Integrated services packet networks with mobile hosts: Architecture and performance

This paper considers the support of real-time services to mobile users in an Integrated Services Packet Network. In the currently existing architectures, the service guarantees provided to the mobile hosts are mobility dependent, i.e., mobile hosts experience wide variation in the quality of service and often service disruption when hosts move from one location to another. The network performance degrades significantly when mobile hosts are provided with mobility independent service guarantees. In this paper we have proposed a service model for mobile hosts that can support adaptive applications which can withstand service degradation and disruption, as well as applications which require mobility independent service guarantees. We describe an admission control scheme for implementing this service model and evaluate its performance by simulation experiments. Simulation results show that, if sufficient degree of multiplexing of the mobility dependent and independent services are allowed, the network does not suffer any significant performance degradation and in particular our admission control scheme achieves high utilization of network resources.     

DiffServ resource allocation for fast handoff in wireless mobileInternet

The next-generation wireless networks are evolving toward a versatile IP-based network that can provide various real-time multimedia services to mobile users. Two major challenges in establishing such a wireless mobile Internet are support of fast handoff and provision of quality of service (QoS) over IP-based wireless access networks. In this article, a DiffServ resource allocation architecture is proposed for the evolving wireless mobile Internet. The registration-domain-based scheme supports fast handoff by significantly reducing mobility management signaling. The registration domain is integrated with the DiffServ mechanism and provisions QoS guarantee for each service class by domain-based admission control. Furthermore, an adaptive assured service is presented for the stream class of traffic, where resource allocation is adjusted according to the network condition in order to minimize handoff call dropping and new call blocking probabilities     

A new signaling protocol for intersystem roaming in next-generationwireless systems

In next-generation wireless systems, one of the major features that is different from the current personal communication service systems is the seamless global roaming. The mobile subscribers will be allowed to move freely across different networks while maintaining their quality of service for a variety of applications. To meet this demand, the signaling protocol of mobility management must be designed, supporting location registration and call delivery for roaming users who move beyond their home network. A new signaling protocol is proposed, emphasizing the active location registration for ongoing services during the mobile subscribers' movement. Another important goal of this new protocol is to reduce the overhead caused by mobility management so that the signaling traffic load and consumption of network resources can be reduced. The new protocol efficiently reduces the latency of call delivery and call loss rate due to crossing wireless systems with different standards or signaling protocols. The numerical results reveal that the proposed protocol is effective in improving the overall system performance     

Aggregate History of User Mobility Pattern for QoS Provisioning in Multimedia Wireless Networks

Multimedia traffic is expected to be included in the next generation of wireless networks. As in wireline networks, the wireless network must also be capable of providing guaranteed quality-of-service (QoS) over the lifetime of mobile connections. In this paper, a bandwidth reservation scheme incorporating a user mobility prediction is proposed to manage the QoS of the networks. The mobility prediction scheme is developed based on the aggregate history of mobile users. Based on the mobility prediction, bandwidth is reserved to guarantee the uninterrupted handoff process. Simulation results demonstrate that the proposed scheme can guarantee the required QoS requirements in terms of handoff call dropping probability and new call blocking probability while maintaining efficient bandwidth utilization.     

Resource management for QoS support in cellular/WLAN interworking

To provide mobile users with seamless Internet access anywhere and anytime/ there is a strong demand for interworking mechanisms between cellular networks and wireless local area networks in the next-generation all-IP wireless networks. In this article we focus on resource management and call admission control for QoS support in cellular/WLAN interworking. In specific, a DiffServ interworking architecture with loose coupling is presented. Resource allocation in the interworking environment is investigated/ taking into account the network characteristics, vertical handoff, user mobility, and service types. An effective call admission control strategy with service differentiation is proposed for QoS provisioning and efficient resource utilization. Numerical results demonstrate the effectiveness of the proposed call admission control scheme.     

