9,025 research outputs found
Effect of Energy Harvesting on Stable Throughput in Cooperative Relay Systems
In this paper, the impact of energy constraints on a two-hop network with a
source, a relay and a destination under random medium access is studied. A
collision channel with erasures is considered, and the source and the relay
nodes have energy harvesting capabilities and an unlimited battery to store the
harvested energy. Additionally, the source and the relay node have external
traffic arrivals and the relay forwards a fraction of the source node's traffic
to the destination; the cooperation is performed at the network level. An inner
and an outer bound of the stability region for a given transmission probability
vector are obtained. Then, the closure of the inner and the outer bound is
obtained separately and they turn out to be identical. This work is not only a
step in connecting information theory and networking, by studying the maximum
stable throughput region metric but also it taps the relatively unexplored and
important domain of energy harvesting and assesses the effect of that on this
important measure.Comment: 20 pages, 4 figure
Power-Optimal Feedback-Based Random Spectrum Access for an Energy Harvesting Cognitive User
In this paper, we study and analyze cognitive radio networks in which
secondary users (SUs) are equipped with Energy Harvesting (EH) capability. We
design a random spectrum sensing and access protocol for the SU that exploits
the primary link's feedback and requires less average sensing time. Unlike
previous works proposed earlier in literature, we do not assume perfect
feedback. Instead, we take into account the more practical possibilities of
overhearing unreliable feedback signals and accommodate spectrum sensing
errors. Moreover, we assume an interference-based channel model where the
receivers are equipped with multi-packet reception (MPR) capability.
Furthermore, we perform power allocation at the SU with the objective of
maximizing the secondary throughput under constraints that maintain certain
quality-of-service (QoS) measures for the primary user (PU)
Decentralized Delay Optimal Control for Interference Networks with Limited Renewable Energy Storage
In this paper, we consider delay minimization for interference networks with
renewable energy source, where the transmission power of a node comes from both
the conventional utility power (AC power) and the renewable energy source. We
assume the transmission power of each node is a function of the local channel
state, local data queue state and local energy queue state only. In turn, we
consider two delay optimization formulations, namely the decentralized
partially observable Markov decision process (DEC-POMDP) and Non-cooperative
partially observable stochastic game (POSG). In DEC-POMDP formulation, we
derive a decentralized online learning algorithm to determine the control
actions and Lagrangian multipliers (LMs) simultaneously, based on the policy
gradient approach. Under some mild technical conditions, the proposed
decentralized policy gradient algorithm converges almost surely to a local
optimal solution. On the other hand, in the non-cooperative POSG formulation,
the transmitter nodes are non-cooperative. We extend the decentralized policy
gradient solution and establish the technical proof for almost-sure convergence
of the learning algorithms. In both cases, the solutions are very robust to
model variations. Finally, the delay performance of the proposed solutions are
compared with conventional baseline schemes for interference networks and it is
illustrated that substantial delay performance gain and energy savings can be
achieved
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