Fair resource allocation with guaranteed statistical QoS for multimedia traffic in wideband CDMA cellular network

A dynamic fair resource allocation scheme is proposed to efficiently support real-time and non-real-time multimedia traffic with guaranteed statistical quality of service (QoS) in the uplink of a wideband code-division multiple access (CDMA) cellular network. The scheme uses the generalized processor sharing (GPS) fair service discipline to allocate uplink channel-resources, taking into account the characteristics of channel fading and intercell interference. In specific, the resource allocated to each traffic flow is proportional to an assigned weighting factor. For real-time traffic, the assigned weighting factor is a constant in order to guarantee the traffic statistical delay bound requirement; for non-real-time traffic, the assigned weighting factor can be adjusted dynamically according to fading, channel states and the traffic statistical fairness bound requirement. Compared with the conventional static-weight scheme, the proposed dynamic-weight scheme achieves capacity gain. A flexible trade-off between the GPS fairness and efficient resource utilization can also be achieved. Analysis and simulation results demonstrate that the proposed scheme enhances radio resource utilization and guarantees statistical QoS under different fairness bound requirements.     

突发业务环境下CBR业务性能的实验分析

CBR业务是一类极为重要的实时业务,能否有效地传递这类业务关系到从现有网络向ATM的过渡,因此CBR业务的服务质量是一个值得研究的重要课题。本文利用计算机仿真的方法,全面地分析了突发业务环境下,影响CBR业务服务质量的各种因素,指出复接器占有率、缓冲区容量、背景强度、背景流的自相关特征对CBR业务的时延及时延抖动有很大的影响,尤其是背景流具有长时相关性时,CBR业务的服务质量将严重恶化,必须设法加以控制。     

An FDD wideband CDMA MAC protocol with minimum-power allocation and GPS-scheduling for wireless wide area multimedia networks

A frequency division duplex (FDD) wideband code division multiple access (CDMA) medium access control (MAC) protocol is developed for wireless wide area multimedia networks. In order to reach the maximum system capacity and guarantee the heterogeneous bit error rates (BERs) of multimedia traffic, a minimum-power allocation algorithm is first derived, where both multicode (MC) and orthogonal variable spreading factor (OVSF) transmissions are assumed. Based on the minimum-power allocation algorithm, a multimedia wideband CDMA generalized processor sharing (GPS) scheduling scheme is proposed. It provides fair queueing to multimedia traffic with different QoS constraints. It also takes into account the limited number of code channels for each user and the variable system capacity due to interference experienced by users in a CDMA network. To control the admission of real-time connections, a connection admission control (CAC) scheme is proposed, in which the effective bandwidth admission region is derived based on the minimum-power allocation algorithm. With the proposed resource management algorithms, the MAC protocol significantly increases system throughput, guarantees BER, and improves QoS metrics of multimedia traffic.     

Source time scale and optimal buffer/bandwidth tradeoff forheterogeneous regulated traffic in a network node

We study the problem of resource allocation and control for a network node with regulated traffic. Both guaranteed lossless service and statistical service with small loss probability are considered. We investigate the relationship between source characteristics and the buffer/bandwidth tradeoff under both services. Our contributions are the following. For guaranteed lossless service, we find that the optimal resource allocation scheme suggests that sources sharing a network node with finite bandwidth and buffer space divide into groups according to time scales defined by their leaky-bucket parameters. This time-scale separation determines the manner by which the buffer and bandwidth resources at the network node are shared among the sources. For statistical service with a small loss probability, we present a new approach for estimating the loss probability in a shared buffer multiplexer using the “extremal” on-off, periodic sources. Under this approach, the optimal resource allocation for statistical service is achieved by maximizing both the benefits of buffering sharing and bandwidth sharing. The optimal buffer/bandwidth tradeoff is again determined by a time-scale separation     

CELL LOSS QUALITY OF SERVICE IN AN INTEGRATED TRAFFIC ATM NETWORK

This paper explores and evaluates several aspects of quality of service (QOS) in an integrated traffic ATM network. Specifically, we consider the relationships between service class definitions, usage parameter control (UPC) or policing of customer traffic, network resource allocation mechanisms, and specific network conditions under which realistic QOS limits on cell loss ratio (CLR) can be met. Traffic consists of a mixture of voice, video, image and data divided into two service classes for UPC and network resource allocation. The block oriented network simulator (BONeS) tool is used for performance evaluations. Limitations associated with evaluating very low CLR values (e.g. 10⁻⁸ and 10⁻⁶) via simulation are overcome by a hybrid simulation and extrapolation technique. It is found that these stringent QOS limits on CLR can be met for most traffic with the techniques used here, reasonable backbone trunk loads (75 per cent) and reasonable buffer sizes (200–250 cell buffers per queue). However, meeting similar limits for extremely bursty traffic (such as our image traffic model) would require extra care in network design and operation, including judicious segregation of traffic.     

