alukome@aol.com

Let me begin this rather technical essay with an excerpt from the International Telecommunication Union’s (ITU) website posted about broadband in Africa

on December 15, 2003:

QUOTE

'Unconventional' Broadband Deployments Drive African Bandwidth Growth

World Markets Research Centre (registration required) has an interesting study on broadband in Africa. According to the article, classic broadband services are being introduced by a handful of Africa's leading public telecommunications operators. However, wireless broadband and unconventional deployments by internet service providers, wireless operators and regional satellite service providers are building new, faster pathways from the customer to the internet backbone. Although broadband statistics in Africa are scarce, the nebulous 'broadband' market is probably the most dynamic sector in Africa. Some of the key findings of the study are as follows:

In April 2003, The ITU Strategy and Policy Unit (SPU) hosted a workshop on the different strategies used by ITU Member States in promoting the deployment and use of broadband networks. The ITU has since released a more in-depth analysis in its Birth of Broadband report

UNQUOTE

It is one of these "unlicensed ISM bands" – the 2.4 GHz band, which indeed is currently contributing to prolific broadband access [See Note 1] deployment in Nigeria – that the regulatory body National Communication Commission (NCC) in Nigeria wishes to completely restrict all ISPs from effective December 31, 2003 after a grace period since February:

QUOTE

http://www.ncc.gov.ng/Press%20Releases/commercial_operation_ism.htm

Commercial Operation in the ISM Frequency Bands

http://www.dailytimesofnigeria.com/DailyTimes/2003/February/10/NCC.asp

NCC extends ISM band deadline

UNQUOTE

Despite the fact that frequency management is absolutely essential in telecommunications in order to avoid undue interference, my claim here is that NCC’s latest order is inappropriate, and is most likely a result of a wrong reading of the intended purpose of ISM regulation by the ITU. [See Note 2.]

Let me explain.

Think of a wave as something that goes up and down continuously, repeating in cycles. The height difference between the highest point and the lowest point is a measure of the amplitude of the wave. How many times the "something" repeats in a second is measured by the number of Hertz. [See Note 3]. Therefore, for example, roughly in ascending magnitude of frequency: alternating current repeats at 50 Hertz (50 cycles per second) in the US and 60 Hertz in Nigeria; AM Radio receives in the 535 KHz to 1.7 MHz band; Short wave radio bands from 5.9 MHz to 26.1 MHz; Citizens band (CB) radio in 26.96 to 27.41 MHz ; garage door openers and alarms operate around 40 MHz, Television stations channels 2 through 6 are at 54 to 88 megahertz, FM radio between 88 to 108 MHz ; Television stations Channels 7 through 13 are 174 to 220 MHz; analog mobile phones operate at 800 MHz; Air traffic control radar is between 960 to 1,215 MHz; GSM (digital mobile) in Nigeria and Europe operates at 900 MHz and 1,800 MHz (at 1,900 MHz in the US), Global Positioning System between 1,227 and 1,575 MHz; microwave oven typically operate at 2.5 GHz, C-band satellite transmission is in the 4 – 6 GHz range; the recently licensed FWA licensed frequency in Nigeria is at 3.5GHz AND 10.5 GHz (even though only the former has been exercised), Ku-band satellite transmission is in the 12 – 14 GHz range; Ka satellite band is in the 33 GHz – 36 GHz range; red color is a wave at 430 trillion Hz (430 THz) and violet is 750 THz, while gamma rays are 3 billion billion Hz! Radio waves are those with a few KHz to several GHz., while microwaves are a subset of radiowaves – roughly between 890 MHz and 20 GHz (sometimes considered between 1 GHz and 30 GHz.), the rest just being part of the electromagnetic spectrum.

