Layered bandwidth allocation algorithm for multi-service in orthogonal frequency division multiplexing passive optical network

Due to the superiority in large bandwidth capacity and flexible resource allocation,orthogonal frequency division multiplexing passive optical network (OFDM-PON) has been recognized as one of the promising candidates for the next generation PON.There are many research works on the system architecture design of OFDM-PON.However,most of these works focused on the techniques of physical structure and signal transmission and less addressed the bandwidth allocation algorithms supporting the new types of system architecture.The bandwidth allocation in OFDM-PON,which is one of the key techniques to enable the access of multi-service,refers to the joint optimization of multi-dimensional resources in time domain,frequency domain and bits.A layered bandwidth allocation algorithm was proposed for multi-service in the enhanced system architecture of OFDM-PON,aiming at the efficient bandwidth resource utilization.Simulation results prove that the proposed bandwidth allocation algorithm outperforms the conventional algorithms without layered transmission significantly in terms of resource utilization and packet delay.     

星上MF-TDMA系统信道管理方法

MF-TDMA被广泛应用于现代宽带通信卫星系统的上行链路设计中,而时隙分配算法是系统资源利用率的重要保证。针对MF-TDMA时隙分配复杂,时隙资源浪费严重等难题,该文给出一种可动态调整载波信道的MF-TDMA系统时隙分配算法,算法将天基移动通信系统用户接入时隙分配问题分解为载波确定和载波内时隙分配两个部分,并针对用户终端载波确定问题,给出一种带载波调整的RCP算法(RCP-A)算法,解决现有方法在多业务多用户条件下资源浪费大、使用率低的问题;针对载波内时隙分配问题,采用基于倒序时隙编号时隙资源树管理方式,解决业务因时隙分配而带来的时延抖动问题;并给出了适合星上处理能力的时隙资源管理其实现方法。仿真测试显示,该实现方法适合于星上MF-TDMA无线资源管理器。     

MF-TDMA技术卫星应用探讨

多频时分多址(MF-TDMA)技术在卫星通信灵活组网和支持综合业务传输方面具有明显的优势,适合不同规模卫星通信网络的应用。MF-TDMA技术由于工作在突发模式,且时隙资源的分配存在一定的滞后性,在实际应用中,必须合理设计网络工作方式和系统参数,以提高MF-TDMA卫星通信网络的使用效率。在简要分析MF-TDMA工作模式的基础上,针对主要系统参数的选择进行了初步设计,给出了具体的应用范例。     

Simulation and analysis of software defined cognitive frequency hopping multi beam satellite system

Traditional multi-beam satellites cannot adapt to the changing traffic because of the fixed bandwidth and cannot adjust dynamically for the traffic load.In the future,the multi-beam broadband satellite system must have great flexibility and can be dynamically adjusted according to the change of the traffic flow.Beam hopping for multi-beam broadband satellite network system has been proposed to improve the traditional multi-beam broadband satellite network system performance,whose principle is to assign different beams to different time slots,rather than the allocation of bandwidth,so that in each time slot,the entire available bandwidth is allocated to each beam,and the time window is periodically applied to the beam selection system ,in the full band hopping mode,the band can be selected optimally in the duration of each beam to meet user transmission bandwidth and delay requirements.With the development of cognitive radio technology,cognitive beam hopping for multi-beam satellite system can further improve the efficiency of spectrum utilization,to meet the growing shortage of spectrum resources,to achieve large-capacity high-bandwidth broadband satellite network system,and to support the rising user service capacity and the transmission efficiency of user services under different load conditions.In addition,software definition technology is also used in satellite networks,which could achieve effective management of satellite resources to improve the utilization of satellite resources.In this paper,the principle of software-defined cognitive hopping multi-beam broadband satellite network system is discussed.The spectrum utilization efficiency and throughput are analyzed,which can be used as a reference for broadband satellite network system design.     

