Download or read book Interference Analysis of and Dynamic Channel Assignment Algorithms in TD CDMA TDD Systems written by Harald Haas and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interference Analysis Of and Dynamic Channel Assignment Algorithms In TD CDMA written by Harald Haas and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The radio frequency spectrum for commercial wireless communications has become an expensive commodity. Consequently, radio access techniques are required which enable the efficient exploitation of these resources. This, however, is a difficult task due to an increasing diversity of wireless services. Hence, in order to achieve acceptable spectrum efficiency a flexible air- interface is required. It has been demonstrated that code division multiple access (CDMA) provides flexibility by enabling efficient multi user access in a cellular environment. In addition, time division duplex (TDD) as compared to frequency division duplex (FDD) represents an appropriate method to cater for the asymmetric use of a duplex channel. However, the TDD technique is subject to additional interference mechanisms in particular if neighbouring cells require different rates of asymmetry. If TDD is combined with an interference limited multiple access technique such as CDMA, the additional interference mechanism represents an important issue. This issue poses the question of whether a CDMA/TDD air-interface can be used in a cellular environment. The problems are eased if a hybrid TDMA (time division multiple access) / CDMA interface (TD-CDMA) is used. The reason for this is that the TDMA component adds another degree of freedom which can be utilised to avoid interference. This, however, requires special channel assignment techniques. This thesis analyses cellular CDMA/TDD systems used in indoor environments. A key parameter investigated is the interference in such systems. In the interference analysis a special focus is placed on adjacent channel interference since the jamming entity and victim entity can be in close proximity. The interference analysis shows that co-location of BS's using adjacent channels is not feasible for an adjacent channel protection factor that is less than 40 dB and frame synchronisation errors of more than 10%. Furthermore, it is demonstrated that ideal frame synchronisation does not necessarily yield the highest capacity. As a consequence, a new technique termed 'TS-opposing' is introduced. This method is intended to enable a cellular TD-CDMA/TDD system to apply cell independent channel asymmetry. For this purpose, a centralised DCA is developed. It is found that this algorithm indeed enables neighbouring cells to adopt different rates of asymmetry without a significant capacity loss. Moreover, a decentralised DCA algorithm based on the TS-opposing principle is developed. In this context, a novel TS assignment concept is proposed which reduces the complexity associated with the TS-opposing technique. In addition, the TS assignment plan allows for full spatial coverage. It is shown that the capacity of a TD-CDMA/TDD interface can be greater than the capacity of an equivalent FDD interface. The performance of the decentralised DCA algorithm is limited by the interference in the uplink. Therefore, additional methods which assist in reducing the interference in the uplink are envisaged to further improve the performance of the decentralised DCA algorithm. The exploitation of the TS-opposing technique in two different ways demonstrates that this method can be used to improve the performance of a TD-CDMA/TDD system significantly.
Download or read book Next Generation Mobile Access Technologies written by Harald Haas and published by Cambridge University Press. This book was released on 2008-01-10 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future generations of wireless networks will place great demands on the performance of radio access technology. This book describes the features of various mobile access technologies and assesses their strengths and weaknesses. In particular, it describes the underlying principles and practical implementation schemes for time division duplexing (TDD). The book begins with an overview of next-generation wireless systems. It then describes the basics of duplex communication modes, interference in cellular systems, and multiple user access techniques. Focusing on TDD systems, dynamic channel assignment algorithms are discussed, as are multi-hop communications schemes, radio resource management, interference cancellation, and smart antennas. Real-world examples from UMTS, wireless LAN, and Bluetooth systems are described. The book is aimed at all those involved in the design and implementation of wireless systems, as well as at graduate students and researchers working in the area of wireless communications. For more information visit www.cambridge.org/9781107407794.