控制接入ATM网的突发话音

ＡＴＭ网在同一条连接上能支持多媒体业务,各种媒体的速率、突发度参数和它们之间的相位关系都不同。要保证各种业务的服务质量（ＱＯＳ）,需要引入流量控制算法。本文介绍用于用户网络接口（ＵＮＩ）上的流量控制算法。     

A Network Calculus With Effective Bandwidth

This paper establishes a link between two principal tools for the analysis of network traffic, namely, effective bandwidth and network calculus. It is shown that a general version of effective bandwidth can be expressed within the framework of a probabilistic version of the network calculus, where both arrivals and service are specified in terms of probabilistic bounds. By formulating well-known effective bandwidth expressions in terms of probabilistic envelope functions, the developed network calculus can be applied to a wide range of traffic types, including traffic that has self-similar characteristics. As applications, probabilistic lower bounds are presented on the service given by three different scheduling algorithms: static priority, earliest deadline first, and generalized processor sharing. Numerical examples show the impact of specific traffic models and scheduling algorithms on the multiplexing gain in a network.     

Efficient resource allocation for China's 3G/4G wireless networks

The all-IP DiffServ model is expected to be the most promising architecture for QoS provisioning in China's next-generation wireless networks, due to its scalability, convenience for mobility support, and capability of interworking heterogeneous radio access networks. This article focuses on efficient resource allocation in a wireless DiffServ architecture. Resource utilization efficiency is particularly important for China's wireless networks as the mobile user density in China is and will continue to be much higher than that in other countries. More specifically, we propose a novel buffer sharing scheme to provide assured service for real-time layer-coded multimedia traffic, which can guarantee the specific packet loss requirement of each layer with UDP as the transport layer protocol. An adaptive optimal buffer configuration can be applied to achieve maximum resource utilization over the time-varying channel. Assured service is also provided to TCP data traffic for guaranteed throughput, where the cross-layer coupling between the TCP layer and link layer is exploited to efficiently utilize the wireless resources.     

Statistical multiplexing and buffer sharing in multimediahigh-speed networks: a frequency-domain perspective

We study the effectiveness of statistical multiplexing and buffer sharing under the multimedia high-speed networking environment. We focus on the impact of frequency-domain source characteristics on dynamic resource sharing. By applying a novel statistical matching technique, we can, for the first time, investigate the multiplexing performance of a wide-range of realistic traffic sources using sophisticated traffic models. It has been shown that the effectiveness of statistical multiplexing and buffer sharing highly depends on the frequency-domain characteristics of the traffic as well as the corresponding QoS requirements. For practical “low-frequency” sources; e.g., VBR-video streams and LAN-to-LAN traffic, we show that significant savings in bandwidth and buffer-space can be achieved via resource sharing under practical loss and delay constraints. These findings re-illustrate the important role of traffic characteristics in the design/selection of network control strategies. The trade-offs among different design alternatives (e.g., multiplexing versus buffering) and the implications on some control schemes, e.g., traffic shaping/input-rate control, are also discussed     

Design and analysis of a bandwidth management framework forATM-based broadband ISDN

When designing and configuring an ATM-based B-ISDN, it remains difficult to guarantee the quality of service (QoS) for different service classes, while still allowing enough statistical sharing of bandwidth so that the network is efficiently utilized. These two goals are often conflicting. Guaranteeing QoS requires traffic isolation, as well as allocation of enough network resources (e.g., buffer space and bandwidth) to each call. However, statistical bandwidth sharing means the network resources should be occupied on demand, leading to less traffic isolation and minimal resource allocation. The authors address this problem by proposing and evaluating a network-wide bandwidth management framework in which an appropriate compromise between the two conflicting goals is achieved. Specifically, the bandwidth management framework consists of a network model and a network-wide bandwidth allocation and sharing strategy. Implementation issues related to the framework are discussed. For real-time applications the authors obtain maximum queuing delay and queue length, which are important in buffer design and VP (virtual path) routing     

Novel Radio Link Buffer Management Schemes for End-User Multi-class Traffic in High Speed Packet Access Networks