Spectrum allocation method for cognitive satellite network based on service priorities

By using spectrum allocation technology of cognitive radio into integrated satellite and terrestrial networks,the satellite communication network can share spectrum with the terrestrial network and improve utilization efficiency of frequency spectrum in the satellite communication system.Firstly,a spectrum resource sharing model in integrated satellite and terrestrial networks was introduced,and the scenery that cognitive satellite downlinks use the vacant spectrum of terrestrial network was analyzed.Then,the interference and signal model was analyzed.Finally,considering different priority types of satellite terrestrial terminals,a spectrum allocation scheme based on priority was proposed,which could ensure the total throughput in satellite downlink communication and increase the throughput of high-priority terrestrial terminals.     

Satellite constellation of MEO and IGSO network routing with dynamic grouping

Because inter‐satellite links (ISLs) among the distributed satellite nodes can be used to support autonomous control in satellite system operation to reduce dependency on the ground stations, it becomes a popular communication paradigm for the future satellite systems. However, this introduces great technical challenges, particularly for routing protocol to support such space communication system. Facing the challenges, we present out study of routing technology in this paper tailored for satellite network of MEO (Table 1) and IGSO with ISLs in addition to satellite–ground links. The study aims to explore the routing strategies and algorithms of satellite network based on the evolution law of network topology to provide reference design for data exchange in autonomous satellite system. A comprehensive investigation, ranging from the analysis of relevant factors affecting data exchange in satellite networks to the primary application and resource constraints in designing satellite routing strategy, has been conducted. Our main contribution is to propose an on‐demand computing and caching centralized routing strategy and algorithm on the satellite network. The routing strategy and algorithm is designed for satellite network topology dynamic grouping. The route calculation for user data transmission is divided into three phases: direction estimation, direction enhancement, and congestion avoidance. The strategy and algorithm provide significant advantages of high efficiency, low complexity, and flexible configuration, by which the satellite networks can provide the features of flexible configure, efficient transferring, easy management, structural survivability, and great potential in scalability. Copyright © 2013 John Wiley & Sons, Ltd.     

CDMA蜂窝移动通信系统中基于Eb/No的无线分组公平调度算法

在第三代移动通信的无线资源管理机制中,分组调度机制在保证预期的服务质量（QoS）和优化无线资源的利用率方面起到了至关重要的作用.至今已经有很多的调度算法被提出,用来有效地提高无线网络资源的利用率.本文提出一种基于Eb/No并且利用功率控制和管理机制的无线分组公平调度算法用来保证QoS,优化资源配置并且达到调度公平性.     

A new satellite communication bandwidth allocation combined services model and network performance optimization

With the rapid development of online to offline economy, new services compositions would take up a great part in the satellite communication. More and more new services compositions request more bandwidth and network resources, which lead to serious traffic congestion and low channel utilization. Suffering from isolated link connection and changeable delay under the satellite environment, current bandwidth allocation schemes could not satisfy with the demand of low delay and high assess rate for new satellite services. This paper focuses on bandwidth allocation method for satellite communication services compositions. The novel models of services compositions with single‐hop Poisson distribution are designed to simulate original traffic arrival. Isolated independent coefficients take an original distribution to adapt to isolated disconnections. Services queue waiting time would be judged by acceptable delay threshold. Models provide new services compositions with more precise arrival distributions. In order to improve traffic congestion, the method combined services models, and a network performance is proposed. Optimal reserved bandwidth is set according to the priority and arrival distribution of different services compositions, which classify services with feedback transmission performance. We design minimum fuzzy delay tolerant intervals to calculate delay tolerant threshold, which adapt random delay changes in the services network with delay tolerant features. The simulation in OPNET demonstrates that the proposed method has a better performance of queuing delay by 16.3%, end‐to‐end delay by 18.7%, and bandwidth utilization by 13.2%. Copyright © 2016 John Wiley & Sons, Ltd.     