On Integrated Location and Service Management for Minimizing Network Cost in Personal Communication Systems

We investigate the notion of per-user integrated location and service management in personal communication service (PCS) networks by which a per-user service proxy is created to serve as a gateway between the mobile user and all client-server applications engaged by the mobile user. The service proxy is always colocated with the mobile user's location database such that whenever the MU's location database moves during a location handoff, a service handoff also ensues to colocate the service proxy with the location database. This allows the proxy to know the location of the mobile user all the time to reduce the network communication cost for service delivery. We investigate four integrated location and service management schemes. Our results show that the centralized scheme performs the best when the mobile user's SMR (service to mobility ratio) is low and CMR (call to mobility ratio) is high, while the fully distributed scheme performs the best when both SMR and CMR are high. In all other conditions, the dynamic anchor scheme is the best except when the service context transfer cost is high, under which the static anchor scheme performs the best. Through analytical and simulation results, we demonstrate that different users with vastly different mobility and service patterns should adopt different integrated location and service management methods to optimize system performance. Further, the best integrated scheme always performs better than the best decoupled scheme that considers location and service managements separately and management schemes that do not use any service proxy.     

Dynamic Location Management for Mobile Computing

This paper presents a dynamic and individualized location update scheme that considers each user's mobility patterns. The mobility patterns are used to create individualized location areas for each user. The proposed scheme is flexible and can be used in network with arbitrary cell topologies. The scheme, along with other existing schemes is simulated using realistic users' mobility and call arrival patterns, and network topology. The simulated environment consists of 90 cells representing the geographical area of the San Francisco bay, and 66,550 mobile users representing the typical classes of users that are normally present in a real cellular network. Results show the proposed scheme gives lower overall signaling costs, resulting in savings on the limited radio bandwidth that may have otherwise been used for location updates and paging.     

A distributed database architecture for global roaming in next-generation mobile networks

The next-generation mobile network will support terminal mobility, personal mobility, and service provider portability, making global roaming seamless. A location-independent personal telecommunication number (PTN) scheme is conducive to implementing such a global mobile system. However, the nongeographic PTNs coupled with the anticipated large number of mobile users in future mobile networks may introduce very large centralized databases. This necessitates research into the design and performance of high-throughput database technologies used in mobile systems to ensure that future systems will be able to carry efficiently the anticipated loads. This paper proposes a scalable, robust, efficient location database architecture based on the location-independent PTNs. The proposed multitree database architecture consists of a number of database subsystems, each of which is a three-level tree structure and is connected to the others only through its root. By exploiting the localized nature of calling and mobility patterns, the proposed architecture effectively reduces the database loads as well as the signaling traffic incurred by the location registration and call delivery procedures. In addition, two memory-resident database indices, memory-resident direct file and T-tree, are proposed for the location databases to further improve their throughput. Analysis model and numerical results are presented to evaluate the efficiency of the proposed database architecture. Results have revealed that the proposed database architecture for location management can effectively support the anticipated high user density in the future mobile networks.     

Overflow control for cellular mobility database

In a cellular phone system, the service area is partitioned into several location areas (LAs). Every LA is associated with a mobility database called visitor location register (VLR). When a mobile user enters an LA, the user must register to the VLR before receiving any cellular service. If the VLR is full, the registration procedure fails and the system cannot deliver services to the user under the existing cellular technology. To resolve this problem, we propose a VLR overflow control scheme to accommodate the incoming mobile users during VLR overflow. Our scheme only requires minor modifications to the existing cellular mobility management protocols. Particularly, no modification is made to the mobile phones. An analytic model is proposed to investigate the performance of the overflow control scheme. When exercising the scheme, the call setup procedure for an “overflow” user is more expensive than that for a “normal” user. Under the range of input parameters considered in our study, we show that even if the VLR overflow situation is serious, the overhead for exercising the overflow control scheme is very low     

Dynamic hierarchical mobility management strategy for mobile IP networks

One of the major challenges for the wireless network design is the efficient mobility management, which can be addressed globally (macromobility) and locally (micromobility). Mobile Internet protocol (IP) is a commonly accepted standard to address global mobility of mobile hosts (MHs). It requires the MHs to register with the home agents (HAs) whenever their care-of addresses change. However, such registrations may cause excessive signaling traffic and long service delay. To solve this problem, the hierarchical mobile IP (HMIP) protocol was proposed to employ the hierarchy of foreign agents (FAs) and the gateway FAs (GFAs) to localize registration operations. However, the system performance is critically affected by the selection of GFAs and their reliability. In this paper, we introduce a novel dynamic hierarchical mobility management strategy for mobile IP networks, in which different hierarchies are dynamically set up for different users and the signaling burden is evenly distributed among the network. To justify the effectiveness of our proposed scheme, we develop an analytical model to evaluate the signaling cost. Our performance analysis shows that the proposed dynamic hierarchical mobility management strategy can significantly reduce the system signaling cost under various scenarios and the system robustness is greatly enhanced. Our analysis also shows that the new scheme can outperform the Internet Engineering Task Force mobile IP hierarchical registration scheme in terms of the overall signaling cost. The more important contribution is the novel analytical approach in evaluating the performance of mobile IP networks.     

