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Yayın Cooperative strategies, achievable rates and resource allocation for OFDMA channels(Işık Üniversitesi, 2011-07-28) Bakım, İsmail Sezi; Kaya, Onur; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Doktora ProgramıThe design of next generation wireless communication systems brings along new challenges, since the degrading factors such as fading and multi-user interference become harder to deal with as the number of users and the bandwidth require- ments increase. Orthogonal Frequency Division Multiple Access (OFDMA) is a multiple accessing technique which provides a solution to both of the problems above: it provides a relatively simple way of assigning available bandwidth to users, while avoiding interference; and at the same time, it converts a frequency selective fading channel, to parallel flat fading subchannels, hence reducing the effects of intersymbol interference. However, in wireless channels, what is tradi- tionally considered as interference is in fact side information, and combined with the diversity created by the orthogonal subchannels in OFDMA, this side infor»mation can be carefully taken advantage of to increase the rates achievable by the users. In our thesis, without imposing any prior constraints on subchannel allocation, we investigate cooperation strategies, achievable rates and resource allocation for OFDMA channels. We propose new cooperative encoding strategies for wireless communication net- works över OFDMA channels. We particularly focus on a two user cooperative OFDMA system, based on block Markov superposition encoding (BMSE). We obtain expressions of the resulting achievable rate regions for ali proposed coroperative encoding strategies. We show that, by allowing for re-partitioning and re-encoding of the cooperative messages across subchannels, it is possible to better exploit the diversity created by OFDMA, and higher rates can be achieved. In order to take full advantage of the diversity created by OFDMA, we then introduce a channel adaptive cooperation strategy for OFDMA, and optimize the transmit powers as a function of the channel states. We provide the optimality conditions that need to be satisfied by the powers associated with the users' codewords and derive the closed form expressions for the optimal powers.Yayın SMS distribution and information system(Işık Üniversitesi, 2003-07) Yüzücü, Haluk; Yarman, Bekir Sıddık Binboğa; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Bilgisayar Mühendisliği Yüksek Lisans ProgramıIn this master's thesis, a web based application software package is developed using a mobile terminal (Siemens M20), for sending SMS message to individuals or groups to disseminate information to cellular-phones. Employing utilizing the S/W developed in this thesis, SMS messages are sent to cell-phones via internet and users will get information using their cell-phone (Eg: for attendance, exam results, seminar days, etc..). Microsoft SQL Server Database is used for storing the user information, incoming and outgoing messages. ASP (Active Server Page) programming language is utilized for web based interface coding. The application software is developed on Siemens M20 mobile terminal device. Mobile communication has become an indispensable parts of everyone's daily life. This project, which has been developed by using SMS service, a branch of mobile communication, aims to enable people to access information with their cell-phones, when there is no internet. With this package institutions will be able to send announcements to groups of individuals as short messages at the same time. Besides these, with the developed web interface, SMS message will be sent only through cell-phones, but through internet as well.Yayın A mobile worker management system for a logistics company(Işık Üniversitesi, 2005-10) Güven, Uğur; Kuru, Selahattin; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Bilgisayar Mühendisliği Yüksek Lisans ProgramıMobile worker management system is an application which aims to manage a company's site workers whose staff is on a specific area. The goal of the system is to assign daily tasks, receive completed tasks and in formations, inform workers about task changes, and send new tasks to the workers. Mobile Workers send their completed/updated tasks, and GPS positions, which is received from Bluetooth GPS receiver, to Server-Side application, which is stored in company center by using Client-Side Mobile Application on PDA devices at predefined times over GPRS Connection. Server-Side Application receives new/updated/completed tasks, makes assignments and changes and sends them to the mobile workers. The application makes all assignments and needed updates automatically by using application parameters.Yayın Performance analysis of space time transmit diversity in UMTS under presence of carrier phase offset(Işık Üniversitesi, 2003-12) Toplu, Mehmet İlker; Panayırcı, Erdal; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıThe reguirements for the next generation of mobile communication systems are primarily driven by the explosive growth of worldwide mobile communication subscribers. Additionaly, 3G systems will allow various of new services including wireless Internet acess, high -speed mobile data services and other multimedia applications. The expected growth of subscibers and the provided services indicate the need for increased system capacity of the future mobile communication systems. This thesis deals with Transmit Diversity techniques used for capacity enhancement in the downlink. The principle of Transmit Diversity is to send the same information with two antennas at the base station. If the signals from the different antennas fade independently, diversity at the receiver is achieved. Therefore, the ratio between the desired signal and the noise plus interference from other base stations can be enhanced. This means that there is less transmission power required to meet the same signal quality as in the single antenna case. The investigations within the scope of this work focus on Space-Time Transmit Diversity concept specified in the UMTS