Khaled Fazel – författare

The technological progress in multi-carrier (MC) modulation led orthogonal frequency division multiplexing (OFDM) to become an important part of beyond 3G cellular mobile communication standards, including LTE and WiMAX. In addition, the flexibility offered by the spread spectrum (SS) and time division multiplexing (TDM) techniques motivated many researchers to investigate several MC combined multiple access schemes, such as MC-CDMA, OFDMA and MC-TDMA. These schemes benefit from the advantages of each sub-system and offer high flexibility, high spectral efficiency, simple detection strategies and narrow-band interference rejection capability. Multi-Carrier and Spread Spectrum Systems is one of the first books to describe and analyze the basic concepts of multi-carrier OFDM transmission and its combination with spread spectrum (MC-CDMA). The different architectures and detection strategies as well as baseband-related transceiver components are explained. This includes topics like FEC channel coding and decoding, modulation and demodulation (IFFT/FFT), digital I/Q-generation, time and frequency synchronisation, channel estimation, frequency domain equalization and RF aspects such as phase noise and non-linearity issues. Concrete examples of its applications for cellular mobile communication systems (B3G/4G) are given. Further derivatives of MC-SS (such as OFDMA, SS-MC-MA and DFT-spread OFDM) and their corresponding applications in the LTE, WiMAX, WLAN and DVB-RCT standards are detailed. Capacity and flexibility enhancements of multi-carrier OFDM systems by different MIMO diversity techniques such as space time/frequency coding (STC, SFC) and software defined radio concepts are also described.Written in a highly accessible manner this book provides a unique reference on the topics of multi-carrier and spread spectrum communications, assisting 4G engineers with their implementation. Fully updated new edition of successful text, including two new chapters on LTE and WiMAX Describes in detail new applications of OFDM in mobile communication standards Examines all multi-carrier spread spectrum schemes, with in-depth analysis, from theory to practice Introduces the essentials of important wireless standards based on multi-carrier/spread spectrum techniques.

Stefan Kaiser Khaled Fazel Radio System Design German Aerospace Center (DLR) Marconi Communications lnstitute of Communications and Navigation D-71522 Backnang, Germany D-82234 Wessling, Germany We are currently observing that frequency spectrum is a limited and valuable resource for wireless mobile communications. A good example can be observed among European network operators for the prices to pay for frequency bands for UMTS/IMT2000. Keeping this in mind, the fIrst goal when designing future wireless communication systems has to be the increase in spectral effIciency by allowing higher flexibility for the system design and deployment. The development in digital communications in the past years has enabled effIcient modulation and coding techniques for robust and spectral effIcient data, speech, audio and video transmission. Here, we should mention two interesting and successful techniques. These are the multi-carrier modulation (e. g. OFDM) and the spread spectrum technique (e. g. DS-CDMA). During the last decade of this millennium the technique of multi-carrier transmission for wireless broadband multimedia applications has received wide interest. Its fIrst great success was in 1990 as it was selected for the European Digital Audio Broadcasting (DAB) standard. Its further prominent success was in 1995 and 1998 as it was selected as modulation scheme for the European Digital Video Broadcasting (DVB-T) standard and in three broadband wireless indoor standards, namely European ETSI-HIPERLAN/2, American IEEE-802. 11a and Japanese MMAC, respectively.

The benefits and success of multi-carrier (MC) modulation on one hand, and the flexibility offered by spread spectrum (SS) techniques on the other, have, since 1993, motivated many researchers to investigate the combination of both techniques, known as multi-carrier spread-spectrum (MC-SS). This combination benefits from the main advantages of both systems and offers high flexibility, high spectral efficiency, simple detection strategies, narrow-band interference rejection capability, and so on. The basic principle of this combination is straightforward: the spreading is performed as direct sequence SS (DS-SS) but instead of transmitting the chips over a single carrier, several sub-carriers can be employed. The MC modulation and demodulation can easily be done in the digital domain by performing IFFT and FFT operations. The separation of the users' signals can be performed in the code domain. This means that the MC-SS system performs the spreading in the frequency domain, which allows for simple signal detection strategies. Since 1993, MC-SS has been extensively researched and new alternative solutions have been proposed.Meanwhile, deep system analyses and comparisons with DS-CDMA have been performed that show the superiority of MC-CDMA. This text, which consists of seven parts, contains a collection of papers, dealing with all aspects of MC-SS, presented at the Second International Workshop on Multi-Carrier Spread-Spectrum (MC-SS) and Related Topics, held from September 15-17, 1999 in Oberpfaffenhofen, Germany. It should be of value as a reference for researchers and practitioners working in the area of wireless communications and networks.