Channel Allocation Scheme for Handoff Control in Wireless Ad Hoc Network with Group Mobility

Because a wireless ad hoc network does not have a fixed backbone network and the mobile base station moves randomly, the conventional channel allocation scheme cannot efficiently predict group mobility and is not feasible to support a burst handoff traffic due to group mobility. In this paper, we propose an channel allocation scheme to solve this problem. Our scheme efficiently support burst handoff using guard channel and hello message in wireless ad hoc network with group mobility. We developed an analytical Markov model for the proposed scheme and evaluate our scheme in terms of new call and handoff blocking probability and channel utilization via simulation study. Simulation results show that our scheme offers better performance than the conventional schemes.     

Toward Efficient Service-Level QoS Provisioning in Large-Scale 802.11-Based Networks

Along with recent advances in mobile networking and portable computing technologies, there is a trend in the telecommunications industry toward the development of efficient ubiquitous systems that can provide a set of bandwidth-intensive and real-time services to multiple users while supporting their full mobility. Large-scale deployment of 802.1 1-based technologies will play an integral part in the construction of such ubiquitous wireless mobile systems. A challenging task in the development of such networks is efficient provisioning of QoS-enabled services for mobile users. In this context, we propose a scheme that constantly monitors the overall network performance to perform admission control and traffic conditioning at the 802.11-based access points and mobile terminals. The focus is on service-level fairness, where different flows from the same traffic class can still receive the same QoS level even if they have different bit rates. Furthermore, given the mobility of users, the success of any resource allocation and admission control model depends on the continuity of QoS guarantees across different WLANs. This article proposes a dynamic service level agreement negotiation protocol that allows mobile terminals to perform handoffs between different WLANs while maintaining the agreed level or service. End users also can change their service levels in response to changes in network conditions.     

Performance modeling for mobile telephone networks

In a mobile telephone network, users may move around the service area during conversations, which can significantly affect the efficiency of radio resource (i.e., radio channels) allocation in the network. The author describes a simple analytic model to study the effect of user mobility on the performance of a mobile telephone network. Throughout the derivation of the model, the intuition behind the equations is provided to explain how user behavior affects network performance. This model can be used to study different handoff schemes with single and mixed types of users with different mobility patterns     

泛在网络下的群组移动模型研究现状及展望

群组移动模型的研究对泛在网络下通信协议的设计、算法性能的评价等问题具有重要意义。泛在网络涉及多种终端同时为移动用户服务的场景,有效地整合终端能力需要有效的群组移动模型进行指导。总结了以往Ad Hoc网络下各种群组移动模型的特点和适用场景,结合泛在网络下多终端多网络的环境特点,以用户和业务为中心,对个人服务场景中的群组移动模型的构建方案进行了探讨和展望,提出了关键的技术要求。     

Novel velocity and call duration support for QoS provision in mobile wireless networks

This article presents a novel mobility-based resource reservation and call admission control scheme that is applicable to any real wireless multimedia network. The scheme exploits three key mobility parameters - the position, direction, and speed of a mobile unit - together with the duration of a particular call to accurately estimate the cell visiting probability in order to identify a shadow cluster of cells the unit is most likely to visit. Each cell in the cluster reserves resources for an estimated time interval, which is adapted depending on the aggregated probability of all active units visiting a particular cell. Simulation results confirm the superiority of the new scheme over the existing predictive mobility support scheme in terms of three QoS parameters: call blocking rate, call dropping rate, and channel utilization.     

