3 research outputs found
An Energy Efficient D2D Model with Guaranteed Quality of Service for Cloud Radio Access Networks
This paper proposes a spectrum selection scheme and a transmit power
minimization scheme for a device-to-device (D2D) network cross-laid with a
cloud radio access network (CRAN). The D2D communications are allowed as an
overlay to the CRAN as well as in the unlicensed industrial, scientific and
medical radio (ISM) band. A link distance based scheme is proposed and
closed-form approximations are derived for the link distance thresholds to
select the operating band of the D2D users. Furthermore, analytical expressions
are derived to calculate the minimum required transmit power to achieve a
guaranteed level of quality of service in each operating band. The results
demonstrate that the proposed scheme achieves nearly 50% power saving compared
to a monolithic (purely overlay or purely ISM band) D2D network
Energy Efficient Power Allocation for Device-to-Device Communications Underlaid Cellular Networks Using Stochastic Geometry
In this paper, we study an energy efficiency maximization problem in uplink
for D2D communications underlaid with cellular networks on multiple bands.
Utilizing stochastic geometry, we derive closed-form expressions for the
average sum rate, successful transmission probability, and energy efficiency of
cellular and D2D users. Then, we formulate an optimization problem to jointly
maximize the energy efficiency of D2D and cellular users and obtain optimum
transmission power of both D2D and cellular users. In the optimization problem,
we guarantee the QoS of users by taking into account the success transmission
probability on each link. To solve the problem, first we convert the problem
into canonical convex form. Afterwards, we solve the problem in two phases,
energy efficiency maximization of devices and energy efficiency maximization of
cellular users. In the first phase, we maximize the energy efficiency of D2D
users and feed the solution to the second phase where we maximize the energy
efficiency of cellular users. Simulation results reveal that significant energy
efficiency can be attained e.g., 10% energy efficiency improvement compared to
fix transmission power in high density scenario.Comment: 20 pages, 7 figures, Journal paper, accepted by ET
Power Control and Channel Allocation for D2D Underlaid Cellular Networks
Device-to-Device (D2D) communications underlaying cellular networks is a
viable network technology that can potentially increase spectral utilization
and improve power efficiency for proximitybased wireless applications and
services. However, a major challenge in such deployment scenarios is the
interference caused by D2D links when sharing the same resources with cellular
users. In this work, we propose a channel allocation (CA) scheme together with
a set of three power control (PC) schemes to mitigate interference in a D2D
underlaid cellular system modeled as a random network using the mathematical
tool of stochastic geometry. The novel aspect of the proposed CA scheme is that
it enables D2D links to share resources with multiple cellular users as opposed
to one as previously considered in the literature. Moreover, the accompanying
distributed PC schemes further manage interference during link establishment
and maintenance. The first two PC schemes compensate for large-scale path-loss
effects and maximize the D2D sum rate by employing distance-dependent pathloss
parameters of the D2D link and the base station, including an error estimation
margin. The third scheme is an adaptive PC scheme based on a variable target
signal-to-interference-plus-noise ratio, which limits the interference caused
by D2D users and provides sufficient coverage probability for cellular users.
Closed-form expressions for the coverage probability of cellular links, D2D
links, and sum rate of D2D links are derived in terms of the allocated power,
density of D2D links, and path-loss exponent. The impact of these key system
parameters on network performance is analyzed and compared with previous work.
Simulation results demonstrate an enhancement in cellular and D2D coverage
probabilities, and an increase in spectral and power efficiency.Comment: 35 page