Mobile Backbone Networks

移动骨干网

• 批准号: 0087148
• 负责人: Izhak Rubin
• 金额: --
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0087148&HistoricalAwards=false
• 关键词: Mobile; Backbone; Networks

Providing reliable multimedia communications in mobile multihop wireless networks is a formidablechallenge. Communication networks in which all users are potentially mobile and untethered to any fixedwireline infrastructure arise in a variety of contexts. The mobile users of the system desire reliablecommunications, including real-time voice and video, notwithstanding the lack of a fixed infrastructure. Thatis, the disconnection probability should be low and certain quality of service (QoS) guarantees should beprovided: for many applications, the information exchanged should have low delay, low jitter and a low lossrate. In a fully distributed wireless network, there is no fixed (wired) backbone that can be exploited tocentralize some of the network management and routing functions. In order to provide the desired functionality, the mobile terminals must be organized into a network that has some hierarchical organization or reliable structure that is maintained (at least to some degree) under varying network connectivities. This structure should, if possible, be maintained in a distributed fashion, without reliance on a centralized controller. Our approach to solving the ad hoc network problem is to use an embedded hierarchical structure, withphysically different networks at the various levels. Recently, we have proposed the employment of a mobilebackbone to support guaranteed QoS (as well as best effort) applications for mobile networks. Certain mobileterminals are assigned to effectively serve as mobile base stations, and these selected users ("backbone nodes") together with their interconnecting communication links constitute the mobile backbone. The backbone network consists of a mesh topology with point-to-point links used to interconnect neighboring backbone nodes. The mobile backbone, which has a functionality analogous to a fixed backbone in a cellular network, is then exploited to make the routing, access control, scheduling and congestion control problems tractable. Such mobile backbone networks can also be exploited to supplement an employed ad hoc mobile network that lacks a transport backbone, and is thus not able to readily provide QoS guarantees to multimedia applications. This research proposes a new approach to synthesizing communication backbones for mobile wirelessnetworks. The backbone will satisfy user-specified accessibility and connectivity requirements and will support guaranteed QoS objectives. The mobile backbone construction algorithm will incorporate terminal positional information and a distance metric in order to discern geographical sections of the network with high concentrations of users. Pattern recognition based techniques will be developed and employed for the first time in the context of telecommunications networks in order to discern compact sections of the network, and to choose representative backbone nodes for these compact sections. This approach provides a new means of decomposing a global network into smaller simpler subnetworks, on each of which a backbone constructionalgorithm can then be run. Once the network has been divided into subnetworks (termed itclustersln), a backbone is then constructedfor each separate cluster. These separate intra-cluster backbones are then linked together to form a composite global backbone network with the desired functionality. New graph-theoretic algorithms will be developed to synthesize the separate intra-cluster backbones.These methodologies will incorporate deterministic and probabilistic relaxations of the backbones accessibility features. Investigations will also include preprocessing of the input graph that models the communications network and subgraph removal techniques to determine optimal topologies that can be exploited for backbone synthesis. Robust algorithms will be developed that ihlook aheadlp to possible future graph scenarios (based on terminal movement) and choose the best backbone for the ensemble. The global backbone construction algorithms will be simplified by decoupling the inter-cluster backboneconnectivity requirements from the intra-cluster connectivity requirements. A mobile backbone will bedesigned with a single user-specified inter-cluster connectivity requirement, but may have different user-specified intra-cluster connectivity requirements for each cluster. The inter-cluster backbone will beconstructed using graph-theoretic techniques wherein each cluster is treated as a single node a supernode.The mobile backbone construction algorithms will be analyzed and evaluated to optimize methods ofbackbone reconstitution under failures caused by nodal movement, environmental variations and loadingfluctuations. Extensive analyses and simulations will be performed to evaluate the performance of theproposed backbone construction protocol under several scenarios that correspond to, e.g., different mobilitypatterns, different network loads, and a multitude of multimedia applications. The mobile backbone networks to be investigated here are of significant importance in many applicationscenarios. They have been targeted for the implementation of next generation wireless networks for militaryunit operations, as well as for a multitude of commercial networks, which require rapid and reliable deployment in an area that lacks an existing fixed-backbone infrastructure. Included are civilian and government networks used for disaster relief purposes.

