472 research outputs found
Performance Comparison of Handover Rerouting Schemes in Wireless ATM Networks
The major issue of the integration of wireless and wired ATM is the
support of user mobility. In effect, many technical challenges have been posed due
to mobility support. One of the most important challenges is the rerouting of active
connections of mobile user during handover. The rerouting of connections must
exhibit low handover latency, limit the handover delay or disruption time, maintain
efficient routes and minimise the impact on existing infrastructure.
To date, two dominant approaches have been proposed to support mobility
into fixed ATM network. The first is the mobility enhanced switches approach and
the second is the separate network-elements specific to mobility approach. The
first approach implies updating the existing ATM switches with mobile specific
features. The mobility functions in the second approach are entrusted to a control
station attached to the ATM switch as is implemented by the Magic WAND
projects. In this thesis, we investigate how mobility can be supported using both
approaches. To demonstrate the effectiveness of the above approaches, we
compare the performance by analytically derived formulate for their hand over
latency, hand over delay, buffer size, and bandwidth requirements. The formulate
were derived for both backward and forward hand overs using a number of
potential rerouting schemes proposed for wireless ATM network.
The results show that the mobility enhanced switches approach has slightly
better performance than the separate network elements approach. The results also
show that backward handover has better performance than forward handover in
terms of the handover delay and buffer requirement. Finally, the results show that
the Anchor Switch rerouting scheme is the best among other rerouting schemes
proposed for wireless ATM
Flat Cellular (UMTS) Networks
Traditionally, cellular systems have been built in a hierarchical manner: many specialized cellular access network elements that collectively form a hierarchical cellular system. When 2G and later 3G systems were designed there was a good reason to make system hierarchical: from a cost-perspective it was better to concentrate traffic and to share the cost of processing equipment over a large set of users while keeping the base stations relatively cheap. However, we believe the economic reasons for designing cellular systems in a hierarchical manner have disappeared: in fact, hierarchical architectures hinder future efficient deployments. In this paper, we argue for completely flat cellular wireless systems, which need just one type of specialized network element to provide radio access network (RAN) functionality, supplemented by standard IP-based network elements to form a cellular network. While the reason for building a cellular system in a hierarchical fashion has disappeared, there are other good reasons to make the system architecture flat: (1) as wireless transmission techniques evolve into hybrid ARQ systems, there is less need for a hierarchical cellular system to support spatial diversity; (2) we foresee that future cellular networks are part of the Internet, while hierarchical systems typically use interfaces between network elements that are specific to cellular standards or proprietary. At best such systems use IP as a transport medium, not as a core component; (3) a flat cellular system can be self scaling while a hierarchical system has inherent scaling issues; (4) moving all access technologies to the edge of the network enables ease of converging access technologies into a common packet core; and (5) using an IP common core makes the cellular network part of the Internet
Mobile IP: state of the art report
Due to roaming, a mobile device may change its network attachment each time it moves to a new link. This might cause a disruption for the Internet data packets that have to reach the mobile node. Mobile IP is a protocol, developed by the Mobile IP Internet Engineering Task Force (IETF) working group, that is able to inform the network about this change in network attachment such that the Internet data packets will be delivered in a seamless way to the new point of attachment. This document presents current developments and research activities in the Mobile IP area
Motorized cart
Motorized cart is known as an effective tool and timeless that help people carry heavy loads. For farmers, it has an especially vital tool for moving goods. Oil palm farmers typically uses the wheelbarrow to move the oil palm fruit (Figure 10.1). However, there is a lack of equipment that should be further enhanced in capabilities. Motorized carts that seek to add automation to wheelbarrow as it is to help people save manpower while using it. At present, oil palm plantation industry is among the largest in Malaysia. However, in an effort to increase the prestige of the industry to a higher level there are challenges to be faced. Shortage of workers willing to work the farm for harvesting oil palm has given pain to manage oil palm plantations. Many have complained about the difficulty of hiring foreign workers and a high cost. Although there are tools that can be used to collect or transfer the proceeds of oil palm fruits such as carts available. However, these tools still have the disadvantage that requires high manpower to operate. Moreover, it is not suitable for all land surfaces and limited cargo space. Workload and manpower dependence has an impact on farmers' income
Design Aspects of a Testbed for an IPv6-Based Future Network for Aeronautical Safety and Non-Safety Communication
Mineralogy & gem
Quality of Service Management and Interoperability
Information technology: general issue
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
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