The Evolution of Wireless Services anf Broadcast Systems

Completion of Lecture 6: Wireless Technology: Electromagnetic Fields and Radiation

An account of the heterodyne principle

To generate new frequencies by mixing two or more signals
in a nonlinear device such as a vacuum tube, transistor, or diode mixer.
References:

• Reginald Fessenden
• http://collections.ic.gc.ca/heirloom_series/volume4/42-45.htm
• 
  
• History of Radio Transmission
• Recognizing Some of the Many Contributions to the Early Development of Wireless Telegraphy (local copy) by Leonid Kryzhanovsky
• The History of Radio: a historic tour from The World of Wireless
• Some radio highlights
• The evolution of the Regulation and Deregulation of Telecommunications

Radio Communications: A Brief Synopsis
• The Radio Corporation of America Radio Central at Rocky Point, Long Island
• A Chronology of AM Radio Broadcasting: Part 1: 1900-1922
• Radio Macrihanish
• See also A List of Web Tutorials and References: History of Radio

isualizing the Invisible - Electric and Magnetic Fields:

A Brief History of Mobile Communication

See a chronology of mobile communication

Some of the Many Current Mobile Wireless Services

 
CRS (Cellular Radiotelephone Service) bandplan FCC description of service.

Broadband PCS (Personal Communication Services) bandplan and FCC description of service.

Narrowband PCS (Personal Communication Services) FCC description of service.

MDS (MicrowaveDistribution Services)  bandplan

SMR (Specialized Mobile Radio) bandplan and FCC description of service.

WCS (Wireless Communication Services) bandplan and FCC description of service.

The Cellular Concept

Another view of the Cellular Concept

A good place to start is the Cellular Communications Tutorial from the International Engineering Consortium (original) and (local copy).

Lighter treatments:

The Wireless Story is a very helpful demo.

How Does It Work?

Handoff Processes

 
Handoff technology

Personal and Mobile Communications: Handover (or Handoff) from Robert Godon University, Aberdeen has some applets and reference to applets, in particulate this one.

Access Technology

The multiple access schemes provide the means for establishing an autonomous channel in a multi-user environment. There are five multiple access schemes:

FDMA serves the users with different frequency channels.

TDMA serves the users with different time slots.

CDMA serves the users with different code sequences.

SDMA (space division multiple access) users the calls by spot beam antennas.

PDMA (polarization division multiple access) users the calls with different polarization (Not applied to mobile radio)

In the cellular system, the first four multiple access schemes can be applied.  In analog systems, only FDMA and SDMA can be applied. In FDMA and TDMA, each frequency channel or each time slot is assigned to one call. During the call period, no other calls can share the same channel slot.  CDMA presents the opposite case, because all traffic channels are sharing a single radio channel. However, this feature causes that a strong signal received from a near-in mobile unit will mask the weak signal from a far-end mobile unit at the cell site.

Recall our discussion of FMDA and TDMA

We must add to that a discussion of CDMA

Regulatory Issues - FCC Information

The WTB (Wireless Telecommunication Bureau) Homepage

Mobile Base Station Antennas

A Gallery of Typical Base  Station Antennas

A Gallery of "Stealth" Antennas

Monopole as commercial sign I

Monopole as commercial sign II

In a farm silo

Existing building: Schrafft Building

Existing building: Fortress Building

Existing building: Fortress Building (detail)

Existing building: Newton Church

 

Characteristics of Wireless Propagation

Multipath Model of Fading (MATLAB mdl file)

Radio Propagation Models is an extensive review of the characteristics of wireless propagation.

References

GSM: Overview of the Global System for Mobile Communications by John Scourias
Personal and Mobile Communications from the Roberd Gordon University, Aberdeen.