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.     

Enhanced Dynamic Bandwidth Allocation Algorithm in Ethernet Passive Optical Networks

As broadband access is evolving from digital subscriber lines to optical access networks, Ethernet passive optical networks (EPONs) are considered a promising solution for next generation broadband access. The point‐to‐multipoint topology of EPONs requires a time‐division multiple access MAC protocol for upstream transmission. In this paper, we propose a new enhanced dynamic bandwidth allocation algorithm with fairness called EFDBA for multiple services over EPONs. The proposed algorithm is composed of a fairness counter controller and a fairness system buffer in the optical line terminal. The EFDBA algorithm with fairness can provide increased capability and efficient resource allocation in an EPON system. In the proposed EFDBA algorithm, the optical line termination allocates bandwidth to the optical network units in proportion to the fairness weighting counter number associated with their class and queue length. The proposed algorithm provides efficient resource utilization by reducing the unused remaining bandwidth made by idle state optical network units.     

Ethernet passive optical network (EPON): building a next-generationoptical access network

This article describes Ethernet passive optical networks, an emerging local subscriber access architecture that combines low-cost point-to-multipoint fiber infrastructure with Ethernet. EPONs are designed to carry Ethernet frames at standard Ethernet rates. An EPON uses a single trunk fiber that extends from a central office to a passive optical splitter, which then fans out to multiple optical drop fibers connected to subscriber nodes. Other than the end terminating equipment, no component in the network requires electrical power, hence the term passive. Local carriers have long been interested in passive optical networks for the benefits they offer: minimal fiber infrastructure and no powering requirement in the outside plant. With Ethernet now emerging as the protocol of choice for carrying IP traffic in metro and access networks, EPON has emerged as a potential optimized architecture for fiber to the building and fiber to the home     

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.     

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.      

PON with Automatic Protection switching for high reliable communication

PON (Passive Optical Network) permits the economical deployment of FTTH (Fiber to the Home) networks by sharing a single optical subscriber line among multiple subscribers. Especially since 2002, the deployment of PON systems has grown rapidly. This paper introduces the current status of FTTH in Japan then proposes a redundant optical access system with APS (Automatic Protection Switching) over PON which enables PONs for FTTBus (Fiber to the Business).     

QoS-aware Two-level Dynamic Uplink Bandwidth Allocation Algorithms in IEEE 802.16j Based Vehicular Networks

Wireless communications play an important role in improving transportation environment safety and providing Internet access for vehicles. This paper proposes a QoS-aware two-level uplink dynamic bandwidth allocation (DBA) algorithm for IEEE 802.16j-based vehicular networks. IEEE 802.16j is an extension of standard IEEE 802.16 to support relay mode operation where traffics from/to subscriber stations (SS) are relayed to/from a base station (BS) via a relay station (RS). In such a vehicular network, the IEEE 802.16j BSs are installed along a highway, RSs are installed in large vehicles such as coaches, and the 802.16j interface is equipped on SSs such as individual passengers’ mobile devices within a moving coach. In the proposed DBA algorithm, a utility function, which considers characteristics of different types of services, is designed. The objective of the proposed two-level DBA algorithm is to allocate bandwidth to different types of services from BS to RSs and then from a RS to SSs with given quality of service (QoS) requirements. It aims at maximizing the utility of the overall network and minimizing the average queuing delay of the overall network. The simulation results show the effectiveness and efficiency of the proposed DBA algorithm.     

Software-defined dynamic bandwidth optimization (SD-DBO) algorithm for optical access and aggregation networks

The optical access networks and aggregation networks are necessary to be controlled together to improve the bandwidth resource availability globally. Unified control architecture for optical access networks and aggregation networks is designed based on software-defined networking controller, the function modules of which have been described and the related extended protocol solution has been given. A software-defined dynamic bandwidth optimization (SD-DBO) algorithm is first proposed for optical access and aggregation networks, which can support unified optimizations and efficient scheduling by allocating bandwidth resources from a global network view in real time. The performance of the proposed algorithm has been verified and compared with traditional DBA algorithm in terms of resource utilization rate and average delay time. Simulation result shows that SD-DBO algorithm performs better.     

