Jidaw Systems
(MASTERCOMPUTERS)


Why NCC Should Allow ISPs To Use ISM Bands Despite ITU

INTRODUCTION

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

http://www.itu.int/osg/spu/newslog/categories/broadband/2003/12/index.html

'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:

Cost of upstream bandwidth suppresses demand. The cost of a 512Kbps circuit in Africa can be 100 times greater than in developed countries, because upstream connectivity into the internet backbone requires an international circuit rather than a local tail. This is a key reason why growth in dial-up internet subscribers has begun to plateau. 

Broadband reaches African countries, but in unconventional ways.
There are a handful of wireline deployments of ADSL, and two CATV implementations. It is the unconventional deployments by ISPs, wireless operators and regional satellite-service providers that are building new, faster pathways from the customer to the internet. In a few isolated cases, ISPs are deploying wireline broadband services where they are able to do so (such as asymmetric digital subscriber line - ADSL - in Ghana), but are typically investing in wireless technologies. Whereas the customer base for wireline broadband vendors is restricted to public telecommunications operators (PTOs), that for wireless equipment includes, in addition to PTOs, thousands of ISPs and dozens of regional operators.

The most prolific broadband deployments use the unlicensed ISM bands. Because of the lack of fixed-line infrastructure, most broadband implementations are wireless, using 802.11 (wireless fidelity - WiFi), broadband fixed-wireless access (FWA), and two-way, Ku-band very small aperture terminal (VSAT). Because the industrial, scientific and medical (ISM) bands are unlicensed and customer equipment is inexpensive, this reduces the costs for service providers and customers. The falling cost of two-way Ku-band VSAT makes it a contender for the medium tier of end users.

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.  It is the band that the regulatory body National Communication Commission (NCC) in Nigeria wishes to completely restrict all ISPs from using, 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

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. 

The Commission therefore wishes to state categorically that ISM bands cannot be used to provide commercial services.  They are only allowed for private use, self-provision or for industrial, scientific and medical applications.  However, in order not to disrupt services to several users who have already subscribed to operators using this frequency; and to also allow the upcoming FWA operators soon to be licensed for fixed wireless service in the 3.5G band to settle down and provide alternative service to customers, the present illegal operators are hereby given up till the end of February, 2003 to vacate the band.  Subscribers are advised to be careful about patronizing any service provider offering wireless access service based on ISM bands as quality cannot be guaranteed and such operators will not be allowed to operate as from end of February 2003.

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

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)…..

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 that it is most likely a result either of a wrong reading of the intended purpose of ISM regulation by the ITU [See Note 2], or an undue need to protect the revenue stream of the recent 3.5 GHz band Fixed Wireless Access (FWA) PTO licensees.

Let me explain.

A CRASH COURSE IN RADIO FREQUENCY (RF) AND FREQUENCY MANAGEMENT

Think of a wave as "something", a signal, that goes up and down continuously, repeating in cycles. The height difference between the highest point (crest) and the lowest point (trough) is a measure of the amplitude of the wave.  The length of a cycle in time units is called its period, in length units is called its wavelength. [See Figure 1.]  How many times the cycle repeats in one second is measured in Hertz. [See Note 3]:  one cycle per second equals 1 Hz, and the longer the period, the shorter the frequency in direct inverse relation.   Therefore, for example, roughly in ascending magnitude of frequencies:  alternating current repeats at 50 Hertz (50 cycles per second) in Nigeria and 60 Hertz in the US; the sounds produced in human speech contain frequencies within the band 100-10 KHz, but the main useful voice frequencies are contained within the band 300 Hz to 3.4 kHz (that is, the "bandwidth" of useful voice frequencies is 3400 - 300 Hz or 3100 Hz or 3.1KHz); audio frequencies detectable (heard) by the human ear are normally considered to lie within the range of 15 Hz to 15 KHz; AM Radio receives in the 535 KHz to 1.7 MHz band; Short wave radio bands are 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 MHz, 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 (PCS system is at 1,900 MHz in the US),  Cordless phones operate at 900MHz, 2.4 GHz and 5 GHz for example, under digital spread spectrum techniques (DSS);  Global Positioning System (GPS) 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 (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;  we feel radiant heat because of infrared waves of  200 to 400 trillion Hz (1 THz = 10^12 Hz), the ROYGBV visible light range spans red color at 430 THz and violet at 750 THz,  X-Rays are in the 10^16 to 10^19 Hz range, while gamma rays are in general greater than 10^19 Hz !  

