Short-range Wireless Communication

Alan Bensky

• Publisher: Newnes
• Year: 2019
• Print ISBN: 9780128154052
• eBook ISBN: 9780128154069
• Edition: 3
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Short-range Wireless Communication, Third Edition, describes radio theory and applications for wireless communication with ranges of centimeters to hundreds of meters. Topics covered include radio wave propagation, the theory of antennas and transmission lines, architectures of transmitters, and radio system design guidelines as a function of basic communication parameters, such as sensitivity, noise and bandwidth. Topics new to this edition include MIMO, metamaterials, inductance coupling for loop antennas, very high throughput Wi-Fi specifications, Bluetooth Low Energy, expanded coverage of RFID, wireless security, location awareness, wireless sensor networks, Internet of Things, millimeter wave and optical short-range communications, body area networks, energy harvesting, and more. Engineers, programmers, technicians and sales management personnel who support short-range wireless products will find the book a comprehensive and highly readable source to boost on-the-job performance and satisfaction. - Presents comprehensive, up-to-date coverage of short-range wireless technologies - Provides an in-depth explanation of wave propagation and antennas - Describes communication system components and specifications, including transmitters, receivers, frequency synthesizers, sensitivity, noise, distortion, and more - Includes an introduction to error detection and correction

Chapter 1

Introduction

Abstract

This chapter introduces the book with an historical perspective on short-range radio, followed by applications and characteristics that show the focus of its content. Distinguishing features of short-range radios include power output up to 100 mW with a communication range from centimeters up to several hundred meters, omnidirectional built-in antennas, relatively low price for consumer use and unlicensed operation. In addition, they are principally used indoors and often have battery operated mobile terminals. The chapter briefly describes the elements of wireless communication systems. They include the data source, radio frequency generation, RF conduction and radiation, the radio channel, receivers and finally power supplies. An overview of all following chapters is given in this chapter.

Keywords

Garage door opener; Superregenerative receiver; Security systems; Short-range radio; Unlicensed operation; Emergency alarms; RFID; Keyless entry; IoT

1.1 Historical perspective

A limited number of short-range radio applications were in use in the 1970s. The garage door opener was one of them. An L-C tuned circuit oscillator transmitter and superregenerative receiver made up the system. It suffered from frequency drift and susceptibility to interference, which caused the door to open apparently at random, leaving the premises unprotected. There still may be similar systems in use today, although radio technology has advanced tremendously. Even with greatly improved circuits and techniques, wireless replacements for wired applications—in security systems for example—still suffer from the belief that wireless is less reliable than wired and that cost differentials are too great to bring about the revolution that cellular radio has brought to telephone communication.

Few people will dispute the assertion that cellular radio is in a class with a small number of other technological advancements—including the proliferation of electric power in the late 19th century, mass production of the automobile, and the invention of the transistor—that have profoundly affected human lifestyle in the last century. Another development in electronic communication within the last 30 or so years has also impacted our society—satellite communication—and its impact has come even closer to home with the spread of direct broadcast satellite television transmissions.

That wireless techniques have such an overwhelming reception is not at all surprising. After all, the wires really have no intrinsic use. They only tie us down and we would gladly do without them if we could still get reliable operation at an acceptable price. Cellular radio has been of lower quality, lower reliability, and higher price generally than wired telephone. Even though each generation brings it closer to parity on all counts, its acceptance by the public is nothing less than phenomenal. Imagine the consequences to lifestyle when electric power is able to be distributed without wires!

Considering the ever-increasing influence of wireless systems in society, this book was written to give a basic but comprehensive understanding of radio communication to a wide base of technically oriented people who either have a curiosity to know how wireless works, or who will contribute to expanding its uses. While most chapters of the book will be a gateway, or even a prerequisite, to understanding the basics of all forms of radio communication, including satellite and cellular systems, the emphasis and implementations are aimed at what are generally defined as short-range or low-power wireless applications. These applications are undergoing a fast rate of expansion, in large part due to the technological fall-out of the cellular radio revolution.

