Frequency Ranges and Radio Licensing Regulations
5.1 Frequency Ranges Used
Frequency Ranges and Radio Licensing Regulations
5.1 Frequency Ranges Used
Because RFID systems generate and radiate electromagnetic waves, they are legally classified as radio systems. The function of otherradio services must under no circumstances be disrupted or impaired by the operation of RFID systems. It is particularly important to ensure that RFID systems do not interfere with nearby radio and television, mobile radio services (police, security services, industry), marine and aeronautical radio services and mobile telephones.
The need to exercise care with regard to other radio services significantly restricts the range of suitable operating frequencies available to an RFID system. During the RFID technology’s early days only internationally availableISM frequencies and the frequency range below 135 kHz could be used due to the nonassignment of separate frequencies. ISM stands for ‘Industrial Scientific and Medical’, i.e. for industrial, scientific and medical high-frequency applications. ISM frequencies are internationally reserved for applications using high-frequency devices. Examples are electrical discharge machines, microwave ovens or medical short-wave radiotherapy.
In addition to these applications, ISM frequencies can also be used for radio transmission. Due to the interference radiation inevitably caused by ‘actual’ ISM application, ISM frequencies of radio applications close to high-frequency devices are prone to interference. In our modern communication society, radio frequencies are a valuable commodity which should be used efficiently. Therefore it appeared sensible to reserve ISM frequencies for radio applications that are able to temporarily tolerate interferences and that have to bridge only short distances. The original idea was that anyone, including RFID applications, could use radio devices – without any costs and separate frequency allocation – on ISM frequencies (Bundesnetzagentur, n.d.). Today, ISM frequency bands are used by innumerable low-price radio installations (e.g. the 27 MHz, 433 MHz and 2.45 GHz range). It should always be taken into account that for a generous frequency usage it is not possible to ensure protection against interference.
Two classical ISM frequencies – 13.56 MHz and 2.45 GHz – are still used intensely for RFID systems today. Probably, the worldwide availability of these ISM frequencies and the possibility to use transponders and readers internationally without modifications in many countries has decisively contributed to the international triumph of RFID systems.
RFID Handbook: Fundamentals and Applications in Contactless Smart Cards, Radio Frequency Identification and Near-Field Communication, Third Edition. Klaus Finkenzeller
2010 John Wiley & Sons, Ltd
80
H, dBµA/m/10 m BC, LW-/MW-Navigation SW (Com., BC, Mobile, Marine...)
Non-ITU
ITU, not fully deployed FM Radio, Mobile Radio, TV
Microwave Link, SAT-TV
100−135 kHz 13.56 MHz 2.45 GHz
(< 30 MHz)
6.7813.56 27.125 40.66 433 868 915 2450 5800 MHz 24 GHz
Figure 5.1 The frequency ranges available for RFID systems range from the myriametric range below 135 kHz, through short wave and ultrashort wave to the microwave range, with the highest frequency being 24 GHz. In the frequency range above 135 kHz the ISM bands available worldwide are preferred
Due to the growing commercial importance of RFID systems and the increasingly liberal fre-quency regulation in Europe and other regions, from around the year 2000, new frefre-quency ranges for RFID systems have been created or the conditions for existing (ISM) frequencies have been improved. Thus, in Europe the frequency range between 865 and 868 MHz has been reserved for UHF backscatter systems. RFID systems with a field strength of up to 60 dBµA/m, measured at a distance of 10 m, can be operated on the classical ISM frequency 13.56 MHz. Other applications may only use 42 dBµA/m on this frequency. RFID systems are not generally classified as ISM appli-cations any longer, but are treated in Europe as a separate application of short-range devices (SRD).
Short-range devices are versatile devices for professional and private use, such as model remote controls, garage door openers, central locking systems, outdoor thermometers, motion detectors, avalanche transceivers, low-capacity radio devices for medical implants, article surveillance, Blue-tooth, vehicle identification for rail vehicles, traffic telematics and distance warning devices, radio motion sensors, alarm radio installations, inductive radio applications, wireless microphones, RFID systems, WLAN and many more.