I must admit that I have mixed up all types of signals here – electrical, sound, light, etc., but you get the point that very many telecommunications and non-telecommunications equipment transmit and receive waves at various frequencies, some of them overlapping in the same frequency range. Whenever different waves of same or very nearly similar frequency overlap each other within the same geographical area – maybe in a room, a campus or even a city - there is greater tendency to either cancel each other out (that is, amplitude becomes zero when the "up" of one wave occurs at the same time as the "down" of two completely out-of-phase waves of the same amplitude), or enhance each other’s amplitude in a manner that was not originally intended. So such interference is to be avoided, and both international as well as local regulation might be necessary to limit that interference severely.

The overwhelming amount of non-telecommunication equipments can be categorized into industrial, scientific and medicinal (ISM) types, hence it is convenient to classify wave transmit/receive equipments into two broad classes: telecommunications and ISM equipment.

Since ISM equipment are NOT telecommunications equipment, there is no need for them to send their waves very long distances, nor is it necessary for them to be receiving such waves from a long distance. Whether any equipment transmits its waves FAR – what is far is relative – depends on its transmitting POWER, measured in EIRP (effective Isotropic radiated power). A microwave oven, as it heats say rice within its chambers, only needs its waves to be confined to within the chamber, so it need not emit waves that will extend to beyond the walls of the oven – ie it need only be fitted with a wave emitter whose power limits the wave’s reach. However, the transmitter in a base station of a GSM cell may need to transmit/receive radially up to 3 miles or even 15 miles, and it must have a receiver/transmitter (the mobile handset) with matching frequency but and with less power.

Note that even if two equipments emit at the same frequency, if they are not within the same geographical zone – or better yet if they are far apart - they do not interfere appreciably with each other.

The whole purpose of frequency management, therefore, is to assign frequencies to different equipment, and to ensure that they are used in such a manner that interference between them is at a minimum.

In fact, as elaborated in the following response to "Frequently Asked Question about Notification", some of the ISM bands are SPECIFIC to various countries:

QUOTE

http://www.itu.int/ITU-R/terrestrial/pub-reg/faq/#g013

UNQUOTE

Examples of ISM equipment include ultrasonic cleaners at 15-30 kHz, surgical diathermy and RF arc-stabilized welders at 1 – 10 MHz; medical diathermy at 27 Mhz; Magnetic resonance imaging at 10 – 100 Mhz; and domestic and commercial microwave ovens as well as rubber vulcanizers at 2.4 Ghz – which is the current ISM band in question in Nigeria [See Table 1 below.] The ITU-designated bands themselves and range of measured field strengths are given in Table 2.

The irony of the matter is that it is the power of ISM equipment that ITU intended to regulate, not that of telecommunications. The idea is as follows: we shall not license designated ISM frequencies so that manufacturers of ISM equipment useful to mankind of do not have to pay to use those frequencies. But we don’t mind if telecommunications equipment manufacturers also use those frequencies, but they must realize that it is UP to them to avoid interferences, and one way to do that is to limit their own power of transmittal. But ISM equipment manufacturers MUST also limit their power of transmittal.

These notions were properly spelt out in ITU Recommendation Rec. ITU-R SM.1056 of 1994 (see an excerpt in Appendix I below), another section of which actually reads as follows:

QUOTE

Rec. ITU-R SM.1056 of 1994 (Pp 5-6)

UNQUOTE

NCC’s regulation therefore BANNING 2.4 GHz use in Nigeria unnecessarily restricts telecommunications – which in fact it should seek to promote over ISM equipments – in a manner which must be quite curious to its international regulator colleagues. The ITU rules are to restrict ISM equipment, not to restrict telecommunications equipments. Virtually nowhere in the world – except perhaps Hungary – are ISM bands banned for use of telecommunications equipment. In fact, it is the other way around: ISM equipments are RESTRICTED from using bands that would interfere with telecommunications equipments!

But one might ask: why would NCC impose the ban in the first instance? My guesses are two-fold:

1. wrong reading of the original intent of the ITU regulation as stated above.
2. a seeming need to ensure that recently-licensed FWA operators (in the 3.5 GHz) who have paid large sums of money can reap the rewards of a migration from the present ISM/ISP users, and hence recoup their money quicker. One would like to know whether this assurance – of banning the 2.4 GHz was part of the deal.

