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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International journal of wireless information networks 3 (1996), S. 139-145 
    ISSN: 1572-8129
    Keywords: Handoff ; inter-RS, PACS ; direct connect anchor approach ; switch loopback anchor approach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract An early version of the Bellcorepersonal access communications systems (PACS) specified a method of providing inter-radio system (RS) handoff assuming an ISDN/AIN switching system. To support switching systems without ISDN/AIN capabilities, an alternative approach calledanchor RS handoff has been proposed for PACS. Two possible anchor RS approaches areswitch loopback anddirect connect. This paper studies the performance of the two anchor RS methods. We show that if users exhibit locality of movement, the switch loopback method is better. Otherwise, the direct connect method should be considered.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Wireless networks 1 (1995), S. 197-210 
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract We propose an auxiliary strategy, calledper-user forwarding, for locating users who move from place to place while using Personal Communications Services (PCS). The forwarding strategy augments the basic location strategy proposed in existing standards such as GSM and IS-41, with the objective of reducing network signalling and database loads in exchange for increased CPU processing and memory costs. The key observation behind forwarding is that if users change PCS registration areas frequently but receive calls relatively infrequently, it should be possible to avoid registrations at the Home Location Register (HLR) database, by simply setting up a forwarding pointer from the previous Visitor Location Register (VLR). Calls to a given user will first query the user's HLR to determine the first VLR which the user was registered at, and then follow a chain of forwarding pointers to the user's current VLR. We use a reference PCS architecture and the notion of a user'scall-to-mobility ratio (CMR) to quantify the costs and benefits of using forwarding and classes of users for whom it would be beneficial. We show that under a variety of assumptions forwarding is likely to yield significant net benefits in terms of reduced signalling network traffic and database loads for certain classes of users. For instance, under certain cost assumptions, for users withCMR〈0.5, forwarding can result in 20–60% savins over the basic strategy. This net benefit is due to the significant saving in location update compared to a penalty of moderately increased call setup times for the infrequent occasions when these users do receive calls.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International journal of wireless information networks 4 (1997), S. 163-171 
    ISSN: 1572-8129
    Keywords: HANDOFF ; BLOCKING PROBABILITY ; MOBILITY
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper presents a performance model for apersonal communications services (PCS) system whichgeneralizes results obtained by the authors, allowingfor a more realistic computation of basic PCS network parameters. In particular, this modelgeneralizes the call holding time and the cell residencetime distributions. On the basis of this model, wederive the handoff rates and the channel occupationtimes, and show how these can be applied to computethe call blocking probabilities in these networks. Asimplified numerical example is presented to demonstratethe application of the presented approach.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International journal of wireless information networks 4 (1997), S. 249-256 
    ISSN: 1572-8129
    Keywords: GSM ; SHORT MESSAGE SERVICE ; CELLULAR SYSTEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract GSM short message service provides aconnectionless transfer of messages with low-capacityand low-time performance. This article provides atutorial on GSM point-to-point short messaging. Theshort message protocol hierarchy is introduced and the mobileoriginated/terminated messaging procedures aredescribed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Mobile networks and applications 2 (1997), S. 303-304 
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Wireless networks 4 (1998), S. 419-426 
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract This paper studies the database failure recovery procedure for cellular phone networks as part of the Electronic Industries Association/Telecommunications Industry Association Interim Standard 41 (EIA/TIA IS-41). Before the location information of the database is recovered, phone calls may be lost. The restoration process can be sped up by having the mobile phones to periodically confirm their existence by radio contact with the cellular network. We show that, under some cost assumptions, periodic update interval should be chosen to be approximately equal to the call interarrival time, with more frequent updates for more unreliable system. We also show that the cost of an optimized system is relatively small and stable, if the system is even moderately reliable. Finally, if the system is at least moderately reliable, the effects of call origination rate and the rate at which Location Areas are crossed, are rather small, assuming that the periodic update interval was chosen as stated above. Thus, in such cases, optimization of the size of the Location Area can be made independent of the optimization of the periodic update process.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Wireless networks 5 (1999), S. 479-488 
