Multi-objective routing algorithms for low-earth orbit satellite network

The low-earth orbit (LEO) satellite network, composed of a large number of satellite nodes, is a hot research topic at present. Due to the characteristics of the large-scale LEO satellite network, such as many satellite nodes, short orbit period, large dynamic change of topology, and unstable link-state, its communication quality of service (QoS) requirements are difficult to meet. Aiming at this problem, various factors that may affect data transmission are first analyzed. The network link selection problem is modeled as a multi-constraint optimization decision problem, a routing mathematical model based on linear programming (LP) is designed, and its solution is solved. Aiming at the problem of limited onboard computing resources, a multi-object optimization Dijkstra algorithm (MOODA) is designed. The MOODA finds the optimal path according to the comprehensive performance of the link. It solves the problems of poor comprehensive QoS performance and the low degree of load balancing of the paths found by the Dijkstra algorithm. The simulation results show that the paths found by the two algorithms have good QoS, robustness, and load balancing performance.     

QoS routing based on mobile agent for LEO satellite IP networks

Current quality of service (QoS) routing schemes for low earth orbit (LEO) satellites IP networks either neglect the varying population density or fail to guarantee end-to-end delay. As a remedy, QoS routing protocol based on mobile agent (QoSRP-MA) is proposed. QoSRP-MA is a source-based routing protocol. Once connection requests arrive, QoS mobile agents are dispatched from ingress satellite to explore routes, which migrate using satellite routing tables. Upon arriving in egress satellite, QoS mobile agents migrate back towards ingress satellite to reserve bandwidth. To construct satellite routing tables, load balancing routing algorithm based on mobile agent (LBRA-MA) is presented. In LBRP-MA, at regular intervals mobile agents launched on all satellites migrate autonomously to evaluate path cost and update routing tables. Moreover, path cost between source and destination is evaluated considering satellite geographical position as well as inter-satellite link (ISL) cost. Furthermore, ISL congestion index is considered to update routing table. Through simulations on a Courier-like constellation, it shows that QoSRP-MA can achieve guaranteed end-to-end delay bound with higher throughput, lower connection failing ratio and signaling overhead compared to high performance satellite routing (HPSR) scheme.     

Joint multi-QoS and energy saving routing for LEO satellite network

Low earth orbit(LEO) satellite network provides global coverage and supports a wide range of services. However, due to the rapid changes and energy-limitation of satellites, how to meet the demand of the quality of service(QoS) from ground traffic and prolong the lifetime of LEO satellite network is the research emphasis of the investigator. Hence, a routing algorithm which takes into account the multi-QoS requirements and satellite energy consumption(QER) of LEO satellite network is proposed. Firstly, the satellite intimacy degree(SID) and the path health degree(PHD) are introduced to obtain the path evaluation function according to the energy consumption and queue state of the satellite. Then, the distributed routing QER is established through the path evaluation function and the idea of genetic algorithm(GA), which enables each satellite to adjust traffic and realizes the network load balancing. Simulation results show that QER performs well in terms of end-to-end delay, delay jitter, and system throughput.     

低轨卫星星座快速响应链路损毁路由算法

设计高效弹性的卫星路由算法是未来低轨(Low Earth Orbit, LEO)卫星通信技术的一个重要发展方向。为解决低轨卫星星座网络中星间链路发生故障后存在的传输中断和数据安全问题,提出了一种低轨卫星星座快速响应链路损毁路由算法(Quick-response Link Destruction Routing Algorithm for LEO Satellite Constellation, QRLDRA)。QRLDRA以星座可预测拓扑作为星间路由计算基础,增加星地回传路由设计,快速将星间链路异常回传至地面计算中心处理;引入多优先级动态队列,根据节点链路状态调整星间链路不同数据传输的优先级;综合路由计算、路由上注、链路检测等功能,完成对拓扑变化的及时响应。通过仿真实验与传统算法的比较发现,所提算法有效提高了数据端到端传输的成功率,为用户业务服务质量(Quality of Service, QoS)提供了可靠保障。     