The question one might ask is the following: why pay for a 3.5 GHz license when 2.4 GHz is free? The answer has to do with BANDWIDTH – the "transmission highway" is WIDER at 3.5 GHz than at 2.4 GHz, so that you can drive faster and push more data in the licensed frequency than in the unlicensed one. People are willing to pay for – and use – a 6-lane highway rather than a two-way road. But if all you have is a Volkswagen, a 2-way lane maybe enough for you, while those with a Ferrari may pine for a 6-way lane. Such analogies exist in the information superhighway – in this case between 2.4 GHz and 3.5 GHz.

The other problem with the latter issue is that equipment (modems, switches, coders, decoders, etc.) in the 3.5 GHz range are far fewer than in the 2.4 GHz – they are manufactured in larger quantities in the world - and hence they are more expensive. For example, the exciting world of 802.11 "Wi-Fi" (Wireless Fidelity) is being deployed in the 2.4 GHz band. Thus, a developing country like Nigeria with no manufacturing base for these equipments and no crowding whatsoever in the unlicensed 2.4 GHz band is being asked to dump 2.4Ghz equipment that the ISPs have been using all of these years for more expensive 3.5 GHz due to an unusual regulation that is not applied anywhere else in the world.

That is not fair or proper, and it is one of those times when it is good to leave well enough alone. Despite major strides, we are still far from universal access to telecommunications, and that should be priority of the nation. Thus as a Christmas and New Year present, NCC should lift the ban – and let the ISPs be.

I rest my case.

Note 1: Broadband – digital speeds greater than 264 kilobits per second (264 kbps) are generally considered broadband. Speeds as high as 11 Megabits per second (11 Mbps) are possible. See Table 3 for some broadband technologies and related speeds.

Note 2: The ITU is an intergovernmental organization which is established by Member States – Parties to the Constitution of the International Telecommunication Union - and whose membership is composed of Member States and Sector Members, with rights and obligations that are well defined in its Constitution and its Convention. [For more details of the ITU and its roles, see Reference 1.]

Note 3: 1 GHz = 1,000 MHz = 1,000,000 KHz = 1,000,000,000 Hz

That is 1 GHz = 10^3 MHz = 10^6 KHz = 10^9 Hz

Note 4: ADSL – Asymmeric Digital Subscriber Lane; SHDSL – Single-pair High-bit-rate digital subscriber line; VDSL – Very high-data-rate Digital Subscriber Line; IEEE –Institute of Electrical and Electronics Engineers.

1. ITU: Frequently Asked Questions Related to Notification

http://www.itu.int/ITU-R/terrestrial/pub-reg/faq/;

ITU Internet Reports: Birth of Broadband [Executive Summary] – September 2003, International Communication Union (ITU)

http://www.jidaw.com/itsolutions/telecomm2.html

http://libra.unitbv.ro/internet/technologies/802_11.htm

Emerging Technology: Wireless Lan Standards

Andy Dornan; Network Magazine; 02/06/02

http://www.usg.edu/conferences/networking/wlan.pdf

Wireless LAN Technology

http://www.kwenu.com/publications/aluko/resolving_interconnectivity.htm

http://groups.yahoo.com/group/AlukoArchives/message/129

MID-WEEK ESSAY:  The Arithmetics of PMB, PSB and Interconnectivity Telecommunications Charges in Nigeria; Mobolaji E. Aluko; December 11, 2003

TABLE 1

Source: Rec. ITU-R SM.1056 of 1994

TABLE 2

(1) The field strength is that existing at a distance of 30 m from the boundary of the building in which the ISM equipment is situated. Therefore the actual distance between the ISM equipment and the measuring point is not known. (db = decibels; mV/m is micro-volts per meter)

(2) 896 MHz in the United Kingdom.

Source: Rec. ITU-R SM.1056 of 1994

Table 3

Various broadband technologies, summary

(Source: ITU)

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APPENDIX I

RECOMMENDATION ITU-R SM.1056