一种新的EPON动态带宽分配方法的研究

传统的EPON系统的上行带宽分配方案是类似于IPACT的基于时隙长度分配的,这样虽然使上行信道得到了充分的利用,但是由于包延迟变化较大,不适合实时业务的传送.介绍了一种混合时隙长度/速率DBA方案,它可以为不同业务提供不同的QoS,既满足了实时业务的需要,又在一定程度上提升了网络的利用率.     

IPACT With Grant Estimation (IPACT-GE) Scheme for Ethernet Passive Optical Networks

Dynamic bandwidth allocation (DBA) is an open and hot topic in the Ethernet passive optical network (EPON), which is regarded as one of the best choices for next-generation access networks. This paper proposes an estimation-based scheme, interleaved polling with adaptive cycle time with grant estimation (IPACT-GE), for effective upstream channel sharing among multiple optical network units (ONUs) in EPONs. By estimating the amount of new packets arriving between two consecutive pollings and granting ONUs with extra estimated amount, the proposed IPACT-GE scheme can achieve shorter waiting delay and less buffer occupancy at the light load than IPACT, a significant DBA scheme in EPONs. Moreover, when combined with the strict priority queue (SPQ) mechanism to provide differentiated services, IPACT-GE can greatly mitigate the light load penalty that is obvious in the IPACT solution combined with SPQ.      

一种支持多用户SLA的EPON上行带宽分配算法设计

在接入网服务等级协定的基础上,分析了以IPACT和CyclicDBA为代表的EPON上行动态带宽分配算法,讨论了其对EPON上多用户SLA支持所存在的固有缺陷。提出了适合SLA应用的EPON控制帧结构:授权帧和请求帧。根据这两种控制帧,设计了一种新型的支持多用户SLA的EPON上行信道带宽分配算法,等级轮询固定周期算法。通过理论分析和计算机仿真测试表明该算法针对EPON不同类型的接入用户均达到了较理想的性能指标,高优先级业务良好的时延和时延抖动特性,各种业务队列的尺度平稳,同时HPFCT还解决了传统轮询算法中低负载时下行带宽浪费明显的问题。     

A Novel Dynamic Bandwidth Assignment Algorithm for Multi-Services EPONs

1IntroductionIt seems that providing broadband services is thesaver of telecom industry. Long-haul and Metro corenetworks are capable of carrying broadband servicessince they have experienced a dramatic i mprovement inbandwidth capacity and efficiency with the advent oftechnologies such as Dense Wave length Division Multi-plexing (DWDM)[1 ~3]and other newtechnologies .Buta clear bottleneckexistsinthe“first mile”of access net-work[4]. Without eli minationthe bandwidth bottlenecksthat exis…     

基于QoS的EPON系统动态带宽分配机制

通过阐述以太网无源光网络（EPON）系统信道传输数据方式以及动态带宽分配的工作原理,进一步研究了动态带宽分配算法（DBA）在EPON系统中的应用。提出一种基于服务质量（QoS）的EPON系统动态带宽分配机制,该机制根据不同业务的优先级和动态带宽分配算法,灵活地分配上行带宽,提高了带宽利用率,改善了服务质量。     

低成本多业务综合接入EPON系统设计方案研究

EPON是实现KTTH理想的技术之一,在EPON上同时传输多种宽带业务目前面临着Qos、DBA、高带宽、安全性、成本等诸多挑战.业界领先的EPON芯片供应商Teknovus的EPON SoC为开发低成本多业务综合接人EPON系统提供了良好的解决方案,势必进一步推动EPON技术的发展.     

Resources allocation in an Intserv/Diffserv integrated EPON system

As one of the most promising next-generation access network techniques, the user-oriented Ethemet passive optical network (EPON) should pay more attention to its quality of service (QoS). However, now the EPON adopts mostly differentiated services model (Diffserv) that only provides quality control on traffic aggregation, whereas, the quality of user session cannot be guaranteed when the network is overloaded with substantial connections. This article proposes to apply integrated services model (lntserv) in Diffserv-based EPON, which uses per-flow processing to guarantee QoS. In the simulation, a framework of combined Diffserv and lntserv model is employed in an EPON system, with a dynamic bandwidth allocation algorithm that adapts to it. The simulation results demonstrate that the EPON system with the combined models can provide more flexible, various control for user-oriented service quality.     

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.     

Analysis of Radio Resource Allocation in LTE Uplink

Long term evolution (LTE) uses orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC-FDMA) as the downlink and uplink transmission schemes respectively. The Quality of Service (QoS) provision to users is one of the key objectives of the wireless network operators. This paper analyses an uplink LTE radio scheduler, called bandwidth and QoS aware (BQA) scheduler and evaluates its QoS performance. The BQA uplink scheduler is designed to provide efficient and fair allocation of the radio resources to users according to: the QoS of various traffic classes and the instantaneous channel conditions. The scheduler functionality is divided into time domain packet scheduling (TDPS) and frequency domain packet scheduling (FDPS). In this paper, an innovative feature, that is user QoS provisioning with dynamic QoS weights, is employed for the BQA scheduler along with multi-bearer users support. The QoS performance of the BQA scheduler is analyzed in several simulation scenarios using heterogeneous traffic environment. The results show that the BQA scheduler guarantees provision of QoS to users.     