A sustainable heuristic QoS routing algorithm for pervasive multi-layered satellite wireless networks

Due to the recent developments in wireless technology and electronics, it is feasible to develop pervasive algorithms for satellite environments. Multi-Layered Satellite Networks (MLSNs) that consist of low earth orbit and medium earth orbit satellites are becoming increasingly important since they have higher coverage and better service than single-layered satellite networks. One of the challenges in MLSNs is the development of specialized and efficient routing algorithms. In this paper, we improved the virtual topology strategy and import heuristic algorithm to satisfy the QoS requirements of the MLSN users. The QoS requirements include end to end delay; link utilization, bandwidth, and package loss rate are mainly focused in this paper. To satisfy the QoS requirements is a multi-parameter optimization problem, and it is convinced as a Non-deterministic Polynomial Complete problem already. As a solution, three typical heuristic algorithms—Ant Colony Algorithm, Taboo Search Algorithm and Genetic Algorithm are applied in the routing scheme in order to reduce package loss, link congestion and call blocking. Simulation results show that heuristic routing algorithm can provide more QoS guarantees than shortest path first algorithm on package loss rate, link congestion and call blocking.     

软件定义卫星光网络蚁群优化波长路由技术

针对卫星光网络中网络拓扑动态时变和业务类型多样化的问题,研究了在软件定义网络架构下保障服务质量的路由技术,提出了一种基于多业务的卫星光网络蚁群优化波长路由算法。通过改进蚁群算法的启发函数,将波长空闲率、时延、时延抖动、丢包率作为蚂蚁选路的重要依据,为业务选择了满足多种服务质量的最优路径;采用分组波长分配方法对不同等级的业务进行了区分服务,为不同业务分配了不同的波长集。仿真结果表明:与CL-ACRWA算法和Dijkstra算法相比,降低了卫星光网络的平均时延、平均时延抖动、平均丢包率,提高了波长利用率,同时也降低了高优先级业务的网络拥塞概率。     

A distributed QoS routing based on ant algorithm for LEO satellite network

Low Earth Orbit (LEO) satellites provide short round-trip delays and are becoming in- creasingly important. One of the challenges in LEO satellite networks is the development of specialized and efficient routing algorithms. To satisfy the QoS requirements of multimedia applications, satellite routing protocols should consider handovers and minimize their effect on the active connections. A distributed QoS routing scheme based on heuristic ant algorithm is proposed for satisfying delay bound and avoiding link congestion. Simulation results show that the call blocking probabilities of this al- gorithm are less than that of Shortest Path First (SPF) with different delay bound.     

基于卫星时变网络的时延受限最小费用路由算法

卫星网络是一种特殊的时变网络,其QoS路由问题比地面网络QoS路由问题更为复杂.本文利用卫星拓扑的可预测性,通过引入业务的中断概率和费用模型来描述链路切换对业务QoS以及网络的影响,并给出时延受限最小费用路由(SDCMCR)算法来解决在卫星链路时延长的情况下寻找满足时延限制条件且受切换影响最小的路径的问题,该算法可兼顾网络业务中断率和业务阻塞率等性能,且计算复杂度低,可适应星上设备处理能力的要求.仿真表明算法在计算复杂性、业务请求被阻塞的概率等方面都优于同类算法.     

双层卫星网络QoS路由算法研究

具有星际链路的双层通信星座网络可为全球提供宽带实时多媒体通信服务,路由算法设计是其中关键技术之一。本文详细介绍了由低轨卫星与中轨卫星构成的空间信息通信网双层星座系统体系结构,提出了一种新的具有QoS保证的双层卫星网络路由算法。仿真结果表明提出的路由算法可以满足系统的QoS业务要求的延迟、丢包率与抖动等指标。     

