EPON系统的动态带宽分配算法的研究

在未来几年里，光网络已经为主宰接入网领域做好了准备。首先简单介绍了以太网无源光网络以及目前已经提出的不同的动态带宽分配算法，然后针对每个算法不同的特点与适用范围进行了性能分析和比较，最后对动态带宽算法未来的发展进行了展望。     

EPON系统中周期轮询动态带宽分配算法的改进

分析了CPFCT下周期间空闲时间的产生和由此导致的性能损失,论述了现有的解决方案及其缺点,提出两种分别基于EG机制和FR机制的改进算法,仿真结果显示两种算法在带宽利用率、时延等方面均实现了性能的提升.     

An approximate bandwidth allocation algorithm for tradeoff between fairness and throughput in WSN

Wireless Networks - In this paper, we investigate the problem of bandwidth allocation in wireless sensor network (WSN) under signal to noise plus interference ratio interference model, which aims...     

Architecture of multi-OLT PON systems and its bandwidth allocation algorithms

In this paper, we propose a novel passive optical network (PON) architecture that has multiple optical line terminals (OLTs). Unlike existing PONs where all ONUs are connected to a single OLT, the proposed multi-OLT PON allows subscribers to choose their own service providers from among multiple OLTs. Service companies and subscribers can make service level agreements (SLA) on the amount of bandwidth that each OLT or ONU requires. A new control protocol and bandwidth allocation algorithms appropriate in this new PON environments are suggested. For the downstream, a scheme to share the bandwidth among multiple OLTs is studied to maximize the total transmitted packets while guaranteeing each OLT’s SLA. A modified Limited Dynamic Bandwidth Allocation named mLimited scheme is also proposed for upstream transmission toward multiple OLTs, which maximizes the total upstream throughput while minimizing the delay of each ONU. Performances of the proposed PON architecture and algorithms are analyzed. A PON system with two OLTs and 16 ONUs is used in the analysis. Self-similar traffic reflecting current packet distribution is used in the packet generation. The results show that the proposed DBA schemes efficiently manage bandwidth even when the occurred traffic load is quite different from the reserved bandwidth. It is found that the proposed PON architecture is appropriate in supporting diverse services in future high-speed optical access network.     

EPON系统两层动态带宽分配算法的研究

介绍EPON的系统结构和一些关键技术,提出一种新的两层动态带宽分配算法,运用OPNET Mod-eler仿真工具,从带宽利用率和端到端时延两个方面进行仿真分析.结果表明,新动态带宽分配方案可以明显提高系统的带宽利用率,经过多次反复试验,对线性变量信用度值进行估计,初步确定可获得最佳带宽利用率的变量k=0.16.     

Energy-efficient bandwidth allocation in wireless networks: algorithms, analysis, and simulations

In this paper, we present a new energy-efficient bandwidth allocation scheme for wireless networks. First of all, we investigate the intrinsic relationship between the energy consumption and transmission rates of mobile terminals, in which transmission rate is determined through channel allocations. Then, we propose two schemes for connection admission control: victim selection algorithm (VSA) and beneficiary selection algorithm (BSA) with the intent to reduce energy consumption of each terminal. Moreover, we introduce an adjustment algorithm to statistically meet the demands for quality of service (QoS) during the resource allocation. The performance of the proposed schemes is evaluated with respect to energy consumption rate of each successfully transmitted bit, throughput and call blocking probabilities. An extensive analysis and simulation study is conducted for Poisson and self-similar, multi-class traffic.     

Ethernet passive optical network architectures and dynamic bandwidth allocation algorithms

We compile and classify the research work conducted for Ethernet passive optical networks. We examine PON architectures and dynamic bandwidth allocation algorithms. Our classifications provide meaningful and insightful presentations of the prior work on EPONs. The main branches of our classification of DBA are: grant sizing, grant scheduling, and optical network unit queue scheduling. We further examine the topics of QoS support, as well as fair bandwidth allocation. The presentation allows those interested in advancing EPON research to quickly understand what already was investigated and what requires further investigation. We summarize results where possible and explicitly point to future avenues of research.     

On achieving fairness and efficiency in high-speed shared medium access

Channel access has been an active research area for the past two decades. Several protocols have been proposed in the literature to utilize channel bandwidth efficiently. Some of the recently proposed protocols achieve a near-ideal channel utilization. However, the efficiency in utilization comes at the expense of certain unfairness in delay characteristics. A new channel-access protocol, called access mechanism for efficient sharing in broadcast medium networks (AMES-BM), is developed based on a deterministic binary tree-splitting technique to achieve efficient sharing of bandwidth. In AMES-BM, the stations are dynamically mapped to leaf nodes of a binary tree. The stations are then divided into smaller groups that mimic the behavior of an ideal transmission queue. Collisions are allowed to occur within these groups and are resolved using a variation of the conventional binary tree-splitting technique. The performance of AMES-BM is similar to that of a collision-based protocol under low loads and to that of a collision-free protocol under high loads. Besides achieving a near-optimal channel utilization, the proposed protocol also guarantees fairness with respect to delay for messages of varying lengths. The deterministic nature of the protocol makes it more attractive for real-time applications.     

