Real-time video communication over wireless networks is a challenging problem because wireless channels suffer from fading, additive noise and interference, which translate into packet loss and delay. Since modern video encoders deliver video packets with decoding dependencies, packet loss and delay can significantly degrade the video quality at the receiver. Many error resilience mechanisms have been proposed to combat packet loss in wireless networks, but only a few were specifically designed for packet switched video telephony over Third Generation (3G) networks. The first part of the thesis presents an error resilience technique for packet switched video telephony that combines application layer Forward Error Correction (FEC) with rateless codes, Reference Picture Selection (RPS) and cross layer optimization. Rateless codes have lower encoding and decoding computational complexity compared to traditional error correcting codes. One can use them on complexity constrained hand-held devices. Also, their redundancy does not need to be fixed in advance and any number of encoded symbols can be generated on the fly. Reference picture selection is used to limit the effect of spatio-temporal error propagation. Limiting the effect of spatio-temporal error propagation results in better video quality. Cross layer optimization is used to minimize the data loss at the application layer when data is lost at the data link layer. Experimental results on a High Speed Packet Access (HSPA) network simulator for H.264 compressed standard video sequences show that the proposed technique achieves significant Peak Signal to Noise Ratio (PSNR) and Percentage Degraded Video Duration (PDVD) improvements over a state of the art error resilience technique known as Interactive Error Control (IEC), which is a combination of Error Tracking and feedback based Reference Picture Selection. The improvement is obtained at a cost of higher end-to-end delay. The proposed technique is improved by making the FEC (Rateless code) redundancy channel adaptive. Automatic Repeat Request (ARQ) is used to adjust the redundancy of the Rateless codes according to the channel conditions. Experimental results show that the channel adaptive scheme achieves significant PSNR and PDVD improvements over the static scheme for a simulated Long Term Evolution (LTE) network. In the third part of the thesis, the performance of the previous two schemes is improved by making the transmitter predict when rateless decoding will fail. In this case, reference picture selection is invoked early and transmission of encoded symbols for that source block is aborted. Simulations for an LTE network show that this results in video quality improvement and bandwidth savings. In the last part of the thesis, the performance of the adaptive technique is improved by exploiting the history of the wireless channel. In a Rayleigh fading wireless channel, the RLC-PDU losses are correlated under certain conditions. This correlation is exploited to adjust the redundancy of the Rateless code and results in higher Rateless code decoding success rate and higher video quality. Simulations for an LTE network show that the improvement was significant when the packet loss rate in the two wireless links was 10%. To facilitate the implementation of the proposed error resilience techniques in practical scenarios, RTP/UDP/IP level packetization schemes are also proposed for each error resilience technique. Compared to existing work, the proposed error resilience techniques provide better video quality. Also, more emphasis is given to implementation issues in 3G networks.

近年來，手機市場的年齡層有日漸年輕化的趨勢，人手一機、人手兩機早已成為台灣普遍之現象。而更多、更新穎的手機陸續推出，各家電信業者以及手機廠商不斷推陳出新，手機的功能已經從只有撥打、接聽的陽春功能，到了現在可以無線上網、數位相機…等的強大功能，手機早已經不再只是手機。 本研究主要以電話調查來探討國內手機3G市場之未來趨勢，了解台灣手機消費者對3G手機的需求性，以及對3G手機有何訴求，進一步以Microsoft SQL Server 2005中的Microsoft群集演算法對消費者做市場區隔。根據消費者對3G手機的功能需求分成三群：第一群為一般客戶群，第二群為目標客戶群，第三群為特定功能取向客戶群，再利用分群結果與基本資料做交叉分析，最後根據每一群的特性分別提出適當的行銷策略與建議。

El presente informe acopia la experiencia obtenida laborando dentro de la multinacional HUAWEI DEL PERU, en el área de implementación primero como ingeniero de campo y luego como ingeniero de proyecto para el proyecto 3G de Claro-Perú. Para llevar a cabo este proyecto, en la etapa de implementación, actualmente se requiere pasar por varias etapas que son: requerimiento de nuevo nodo B a instalar (solicitado por el cliente, CLARO DEL PERU), el estudio de campo (para ver el espacio disponible para los nuevos equipos), solicitud de materiales (al área logística), instalación de equipos, poner la instalación al aire y la aceptación de los equipos instalados; luego de esto se realiza el cobro por el servicio prestado. Con la experiencia de haber instalado más de 1000 nodos B siempre respetando el estándar de calidad de HUAWEI y solucionando cualquier problema o contratiempo que se dé al momento de la instalación o luego de ella, HUAWEI, como empresa, ha logrado tener no solo como cliente a CLARO si no trabajar con los otros dos grandes operadores (TELEFONICA DEL PERÚ y NEXTEL) dándole servicio de implementación, mantenimiento, de infraestructura de torre, etc. El presente informe describirá los aspectos tomados al momento de la implementación de un Nodo B.