Radio waves are those with a few KHz to several GHz., while microwaves are a subset of radio waves - roughly between 890 MHz and 20 GHz (sometimes considered between 1 GHz and 30 GHz.), the rest just being part of the electromagnetic spectrum.   If you are more familiar with wavelengths, divide the speed of light (~3 x 10^8 m/s) by the frequencies above to get the wavelengths in meters. Besides wavelength and frequency, waves are characterized by their energy: the wave energy in electron-volts (1 eV = 1.6 x 10^-19 Joules) is obtained by multiplying the frequency (in per second units) by Planck's universal constant h

(h = 4.14 x 10^-15 eV . s = 6.626 x 10^-34 J.s )    [See Figure 2 for a summary of different uses of the electromagnetic spectrum.]

I must admit that I have mixed up all types of signals here - electrical, sound, light, photons, etc., - but you get the point that very many natural processes, 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 a second completely out-of-phase wave 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, or minimized in such a manner as not to degrade the performance of the affected equipments appreciably, and both international as well as local regulation are necessary to ensure that. 

ENTER ISM EQUIPMENT

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 equipments and ISM equipments.

Since ISM equipments are by definition NOT telecommunications equipments, 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 - i.e. it need only be fitted with a wave emitter whose power limits the wave's reach, and regulations exist to ensure that that is the case.  However, the transmitter in a base station of a GSM cell will need to transmit/receive radially, with cell sizes from as little as 200 meters (micro-cells) to macro-cells as much as 35 km (22 miles).   It must also have a mobile receiver/transmitter (the mobile handset) with matching frequency and 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 sufficiently far apart - they do not interfere appreciably with each other.  If same-zone existence cannot be avoided or guaranteed, they can also have immunities built into the equipments to physically shield or dynamically minimize interference by electrical or electronic means.

The whole purpose of frequency management, therefore, is to assign frequencies to different equipments, 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 by ITU 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

G013. What is meant by ISM applications and how are the related frequencies used? 

The term "unregulated frequencies" is not used within ITU texts. What is often meant by the term "unregulated frequencies" is the frequency bands for industrial, scientific and medical (ISM) applications. The international Table of Frequency Allocations, which is contained in Article 5 of the Radio Regulations (Volume 1), specifies some frequency bands that may be made available for ISM applications (see RR Nos. 5.138 and 5.150 reproduced below):

 

·         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 assigning frequencies?

Using the international Table of Frequency Allocations as a starting point, the frequency spectrum management authority of each country normally selects appropriate frequencies with a view to their assigning to stations of a given service. Before taking the final decision to assign a frequency to a station in a given radiocommunication service in a given frequency band and to issue an appropriate license, the authority concerned should be aware of all other conditions that are regulating the use of frequencies in the concerned band, e.g.:

 

·         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? 

UNQUOTE

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; and Magnetic resonance imaging at 10 - 100 MHz. Only a very few equipments such as domestic and commercial microwave ovens as well as rubber vulcanizers  operate 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 frequency-generating power of ISM equipment that ITU EXPRESSLY intended to have regulated, not that of telecommunications equipment.  The idea is as follows, paraphrasing ITU:  "we shall not license designated ISM frequencies so that manufacturers of ISM equipment useful to mankind do not have to pay anybody to use those frequencies.  Also, their radiation-dependent equipment can be used globally.  But we don't mind if telecommunications equipment manufacturers also use those same unlicensed 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.  We will regulate, but not license. "

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)

3. Radiation levels inside the bands designated for ISM applications

3.1. Rationale  

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.

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, and to warn telecommunications equipment manufacturers about the need to provide interference immunity to their equipments.  Virtually nowhere in the world - except perhaps Hungary, which recently imposed rules to restrict ISM band usage to indoors only - 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.

  1. 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 original deal, in which case there should be "truth-in-advertising".  In that case, some intermediate position about ISM and 3.5 GHz can be worked out by all players involved, provided the consumers are enabled to get affordable, reliable, universal access and service.

