1,353 research outputs found
On soft/hard handoff for packet data services in cellular CDMA mobiles systems
Benefits of macrodiversity operation for packet data services in third generation mobile systems are not obvious. Retransmission procedures to enhance link performance and higher downlink bandwidth requirements could question macrodiversity usage. This paper describes a simple methodology to compare soft and hard handoff performance in terms of transmission delay for packet data services. The handover procedures are based exclusively on power criteria and hysteresis margins.Peer ReviewedPostprint (published version
3G telecommunication technology in Malaysia
3G is the third generation of mobile phone standards and technology, after 2G. It is based on the International Telecommunication Union (ITU) family of standards under the International Mobile Telecommunications programme, "IMT- 2000". 3G technologies enable network operators to offer users a wider range of more advanced services while achieving greater network capacity through improved spectral efficiency. Services include wide-area wireless voice telephony and broadband wireless data, all in a mobile environment. Typically, they provide service at 5-10 Mb per second
EVEREST IST - 2002 - 00185 : D23 : final report
Deliverable pĂșblic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version
Final report on the evaluation of RRM/CRRM algorithms
Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin
4. generĂĄciĂłs mobil rendszerek kutatĂĄsa = Research on 4-th Generation Mobile Systems
A 3G mobil rendszerek szabvĂĄnyosĂtĂĄsa a vĂ©gĂ©hez közeledik, legalĂĄbbis a meghatĂĄrozĂł kĂ©pessĂ©gek tekintetĂ©ben. EzĂ©rt lĂ©tfontossĂĄgĂș azon technikĂĄk, eljĂĄrĂĄsok vizsgĂĄlata, melyek a következĆ, 4G rendszerekben meghatĂĄrozĂł szerepet töltenek majd be. Több ilyen kutatĂĄsi irĂĄnyvonal is lĂ©tezik, ezek közĂŒl projektĂŒnkben a fontosabbakra koncentrĂĄltunk. A következĆben felsoroljuk a kutatott terĂŒleteket, Ă©s röviden összegezzĂŒk az elĂ©rt eredmĂ©nyeket. SzĂłrt spektrumĂș rendszerek KifejlesztettĂŒnk egy Ășj, rĂĄdiĂłs interfĂ©szen alkalmazhatĂł hĂvĂĄsengedĂ©lyezĂ©si eljĂĄrĂĄst. SzimulĂĄciĂłs vizsgĂĄlatokkal tĂĄmasztottuk alĂĄ a megoldĂĄs hatĂ©konysĂĄgĂĄt. A projektben kutatĂłkĂ©nt rĂ©sztvevĆ Jeney GĂĄbor sikeresen megvĂ©dte Ph.D. disszertĂĄciĂłjĂĄt neurĂĄlis hĂĄlĂłzatokra Ă©pĂŒlĆ többfelhasznĂĄlĂłs detekciĂłs technikĂĄk tĂ©mĂĄban. Az elĂ©rt eredmĂ©nyek Imre SĂĄndor MTA doktori disszertĂĄciĂłjĂĄba is beĂ©pĂŒltek. IP alkalmazĂĄsa mobil rendszerekben TovĂĄbbfejlesztettĂŒk, teszteltĂŒk Ă©s ĂĄltalĂĄnosĂtottuk a projekt keretĂ©ben megalkotott Ășj, gyƱrƱ alapĂș topolĂłgiĂĄra Ă©pĂŒlĆ, a jelenleginĂ©l nagyobb megbĂzhatĂłsĂĄgĂș IP alapĂș hozzĂĄfĂ©rĂ©si koncepciĂłt. A tĂ©makörben Szalay MĂĄtĂ© Ph.D. disszertĂĄciĂłja mĂĄr a nyilvĂĄnos vĂ©dĂ©sig jutott. Kvantum-informatikai mĂłdszerek alkalmazĂĄsa 3G/4G detekciĂłra Ăj, kvantum-informatikai elvekre Ă©pĂŒlĆ többfelhasznĂĄlĂłs detekciĂłs eljĂĄrĂĄst dolgoztunk ki. Ehhez Ășj kvantum alapĂș algoritmusokat is kifejlesztettĂŒnk. Az eredmĂ©nyeket nemzetközi folyĂłiratok mellett egy sajĂĄt könyvben is publikĂĄltuk. | The project consists of three main research directions. Spread spectrum systems: we developed a new call admission control method for 3G air interfaces. Project member Gabor Jeney obtained the Ph.D. degree and project leader Sandor Imre submitted his DSc theses from this area. Application of IP in mobile systems: A ring-based reliable IP mobility mobile access concept and corresponding protocols have been developed. Project member MĂĄtĂ© Szalay submitted his Ph.D. theses from this field. Quantum computing based solutions in 3G/4G detection: Quantum computing based multiuser detection algorithm was developed. Based on the results on this field a book was published at Wiley entitled: 'Quantum Computing and Communications - an engineering approach'
Telecommunications Network Planning and Maintenance
Telecommunications network operators are on a constant challenge to provide new services which require ubiquitous broadband access. In an attempt to do so, they are faced with many problems such as the network coverage or providing the guaranteed Quality of Service (QoS). Network planning is a multi-objective optimization problem which involves clustering the area of interest by minimizing a cost function which includes relevant parameters, such as installation cost, distance between user and base station, supported traffic, quality of received signal, etc. On the other hand, service assurance deals with the disorders that occur in hardware or software of the managed network. This paper presents a large number of multicriteria techniques that have been developed to deal with different kinds of problems regarding network planning and service assurance. The state of the art presented will help the reader to develop a broader understanding of the problems in the domain
On the modeling of WCDMA system performance with propagation data
The aim of this study was to develop calculation methods for estimating the most important system level performance characteristics of the WCDMA radio network (i.e. network capacity and coverage) in the presence of interference from various sources. The calculation methods described in this work enable the fast design of radio systems with a reasonable degree of accuracy, where different system parameters, propagation conditions and networks as well as frequency scenarios can be easily tested. The work also includes the development and verification of a propagation model for a microcellular environment.
