Signaling Load Research Articles

Paging area planning in future cellular systems

AbstractEfficient resource utilisation in future cellular systems is related to the control of the signalling load imposed by the paging operations. This relies on the application of efficient paging schemes, and on the “proper” planning of paging areas. In this paper we define and solve a version of the paging area planning problem. In particular, we provide a low complexity algorithm, under the assumption that the scheme applied falls within the last interaction based paging (LIBP) category.

ACM SIGCOMM computer communication review

At some point in the future, how far out we do not exactly know, wireless access to the Internet will outstrip all other forms of access bringing the freedom of mobility to the way we access the we...

Analysis of the WAP protocol over SMS in GSM networks

AbstractThis paper, based on the PALIO Project within the fifth Research Framework of the European Commission, deals with an information tourist service accessible through mobile phones by means of the Wireless Application Protocol (WAP). We have considered a Global System for Mobile communications (GSM) network where the WAP traffic is transported by the Short Message Service (SMS) on a logical channel that also conveys signaling messages. Suitable models have been considered for both WAP browsing traffic and signaling traffic. We have proposed a theoretical approach to evaluate the mean delay to browse a WAP page taking into account the impact of the signaling load. Analytical predictions have been validated through comparisons with simulation results. Moreover, we have also considered a specific Quality of Service (QoS) requirement in terms of the maximum deck transmission delay that is guaranteed in 95 per cent of cases. Consequently, it has been possible to evaluate the number of WAP users that can be supported per cell. The study carried out in this paper permits to prove the feasibility for the envisaged mobile service based on WAP and it also allows dimensioning WAP pages so that each user experiences reasonable browsing delays. Copyright © 2001 John Wiley & Sons, Ltd.

Group location tracking based on representative identity and virtual VLR for transportation systems

A location tracking scheme known as group location tracking (GLT) is proposed to reduce the location update cost for terrestrial transportation systems (TSs) in personal communication networks. When a TS moves into a new registration area, the GLT scheme, based on a representative identity of the TS and a virtual visitor location register, updates location information by a group location update request message instead of individual location update of users. Compared with the IS-41, the GLT scheme significantly reduces signaling load.

Stochastic control of path optimization for inter-switch handoffs in wireless ATM networks

One of the major design issues in wireless ATM networks is the support of inter-switch handoffs. An inter-switch handoff occurs when a mobile terminal moves to a new base station connecting to a different switch. Apart from resource allocation at the new base station, inter-switch handoff also requires connection rerouting. With the aim of minimizing the handoff delay while using the network resources efficiently, the two-phase handoff protocol uses path extension for each inter-switch handoff, followed by path optimization if necessary. The objective of this paper is to determine when and how often path optimization should be performed. The problem is formulated as a semi-Markov decision process. Link cost and signaling cost functions are introduced to capture the tradeoff between the network resources utilized by a connection and the signaling and processing load incurred on the network. The time between inter-switch handoffs follows a general distribution. A stationary optimal policy is obtained when the call termination time is exponentially distributed. Numerical results show significant improvement over four other heuristics.

Extending mobile IP with adaptive individual paging

This paper proposes to extend Mobile IP with adaptive individual paging. Paging reduces the signaling cost of Mobile IP making it more adapted to wireless cellular IP networks. By reducing the number of location updates to be sent per mobile host, paging also minimizes power consumption of the mobile devices. In the proposed extension, each mobile host computes dynamically its optimal location area size according to its traffic and mobility parameters. The optimal size is the size that provides the best paging versus location update cost tradeoff and, as a result, minimizes the signaling load in the network. We compare, by simulation, the performance of the proposed scheme with that of Mobile IP [11], a paging scheme that uses fixed size location areas and Hierarchical Mobile IP [5]. We show that our extension provides a significant gain compared to Mobile IP and the fixed size paging scheme and performs as well and sometimes better than Hierarchical Mobile IP. We also show that the integration of adaptive individual paging within Hierarchical Mobile IP outperforms all schemes.

INTELLIGENT PAGING STRATEGIES FOR THIRD GENERATION PERSONAL COMMUNICATION SERVICES NETWORKS

We consider the problem of minimizing paging cost, subject to delay constraint, in Personal Communication Services Network (PSCN) and present two intelligent paging strategies for third generation systems. They are termed as sequential intelligent paging (SIP) and parallel-o-sequential intelligent paging (PSIP). Unlike the conventional blanket paging where all cells in a location area are polled at a time, in SIP (PSIP) one cell (a group of cells) is polled at a time. The proposed schemes lead to a decrease in paging signaling load at the cost of some extra processing power. When better discovery rate per cycle is expected irrespective of the incoming traffic PSIP is always preferred to other paging schemes primarily because of its less amount of polling delay. If the incoming traffic rate is low, SIP performs better than PSIP in terms of paging cost per cycle. However, the polling costs per cycle and the discovery rates for both the schemes become equal as number of paging requests per cycle increases. An improvement in respect of paging cost per cycle and discovery rate over conventional paging is shown with the help of simulation results.

