Going Wi-Fi: A Practical Guide to Planning and Building an 802.11 Network

From the earliest use of radio for ship-to-shore and ship-to-ship communications it was apparent that in time there would be a need to coordinate the use of the airwaves that these transmissions traversed. Without such coordination, radio communications would become chaotic. Mutual interference would make radio reception so unreliable as to be virtually useless.

The number of services that occupy the radio spectrum has grown considerably since the first wireless Morse Code transmissions of the late 19th century. Most readers, however, probably take spectrum for granted and perhaps don't fully understand just how important spectrum is to society. With a little thought, however, it's easy to understand that it is what makes television, communications for emergency services, marine transportation, and the space program possible.

But this spectrum is strictly regulated. To understand the full importance of the influence that governmental regulatory bodies have over services that traverse the airwaves, it's good to have a little knowledge of what happened in the past with regards to spectrum regulation.

The notion that electrical communications devices need regulation has its origins in the mid-1800s long before commercial wireless use of spectrum began (indeed long before electromagnetic waves were recognized as such). But the most influential regulations, inasmuch as Wi-Fi is concerned, came about when it was realized that radio equipment was easily thrown off when signals of the same frequency from more than one source overlapped. The regulators referred to this phenomenon as "interference." But, in this instance, they got the term wrong. The waves sent out by different transmitters don't actually interfere with each other; instead, they pass right through each other unchanged. The interference occurs at the receiver when its antenna picks up multiple signals of the same frequency and has trouble telling them apart. With suitable, unique encoding schemes, however, more than one signal can share the same set of frequencies. In other words, interference is a function of the intelligence (or lack thereof) designed into the transmitter and receiver, not purely a result of what happens in the airwaves.

For the purposes of this section (and book), the pivotal historical date is 1865, since that was when representatives from 20 European States decided to meet in Paris, France and work out a framework agreement for the international operation of the telegraph. Now that telegraph lines were beginning to span oceans and connect different countries, international tariffs and standard operating instructions had to be agreed upon by all the nations involved.

The members of this first International Telegraph Convention took it upon themselves to draw up a set of common rules that standardized equipment, which would guarantee generalized interconnection. On the 17th of May 1865 the delegates signed an agreement introducing new charging zones, new telegram categories, etc. The convention also adopted uniform operating instructions, which had hitherto been different from one country to another, and it laid down common international tariff and accounting rules. This gathering also established the International Telegraph Union to facilitate subsequent amendments to the initial framework agreement and they adopted the first spectrum regulations, commonly referred to as the "Telegraph Regulations."

The next date of importance within the context of this book is 1896, the year wireless telegraphy, the first type of radiocommunication, was invented. Wireless telegraphy quickly became invaluable to the maritime industry and it wasn't long before an international set of regulations governing wireless telegraphy was implemented. The first "International Radiotelegraph Conference" (attended by 29 member countries) was convened in Berlin in 1906. These rules, which have since been amended and revised by numerous radioconferences held throughout the years, are now known as the "Radio Regulations." They specify the basic regulatory principles still in common use today: the grouping of services into dedicated frequency bands; national allocations reported to a central registration agency, the Berne Bureau; and the partitioning of spectrum frequencies so that those below 188 kHz are to be used for long distance communications and frequencies between 188 kHz and 500 kHz are reserved for military use.

It wasn't long before governments worldwide began declaring that spectrum was a public resource over which they had the authority to license. For instance, in the U.S., the Radio Act of 1912 was adopted to address the issue of radio wave interference by limiting the wavelengths over which stations could transmit. That same year, the International Radiotelegraph Conference (IRC) published the first attempt at an International Table of Frequency Allocations. Member states' adherence to the Table was non-mandatory.

The next important step in international spectrum regulation and management occurred in 1920 at the Preliminary World Conference on Electrical Communications held in Washington, D.C. Several important proposals were introduced at that meeting. They include the merger of the Telegraph and Radiotelegraph conventions into a single Universal Electrical Communications Union (which was a blueprint for what would become today's International Telecommunications Union) and a spectrum allocation process that would require international approval before use.

When the International Radiotelegraph Union held its 1927 meeting in Washington, D.C., 80 countries participated. At that meeting a number of important issues were decided. The organization's responsibility was broadened beyond maritime transmitters to all radio transmitters. A scheme was established to allocate frequency bands to various radio services that were in existence at the time (fixed, maritime and aeronautical mobile, broadcasting, amateur, and experimental) so as to ensure greater efficiency of operation in view of the increase in the number of radiocommunication services and the technical peculiarities of each service. Also, the first comprehensive International Table of Allocations was introduced and the International Radio Technical Consulting Committee (CCIR) was established to study technical issues.

