186 research outputs found

    Dynamic half-rate connections in GSM

    Get PDF

    Dynamic half-rate connections in GSM

    Get PDF

    Innovation in the Wireless Ecosystem: A Customer-Centric Framework

    Get PDF
    The Federal Communications Commission’s Notice of Inquiry in GN 09-157 Fostering Innovation and Investment in the Wireless Communications Market is a significant event at an opportune moment. Wireless communications has already radically changed the way not only Americans but people the world over communicate with each other and access and share information, and there appears no end in sight to this fundamental shift in communication markets. Although the wireless communications phenomenon is global, the US has played and will continue to play a major role in the shaping of this market. At the start of a new US Administration and important changes in the FCC, it is most appropriate that this proceeding be launched.

    A study of teletraffic problems in multicast networks

    Get PDF
    This dissertation studies teletraffic engineering of dynamic multicast connections. The traditional models in teletraffic engineering do not handle multicast connections properly, since in a dynamic multicast tree, users may join and leave the connection freely, and thus the multicast tree evolves in time. A model called multicast loss system is used to calculate blocking probabilities in a single link and in tree-type networks. In a single link case, the problem is a generalised Engset problem, and a method for calculating call blocking probabilities for users is presented. Application of the reduced load approximation for multicast connections is studied. Blocking probabilities in a cellular system are studied by means of simulation. The analysis is mainly concentrated on tree type networks, where convolution-truncation algorithms and simulation methods for solving the blocking probabilities exactly are derived. Both single layer and hierarchically coded streams are treated. The presented algorithms reduce significantly the computational complexity of the problem, compared to direct calculation from the system state space. An approximative method is given for background traffic. The simulation method presented is an application of the Inverse Convolution Monte-Carlo method, and it gives a considerable variance reduction, and thus allows simulation with smaller sample sizes than with traditional simulation methods. Signalling load for dynamic multicast connections in a node depends on the shape of the tree as well as the location of the node in the tree. This dissertation presents a method for calculating the portion of signalling load that is caused by call establishments and tear-downs.reviewe

    Actual call connection time characterization for wireless mobile networks under a general channel allocation scheme

    Full text link

    Mobility modeling and management for next generation wireless networks

    Get PDF
    Mobility modeling and management in wireless networks are the set of tasks performed in order to model motion patterns, predict trajectories, get information on mobiles\u27 whereabouts and to make use of this information in handoff, routing, location management, resource allocation and other functions. In the literature, the speed of mobile is often and misleadingly referred to as the level of mobility, such as high or low mobility. This dissertation presents an information theoretic approach to mobility modeling and management, in which mobility is considered as a measure of uncertainty in mobile\u27s trajectory, that is, the mobility is low if the trajectory of a mobile is highly predictable even if the mobile is moving with high speed. On the other hand, the mobility is high if the trajectory of the mobile is highly erratic. Based on this mobility modeling concept, we classify mobiles into predictable and non-predictable mobility classes and optimize network operations for each mobility class. The dynamic mobility classification technique is applied to various mobility related issues of the next generation wireless networks such as location management, location-based services, and energy efficient routing in multihop cellular networks

    Traffic analysis and modeling in PMR systems

    Get PDF
    Cataloged from PDF version of article.Reliable knowledge of traffic in PMR (Private Mobile Radio) systems is essential for assessing the issues in migration from analog to digital and trunked PMR systems. In this work, we investigated two concepts. First, we modeled the service time distribution of conventional PMR networks by using teletraffic data of a conventional PMR network. It is found that the density of the service time is a shifted exponential which is delayed by 0.7 second. The mean service time is about 2.5 seconds. We showed that voice call arrivals to a transmission trunked PMR network are not Poisson distributed. Analytical and simulation methods based on M/G/C (a C server queue with Poisson input and general service) models may not model the system as well as G/G/C (a C server queue with general input and general service) models. Several trunked PMR systems have been designed over the last decade, most of which have symmetric downlink and uplink channel capacities. These systems may not be spectrally efficient in case of group or broadcast-based voice and data calls, a common feature of PMR systems. Second, we studied a new asymmetric PMR system comprising of a wideband OFDM (Orthogonal Frequency Division Multiplexing)-based downlink, such as Digital Audio Broadcasting (DAB) system. We found that for 2 % GoS and a mean service time of 2.86 second, PMR users that can be supported by the proposed system is 315000.Can, BaşakM.S

    Teletraffic engineering and network planning

    Get PDF

    Elastic calls in an integrated services network: the greater the call size variability the better the QoS

    Get PDF
    We study a telecommunications network integrating prioritized stream calls and delay tolerant elastic calls that are served with the remaining (varying) service capacity according to a processor sharing discipline. The remarkable observation is presented and analytically supported that the expected elastic call holding time is decreasing in the variability of the elastic call size distribution. As a consequence, network planning guidelines or admission control schemes that are developed based on deterministic or lightly variable elastic call sizes are likely to be conservative and inefficient, given the commonly acknowledged property of e.g.\ \textsc{www}\ documents to be heavy tailed. Application areas of the model and results include fixed \textsc{ip} or \textsc{atm} networks and mobile cellular \textsc{gsm}/\textsc{gprs} and \textsc{umts} networks. \u
    corecore