Full steam ahead for SRDS and RFID at UHF
Short range devices with a long reach
As the seemingly insatiable appetite for spectrum for wireless broadband continues apace, supported by
the European Union’s spectrum policy programme which calls for 1200 MHz to be made available, we take
a contrasting look at why some of our more moderate spectrum users are also ripe for growth. A wide
range of highly valuable uses of spectrum are to be found squeezed into a few relatively narrow bands
operating as (typically unlicensed) Short Range Devices (SRD). These devices have a huge significance in our
daily lives, whether as assistance for people with a hearing impairment, or bringing down the costs of
supermarket goods, or as part of making an intruder alarm system affordable, to give just three examples.
Europe (CEPT, the European Conference of Postal and Telecommunication Administrations) is working to
improve the efficiency of these bands and widen the possibilities for accessing them. This is based on
applying a step-by-step evidence-based process for enabling more generic conditions to be applied to wider
spectrum bands than before, instead of slicing the available frequencies into narrow bandwidths for niche
applications.
Now, a major milestone, driven by demand
Now the CEPT in Europe has reached a major milestone in the development and management of
frequencies in the favoured range just below 1 GHz for a wide variety of SRDs applications with the creation
of a new roadmap which paves the way for a major upgrade of 19 MHz of spectrum. At present the range
863 to 870 MHz is used extensively for SRDs. However, these ranges are filling up quickly and a lot of new
developments are anticipated, as by ECC Report 182 (Survey about the use of the frequency band 863-870
MHz) and ETSI1 in a set of System Reference Documents. This includes rising spectrum demands for generic
SRD, UHF RFID, Home Automation & Sub Metering, automotive SRD, Smart Meters and Smart Grids,
Metropolitan Mesh Machine Networks (M3N) applications, Alarm and Social Alarm systems, and Assistive
Listening Devices (including hearing aids). In addition to capacity constraints, the bandwidth of the existing
plans is limiting to developing applications, e.g. a wider bandwidth for individual RFID devices will improve
their performance and function. With machine mesh networks, the required bandwidth of the systems
would not fit into the existing narrow bandwidths that are available.
Against this background, we need to take account of two significant considerations. Firstly, in the American
continent nearby frequencies (902 to 928 MHz) are allocated to ISM2, which is a convenient basis for using
SRDs, and therefore a lot of equipment is being developed to operate in this range. For Europe, as part of
the ITU-R Region 1, no ISM band was identified at the World Administrative Radio Conference (WARC-79) in
1979 in this part of the spectrum. This new SRD harmonisation measure (together with the DSI3
harmonisation effort about ten years ago in Europe) is for practical purposes a Europe-specific review of
that decision made 34 years ago. Secondly, there are two significant adjacent frequency ranges which are
seriously under-utilised in many countries: namely 870 - 876 MHz, and 915 - 921 MHz; these are
1
The European Telecommunication Standards Institute published five system reference documents: Generic SRD,
RFID, Home Automation & Sub Metering and Automotive SRD, TR 102-649-2; Smart Meters and Smart Grids, TR 102
886 ; Metropolitan Mesh Machine Networks (M3N) applications, TR 103 055; Alarm and Social Alarm systems, TR 103
056 and Assistive Listening Devices, TR 102 791.
2
Industrial, Scientific and Medical uses.
3
Detailed Spectrum Investigation, a three-phase thorough review of the European plan for allocation of frequencies.
frequencies which had been prepared for use by private mobile radio systems, but that development has
seen very little take-up.
With the rapid growth in applications for both SRDs and RFID, the industry had recognised that there was
an urgent need for additional spectrum at UHF. They identified that the dual band 870-876 MHz and 915921MHz, which had originally been allocated to PMR/PAMR e.g.(TETRA), was effectively unused. In their
SRDocs to CEPT, ETSI proposed that the band 870-876 MHz be assigned to SRDs. WGFM have agreed that
the band will be predominantly occupied by SRDs at 25 mW and a D.C of up to 1% in bands of up to 600
kHz. However some vehicle applications are permitted to operate at up to 500 mW at a DC of 0.1%. Also
Metropolitan Area Networks may also operate at power levels of 500 mW with a DC up to 10% for their
Network Relay Points. However these may be subject to individual licenses.
The upper band will be occupied by RFID with interrogators operating at power levels up 4W e.r.p. in 4
channels of 400 kHz equally spaced at 1.2 MHz. Tags should respond in the low power channels not used by
the interrogators. SRDs (at up to 100 mW and 1% D.C) and assisted listening devices (at 10 mW and 25%
D.C) are permitted to share the high power interrogator channels with RFID. SRDs are permitted to occupy
the low power channels at duty cycles of less than 1% and power levels not exceeding 25 mW.
The availability of this additional spectrum will bring considerable benefits. In the case of SRDS it will
provide an opportunity to introduce some important new applications such as smart metering and new
uses in the automotive industry. More importantly it will provide the additional capacity necessary for the
continued expansion of traditional applications such as home automation, alarms, telemetry and general
purpose SRDS.
