Powerline telecommunications and the radio spectrum
The RSGB response to discussion with Ofcom and BIS
For over 10 years, the RSGB has been sounding warnings about the potential impact of PLT technologies on authorised radio services. PLT (Powerline Telecommunications) is a means of sending high speed data along mains electricity power lines. The mains wiring was never designed to carry such signals, and its inherent unsuitability to do so results in radio spectrum pollution which results in radio receivers not working as intended.
Initially the Society’s concern was the prospect of “Access PLT” being deployed. Access PLT brings broadband to the home via the electricity grid. Several national spectrum regulators, including the UK, were alert to the potential interference threat and made preparations to limit emissions from networks. The EU was in favour of promoting Access PLT as it saw the technology as a possible way of accelerating the penetration of broadband services to the home. The EU tried to block national regulators from bringing in their own controls in 2001 by issuing Mandate 313 to the standards bodies ETSI/CENELEC to produce an EMC Harmonised Standard to cover networks and apparatus. However, tests on this technology quickly showed that it was neither viable technically, nor commercially, and the trials in UK, US and Australia failed.
More recently the same technology has been deployed to produce “Powerline Adaptors” (PLAs)—which allow the user to send data between power sockets in the home. These products suffer from the same failing—radio spectrum pollution which causes significant disruption to radio reception in the area of the device. PLAs do nothing to increase the penetration of broadband into the home. They are simply a commodity device to provide an alternative to Wi?Fi or Ethernet in passing data from room to room in the home.
Governments have been slow to wake up to the threat from in-house PLT, which has been compounded in the UK by a change in the regulatory scene: spectrum regulation is now included in the wider?ranging remit of Ofcom, where broadband interests dominate. The result is an assertion that that there is not a significant problem. However, the reality is very different. The RSGB’s data suggests that, given the current market penetration of PLAs and the number of licensed amateur radio operators using the HF spectrum (that part of the radio spectrum most seriously affected by PLAs) the incidence of interference aligns closely with the probability of every PLA causing interference to a radio receiver in the vicinity. A recent Freedom of Information request confirmed that Ofcom was not aware of any PLT installations that did not cause spectrum pollution.
Radio pollution from devices such as PLAs are governed by European Directives and there is a relevant Standard. The current range of PLAs produce radio interference across a wide range of frequencies at a level some 1,000 times the maximum set out in the relevant technical standard. And yet the devices remain on the market, clearly flouting the letter and spirit of the EMC Directive and relevant standards.
Completion of Mandate 313 should have resulted in a Harmonised Standard use of which brings a “Presumption of Conformity” with the essential requirements of the EU EMC Directive.
However, after four years’ work, the joint efforts of ETSI and CENELEC failed to reach agreement. It proved impossible to reconcile the conflicting interests of PLT proponents and radio spectrum users. PLT users sought to legitimise significant “launch power” (the level at which broadband signals are injected onto power lines), whereas radio users recognised that such launch power would have a serious effect on radio reception, as a result of the levels of radio frequency emissions from such networks. Some commentators doubt whether such a Harmonised Standard could ever be effective for in?house PLT. Even if a home electrical circuit could be deemed a “network”, electrical cables were never intended to carry high speed data and in any case many dwellings have cabling that pre-dates the Directives. Furthermore, notwithstanding this, householders themselves would be expected to have carried out tests to show that their network conformed to the Essential Requirements of the Directive.
In the meantime CISPR, the World standards body which sets standards for controlling electromagnetic interference in electrical and electronic devices (which can cause interference to authorised radio services) had itself set up a task group to see if a standard could be produced covering PLAs. That work failed for much the same reasons as M313. Now the European Commission has tasked CENELEC with the task of producing a Harmonised Standard for PLAs, making clear that it expects a result to be produced quickly.
Whilst all this has been going on, sales of devices which clearly fail to meet the Essential Requirements of the EMC Directive, and relevant existing standards, have been permitted to continue. Documentation asserting conformity with the Essential Requirements has drawn on “Standards” which are no more than committee discussion papers (which in one case has been formally withdrawn) and national regulators, even in the face of clear evidence, have failed to exercise their statutory duty to protect the radio spectrum.
In the UK, the Spectrum Regulator (Ofcom) has been spectacularly ineffective in regulating the situation. Where interference has been reported, Ofcom has turned to BT (the UK provider of an IPTV product which is responsible for the dominant proportion of PLAs in the UK according to the PA report—see below) and BT has exchanged the offending devices for a more benign solution (Wi?Fi or wired Ethernet). This is tacit acceptance that the PLAs are non?conforming with the relevant Standards and Directives.
Now, however, PLAs are being sold over-the-counter to home computer users, to provide a form of “Ethernet” networking around the home. Ofcom does not know where these devices are installed, and so interference tracing becomes a much more difficult task.