1.2 Reasons for the spread of wireless applications

One might think that there would be a limit to the spread of wireless applications and the increase in their use, since the radio spectrum is a fixed entity and it tends to be depleted as more and more use is made of it. In addition, price and size limitations should restrict proliferation of wire replacement devices. However, technological developments defy these axioms.

• • We now can employ higher and higher frequencies in the spectrum whose use was previously impossible or very expensive. In particular, solid-state devices have been developed to amplify at millimeter wavelengths, or tens of gigahertz. Efficient, compact antennas are also available, such as planar antennas, which are often used in short-range devices. The development of surface acoustic wave (SAW) frequency-determining components allow generation of UHF frequencies with very simple circuits.
• • Digital modulation techniques have largely replaced the analog methods of previous years, permitting a multiplication of the number of communication channels that can occupy a given bandwidth.
• • We have seen much progress in circuit miniaturization. Hybrid integrated circuits, combining analog and digital functions on one chip, and radio-frequency integrated circuits are to a large part responsible for the amazingly compact size of cellular telephone handsets. This miniaturization is not only a question of convenience, but also a necessity for efficient design of very short-wavelength circuits.

1.3 Characteristics of short-range radio

“Short-range” and “low-power” are both relative terms, and their scope must be asserted in order to see the focus of this book. Hardly any of the applications that we discuss will have all of these characteristics, but all of them will have some of the following features:

• • RF power output of several microwatts up to 100 milliwatts
• • Communication range of centimeters up to several hundred meters
• • Principally indoor operation
• • Omnidirectional, built-in antennas
• • Handheld, mobile terminals
• • Simple construction and relatively low price in the range of consumer appliances
• • Unlicensed operation
• • Noncritical bandwidth specifications
• • UHF operation
• • Battery-operated transmitter or receiver

Our focus on implementation excludes cellular radios and wireless telephones, although an understanding of the material in this book will give the reader greater comprehension of the principles of operation of those ubiquitous devices.

1.4 Short-range radio applications

Table 1.1 lists some short-range radio applications and characteristics that show the focus of this text.

Table 1.1

Short-range radio characteristics

Application	Frequencies (MHz)	Characteristics
Security Systems	300-500, 800, 900	Simplicity, easy installation
Emergency Medical Alarms	300-500, 800	Convenient carrying, long battery life, reliable
Computer Accessories—mouse, keyboard	UHF	High data rates, very short range, low cost
RFID	100 kHz—2.4 GHz	Very short range, active or passive transponder
WLAN	2.4, 5-6 GHz	High continuous data rates, spread spectrum and OFDM modulation
WPAN	2.4 GHz	Medium data rates, low cost
Wireless Microphones; Wireless Headphones	VHF, UHF	Analog high fidelity voice modulation, moderate price
Keyless Entry—Gate, car door openers	UHF	Miniature transmitter, special coding to prevent duplication
Wireless bar code readers	900 MHz, 2.4 GHz	Industrial use, spread spectrum, expensive
Wireless power meters	2.4 GHz	Realtime measurement of electricity consumption and instantaneous demand
Internet of Things (IOT)	UHF, 2.4 GHz	Wireless monitoring and control of appliances and industrial apparatus with minimum human intervention

A new direction in short-range applications has appeared in the form of high-rate data communication devices for distances of several meters. This is being developed by the Bluetooth consortium of telecommunication and PC technology leaders for eliminating wiring between computers and peripherals, as well as wireless internet access through cellular phones. Several other standards have been d...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Preface
• Engineering Worksheets
• Abbreviations
• Chapter 1: Introduction
• Chapter 2: Radio propagation
• Chapter 3: Antennas and transmission lines
• Chapter 4: Communication protocols and modulation
• Chapter 5: Signal generation and transmitters
• Chapter 6: Receiver and digital radio architectures
• Chapter 7: Radio system design
• Chapter 8: System implementation
• Chapter 9: Introduction to information theory and coding
• Chapter 10: Regulations and standards
• Chapter 11: Wireless local area networks
• Chapter 12: Wireless personal area networks
• Chapter 13: Radio frequency identification (RFID)
• Chapter 14: Technologies and applications
• Index