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1.5 Outline of This Textbook

This book is organized to allow the engineering practitioner, researcher, or student to rapidly find useful information on specific topics that are central to the infant world of mmWave wireless communications, including the nascent but commercially viable world of 60 GHz communication. Each chapter begins with an introduction that previews the material in each section and is completed with a summary that reviews salient points of each topic discussed. Chapter 1 serves as an introduction to the entire book, and motivates the study of mmWave communication.

Chapter 2 provides background material for wireless communication system design. This chapter begins with an introduction to the complex baseband signal representation and its relationship to the wireless medium that provides the physical channel for communication. Then, using the complex baseband model, the design of discrete-time wireless communication systems to send and receive information through the transmission of data symbols is discussed. This includes a summary of equalization concepts to deal with channel distortion effects and error-correcting codes to deal with degradations due to impairments in the channel and communication hardware. A special section is included on Orthogonal Frequency Division Multiplexing (OFDM) modulation, which is popular in many commercial standards such as 4G LTE and IEEE 802.11n. Finally, Chapter 2 concludes with implementation topics including the estimation and detection of signals at the receiver, the architecture used for RF/analog/digital circuits in a communication system, and the layering of a communication system.

Chapter 3 transitions into the fundamentals of mmWave propagation and summarizes the physical characteristics of the wireless channel at operating frequencies around 60 GHz and other mmWave frequencies. This chapter consists of several different aspects of the wireless channel, each of which builds a complete picture of a mmWave wireless channel model. New results for the 28, 38, and 73 GHz outdoor urban cellular environments are given in this chapter, and they demonstrate the improvements that adaptive antennas can make in both link budget and reduction of multipath delay spread. First, measurement results that characterize the large-scale path loss are summarized. Then the penetration/reflection ability of mmWave signals is reviewed, which will be important to determine the feasibility of NLOS communication. A special section is devoted to the loss experienced by mmWave signals due to atmospheric effects such as energy absorption of oxygen and water molecules. Ray tracing is also described, as this approach will be critical for accurate site selection and deployment of future mmWave systems, where both indoor and outdoor channel conditions are considered. Finally, the indoor and outdoor mmWave channels are summarized in terms of their temporal, spectral, and spatial characteristics with respect to realistic mobility scenarios.

Chapter 4 provides background on antenna theory with an emphasis on techniques that are relevant for mmWave communication: in-package and on-chip antennas. The high cable losses at mmWave frequencies motivate pushing the antennas as close to the signal processing as possible. An in-package integrated antenna is one that is manufactured as part of the packaging process whereas an on-chip antenna is one that is built as part of the semiconductor process. Cost savings can potentially be realized with on-chip antennas if research can provide designs of high efficiency. Potential antenna topologies for mmWave are reviewed including planar, lens, aperture, and array antennas. Although many classic textbooks have dealt with the important area of antennas, we focus on the key concepts that are vital for on-chip and in-package antennas that will be used in mmWave consumer electronic products in the future. Also, array theory and fundamental semiconductor properties are treated, so readers can understand the challenges and approaches for implementing on-chip antennas. Although these approaches are nascent, and far from perfected at the time of this writing, future integrated wireless devices operating in the 30-300 GHz range will likely rely on tight integration not used at conventional UHF microwave bands. The chapter concludes with a survey of classical results on array processing, which are relevant for mmWave using adaptive antenna arrays.

Chapter 5 describes semiconductor device basics and enumerates the hardware design challenges at mmWave carrier frequencies. This includes a discussion of the RF hardware design issues including antenna design and amplifier design in the front end. Amplifier design is summarized by first presenting the challenges associated with characterizing and measuring mmWave signals. To address these challenges, S-parameters and Y-parameters are defined, and the design/cost issues that surface with different technologies including GaAs, InP, SiGe, and CMOS are interpreted. Circuit design at traditional frequencies (<10 GHz) takes advantage of lumped element assumptions because circuit dimensions are much smaller than the wavelength of the carrier frequency. Unfortunately, with mmWave frequencies, these assumptions cannot be made. This problem is discussed in detail via transmission line modeling followed by a summary of the design of passive and active elements in mmWave circuits. The key analog circuit components of mmWave transceivers are covered in detail in Chapter 5, and the chapter concludes with a novel and powerful figure of merit, the consumption factor, for determining and comparing power efficiencies for any mmWave circuit or system.

Chapter 6 discusses digital baseband issues. Much of the discussion is devoted to analog-to-digital conversion (ADC) and digital-to-analog conversion (DAC), as this consumes a substantial amount of power in mmWave circuit implementations. The impact of device fabrication mismatch, design architectures, fundamentals of DAC and ADC circuit design, and promising techniques for achieving multi-Gbps sampling and signal reproduction are given in this chapter.

Chapter 7 presents the design and applications of mmWave systems through a summary of 60 GHz PHY algorithms. The design of 60 GHz baseband algorithms is intrinsically linked to the wireless channel and hardware constraints discussed in Chapters 3 through 6. This relationship between the constraints and the PHY design is presented in the beginning of this chapter. Following this discussion, PHY design rules within these constraints are offered through sections on modulation, coding, and channel equalization. This chapter ends with a section that analyzes the impact of future/emerging hardware technology and its ability to relax certain design constraints for mmWave PHYs.

Chapter 8 reviews higher layer (above the PHY) design issues for mmWave systems with a particular emphasis on techniques relevant to 60 GHz and emerging cellular and backhaul systems. The use of directional beam steering, the limited coverage of mmWave signal propagation, and sensitivity to effects like human blockage of dominant signal paths present challenges that must be addressed at higher layers. This chapter reviews the key problems from a higher layer-perspective then expands on select topics in more detail. First, the incorporation of beam steering into a MAC protocol is described in more detail. Then, multihop operation using relays is reviewed as a way to achieve better coverage and to provide resilience to human blockages. Next, because multimedia is an important application for indoor systems, the cross-layer incorporation of video using unequal error protection is described in more detail. Finally, multiband strategies are discussed in which low frequency control signals are used to make network establishment and management easier.

Chapter 9 concludes the technical content of this text with a review of design elements from the standardization efforts for 60 GHz wireless communication systems. Three different WPAN standards are presented including IEEE 802.15.3c for WPAN, Wireless HD for uncompressed high-definition video streaming, and ECMA-387. Each of these WPAN standards has a distinct approach to the physical and MAC layer of the wireless communication system design, and these differences will be highlighted in this chapter. Two different WLAN standards are also presented including IEEE 802.11ad and WiGig (from which IEEE 802.11ad was based), which stretch WLAN into gigabit capabilities through 60 GHz spectrum.

1.5.1 Illustrations for this Textbook

You can find the color versions of the illustrations in this book at informit. com/title/9780132172288.

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