Abstract — Mobile IP is the current standard for supporting macromobility of mobile hosts. However, in the case of micro-mobility support, there are several competing proposals. In this paper, we present the design, implementation, and performance evaluation of HAWAII: a domain-based approach for supporting mobility. HAWAII uses specialized path setup schemes which install host-based forwarding entries in specific routers to support intra-domain micro-mobility. These path setup schemes deliver excellent performance by reducing mobility related disruption to user applications. Also, mobile hosts retain their network address while moving within the domain, simplifying QoS support. Furthermore, reliability is achieved through maintaining soft-state forwarding entries for the mobile hosts and leveraging fault detection mechanisms built in existing intradomain routing protocols. HAWAII defaults to using Mobile IP for macromobility, thus providing a comprehensive solution for mobility support in wide-area wireless networks.

this paper, we propose a method to modify the CSMA/CA protocol such that station priorities can be supported. The method is simple, e#cient and easy to implement in comparison to point coordination function (PCF), another access method in IEEE 802.11 based on access points (base stations). Simulations are conducted to analyze the proposed scheme. The results show that DCF is able to carry the prioritized tra#c with the proposed scheme.

Addressed is how to support both real-time and non-real-time communication services in a wireless LAN with Dynamic Time Division Duplexed (D-TDD) transmission. With D-TDD, a frequency channel is time-shared for both downlink and uplink transmissions under the dynamic access control of the base station. The base station (i) handles uplink transmissions by polling mobiles in certain order determined on a per-connection (per-message) basis for transmitting real-time (non-real-time) traffic from mobiles; and (ii) schedules the transmission of downlink packets. To handle location-dependent, time-varying, and bursty errors, we adopt the channel-state prediction, transmission deferment, and retransmission. We consider the problems of scheduling and multiplexing downlink packet transmissions, and polling mobiles for uplink transmissions depending on the channel state. We also establish conditions necessary to admit each new real-time connection by checking if the connection's delivery-delay bound can be guaranteed as long as the channel stays in good condition without compromising any of the existing guarantees. Finally, the performance of the proposed protocol is evaluated to demonstrate how the protocol works, and study the effects of various parameters of the protocol.

This work provides the results of the on-going design and implementation of a control and management network (an orderwire) for a mobile wireless ATM system. There are novel uses for an orderwire which receives time and position from the Global Positioning System (GPS). Position information is used for such things as beam steering and determination of switch to host associations. The accurate time provided by the GPS is used by the network configuration system for a proposed rapid configuration algorithm.

This article deals with the problem of virtual circuit (VC) management in wireless ATM (W-ATM) networks with mobile user terminals. In W-ATM networks, a VC terminating at a mobile user may require dynamic reestablishment during the short time span necessary for terminal handover due to its movement from one (macro)cell to another. The VC reestablishment procedure has to ensure in-sequence and loss-free delivery of the ATM cells containing user data. After a classification of the solutions proposed so far in the literature, a novel technique for the dynamic reestablishment of VCs in W-ATM networks is described, and its performance is evaluated through simulation. The proposed technique allows for a progressive upgrade of the fixed part of the ATM network and for the incremental introduction of user terminal mobility.

IEEE 802.11, the standard of Wireless Local Area Networks (WLANs), allows the coexistence of asynchronous and time-bounded traffic using the Distributed Coordination Function (DCF) and Point Coordination Function (PCF) modes of operations, respectively. In spite of its increasing popularity in real-world applications, the protocol suffers from the lack of any priority and access control policy to cope with various types of multimedia traffic as well as user mobility (handoff).To expand support for applications with Quality-of-Service (QoS) requirements, the 802.11E Task Group was formed to enhance the original IEEE 802.11 Medium Access Control (MAC) protocol. However, the problem of choosing the right set of MAC parameters and QoS mechanism to provide predictable QoS in IEEE 802.11 networks is still remain unsolved. In this paper, we propose a polling with non-preemptive priority based access control scheme for the IEEE 802.11 protocol. Under such a scheme, modifying the DCF access method in the contention period supports multiple levels of priorities such that user mobility can be supported

This paper presents a QoS oriented Data Link Control (DLC) framework for transporting Constant Bit Rate (CBR) traffic over wireless ATM links. Data link control is usually omitted in fixed ATM networks because cell corruption due to channel error is extremely rare for reliable media like copper wire and optical fiber. However, for wireless, higher bit error rates are quite common due to shadowing and other fading effects. The purpose of DLC in wireless is to provide error-free transport to the higher layers by recovering corrupted cells at the link layer. A selective reject (SREJ) automatic repeat request (ARQ) based DLC protocol is used for CBR error recovery. For an ARQ based scheme, higher recovery rates can be achieved with larger cell transfer delay, caused by cell retransmissions. Since cell transfer delay and DLC recovery rate both translate to user-perceivable Quality-of-Service (QoS), it is important for the DLC to strike a balance between these two, depending on the application's requirements. To achieve this in our protocol, the retransmission procedure for a CBR cell is constrained to complete within a recovery time interval which is specified by the application at call-setup time. Also, a novel jitter removal scheme that reduces the cell delay variation caused by cell loss and retransmissions, is incorporated as a part of the DLC protocol. The proposed protocol is implemented on NEC's WATMnet prototype system. The implementation and its experimental results are reported for illustrating the performance and feasibility of the presented CBR DLC protocol. The experimental results show that the DLC protocol can be successfully applied for QoS-constrained error recovery of CBR traffic on a per-connection basis. These also indicate that the DLC can be programme...

This is a speci#cation for the network architecture and functionality of the Rapidly Deployable Radio Network. Invariants for each protocol layer, as well as con#guration, recon#guration, link quality, and mobility are speci#ed. Implementation of high level functionality is prioritized, while refraining from over-specifying some of the interesting areas of research. Existing standards and areas of research are identi#ed providing a framework for the development of the mobile wireless ATM Rapidly Deployable Radio Network architecture. 1 Introduction This is a speci#cation of the network architecture, components, and functionality for the Rapid Deployment Radio Network. This speci#cation attempts to be independent of implementation details such as where and how functionality is implemented. Functionality is rated as mandatory, high priority, or optional. Mandatory functions will be implemented, high priority functions maybeimplemented if time permits, and optional functions hav...

This research concentrates on the design and analysis of an algorithm referred to as Virtual Network Configuration which uses predicted future states of a system for faster network configuration and management. Virtual Network Configuration is applied to the configuration of a wireless mobile Asynchronous Transfer Mode network. Virtual Network Configuration is built on techniques from parallel discrete event simulation merged with constraints from real-time systems and applied to mobile ATM configura-tion and handoff. Configuration in a mobile network is a dynamic and continuous process. Factors such as load, distance, capacity and topology are all constantly changing in a mobile environment. The Virtual Network Configuration algorithm anticipates configuration changes and speeds the reconfiguration process by pre-computing and caching results. Virtual Network Configuration propagates local prediction results throughout the Vir-tual Network Configuration enhanced system. The Global Positioning System is an enabling technology for the use of Virtual Network Configuration in mobile networks

this paper, we describe our experiences in implementing extensions to the ATM Forum UNI/NNI signaling protocols to support terminal mobility. We also present empirical results quantifying the performance of these protocols. We have introduced four new signaling messages in UNI/NNI to ensure suc-