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This book has both theoretical and practical aspects. It is intended to provide the reader with a deeper understanding of the concepts of OFDM and CDMA. Thus, the theoretical basics are analyzed and presented in some detail. Both of the concepts are widely applied in practice. Therefore, a considerable part of the book is devoted to system design and implementation aspects and to the presentation of existing communication systems.
The book is organized as follows. In Chapter 1, we give a brief overview of the basic
principles of digital communications and introduce our notation. We represent signals as vectors, which often leads to a straightforward geometrical visualization of many seemingly abstract mathematical facts. The concept of orthogonality between signal vectors is a key to the understanding of OFDM and CDMA, and the Euclidean distance between signal vectors is an important concept to analyze the performance of a digital transmission system.Wireless communication systems often have to cope with severe multipath fading in a mobile radio channel. Chapter 2 treats these aspects. First, the physical situation of multipath propagation is analyzed and statistical models of the mobile radio channel are presented.Then, the problems of digital transmission over these channels are discussed and the basic principles of Chapter 1 are extended for those channels. Digital wireless communication over fading channels is hardly possible without using some kind of error protection or channel coding. Chapter 3 gives a brief overview of the most important channel coding techniques that are used in the above-mentioned communication systems. Convolutional codes are typically used in these systems, and many of the systems have very closely related (or even identical) channel coding options. Thus, the major part of Chapter 3 is dedicated to convolutional codes as they are applied in these systems. A short presentation of Reed–Solomon Codes is also included because they are used as outer codes in the DVBT system, together with inner convolutional codes. Chapter 4 is devoted to OFDM. First, the underlying ideas and the basic principles are explained by using the basic principles presented in Chapter 1. Then implementation aspects are discussed as well as channel estimation and synchronization aspects that are relevant for the above-mentioned systems.All these systems are designed for mobile radio channels and use channel coding. therefore,we give a comprehensive discussion of system design aspects and how to fit all these things together in an optimal way for a given channel. Last but not least, the transmission schemes for DAB, DVB-T and WLAN systems are presented and discussed. Chapter 5 is devoted to CDMA, focusing on its main application area – mobile communications. This application area requires not only sophisticated digital transmission techniques and receiver structures but also some additional methods as, for example, a soft handover, a fast and exact power control mechanism as well as some special planning techniques to achieve an acceptable radio network performance. Therefore, the first section of Chapter 5 discusses these methods and some general principles of CDMA and mobile radio networks. CDMA receivers may be simple or quite sophisticated, thereby making use of knowledge about other users. These theoretically involved topics are treated in the following three subsections. As examples of CDMA applications we discuss the most important systems already mentioned, namely, GPS, cdmaOne (IS-95), cdma2000 and UMTS with its two
transmission modes called Wideband CDMA and Time Division CDMA. Furthermore,
Wireless LAN systems conforming to the standard IEEE 802.11 are also included in this
section as some transmission modes of these systems are based on spreading.
【文件名】:0636@52RD_Wiley.Theory.and.Applications.of.OFDM.and.CDMA.Wideband.Wireless.Communications.part1.rar
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