232 research outputs found
A framework for fast handoff schemes in wireless ATM networks
Includes bibliographical references.In this research, we focus on providing a framework that extends the fixed ATM standard to support user mobility in future WATM networks. The WATM architecture allows for the migration of fixed ATM networks without major modifications. Thus most of the mobility functions are implemented on the wireless access network. The most important component supporting mobility in a cluster is the Mobility Enhanced Switch (MES). We propose using direct links between adjacent MESs to support Permanent Virtual Channels (PVCs) in order to facilitate fast inter-cluster handoffwith minimum handofflatency. This research addresses a framework on handoff mobility by proposing three fast handoff re-routing schemes based on the support of PVCs
Periodic Route Optimization for Handed-off Connections in Wireless ATM Networks
In Wireless ATM networks, user connections need to be rerouted during handoff as mobile users move among base stations. The rerouting of connections must be done quickly with minimal disruption to traffic. In addition, the resulting routes must be optimal. A reasonable approach is to implement handoff in two phases. In the first phase connections are rapidly rerouted and in the second phase a periodic route optimization procedure is executed. The route optimization should impose minimal signaling and processing load on the ATM switches. In this paper, we propose and study a periodic execution of route optimization for a two-phase handoff scheme. We study two types of execution: non-adaptive and adaptive. For the adaptive optimization, we consider two adaptation schemes that are dependent on network conditions. A simulation model is developed to study system performance. The adaptive route optimization is shown to minimize signaling and processing load while maximizing utilization of reserved resources
Efficient Micro-Mobility using Intra-domain Multicast-based Mechanisms (M&M)
One of the most important metrics in the design of IP mobility protocols is
the handover performance. The current Mobile IP (MIP) standard has been shown
to exhibit poor handover performance. Most other work attempts to modify MIP to
slightly improve its efficiency, while others propose complex techniques to
replace MIP. Rather than taking these approaches, we instead propose a new
architecture for providing efficient and smooth handover, while being able to
co-exist and inter-operate with other technologies. Specifically, we propose an
intra-domain multicast-based mobility architecture, where a visiting mobile is
assigned a multicast address to use while moving within a domain. Efficient
handover is achieved using standard multicast join/prune mechanisms. Two
approaches are proposed and contrasted. The first introduces the concept
proxy-based mobility, while the other uses algorithmic mapping to obtain the
multicast address of visiting mobiles. We show that the algorithmic mapping
approach has several advantages over the proxy approach, and provide mechanisms
to support it. Network simulation (using NS-2) is used to evaluate our scheme
and compare it to other routing-based micro-mobility schemes - CIP and HAWAII.
The proactive handover results show that both M&M and CIP shows low handoff
delay and packet reordering depth as compared to HAWAII. The reason for M&M's
comparable performance with CIP is that both use bi-cast in proactive handover.
The M&M, however, handles multiple border routers in a domain, where CIP fails.
We also provide a handover algorithm leveraging the proactive path setup
capability of M&M, which is expected to outperform CIP in case of reactive
handover.Comment: 12 pages, 11 figure
Periodic Route Optimization for Handed-off Connections in Wireless ATM Networks
In Wireless ATM networks, user connections need to be rerouted during handoff as mobile users move among base stations. The rerouting of connections must be done quickly with minimal disruption to traffic. In addition, the resulting routes must be optimal. A reasonable approach is to implement handoff in two phases. In the first phase connections are rapidly rerouted and in the second phase a periodic route optimization procedure is executed. The route optimization should impose minimal signaling and processing load on the ATM switches. In this paper, we propose and study a periodic execution of route optimization for a two-phase handoff scheme. We study two types of execution: non-adaptive and adaptive. For the adaptive optimization, we consider two adaptation schemes that are dependent on network conditions. A simulation model is developed to study system performance. The adaptive route optimization is shown to minimize signaling and processing load while maximizing utilization of reserved resources
Design and implementation of a functional WATM test bed to study the performance of handoff schemes
Includes bibliographical references.The focus of this research is on the design and implementation of a WATM functional architecture in order to facilitate a seamless handoff. The project includes an experimental implementation of the WATM network. This required the building of a prototype WATM network with existing ATM switches and implementing handover protocol schemes at both the access and network sides
Periodic Route Optimization for Handed-off Connections in Wireless ATM Networks
In Wireless ATM networks, user connections need to be rerouted during handoff as mobile users move among base stations. The rerouting of connections must be done quickly with minimal disruption to traffic. In addition, the resulting routes must be optimal. A reasonable approach is to implement handoff in two phases. In the first phase connections are rapidly rerouted and in the second phase a periodic route optimization procedure is executed. The route optimization should impose minimal signaling and processing load on the ATM switches. In this paper, we propose and study a periodic execution of route optimization for a two-phase handoff scheme. We study two types of execution: non-adaptive and adaptive. For the adaptive optimization, we consider two adaptation schemes that are dependent on network conditions. A simulation model is developed to study system performance. The adaptive route optimization is shown to minimize signaling and processing load while maximizing utilization of reserved resources
Performance Study of a Two-Phase Handoff Scheme for Wireless ATM Networks
This paper presents an analytical and simulation study of a two-phase handoff scheme for rerouting user connection in Wireless ATM networks. The two-phase handoff scheme provides a rapid rerouting of user connections in the first phase utilizing permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). In the second phase, a non-realtime route optimization procedure is executed to optimally reroute handed-off connection. In this paper, we study the performance of such a scheme as a function of various system load parameters. These parameters include originating call arrival rate, call holding time, and radio cell residual time. We examine the relation between the required bandwidth resources and optimization rate. Also we calculate and study the handoff blocking probability due to lack of bandwidth for resources reserved to facilitate the rapid rerouting
A Novel Handoff Scheme for Wireless ATM Networks
Mobility support and management in Wireless ATM networks poses a number of technical issues. An important issue is the ability to manage and reroute active connections during handoff as mobile users move among base stations. We propose a novel two-phase handoff scheme using permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). The virtual paths are used in the first phase to rapidly reroute user connections. In the second phase, a distributed optimization process is initiated to optimally reroute handed-off connections. In this paper, we address various control issues related to signaling and implementation of such a scheme including how to achieve optimal paths. We analytically calculate and study the handoff blocking probability and the bandwidth requirement for the reserved virtual paths. We also study the impact of processing and signaling load due to the second-phase route optimization. Both ATM CBR and VBR traffic types were considered for mobile user connections
A Novel Handoff Scheme for Wireless ATM Networks
Mobility support and management in Wireless ATM networks poses a number of technical issues. An important issue is the ability to manage and reroute active connections during handoff as mobile users move among base stations. We propose a novel two-phase handoff scheme using permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). The virtual paths are used in the first phase to rapidly reroute user connections. In the second phase, a distributed optimization process is initiated to optimally reroute handed-off connections. In this paper, we address various control issues related to signaling and implementation of such a scheme including how to achieve optimal paths. We analytically calculate and study the handoff blocking probability and the bandwidth requirement for the reserved virtual paths. We also study the impact of processing and signaling load due to the second-phase route optimization. Both ATM CBR and VBR traffic types were considered for mobile user connections
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