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract This paper studies the effects of cell residence times on wireless private branch exchange (WPBX) systems. In a WPBX, several base stations are connected to a PBX, and the PBX is connected to the Public Switched Telephone Network. It is important to determine the external line capacity and the radio channel capacities of a WPBX to optimize its system performance. Our previous study utilized an analytic model to study WPBX without user mobility. This paper proposes both the analytic and the simulation models to investigate the performance for WPBX with user mobility. Specifically, we study the effects of handoff and the variance of the cell residence times on resource planning. Based on the workload to the WPBX, our study provides several guidelines to determine the capacities for the PBX and the base stations.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Mobile networks and applications 5 (2000), S. 191-198 
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In a Personal Communications Services (PCS) network, mobility databases such as Home Location Register (HLR) and Visitor Location Register (VLR) are utilized to support mobility management for Mobile Stations (MSs). If the location databases fail, the location information loss or corruption will seriously degrade the service offered to the subscribers. In this paper, we propose a new VLR failure recovery scheme called demand re‐registration. In this scheme, the VLR broadcasts a re‐registration request to all MSs after the VLR failure. When an MS receives the re‐registration request, it sends a registration message to the VLR to recover the location record. Since all MSs will re‐register after receiving the broadcasting request, traffic jam (and thus collisions) may occur. If a collision occurs, then the involved MSs must re‐send the registration messages. This paper studies the performance of demand re‐registration by investigating how effectively the re‐registration can recover the location record for an MS before the first MS call termination occurs. Our results indicate that demand re‐registration can effectively recover VLR failure.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    International journal of wireless information networks 3 (1996), S. 67-78 
    ISSN: 1572-8129
    Keywords: High-tier ; HLR ; low-tier ; multitier ; PCS ; roaming management ; VLR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The emergence of multitier wireless access is being driven by the different compromises in technology required to provide wireless service in different environments. Three major tiers of wireless access are likely to emerge to providepersonal communications services (PCS): high-tier, low-tier, and unlicensed. Because of the service costs of the three tiers, the unlicensed system is given the highest priority to deliver the calls, and the high-tier system has the lowest priority to deliver the calls. To maintain this delivery priority, two multitier mobility management strategies have been proposed: the single registration strategy (SR) and the modified multiregistration strategy (MR). This paper proposes a new strategy called the lazy deregistration strategy (LDR) and compares the performance of the three strategies. We show that in most cases, LDR outperforms both SR and MR. The registration cost of SR is always no less than the cost of MR. The advantage of MR over SR is more significant if (i) when the user moves into the low-tier system, it is more likely that the currently visited low-tier VLR (visitor location register) is the same as the previously visited VLR, and (ii) the mobile station (MS) is more likely to move between the low-tier system and the high-tier system. The call delivery cost of MR is always no less than the cost of SR. The advantage of SR over MR is more significant if (i) the call arrival rate is large, (ii) the cost of delivering a call to the low-tier system is large, and (iii) the MS is likely to stay in the high-tier system.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Mobile networks and applications 1 (1996), S. 29-38 
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A two-tier PCS system integrates the high tier PCS system and the low tier PCS systems into a single system to provide the advantages of both tiers. Such a system is expected to provide better service (more available and more cost effective to the users) at the expense of the extra tier switching management. We compare the performance of the two-tier PCS system and the single low tier system in two aspects: the registration traffic and the service availability. Because of the tier management, the two-tier system generates more registration traffic than the single low tier system. Under the range of the input parameters in our study, we show that the two-tier system generates less than 10% extra registration traffic than the single low tier system in most cases and generates less than 20% registration traffic in the worst cases. It is clear that for the service availability, the two-tier system is better than the single one tier system. We also study the probability that a call is forced terminated in the single low tier system because the low tier becomes unavailable during the call (such a call can be continued in the two-tier system).
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