403 research outputs found
Cost minimization for fading channels with energy harvesting and conventional energy
In this paper, we investigate resource allocation strategies for a
point-to-point wireless communications system with hybrid energy sources
consisting of an energy harvester and a conventional energy source. In
particular, as an incentive to promote the use of renewable energy, we assume
that the renewable energy has a lower cost than the conventional energy. Then,
by assuming that the non-causal information of the energy arrivals and the
channel power gains are available, we minimize the total energy cost of such a
system over fading slots under a proposed outage constraint together with
the energy harvesting constraints. The outage constraint requires a minimum
fixed number of slots to be reliably decoded, and thus leads to a mixed-integer
programming formulation for the optimization problem. This constraint is
useful, for example, if an outer code is used to recover all the data bits.
Optimal linear time algorithms are obtained for two extreme cases, i.e., the
number of outage slot is or . For the general case, a lower bound
based on the linear programming relaxation, and two suboptimal algorithms are
proposed. It is shown that the proposed suboptimal algorithms exhibit only a
small gap from the lower bound. We then extend the proposed algorithms to the
multi-cycle scenario in which the outage constraint is imposed for each cycle
separately. Finally, we investigate the resource allocation strategies when
only causal information on the energy arrivals and only channel statistics is
available. It is shown that the greedy energy allocation is optimal for this
scenario.Comment: to appear in IEEE Transactions on Wireless Communication
Energy Harvesting Wireless Communications: A Review of Recent Advances
This article summarizes recent contributions in the broad area of energy
harvesting wireless communications. In particular, we provide the current state
of the art for wireless networks composed of energy harvesting nodes, starting
from the information-theoretic performance limits to transmission scheduling
policies and resource allocation, medium access and networking issues. The
emerging related area of energy transfer for self-sustaining energy harvesting
wireless networks is considered in detail covering both energy cooperation
aspects and simultaneous energy and information transfer. Various potential
models with energy harvesting nodes at different network scales are reviewed as
well as models for energy consumption at the nodes.Comment: To appear in the IEEE Journal of Selected Areas in Communications
(Special Issue: Wireless Communications Powered by Energy Harvesting and
Wireless Energy Transfer
Cognitive and Energy Harvesting-Based D2D Communication in Cellular Networks: Stochastic Geometry Modeling and Analysis
While cognitive radio enables spectrum-efficient wireless communication,
radio frequency (RF) energy harvesting from ambient interference is an enabler
for energy-efficient wireless communication. In this paper, we model and
analyze cognitive and energy harvesting-based D2D communication in cellular
networks. The cognitive D2D transmitters harvest energy from ambient
interference and use one of the channels allocated to cellular users (in uplink
or downlink), which is referred to as the D2D channel, to communicate with the
corresponding receivers. We investigate two spectrum access policies for
cellular communication in the uplink or downlink, namely, random spectrum
access (RSA) policy and prioritized spectrum access (PSA) policy. In RSA, any
of the available channels including the channel used by the D2D transmitters
can be selected randomly for cellular communication, while in PSA the D2D
channel is used only when all of the other channels are occupied. A D2D
transmitter can communicate successfully with its receiver only when it
harvests enough energy to perform channel inversion toward the receiver, the
D2D channel is free, and the at the receiver is above the
required threshold; otherwise, an outage occurs for the D2D communication. We
use tools from stochastic geometry to evaluate the performance of the proposed
communication system model with general path-loss exponent in terms of outage
probability for D2D and cellular users. We show that energy harvesting can be a
reliable alternative to power cognitive D2D transmitters while achieving
acceptable performance. Under the same outage requirements as
for the non-cognitive case, cognitive channel access improves the outage
probability for D2D users for both the spectrum access policies.Comment: IEEE Transactions on Communications, to appea
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