Jitter performance in ethernet passive optical networks

Ethernet passive optical networks (EPONs) have emerged as one of the most promising access network technologies. Propelled by rapid price declines in fiber optics and Ethernet components, these architectures combine the latest in optical and electronic advances and are poised to become the dominant means of delivering gigabit broadband connectivity to homes over a unified single platform. As this technology matures, related quality of service (QoS) issues are becoming a key concern. This paper proposes a novel dynamic scheduling algorithm, termed hybrid granting protocol (HGP), to support different QoS in EPON. Specifically, the proposed dynamic scheduling algorithm minimizes packet delay and jitter for delay and delay-variation sensitive traffic (e.g., voice transmissions) by allocating bandwidth in a grant-before-report (GBR) fashion. This considerably improves their performance without degrading QoS guarantees for other service types. Detailed simulation experiments are presented to validate the effectiveness of the proposed algorithm.     

Novel wavelength and bandwidth allocation algorithms for WDM EPON with QoS support

Ethernet passive optical networks (EPONs) have been considered as the one of the most promising candidates for next-generation access networks. However, the EPON architecture although cost effective is bandwidth limited and quality of service (QoS) support is still a major concern. In this paper, we propose a cost-efficient wavelength division multiplexing (WDM) EPON architecture. We present two wavelength and bandwidth allocation algorithms with full QoS support to fulfill all requirements of new application and services in a converged triple play network. We analyze and compare the presented models and algorithms in terms of delay, jitter, queue occupancy, throughput and overall system performance. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed architecture and algorithms.     

GPON中一种基于带宽需求的带宽分配算法

吉比特无源光网络（GPON）是接入网的最新发展趋势，动态带宽分配对提高GPON的服务质量、改进GPON系统时延及信道利用率等性能指标有着重要的意义，是GPON系统的关键技术之一，主要对GPON上行信道动态带宽分配技术进行研究，在分析GPON基于业务和基于T—CONT两种动态带宽分配算法的基础上提出一种新的改进型算法，新算法具有高效率和保证QoS的优点，并分析了这种算法的性能。     

DWDM-based FTTC access network

This paper proposes a dense wavelength division multiplexing (DWDM)-based fiber-to-the-curb (FTTC) access network architecture for broad-band services. The reaches of four carrierless amplitude phase (4-CAP)-modulated very high-speed digital subscriber line (VDSL) signals over the hybrid-fiber twisted pair (HFTP) were simulated. The simulation results show that the effect of noise from the optical link is negligible as long as the signal-to-noise ratio (SNR) of the optical link output signal is 9-10 dB greater than the required SNR of a VDSL modem. The bit error rate (BER) of the VDSL transmission over HFTP was measured. Measurement results show that insertion of the optical link between the modem and twisted pair has no adverse effect on the transmission     

Research on Convergence Network of EPON and WiMAX Based on ROF

Convergence of optical and wireless networks is a promising development for future access network architecture. A Radio over Fiber (ROF)-based network that converges Ethernet Passive Optical Network (EPON) and Worldwide Interoperability for Microwave Access (WiMAX) technologies makes it possible to simultaneously transmit EPON baseband signals and WiMAX wireless Radio Frequency (RF) signals. This article elaborates on uplink and downlink transmission, redundancy protection, and roaming features of such a network.     

Review on Dynamic Bandwidth Allocation of GPON and EPON

The passive optical network (PON) technology has been drastically improved in recent years. In spite of using the optical technology, the utilization of the entire bandwidth is a very challenging task. The main categories of PON are the Ethernet passive optical network (EPON) and gigabit passive optical network (GPON). These two networks use the dynamic bandwidth allocation (DBA) algorithm to attain the maximum usage of bandwidth, which is provided in the network dynamically according to the need of the customers with the support of the service level agreement (SLA). This paper will provide a clear review about the DBA algorithm of both technologies as well as the comparison.     

A Queuing Theory-Enabled Dynamic Bandwidth Allocation Algorithm for a Wired-Wireless Converged Network

Multi-sink wireless sensor networks (WSNs) are being increasingly deployed in an ever-widening range of application scenarios, especially as they are reliable and exhibit low power consumption. Providing a backhaul for WSN traffic has become an important issue because the sensor data must usually be sent to the Internet or the core network. Passive optical networks (PONs) represent one next-generation access network technology which is appropriate for such a backhaul, however existing research appears to have concentrated on either WSN performance or PON performance, without considering the overall performance of both networks converged together. This paper proposes a new architecture which converges multi-sink WSNs and PONs, then provides a novel queuing-theory analysis of the converged network performance. Results from this analytical model are then used to motivate a new a DBA algorithm which optimizes grant size allocation. Numerical results show that this algorithm outperforms existing proposals when minimizing the system queue length in the converged network, while providing shorter end-to-end packet delay and higher throughput. We believe that this first resource allocation algorithm which considers the performance of both networks as one converged unit.     

