438 research outputs found
A Utility Proportional Fairness Radio Resource Block Allocation in Cellular Networks
This paper presents a radio resource block allocation optimization problem
for cellular communications systems with users running delay-tolerant and
real-time applications, generating elastic and inelastic traffic on the network
and being modelled as logarithmic and sigmoidal utilities respectively. The
optimization is cast under a utility proportional fairness framework aiming at
maximizing the cellular systems utility whilst allocating users the resource
blocks with an eye on application quality of service requirements and on the
procedural temporal and computational efficiency. Ultimately, the sensitivity
of the proposed modus operandi to the resource variations is investigated
Coding scheme for 3D vertical flash memory
Recently introduced 3D vertical flash memory is expected to be a disruptive
technology since it overcomes scaling challenges of conventional 2D planar
flash memory by stacking up cells in the vertical direction. However, 3D
vertical flash memory suffers from a new problem known as fast detrapping,
which is a rapid charge loss problem. In this paper, we propose a scheme to
compensate the effect of fast detrapping by intentional inter-cell interference
(ICI). In order to properly control the intentional ICI, our scheme relies on a
coding technique that incorporates the side information of fast detrapping
during the encoding stage. This technique is closely connected to the
well-known problem of coding in a memory with defective cells. Numerical
results show that the proposed scheme can effectively address the problem of
fast detrapping.Comment: 7 pages, 9 figures. accepted to ICC 2015. arXiv admin note: text
overlap with arXiv:1410.177
Self-Repairing Disk Arrays
As the prices of magnetic storage continue to decrease, the cost of replacing
failed disks becomes increasingly dominated by the cost of the service call
itself. We propose to eliminate these calls by building disk arrays that
contain enough spare disks to operate without any human intervention during
their whole lifetime. To evaluate the feasibility of this approach, we have
simulated the behavior of two-dimensional disk arrays with n parity disks and
n(n-1)/2 data disks under realistic failure and repair assumptions. Our
conclusion is that having n(n+1)/2 spare disks is more than enough to achieve a
99.999 percent probability of not losing data over four years. We observe that
the same objectives cannot be reached with RAID level 6 organizations and would
require RAID stripes that could tolerate triple disk failures.Comment: Part of ADAPT Workshop proceedings, 2015 (arXiv:1412.2347
Power Allocation and Cooperative Diversity in Two-Way Non-Regenerative Cognitive Radio Networks
In this paper, we investigate the performance of a dual-hop block fading
cognitive radio network with underlay spectrum sharing over independent but not
necessarily identically distributed (i.n.i.d.) Nakagami- fading channels.
The primary network consists of a source and a destination. Depending on
whether the secondary network which consists of two source nodes have a single
relay for cooperation or multiple relays thereby employs opportunistic relay
selection for cooperation and whether the two source nodes suffer from the
primary users' (PU) interference, two cases are considered in this paper, which
are referred to as Scenario (a) and Scenario (b), respectively. For the
considered underlay spectrum sharing, the transmit power constraint of the
proposed system is adjusted by interference limit on the primary network and
the interference imposed by primary user (PU). The developed new analysis
obtains new analytical results for the outage capacity (OC) and average symbol
error probability (ASEP). In particular, for Scenario (a), tight lower bounds
on the OC and ASEP of the secondary network are derived in closed-form. In
addition, a closed from expression for the end-to-end OC of Scenario (a) is
achieved. With regards to Scenario (b), a tight lower bound on the OC of the
secondary network is derived in closed-form. All analytical results are
corroborated using Monte Carlo simulation method
Location Aided Energy Balancing Strategy in Green Cellular Networks
Most cellular network communication strategies are focused on data traffic
scenarios rather than energy balance and efficient utilization. Thus mobile
users in hot cells may suffer from low throughput due to energy loading
imbalance problem. In state of art cellular network technologies, relay
stations extend cell coverage and enhance signal strength for mobile users.
However, busy traffic makes the relay stations in hot area run out of energy
quickly. In this paper, we propose an energy balancing strategy in which the
mobile nodes are able to dynamically select and hand over to the relay station
with the highest potential energy capacity to resume communication. Key to the
strategy is that each relay station merely maintains two parameters that
contains the trend of its previous energy consumption and then predicts its
future quantity of energy, which is defined as the relay station potential
energy capacity. Then each mobile node can select the relay station with the
highest potential energy capacity. Simulations demonstrate that our approach
significantly increase the aggregate throughput and the average life time of
relay stations in cellular network environment.Comment: 6 pages, 5 figures. arXiv admin note: text overlap with
arXiv:1108.5493 by other author
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