To operate future generation multimedia communications systems, high data rate transmission needs to be guaranteed with a high quality of service. For instance, the third generation cellular mobile systems should offer a high data rate up to two Mbit/s for video, audio, speech and data transmission. The important challenge for these cellular systems will be the choice of an appropriate multiple access scheme. The advantages of the spread spectrum technique are: high immunity against multipath distortion, no need for frequency planning, high flexibility and easier variable rate transmission. On the other hand, the technique of multi-carrier transmission has recently been receiving wide interest for high data rate applications. The advantages of multi-carrier transmission are the robustness in the case of frequency selective fading channels, in particular the reduced signal processing complexity by equalization in the frequency domain, and in the capability of narrow-band interference rejection.The advantages and success of multi-carrier (MC) modulation and the spread spectrum (SS) technique has led to the combination of MCM with SS, known as multi-carrier spread-spectrum (MC-SS) for cellular systems. This combination, benefits from the advantages of both schemes: higher flexibility, higher spectral efficiency, simpler detection techniques, and narrow band interference rejection capability. This volume contains a collection of papers which provide an overview of this emerging multiple access scheme. It should be of interest to researchers and practitioners working in the area of wireless communications and networking.

The key of a successful approach to the complex issue of designing wireless terminals for present and future communication systems (usually addressed to as '3rd Generation and beyond') lies in a single 'magic' word: multidisciplinarity. This was actually the philosophy which inspired and drove a fruitful teamwork performed at the University of Pisa (Italy) under the auspices of the European Space Agency (ESA) with the goal of developing a digital receiver for CDMA mobile communications. The most challenging issue of the project was the implementation into a single ASIC device of an advanced detector for multi-user CDMA signals featuring interference mitigation capability. The whole design process, starting from system specifications down to final hardware testing, required quite a demanding and synergic effort, involving telecom engineers on one side and electronic designers on the other. The development and the achievements of the project gave the authors the cue for writing this book whose contents represents the lesson learnt from such an interdisciplinary research activity. An Experimental Approach to CDMA and Interference Mitigation was written with the admittedly ambitious in

Khaled Fazel Stefan Kaiser Radio System Design DoCoMo Euro-Labs Marconi Communications Landsberger Strasse 312 D-71522 Backnang, Germany D-80687 Munich, Germany The field of multi-carrier and spread spectrum communications has became an important research topic with increasing number of research activities [1]. Especially in the last two years, beside deep system analysis of various multiple access schemes, new standardization activities in the framework of beyond 3G (B3G) concepts have been initiated. Multi-carrier transmission is considered to be a potential candidate to fulfil the requirements of the next generation system. The two important requirements of B3G/4G can be summarized as: i) much higher data rate for cellular mobile radio and ii) a unique physical layer specification for indoor/hot spot and outdoor/cellular applications, including fixed wireless access (FWA) schemes. The activities within the 3GPP and WiMAX fora are examples of such trends (see Fig. 1). IEEE 802 ETSI WAN UMTS, EDGE 3GPP (GSM) HiperMAN & IEEE 802. 16 WiMAX MAN HiperAccess WirelessMAN HiperLAN/2 IEEE 802. 11 LAN WiFi RLAN WirelessLAN IEEE 802.15 PAN Bluetooth BRAN Figure 1 Beyond 3G: Worldwide Standardization Activities xii Editorial Introduction The WiMAX (Worldwide Interoperability for Microwave Access [2]) vision is to provide broadband wireless access with its primary goal to promote IEEE 802. 16a-e and ETSI-BRAN standards through interoperability testing and certification. In the first step the broadband access to the so-called last mile applications with fixed positioned terminals is envisaged.

at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) in the year 1993, multi-carrier spread spectrum (MC-SS) has rapidly become one of the most wide spread independent research topics on the field of mobile radio communications.

