Wireless ATM Networks Research Articles

Performance analysis of cache strategy for signaling traffic management in a wireless ATM network

In a wireless ATM network for mobile multimedia services, conventional signaling protocols generate heavy traffic because the signaling load must be handled in a HLR (Home Location Register). This centralized structure of the wireless ATM network causes critical connection setup delays. Thus, distributed processing based on a reduction of the connection setup delays is needed in wireless ATM networks. A cache strategy for call delivery with cache updates of registration based on ATM multicasting is introduced with a comparison of the cost of cache scheme with the cost of a conventional scheme. Results show that the cache scheme has better performance than conventional methods when portable mobility is low with large traffic density.

Mobile multicasting in wireless ATM networks

Multicasting is a desired function in both wired and wireless networks. Currently, multicasting‐based applications have pervasive presence and influence in our Internet. Wireless ATM aims to support different traffic types over a high speed wireless network. In particular, traditional approaches towards multicasting in wired networks cannot be directly applied to mobile ATM networks. This includes the mechanism proposed to handle mobility in wired networks. In this paper, we address the issues behind multicasting in wireless ATM networks and the underlying mechanisms to support handoffs of both unicast and multicast connections. Through simulation, we evaluated the performance of optimal core‐based tree (CBT), late‐joined CBT, optimal source‐based tree (SBT), and late‐joined SBT during changing multicast host membership conditions. In addition, we evaluated the impact of multicast receivers' migration on the total link cost of the resultant multicast tree. Simulation results revealed that source‐based trees incur more total link costs under both dynamic host membership and receivers' migration scenarios. However, it generates less control messages than the distributed CBT and SBT approaches.

Dynamic location management scheme for location registers in wireless ATM networks

The authors propose an enhanced location management scheme for the location register (LR) scheme in wireless ATM networks. The main distribution is the use of at most two active LRs and the dynamic scope-limiting parameter S depending on the communication-to-computation cost ratio (CCR) as well as the call-to-move ratio (CMR). As a result, the proposed scheme can reduce the location management cost compared with the original LR scheme for the different CCR value and CMR value.

Performance Evaluation of the Identifier Splitting Algorithm with Polling in Wireless ATM Networks

This paper presents a performance analysis of the Identifier Splitting Algorithm combined with polling, a contention resolution scheme used to inform the Base Station about the bandwidth needs of the Mobile Station in a wireless ATM network. An analytical model leads to the evaluation of performance parameters which determine the throughput and the access delay of the algorithm for different system parameters. This analysis is used to investigate the influence of the system parameters on the performance, from which guidelines for parameter tuning can be derived.

Performance evaluation of path optimization schemes for inter-switch handoff in wireless ATM networks

One of the major design issues in wireless ATM is the support of inter‐switch handoff. An inter‐switch handoff occurs when a mobile terminal moves to a new base station connecting to a different switch. Recently, a two‐phase handoff protocol has been proposed to support inter‐switch handoff in wireless ATM networks. With the aim of shortening handoff delay while using the network resources efficiently, the two‐phase handoff protocol employs path extension for each inter‐switch handoff, followed by path optimization if necessary. To implement the two‐phase handoff protocol efficiently, we need to determine when to trigger path optimization. In this paper, we propose and analyze three path optimization schemes, namely: periodic, exponential, and Bernoulli, for the two‐phase handoff protocol. The design objective is to determine the time to invoke path optimization such that the average cost per connection is minimized. We develop a discrete time analytical model and a discrete‐event simulation model for comparing the performance of the three path optimization schemes. Results indicate that the Bernoulli path optimization scheme outperforms the other two schemes by providing a lower average cost per connection. The proposed models can also be adapted to analyze other path optimization schemes in general.

Scalable QoS-based IP multicast over label-switching wireless ATM networks

A Mobile IP multicast prototype that integrates a label-switching wireless asynchronous transfer mode, the mobile core-based multicast architecture, and an Internet multicast infrastructure is presented. MCOM creates multiple core-based layer 2 multicast trees that are independently established in member networks. They are interconnected via the Internet using layer 3 multicast routing. Gateways on the border of the Internet and wireless ATM networks convert ATM multicast traffic to suitable IP packets as well as converting from IP packets to ATM cells for MCOM. To solve the cell interleaving problem that results, ATM block transfer/immediate transmission capability is reasonably modified. Additionally, class-based block buffer management for ATM multicast connections is built into wireless ATM switches for soft quality of service control. Dynamic group management, multicast channel rerouting, and reliable multicasting are also studied in relation to existing Internet protocols like Mobile IP, Internet group management protocols, and multicast routing protocols.