For RFID the principal benefits will be the ability to operate at higher power and faster data rates. It will
allow RFID to meet the needs of new applications where previously this had not been possible. A further
important benefit is that RFID will be able to operate in the same band as used by all of the other major
trading nations.
ECC instruments and conclusions
ECC Report 200 gives the background and conclusions to a comprehensive set of coexistence studies in
these under-utilised UHF bands in Europe. Some of these used the ECC’s SEAMCAT analysis tool, developed
and maintained by the ECO in Copenhagen. The related ECC Report 189 prepared by the ECC’s SRD
Maintenance Group, used these conclusions to define recommended regulatory parameters for SRDs.
Finally Recommendation 70-03 was agreed in February 2014 with new entries in the 870-876/915-921 MHz
frequency bands. Report 189 recognises that although under-utilised for Professional Mobile Radio (PMR),
there are significant existing governmental services with access to part of the new frequencies in several
countries which would need protection in the future at the discretion of the relevant national
administrations. The review included an audit of these existing and planned uses, which revealed not only
some of the military tactical systems as known about, but also some new uses such as remote control of
unmanned aircraft (UAV). Some other countries anticipate needing to use the spectrum in some specific
locations for an extension of the existing GSM-R bands. The studies in the ECC have covered this utilisation
to provide a solution for spectrum sharing with GSM-R.
870-876 MHz band plan:
500 mW (with APC), ≤200 kHz Up to 2.5% DC Metropolitan/Rural Area Networks.
Up to 10% DC for Network Relay Points
(subject to individual license)(ERC Rec 70-03 Annex 2)
500 mW (with APC), ≤500 kHz, 0.1 % DC TTT Vehicle to Vehicle only (ERC Rec 70-03 Annex 5)
100 mW (with APC) 0.1% DC TTT in vehicle only (ERC Rec 70-03 Annex 5)
25mW 1% DC ≤600 kHz (ERC Rec 70-03 Annex 1)
25mW 0.1% DC ≤200 kHz (ERC Rec 70-03 Annex 1)
SRD
R- SM
ER- SM 7 - 76 MHz
875.6
MHz
870
MHz
875.8
MHz
876
MHZ
915-921 MHz band plan:
CF 916.3 MHz
200 kHz of low
DC safe haven
RFID tag return
RFID
@
4W
SRD
100
mW
1%
DC
ALD
10
mW.
25%
DC
Per
chan
nel
CF 917.5 MHz
RFID tag return
RFID
@
4W
SRD
100
mW
1%
DC
ALD
10
mW.
25%
DC
Per
chan
nel
CF 918.7 MHz
RFID tag return
RFID
@
4W
SRD
100
mW
1%
DC
ALD
10
mW.
25%
DC
Per
chan
nel
CF 919.9 MHz
RFID tag return
RFID
@
4W
SRD
100
mW
1%
DC
ALD
10
mW.
25%
DC
Per
chan
nel
RFID tag return
200 kHz Low DC
safe haven
25 mW 1% DC Per 600 kHz channel. Channel bandwidth ≤ 600 kHz
25 mW 0.1% DC Per 200 kHz channel. Channel bandwidth ≤ 200 kHz
ER- SM (base stations
1 - 21 MHz
SM mobile
915MHz 915.3
MHz
916.1
MHz
916.5
MHz
917.3
MHz
917.7
MHz
918.5
MHz
918.9
MHz
919.7
MHz
920.1
MHz
R- SM
920.9
MHz
921 MHZ
ECC Report 200 also describes the use of network access points/network relay points forming part of
metropolitan area ‘mesh’ networks such as for utilities or other applications for the purpose of data
acquisition.
This particular approach provides a good example of the CEPT use of ‘soft harmonisation’, where existing
services remain protected to the extent that national administrations deem it necessary, yet providing the
opportunity for the harmonised development of new services in the majority of European countries. The
success of the ERC Recommendation 70-0 owes much to its ‘soft harmonisation’ approach, which is
quicker to set up than a more rigid, centralised harmonisation process, where the measures needed to deal
with important but limited incumbent interest can block or delay the process at the European level.
As a result of the decision by CEPT to make additional spectrum available, ETSI will introduce revisions to
the standards EN 300 220 for SRDs and EN 302 208 for UHF RFIDs. It is hoped that the new versions of the
standards will become available during 2015.
Based on a CEPT initiative, there was also recently a decision at the ITU-R WP1B in Geneva to hold an ITU-R
SG1 workshop on 3 June 2014 on further SRD regional and global harmonisation possibilities, following
Resolution 54 of the ITU-R, and the developments in UHF for SRDs and RFIDs may certainly be an issue in
the future for amended harmonisation around the globe.
By Thomas Weber, ECO Spectrum Management and Chairman of the SRD Maintenance Group