以太无源光网络的系统设计

EPON(Ethernet over Passive Optical Network,以太无源光网络)是一种新型的光纤接入网技术,它采用点到多点结构、无源光网络传输,在以太网之上提供多种业务。主要研究EPON网络系统的设计和实现,以及EPON的网络结构特点,通过逻辑分析与实证相结合的办法,论述了EPON网的设计过程,得出了不同接入需求下的设计方案。创新之处在于从用户带宽需求入手实现资源配置最优的效果。     

A novel all-optical transport network with time-shared wavelength channels

High-speed and high-capacity transport networks are necessary for providing future broadband services and multimedia applications. Optical networks, such as wavelength-routed networks and optical switching networks, are the most popular solutions. However, the limited electronic switching capability constrains the scalability of the multihop wavelength routed networks, while the difficulty and complexity of implementing efficient optical buffers and optical contention resolution schemes constrains the development of optical switching networks. This paper proposes a new architecture for the optical transport networks based on time-wavelength-space routers (TWSRs). The TWSR is equipped without optical buffers and optical contention resolution devices. A connection is established by constructing a time-slot based lightpath (ts-lightpath) between source TWSR and destination TWSR. The paper also proposes a heuristic algorithm for the problem of establishing the set of efficient ts-lightpaths for a given set of connection requests. The effectiveness of the proposed network architecture with the heuristic algorithm is demonstrated by simulation.     

A Weighted Scheduling Mechanism to Reduce Multicast Packet Loss in IPTV Service over EPON

This letter proposes a weighted scheduling mechanism for Internet protocol television (IPTV) to improve the loss performance of multicast transmission over an Ethernet passive optical network (EPON). We propose a new weight policy from the number of multicast receivers to proportionally allocate the downstream bandwidth of IPTV traffic. The proposed mechanism is used in an optical line terminal to decrease lost packets of favorite IPTV services because the lost multicast packets are proportional to the number of receivers. The total proportion of lost multicast packets is reduced by up to 73% in an EPON.     

A study of quality of service in the universal DBA algorithm using a PIC-based EPON testbed

Ethernet Passive Optical Network (EPON) has emerged as a promising technology since it offers high bandwidth at a distance that can go up to 20 km. In the upstream EPON transmission, a dynamic bandwidth allocation (DBA) algorithm is needed to avoid collisions and to efficiently allocate the bandwidth. This paper proposes an algorithm called as a Universal DBA (UDBA) algorithm that can support the priority universally in the entire EPON system. A peripheral interface controller (PIC)-based EPON testbed is used to test the algorithm within the mulipoint control protocol environment. For the performance study, we have compared the results achieved using UDBA in terms of delay, throughput, and fairness with two other DBA algorithms. UDBA shows improvements in terms of expedited forwarding, assured forwarding and best effort delay as much as 43.9, 42.6, 20 % over User-oriented Hierarchical Bandwidth Scheduling with Single Cycle (UHSA-S) and 37.5, 20.2, 25.3 % over Modified Smallest Available Report First (MSARF), respectively. Throughput is improved as high as 17.9 % over UHSA-S and 12.8 % over MSARF. In addition, the fairness index of UDBA is higher up to 14 % as compared to UHSA-S and 2.7 % as compared to MSARF.     

EPON系统动态带宽管理技术及测试方法

光接入网方兴未艾,作为现阶段我国采用的主要光接入技术手段——基于以太网的无源光网络（EPON）正处于大规模商用阶段。在多用户和多业务的环境中,系统的带宽有效管理技术变得至关重要。目前EPON中所使用的动态带宽分配基本上都是基于请求一授权的分配方式,如何评测某种动态带宽分配（DBA）算法的效率成为测试领域的新课题。一个完整的测试方案需包括：测试参考点的选取,测试参考模型的搭建,测试步骤的确立以及结果分析等。