The requirement to provide multimedia services with QoS support in mobile networks has led to standardization and deployment of high speed data access technologies such as the High Speed Downlink Packet Access (HSDPA) system. HSDPA improves downlink packet data and multimedia services support in WCDMA-based cellular networks. As is the trend in emerging wireless access technologies, HSDPA supports end-user multi-class sessions comprising parallel flows with diverse Quality of Service (QoS) requirements, such as real-time (RT) voice or video streaming concurrent with non real-time (NRT) data service being transmitted to the same user, with differentiated queuing at the radio link interface. Hence, in this paper we present and evaluate novel radio link buffer management schemes for QoS control of multimedia traffic comprising concurrent RT and NRT flows in the same HSDPA end-user session. The new buffer management schemes—Enhanced Time Space Priority (E-TSP) and Dynamic Time Space Priority (D-TSP)—are designed to improve radio link and network resource utilization as well as optimize end-to-end QoS performance of both RT and NRT flows in the end-user session. Both schemes are based on a Time-Space Priority (TSP) queuing system, which provides joint delay and loss differentiation between the flows by queuing (partially) loss tolerant RT flow packets for higher transmission priority but with restricted access to the buffer space, whilst allowing unlimited access to the buffer space for delay-tolerant NRT flow but with queuing for lower transmission priority. Experiments by means of extensive system-level HSDPA simulations demonstrates that with the proposed TSP-based radio link buffer management schemes, significant end-to-end QoS performance gains accrue to end-user traffic with simultaneous RT and NRT flows, in addition to improved resource utilization in the radio access network.     

A new priority control of ATM output buffer

A new ATM output buffer management strategy with priority control function is proposed, based on four types of cell classes. This strategy can use system resource more effectively, meet the quality of service (QOS) requirements (i.e. cell loss probabilities and delay characteristics) of different services, and also can reduce the complexity of buffer. Furthermore, overload from lower priority traffic doesn't degrade the performance of higher priority traffic (i.e. cell loss rate and cell delay characteristics).     

Dynamic-Grouping bandwidth reservation scheme for multimedia wireless networks

In wireless networks carrying multimedia traffic (voice, video, data, and image), it becomes necessary to provide a quality-of-service(QoS) guarantee for multimedia traffic connections supported by the network. In order to provide mobile hosts with high QoS in the next-generation wireless networks, efficient and better bandwidth reservation schemes must be designed. This paper presents a novel dynamic-grouping bandwidth reservation scheme as a solution to support QoS guarantees in the next-generation wireless networks. The proposed scheme is based on the probabilistic resource estimation to provide QoS guarantees for multimedia traffic in wireless cellular networks. We establish several reservation time sections, called groups, according to the mobility information of mobile hosts of each base station. The amount of reserved bandwidth for each base station is dynamically adjusted for each reservation group. We use the dynamic-grouping bandwidth reservation scheme to reduce the connection blocking rate and connection dropping rate, while increasing the bandwidth utilization. The simulation results show that the dynamic-grouping bandwidth reservation scheme provides less connection-blocking rate and less connection-dropping rate and achieves high bandwidth utilization.     

Quality-Driven Capacity-Aware Resources Optimization Design for Ubiquitous Wireless Networks

In this paper, we propose a probability-statistical capacity-prediction scheme to provide probabilistic quality-of-service (QoS) guarantees under the high traffic load of IEEE 802.11 wireless multimedia Mesh networks. The proposed scheme perceives the state of wireless link based on the MAC retransmission statistics and calculates the statistical channel capacity especially under the saturated traffic load. Via a cross-layer design approach, the scheme allocates network resource and forwards data packets by taking the interference among flows and the channel capacity into consideration. Extensive experiments have been carried out on the basis of IEEE 802.11 protocols in order to demonstrate the superiority of the proposed scheme over the existing location-based QoS optimization delivery algorithm in terms of retransmission count, successful delivery rate, and end-to-end delay on the condition of time-varying multi-hop wireless links.     

QoS Provisioning with New Effective Bandwidth/Buffer Calculation Scheme in Wireless IP Networks

The huge commercial success of mobile telephony, the phenomenal growth of Internet users, the popularity of IP-based multimedia applications are the major driving forces behind third-generation (3G), ongoing Byond 3G (B3G), and forth-genertion (4G) evolution. 3G brought wired applications, both data and multimedia, into wireless environments. It operates on IP-based infrastructures to provide wider service access capability. To support and satisfy QoS (Quality of Service) of diverse IP-based multimedia applications, traffic management, such as Connection Admission Control (CAC) and resource allocation, becomes essential. CAC and resource allocation are computationally complex when combined with QoS guarantee for traffic with different characteristics. However, CAC and resource allocation are real-time traffic control procedures. Hence, processing load should be minimized to reduce delay. At the same time, network resources should be utilized efficiently to accommodate more users. However, reducing processing load and obtaining high resource utilization efficiency has been considered to be contradictory matter. In addition, CAC and resource allocation schemes which consider multiple QoS criteria – loss and delay – simultaneously have not been adequately studied. Simultaneous QoS consideration is important to satisfy stringent and diverse QoS requirements of multimedia traffic. In this paper, we propose a nobel effective bandwidth/buffer calculation method based on a virtual channel/buffer analysis scheme. We show that our method can achieve high resource utilization efficiency with reduced processing load. Moreover, we show that our scheme allows for simultaneous consideration of multiple QoS criteria, loss and delay.     