Analysis of link cost functions for PNNI routing

The emerging environment of ATM networks with unpredictable traffic patterns and ever-changing network configurations create the need for using dynamic routing methods. Dynamic routing basically means that path selection continuously adapts to the state of the network. The routing framework of the Private Network-to-Network Interface (PNNI) specification achieves this by using link-state information gathered from the network. One possible approach for selecting paths is to use a shortest path algorithm (e.g., Dijkstra's) with link costs generated from the link load information. This mapping is realised by the so-called link cost function. We investigated a number of such link cost functions with simulation. We developed two novel link cost functions and compared them with those found in the literature. The primary basis of comparison was the total throughput of the networks. Besides this, we also investigated such issues as imposed signalling load and robustness.

Computationally efficient algorithms for location area planning in future cellular systems

Efficient resource utilisation in future cellular systems is related to the control of the signalling load imposed by the location update and paging operations. Important means for controlling this load is the “proper” planning of location areas. In this paper we define and solve a version of the location area planning problem. Starting from a formal definition and an optimal formulation of the problem, three computationally efficient algorithms, adhering to simulated annealing, taboo search, and genetic algorithm paradigm, are presented.

Mobile agent and CORBA technologies in the broadband intelligent network

This article presents an IN architecture that is based on distributed object and mobile agent technologies. It deviates from traditional IN in two prominent ways: first, by substituting message-based protocols with a CORBA distributed processing environment. The new communications infrastructure not only serves to convey IN flows, but also functions as a potent unifying location-transparent layer. Second, the new architecture makes heavy use of mobile agent technology. Service logic programs are implemented as mobile agents, and are thus not constrained to control the switch's operations remotely from a central location. Instead, they can migrate and control its operations locally. The infrastructure elements of the architecture exploit this ability of service logic programs by cloning them and dragging their clones to the appropriate locations in response to excess processing or signaling load. The architecture is in this way self-balancing, in contrast to the centralized nature of traditional IN. A prototype implementation is presented along with a service creation framework that enables the IN service designer to disregard environment-related issues and concentrate on the IN logic of the services per se.

Adaptive quality of service handoff priority scheme for mobile multimedia networks

For various advantages including better utilization of radio spectrum (through frequency reuse), lower mobile transmit power requirements, and smaller and cheaper base station equipment, future wireless mobile multimedia networks are likely to adopt micro/picocellular architectures. A consequence of using small cell sizes is the increased rate of call handoffs as mobiles move between cells during the holding times of calls. In a network supporting multimedia services, the increased rate of call handoffs not only increases the signaling load on the network, but makes it very difficult for the network to guarantee the quality of service (QoS) promised to a call at setup or admission time. This paper describes an adaptive QoS handoff priority scheme which reduces the probability of call handoff failures in a mobile multimedia network with a micro/picocellular architecture. The scheme exploits the ability of most multimedia traffic types to adapt and trade off QoS with changes in the amount of bandwidth used. In this way, calls can trade QoS received for fewer handoff failures. The call level and packet level performance of the handoff scheme are studied analytically for a homogeneous network supporting a mix of wide-band and narrow-band calls. Comparisons are made to the performance of the nonpriority handoff scheme and the well-known guard-channel handoff scheme.

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.

Intelligent location tracking strategy in PCS

Ai1 alternative stntegy (AS) for reducing location update signalling load has hc11 yroposcd 10 improve the classical strategy (CS) used in the Global System for Mobile Communications (GSM). Bowevet, the AS is suitablc only Ibr long-term events and fixed movement tracks. Location tracking (paging) costs more when tlic rnobilc host (MH) changes iiiovcment habits or cncoiinlcrs short-term events. A novel method is proposcd that aims to reduce signalling load resulting from location tracking in ihc above situations. The key idea is to takc iiscr rccciit inoveinent information (called the paging idormioI1 rccordj into account to detenninc which location area to page first. Performance evaluation has been conducted using ii city area zone modcl that can model H redistic city area environment. Expcrimcnlal rcsults show that the method can rcducc location munagement signillling costs by 1655% and 639% conipared to CS and AS, rcslxctivcly. The overhead of the :ipproach is the additional storage spacc rcquired (for storing MH procilcs and pdgitig infonnalion rccords) and the additionel processing time. Howcvcr, Lhc overhead is insignificant in terms of loday's memoly ctipacity and processor speed, and Ihc r'cduction in signalIing load makcs tnorc bandwidth available.

Performance analysis of cross- and cigar-shaped urban microcells considering user mobility characteristics

User mobility characteristics and cell shapes in urban microcellular environments are different from those in macrocellular environments because pedestrians walk along streets and radio signals are guided by tall buildings lining both sides of the streets. Urban area microcell shapes follow approximately the street pattern. In this paper, we characterize low-tier user mobility in typical urban microcells: cross-shaped cells and cigar-shaped cells, and then evaluate and compare the two types of microcells. The results show that the more suitable cell shape with respect to handoff traffic and its signaling load is determined by the probability of straight movement at an intersection. On the other hand, blocking probability in low-tier microcells mainly depends on the cell size, not the shape. This framework and its numerical results can be utilized in determining the cell shape and size of urban microcellular systems.