A novel adaptive hybrid ARQ scheme for wireless ATM networks

This paper describes the design and performance of a novel adaptive hybrid ARQ scheme using concatenated FEC codes for error control over wireless ATM networks. The wireless links are characterized by higher, timedvarying error rates and burstier error patterns in comparison with the fiberdbased links for which ATM was designed. The purpose of the hybrid ARQ scheme is to provide a capability to dynamically support reliable ATMdbased transport over wireless channels by using a combination of our ARQ scheme lcalled SDLPr and the concatenated FEC scheme. The key ideas in the proposed hybrid ARQ scheme are to adapt the code rate to the channel conditions using incremental redundancy and to increase the starting code rate as much as possible with the concatenated FEC, maximizing the throughput efficiency. The numerical results show that our proposed scheme outperforms other ARQ schemes for all SNR values.

A study of deadlock models for a multiservice medium access protocol employing a slotted Aloha signalling channel

Medium access protocols for HFC and wireless ATM networks often use a collision based capacity request signalling channel which may rely on the slotted Aloha multiaccess principle. This paper studies the performance of a p-persistence slotted Aloha contention resolution algorithm (CRA), subject to extreme interstation correlation, by means of a discrete-time Markov chain analysis. We examine in detail the conditions leading to a deadlock-a situation where the time to collision resolution becomes unacceptably high and the system is practically unstable. We analyze two disaster scenario deadlock models, and study the effect of channel error probability, signalling traffic load, and the contention resolution algorithm used. We show that the key factor of the CRA is the collision rate and not channel errors. We propose and test three signalling channel capacity allocation schemes. We identify the best-performing of these three schemes as the cyclic contention mini-slot (CMS) sharing employing multiple CMSs per data slot. Finally, we demonstrate the need for implementation of an added scheme, which dynamically adjusts the p-persistence parameter.

Dynamic channel allocation in wireless ATM networks

During the last few years extensive research has been carried out to extend fixed ATM networks to mobile users. Currently the European Telecommunications Standards Institute (ETSI) is standardising new types of Broadband Radio Access Networks (BRAN): HIPERLAN/2 and HIPERACCESS. In cellular systems like HIPERLAN/2 the aspect of channel allocation plays an important role. In this paper two approaches for channel allocation are introduced and compared with each other concerning the spectrum efficiency and their influence on the implementation of wireless ATM networks and wireless LANs.

Virtual tree-based multicast routing with a distributed numbering algorithm for WM-ATM handover

The flexibility offered by the ATM transport mechanism and its potential capabilities, together with its compatibility with the B‐ISDN, makes ATM the prime candidate for the support of multimedia services over the wireless medium. However, technical issues remain to be resolved in relation to the feasibility of ATM for the support of mobility over the radio interface. This paper examines network issues in supporting handover in a wireless ATM network. In particular, analysis has been performed for a virtual tree-based network architecture. Results have shown that by using multicast transmission and by using a distributed numbering algorithm, the potential problems of cell-loss and cell-duplication have been eliminated.

A cell-numbering plan for seamless handoff in a wireless ATM network

This paper proposes a cell-numbering plan for mobile stations to handoff seamlessly to the cells in a wireless Asynchronous Transfer Mode (ATM) network. It also proposes a minimum-hop rerouting (MHR) method to perform the rerouting of user connections during the handoff. The cell-numbering plan assigns each cell an integer from 1 to 5, ensuring that neighboring cells will have different numbers. Any mobile station that performs a handoff beween any two cells can easily calculate if a reroute is needed. Furthermore, by using the MHR, the path between the originating and terminating mobile stations will be the shortest whenever either of them moves. The signaling bandwidth used for this kind of rerouting is believed to be the smallest among the methods reported to date.

WASS

Recent years have witnessed the rapid growth in demanding for the use of wireless networks especially the one with can transmit all the service. Wireless ATM is the one that fulfil those requirements. This paper looks at the security issues in wireless ATM networks. It proposes the security services into user and control plane.

A performance analysis scheme for intelligent wireless ATM networks

An intelligent network (IN) is a concept characterized by the distribution of network intelligence and capabilities wherever required within a telecommunications network. It is considered as a platform defining an environment that is rich in network capabilities and service functionality. IN technique can be applied to a variety of telecommunication networks including the public switched network, mobile network, and the integrated services digital networks. The introduction of intelligent services in ATM networks appears to be an attractive subject for researchers and service providers. In this paper, we analyse and evaluate the performance of wireless ATM network equipped with intelligent services. The mathematical analysis uses the concept of virtual resource, while the simulation evaluation is based on an object-oriented simulation approach using Java. Copyright © 1999 John Wiley & Sons, Ltd.

