4 research outputs found
Energy and Spectral Efficiency Balancing Algorithm for Energy Saving in LTE Downlinks
In wireless network communication environments, Spectral Efficiency (SE) and
Energy Efficiency (EE) are among the major indicators used for evaluating
network performance. However, given the high demand for data rate services and
the exponential growth of energy consumption, SE and EE continue to elicit
increasing attention in academia and industries. Consequently, a study of the
trade-off between these metrics is imperative. In contrast with existing works,
this study proposes an efficient SE and EE trade-off algorithm for saving
energy in downlink Long Term Evolution (LTE) networks to concurrently optimize
SE and EE while considering battery life at the Base Station (BS). The scheme
is formulated as a Multi-objective Optimization Problem (MOP) and its Pareto
optimal solution is examined. In contrast with other algorithms that prolong
battery life by considering the idle state of a BS, thereby increasing average
delay and energy consumption, the proposed algorithm prolongs battery life by
adjusting the initial and final states of a BS to minimize the average delay
and the energy consumption. Similarly, the use of an omni-directional antenna
to spread radio signals to the user equipment in all directions causes high
interference and low spatial reuse. We propose using a directional antenna
instead of an omni-directional antenna by transmitting signals in one direction
which results in no or low interference and high spatial reuse. The proposed
scheme has been extensively evaluated through simulation, where simulation
results prove that the proposed scheme is efficiently able to decrease the
average response delay, improve SE, and minimize energy consumption.Comment: 19 page
An adaptive call admission control with bandwidth reservation for downlink LTE networks
In recent years, consumers of 4G cellular networks have increased exponentially as they discover that the service is user-friendly. Due to the large users and their frequent demands, it is necessary to use the limited network resources that guarantee the eminent standard quality of service (QoS). Call admission control (CAC) scheme has a major impact in assuring QoS for different users with various QoS requirements in 4G networks. Recently, the reservation-based scheme and bandwidth degradation schemes were proposed with the aim to provide effective use of network resources and assure QoS requirements to admitted calls. However, in spite of these several objectives, these schemes are not efficient as a result of the modeling and approximation method that starve the best effort (BE) traffic. The dynamic threshold value approach adjusts handoff call and new call based on time-varying conditions resulted in a waste of network resources, where bandwidth are reserved for handoff call, but at the network environment, there is little or no handoff calls. In this paper, we propose a novel CAC scheme to provide effective use of network resources and avoid the starvation of BE traffic. The scheme introduces an adaptive threshold value, which adjusts the network resources under heavy traffic intensity. In addition, we proposed reservation and degradation approach to admit many users when there is a limited number of bandwidth, which also achieved effective utilization of network resources. Simulation results show that the proposed scheme significantly outperforms the reservation-based scheme and bandwidth degradation schemes in terms of admitting many calls and guaranteeing QoS to all the traffic types in the network. Numerical results imitate to experimental results with insignificant differences
Efficient radio resource management algorithms for downlink long term evolution networks
The increasing demand for wireless network services, particularly for downlink
broadband communication has triggered the evolution of cellular networks.
The Third Generation Partnership Project (3GPP) introduced the Long Term
Evolution (LTE) in response to the forthcoming fourth-generation (4G) cellular
networks. LTE is a very complex and large standard. Its performance is
dependent on the large range of elements. One of the key essential elements
is Radio Resource Management (RRM). RRM has a great impact on the system
performance due to many problematic aspects such as packet scheduling, Call
Admission Control (CAC) and Energy Efficiency (EE).
With the aim to meet the LTE QoS requirements (i.e. Quality of Service (QoS),
fairness provisioning, minimal delay, packet loss, and throughput maximization),
the objective of scheduling algorithm is critical to use limited available
spectrum. As long as choosing an appropriate scheduling algorithm is not
standardized by the 3GPP specification for LTE, vendors are free to adopt,
configure and implement their own algorithms depending on the problems of
the system. Nevertheless, achieving all the intended objectives simultaneously
is difficult. Each problem solved can lead to additional ones. For instance,
radio resource algorithms intended to maximize system throughput are not
appropriate for handling guaranteed bit rate traffic. Hence, the major problem
is developing a scheduling algorithm which creates a trade-off between the
system performances.
It is imperative to note that, in spite of the network-wide control schemes to ease
transmission order, mobile data content overwhelms the available bandwidth for each node in many high traffic times. According to this premise, it is
understandable that the transmission order is an inevitable issue in LTE mobile
networks. Therefore, this thesis examines the efficient resource scheduling
algorithms to be resistant to the unpredicted transmission order patterns.
Firstly, a QoS channel quality identifier algorithm is proposed, to support the
transmission order of users while considering the QoS requirements as well as
the channel condition. The algorithm is based on the idea of the optimization
problem in which resource allocation problem is formulated as an optimization
problem. Optimal priority algorithm uses minimum data rate to guarantees
resource allocation to users but increases the average delay and deteriorate
the network performance. Therefore, the proposed algorithm minimizes the
average delay and improves the network performance.
In addition to network deterioration, the admitting of users to the network
environment contributes to the ineffective use of resources. Thus, we proposed a
call admission control algorithm that admits users to utilize available resources.
It adaptively defines how users should be admitted, by considering the network
conditions.
Furthermore, to deal with the energy consumption problem and provide a
trade-off between spectral and energy efficiency, we proposed a spectral and
energy efficiency trade-off algorithm. Unlike other algorithms that prolong the
battery lifetime by considering the idle state of the base station, thus increasing
the average delay and increases the energy consumption. Our algorithms
prolong the battery life by adjusting the base station using initial and final states.
Consequently, minimizes the average delay as well as low energy consumption.
Similarly, the use of omnidirectional antenna to spread radio signals to UEs
in all directions causes high interference and low special reuse. We proposed
the used of the directional antenna to replaces the omnidirectional antenna by
transmitting signals in one direction 600 and 1200 which resulted in no or less
interference as well as high spatial reuse.
Substantial simulations have been extensively carried out to evaluate the
performance of the proposed algorithms compared with the existing RRM
algorithms. The findings demonstrate that the proposed algorithms have
shown significant improvements, which includes: lowering delay, minimizes
packet loss, improve fairness, and increases the throughput of the system in
the proposed QoS channel quality indicator algorithm. Secondly, the proposed
call admission control algorithm improved the resource utilization algorithm
thus reducing the call block, call dropped, call degradation. This has further
enabled the improvement of data throughput. Lastly, reducing the amount of
energy consumed and lowering delay is shown in the proposed spectral-energy
efficiency algorithm.
Overall, the research has shown promising support and improvements to LTE
networks scheduling algorithms and to associated challenges in wireless communication
paradigm. Likewise, it would be valuable if the proposed scheduling
algorithms are evaluated on anticipated networks covering a large number
of users in further research