時変係数システムにおける一般化最小分散制御を用いたサーボ系設計

Output predictions of Generalized Minimum Variance Control (GMVC) are obtained by solving the Diophantine Equation based on the present model parameters. Therefore, exact value of prediction would not be calculated for time-varying system changing model parameter fast. In this paper, we show output predictor and control law of GMVC on the basis of Generalized Predictive Control (GPC) for time-varying system suggested by O. P. Palsson et al. (1993). And further, we investigate properties of GMVC for time-varying system. In order to avoid consuming the vast energy, in general, the control-weighting of cost function is given as a positive value. But this may cause the offset in the output of the system. Also, the offset may occur because of input disturbance. To eliminate these offsets, in this research, the technique that establishes a compensator based on the internal model principle is proposed, that is the servo system materialized against the reference signal change and load disturbance.

An architecture of ATM-based PCS network: Signaling traffic and capacity

In this paper, we propose an ATM?based Personal Communication Service (PCS) network architecture with ring?based access networks. We also propose a simple ring management scheme using ATM Add?Drop?Multiplexers (ADM). The ring has a Virtual Star topology, and we manage its bandwidth at two levels: Virtual Path (VP) level and Virtual Channel (VC) level. We consider four different types of configurations according to the locations of visitor location register (VLR) and mobile switching center (MSC) functions, and obtain signaling load and processing load. A 150 Mb/s?dual ring can support about 5,500 homogeneous ON---OFF voice sources. This ring capacity corresponds to covering approximately 180 cells in the case of 30 connections per cell. Even though we are here concerned with evaluating the proposed network for voice traffic, we can extend this study to the analysis of the proposed ATM?based PCS network accommodating various types of multimedia traffic as a further study.

Paging and location update algorithms for cellular systems

Several alternative strategies for reducing paging and location update costs have been proposed lately. This paper initially compares four well-known strategies, that differ in the manner they approach that problem. The same mobility model and performance evaluation criteria were used for all strategies analyzed. Users are classified utilizing the call-to-mobility-ratio (CMR) metric. Results are given weighting in different ways the signaling cost in the radio interface and in the fixed network part. Based on the results obtained, this paper also introduces an alternative paging and location update algorithm. The subscriber call patterns and its mobility profile are used to define the size and shape of the location areas. Further analysis showed that this technique yields a significant signaling load reduction.

LATS: a load-adaptive threshold scheme for tracking mobile users

Mobile user tracking is a major issue. We propose a novel approach for user tracking, in which the tracking activity is adapted to both user and system activity. The basic idea is to make the user-location update-rate dependent not only on the user activity (such as the call profile and mobility pattern). Rather, it is also made dependent on the signaling load, which reflects the actual cost of the update operation. Thus, at low-signaling load locations, the users are to transmit location update messages more frequently. To carry out this approach, we propose a load-adaptive threshold scheme (LATS): the network determines for each cell a registration threshold level (which depends on the cell load) and announces it, as a broadcast message, to the users. The user computes its own registration priority and then transmits a registration message only if its priority exceeds the announced threshold level. Thus, whenever the local load on the cell is low, the registration activity increases, while in loaded cells the registration activity decreases. Our analysis shows that the LATS reduces the paging cost, in comparison with other dynamic methods, without increasing the wireless cost of registration. Moreover, if higher user density is coupled with less mobility (e.g., consider vehicles), then the LATS strategy offers further performance improvement. The load-adaptive strategy can be used in addition to any other dynamic tracking strategy. Furthermore, the computational complexity imposed on the user is identical to that required by an equivalent load-insensitive scheme.

Reuse partitioning in cellular networks in dynamic channel allocation

Great interest in recent years has been devoted to mobile communications. The research effort has been directed to increasing the capacity of radio systems by applying space reuse techniques. Higher efficiency in the usage of the available frequency spectrum can be obtained either by reducing the cell size, thus requiring the provision of new base stations, or by reusing the available spectrum more efficiently without cell size reduction. In this paper we present a dynamic frequency allocation algorithm for cellular networks that exploits a given reuse pattern. The performance of the proposed scheme, in terms of blocking probability, is evaluated by means of computer simulations both when the position of the mobiles remains unchanged and when mobility is taken into account, under both uniform and hot-spot traffic. The numerical results show that the capacity of the proposed scheme is sensibly higher than that of a dynamic channel allocation without reuse partitioning. The effects of both user mobility and reuse partitioning on the signalling load are also considered.

RF-model extraction for passive components on MCM-Si materials

Silicon based Multi Chip Module (MCM-Si) technology offers high precision and high packing density compared with traditional PCB and ceramic thick film hybrid technologies. When used in RF-equipment, MCM-Si’s suffer from severe signal loading and signal coupling via the substrate. In this paper modeling of passive elements on MCM’s is discussed. Simple equivalent circuits and parameter extraction methods are presented.