Then in 1932, at a joint Telegraph and Radiotelegraph Conference in Madrid, the two conventions were merged into a single organization entitled the International Telecommunications Union or ITU. The new name, which didn't become effective until January 1, 1934, was chosen to properly reflect the full scope of the ITU's responsibilities, which by that time covered all forms of communication, wire and wireless, radio, optical systems and other electromagnetic systems. In 1947, the ITU became a specialized agency of the United Nations.

In the U.S., the Radio Act of 1927 attempted to deal with the increasingly complicated issue of spectrum regulation, but it was the Communications Act of 1934 that gave birth to the Federal Communications Commission and gave the agency authority to regulate every aspect of any spectrum not used by the U.S. government.

Another year that holds particular importance to the spectrum regulatory system is 1947. That was when the 1947 ITU Atlantic City conference approved the ITU's United Nations status; established the International Frequency Registration Board (IFRB) to manage the frequency spectrum (which was becoming increasingly complicated); and mandated that adherence to the International Table of Frequency Allocations (introduced in 1912) would be compulsory. That Table assigns, to each service using radio waves, specific frequency bands with a view to avoiding interference between stations-in communications between aircraft and control towers, car telephones, ships at sea and coast stations, radio stations or spacecraft, earth-based stations, and so forth. More important, full membership status was limited to sovereign nations, with each nation allotted one vote, regardless of its size. "Sector" membership status was open to telecommunications operators, broadcasters, and organizations. (Prior to the 1947 Conference, the latter group had full membership status.) This membership reorganization substantially increased the influence of small or developing countries in a manner totally unrelated to industrial wealth or telecommunications usage.

In 1956, the International Telephone Consultative Committee (founded in 1924) and the International Telegraph Consultative Committee (founded in 1925) were merged to form a very influential European agency called the Comité Consultatif International Télégraphique et Téléphonique (CCITT), which translates to the "International Telephone & Telegraph Consultative Committee." The CCITT was charged with the responsibility of coordinating the technical studies, tests and measurements being carried out in the various fields of telecommunications, as well as drawing up international standards.

In 1959, the initial Radio Regulations were entirely re-written, for the first time, by the Geneva Administrative Radio Conference. This same year also saw the establishment of the European Conference of Postal and Telecommunications Administrations, which is commonly known as "CEPT." The original members were the incumbent monopoly-holding postal and telecommunications administrations, but today CEPT's activities include cooperation on commercial, operational, regulatory and technical standardization issues.

The Asia Pacific Telecommunity (APT) was created in 1979 in Bangkok. The APT has four major activities: technical assistance to the developing countries of the region, a regional information and communications technology (ICT) forum, a telecommunications standards forum, and a radio regulatory forum, which is known as the APG.

In the early 1990s, many of the regulatory agencies around the world began to auction spectrum, which generated hundreds of billions of dollars in revenue for their governments. With "good" spectrum seeming increasingly scarce, communications providers were forced to pledge huge sums of money to acquire available spectrum, with little hope that they would ever recoup their costs.

With the beginning of the new millennium, CEPT felt some reorganization was needed within its ranks if it was to meet the upcoming challenges of convergence in the radio and telecommunications market. Two of its offices, ERO (European Radiocommunications Office) and ETO (European Telecommunications Office), were brought under the umbrella of a new entity, the Electronic Communications Committee (ECC).

On January 31, 2002, the ERO launched a new European Frequency Information System (EFIS), which is available to the public on the Internet either via the ERO website (www.ero.dk) or the EFIS website (www.efis.dk). With this tool, the ERO hopes to provide a valuable service to all parties with an interest in spectrum utilization. The EFIS will also contribute to the CEPT policy objectives of harmonization and transparency as well the European Union's policy objectives laid down in the Decision of the Council and European Parliament on Radio Spectrum Policy. (You can find a copy of this document at www.etsi.org/public-interest/Documents/Legislation/2002_676.pdf.)

With EFIS you can search for and compare spectrum utilization across Europe as well as related information such as CEPT activities, radio interface specifications, and other national or international regulations. Another of ERO's objectives is to develop proposals for a "European Table of Frequency Allocations and Utilizations" for the frequencies 29.7 MHz to 105 GHz. This table is slated for implementation by June 2008. A significant proportion of the input to develop such a table was provided by a process of Detailed Spectrum Investigations (DSI), where portions of the radio spectrum were studied in depth to identify current use and future requirements. The results of the DSI study were published in ERC Report 25, which can be found at www.ero.dk/doc98/official/pdf/rep025.pdf.

In fact, much of the information the reader might need on European spectrum allotment, allocation, assignment, and management can be found at either www.ero.dk or www.eto.dk. Both websites contain a treasure trove of up-to-date information.