The question one might ask is the following: why would anybody pay for a 3.5 GHz license when 2.4 GHz is free?  The answer has to do with allowable BANDWIDTH - the "transmission highway" is WIDER at 3.5 GHz band than at 2.4 GHz band (which in the West is already "congested" as the saying goes), 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 may be 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 banning use of 2.4 GHz ISPs is that equipment (modems, switches, routers, coders, decoders, etc.) in the 3.5 GHz range are far fewer than in the 2.4 GHz range - which 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.

Despite major strides in the telecommunications industry thanks to NCC's many proactive measures, this ISM band ban is one of those times when it is good to leave well enough alone.  We are still far from universal access to telecommunications, and that should be priority of the nation. 

A COMPROMISE ?

There are compromise ways of achieving results of promoting universal access of consumers, and protection of unlicensed and licensed users without banning 2.4 GHz.  Two of those include:

1.  limiting the power and hence the geographical range of 2.4 GHz equipments for ISP usage, and MANDATING the use of spread spectrum techniques (see Reference 2) such as Code Division Multiple Access (CDMA), which severely limit interference.  You can even increase the import tariffs on such equipment.

2.  providing incentives for 3.5 GHz operators, particularly in the rural areas where after all, 2.4 GHz is not common.  [Rural areas too are where the fear of interference or congestion is least.]  You can decrease the import tariffs on 3.5 GHz equipment intended for such use, and encourage the manufacture/assembly of 3.5 GHz equipment relative to 2.4 GHz.

Thus as a Christmas and New Year present, NCC should kindly lift the ISM band ban - and let the ISPs be.  We should mend the usage of 2.4 GHz by ISPs, not end it.

I rest my case.

Dr. Mobolaji E. Aluko is professor of Engineering at Howard University in Washington, DC, USA, and a member of the Implementation Task Force for NetTel@Africa (Nigeria) Program under the aegis of the Nigerian Communications Commission (NCC). He is also a member of the board of NITPA (Nigerian Information Technology Professionals in the Americas.).  He is President/CEO of Alondex Applied Technologies, LLC, a USA-based innovative technologies company. 

NOTES

Note 1:  Broadband - digital speeds greater than 264 kilobits per second (264 kbps) are generally considered broadband.  Speeds as high as 70 Megabits per second (70 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.  1 Hz = 1 cycle per second.

Note 4:  ADSL - Asymmetric 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.

REFERENCE

1.  ITU:  Frequently Asked Questions Related to Notification

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

2. "The ABCs of Spread Spectrum" by Randy Roberts

http://sss-mag.com/ss.html

BIBLIOGRAPHY

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

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

The ISM Frequency Band and Internet Service in Nigeria

Chineme Obuba

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

SUNDAY MUSINGS:  Resolving the interconnectivity battle in Nigeria -

Some suggestions" Mobolaji Aluko, November 16, 2003

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

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

 

Figure 1:  Simple Diagram of A Wave

 

Diagram showing the top of a wave is a crest, the 
bottom is a trough.

 

A chart showing the electromagnetic spectrum.

 

Figure 2: The uses of the electromagnetic spectrum.

 

 TABLE 1

ISM equipment in current use

 

Frequency

(MHz)

Major applications

RF power

(typical)

Estimated

No. in use

 

Below 0.15

Industrial induction heating (welding and melting of metals)

Ultrasonic cleaning (15-30 kHz)

Medical applications (ultrasonic diagnostic imaging)

 

10 kW-10 MW

 

20-1 000 W

100-1 000 W

 

> 100 000

 

> 100 000

> 10 000

 

0.15-1

Induction heating (heat treating, package sealing, welding and melting of metals)

Ultrasonic medical diagnostics

1 kW-1 MW

 

100-1 000 W

 

> 100 000

 

> 100 000

 

1-10

Surgical diathermy (1-10 MHz dampened wave oscillator)

Wood gluing and wood curing (3.2 and 6.5 MHz)

Valve induction generators production of semi-conductor material

RF arc stabilized welding (1-10 MHz dampened wave oscillator)

100-1 000 W

 

10 kW-1.5 MW

 

1-200 kW

2-10 kW

 

> 100 000

 

 

> 1 000

> 10 000

 

10-100

Dielectric heating (the majority operate on frequencies in the ISM bands at 13.56, 27.12 and 40.68 MHz, but many also operate on

frequencies outside the ISM bands)

- ceramics

- foundry core drying

- textile drying

- business products (books, paper, gluing and drying)

- food (post baking, meat and fish thawing)