Ethernet PONs: a survey of dynamic bandwidth allocation (DBA) algorithms

Optical networks are poised to dominate the access network space in coming years. Ethernet passive optical networks, which leverage the ubiquity of Ethernet at subscriber locations, seem destined for success in the optical access network. In this article we first provide a brief introduction to Ethernet passive optical networks, followed by a discussion of the problem of dynamic bandwidth allocation. We then introduce a framework for classifying dynamic bandwidth allocation schemes and provide a comprehensive survey of the dynamic bandwidth allocation methods proposed to date. We conclude with a side by side comparison of the schemes based on their most prominent characteristics, and outline future developments of dynamic bandwidth allocation schemes.     

Resource and power allocation for achieving rate fairness in D2D communications overlaying cellular networks

Wireless Networks - This paper presents a novel resource and power allocation scheme for device-to-device (D2D) communications overlaying cellular networks. The proposed scheme is implemented in...     

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.     

On the fairness of resource allocation in wireless mesh networks: a survey

This article presents a comprehensive survey of resource allocation techniques in Wireless Mesh Networks (WMNs). Wireless mesh networks have emerged as a key technology for next generation application specific multi-hop wireless networks. We analyze the state-of-the-art resource allocation schemes for WMNs, providing comprehensive taxonomy of the latest work and the future research trends in this field. In general, the resources that are available for WMNs include time, frequency, space, relays, and power. An efficient utilization of these resources can make the network more robust, reliable, and fair. We categorize the resource allocation into “radio” resource allocation, “physical” resource allocation, “utility” based resource optimization, and “cross layer” resource optimization. An ample review of resource allocation schemes within these categories is provided.     

A survey of dynamic bandwidth allocation algorithms for Ethernet Passive Optical Networks

Ethernet Passive Optical Network (EPON) has been widely considered as a promising technology for implementing the FTTx solutions to the “last mile” bandwidth bottleneck problem. Bandwidth allocation is one of the critical issues in the design of EPON systems. In an EPON system, multiple optical network units (ONUs) share a common upstream channel for data transmission. To efficiently utilize the limited bandwidth of the upstream channel, an EPON system must dynamically allocate the upstream bandwidth among multiple ONUs based on the instantaneous bandwidth demands and quality of service requirements of end users. This paper introduces the fundamental concepts on EPONs, discusses the major issues related to bandwidth allocation in EPON systems, and presents a survey of the state-of-the-art dynamic bandwidth allocation (DBA) algorithms for EPONs.     

基于轮询的EPON动态带宽分配算法

主要依据IEEE802.3ah标准,对EPON当中的动态带宽分配算法进行了探讨,尤其是对于基于轮询的可变周期的带宽分配算法(IPACT算法)进行了一些改进,又结合OPNET的网络仿真工具建立了网络仿真模型,并给出了仿真结果和结果分析.     

一种基于星上处理的卫星ATM网络动态带宽分配策略

本文提出了一种基于星上处理的卫星ATM网络的动态带宽分配方案,它通过对流量的估计动态申请带宽,卫星作为控制中心根据链路利用情况来分配带宽,仿真结果表明,相对于现有的的方法,它可以保持链路效率,提高业务的服务质量,同时这种方法对星上资源要求不高,易于实现。     

基于多重分形小波GPON带宽分配算法

当前吉比特无源光网络中动态带宽分配算法主要是基于轮询机制,该算法是OLT根据各个ONU发送请求带宽信息进行动态分配带宽,但该算法不能实时获取各个ONU的请求信息.由于GPON网络业务流量具有多重分形特性,因此可以通过多重分形小波对网络流量进行预测,得到ONU实时的带宽信息.文章将预测结果应用于GPON上行信道动态带宽分配,提出一种改进动态带宽分配算法.     