Traditionally, system level performance figures have been retrieved using system simulations where the radio network has been modeled as accurately as possible. This has included base stations and mobile stations, propagation models, traffic models and mobility models. Various radio resource management (RRM) algorithms, such as power controls and handovers have also been modeled. However, these system simulations are very complex and time consuming and typically the models are difficult to modify. The idea behind this work is to use the main statistical parameters retrieved from accurate, case specific propagation models and to use these statistics as input for the developed analytical radio network models. When used as output from these analytical models we are able to obtain the performance measures of the network.
The specific application area for the developed methods is the evaluation of the effect of the interference from the adjacent frequency channels. Adjacent channel interference decreases the efficiency of the usage of the electromagnetic spectrum i.e. the spectral efficiency. The aim of a radio system design is to ensure that the reduction in the spectral efficiency is as low as possible. This interference may originate from the same or a different radio system and from the same or another operator's network. The strength of this interference is dependent on the system parameters and the network layout.
The standard questions regarding adjacent system interference between different operators' network are what guard band is needed between the radio carriers in order to maintain the quality of the network or what are the main mobile and network parameters, such as adjacent channel emission levels or adjacent channel selectivity, required in order to achieve satisfactory network performance. With the developed method proposed here it is possible to answer these questions with reasonable accuracy.
One important aspect of network performance is the radio wave propagation environment for which the radio systems are designed. This thesis presents methods evaluating radio wave propagation, especially for cases where the base station antenna is below the rooftops, i.e. in the case of microcellular network environments. The developed microcellular propagation model has been developed for network planning purposes and it has been verified using numerous field propagation measurements. The model can be used in cases where the mobile station is located either indoors or outdoors.reviewe
Soft handover issues in radio resource management for 3G WCDMA networks
PhDMobile terminals allow users to access services while on the move. This unique
feature has driven the rapid growth in the mobile network industry, changing it from a
new technology into a massive industry within less than two decades.
Handover is the essential functionality for dealing with the mobility of the mobile
users. Compared with the conventional hard handover employed in the GSM mobile
networks, the soft handover used in IS-95 and being proposed for 3G has better
performance on both link and system level.
Previous work on soft handover has led to several algorithms being proposed and
extensive research has been conducted on the performance analysis and parameters
optimisation of these algorithms. Most of the previous analysis focused on the uplink
direction. However, in future mobile networks, the downlink is more likely to be the
bottleneck of the system capacity because of the asymmetric nature of new services,
such as Internet traffic.
In this thesis, an in-depth study of the soft handover effects on the downlink
direction of WCDMA networks is carried out, leading to a new method of optimising
soft handover for maximising the downlink capacity and a new power control
approach
MODELS FOR GREENFIELD AND INCREMENTAL CELLULAR NETWORK PLANNING
Mobility, as provided in cellular networks, is largely affected by the location of the base stations. To a large extent, the location of base stations is determined by the quantity of base stations available to provide coverage. It is therefore not surprising that the quantity and subsequent location of base stations will not only impact service delivery but also have a large associated cost for implementation. Generally, the higher the quantity of base stations required to provide coverage, the greater the cost of implementation and operation of the radio network. This thesis proposes a modified optimization model to aid the cell planning process. This model, unlike those surveyed, is applicable to both green field and incremental network designs. The variation in model design is fundamental in ensuring cost effective growth and expansion of cellular networks. Numerical studies of the modified model applied to both abstract and real system configurations are carried out using MATLAB. Terrain data from Kampala, Uganda, was used to aid the study. Results show that the antenna height significantly determines the solution of the objective function. In addition, it is shown that slight variations in the cost association between the antenna height and the site construction requirements can be decisively used for predefined targeted network planning. A comparison is also made between an actual network installation and the estimates provided by the model. As expected, results from the study show that the difference between the estimated count and the actual count can be adEquately minimized by slight variations in antenna height requirements
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