The use of short-range device provides several advantages for the user: SRD frequencies are allocated for general public usage. This means that SRD use has neither to be registered nor autho-rized and no costs are associated to the use of these frequencies (Bundesnetzagentur, n.d.). Finally, SRD can be used in several European countries under the same conditions (see also Section 5.3.1).
In addition to ISM and SRD frequencies, the entirefrequency rangebelow 135 kHz (in North and South America and Japan<400 kHz) is also suitable, because it is possible to work with high mag-netic field strengths in this range, particularly when operating inductively coupled RFID systems.
The most important frequency ranges for RFID systems are therefore 0 –135 kHz, the classical ISM frequencies around 6.78 MHz, 13.56 MHz, 27.125 MHz, 40.68 MHz, 869.0 MHz, 2.45 GHz, 5.8 GHz and 24.125 GHz as well as the European SRD frequencies between 865 and 868 MHz (915 MHz in the US).
Low frequency (< 135 kHz)
High frequency (13.56 MHz)
UHF (868/915 MHz)
Microwave (2.45 GHz)
0 500 1000 1500
2000 2001 2002 2003 2004 2005
Figure 5.2 The estimated distribution of the global market for transponders over the various frequency ranges, in million transponder units (Krebs, n.d.)
An overview of the estimated distribution of RFID transponders at the various frequencies is shown in Figure 5.2.
5.1.1 Frequency Range 9–135 kHz
The range below 135 kHz is heavily used by other radio services. The propagation conditions in this long-wave frequency range permit the radio services that occupy this range to reach areas within a radius of over 1000 km continuously at a low technical cost. Typical radio services in this frequency range are aeronautical and marine navigational radio services (LORAN C, OMEGA, DECCA), time signal services, and standard frequency services, plus military radio services. Thus, in central Europe the time signal transmitter DCF 77 in Mainflingen can be found at around the frequency 77.5 kHz. An RFID system operating at this frequency would therefore cause the failure of all radio clocks within a radius of several hundred metres around a reader.
In order to prevent such collisions, the licensing regulations have defined several protected zones, e.g. between 70 and 119 kHz, with low field strengths which makes this range unattractive to RFID systems.
Wire-bound carrier systems also operate at the frequencies 100, 115 and 130. These include, for example, intercom systems that use the 220 V supply main as a transmission medium. The radio services permitted to operate in Germany within this frequency range are shown in Table 5.2. The actual frequency allocation, particularly in the range 119 –135 kHz, has fallen sharply. For example, the German weather service (DWD) changed the frequency of its weather fax transmissions to 134.2 kHz as early as mid-1996.
f(kHz) Class Location Call
110.5 FX Bad Vilbel DCF30
114.3 AL Stadtkyll –
117.4 FX Mainflingen DCF37
117.5 FX K¨onigswusterhausen DKQ5
122.5 DGPS Mainflingen DCF42
125.0 FX Mainflingen DCF45
126.7 AL Portens, LORAN-C, coastal navigation –
128.6 AL Zeven, DECCA, coastal navigation –
129.1 FX Mainflingen, EVU remote control transmitter DCF49
131.0 FC Kiel (military) DHJ57
131.4 FX Kiel (military) DHJ57
Abbreviations: AL air navigation radio service, FC mobile marine radio ser-vice, FX fixed aeronautical radio serser-vice, MS mobile marine radio serser-vice, NL marine navigation radio service, DGPS Differential Global Positioning System (correction data), Time signal transmitter for ‘radio clocks’.
5.1.2 Frequency Range 6.78 MHz (ISM)
The range 6.765 –6.795 MHz belongs to theshortwave frequencies. The propagation conditions in this frequency range only permit short ranges of up to a few 100 km in the daytime. During the night-time hours, transcontinental propagation is possible. This frequency range is used by a wide range of radio services, for example broadcasting, weather and aeronautical radio services and press agencies.
This range has been designated an ISM band by the international ITU and is being used in individual cases by RFID systems. CEPT/ERC and ETSI designate this range as a harmonised frequency in the CEPT/ERC 70 –03 regulation (see Section 5.3.1).