A performance analysis scheme for intelligent wireless ATM networks

A performance analysis scheme for intelligent wireless ATM networks

Modelling and evaluation of security induced delay in wireless ATM networks

No abstract available.

Mobility information for resource management in wireless ATM networks

User mobility poses a significant technical challenge to network resource management in wireless ATM (Asynchronous Transfer Mode) networks. In order to guarantee quality of service (QoS) to mobile users and to achieve a high efficiency in network resource management, the information of mobile users' handoff at a future moment is essential for statistical multiplexing. This paper develops a novel fuzzy logic inference system to estimate the user mobility information for a wireless ATM network which uses a direct sequence code division multiple access (DS/CDMA) protocol. The estimation is based on measured pilot signal strengths from a number of the nearest base stations by the mobile user. Numerical results are presented to demonstrate the performance of the proposed technique under various path losses and channel shadowing conditions. The proposed technique can achieve simplicity, accuracy and low cost.

Schemes for mobility management of wireless ATM networks

The growing fields of wireless networks and asynchronous transfer mode (ATM) are merging to form wireless ATM networks. This paper addresses dynamic bandwidth allocation, connection admission procedures, routing, and location management strategies in wireless ATM. More precisely, we investigate the issue of extending the private Network to Network Interface, PNNI, and protocols to support mobility. PNNI-based hierarchical routing, hand-off, location management and routing schemes are proposed to integrate wireless capabilities into ATM networks. These schemes provide fast and efficient hand-off connection processing mechanism and a reduction in the connection disruption time during a connection hand-off session. They also provide a predictable resource requirement of the mobile system during its connection. During a connection hand-off, misrouted cells can be re-routed to their destinations. This substantially reduces the overhead due to end-to-end re-transmissions invoked at higher layers. An analytical model is developed to illustrate the hand-off algorithm. Copyright © 1999 John Wiley & Sons, Ltd.

Explicit delay/jitter bounds for real-time traffic over wireless ATM

A high performance, frame-based, real-time ATM scheduler is proposed for the wireless multimedia environment. We introduce the Delayed Frame Queueing (DFQ) scheduling protocol which only defines the service priorities, deadlines and eligibility times of queued cells. The DFQ protocol does not define the particular fashion in which a mobile or base station gains access to the shared transmission medium; thus, we present DFQ as a generic protocol which can be combined with numerous types of MAC protocols. Key features of our strategy are its algorithmic and architectural simplicity, its non-ad hoc scheduling approach, and its unified treatment of all real-time streams at all service queues within a wireless ATM network. In addition, the delay and jitter bounds are uncoupled. In this way, end-to-end jitter can be tightly controlled even if medium access requires long indeterminate waiting durations.

A path optimization signalling protocol for inter-switch handoff in wireless ATM networks

In this paper, we study the connection rerouting problem due to inter-switch handoffs. The design objective is to guarantee the bandwidth and delay of a connection during its connection lifetime. We propose to use path extension for each inter-switch handoff, and invoke path optimization whenever one of the potential handoff paths exceed the delay constraint. During path extension, the selection of the extended path is modeled as a bandwidth-delay-constrained path problem. The path optimization signalling protocol ensures that ATM cell sequencing is maintained on the uplink and downlink by buffering cells at the anchor switch and the crossover switch, respectively.

Implementation of the wireless ATM access terminal

Multimedia applications with audio and video connections have created totally new bandwidth and Quality of Service (QoS) requirements for the computer data networks. In order to meet the new customer requirements also the wireless access networks have to be enhanced to support the increased demand for broadband services. Wireless ATM (WATM) technology has emerged as one of the most promising alternatives for implementing multimedia capable mobile networks. The Magic WAND (Wireless ATM Network Demonstrator) is an international research project designing a WATM network that provides indoor radio coverage and user mobility. The system is mainly targeted for customer premises networks and hot spots with a large number of people within a restricted area, such as airports. This paper describes the architecture of the wireless ATM terminal developed for the Magic WAND demonstrator. The focus is on the terminal software which supports the user mobility and the native ATM access on the Windows NT operating system environment. The first part of the paper presents the generic reference model for the broadband radio networks and describes the Magic WAND system architecture. The latter part of the document focuses on the terminal implementation presenting the structural breakdown of the terminal, the Windows NT operating system and the actual implementation. Finally, the paper depicts briefly the development process and applied design methods.