面向全球能源互联网的天空地协同卫星通信网络架构

全球能源互联网的监测、调度、授时、同步及定位等业务均需要能提供广域覆盖、泛在灵活接入服务的可靠通信网络。针对该需求,首先分析阐述全球能源互联背景下各种新型业务需求及其特点,并总结各种业务的共性数据特征;然后论述卫星通信技术的特点以及与全球能源互联网业务特点与数据传输需求的高度契合性,最终提出融合卫星通信网络的全球能源互联网天空地协同网络体系架构。其以IP技术为基础,各层网络通过星间、星地、星空、空空、空地以及地面有线、无线链路连接起来,构建全球覆盖的一体化网络体系。     

IP路由协议在MF-TDMA卫星系统中适应性研究

MF-TDMA卫星通信系统可以实现卫星资源的有效利用和灵活组网,具有很大的潜在应用市场。同时,以IP技术为核心的宽带网络迅速发展,卫星通信作为一种广域网手段,实现对IP业务的接入,是其发展的必然趋势。主要研究了目前地面网络中常用的几种IP路由协议在MF-TDMA卫星通信系统中的适应性,利用OPNET网络仿真软件对MF-TDMA卫星通信系统进行仿真建模。通过对仿真结果的分析,给出了适合MF-TDMA卫星通信环境下的IP路由协议。     

基于SDN的战术通信网络架构研究

战术通信网络具有高动态、弱连接、低带宽和多链路备份等特性,软件定义网络（software defined network,SDN）技术通过传统网络控制设备软硬件解耦,将核心控制功能软件化,通过集中控制策略获取全局视图,从而实现资源的灵活调度与信道资源的高效利用,推动战术通信网络朝着更加智能化的弹性适变网络发展。首先介绍了SDN的发展现状及优势,分析了传统架构战术通信网络的若干问题,并对SDN技术在外军战术通信领域的应用情况进行了分析,提出了SDN在军事通信领域应用的可行性思路,对应用场景进行了构想,最后对SDN在军事通信领域的应用可行性进行了总结。     

基于能量效率的分布式星群下行链路功率分配方法研究

针对多波束卫星通信系统星上资源稀缺和能量利用效率不高的问题,本文提出了分布式星群网络下行链路中兼顾系统功耗和数据速率的功率分配方法,通过合理的资源分配来优化系统的能量效率.首先建立分布式星群功率分配模型,将复杂的分式问题转化为易于求解的减法形式问题,然后基于凸优化理论,提出功耗-数据速率权衡功率分配算法,并讨论了能量效率（energy efficiency）与频谱效率（spectral efficiency）之间的权衡关系.仿真结果验证了提出算法的有效性和EE-SE权衡关系,并分析了电路功耗对系统性能的影响.     

基于SDN的量子密码通信网络设计与研究

软件定义网络(SDN)采用OpenFlow技术分离网络设备的数据平面和控制平面,实现灵活控制网络资源的目的。基于此,设计了量子密码通信网络模型,实现灵活控制密码通信网络整体量子密匙资源,确保了信息的安全传输。此外,提出了综合到端可用密匙和跳数的路由算法,提高了QKD生成密匙的有效利用率。由测试结果可知,通过基于SDN的量子密码通信网络及路由算法,可提高量子密匙资源利用率,提高网络性能。     

卫星网络路由技术现状及展望

与地面固定通信网络不同,卫星网络的节点高度动态性、有限的星上处理能力和网络拓扑周期性变化的特点给卫星互联网的路由协议与算法设计带来了新的挑战。该文系统梳理了学术界针对卫星网络所提出的路由技术,提出了卫星路由技术未来的发展方向。首先介绍了卫星网络架构和目前在卫星通信系统上应用的主要路由协议,并且简要介绍了卫星光通信网络的路由问题;其次,根据卫星节点的管理方式以及路由表生成方式将路由算法分类为集中式卫星路由、分布式卫星路由以及混合式卫星路由,详细介绍了各类卫星路由方法的代表性成果并总结其优化目标和适用场景;接着,总结了不同卫星网络场景和网络需求下如何选择合适的卫星路由算法;最后,阐述目前卫星路由技术面临的挑战以及未来的发展趋势,并在附录中介绍了当前主流的卫星网络仿真平台。     

基于TDMA卫星通信系统的TCP增强技术研究

时分多址(TDMA)卫星通信系统具有组网灵活、能够有效地利用卫星资源、支持各类综合业务的接入等优点,目前已经成为国内外卫星发展和研究的热点。针对TDMA卫星通信系统的特点,提出了一种适用于TDMA卫星信道带宽动态变化条件下的传输控制层协议(TCP)加速机制。利用OPNET网络仿真工具对TDMA卫星通信系统进行了仿真建模,仿真结果表明,该TCP加速机制能有效提高IP数据的传输效率。     