Table 5.2 Short- range device applications from REC 70-03 (Source: BAPT 1997)
Annex Application
Annex 1 Nonspecific short-range devices Annex 2 Devices for detecting avalanche victims Annex 3 Wideband data transmission systems Annex 4 Railway applications
Annex 5 Road transport and traffic telematics (RTTT)
Annex 6 Equipment for detecting movement and equipment for alert
Annex 7 Alarms
Annex 8 Model control
Annex 9 Inductive applications
Annex 10 Radio microphones
Annex 11 RFID
Annex 12 Wireless applications in healthcare Annex 13 Wireless audio applications
REC 70-03 also refers to the harmonised ETSI standards (e.g. EN 300 330), which contain measurement and testing guidelines for the licensing of radio devices.
5.1.3 Frequency Range 13.56 MHz (ISM, SRD)
The range 13.553 –13.567 MHz is located in the middle of the short-wavelength range. The propa-gation conditions in this frequency range permit (due to powerful shortwave transmitters) transcon-tinental connections throughout the day. This frequency range is used by a wide variety of radio services (Siebel, 1983), for example press agencies and telecommunications (PTP).
This range has been designated an ISM band by the international ITU. In directive CEPT/ERC REC 70-03, CEPT/ERC and ETSI designate this range as a harmonised frequency. Other ISM applications that operate in this frequency range are remote control systems, remote controlled models, demonstration radio equipment and pagers.
This frequency range is the one most frequently used for RFID systems (see also Figure 5.2).
The European regulations allows RFID systems on this frequency – as opposed to traditional ISM applications – to operate as SRD applications with a higher field strength (see Section 5.3.1.4).
5.1.4 Frequency Range 27.125 MHz (ISM)
The frequency range 26.565 –27.405 is allocated to CB radio across the entire European continent as well as in the USA and Canada. Unregistered and non-chargeable radio systems with transmit power up to 4 W permit radio communication between private participants over distances of up to 30 km.
The ISM range between 26.957 and 27.283 MHz is located approximately in the middle of the CB radio range. This range has been designated an ISM band by the international ITU. In directive CEPT/ERC REC 70-03, CEPT/ERC and ETSI designate this range as a harmonised frequency.
ISM applications operating in this frequency range include diathermic apparatus (medical appli-cation), high-frequency welding equipment (industrial appliappli-cation), remote controlled models and baby intercoms.
The most important RFID application in this frequency range is Eurobalise for transmitting placemarks and speed limits to rail vehicles (see Section 13.8.1).
When installing 27 MHz RFID systems for industrial applications, particular attention should be given to any high-frequency welding equipment that may be located in the vicinity. RF welding equipment generates high field strengths, which may interfere with the operation of RFID systems
(e.g. access systems), consideration should be given to any diathermic apparatus that may be present.
5.1.5 Frequency Range 40.680 MHz (ISM)
The range 40.660 –40.700 MHz is located at the lower end of the VHF range. The propagation of waves is limited to the ground wave, so damping due to buildings and other obstacles is less marked. The frequency ranges adjoining this ISM range are occupied by mobile commercial radio systems (forestry, motorway management) and by television broadcasting (VHF range I).
The main ISM applications that are operated in this range are telemetry (transmission of measur-ing data) and remote control applications. The author knows of no RFID systems operatmeasur-ing in this range, which can be attributed to the unsuitability of this frequency range for this type of system. The ranges that can be achieved with inductive coupling in this range are significantly lower than those that can be achieved at all the lower frequency ranges that are available, whereas the wavelengths of 7.5 m in this range are unsuitable for the construction of small and cheap backscatter transponders.
This range has been designated an ISM band by the international ITU. In directive CEPT/ERC REC 70-03, CEPT/ERC and ETSI designate this range as a harmonised frequency.
5.1.6 Frequency Range 433.920 MHz (ISM)
The frequency range 430.000 –440.000 MHz is allocated to amateur radio services worldwide.
Radio amateurs use this range for voice and data transmission and for communication via relay radio stations or home-built space satellites.