在移动多跳无线网络中提供可靠的多媒体通信是一项艰巨的挑战。在各种情况下，所有用户都可能移动并且不受任何固定线路基础设施的限制的通信网络出现了。尽管缺乏固定的基础设施，该系统的移动用户仍需要可靠的通信，包括实时语音和视频。也就是说，断开概率要低，并提供一定的服务质量（QoS）保证：对于许多应用来说，交换的信息应该具有低延迟、低抖动和低损失率。在一个完全分布式的无线网络中，没有固定的（有线的）骨干网可以用来集中一些网络管理和路由功能。为了提供所需的功能，必须将移动终端组织到具有某种分层组织或可靠结构的网络中，该网络在不同的网络连接下保持（至少在某种程度上）。如果可能的话，应该以分布式方式维护该结构，而不依赖于集中式控制器。我们解决自组织网络问题的方法是使用嵌入式分层结构，在不同的层次上使用物理上不同的网络。最近，我们建议使用移动骨干网来支持移动网络的有保证的QoS（以及最佳努力）应用程序。指定某些移动终端有效地充当移动基站，这些选定的用户（“骨干节点”）与它们相互连接的通信链路一起构成移动骨干。骨干网由网状拓扑结构组成，具有点对点链路，用于连接相邻的骨干节点。移动骨干网的功能类似于蜂窝网络中的固定骨干网，然后利用它使路由、访问控制、调度和拥塞控制问题易于处理。这种移动骨干网还可以用来补充所使用的缺乏传输骨干网的自组织移动网络，因此不能轻易地为多媒体应用程序提供QoS保证。本研究提出了一种新的移动无线网络通信骨干网合成方法。骨干网将满足用户指定的可访问性和连接性要求，并将支持有保证的QoS目标。移动主干网构建算法将结合终端位置信息和距离度量，以便识别用户高度集中的网络地理区域。基于模式识别的技术将首次在电信网络环境中得到开发和应用，以识别网络的紧凑部分，并为这些紧凑部分选择具有代表性的骨干节点。这种方法提供了一种将全局网络分解成更小、更简单的子网的新方法，然后可以在每个子网上运行骨干构造算法。一旦网络被划分为子网（称为集群），就会为每个单独的集群构建主干网络。然后将这些独立的集群内骨干网连接在一起，形成具有所需功能的复合全球骨干网。将开发新的图论算法来合成单独的集群内骨干网。这些方法将结合主干网可访问性特征的确定性松弛和概率松弛。研究还将包括模拟通信网络的输入图的预处理和子图去除技术，以确定可用于骨干合成的最佳拓扑。将开发健壮的算法，以预测未来可能的图形场景（基于终端移动），并为集成选择最佳骨干网。通过将集群间骨干网连接需求与集群内骨干网连接需求解耦，简化了全局骨干网构建算法。移动骨干网将被设计为具有单个用户指定的集群间连接要求，但对于每个集群可能具有不同的用户指定的集群内连接要求。集群间主干将使用图论技术构建，其中每个集群被视为单个节点或超级节点。对移动主干网构建算法进行分析和评估，以优化节点移动、环境变化和负载波动引起的故障下的主干网重构方法。将进行广泛的分析和模拟，以评估所提出的骨干网构建协议在几种场景下的性能，这些场景对应于不同的移动模式、不同的网络负载和多种多媒体应用。这里要研究的移动骨干网在许多应用场景中都具有重要意义。它们的目标是实现下一代无线网络，用于军事单位行动，以及大量商业网络，这些网络需要在缺乏现有固定骨干基础设施的地区快速可靠地部署。其中包括用于救灾目的的民用和政府网络。