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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Frequency Domain Link Adaptation for OFDM-based Cellular Packet Data

Ruberg, Anders January 2006 (has links)
<p>In order to be competitive with emerging mobile systems and to satisfy the ever growing request for higher data rates, the 3G consortium, 3rd Generation Partnership Project (3GPP), is currently developing concepts for a long term evolution (LTE) of the 3G standard. The LTE-concept at Ericsson is based on Orthogonal Frequency Division Multiplexing (OFDM) as downlink air interface. OFDM enables the use of frequency domain link adaptation to select the most appropriate transmission parameters according to current channel conditions, in order to maximize the throughput and maintain the delay at a desired level. The purpose of this thesis work is to study, implement and evaluate different link adaptation algorithms. The main focus is on modulation adaptation, where the differences in performance between time domain and frequency domain adaptation are investigated. The simulations made in this thesis are made with a simulator developed at Ericsson. Simulations show in general that the cell throughput is enhanced by an average of 3% when using frequency domain modulation adaptation. When using the implemented frequency domain power allocation algorithm, a gain of 23-36% in average is seen in the users 5th percentile throughput. It should be noted that the simulations use a realistic web traffic model, which makes the channel quality estimation (CQE) difficult. The CQE has great impact on the performance of frequency domain adaptation. Throughput improvements are expected when using an improved CQE or interference avoidance schemes. The gains with frequency domain adaptation shown in this thesis work may be too small to motivate the extra signalling overhead required. The complexity of the implemented frequency domain power allocation algorithm is also very high compared to the performance enhancement seen.</p>
42

A Comparison between the Swedish 3G Beauty Contest and the UK 3G Auction

Welin, Erik January 2006 (has links)
<p>This thesis compares the two different version of public franchise bidding for awarding 3G licenses used in Sweden and the UK, respectively a beauty contest and an auction. The fact is that the Swedish beauty contest has failed to tackle many of the problems discussed in connection with public franchise bidding in an effective way. Sweden has first of all had problems with enforcing the ambitious coverage criteria. The UK has on the other hand succeeded in tackling the problems and raised governmental revenue of £22.5bn through the auction.</p><p>The conclusion is that this thesis confirms the existing literatures’ critique of the Swedish beauty contest. However, this thesis also provides a new perspective to the existing literature. The main conclusion is that the auction has locked the prices at a high level and externalised negative price and investments effects through the international operators’ behaviour onto consumers in other countries.</p>
43

Voice-over-IP over Enhanced Uplink / Kapacitet för IP-telefoni i den förbättrade WCDMA-upplänken

Brännström, Nils January 2007 (has links)
<p>The traditional voice service in mobile networks is an important service that mobile users expect high quality from. With the convergence of mobile networks towards an all-IP network, an IP-based speech service becomes important which is referred to as Voice-over-IP (VoIP). The traditional voice service is highly optimized and a VoIP service must therefore fulfil strict quality requirements to provide the same speech service quality. The air interface technology, WCDMA, which is used in third generation communication systems in Europe is constantly developed. An improved concept for the mobile-to-network transmission, called the Enhanced Uplink (EUL) provides for higher uplink capacity for packet data services. It also includes features that may provide a sufficient VoIP service quality in mobile networks, when considering the uplink transmission. </p><p>The purpose of this thesis is to evaluate the VoIP capacity over EUL and identify crucial aspects of radio resource management in order to increase the capacity. This is done through dynamic system simulations, using a realistic VoIP traffic model. The VoIP capacity is also estimated by a derived theoretical framework.\newline </p><p>It is shown by simulation results and theoretical estimations, that power control is a vital mechanism in order to increase the capacity. Simulation results indicate that a VoIP over EUL capacity of 65\% of the traditional voice service capacity may be reached. The results also indicate that to improve the capacity for larger cells, the allowed VoIP packet delay must be increased.</p>
44

Hur kan Hi3G öka sitt genomslag på marknaden

Chohan, Norin, Quader, Bornita January 2005 (has links)
No description available.
45

Mobile Multimedia Multicasting in Future Wireless Systems : A Hybrid Cellular-Broadcasting System Approach

Bria, Aurelian January 2008 (has links)
This dissertation addresses the problem of providing a®ordable mobile mul-timedia services in wide area wireless networks. The approach is to con-sider novel system architectures, based on reusing and sharing of the ex-isting network infrastructure for cellular and terrestrial TV broadcastingsystems. The focus has been on the radio resource management techniques,and the evaluation of the potential cost savings, compared to traditionalevolution tracks of the cellular and broadcasting systems.The studies show that deployment cost of a wide area broadcastingnetwork, using DVB-H technology, is very large if high data rate and fullarea coverage is targeted. For this reason we propose to avoid the broad-casting infrastructure dimensioning for full area coverage, and use insteadthe cellular systems to enable error correction for broadcasting transmis-sions. For the special case of mobile users, the chosen approach is to tradesystem's cost and capacity for improved perceived coverage. This trade-o®is enabled by the use of application layer forward error correction, usingRaptor coding.The general purpose Ambient Networks technology was chosen to en-able a platform for inter-operability between cellular and broadcasting sys-tems, especially the necessary interfaces. Under the Ambient Networksframework, we investigate the achievable cost savings o®ered by a hybridcellular-broadcasting system when combinations of broadcast and point-to-point transmissions are jointly utilized to provide ¯le transfers and stream-ing services. Two cases were investigated: one where the cellular systemacts as a replacement and deliver the data in the areas where broadcastingtransmissions cannot reach, and another one where cellular system carriesparity data to users that experience temporary outage in the broadcastingsystem. The results are encouraging, as they show that ¯le transfer costcan be reduced by more than 50%, but only under certain conditions.On a short term, hybrid cellular-broadcasting systems based on 3G andDVB-H, o®er a good platform for testing new and innovative mobile TVservices, enriched with interactivity and content personalization. From atechnical perspective, the outcomes of the presented studies indicate thatfuture systems built on hybrid cellular-broadcasting infrastructures are ableprovide a long term and cost e±cient solution for delivery of a®ordablebroadband multimedia services to mobile users. However, today's cellularand broadcasting systems live in di®erent worlds, are driven by di®erentrevenue models, and they are now starting to compete, instead of cooperate,for controlling the multimedia delivery channels to mobile users. / QC 20100708
46