The propagation of waves in thisUHF frequency rangeoccurs approximately optically. A strong damping and reflection of incoming electromagnetic waves occurs when buildings and other obsta-cles are encountered. Depending upon the operating method and transmission power, systems used by radio amateurs can bridge distances of 30 –300 km.
The ISM range 433.050 –434.790 MHz is located approximately in the middle of the amateur radio band. This range has been designated an ISM band by the international ITU. In directive CEPT/ERC REC 70-03, CEPT/ERC and ETSI designate this range as a harmonised frequency.
This ISM band is extremely heavily occupied by a wide range of ISM applications. In addition to baby intercoms, mainly telemetry transmitters (including those for domestic applications, e.g.
wireless external thermometers), cordless headphones, unregistered LPD walkie-talkies for short-range radio, keyless entry systems (handheld transmitters for vehicle central locking) and many other applications are crammed into this frequency range. Unfortunately, mutual interference between the wide range of ISM applications is not uncommon in this frequency range. If possible RFID systems should avoid this frequency band and use the UHF frequency range instead.
5.1.7 UHF Frequency Range
The wave propagation in this UHF frequency range is quasi-optical. Buildings and other obstacles cause a strong dampening and reflection of the incident electromagnetic wave.
5.1.7.1 Frequency Range 865.0 MHz (SRD)
The frequency range 868 –870 MHz has been available for short-range devices (SRDs) in Europe since the end of 1997 and is thus available for RFID applications, even if only with low transmitting power.
In 2004 a new frequency range of 865 –868 MHz was introduced for RFID systems. It provides a substantially higher transmitting power. However, this frequency range is not yet really available in all 43 CEPT member states (see Section 5.3.1.5).
Neighbouring frequency ranges are occupied primarily by GSM telephones (GSM-900, e.g. the D network in Germany) and cordless telephones as described in the CT1+and CT2 standards.
5.1.7.2 Frequency Range 915.0 MHz
Outside Europe, various segments are available in the frequency range 860 –950 MHz: In North America between 902 –928 MHz (915 MHz), in Japan 950 –965 MHz, in Korea 910 –915 MHz, in Australia 918 –926 MHz, in South Africa 913 –915 MHz, and a range around 915 MHz in China (Clasenet al. 2005).
5.1.8 Frequency Range 2.45 GHz (ISM, SRD)
The ISM range 2.400 –2.4835 GHz partially overlaps with the frequency ranges used by amateur radio and radio location services. The propagation conditions for this UHF frequency range and the higher-frequency SHF range are quasi-optical. Buildings and other obstacles behave as good reflectors and damp an electromagnetic wave very strongly at transmission (passage).
Typical ISM applications that can be found in this frequency range are telemetry transmitters and PC LAN systems for the wireless networking of PCs.
This range has been designated an ISM band by the international ITU. In directive CEPT/ERC REC 70-03, CEPT/ERC and ETSI designate this range as a harmonised frequency. The European regulations allows RFID systems on this frequency – as opposed to traditional ISM applications – to operate as SRD applications with a higher transmitting power (see Section 5.3.1.5).
5.1.9 Frequency Range 5.8 GHz (ISM, SRD)
The ISM range 5.725 –5.875 GHz partially overlaps with the frequency ranges used by amateur radio and radio location services.
Typical ISM applications for this frequency range are movement sensors, which can be used as door openers (in shops and department stores), or contactless toilet flushing.
The most common RFID application in this frequency range is toll registration (RTTT, Road Transport andTraffic Telematics).
This range has been designated an ISM band by the international ITU. In directive CEPT/ERC REC 70-03, CEPT/ERC and ETSI designate this range as a harmonised frequency. The European regulations allows RFID systems on this frequency – as opposed to traditional ISM applications – to operate as SRD applications with a higher transmitting power (see Section 5.3.1.3).
5.1.10 Frequency Range 24.125 GHz
The ISM range 24.00 –24.25 GHz overlaps partially with the frequency ranges used by amateur radio and radio location services plus earth resources services via satellite.
Also this frequency range is used primarily by movement sensors, but also directional radio sys-tems for data transmission. The author knows of no RFID syssys-tems operating in this frequency range.