- solvent drying

- wood drying and gluing (veneer and lumber drying)

-- general dielectric drying

-- plastic heating (die sealing and plastic embossing)

 

 

Medical applications

- medical diathermy (27 MHz)

- magnetic resonance imaging (10-100 MHz in large shielded rooms)

 

 

 

 

 

 

15-300 kW

15-300 kW

15-200 kW

5-25 kW

 

10-100 kW

 

5-400 kW

5-1 000 kW

 

1-50 kW

(most < 5 kW)

 

 

 

100-1 000 W

 

 

 

< 1 000

< 1 000

> 1 000

 

> 1 000

 

< 1 000

> 10 000

 

> 100 000

> 10 000

 

 

 

> 1 000

100-1 000

Food processing (915 MHz)

Medical applications (433 MHz)

RF plasma generators

Rubber vulcanization (915 MHz)

 

< 200 kW

< 1 000

 

< 1 000

Above 

1 000

RF plasma generators

Domestic microwave ovens (2 450 MHz)

Commercial microwave ovens (2 450 MHz)

Rubber vulcanization (2 450 MHz)

RF excited ultraviolet curing

 

600-1 500 W

1.5-200 kW

6-100 kW

 

> 200 million

< 1 000

 

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

 

TABLE 2

Range of measured levels of field strength from ISM equipment

in the ITU-designated ISM bands

 

 

 

 

Frequency band

 

Centre

frequency

Range of measured field

strengths

(dB(mV/m))(1)

 

     6.765-6.795 MHz

13.553-13.567 MHz

26.957-27.283 MHz

    40.66-40.70 MHz

433.05-434.79 MHz

          902-928 MHz(2)

    2,400-2,500 MHz

    5.725-5.825 GHz

    24.00-24.25 GHz

    61.00-61.50 GHz

          122-123 GHz

          244-246 GHz

 

    6.78 MHz

13.567 MHz

  27.12 MHz

  40.68 MHz

433.92 MHz

     915 MHz

  2,450 MHz

      5.8 GHz

24.125 GHz

  61.25 GHz

  122.5 GHz

     245 GHz

80-100

80-120

70-120

60-120

60-120

60-120

30-120

No information

No information

No information

No information

No information

 

 

(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)

Technology

(Max)

Speed

Mbit/s

Frequency

Range

Distance

Range

Notes

Wired (or Wireline)*

 

 

 

 

ADSL (G.dmt)

8

NA

Medium

Guaranteed bandwidth, uses splitter

ADSL (G.lite)

1.5

NA

Medium

Longer distances, slower

SHDSL

4.6

NA

Medium

Symmetric, fast

ADSL2

8

NA

Medium

No split, improved ADSL

ADSL2Plus

16

NA

Medium

Increased bandwidth of ADSL2

VDSL

52

NA

Short

High speed, short distances

Cable

30

NA

Long

Fast, shares capacity among users

Fibre

1000

NA

Long

Very high speed, optical

Wireless

 

 

 

 

IEEE 802.11b (Wi-Fi)

11

2.4 GHz

100 m

Most popular and widespread

IEEE 802.11a

54

5 GHz

50 m

Newer, faster, higher frequency

IEEE 802.11g

54

2.4 GHz

100 m

Fast, backwards compatible with Wi-Fi

IEEE 802.11e

54

 

NA

Adds QoS not present in a,b,or g.

IEEE 802.16a (WiMax)

70

2 - 11 GHz

50 km

QoS, Very long distance, Metro net

RadioLAN

10

5 GHz

35 m

Specializes in wireless bridges

HomeRF

1

2.4 GHz

50 m

Replaced by HomeRF2

HomeRF2

10

2.4 GHz

100 m

QoS, better encryption, not widespread

HiperLAN2

54

5 GHz

150 m

European standard, QoS, for voice/video

HiperMAN

NA

2 - 11 GHz

50 km

European, compatible with 802.16a

BlueTooth

1

2.4 GHz

10 m

Personal area network [not WLAN]

Infrared LAN

4

200 - 400 THz

20 m

Same room only

 

 

----- *see note 4

 


APPENDIX I

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)

The ITU Radiocommunication Assembly,

      Considering

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,

     noting

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,

   recommends

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 radiocommunications;

2. that there should be continued cooperation with the CISPR to ensure that radiocommunication needs are fully taken into consideration.

 

 

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