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Why NCC Should Allow ISPs To Use ISM Bands Despite ITU
December 24, 2003
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:
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:
Commercial Operation in the ISM Frequency Bands
The use of ISM
bands (2.4G, 5.8G etc) for commercial purposes has been a hot topic of
discussion over the years. Since taking over the management of commercial
spectrum from Ministry of Communications in January, 2002, NCC has reviewed the
situation and consulted widely and also studied the issue as it obtains in other
countries of the world. Relevant ITU and FCC publications on the issue have
also been studied. It as been discovered that users in this band do not keep
to the regulations guiding the use of these bands, such as low transmitter
power, deployment over short distances etc. Also, there is no protection
against interference in this band, hence it is difficult to monitor or guarantee
the quality of service being offered to subscribers. This is a regulatory
obligation and NCC is committed to consumer protection.
NCC extends ISM band deadline
APPARENTLY deferring to industry activists, the Nigerian Communications Commission (NCC), has extended the deadline issued to commercial service operators to quit the industrial, scientific and medical (ISM) band. The telecommunications regulator has now given the operators up till December 31, this year to quit the unlicensed frequency band. The quit order issued by NCC only last year was to have come into effect by the end of this month. Various representations have since been against the order especially by members of the Internet Service Providers Association of Nigeria (ISPAN)…..
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.
A CRASH COURSE IN RADIO FREQUENCY AND FREQUENCY MANAGEMENT
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:
G013. What is meant
by ISM applications and how are the related frequencies used?
· 5.138 The following bands: 6765-6795 kHz (centre frequency 6780 kHz), 433.05-434.79 MHz (centre frequency 433.92 MHz) in Region 1 except in the countries mentioned in RR No. 5.280, 61-61.5 GHz (centre frequency 61.25 GHz), 122-123 GHz (centre frequency 122.5 GHz), and 244-246 GHz (centre frequency 245 GHz) are designated for industrial, scientific and medical (ISM) applications. The use of these frequency bands for ISM applications shall be subject to special authorization by the administration concerned, in agreement with other administrations whose radiocommunication services might be affected. In applying this provision, administrations shall have due regard to the latest relevant ITU-R Recommendations.
· 5.150 The following bands: 13553-13567 kHz (centre frequency 13560 kHz), 26957-27283 kHz (centre frequency 27120 kHz), 40.66-40.70 MHz (centre frequency 40.68 MHz), 902-928 MHz in Region 2 (centre frequency 915 MHz), 2400-2500 MHz (centre frequency 2450 MHz), 5725-5875 MHz (centre frequency 5800 MHz), and 24-24.25 GHz (centre frequency 24.125 GHz) are also designated for industrial, scientific and medical (ISM) applications. Radiocommunication services operating within these bands must accept harmful interference, which may be caused by these applications. ISM equipment operating in these bands is subject to the provisions of RR No. 15.13.
G014. What should the
frequency spectrum management authority of each country take into account when
· Are there other mandatory Radio Regulations provisions that are governing the use of frequencies (mandatory channeling arrangement, power limits)?
· Is the band concerned subject to a pre-established international assignment or allotment plan; are the characteristics of the assignment in accordance with the appropriate entry in the plan; is there a need to apply the plan modification procedure prior to issuing a license?
· Is there a need for effecting the coordination procedure prior to notification of the concerned assignment to the Radiocommunication Bureau or prior to its bringing into use, is the procedure mandatory or voluntary, is the procedure specified in the Radio Regulations or in a special agreement?
· Is there a need to notify the frequency assignment to the Radiocommunication Bureau, when such notification should be made, which characteristics are to be notified, what action should be foreseen after the recording or otherwise of the frequency assignment concerned?
THE ITU REGULATIONS – AND NCC’S LOGIC
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:
Rec. ITU-R SM.1056 of 1994 (Pp 5-6)
3. Radiation levels inside the bands designated for ISM applications
There are at least five reasons for setting in-band limits for ISM equipment, which are:
– to control bio-effects;
– to minimize out-of-band emissions for the protection of radio services;
– to minimize in-band emissions for the protection of radio services operating in the ISM bands;
– to minimize radio emissions for the protection of adjacent band radio services;
– to minimize radio emissions to protect electronic or radio services operated in the immediate vicinity of ISM equipment.
The limits and methods of measurement and methods employed for bio-effects compliance are outside the scope of the ITU and the CISPR and therefore bio-effect could not be used for setting in-band limits. However, it has been observed that, in many cases, compliance with the biological effects limits has not substantially reduced radiation levels at CISPR measuring distances.
It should be noted reducing in-band radiation does not necessarily reduce out-of-band radiation, and that the out-of-band radiation can increase through suppression of in-band signals.
In-band limits to protect in-band radio services have not been considered because the services to be protected have not been specified. Furthermore, the setting of restrictive limits will decrease the usefulness of the ISM bands for industrial purposes. The result of this would be to encourage the use of ISM equipment in frequency ranges more suitable to their processes, but detrimental to radio services.
