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A key challenge in software systems that are exposed to runtime variabilities, such as workload fluctuations and service degradation, is to continuously meet performance requirements. In this paper we present an approach that allows performance self-adaptation using a system model based on queuing networks (QNs), a well-assessed formalism for software performance engineering. Software engineers can...
The paper presents a QoS framework for terminals with multi-RAT (multiple radio access technologies) interfaces for heterogeneous network environment. It investigates a QoS provisioning with vertical multi-homing and multistreaming features for 5G heterogeneous networks. The presented enhanced framework for 5G systems leads to better performance opportunities for multimedia services with very high...
In this work, we study a practical resource allocation (RA) scheme that considers heterogeneous services in OFDMA femtocell networks. Heterogeneous services include guarantees of the minimum data-rate for delay-sensitive (DS) users and the fairness for delay-tolerant (DT) users. The RA problem is formulated to maximize the total throughput of all femtocells while satisfying the constraints of cross-tier...
In this paper, we provide joint subcarrier assignment and power allocation schemes for quality- of-service (QoS)-constrained energy-efficiency (EE) optimization in the downlink of an orthogonal frequency division multiple access (OFDMA)-based two-tier heterogeneous cellular network (HCN). Considering underlay transmission, where spectrum- efficiency (SE) is fully exploited, the EE solution involves...
In this paper, we propose a novel network model for RF-powered cognitive radio networks and ambient backscatter communications. In the network under consideration, each secondary transmitter is able to backscatter primary signals to the gateway for data transfer or to harvest energy from the primary signals and then use that energy to transmit data to the gateway. To maximize overall network throughput...
Distributing scarce spectral resources among the unlicensed users has been an attractive research area for Cognitive Radio Network's (CRN) research community. A resource distribution technique, which emphasizes fairness, ensures allocation of resources for all Secondary Users (SUs) irrespective of their data rates and may cause efficiency loss for the CRN. On the other hand, a throughput based resource...
Recently, Cognitive network has drawn the attention as a promising technology to enhance communication system performance by efficiently utilizing system resources. It provides prompt response to dynamic changes. In this paper, a modified multi-objective particle swarm optimization (M-MOPSO) is proposed in Cognitive IP Multimedia Subsystem (CogIMS) to improve the global network performance. The implementation...
In wireless networks, providing a high fairness allocation isbecoming a very challenging task. This paper has two objectives:firstly, we proposed a new optimization problem called SatisfactionProbability which consists in maximizing the number of satisfiedusers and secondly, we proposed a new scheduling scheme calledQoE-aware Multi-step Opportunistic (QEMO) scheduler. QEMO is builtin an extended cross-layer...
This paper relates to the problem statement of distribution of heterogeneous information and communication system capacity among multiple service flows. We consider the case study of multi-commodity flow problem in terms of utility functions maximization. This approach differs from previously known by separating the optimization problem into layers based on Bellman's Principle of Optimality. It simplifies...
Lately the concepts of smart cities, smart highways and automated vehicles have been rigorously promoted in literature and it depends on the maturity of technology based on VANET (Vehicular Adhoc Network). Even though VANET can be considered as an enabling networking technology to realize smart capabilities in congested city scenarios. However there are many challenges linked with the network and...
In this study, we address the problem of minimizing the energy consumption in future 5G networks by means of a joint optimization of radio access network (RAN) and multi-hop wireless backhaul network. The objective of the optimization is to operate the network with the smallest set of base stations while meeting the quality of service (QoS) requirements of users. We first pose the optimization problem...
Today's indoor wireless networks employ reactive resource allocation methods to provide fair and efficient usage of the communication system. However, their reactive nature limits the quality of service (QoS) that can be offered to the user locations within the environment. In large crowded areas (airports, conferences), networks can get congested and users may suffer from poor QoS. To mitigate this,...
Abstract-In cognitive radio networks, secondary users (SUs) face two conflicting objectives. Each SU seeks to minimize the sensing duration while maximizing the detection probability of primary users (PU) to avoid interfering with their transmissions. Both objectives have a substantial effect on energy efficiency. This paper investigates a noncooperative setting for selecting the sensing duration...
Software-Defined Network (SDN) allows a centralized controller to globally plan packets forwarding according to the operator's objectives. It may require more forwarding rules, and multi-path routing which is allowed in SDN to improve network utilization and throughput means more forwarding rules. However, the forwarding table in TCAM-based SDN switch is an important but limited resource. With this...
Device-to-device (D2D) communication has been considered as a key technique in the fifth generation cellular networks. Power control is critical to ensure satisfactory performance. However, most existing power control schemes focus on delay-unaware metrics, such as throughput and power consumption, thus only applying to delay-insensitive scenarios. To overcome this problem, we in this paper consider...
The IEEE 802.16m based broadband wireless access is a promising technology to provide high speed and wide coverage communications for wireless users. However, how to achieve the desired utilization of the radio frequency bandwidth resource in such networks is an open issue as it covers the radio channel capacity exploitation, channel transmission bandwidth utilization optimization and resource utilization...
We formulate the resource allocation in the downlink of heterogeneous orthogonal frequency division multiple access (OFDMA) networks. Our primary objective is to maximize the system sum throughput subject to service and system constraints, including maximum transmit power, quality of service and per-user subchannel allocation. Due to the intercell interference, the corresponding optimization problem...
In this paper, we address the energy efficient resource allocation problem for a secure orthogonal frequency division multiple access (OFDMA) relay system. In particular, we consider there is a eavesdropper near the base station (BS) which tries to overtake the information sent by BS. We formulate the joint optimization problem with the objective to optimize the energy efficiency of the considered...
Dynamic spectrum access via active spectrum sharing has been considered as a promising approach to improve the spectrum utilization for future wireless systems. In this paper, based on our recent study on the optimal transmit-power allocation for an active spectrum sharing system comprised of single primary-user (PU) and multiple secondary-users (SUs) [7], we move a further step to investigate a more...
We study the problem of optimizing the performance of cognitive radio users with opportunistic real-time applications subject to primary users quality-of-service (QoS) constraints. Two constrained optimization problems are formulated; the first problem is maximizing the secondary user throughput while the second problem is minimizing the secondary user average delay, subject to a common constraint...
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