Using traffic prediction and estimation of provider revenue for a joint GEO satellite MAC/CAC scheme

Satellite networks present an attractive solution in providing worldwide access to the present and future generation multimedia communication services. However, the burstiness of multimedia traffic and the long propagation delays in Geostationary (GEO) satellite systems call for an efficient Medium Access Control (MAC) protocol and an equally efficient Call Admission Control (CAC) scheme, in order to provide acceptable Quality of Service (QoS) to multimedia users. This paper proposes a fair and dynamic CAC and MAC framework, named Fair Predictive Resource Reservation Access (FPRRA), which is based on accurate videoconference traffic prediction and makes decisions after taking into account the provider revenue. The framework’s performance is evaluated in comparison to other efficient schemes from the literature.     

EPON和WiMAX融合架构下带宽分配和调度机制的研究

以太网无源光网络(EPON)和IEEE 802.16(WiMAX)的融合网络在固定移动混合接入网中被认为是很有前景的接入方式.文中提出了3种WiMAX无线网络与EPON网络系统融合架构,融合系统同时具有光网络的高带宽和无线网络的灵活性.为了在接入网中支持QoS,本文为融合结构提出了一种动态带宽分配算法(DBA)和调度机...     

Dynamic bandwidth allocation for quality-of-service over Ethernet PONs

Ethernet-based passive optical network (EPON) technology is being considered as a promising solution for next-generation broadband access networks due to the convergence of low-cost Ethernet equipment and low-cost fiber infrastructures. A major feature for this new architecture is the use of a shared transmission media between all users; hence, medium access control arbitration mechanisms are essential for the successful implementation of EPON: i.e., to ensure a contention-free transmission and provide end users with equal access to the shared media. We propose to use the multipoint control protocol defined by the IEEE 802.3ah task force to arbitrate the transmission of different users, and we present different dynamic bandwidth allocation (DBA) algorithms to allocate bandwidths effectively and fairly between end users. These DBA algorithms are also augmented to support differentiated services, a crucial requirement for a converged broadband access network with heterogeneous traffic. We show that queueing delays under strict bandwidth allocation algorithms result in an unexpected behavior for certain traffic classes, and we suggest the use of DBA with appropriate local queue management to alleviate this inappropriate behavior. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed protocols.     

Convergence of ethernet PON and IEEE 802.16 broadband access networks and its QoS-aware dynamic bandwidth allocation scheme

IEEE 802.16 and Ethernet Passive Optical Network (EPON) are two promising broadband access technologies for high-capacity wireless access networks and wired access networks, respectively. They each can be deployed to facilitate connection between the end users and the Internet but each of them suffers from some drawbacks if operating separately. To combine the bandwidth advantage of optical networks with the mobility feature of wireless communications, we propose a convergence of EPON and 802.16 networks in this paper. First, this paper starts with presenting the converged network architecture and especially the concept of virtual ONU-BS (VOB). Then, it identifies some unique research issues in this converged network. Second, the paper investigates a dynamic bandwidth allocation (DBA) scheme and its closely associated research issues. This DBA scheme takes into consideration the specific features of the converged network to enable a smooth data transmission across optical and wireless networks, and an end-toend differentiated service to user traffics of diverse QoS (Quality of Service) requirements. This QoS-aware DBA scheme supports bandwidth fairness at the VOB level and class-of-service fairness at the 802.16 subscriber station level. The simulation results show that the proposed DBA scheme operates effectively and efficiently in terms of network throughput, average/maximum delay, resource utilization, service differentiation, etc.     

一种保证EPON中DBA公平性的算法

动态带宽分配是以太网无源光网络(EPON)系统的一个重要研究领域,文章提出一种在EPON系统中保证动态带宽分配公平性的新型算法.该算法计算量适中, 同时兼顾了动态带宽分配的效率和公平性.文中通过推导给出了最优算法,并在模拟流量下进行了仿真,通过与已有算法的对比,证明其有很好的性能.     

优化EPON对本地P2P业务承载能力的研究

P2P流量已成为网络中的主要流量,但现有EPON系统不能很好的承载本地P2P业务.文中从MPCP协议的角度对逻辑链路标签及其过滤规则进行扩展,使本地P2P数据包不需经OLT端二层交换即可实现下行转发,从而大大改善了P2P业务的QoS.并以此方案为基础,提出改进EPON的DBA算法,设置专门的P2P时隙,实现P2P业务的全光域转发.两种方案的建模仿真结果表明,两者均能明显改善EPON对本地P2P业务的承载能力.     