Doctor of Philosophy (Ph.D.) / The buzzword of this decade has been convergence: the convergence of telecommunications, Internet, entertainment, and information technologies for the seamless provisioning of multimedia services across different network types. Thus the future Next Generation Mobile Network (NGMN) can be envisioned as a group of co-existing heterogeneous mobile data networking technologies sharing a common Internet Protocol (IP) based backbone. In such all-IP based heterogeneous networking environments, ongoing sessions from roaming users are subjected to frequent vertical handoffs across network boundaries. Therefore, ensuring uninterrupted service continuity during session handoffs requires successful mobility and session management mechanisms to be implemented in these participating access networks. Therefore, it is essential for a common interworking framework to be in place for ensuring seamless service continuity over dissimilar networks to enable a potential user to freely roam from one network to another. For the best of our knowledge, the need for a suitable unified mobility and session management framework for the NGMN has not been successfully addressed as yet. This can be seen as the primary motivation of this research. Therefore, the key objectives of this thesis can be stated as:  To propose a mobility-aware novel architecture for interworking between heterogeneous mobile data networks  To propose a framework for facilitating unified real-time session management (inclusive of session establishment and seamless session handoff) across these different networks. In order to achieve the above goals, an interworking architecture is designed by incorporating the IP Multimedia Subsystem (IMS) as the coupling mediator between dissipate mobile data networking technologies. Subsequently, two different mobility management frameworks are proposed and implemented over the initial interworking architectural design. The first mobility management framework is fully handled by the IMS at the Application Layer. This framework is primarily dependant on the IMS’s default session management protocol, which is the Session Initiation Protocol (SIP). The second framework is a combined method based on SIP and the Mobile IP (MIP) protocols, which is essentially operated at the Network Layer. An analytical model is derived for evaluating the proposed scheme for analyzing the network Quality of Service (QoS) metrics and measures involved in session mobility management for the proposed mobility management frameworks. More precisely, these analyzed QoS metrics include vertical handoff delay, transient packet loss, jitter, and signaling overhead/cost. The results of the QoS analysis indicates that a MIP-SIP based mobility management framework performs better than its predecessor, the Pure-SIP based mobility management method. Also, the analysis results indicate that the QoS performances for the investigated parameters are within acceptable levels for real-time VoIP conversations. An OPNET based simulation platform is also used for modeling the proposed mobility management frameworks. All simulated scenarios prove to be capable of performing successful VoIP session handoffs between dissimilar networks whilst maintaining acceptable QoS levels. Lastly, based on the findings, the contributions made by this thesis can be summarized as:  The development of a novel framework for interworked heterogeneous mobile data networks in a NGMN environment.  The final design conveniently enables 3G cellular technologies (such as the Universal Mobile Telecommunications Systems (UMTS) or Code Division Multiple Access 2000 (CDMA2000) type systems), Wireless Local Area Networking (WLAN) technologies, and Wireless Metropolitan Area Networking (WMAN) technologies (e.g., Broadband Wireless Access (BWA) systems such as WiMAX) to interwork under a common signaling platform.  The introduction of a novel unified/centralized mobility and session management platform by exploiting the IMS as a universal coupling mediator for real-time session negotiation and management.  This enables a roaming user to seamlessly handoff sessions between different heterogeneous networks.  As secondary outcomes of this thesis, an analytical framework and an OPNET simulation framework are developed for analyzing vertical handoff performance. This OPNET simulation platform is suitable for commercial use.

<p>Genom hela arbetet har enkelhet och användbarhet varit ledorden. Detta för att man ska kunna implementera tjänster för en relativt liten målgrupp utan att behöva göra större investeringar. I linje med detta har möjligheter för att kunna erbjuda tjänsten till en större målgrupp och därmed få ned kostnaden per användare eftersökts.</p><p>Rapporten börjar med en studie av 3G, WLAN och Bluetooth för att läsaren ska få en grund i de tekniker på vilka tjänsterna skulle kunna implementeras. Sedan diskuteras dagens tjänster och vilka önskemål om tjänster som framkommit från diskussioner med olika parter. Slutligen exemplifieras ett antal tjänster som skulle kunna tillämpas på dagens tekniker.</p><p>Efter att ha läst rapporten skall läsaren ha fått en uppfattning hur mobila tjänster med hög överföringshastighet bör utformas för att underlätta kommunikation för funktionshindrade.</p>

A recent surge in the usage of instant messaging (IM) applications on mobile devices has brought the energy efficiency of those applications into the light. We are entering an era where IM applications are changing the message communication on mobile devices, beginning to overtake SMS messages and even phone calls in some cases. Smartphones experience a tremendous increase of data transmissions through wireless interfaces. As illustrated in this work, today's IM applications differ vastly in energy consumption when using the third generation (3G) cellular communication. This thesis focuses on studying the 3G transmission energy footprint of IM applications at the handset level. The energy cost of a common feature used in IM applications that informs that the user is currently typing a response ('typing notify'), is evaluated. The feature is shown to incur a great increase in energy cost compared to the base chat function, ranging from an increase of 43 % to 117 %. The work also proposes a bundle technique that aggregates chat messages over time reducing the energy consumption at the cost of delay for the user. The results show that the bundle technique can save up to 47 % in energy consumption while still keeping the chat function. For the evaluation, conversations collected from a popular IM application are used.

