3,880 research outputs found
Improved capacity bounds for the binary energy harvesting channel
Abstract—We consider a binary energy harvesting channel (BEHC) where the encoder has unit energy storage capacity. We first show that an encoding scheme based on block indexing is asymptotically optimal for small energy harvesting rates. We then present a novel upper bounding technique, which upper bounds the rate by lower-bounding the rate of information leakage to the receiver regarding the energy harvesting process. Finally, we propose a timing based hybrid encoding scheme that achieves rates within 0.03 bits/channel use of the upper bound; hence determining the capacity to within 0.03 bits/channel use. I
Interactive Joint Transfer of Energy and Information
In some communication networks, such as passive RFID systems, the energy used
to transfer information between a sender and a recipient can be reused for
successive communication tasks. In fact, from known results in physics, any
system that exchanges information via the transfer of given physical resources,
such as radio waves, particles and qubits, can conceivably reuse, at least
part, of the received resources. This paper aims at illustrating some of the
new challenges that arise in the design of communication networks in which the
signals exchanged by the nodes carry both information and energy. To this end,
a baseline two-way communication system is considered in which two nodes
communicate in an interactive fashion. In the system, a node can either send an
"on" symbol (or "1"), which costs one unit of energy, or an "off" signal (or
"0"), which does not require any energy expenditure. Upon reception of a "1"
signal, the recipient node "harvests", with some probability, the energy
contained in the signal and stores it for future communication tasks. Inner and
outer bounds on the achievable rates are derived. Numerical results demonstrate
the effectiveness of the proposed strategies and illustrate some key design
insights.Comment: 29 pages, 11 figures, Submitted in IEEE Transactions on
Communications. arXiv admin note: substantial text overlap with
arXiv:1204.192
Power Allocation for Conventional and Buffer-Aided Link Adaptive Relaying Systems with Energy Harvesting Nodes
Energy harvesting (EH) nodes can play an important role in cooperative
communication systems which do not have a continuous power supply. In this
paper, we consider the optimization of conventional and buffer-aided link
adaptive EH relaying systems, where an EH source communicates with the
destination via an EH decode-and-forward relay. In conventional relaying,
source and relay transmit signals in consecutive time slots whereas in
buffer-aided link adaptive relaying, the state of the source-relay and
relay-destination channels determines whether the source or the relay is
selected for transmission. Our objective is to maximize the system throughput
over a finite number of transmission time slots for both relaying protocols. In
case of conventional relaying, we propose an offline and several online joint
source and relay transmit power allocation schemes. For offline power
allocation, we formulate an optimization problem which can be solved optimally.
For the online case, we propose a dynamic programming (DP) approach to compute
the optimal online transmit power. To alleviate the complexity inherent to DP,
we also propose several suboptimal online power allocation schemes. For
buffer-aided link adaptive relaying, we show that the joint offline
optimization of the source and relay transmit powers along with the link
selection results in a mixed integer non-linear program which we solve
optimally using the spatial branch-and-bound method. We also propose an
efficient online power allocation scheme and a naive online power allocation
scheme for buffer-aided link adaptive relaying. Our results show that link
adaptive relaying provides performance improvement over conventional relaying
at the expense of a higher computational complexity.Comment: Submitted to IEEE Transactions on Wireless Communication
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