Cost models for QoS-differentiated interconnecting and wholesale access services in?future generation networks

Currently, network operators and Internet service providers are offering ??Triple Play?? products integrating services with different Quality of Service (QoS) requirements. It is leading to Internet traffic with strong service integration under an all-IP-based broadband network platform. However, new multimedia service offers require individual QoS guarantees for each type of services. The interconnection between different providers necessitates the reconsideration of the actual cost schemes. Interconnection and wholesale access services (It is an extension of ??wholesale network?? definition, where Telco??s physical network and equipment are ??shared?? to many independent Service Providers. If the incumbent offers broadband access services, the rest of the alternative providers have recourse to the incumbent??s ??wholesale access service??. Bitstream service is the most important service of this type, actually regulated over DSL and cable networks.) appear to be a simple solution, but the consideration of QoS parameters requires an extension of the current network dimensioning methods based mainly on the average bandwidth demand from each user. This paper proposes a cost model which considers QoS parameters and, based on the ??Total Element based Long Run Incremental Cost?? (TELRIC) model, is applied to the wholesale access and interconnection paradigm. Three traffic engineering methods are considered and studied for network dimensioning. Hereby the aim is to guarantee the QoS of the different services: complete traffic segregation under virtual tunnels, complete traffic integration by over-engineering and partial traffic integration using a priority queuing scheme. The proposed method enables the development of a specific cost scheme based on a complete scenario considering different types of users. The variety of used IP applications suppose direct implications over different levels of interconnection, mainly at the low-level Metro access and the high-level edge node.     

Performance analysis of the IEEE 802.11e wireless networks with TCP ACK prioritization

With the advent of multimedia over wireless local area networks, the IEEE 802.11e standard was proposed to incorporate Quality of Service (QoS). It has been found that the throughput of Transmission Control Protocol (TCP) is less than that of User Datagram Protocol (UDP) in the IEEE 802.11e. This is because the TCP acknowledgment packets are queued up at the access points. In this paper, two types of TCP acknowledgment prioritizing schemes are proposed. The proposed schemes improve the overall throughput of TCP while maintaining the QoS requirements. We also analyze the problem of starvation of lower priority traffic and its effects on the performance of lower priority TCP traffic. The proposed dynamic scheme of TCP acknowledgment prioritization aims at improving the throughput of the lower priority TCP traffic under heavy network load while maintaining the QoS requirements of the higher priority traffic. The schemes have been verified through extensive simulation.     

Block Reservation Time Division Multiple Access (BRTDMA) Protocol for a High Capacity Wireless Network

Next generation high capacity wireless networks need to support various types of traffic, including voice, video and data, each of which have different Quality of Service (QoS) requirements for successful transmission. This paper presents an advanced reservation packet access protocol BRTDMA (Block Reservation Time Division Multiple Access) that can accommodate voice and data traffic with equal efficiency in a wireless network. The proposed BRTDMA protocol has been designed to operate in a dynamic fashion by allocating resources according to the QoS criteria of voice and data traffic. Most of the existing reservation protocols offers reservation to voice traffic while data packets are transmitted using contention mode. In this paper we propose a block reservation technique to reserve transmission slots for data traffic for a short duration, which minimizes the speech packet loss and reduce the end-to-end delay for wireless data traffic. The optimum block reservation length for data traffic has been studied in a cellular mobile radio environment using a simulation model. Simulation results show that the BRTDMA protocol offers higher traffic capacity than standard PRMA protocol for integrated voice and data traffic and offers flexibility in accommodating multimedia traffic.     

Fair Class-Based Downlink Scheduling with Revenue Considerations in Next Generation Broadband Wireless Access Systems

The success of emerging Broadband Wireless Access Systems (BWASs) will depend, among other factors, on their ability to manage their shared wireless resources in the most efficient way. This is a complex task due to the heterogeneous nature, and hence, diverse Quality of Service (QoS) requirements of different applications that these systems support. Therefore, QoS provisioning is crucial for the success of such wireless access systems. In this paper, we propose a novel downlink packet scheduling scheme for QoS provisioning in BWASs. The proposed scheme employs practical economic models through the use of novel utility and opportunity cost functions to simultaneously satisfy the diverse QoS requirements of mobile users and maximize the revenues of network operators. Unlike existing schemes, the proposed scheme is general and can support multiple QoS classes with users having different QoS and traffic demands. To demonstrate its generality, we show how the utility function can be used to support three different types of traffic, namely best-effort traffic, traffic with minimum data rate requirements, and traffic with maximum packet delay requirements. Extensive performance analysis is carried out to show the effectiveness and strengths of the proposed packet scheduling scheme.     

A comparison of dynamic bandwidth allocation for epon, gpon, and next-generation tdm pon - [topics in optical communications]

Dynamic bandwidth allocation in passive optical networks presents a key issue for providing efficient and fair utilization of the PON upstream bandwidth while supporting the QoS requirements of different traffic classes. In this article we compare the typical characteristics of DBA, such as bandwidth utilization, delay, and jitter at different traffic loads, within the two major standards for PONs, Ethernet PON and gigabit PON. A particular PON standard sets the framework for the operation of DBA and the limitations it faces. We illustrate these differences between EPON and GPON by means of simulations for the two standards. Moreover, we consider the evolution of both standards to their next-generation counterparts with the bit rate of 10 Gb/s and the implications to the DBA. A new simple GPON DBA algorithm is used to illustrate GPON performance. It is shown that the length of the polling cycle plays a crucial but different role for the operation of the DBA within the two standards. Moreover, only minor differences regarding DBA for current and next-generation PONs were found.