Download or read book Intelligent Systems From Theory to Practice written by Vassil Sgurev and published by Springer. This book was released on 2010-09-23 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the modern science and technology there are some research directions and ch- lenges which are at the forefront of world wide research activities because of their relevance. This relevance may be related to different aspects. First, from a point of view of researchers it can be implied by just an analytic or algorithmic difficulty in the solution of problems within an area. From a broader perspective, this re- vance can be related to how important problems and challenges in a particular area are to society, corporate or national competitiveness, etc. Needless to say that the latter, more global challenges are probably more decisive a driving force for s- ence seen from a global perspective. One of such “meta-challenges” in the present world is that of intelligent s- tems. For a long time it has been obvious that the complexity of our world and the speed of changes we face in virtually all processes that have impact on our life imply a need to automate many tasks and processes that have been so far limited to human beings because they require some sort of intelligence.
Download or read book Advances in Data Mining Applications and Theoretical Aspects written by Petra Perner and published by Springer Science & Business Media. This book was released on 2009-07-09 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume comprises the proceedings of the Industrial Conference on Data Mining (ICDM 2009) held in Leipzig (www.data-mining-forum.de). For this edition the Program Committee received 130 submissions. After the pe- review process, we accepted 32 high-quality papers for oral presentation that are included in this book. The topics range from theoretical aspects of data mining to app- cations of data mining, such as on multimedia data, in marketing, finance and telec- munication, in medicine and agriculture, and in process control, industry and society. Ten papers were selected for poster presentations that are published in the ICDM Poster Proceedings Volume by ibai-publishing (www.ibai-publishing.org). In conjunction with ICDM two workshops were run focusing on special hot app- cation-oriented topics in data mining. The workshop Data Mining in Marketing DMM 2009 was run for the second time. The papers are published in a separate workshop book “Advances in Data Mining on Markting” by ibai-publishing (www.ibai-publishing.org). The Workshop on Case-Based Reasoning for Multimedia Data CBR-MD ran for the second year. The papers are published in a special issue of the International Journal of Transactios on Case-Based Reasoning (www.ibai-publishing.org/journal/cbr).
Download or read book Human Computer Interaction Towards Intelligent and Implicit Interaction written by Masaaki Kurosu and published by Springer. This book was released on 2013-07-01 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: The five-volume set LNCS 8004--8008 constitutes the refereed proceedings of the 15th International Conference on Human-Computer Interaction, HCII 2013, held in Las Vegas, NV, USA in July 2013. The total of 1666 papers and 303 posters presented at the HCII 2013 conferences was carefully reviewed and selected from 5210 submissions. These papers address the latest research and development efforts and highlight the human aspects of design and use of computing systems. The papers accepted for presentation thoroughly cover the entire field of human-computer interaction, addressing major advances in knowledge and effective use of computers in a variety of application areas. This volume contains papers in the thematic area of human-computer interaction, addressing the following major topics: adaptive, personalised and context-aware interaction; computational vision in HCI; emotions in HCI; biophysiological aspects of interaction.
Download or read book A Comprehensive Review of Methods for the Channel Allocation Problem written by Cheeneebash, Jayrani and published by African Minds. This book was released on 2014-12-01 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of the channel allocation problem has received much attention during the last decade. Several techniques such as genetic algorithm, artificial neural network, simulated annealing, tabu search and others have been used. This book is devoted to compiling all the techniques that have been used to solve the channel allocation problem. Each of the methods is described fully in a manner that explains the essential parts of how the techniques are formulated and applied in solving the problem. This textbook will be helpful to students studying communications or researchers as it compiles all the techniques used since this problem was first solved.
Download or read book Encyclopedia of Mobile Computing and Commerce written by Taniar, David and published by IGI Global. This book was released on 2007-04-30 with total page 1176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The "Encyclopedia of Mobile Computing and Commerce" presents current trends in mobile computing and their commercial applications. Hundreds of internationally renowned scholars and practitioners have written comprehensive articles exploring such topics as location and context awareness, mobile networks, mobile services, the socio impact of mobile technology, and mobile software engineering.