standard. I consider the application of Alamouti's Space-Time Transmit Diversity tevhniques in different scenarios. It's performance is evaluated by the calculation of the Average Error at the receiver depentent on the Signal to Noise Ratio. The performance of this method is compared by means MATLAB simulations.Yayın Implementation of a fixed cellular terminal with mobile phone(Işık Üniversitesi, 2002-09) Tekeş, Coşkun; Yarman, Bekir Sıddık Binboğa; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans ProgramıThe thesis reports the design and realization of a fixed cellular terminal (FCT) device which works with a mobile phone as a GSM Module. The design is emphasized at the structure not to be complex and suitable to be used in mass production. Before starting our design, our currently available FCT products and their functional properties are studied and the most important and usefull properties are fixed. This design is not only a theorical project, it is also realized as a mass product and take part in the market as a product.Yayın An evaluation of consumer intention to participate in mobile advertising and an empirical study conducted in İstanbul(Işık Üniversitesi, 2007) Yücel, Yasemin; Ferman, Ali Murat; Işık Üniversitesi, Sosyal Bilimler Enstitüsü, Çağdaş İşletme Yönetimi Doktora ProgramıMobile services provide companies with a strong marketing potential, because mobile technologies enable brands to have a direct communication with consumers, regardless of time and place. Therefore, mobile marketing brings about a variety of opportunities for marketers. New digital marketing channels like Internet and mobile telephony lead to interactive and personalized content and context in marketing messages so, considering marketing communications, these channels offer a unique opportunity to reach consumers. High market penetration of mobile phones and the emergence of high speed mobile network technologies have attracted advertising industry and using of mobile medium as a marketing communication tool has been increasing. Marketing communications were highly influenced by recent developments in technology and the gradual transformation from mass marketing to targeted marketing. Besides the Internet, mobile medium presents important advertising opportunities Mobile marketing has been an issue of interest for both academics and practitioners. Moreover, the number of companies investing in mobile marketing campaigns is increasing. However, in spite of the increasing attention from both academics and practitioners, there is little academic research conducted on this topic and yet, the nature and implications of the mobile channel are not fully understood. Considering the potential of mobile media, it is interesting to understand the relation between consumer's attitude towards mobile marketing and mobile marketing efforts In this context, this research aims to help understanding this relation and it examines the factors which affect the acceptance of mobile advertising from consumers' perspective. Mobile marketing stands for the use of SMS, MMS, client applications and other interactive multimedia methods as being marketing media in both pull and push type campaigns. Because of insufficient definitions of mobile advertising and mobile marketing terms create ambiguity in literature and, various terms seem to refer to the same phenomenon, it is important to highlight that above mentioned type of activities are investigated under the scope of mobile advertising campaigns in this study. The study aims to investigate the appreciation of mobile advertising by consumers. Besides, another intention of the research is to cues about mobile marketing, positioning with mobile advertising, evaluation of the concepts, potentials, boundaries and finally the critical success factors from the customer acceptance point of view. This study makes two contributions to the literature: Firstly, assessing previous studies in the field, the study proposes a conceptual research model of consumer intention to join mobile advertising campaigns. The literature was surveyed to provide a benchmark for better understanding the phenomena and deriving the theoretical framework for the proposed research in Chapter 1 and Chapter 2. Secondly, the model is tested by empirical data obtained from Turkish mobile market. Mobile market in Turkey has experienced 60% mobile phone penetration; three active mobile operators with around 250 service provider partners operate in the market and population is predominantly young in Turkey. Additionally, 3G (3rd Generation) network licenses tender that is planned to be hold on 7th of September; 2007 will allow 5 operators who will serve wide band services including advanced mobile advertising campaigns. These facts imply that Turkish mobile market has a huge potential for mobile marketing activities and mobile advertising campaigns. A model of consumer intention to participate in mobile advertising is developed in the Chapter 3 of this study, along with a number of associated hypotheses and Chapter 3 also includes the testing of the model and findings are presented, with managerial implications and suggestions for future studies. Conclusions are provided in Chapter 4. The results of the study will provide various managerial insights to enlighten both contemporary and future cases of mobile advertising medium as an emerging one-to-one marketing channel. Findings give insights about influential factors on customer intention to participate in mobile advertising campaigns. The results might be helpful for those who take part in Turkish mobile advertising value chain, such as mobile marketing agencies, mobile marketing advertisers, mobile operators, and service providers etc. in clearly understanding antecedents of successful mobile advertising campaigns. This study will be beneficial for brands willing to be more active in direct marketing and mobile operators who are actively involved in mobile marketing campaigns, in understanding the degree of consumer response to mobile marketing campaigns and in determination of campaign types which are more desirable for consumers to participate.
