<p>The key idea of the new, shared high-capacity channel HSDPA, is to adapt the transmission rate to fast variations in the current radio conditions, thus enabling download peak data rates much higher than what WCDMA can offer today. This has induced a need for data that traverses the mobile network to be intermediately buffered in the Radio Base Station, RBS. A scheduling algorithm then basically selects the user with the most beneficial instantaneous radio conditions for access to the high-speed channel and transmission of its data over the air interface.</p><p>The purpose of this thesis is to design a flow control algorithm for the transmission of data packets between the network node directly above the RBS, the RNC, and the RBS. This flow control algorithm should keep the level of the buffers in the RBS on such a level that the air interface may be fully utilized. Yet it is not desirable with large buffers since e.g., this induces longer round-trip times as well as loss of all data in the buffers whenever the user moves to another cell and a handover is performed. Theoretical argumentations and simulations show that both of these requirements may be met, even though it is a balancing act.</p><p>Suggested is a control-theoretic framework in which the level in the RBS buffers are kept sufficiently large by taking into account predictions of future outflow over air and by using methods to compensate for outstanding data on the transport network. This makes it possible to keep the buffer levels stable and high enough to fully utilize the air interface. By using a more flexible adaptive control algorithm, it is shown possible to reach an even higher utilization of the air interface with the same or even lower buffering, which reduces the amount of data lost upon handovers. This loss is shown to be even more reduced by actively taking system messages about upcoming handover events into account as well.</p>

<p>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.</p><p>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.</p>

<p>Företaget Flextronics AB i Linköping testar moderna mobiltelefoner för tillverkares räkning. Som examensarbete har jag fått företagets uppdrag att utvärdera och förbättra deras testsystem DVT-UMTS (3G).</p><p>DVT-UMTS är ett komplext system av komponenter, och man misstänker att dessa stör varandra inbördes, vilket i sin tur kan ge felaktiga mätresultat.</p><p>Beträffande mottagarsidan hos en mobiltelefon tror man att DVT-UMTS p g a störningar, s k intermodulationsprodukter, uppvisar bitfelshalter i testet Rx Out of band blocking. Komponenter som kan tänkas ge störningar är continuous wave-generator och basstationssimulatorn. Antennanslutningen bortses från i undersökningen. Kontroll av CW-generatorn sker med hjälp av lågpassfilter, riktkopplare och dämpare. Kontrollen visar att den är orsak till bitfel men inte ensam orsak. Basstationssimulatorn kontrolleras med hjälp av högpassfilter, riktkopplare och varierade kabellängder. Även denna visar sig ge upphov till bitfel.</p><p>Bitfel orsakade av intermodulationsprodukter från CW-generatorn kan reduceras med lågpassfilter och dämpare. Motsvarande problem hos basstationssimulatorn kan åtgärdas med högpassfilter och varierade kabellängder.</p><p>Kvarstående bitfel är acceptabla enligt specificerade krav från det internationella samarbetsorganet 3GPP.</p><p>Mobiltelefonens sändarefunktion testas med programmet Tx Spurious emission, där otillåtet höga dämpningsnivåer kan ge problem. Dessa nivåer beror av signalvägarna mellan testad enhet och spektrumanalysatorn. Med hjälp av gordon, darlingtontransistor och switch kan signalvägarna optimeras. En alternativ testuppkoppling på DVT-UMTS, innehållande switch med styrprogram, ger dämpningsnivåer innanför specificerade gränser.</p>

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.

During the 2nd generation Global System for Mobile Communications (GSM) mobile communication, the focus of the mobile positioning was mostly on call setup and messaging. But the evolution of the 3rd generation Wideband Code Division Multiple Access (WCDMA) has changed the focus of mobile positioning. With the increase use of smart phones the mobile positioning is now extensively used for location based services (LBS’s). Mobile positioning becomes extremely important when the user requests any particular LBS, because it directly affects the communication and resource handling between the network and the mobile user MU. In order to reduce cost of messages exchange between the network and the MU it is really important that network should know the location of MU with minimum error. There are many positioning methods that are used today for MU location estimation. In this thesis database correlation method (DCM) is used as a positioning technique to estimate the MU location in the Universal Mobile Telecommunication System UMTS network. The thesis will also explain different penalty techniques for different scenarios that could be used to improve the MU location accuracy in the urban environment. By applying different penalty techniques the best positioning accuracy achieved for 67% of the measurements varies is 88m and for 95% it is 153m. Other penalty techniques results will be compared at the end in order to find the best penalty techniques that offer much improved location accuracy for MU.

The use of mobile devices is increasing due to the constant development of more advanced and appealing applications and computing features. However, these new features are very power hungry leading to short battery lifetimes. Research shows that a major reason for fast battery depletion is the excessive and inefficient use of the wireless interfaces. This thesis studies how we can attempt to increase the battery lifetime of the devices without having to sacrifice the usage of these advanced features in some applications. The thesis focuses on adapting the traffic pattern characteristics of mobile communication using a widespread wireless communication technology like 3G. Traffic pattern adaptation is performed at packet level in kernel space in Android. The data transfers are scheduled with the knowledge of the energy consumption characteristics of 3G. The performed measurements indicate that our solution can provide energy savings ranging from 7% to 59%. This work confirms that 3G conscious scheduling of network traffic reduces energy consumption, and that, both applications and energy saving libraries are potential directions to be further studied.