A Comparison between the Swedish 3G Beauty Contest and the UK 3G Auction

Welin, Erik January 2006 (has links)
This thesis compares the two different version of public franchise bidding for awarding 3G licenses used in Sweden and the UK, respectively a beauty contest and an auction. The fact is that the Swedish beauty contest has failed to tackle many of the problems discussed in connection with public franchise bidding in an effective way. Sweden has first of all had problems with enforcing the ambitious coverage criteria. The UK has on the other hand succeeded in tackling the problems and raised governmental revenue of £22.5bn through the auction. The conclusion is that this thesis confirms the existing literatures’ critique of the Swedish beauty contest. However, this thesis also provides a new perspective to the existing literature. The main conclusion is that the auction has locked the prices at a high level and externalised negative price and investments effects through the international operators’ behaviour onto consumers in other countries.
47

Software-related Energy Footprint of a Wireless Broadband Module

Asplund, Mikael, Thomasson, Anton, Vergara Alonso, Ekhiotz Jon, Nadjm-Tehrani, Simin January 2011 (has links)
Energy economy in mobile devices is becoming an increasinglyimportant factor as the devices become more advancedand rich in features. A large part of the energy footprint of amobile device comes from the wireless communication module,and even more so as the amount of trac increases.In this paper we study the energy footprint of a mobilebroadband hardware module, and how it is aected by software,by performing systematic power consumption measurements.We show that there are several cases where thesoftware does not properly take into account the eect thatdata communication has on the power consumption. Thisopens up for potential energy savings by creating better applicationsthat are aware of the energy characteristics of thecommunication layer.
48

Fjärrstyrning av värmepump

Ericsson, Andreas, Ericsson, Jonas January 2013 (has links)
Att fjärrstyra sin värmepump gör det möjligt att styra inomhusklimatet även då man inte är hemma. Detta passar mycket bra i exempelvis fritidshus då man enkelt kan höja temperaturen innan man skall dit och därmed kan njuta av ett behagligt inomhusklimat direkt. Med dagens fjärrstyrning av Daikins värmepumpar finns två problem. Systemet använder GSM-nätet och användaren måste kunna de olika SMS-koderna utantill. Fjärrstyrning används oftast i fritidshus på landsbygden och 3G-nätet har idag bättre täckning än GSM-nätet på många av dessa platser. Målet med examensarbetet är att ta fram ett system som åtgärdar dessa problem. Vi börjar med att ta fram en funktionsmodell att utgå från. Går vidare med val av hårdvara för modulen, och därefter vidare till mjukvaruutveckling. Resultatet av detta examensarbete är ett system för fjärrstyrning av Daikins värmepumpar som använder 3G-nätet och enkelt kan styras via en androidapplikation.
49

Frequency Domain Link Adaptation for OFDM-based Cellular Packet Data

Ruberg, Anders January 2006 (has links)
In order to be competitive with emerging mobile systems and to satisfy the ever growing request for higher data rates, the 3G consortium, 3rd Generation Partnership Project (3GPP), is currently developing concepts for a long term evolution (LTE) of the 3G standard. The LTE-concept at Ericsson is based on Orthogonal Frequency Division Multiplexing (OFDM) as downlink air interface. OFDM enables the use of frequency domain link adaptation to select the most appropriate transmission parameters according to current channel conditions, in order to maximize the throughput and maintain the delay at a desired level. The purpose of this thesis work is to study, implement and evaluate different link adaptation algorithms. The main focus is on modulation adaptation, where the differences in performance between time domain and frequency domain adaptation are investigated. The simulations made in this thesis are made with a simulator developed at Ericsson. Simulations show in general that the cell throughput is enhanced by an average of 3% when using frequency domain modulation adaptation. When using the implemented frequency domain power allocation algorithm, a gain of 23-36% in average is seen in the users 5th percentile throughput. It should be noted that the simulations use a realistic web traffic model, which makes the channel quality estimation (CQE) difficult. The CQE has great impact on the performance of frequency domain adaptation. Throughput improvements are expected when using an improved CQE or interference avoidance schemes. The gains with frequency domain adaptation shown in this thesis work may be too small to motivate the extra signalling overhead required. The complexity of the implemented frequency domain power allocation algorithm is also very high compared to the performance enhancement seen.
50

A study of security in wireless and mobile payments

Ali, Ahmed January 2010 (has links)
Mobile payments are increasing in popularity in recent years. New mobile solutions are being developed in the form of new Internet capable mobile devices such as the IPhone and new wireless networks such as the LTE and WiMAX networks. This report will present, explain and compare some of the most popular wireless networks that enable mobile payments, from a security point of view. The chosen networks are 3G with connection to GSM, and WLAN networks. The main security mechanisms involved in each network, and how they work will be studied. Security requirements and some of the most important threats each network faces will be presented and discussed. The main purpose of the report is to examine if mobile payments offer an acceptable level of security to the average user.

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