Stefan Kaiser Khaled Fazel Radio System Design German Aerospace Center (DLR) Marconi Communications lnstitute of Communications and Navigation D-71522 Backnang, Germany D-82234 Wessling, Germany We are currently observing that frequency spectrum is a limited and valuable resource for wireless mobile communications. A good example can be observed among European network operators for the prices to pay for frequency bands for UMTS/IMT2000. Keeping this in mind, the fIrst goal when designing future wireless communication systems has to be the increase in spectral effIciency by allowing higher flexibility for the system design and deployment. The development in digital communications in the past years has enabled effIcient modulation and coding techniques for robust and spectral effIcient data, speech, audio and video transmission. Here, we should mention two interesting and successful techniques. These are the multi-carrier modulation (e. g. OFDM) and the spread spectrum technique (e. g. DS-CDMA). During the last decade of this millennium the technique of multi-carrier transmission for wireless broadband multimedia applications has received wide interest. Its fIrst great success was in 1990 as it was selected for the European Digital Audio Broadcasting (DAB) standard. Its further prominent success was in 1995 and 1998 as it was selected as modulation scheme for the European Digital Video Broadcasting (DVB-T) standard and in three broadband wireless indoor standards, namely European ETSI-HIPERLAN/2, American IEEE-802. 11a and Japanese MMAC, respectively.

Khaled Fazel Stefan Kaiser Digital Microwave Systems German Aerospace Center (DLR) Bosch Telecom GmbH Institute for Communications Technology D-71522 Backnang, Germany D-82234 Wessling, Germany In this last decade of this millennium the technique of multi-carrier transmission for wireless broadband multimedia applications has been receiving wide interests. Its first great success was in 1990 as it was selected in the European Digital Audio Broadcasting (DAB) standard. Its further prominent successes were in 1995 and 1998 as it was selected as modulation scheme in the European Digital Video Broadcasting (DVB-T) and in three broadband wireless indoor standards, namely ETSI-Hiperlan-II, American IEEE-802. 11 and Japanese MMAC, respectively. The benefits and success of multi-carrier (MC) modulation in one side and the flexibility offered by spread spectrum (SS) technique in other hand motivated many researchers to investigate the combination of both techniques, known as multi-carrier spread-spectrum (MC-SS). This combination benefits from the main advantages of both systems and offers high flexibility, high spectral efficiency, simple detection strategies, narrow­ band interference rejection capability, etc. . The basic principle of this combination is straightforward: The spreading is performed as direct SS (DS-SS) but instead of transmitting the chips over a single sequence carrier, several sub-carriers could be employed. As depicted in Figure 1, after spreading with assigned user specific code of processing gain G the frequency mapping and multi-carrier modulation is applied. In the receiver side after multi-carrier demodulation and frequency de-mapping, the corresponding detection algorithm will be performed.

l 1 Khaled Fazel , Gerhard P. Fettweis lGerman Aerospace Research Establishment (DLR) Institute for Communications Technology 0-82234 Oberpfaffenhofen, Germany lDresden University of Technology Department of Electrical Engineering 0-01062 Dresden, Germany To operate future generation multimedia communications systems high data rate transmission needs to be guaranteed with a high quality of service. For instance, the third generation cellular mobile systems should offer a high data rate up to 2 Mbitls for video, audio, speech and data transmission [1]. In addition, the important challenge for these cellular systems will be the choice of an appropriate multiple access scheme. These trends motivated many researchers to look for multiple access systems that offer high spectral efficiency. The technique of spread spectrum originating from the military applications may allow partly to fulfill the above requirements. Advantages of spread spectrum technique are broadly known: High immunity against multipath distortion, no need for frequency planning, high flexibility, easier variable rate transmission etc. [1-2]. A multiple access scheme based on direct sequence spread spectrum, known as direct sequence code division multiple access (DS-CDMA) relies on spreading the data stream using an assigned spreading code for each user in the time domain. The capability of minimising multiple access interference (MAl) is given by the cross­ correlation properties of spreading codes. In the case of multipath propagation the capability of distinguishing one component from others in the composite received signal is offered by the auto-correlation properties of the spreading codes [2].