Two-level QoS-aware frame-based downlink resources allocation for RT/NRT services fairness in LTE networks

In LTE, bandwidth resources allocation became a huge burden to be handled, as both of RT and NRT traffic should be processed fairly to satisfy their diverse QoS requirements. To tackle this issue in particular, in this work, we propose a fairness-based resources allocation method named Frame-based Game Theory (FGT), which can be flexibly implemented as an upper level in LTE downlink MAC layer; before the PRBs allocation function. Basically, FGT aim is to allow involved classes with different QoS requirements to fairly gain a part of the available channel resources to transmit their flows. Adhere, on every LTE-frame, a cooperative game scenario is designed. Wherein, Shapley formula is used to distribute the available amount of data within RT and NRT traffic classes. Then, conforming to these assigned resources portions to each traffic class, PRBs allocation process is triggered every TTI for the selected flows. In this work, we adopted some of the recent PRBs allocation methods as a lower level scheduler in order to illustrate a complete idea of MAC layer scheduling functions, and also to effectively evaluate FGT performance. Simulation results on various scenarios show that, fairness index for flows from different classes is increased when FGT is considered. The results also conveyed outperforming QoS indices for FGT on RT and NRT service in terms of throughput, PLR, as well as cell spectrum efficiency.     

On the parallel simulation of fixed channel allocation algorithms

We present, in this paper, several channel allocation algorithms for use in cellular communications networks or mobile networks. The channel allocation algorithms make use of fixed allocation of channels and channel reorganization. The channel reorganization algorithms are used to free channels within a neighborhood of the cell in which the requesting call originates. The performance of these algorithms was evaluated via distributed simulation, making use of the Chandy–Misra–Bryant NULL message algorithm, on a BBN Butterfly multiprocessor. In addition to evaluating the performance of the channel allocation algorithms, we examine the efficiency of the NULL message algorithm as a tool for our simulations. The reason for making use of parallel simulation was to avoid the long simulation times and large memory consumption characteristic of sequential (uniprocessor) simulations. Our results indicate that our channel allocation algorithms performed efficiently. Upwards of 20% of the calls which were not initially connected by the borrowing schemes were connected after channel reorganization. The NULL message approach proved to be efficient when the message traffic was not extremely low.     

Adaptive allocation of resources and call admission control forwireless ATM using genetic algorithms

In wireless ATM-based networks, admission control is required to reserve resources in advance for calls requiring guaranteed services. In the case of a multimedia call, each of its substreams (i.e., video, audio, and data) has its own distinct quality of service (QoS) requirements (e.g., cell loss rate, delay, jitter, etc.). The network attempts to deliver the required QoS by allocating an appropriate amount of resources (e.g., bandwidth, buffers). The negotiated QoS requirements constitute a certain QoS level that remains fixed during the call (static allocation approach). Accordingly, the corresponding allocated resources also remain unchanged. We present and analyze an adaptive allocation of resources algorithm based on genetic algorithms. In contrast to the static approach, each substream declares a preset range of acceptable QoS levels (e.g., high, medium, low) instead of just a single one. As the availability of resources in the wireless network varies, the algorithm selects the best possible QoS level that each substream can obtain. In case of congestion, the algorithm attempts to free up some resources by degrading the QoS levels of the existing calls to lesser ones. This is done, however, under the constraint of achieving maximum utilization of the resources while simultaneously distributing them fairly among the calls. The degradation is limited to a minimum value predefined in a user-defined profile (UDP). Genetic algorithms have been used to solve the optimization problem. From the user perspective, the perception of the QoS degradation is very graceful and happens only during overload periods. The network services, on the other hand, are greatly enhanced due to the fact that the call blocking probability is significantly decreased. Simulation results demonstrate that the proposed algorithm performs well in terms of increasing the number of admitted calls while utilizing the available bandwidth fairly and effectively     

JMAWR: joint optimization of monitoring trail allocation and wavelength routing with limited monitoring resources

In all-optical networks, monitoring trail (m-trail) has long been proposed as an effective way for link failure localization. Previous works tried to minimize the number of used m-trails for localizing network-wide single link failures, and they all supposed that the monitoring resources were enough. However, failures are rare events and the traffic demand is increasing rapidly. The dedicated wavelengths for m-trails cannot be used to transmit data traffic, and some traffic demand may not be served during the peak period. Considering the operators prefer to serve customers’ demand as much as possible, if the resources allocated for m-trails are limited, more traffic will be carried. In this paper, we focus on the scenario where there are not enough resources for allocating m-trails. In this scenario, as only part of single link failures can be unambiguously localized, we aim to monitor the most valuable links, which carry more traffic demand, and minimize the maximum number of used wavelengths for traffic demand on the links which cannot be unambiguously localized. As we can also control the wavelength routing for traffic demand, we try to jointly optimize the m-trail allocation and wavelength routing. We first formulate this joint optimization problem as a mathematical model and present concrete analyses on this model. According to these analyses, a joint m-trail allocation and wavelength routing (JMAWR) heuristic algorithm is proposed based on graph-constrained group testing. Simulation results show that JMAWR outperforms the state-of-the-art m-trail allocation algorithm by up to 88.46% improvement in terms of maximum number of used wavelengths for traffic demand on links which cannot be unambiguously localized.