The use of in-band limits to protect radio services adjacent to the ISM bands or to protect electronic or radio equipment in the vicinity of ISM operations is more properly dealt with as an equipment immunity issue. Therefore, this is best resolved by ensuring necessary distance separation or by incorporating adequate immunity characteristics in potential victim equipment. However, the calculation and realization of immunity is practical only if the field strengths to be encountered in practice are known. For this reason, the following table of measured levels of radiation based on measurements in a number of different countries is supplied.
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:
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
ITU Internet Reports: Birth of Broadband [Executive Summary] – September 2003, International Communication Union (ITU)
The ISM Frequency Band and Internet Service in Nigeria
Emerging Technology: Wireless Lan Standards
Andy Dornan; Network Magazine; 02/06/02
Wireless LAN Technology
SUNDAY MUSINGS: Resolving the interconnectivity battle in Nigeria -
Some suggestions” Mobolaji Aluko, November 16, 200
MID-WEEK ESSAY: The Arithmetics of PMB, PSB and Interconnectivity Telecommunications Charges in Nigeria; Mobolaji E. Aluko; December 11, 2003
ISM equipment in current use
Source: Rec. ITU-R SM.1056 of 1994
Range of measured levels of field strength from ISM equipment
in the ITU-designated ISM bands
(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
Various broadband technologies, summary
* See Note 4
Rec. ITU-R SM.1056 1
RECOMMENDATION ITU-R SM.1056
LIMITATION OF RADIATION FROM INDUSTRIAL,
SCIENTIFIC AND MEDICAL (ISM) EQUIPMENT
(Question ITU-R 70/1) (1994)
Rec. ITU-R SM.1056
The ITU Radiocommunication Assembly,
a) that No. 16 of the Radio Regulations (RR) defines ISM applications (of radio-frequency energy) as operation
of equipment or appliances designed to generate and use locally radio-frequency energy for industrial, scientific,
medical, domestic or similar purposes, excluding applications in the field of telecommunications;
b) that ISM equipment has the potential to cause harmful interference to radiocommunication services and
applications throughout the spectrum;
c) that for the optimum use of the frequency spectrum, it is necessary to lay down limits of radiation from ISM
equipment outside the bands designated for their use;
d) that the World Administrative Radio Conference (Geneva, 1979) (WARC-79) with its Resolution No. 63
invited the ITU-R to specify, in collaboration with the International Electrotechnical Commission/International Special Committee on Radio Interference (IEC/CISPR), limits to be imposed on radiation from ISM equipment inside and outside the bands designated in the RR for their use;
– that limits shall be specified in the entire radio spectrum allocated to radio services;
– that different radio services need different grades of protection and that the specific protection
requirements of safety services and safety communications need to be taken into account;
– that the use of radio-frequency energy for industrial, scientific, medical and domestic purposes is
beneficial for the economy and the consumers, and is essential for a number of these applications;
e) that due to the different operating environments and characteristics of ISM equipment several categories of
limits are necessary;
f) that radio services operating in the bands designated for use by ISM equipment prior to WARC-79 are required
to accept harmful interference and that radiation limits are necessary in all other bands to protect radio services;
g) that radiation from ISM equipment may be costly and technically difficult to suppress and thus development of
suppression requirements must take into consideration physical, technological, economic, operational and safety aspects of ISM usage to avoid unnecessarily severe measures;
h) that equipment meeting the radiation limits, which are compromise values, may in some circumstances cause
harmful interference; and, there needs to be provisions for measures to be taken to eliminate or reduce interference in individual cases;
j) that the legal and administrative provisions differ in different countries and thus administrations have different
methods of applying and enforcing limits;
k) that the CISPR has developed limits and taken into account the principles outlined in § f) and g) and the
requirements to harmonize the procedures for the control of interference in order to eliminate technical barriers to trade;
l) that the interference potential depends on the location of ISM equipment within the user’s premises and that
the measuring distance and the point of reference for in situ measurements have to be taken into account;
m) that severe difficulties could arise if different limits were to be recommended by different international bodies
for the same class of equipment,
1. that, for ISM applications, the frequencies typically used by ISM equipment and some current and future ISM
applications are shown in Annex 1;
2. that, although the ITU has designated specific frequency bands for ISM applications, other operating
frequencies are also being used where practical constraints do not permit the usage of the designated bands;
3. that CISPR Publication 23 “Determination of limits for industrial, scientific and medical equipment” provides
details of the derivation of limits;
4. that information technology equipment (ITE) and RF lighting devices which use RF energy have not been
considered by the CISPR as ISM equipment and CISPR Publications 15 and 22, respectively, contain a guide for the
application of limits and methods of measurements,
1. that administrations consider the use of the latest edition of CISPR Publication 11, including amendments, as a
guide for the application of limits and methods of measurements for ISM equipment regulation in order to protect
2. that there should be continued cooperation with the CISPR to ensure that radiocommunication needs are fully
taken into consideration.
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