A novel QoS routing protocol for LEO and MEO satellite networks

The rapid advance of communication and satellite technology pushes broadband satellite networks to carry on multimedia traffic. However, the function of onboard routing cannot be provided in existing satellite networks with inter‐satellite links, and quality of service (QoS) of satellite networks cannot be reliably guaranteed because of great difficulties in processing of long distance‐dependent traffic. In this paper, a two‐layered low‐Earth orbit and medium‐Earth orbit satellite network (LMSN) is presented. A novel hierarchical and distributed QoS routing protocol (HDRP) is investigated, and an adaptive bandwidth‐constrained minimum‐delay path algorithm is developed to calculate routing tables efficiently using the QoS metric information composed of delays and bandwidth. The performance of LMSN and HDRP is also evaluated through simulations and theoretical analysis. Copyright © 2007 John Wiley & Sons, Ltd.     

低轨卫星星座网的切换研究

提出了一种适用于装备有星际链路的低轨卫星星座网的切换策略——最小跳数切换策略。该策略以端到端连接的跳数为基础,充分利用了低轨星座网的特点,将切换过程与路由有机地结合为一体,有效解决了不同卫星之间的切换问题。仿真结果表明,同已有的切换策略相比,该策略能够提供一定程度的QoS保障,获得较好的系统性能,如较低的传播延时和较小的切换频率,具有很好的实用价值。     

一种基于QoS的选播路由算法研究

随着计算机和网络技术的迅猛发展,对网络服务质量的要求越来越高,因此选播成为了IPv6中的一种标准通信模型。在提出了一种新的解决多种限制条件下QoS路由问题的启发式算法,在该算法中,综合考虑了时延、带宽和费用的限制条件,主要采用了网络链路信息预先处理和改进的宽度优先搜索等方法。实验结果表明,该算法具有良好的性能指标,能够有效解决多种限制条件下的QoS路由问题,并且较好的平衡网络负载和服务器负载。     

一种基于分时的LEO卫星网络无环路由算法

在分析传统卫星网络路由算法的基础上，提出一种基于分时的LEO卫星网络无环路由算法(DTRA)。针对卫星在各时间片之间进行路由表切换时可能出现的路由环问题，算法采用平滑路由表切换策略消除由于切换前后网络状态信息不一致而产生环路的可能性，保证分组在任何时刻都能够沿无环最短时延路径被转发。同时，DTRA也能够通过使用无环备份路径处理可能出现的链路拥塞、节点失败等突发情况。通过复杂性分析可知，算法只需较小的星上存储开销和星上处理开销，而无需星问通信开销。仿真实验结果也表明算法能够提供数据最优传送，具有较好的端到端时延性能。     

一种高效的分布式QoS路由算法的研究

该文提出了一种以带宽为度量标准,改进的分布式QoS路由算法,它不仅继承了分布式QoS路由算法简单、链路开销小的优点,而且可以减少网络处于重负荷时所产生的资源碎片,接纳更多的业务。同时,通过确定本算法的启动门限,可以在保证算法性能的同时,大大降低引入的路径建立时延。计算机仿真结果证明了这种算法的正确性和高效性。     

QoS单播路由算法的研究

本文在综合烽务QoS和网络性能参数的基础上,提出了一个新的路由度量标准BHD,然后提出了一种优化的QoS单播路由算法BHDR,仿真研究表该算法在满足业务连接时延要求的同时提高了网络的吞吐量,较好的改善了网络的性能。     

Research on hierarchical architecture and routing of satellite constellation with IGSO‐GEO‐MEO network

In this paper, a three‐layered medium Earth orbit (MEO), geostationary Earth orbit (GEO), and inclined geosynchronous orbit (IGSO) satellite network (IGMSN) is presented. Based on the idea of time‐slot division, a novel dynamic hierarchical and distributed QoS (quality of service) routing protocol (HDRP) is investigated, and an adaptive bandwidth‐constrained minimum‐delay path for IGSO/GEO/MEO hierarchical architecture constellation (BMDP‐HAC) algorithm is developed to calculate routing tables efficiently using the QoS metric information composed of delays and bandwidth. The performance of the IGMSN and HDRP is evaluated through simulations and theoretical analysis. And then, the paper further analyzes the performance of the IGMSN structure and the BMDP‐HAC algorithm with failure satellites.     