Weighted Graph Based Clustering and Local Mobility Management for Dense Small Cell Network with X2 Interface

Along with the surge in mobile data, dense small cell network has become an effective method to improve system capacity and spectrum efficiency. However, because more small cells are deployed, the interference among dense small cells exacerbates. It also makes frequent handover for mobile users (UEs), which brings a great deal of signaling overhead to the core network. In order to solve the problems of interference and frequent handover, a novel clustering scheme for dense small cell network is proposed in this paper. The scheme is based on the weighted graph. First, we present a dense small cell clustering model based on X2 interface to minimize core network signaling overhead. To improve the usability of the model, we model the system as an undirected weighted graph. Then we propose the maximum benefit merging algorithm to reduce the complexity. This method enables adjacent small cells to cooperate and form virtual cellular cluster according to handover statistics information. Then we select cluster head (CH) according to certain rule in each cluster. Cluster head acts as the mobility anchor, managing the handovers between cluster members. This can reduce core network signaling overhead and the interference among small cells effectively. Compared with the 3GPP handover algorithm, the proposed clustering model in this paper can reduce the signaling overhead more than 70%. The simulation results show that the proposed clustering model can effectively cluster the dense small cell.     

Mobile flow-aware networks for mobility and QoS support in the IP-based wireless networks

As the volume of mobile traffic consisting of video, voice, and data is rapidly expanding, a challenge remains with the mobile transport network, which must deliver data traffic to mobile devices without degrading the service quality. Since every Internet service holds its own service quality requirements, the flow-aware traffic management in fine granularity has been widely investigated to guarantee Quality of Service (QoS) in the IP networks. However, the mobile flow-aware management has not been sufficiently developed yet because of the inherent constraints of flow routing in the mobile networks regarding flow-aware mobility and QoS support. In this paper, we propose a flow-aware mobility and QoS support scheme called mobile flow-aware network (MFAN) for IP-based wireless mobile networks. The proposed scheme consists of dynamic handoff mechanisms based on QoS requirements per flow to reduce the processing overhead of the flow router while ensuring QoS guarantee to mobile flows. The performance analyses of the proposed scheme demonstrate that MFAN successfully supports the mobile flow traffic delivery while satisfying the QoS requirement of flows in the wireless mobile IP networks.     

NonStop: continuous multimedia streaming in wireless ad hoc networks with node mobility

Guaranteeing continuous streaming of multimedia data from service providers to the users is a challenging task in wireless ad hoc networks, particularly when node mobility is considered. The topological dynamics introduced by node mobility are further exacerbated by the natural grouping behavior of mobile users, which leads to frequent network partitioning. Network partitioning poses significant challenges to the provisioning of continuous multimedia streaming services in wireless ad hoc networks, since the partitioning disconnects many mobile users from the centralized streaming service. In this paper, we propose NonStop, a collection of novel middleware-based run-time algorithms that ensures the continuous availability of such multimedia streaming services, while minimizing the overhead involved. The network-wide continuous streaming coverage is achieved by partition prediction and service replication on the streaming sources and assisted by distributed selection of streaming sources on regular mobile nodes and users. The proposed algorithms are validated by extensive results from performance evaluations.     

Smart Routers for Cross-Layer Integrated Mobility and Service Management in Mobile IPv6 Systems

We propose and analyze a cross-layer integrated mobility and service management scheme called DMAPwSR in Mobile IPv6 environments with the goal to minimize the overall mobility and service management cost for serving mobile users with diverse mobility and service characteristics. The basic idea of DMAPwSR is that each mobile node (MN) can utilize its cross-layer knowledge to choose smart routers to be its dynamic mobility anchor points (DMAPs) to balance the cost associated with mobility services versus packet delivery services. These smart routers are just access routers for MIPv6 systems except that they are capable of processing binding messages from the MN and storing the current location of the MN in the routing table for forwarding service packets destined to the MN. The MN’s DMAP changes dynamically as the MN roams across the MIPv6 network. Furthermore the DMAP service area also changes dynamically reflecting the MN’s mobility and service behaviors dynamically. Unlike previous mobility management protocols such as HMIPv6 that focus only on mobility management, DMAPwSR considers integrated mobility and service management. We develop an analytical model based on stochastic Petri nets to analyze DMAPwSR and compare its performance against MIPv6 and HMIPv6. We validate analytical solutions obtained through extensive simulation including sensitivity analysis of simulation results with respect to the network coverage model, the MN’s residence time distribution and the DMAP service area definition.