Genom hela arbetet har enkelhet och användbarhet varit ledorden. Detta för att man ska kunna implementera tjänster för en relativt liten målgrupp utan att behöva göra större investeringar. I linje med detta har möjligheter för att kunna erbjuda tjänsten till en större målgrupp och därmed få ned kostnaden per användare eftersökts. Rapporten börjar med en studie av 3G, WLAN och Bluetooth för att läsaren ska få en grund i de tekniker på vilka tjänsterna skulle kunna implementeras. Sedan diskuteras dagens tjänster och vilka önskemål om tjänster som framkommit från diskussioner med olika parter. Slutligen exemplifieras ett antal tjänster som skulle kunna tillämpas på dagens tekniker. Efter att ha läst rapporten skall läsaren ha fått en uppfattning hur mobila tjänster med hög överföringshastighet bör utformas för att underlätta kommunikation för funktionshindrade.

Innovations of technologies often brings the industries impacts of different extents, if there is a company who holds KSF (key successful factor) in hand and becomes the leader, another would gradually lose his competitiveness because of not having KSF. This research looks at the development history of the Third Generation (3G) telecommunication services of Japan as background, which contains the overall environment, the 3G technology systems, the industry value-chain, the using condition of telecommunication services. Cooperating with the operation performance data including the number of 3G subscribers, ARPU (average revenue per user), the using amount of data services, the revenue of the 3G operators, etc., I probed into the KSF of the distribution of 3G, focused especially on why the performance of the early entrant NTT DoCoMo would fell behind the follower KDDI/au. And from the research results, I further discussed the market trend of the future 3G industry, hoping to provide references for the new incomers of 3G in Taiwan. As 3G services has only been started for less than 3 years and relevant academic researches remain few, this thesis can be seen as a exploratory research. And this research is based on literature survey of second-hand materials collected from white papers, fact sheets, media reports, proprietors¡¦ public materials, opinions from concerned professionals, industrial research reports, resources on the internet, etc., from which I analyzed and verified the operation performances of the operators and its relativity with the KSF I concluded from the literature: quality of telecommunications, speed of data transfer, provided contents and services, charge plans and promotion, properties and design of mobiles. The research show that what effect the performance of operators in the early period of 3G distribution are quality of telecommunications and the properties and series number of corresponding mobiles, and after the infrastructure construction period the focus would shift to new 3G services and contents and the price charged. As the telecommunication industry of Japan is on the way from infrastructure construction period to overall growth period, the performance of operators would be affected by the design and properties of corresponding mobiles and the telecommunication fees. Due to the 900i series mobile and the follow-up of the packet norm, the competitiveness of NTT DoCoMo on 3G has apparently raised. Although the number of 3G subscribers of KDDI/au still remains 3 times of DoCoMo, as DoCoMo holds 60% of the market, its top status of the telecommunication industry in Japan seems hard to be shattered. As there are still two important factors: the price battle of data telecommunication and the realization of number portability that may bring huge changes to the 3G market of Japan, the real battle of 3G can be seen as just unveiled.

SCTP (Stream Control Transmission Protocol) was proposed by IETF. It shows superior extensibility and compatibility as compared to other transport layer protocols, such as TCP and UDP. In addition, it supports multi-streaming and multi-homing. Although an SCTP connection can convey many video streams from different applications, it lacks the provision of different QoS for different streams in the same association. On the other hand, more and more mobile devices are equipped with multiple network (e.g., UMTS/WLAN) interfaces to transmit packets over 3G cellular networks or wireless local area networks. This thesis presents a dynamic chunk adjustment scheme for SCTP-based video streaming in an integrated UMTS and WLAN network. The proposed scheme can support QoS guarantees for different streams in an SCTP association whenever a mobile node moves across the two networks or remains service by either network. Besides, when a mobile node roams from a WLAN to a UMTS, the proposed ¡§deassociation¡¨ capability is applied to increase the channel utilization in 3G cellular networks. Performance evaluations on NS-2 are presented to demonstrate the effectiveness and the advantage of our proposed scheme over the original SCTP.

Multimedia streaming is one of the killer applications for cellular communications. Although the 3GPP proposes the Packet-Switched Streaming (PSS) protocol to support the multimedia streaming services, the performances are still not good enough. To improve the performances, most of the researches divide the cellular networks into two parts: the wired network and the wireless network, and focus on the wireless network part. Hence the adaptive streaming was proposed. It utilizes the RTCP feedback in RTP to monitor the wireless network, and makes appropriate transmission parameters adjustments to prevent from buffer underflow and packet loss. But the overall performance may not be only limited by the wireless network part. Also, with high mobility, the link quality may be influenced severely by many factors. Hence, we will evaluate the performance of streaming services over 3G cellular networks on the train of Taiwan high speed railway in this paper and propose a mechanism to improve the performance.