Download or read book Dynamic Channel Assignment written by Angel Lozano and published by LAP Lambert Academic Publishing. This book was released on 2009-11 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: The evolution of mobile wireless communication, triggered by an ever growing need for high capacity and new services, has fueled the interest in finding more efficient ways of managing the system resources. The most important of those resources are radio spectrum and power. Dynamic Channel Assignment (DCA) enables a more efficient use of the spectrum and eliminates the burden of frequency planning. In this monograph, we compare the performance of a number of distributed DCA schemes and propose a novel algorithm well suited to mobility environments. Power, in turn, is both a scarce resource at mobile devices and a constraining factor in systems inherently limited by interference. This has led to the development of a variety of power control (PC) schemes. We quantify the impact of mobility on the performance of PC as well as the degradation associated with imperfect signal and interference estimation. Despite the activity in both the DCA and PC arenas, little had been done to try to effectively integrate them. We investigate the integration of DCA and PC and create a family of integrated algorithms, fully distributed and adaptive, that deliver superior performance.
Download or read book 4g Mobile and Wireless Communications Technologies written by Sofoklis Kyriazakos and published by CRC Press. This book was released on 2022-09-01 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mobile and wireless communications are moving towards a new era that will be characterized by the seamless collaboration of heterogeneous systems, the need for high speed communications while on the move and for advanced services with quality guarantees. Recent market research studies show that most of the traffic in the future wireless networks will be produced by mobile multimedia services which are expected to proliferate by the year 2010. On the other hand mobile and wireless communications technology is becoming more and more important in developing countries where people demand fast deployment and low cost for broadband wireless internet services.The objective of this volume is to gather research and development on topics shaping the fourth generation (4G) in mobile and wireless communications and reveal the key trends and enabling technologies for 4G. We envisage 4G wireless communication systems as IP based solution providing integrated services (voice, data, multimedia) regardless of time and end-users? location. 4G technologies will manifest the benefits of the wireless and wired technologies convergence, through enabling a wide range of innovative (both indoor and outdoor) applications. 4G applications will feature premium quality, high security and an affordable cost. The vision, though fantastic, is associated with a host of technical and technological challenges.A great deal of the latter are discussed in the articles of this volume, which aims at providing insights on the research issues and solutions that are directly associated with leading edge 4G technologies and services.Taking into account recent developments in the world of wireless communications we have given emphasis to cover all these technologies and aspects that are considered as cornerstones for achieving the goals set for 4G and that will further boost research and development of next-generation mobile communications.
Download or read book Conference Record written by and published by . This book was released on 1991 with total page 1078 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 2004 with total page 1032 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theses on any subject submitted by the academic libraries in the UK and Ireland.
Download or read book Channel allocation comparative analysis for tdma technology written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Os esquemas de alocação fixa de canais - FCA - conferem aos Sistemas de Comunicação Móveis Celulares estabilidade com o custo da necessidade de um pré-planejamento de freqüências, trazendo como conseqüência a baixa tolerância à variabilidade de tráfego. Algoritmos de alocação dinâmica de canais - DCA - tem sido propostos por diversos autores com o intuito de minimizar estes problemas, permitindo ao sistema flexibilidade no momento da escolha do canal candidato para servir a uma ligação. Esquemas de alocação híbrida de canais - HCA, combinam as técnicas de alocação fixa com alocação dinâmica de canais, conferindo ao mesmo tempo estabilidade e flexibilidade ao sistema. Este trabalho compara os algoritmos FCA, DCA e HCA sobre um mesmo cenário de simulação, permitindo analisar o desempenho dos mesmos. O esquema FCA utilizado é o mais simples, onde o primeiro canal com o nível aceitável de relação sinal interferência é escolhido para ser alocado. O esquema DCA utiliza a técnica de Segregação de Canais - CS, permitindo ao sistema maior flexibilidade no momento da escolha do canal candidato, devido a não existência do pré-planejamento de freqüências. O terceiro algoritmo, HCA, combina os dois esquemas anteriores. Ao final, será analisado o impacto de se priorizar o procedimento de handoff utilizando-se a técnica conhecida como Canais de Guarda.
Download or read book Proceedings written by and published by . This book was released on 2003 with total page 1232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Algorithms for Dynamic Channel Assignment written by Robert T. Harrild and published by . This book was released on 1986 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The IEEE International Symposium on Personal Indoor and Mobile Radio Communications written by IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications and published by . This book was released on 2001 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
