) they do not study the network connectivity, which is crucial to ensure that all nodes are able to deliver their messages, and ii) they assume that the network devices, i.e., GWs or PBs, are connected to the electricity grid.…”

Multiple Sensor based Channel Estimation and Beamforming Mechanism for Wireless Powered Sensor Network

“…During the past decade, with the development in RF energy harvesting circuit, low power transfer for powering mobile terminals in wireless communication systems began to attract increasing attention. The authors in [7] propose network architecture for RF charging stations, overlaying with an uplink cellular network. A harvestthen-transmit protocol is introduced for power transfer in wireless broadcast system.…”

Impact of primary networks on the performance of energy harvesting cognitive radio networks

“…Furthermore, users' energy consumption will be continuously reduced by the advancements in low-power electronics [8]. Therefore, RF EH has a great potential to be widely implemented in the next-generation wireless communication systems.…”