The key idea of the new, shared high-capacity channel HSDPA, is to adapt the transmission rate to fast variations in the current radio conditions, thus enabling download peak data rates much higher than what WCDMA can offer today. This has induced a need for data that traverses the mobile network to be intermediately buffered in the Radio Base Station, RBS. A scheduling algorithm then basically selects the user with the most beneficial instantaneous radio conditions for access to the high-speed channel and transmission of its data over the air interface. The purpose of this thesis is to design a flow control algorithm for the transmission of data packets between the network node directly above the RBS, the RNC, and the RBS. This flow control algorithm should keep the level of the buffers in the RBS on such a level that the air interface may be fully utilized. Yet it is not desirable with large buffers since e.g., this induces longer round-trip times as well as loss of all data in the buffers whenever the user moves to another cell and a handover is performed. Theoretical argumentations and simulations show that both of these requirements may be met, even though it is a balancing act. Suggested is a control-theoretic framework in which the level in the RBS buffers are kept sufficiently large by taking into account predictions of future outflow over air and by using methods to compensate for outstanding data on the transport network. This makes it possible to keep the buffer levels stable and high enough to fully utilize the air interface. By using a more flexible adaptive control algorithm, it is shown possible to reach an even higher utilization of the air interface with the same or even lower buffering, which reduces the amount of data lost upon handovers. This loss is shown to be even more reduced by actively taking system messages about upcoming handover events into account as well.

A current trend in the information society is that traditionally fixed computing resources are made available to mobile users. Most of the existing techniques for communication have been developed for stationary computing, and they must be adapted to the different connection properties of the mobile environment. One of the emerging mobile computing environments is the Universal Mobile Telecommunication System, UMTS. This system places demands on the quality of service that is provided to data flows, which requires resource management in the connection network. The most scarce resources in this system is the radio resources. The easiest way to conduct research in new and adapted techniques for communication is to perform simulations. Management of resources places restrictions on connections, and to get reliable results during simulations it must be included in the simulated environment. The thesis discusses and builds a basis for development of UMTS radio resource management in the network simulator ns-2. A limited version of UMTS radio resource management is added to ns-2 and evaluated.

Företaget Flextronics AB i Linköping testar moderna mobiltelefoner för tillverkares räkning. Som examensarbete har jag fått företagets uppdrag att utvärdera och förbättra deras testsystem DVT-UMTS (3G). DVT-UMTS är ett komplext system av komponenter, och man misstänker att dessa stör varandra inbördes, vilket i sin tur kan ge felaktiga mätresultat. Beträffande mottagarsidan hos en mobiltelefon tror man att DVT-UMTS p g a störningar, s k intermodulationsprodukter, uppvisar bitfelshalter i testet Rx Out of band blocking. Komponenter som kan tänkas ge störningar är continuous wave-generator och basstationssimulatorn. Antennanslutningen bortses från i undersökningen. Kontroll av CW-generatorn sker med hjälp av lågpassfilter, riktkopplare och dämpare. Kontrollen visar att den är orsak till bitfel men inte ensam orsak. Basstationssimulatorn kontrolleras med hjälp av högpassfilter, riktkopplare och varierade kabellängder. Även denna visar sig ge upphov till bitfel. Bitfel orsakade av intermodulationsprodukter från CW-generatorn kan reduceras med lågpassfilter och dämpare. Motsvarande problem hos basstationssimulatorn kan åtgärdas med högpassfilter och varierade kabellängder. Kvarstående bitfel är acceptabla enligt specificerade krav från det internationella samarbetsorganet 3GPP. Mobiltelefonens sändarefunktion testas med programmet Tx Spurious emission, där otillåtet höga dämpningsnivåer kan ge problem. Dessa nivåer beror av signalvägarna mellan testad enhet och spektrumanalysatorn. Med hjälp av gordon, darlingtontransistor och switch kan signalvägarna optimeras. En alternativ testuppkoppling på DVT-UMTS, innehållande switch med styrprogram, ger dämpningsnivåer innanför specificerade gränser.

In this thesis we introduce a half-wavelength loop antenna for operation as an internal antenna for mobile phones. First, we introduce a single loop antenna for single-band operation (eg., UMTS band), and experimental and simulated results are presented. Next, we introduce a dual-band loop structure which covers the operating bandwidths of the GSM/DCS dual-band mobile phone. The proposed dual-loop antenna is studied, especially for the effects between the two loops of the antenna. Both of the single-loop and dual-loop antennas have the characteristics of generating similar surface currents on the ground plane with that of the conventional monopole and planar inverted-F mobile phone antennas.