多波束卫星通信功率带宽联合优化算法

在多波束卫星通信系统中,资源利用率受星上能量的限制,提高资源利用率非常重要。为提高星上资源优化的灵活性,在考虑自由空间损耗、天线增益、雨衰和波束间干扰的基础上,提出一种基于不同业务需求和信道条件的多波束卫星通信下行链路功率带宽联合优化算法。该联合优化算法采用二阶差分目标函数,运用拉格朗日对偶理论和次梯度法求得该联合优化问题最优解的下界。仿真结果分析表明,与单独地优化功率和带宽算法相比,该功率带宽联合优化算法可以根据不同的业务需求和信道条件更加灵活地分配系统容量,提高了资源利用率。      

基于迁移深度强化学习的低轨卫星跳波束资源分配方案

针对低轨(LEO)卫星场景下,传统资源分配方案容易造成特定小区资源分配无法满足需求的问题,该文提出一种基于迁移深度强化学习(TDRL)的低轨卫星跳波束资源分配方案。首先,该方案联合星上缓冲信息、业务到达情况和信道状态,以最小化卫星上数据包平均时延为目标,建立支持跳波束技术的低轨卫星资源分配优化模型。其次,针对低轨卫星网络的动态多变性,该文考虑动态随机变化的通信资源和通信需求,采用深度Q网络(DQN)算法利用神经网络作为非线性近似函数。进一步,为实现并加速深度强化学习(DRL)算法在其他目标任务中的收敛过程,该文引入迁移学习(TL)概念,利用源卫星学习的调度任务快速寻找目标卫星的波束调度和功率分配策略。仿真结果表明,该文所提出的算法能够优化卫星服务过程中的时隙分配,减少数据包的平均传输时延,并有效提高系统的吞吐量和资源利用效率。     

广电行业超融合架构云平台技术的应用

超融合架构是一种全新的计算架构,其主要特点是通过软硬件分离、应用与资源分离、软件与硬件分离、存储与计算分离、网络与计算分离等方式,统一管理和分配计算、存储、网络等资源,以软件定义的方式,提供按需扩展和按需付费的灵活计算资源和服务,并从架构上避免了传统架构存在的单点故障和数据泄露风险,降低了IT基础设施建设和运维成本,提升了资源利用率和业务系统的可用性。超融合架构技术是下一代互联网发展趋势。     

Class Dependent Traffic Allocation in a LEO Satellite Network

Traffic allocation strategy becomes a significant factor in optimization of bandwidth usage of telecommunication resources, especially with increasing use of broadband applications. Allocation strategy in dynamic LEO (Low Earth Orbital) satellite communication network is studied, to improve their Quality of Service (QoS). Traffic allocation control is performed to provide a near optimal utilization of their Inter Satellite Links (ISLs). A combination of two algorithms is used to allocate traffic in ISLs. Empirical analysis is performed to examine performance of the proposed algorithm, GALPEDA. Result shows that the proposed algorithm is useful for traffic allocation of multiclass traffic in LEO satellite communication.     

Interference‐Limited Dynamic Resource Management for an Integrated Satellite/Terrestrial System

An integrated multi‐beam satellite and multi‐cell terrestrial system is an attractive means for highly efficient communication due to the fact that the two components (satellite and terrestrial) make the most of each other's resources. In this paper, a terrestrial component reuses a satellite's resources under the control of the satellite's network management system. This allows the resource allocation for the satellite and terrestrial components to be coordinated to optimize spectral efficiency and increase overall system capacity. In such a system, the satellite resources reused in the terrestrial component may bring about severe interference, which is one of the main factors affecting system capacity. Under this consideration, the objective of this paper is to achieve an optimized resource allocation in both components in such a way as to minimize any resulting inter‐component interference. The objective of the proposed scheme is to mitigate this inter‐component interference by optimizing the total transmission power — the result of which can lead to an increase in capacity. The simulation results in this paper illustrate that the proposed scheme affords a more energy‐efficient system to be implemented, compared to a conventional power management scheme, by allocating the bandwidth uniformly regardless of the amount of interference or traffic demand.