1,460 research outputs found
Energy efficiency in heterogeneous wireless access networks
In this article, we bring forward the important aspect of energy savings in wireless access networks. We specifically focus on the energy saving opportunities in the recently evolving heterogeneous networks (HetNets), both Single- RAT and Multi-RAT. Issues such as sleep/wakeup cycles and interference management are discussed for co-channel Single-RAT HetNets. In addition to that, a simulation based study for LTE macro-femto HetNets is presented, indicating the need for dynamic energy efficient resource management schemes. Multi-RAT HetNets also come with challenges such as network integration, combined resource management and network selection. Along with a discussion on these challenges, we also investigate the performance of the conventional WLAN-first network selection mechanism in terms of energy efficiency (EE) and suggest that EE can be improved by the application of intelligent call admission control policies
Green Networking in Cellular HetNets: A Unified Radio Resource Management Framework with Base Station ON/OFF Switching
In this paper, the problem of energy efficiency in cellular heterogeneous
networks (HetNets) is investigated using radio resource and power management
combined with the base station (BS) ON/OFF switching. The objective is to
minimize the total power consumption of the network while satisfying the
quality of service (QoS) requirements of each connected user. We consider the
case of co-existing macrocell BS, small cell BSs, and private femtocell access
points (FAPs). Three different network scenarios are investigated, depending on
the status of the FAPs, i.e., HetNets without FAPs, HetNets with closed FAPs,
and HetNets with semi-closed FAPs. A unified framework is proposed to
simultaneously allocate spectrum resources to users in an energy efficient
manner and switch off redundant small cell BSs. The high complexity dual
decomposition technique is employed to achieve optimal solutions for the
problem. A low complexity iterative algorithm is also proposed and its
performances are compared to those of the optimal technique. The particularly
interesting case of semi-closed FAPs, in which the FAPs accept to serve
external users, achieves the highest energy efficiency due to increased degrees
of freedom. In this paper, a cooperation scheme between FAPs and mobile
operator is also investigated. The incentives for FAPs, e.g., renewable energy
sharing and roaming prices, enabling cooperation are discussed to be considered
as a useful guideline for inter-operator agreements.Comment: 15 pages, 9 Figures, IEEE Transactions on Vehicular Technology 201
Matching Theory for Future Wireless Networks: Fundamentals and Applications
The emergence of novel wireless networking paradigms such as small cell and
cognitive radio networks has forever transformed the way in which wireless
systems are operated. In particular, the need for self-organizing solutions to
manage the scarce spectral resources has become a prevalent theme in many
emerging wireless systems. In this paper, the first comprehensive tutorial on
the use of matching theory, a Nobelprize winning framework, for resource
management in wireless networks is developed. To cater for the unique features
of emerging wireless networks, a novel, wireless-oriented classification of
matching theory is proposed. Then, the key solution concepts and algorithmic
implementations of this framework are exposed. Then, the developed concepts are
applied in three important wireless networking areas in order to demonstrate
the usefulness of this analytical tool. Results show how matching theory can
effectively improve the performance of resource allocation in all three
applications discussed
Interference Management Based on RT/nRT Traffic Classification for FFR-Aided Small Cell/Macrocell Heterogeneous Networks
Cellular networks are constantly lagging in terms of the bandwidth needed to
support the growing high data rate demands. The system needs to efficiently
allocate its frequency spectrum such that the spectrum utilization can be
maximized while ensuring the quality of service (QoS) level. Owing to the
coexistence of different types of traffic (e.g., real-time (RT) and
non-real-time (nRT)) and different types of networks (e.g., small cell and
macrocell), ensuring the QoS level for different types of users becomes a
challenging issue in wireless networks. Fractional frequency reuse (FFR) is an
effective approach for increasing spectrum utilization and reducing
interference effects in orthogonal frequency division multiple access networks.
In this paper, we propose a new FFR scheme in which bandwidth allocation is
based on RT/nRT traffic classification. We consider the coexistence of small
cells and macrocells. After applying FFR technique in macrocells, the remaining
frequency bands are efficiently allocated among the small cells overlaid by a
macrocell. In our proposed scheme, total frequency-band allocations for
different macrocells are decided on the basis of the traffic intensity. The
transmitted power levels for different frequency bands are controlled based on
the level of interference from a nearby frequency band. Frequency bands with a
lower level of interference are assigned to the RT traffic to ensure a higher
QoS level for the RT traffic. RT traffic calls in macrocell networks are also
given a higher priority compared with nRT traffic calls to ensure the low
call-blocking rate. Performance analyses show significant improvement under the
proposed scheme compared with conventional FFR schemes
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