Dynamic resource allocation schemes during handoff for mobilemultimedia wireless networks

User mobility management is one of the important components of mobile multimedia systems. In a cell-based network, a mobile should be able to seamlessly obtain transmission resources after handoff to a new base station. This is essential for both service continuity and quality of service assurance. In this paper, we present strategies for accommodating continuous service to mobile users through estimating resource requirements of potential handoff connections. A diverse mix of heterogeneous traffic with diverse resource requirements is considered. The investigate static and dynamic resource allocation schemes. The dynamic scheme probabilistically estimates the potential number of connections that will be handed off from neighboring cells, for each class of traffic. The performance of these strategies in terms of connection blocking probabilities for handoff and local new connection requests are evaluated. The performance is also compared to a scheme previously proposed by Yu and Leung (see IEEE J. Select. Areas Commun., vol.15, p.1208-25, 1997). The results indicate that using dynamic estimation and allocation, we can significantly reduce the dropping probability for handoff connections     

Performance evaluation of the RQMA-CDMA scheme for multimedia traffic with QoS guarantees

The rapid growth of cellular mobile technology in recent years, coupled with the explosive growth of the Internet, has significantly increased the demand for wireless data services. Traffic on mobile devices is expected to be a mix of real-time traffic such as video, voice, and data, with users requiring diverse quality of service (QoS) guarantees for different types of traffic (video, voice and data). One of the primary challenges of providing QoS is how to prioritize and allocate network resources among contending applications. In order to achieve these goals, a scheduling scheme that can provide equitable and effective packet routing is required. This paper proposes a scheduling scheme called remote queuing multiple access-code division multiple access (RQMA-CDMA), whose purpose is to equitably assign bandwidth resources with QoS guarantees to different mobile devices. RQMA-CDMA is a rate scheduling scheme that can be used to assign bandwidth resources in conjunction with GPS (generalized processor sharing). Additionally, we analyze an admission control that is based on signal to interference plus noise ratio (SINR) for multimedia traffic. Finally, the performance of RQMA-CDMA is evaluated and compared to schemes based on CDMA-GPS according to dropped packets, delay, and throughput.     

Session-aware popularity-based resource allocation for assureddifferentiated services

Differentiated services networks are fair in the way that different types of traffic can be associated to different network services, and so to different quality levels. However, fairness among flows sharing the same service, may, not be provided. Our goal is to study fairness between scalable multimedia sessions for assured DS services in a multicast network environment. To achieve this goal, we present a fairness mechanism called session-aware popularity-based resource allocation (SAPRA), which allocates resources to scalable. sessions based on their number of receivers. Simulation results in a scalable and multireceiver scenario show that SAPRA maximizes the utilization, of bandwidth and the number of receivers with high-quality reception     

基于多种业务流资源共享的在线呼叫接入控制算法

本文针对多种业务类型提出了一种在线呼叫接入控制算法（OCAC）。OCAC算法是基于QoS业务量的服务质量要求和BE业务量的拥塞状态来动态地调整资源的分配,目的是更有效地利用资源并且在QoS业务流调整服务质量的同时,改善BE业务量的吞吐量。针对多跳的情况,本文描述了OCAC算法的两种实现方案,即基于每个节点和基于源节点的OCAC实现方案（ENS和SNS）。最后给出了仿真结果,并对本文提出的算法和静态接入控制算法的仿真结果进行了比较,进一步说明OCAC算法的有效性。     

Priority assignment control of ATM line buffers with multiple QOSclasses

In an asynchronous transfer mode (ATM) network multimedia environment, the bandwidth efficiency can be improved by defining multiple quality of service (QOS) classes and using a traffic control which manages required QOS of each class individually (QOS control). Priority assignment control is presented as a QOS control method in an ATM switching node. To quantitatively evaluate the control performance, the region determined by the offered load of each class where the QOS requirements of all the classes are satisfied is analytically obtained and various combinations of two classes and related control effects are discussed. When required values of cell loss rate and delay time are both different between the classes, the control effect is large; however, when only either of them is different, the effect is relatively small. The control scheme to enlarge the actual admissible offer load region by adaptively changing the priority assignment ratio is presented and its feasibility is confirmed by the simulation