Home > Articles > Networking > Wireless/High Speed/Optical

Introduction to Wireless Systems

This chapter introduces the problem of moving information wirelessly from any point A to any point B and how the systems engineer fits into this process.
This chapter is from the book

This chapter is from the book


On the night of April 14, 1912, the RMS Titanic, en route from Southampton, England, to New York, struck an iceberg and sank in the North Atlantic. Over fifteen hundred lives were lost when the ship went down, but fortunately for the more than seven hundred passengers and crew who were able to find accommodation in the ship's lifeboats, the Titanic was equipped with a wireless system. The Titanic's wireless included a 5 kW rotary spark transmitter built by the Marconi Wireless Company. Distress calls were heard by a number of ships at sea, including the Carpathia that arrived on the scene of the disaster several hours later, in time to rescue the survivors.

The wireless traffic between the Carpathia and shore stations in North America was widely monitored. News was passed to the press even before the fate of the Titanic's passengers was known. The widespread publicity given to this disaster galvanized public interest and propelled wireless communication into the forefront of attention. The age of wireless communication might be said to have begun with the sinking of the Titanic.

As social beings, humans have a fundamental need to communicate. As we grow and learn, so do our communication needs evolve. Dramatic advancements over the past century have made several facts about our evolving communication needs rather apparent: (1) The information that needs to be communicated varies widely; (2) the types and amount of information that needs to be communicated continuously change, typically toward higher complexity; and (3) current technology rarely meets communication demands, so technology evolves. These facts, along with a healthy worldwide economy, produced the wireless revolution in the late twentieth century. Wireless communication is here to stay, and the design principles used to create wireless technology differ enough from those used to create wired communication systems that a separate treatment is necessary.

In this text the process of designing a wireless communication system is presented from the perspective of a systems engineer. Two main goals of the text follow immediately: (1) to present the concepts and design processes involved in creating wireless communication systems, and (2) to introduce the process of systems engineering and the role of a systems engineer to provide an organizing framework under which to introduce the wireless system concepts. In the industrial world, the design process flows in an organized manner from problem definition, through conceptual and detailed design, to actual deployment. In this text, information from first principles to advanced topics is presented in a fashion compatible with systems-engineering design processes, which are required to manage the development of complex systems.

In Chapter 1 the problem of moving information wirelessly from any point A to any point B is introduced. In every engineering endeavor it is important to have a clear understanding of the problem to be solved before beginning, and so the system and its requirements are defined. The role of a systems engineer and the methods of systems engineering are introduced as the perspective for conducting our study and design.

Chapter 2 presents the most fundamental element of our wireless system, the radio link that connects points A and B. This chapter addresses two issues: how radio waves propagate in space, and how much power must be provided at point B to ensure a desirable quality of communication service. This chapter focuses on propagation in free space and the development of the range equation, a mathematical model familiar to both radio and radar engineers. We introduce the antenna as a system element and the antenna design engineer as a member of the design team. To answer the question of how much power is enough, we develop models and analysis tools for thermal noise and describe how thermal noise limits performance. Signal-to-noise ratio (SNR) is introduced as a measure of system performance. Finally, the concept of link budget, a fundamental tool for radio frequency (RF) systems engineering, is presented and supported with examples.

Chapter 3 focuses on signal propagation in the real world. Obstacles in the signal path and indeed the very presence of the Earth itself modify a signal as it travels between endpoints. Various terrestrial propagation models are presented and discussed. These models provide methods for predicting how a signal will propagate in various types of environments. The phenomena associated with shadow fading, Rayleigh fading, and multipath propagation are described as well as the effects of relative motion of a receiver and of objects in the environment. Statistical methods are developed that allow engineers to create robust designs in an unstable and changing environment. Receiver design and channel modeling are added to the list of design functions that a systems engineer must understand to competently interact with team members who specialize in these design disciplines.

Given a basic understanding of methods to ensure that an adequate signal can be conveyed between two endpoints, we discuss the concepts and complexities involved in allowing many users in a large area to share a common system. Geographic diversity and frequency reuse are discussed and used as the basis for developing the "cellular" concept in Chapter 4. The cellular concept is the fundamental basis for designing and deploying most wireless communication systems that must provide service for many users over a large geographic area. The chapter describes how engineers using cellular engineering techniques plan for growth in user capacity and coverage area. Traffic engineering and the use of the Erlang formula as tools for predicting and designing a system for user capacity are demonstrated. At this stage of the design, system-level concerns are well above the device or subsystem level.

In Chapter 5 we describe the methods used to convey information over the wireless link. The process for conveying information using a radio signal, called modulation, is described from a trade-off perspective. The characteristics of several digital modulation schemes are developed and their attributes are compared. The key design parameters of data throughput, error rate, bandwidth, and spectral efficiency are contrasted in the context of optimizing a system design. Also in this chapter we introduce spread-spectrum signaling. Spread spectrum is a modulation technique that broadens the bandwidth of the transmitted signal in a manner unrelated to the information to be transmitted. Spread-spectrum techniques are very effective in making signals resilient in the presence of interference and frequency-selective fading. Our study of spread-spectrum techniques continues in Chapter 6, as these techniques provide an important basis for multiple-access communications.

The first five chapters provide all of the fundamental elements of system design for providing radio coverage to many users over a large area and for designing the components that support the conveying of information at a given quality of service (QoS) across a wireless link between individual users. Chapter 6 introduces various methods that allow many users to access the system and to simultaneously use the resources it provides. In this chapter we introduce the classical methods of frequency-division and time-division multiple access, as well as spread-spectrum-based code-division multiple access which allows independent users to share the same bandwidth at the same time. In providing a multiple-access capability, a systems engineer unifies a variety of system-level design activities to make the system accessible to a varying number of users.

People wish to communicate different types of information, and the information they want to communicate comes from a variety of sources. Chapter 7 discusses several of the types and sources of information commonly communicated in contemporary wireless systems. The required QoS that is to be provided to a system's users must be accounted for in nearly every aspect of a system design. Users' perceptions of what constitutes good quality vary for different types and sources of information and always depend on how well a signal representing the information is preserved in the communication process. Chapter 7 discusses some of the fundamental relationships between the perceptual measures of QoS and specific system design parameters. Understanding these relationships allows a systems engineer to design for predictable QoS at minimum cost. As modern wireless systems are designed to carry information in digital form, a major part of this chapter is about efficient digitization of speech. We discuss two general categories of speech "coding": waveform coding and source coding. As an example of the waveform coding technique we examine traditional pulse code modulation (PCM). Our example of source coding is linear predictive coding (LPC). This latter technique has been extremely successful in providing high-quality, low-bit rate digitization of voice signals for cellular telephone applications. Following the discussion of speech coding, the chapter concludes with an example of coding for error control. Convolutional coding is used for this purpose in all of the digital cellular telephone systems. We introduce the coding method and the widely used Viterbi decoding algorithm.

Chapter 8 wraps up the presentation with a review of the lessons developed in the preceding chapters. This is followed by an overview of the generations of cellular telephone systems and a look into the future at the way wireless systems are evolving to provide an increasing array of services at ever-higher quality. As wireless systems evolve, they tend to become more complicated. Thus the role of the systems engineer in managing the design process and in understanding the myriad of design trade-offs and interactions becomes ever more important.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020