The Department of Defense will deploy the first generation of future force communicationsnetworks and battle command systems over the next several years. These future force systems will have the ability to characteri...
详细信息
ISBN:
(纸本)9781424406173
The Department of Defense will deploy the first generation of future force communicationsnetworks and battle command systems over the next several years. These future force systems will have the ability to characterize and meter their offered traffic based on priority using quality of service architectures such as differentiated services and integrated services. This implementation of quality of service will allow future communicationsnetworks to process offered traffic under congestion conditions according to Commanders policy and traffic priority. Network congestion can arise from a combination of reduced transmission performance or increased offered load, or both. Transmission performance, in turn, can be dramatically affected by the presence of interference. Frequency assignment systems and procedures in use today seek to prevent interference, and thus degraded transmission performance, by assigning transmission frequencies that reduce or eliminate the interference potential. This is usually accomplished based exclusively on interference thresholds that compare potential interfering energy with signal or internal noise thresholds. QoS-enabled networks may have a higher degree of interference "tolerance " because overall network performance for higher priority traffic flows may not be impacted by the interference. This paper describes how a QoS-enabled network might tolerate higher interference thresholds and thus enable tighter frequency reuse. It also offers suggestions for additional areas of study related to this subject.
Integration of heterogeneous networks constitutes the main concern of the nextgeneration of mobile networks (4G). This integration is closely related to mobility management in the sense that a mobile user will move f...
详细信息
ISBN:
(纸本)1424404940
Integration of heterogeneous networks constitutes the main concern of the nextgeneration of mobile networks (4G). This integration is closely related to mobility management in the sense that a mobile user will move freely across mobile networks without connection disruption. Mobile IP based approaches suffers from drawbacks such as packet loss, high throughputs and handover latency. In this paper, we propose a new SCTP (Stream control Transmission Protocol) mobility scheme supporting vertical handoff. The proposed scheme does not require any special infrastructure and presents less handoff latency compared to MIPv6 based approaches.
In new generation cellular networks, opportunistic schedulers take advantage from the delay-tolerance of data applications to ensure that transmission occurs when radio channel conditions are most favourable. "Pr...
详细信息
ISBN:
(纸本)9780780394551
In new generation cellular networks, opportunistic schedulers take advantage from the delay-tolerance of data applications to ensure that transmission occurs when radio channel conditions are most favourable. "Proportional Fair" (PF) is a well-known opportunistic scheduler that provides a good compromise between fairness and efficiency when transmitting long flows. Unfortunately, the PF algorithm is not efficient for short transfers, which represent the majority of data flows. Moreover, the lack of coordination between opportunistic scheduling and the congestion control mechanism of TCP induce very poor performance especially for short-lived flows. In this paper, we propose three enhanced scheduling approaches that significantly reduce the transfer time of short flows without a significant degradation of the QoS provided to long flows.
The proceedings contain 51 papers. The topics discussed include: towards distributed communications systems: relay-based wireless networks;dimensioning of multiservice links taking account of soft blocking;transient a...
详细信息
ISBN:
(纸本)3540344292
The proceedings contain 51 papers. The topics discussed include: towards distributed communications systems: relay-based wireless networks;dimensioning of multiservice links taking account of soft blocking;transient analysis of a queuing system with matrix-geometric methods;on modeling video traffic from multiplexed MPEG-4 videoconference streams;a new MAC protocol based on multimedia traffic prediction in satellite systems;measurement-based optimization of a 3G core network: a case study;a middleware approach for reducing the network cost of location traffic in cellular networks;location conveyance in the IP multimedia subsystem;a random backoff algorithm for wireless sensor networks;the structure of the reactive performancecontrol system for wireless channels;and achieving relative service differentiation for TCP traffic in satellite IP networks using congestion pricing.
Major research challenges in the nextgeneration (4G) of wireless networks include the provisioning of worldwide seamless mobility across heterogeneous wireless networks, the improvement of end-to-end Quality of Servi...
详细信息
The work presented in this paper1 focuses on a new approach in provisioning Quality of Service (QoS) in ad hoc wireless networks, aiming at making the best use of ad hoc networking as a candidate technology for next g...
详细信息
Orthogonal frequency division multiple access (OFDMA) systems emerge as potential choices for the development of the nextgeneration (4G) mobile communications system mainly due to their bandwidth efficiency and capab...
详细信息
ISBN:
(纸本)9781424405688
Orthogonal frequency division multiple access (OFDMA) systems emerge as potential choices for the development of the nextgeneration (4G) mobile communications system mainly due to their bandwidth efficiency and capability of inter symbol interference (ISI) combat. Recently, dynamic resource allocation (DRA) technique is intensively studied to enhance system performance such as throughput maximization, power minimization, fairness and so forth. However, the tradeoff between maximal throughput and fairness gets more attention since it adapts to varying wireless network conditions as well as provides reasonable fairness among users. In this paper, we focus on achieving the tradeoff in the downlink case. A comparison between several DRA schemes is given to illustrate how to get the tradeoff in a downlink OFDMA system.
Optical networks are becoming an inevitable technology in the nextgeneration Internet. Optical WDM networks require a control network for automatic and rapid configuration. A control plane is under standardization by...
详细信息
ISBN:
(纸本)9781424402212
Optical networks are becoming an inevitable technology in the nextgeneration Internet. Optical WDM networks require a control network for automatic and rapid configuration. A control plane is under standardization by the Internet Engineering Task Force (IETF) under the name Generalized Multi-Protocol Label Switching (GMPLS). However, this control plane is unaware of the specifications of the services to be enforced. This work presents a policy-based management architecture adapted to an emerging kind of optical networks called hybrid photonic networks. Contributing to network flexibility, we present extensions to the management plane of these transparent wavelength and switching capable networks that provide the means to leverage their inherent capabilities. The proposed management architecture would provide optical network operators with the possibility to provision optical services, defined through high level service contracts, in an efficient and dynamic way.
Adaptive resource management has become a key technique for the next-generation wireless systems to provide desired services at appropriate QoS. Most of the current. resource management algorithms are confined to a si...
详细信息
Adaptive resource management has become a key technique for the next-generation wireless systems to provide desired services at appropriate QoS. Most of the current. resource management algorithms are confined to a single layer of the, network protocol stack, which leads to an inferior performance. In this paper, we propose a joint MAC-PHY layer resource management algorithm for wireless OFDM networks. The algorithm aims to maximize the. system power efficiency given that the fulfillment of the QoS as well as the fairness is guaranteed. We formulate the integrated design of packet scheduling, subcarrier allocation,, and power control into a constrained optimization problem. the formulation defines the interaction and cooperation between different components of the algorithm as well as the information exchange between the PHY and MAC layers. A reduced-complexity scheme that solves the optimization problem in polynomial time is then developed based on the special structure of the problem. Analytical and numerical results will show that the proposed algorithm is able to guarantee-the same degree of QoS and fairness as the fair queueing systems do in wired channels. Meanwhile, the power efficiency and system performance are significantly improved compared to traditional systems where resources are allocated based on a strict layering. architecture.
Preemption and adaptation are two common techniques for controlling inelastic traffic such as streaming media. Adaptation policies dynamically increase or decrease the transmission rate of the stream in response to th...
详细信息
暂无评论