Load balancing routing with bandwidth-delay guarantees

The current generation of network carriers competes intensely to satisfy the diverse wide-area connectivity requirements of customers. At the same time, the carriers inherently wish to maximize the usage efficiency of their network infrastructure. Much of the research in network resource management has been devoted to providing bandwidth guarantees and preventing network congestion. However, the rapid growth in number and diversity of real-time network applications has made it imperative to consider the impact of end-to-end delay of traffic requirements on network resource provisioning. We present an efficient network resource provisioning algorithm, called link criticality based routing (LCBR), which relies on the guiding theme that load balancing leads to higher resource utilization efficiency. LCBR applies a simple but very effective notion of link criticality to achieve networkwide load balance while simultaneously meeting the QoS requirements of bandwidth and end-to-end delay. In addition, LCBR can simultaneously provision both primary and backup routes to support fast recovery from node or link failures. This article reviews the state of the art in network resource provisioning with QoS guarantees, introduces the LCBR algorithm, and identifies future research challenges.     

一种应急通信中业务感知的宽带自组网路由协议

随着科技进步,我国在应急通信系统建设上也正高速发展,当前应急通信网络对多媒体业务有着迫切需求,对网络带宽要求更高。而当网络存在多种不同业务时,传统通用的路由协议不再适用,它们大多以最小跳数为路由度量或者是某个单一度量,未能考虑不同业务的服务质量(Quality of Service, QoS)需求,因而无法同时兼顾不同业务流的传输要求。提出了一种应急通信中业务感知的宽带自组网路由策略,对不同类型业务在路由和转发优先级上进行区分。经多次仿真验证,该策略能使网络在满足应急语音业务QoS需求的同时,也能兼顾承载的视频、数据等其他业务的性能。     

A demand-assignment algorithm based on a Markov modulated chain prediction model for satellite bandwidth allocation

This article deals with the problem of the design of a control-based demand-assignment algorithm for a satellite access network using a Markov modulated chain traffic prediction model. The objective is to guarantee a target Quality of Service (QoS) to Internet traffic, while efficiently exploiting the air interface. The proposed algorithm is in charge of dynamically partitioning the uplink bandwidth capacity in a satellite spotbeam among the in-progress connections. Such partition is performed aiming at matching the QoS requirements of each connection and maximizing the satellite bandwidth exploitation. A closed-loop Control Theory approach is adopted to efficiently tackle the problem of the delay between bandwidth requests and bandwidth assignments, while minimizing the signaling overhead caused by control messages. The algorithm efficiently copes with both the satellite propagation delay and the delays inherent in the periodic nature of the bandwidth request mechanism. The proposed demand-assignment algorithm and Markov chain traffic prediction model are shown to improve the overall satellite network performance through extensive simulation experiments.     

面向带宽碎片最小化和QoS保障的数据中心网络流量调度算法

随着数据中心网络流量的迅速增长,如何提高数据中心网络性能和服务质量成为了研究热点。然而现有的流量调度算法在网络负载加大时,一方面会导致网络带宽碎片化从而使得网络吞吐量降低,另一方面忽视了流量应用需求导致网络服务质量较差。为此,该文提出一种面向带宽碎片最小化和QoS保障的动态流量调度算法,算法综合考虑了带宽敏感的大流、时延与丢包敏感的小流的不同需求,首先根据待调度流的源地址和目的地址建立最短路径集,其次从中筛选出满足待调度流的带宽需求的所有路径,然后根据路径剩余带宽信息和小流应用需求情况为每条路径建立权重函数,最后根据权重函数值利用轮盘赌算法选择转发路径。实验仿真结果显示,与其它算法相比,所提算法降低了小流的丢包率和时延,同时在网络负载较大时提升了网络吞吐量。