Since the principle of multi-carrier code division multiple access (MC-CDMA) was simultaneously proposed by Khaled Fazel et al. and Nathan Yee et al: at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) in the year 1993, multi-carrier spread spectrum has rapidly become one of the most wide spread independent research topics on the ?eld of mobile radio communications. Therefore, the International Workshop on Multi-Carrier Spread Spectrum (MC-SS) was initiated in the year 1997 and renamed to the International Workshop on Multi-Carrier Systems & Solutions in 2009. The wireless standards 3GPP Long Term Evolution (LTE), WiMAX, IEEE 802.11a/n, and DxB have in common that they apply the spectrally ef?cient mul- carrier modulation in order to achieve very high rate data transmission. This trend is expected to continue in the future with the development of the next gene- tion of mobile wireless communications under the IMT-Advanced standardization activities. Additional measures like advanced coding, spreading, and MIMO are combined with multi-carrier transmission to further enhance the ef?ciency of future systems.The material summarized in this volume was selected for the seventh Int- national Workshop on Multi-Carrier Systems & Solutions (MC-SS 2009) held in Herrsching, Germany from 05-06 May 2009. The workshop was organized by the Institute of Communications and Navigation of the German Aerospace Center (DLR) in Oberpfaffenhofen, Germany.

The benefits and success of multi-carrier (MC) modulation on one side and the flexibility offered by the spread spectrum (SS) technique on the other side have motivated many researchers to investigate the combination of both techniques since 1993. This combination known as multi-carrier spread spectrum (MC-SS) benefits from the advantages of both systems and offers high flexibility, high spectral efficiency, simple detection strategies, narrow-band interference rejection capability, etc. The basic principle of this combination is straightforward: The spreading is performed as direct sequence spread spectrum (DS-SS) but instead of transmitting the chips over a single carrier, several sub-carriers are employed. The MC modulation and demodulation can easily be realized in the digital domain by performing IFFT and FFT operations. The separation of the users' signals can be performed in the code domain. MC-SS systems can perform the spreading in frequency direction, which allows for simple signal detection strategies. Since 1993, MC-SS has been deeply studied and new alternative solutions have been proposed. Meanwhile, deep system analysis and comparison with DS-CDMA have been performed that show the superiority of MC-CDMA.

Since the principle of multi-carrier code division multiple access (MC-CDMA) was simultaneously proposed by Khaled Fazel et al. and Nathan Yee et al. at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) in the year 1993, multi-carrier spread spectrum (MC-SS) has rapidly become one of the most wide spread independent research topics on the field of mobile radio communications. Therefore, the International Workshop on Multi-Carrier Spread Spectrum (MC-SS) was initiated in the year 1997. Multi-carrier and spread spectrum systems with their generic air interface and adaptive technologies are considered as potential candidates to fulfill the requirements of next generation mobile communications systems. The material summarized in this volume was selected for the 6th International Workshop on Multi-Carrier Spread Spectrum (MC-SS 2007) held in Herrsching, Germany from 07-09 May 2007. The workshop was organized by the Institute of Communications and Navigation of the German Aerospace Center (DLR) in Oberpfaffenhofen, Germany. During the workshop, many hot topics in the field of MC-SS were covered. First, several presentations regarding General Issues were given. Iterative Decoding strategies were also discussed. Furthermore, a special session was addressed on Interleave Multiple Division Access (IDMA). In the areas of Spectrum and Interference, Data Transmission, Adaptive Transmission, Multiple Antennas, Multi-Cell and Multi-Link, and Synchronization and Tracking new and innovative algorithms, strategies, and systems were proposed. Finally, a dominant hot topic during this workshop was the problem of Channel Estimation.

Since the principle of multi-carrier code division multiple access (MC-CDMA) was simultaneously proposed by Khaled Fazel et al. and Nathan Yee et al: at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) in the year 1993, multi-carrier spread spectrum has rapidly become one of the most wide spread independent research topics on the ?eld of mobile radio communications. Therefore, the International Workshop on Multi-Carrier Spread Spectrum (MC-SS) was initiated in the year 1997 and renamed to the International Workshop on Multi-Carrier Systems & Solutions in 2009. The wireless standards 3GPP Long Term Evolution (LTE), WiMAX, IEEE 802.11a/n, and DxB have in common that they apply the spectrally ef?cient mul- carrier modulation in order to achieve very high rate data transmission. This trend is expected to continue in the future with the development of the next gene- tion of mobile wireless communications under the IMT-Advanced standardization activities. Additional measures like advanced coding, spreading, and MIMO are combined with multi-carrier transmission to further enhance the ef?ciency of future systems.The material summarized in this volume was selected for the seventh Int- national Workshop on Multi-Carrier Systems & Solutions (MC-SS 2009) held in Herrsching, Germany from 05-06 May 2009. The workshop was organized by the Institute of Communications and Navigation of the German Aerospace Center (DLR) in Oberpfaffenhofen, Germany.