37,209 research outputs found
Spatial spectrum and energy efficiency of random cellular networks
It is a great challenge to evaluate the network performance of cellular
mobile communication systems. In this paper, we propose new spatial spectrum
and energy efficiency models for Poisson-Voronoi tessellation (PVT) random
cellular networks. To evaluate the user access the network, a Markov chain
based wireless channel access model is first proposed for PVT random cellular
networks. On that basis, the outage probability and blocking probability of PVT
random cellular networks are derived, which can be computed numerically.
Furthermore, taking into account the call arrival rate, the path loss exponent
and the base station (BS) density in random cellular networks, spatial spectrum
and energy efficiency models are proposed and analyzed for PVT random cellular
networks. Numerical simulations are conducted to evaluate the network spectrum
and energy efficiency in PVT random cellular networks.Comment: appears in IEEE Transactions on Communications, April, 201
5G Ultra-dense networks with non-uniform Distributed Users
User distribution in ultra-dense networks (UDNs) plays a crucial role in
affecting the performance of UDNs due to the essential coupling between the
traffic and the service provided by the networks. Existing studies are mostly
based on the assumption that users are uniformly distributed in space. The
non-uniform user distribution has not been widely considered despite that it is
much closer to the real scenario. In this paper, Radiation and Absorbing model
(R&A model) is first adopted to analyze the impact of the non-uniformly
distributed users on the performance of 5G UDNs. Based on the R&A model and
queueing network theory, the stationary user density in each hot area is
investigated. Furthermore, the coverage probability, network throughput and
energy efficiency are derived based on the proposed theoretical model. Compared
with the uniformly distributed assumption, it is shown that non-uniform user
distribution has a significant impact on the performance of UDNs.Comment: 14 pages, 10 figure
D2D Data Offloading in Vehicular Environments with Optimal Delivery Time Selection
Within the framework of a Device-to-Device (D2D) data offloading system for
cellular networks, we propose a Content Delivery Management System (CDMS) in
which the instant for transmitting a content to a requesting node, through a
D2D communication, is selected to minimize the energy consumption required for
transmission. The proposed system is particularly fit to highly dynamic
scenarios, such as vehicular networks, where the network topology changes at a
rate which is comparable with the order of magnitude of the delay tolerance. We
present an analytical framework able to predict the system performance, in
terms of energy consumption, using tools from the theory of point processes,
validating it through simulations, and provide a thorough performance
evaluation of the proposed CDMS, in terms of energy consumption and spectrum
use. Our performance analysis compares the energy consumption and spectrum use
obtained with the proposed scheme with the performance of two benchmark
systems. The first one is a plain classic cellular scheme, the second is a D2D
data offloading scheme (that we proposed in previous works) in which the D2D
transmissions are performed as soon as there is a device with the required
content within the maximum D2D transmission range..
5G green cellular networks considering power allocation schemes
It is important to assess the effect of transmit power allocation schemes on
the energy consumption on random cellular networks. The energy efficiency of 5G
green cellular networks with average and water-filling power allocation schemes
is studied in this paper. Based on the proposed interference and achievable
rate model, an energy efficiency model is proposed for MIMO random cellular
networks. Furthermore, the energy efficiency with average and water-filling
power allocation schemes are presented, respectively. Numerical results
indicate that the maximum limits of energy efficiency are always there for MIMO
random cellular networks with different intensity ratios of mobile stations
(MSs) to base stations (BSs) and channel conditions. Compared with the average
power allocation scheme, the water-filling scheme is shown to improve the
energy efficiency of MIMO random cellular networks when channel state
information (CSI) is attainable for both transmitters and receivers.Comment: 14 pages, 7 figure
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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