At the same time, Ofcom commissioned a report from PA Consulting about the likelihood and probability of interference from PLT devices to radio services. The report did indeed confirm a high probability of interference, and recommended that effective mitigation measures be put in place to protect radio services. These measures centred on dynamically notching out the emissions from PLAs on frequencies used by certain radio services, and requiring PLAs to reduce launch power wherever possible. PA’s confidence in these mitigation measures however appears questionable, particularly in the light of its recommendation for permanent notches for safety critical service frequencies.
The RSGB has major concerns about the PA report, which in terms of its recommendations, is superficial and ill?informed. Dynamic power control and dynamic notching are at present theoretical concepts, only tested under quasi-“laboratory” conditions. When used in real world situations, with multiple PLA pairs in close proximity, their effectiveness in reducing interference to radio services will be much reduced. The RSGB asked Ofcom for a meeting with PA, to correct some of the misleading statements in the report, but Ofcom has refused this, saying that so far as they are concerned the PA work is complete.
The potential for significant interference to authorised radio services is beyond doubt, and yet Ofcom (whose role includes protection of the radio spectrum) has no powers today to take enforcement action against offending devices, where such action is deemed appropriate. In this, the RSGB believes that Ofcom is negligent.
The High Frequency radio spectrum is used for Broadcasting, Safety of Life, Military, Aviation and the Amateur Radio Service. With the exception of the Amateur Radio Service (whose frequencies are helpfully “notched” in PLT devices on the market in Europe to prevent unacceptable levels of interference, although this is a voluntary measure), all other frequencies are threatened by PLA devices. The RSGB has held meetings with Ofcom and BIS, arguing for restraint on the deployment of PLAs which cause so much damage to radio reception and the electromagnetic environment, but has been met with a less than helpful response. The following are statements made by Ofcom, BIS and the EU, and the RSGB’s response to them.
“There is no requirement to adhere to Standards”
This is true, but adherence to the Essential Requirements of the EMC Directive is an obligation on all products placed on the market. It is beyond belief that products that create emissions at 1,000 times the level of a Standard which brings the presumption of conformity with the EMC Directive, could be deemed compliant with its Essential Requirements.
“Ofcom is an evidence based regulator”
The RSGB accepts that Ofcom should rely on evidence to define its actions in radio spectrum regulation. However, when faced with the clear evidence (both technical tests, in-situ experience and the report commissioned by PA Consultants) Ofcom pleads inability (or unwillingness) to discharge its spectrum regulation duties.
“European regulations prevent action being taken which impact free movement of goods or services”
This is nonsense. The EC accepts that National Administrations have the right to take spectrum protection actions. The earlier work done in the UK, under the Wireless Telegraphy Act, to safeguard against potential access PLT interference was cleared in Brussels. WT Act Interference Regulations are proportionate, transparent and can only be deployed in actual cases of interference from systems in use (existing regulations provide protection against a wide range of electrical interference sources). There is simply no possibility that these could be used as a means to restrict trade. This argument is simply an excuse for inaction.
“Our actions need to be proportionate”
We are not seeking to ban a whole technology, however inappropriate PLT may be, but individual cases of interference must be resolved. It is beyond comprehension that an illegally certified device should be given priority over an authorised radio service.
“The EU’s stance is technology neutral ”
Exactly what this means is open to question. However, the EC is clearly not acting in a technologically neutral manner, by seeking to dramatically modify an existing standard to favour a specific technology. CISPR 22 / EN55022 has reasonably protected the radio spectrum from unwarranted interference for many decades. Simply because PLT devices cannot operate within the emission envelope of this standard is no reason to amend it, when such amendment would significantly impair authorised radio services. The EC’s mandate to CENELEC also seems to favour PLT over other technologies since it only applies to PLA devices.
“Mitigation measures through dynamic power control and dynamic notching will resolve the difficulties”
Again, another falsehood. In some very limited circumstances, these technologies might help. But they have not been tested in PLAs in a true multi-user field situation, and seem unlikely to be effective when faced with a plethora of other local PLT devices (as will be the case). To consider basing a Harmonised Standard on such unproven technologies is irresponsible.
“There have not been many complaints of interference”
Again, this does not truly reflect the position. In the UK, statistical modelling by RSGB shows a close alignment between the number of complaints and the market penetration of PLA devices, when mapped against the number of amateur radio operators using the high frequency spectrum. The Civil Aviation Authority and other Government users and broadcasters are also concerned about the threat from PLT. All appear to meet with deafness from the regulators.
“The new Standard being developed by CENELEC will resolve matters”
Developing a standard which legitimises the current levels of emissions from PLA devices will do nothing to improve the position. It will give the EC and national regulators an excuse for inaction, as conformance with a Standard brings a presumption of conformity with the EMC Directive. But simply moving the Standard to accommodate a polluting technology is both irresponsible and short?sighted.
The RSGB believes that the threat from PLT devices is simply not being taken seriously by many of the regulators. The sheer numbers of devices likely to be deployed over the next few years means that regulation of the radio spectrum is being ceded to the commercial interests of the PLT suppliers. It will not be possible to recover the damage done to the spectrum unless action is taken very quickly. The high frequency radio spectrum, an invaluable natural resource, is being consigned to history when a straightforward enforcement of relevant standards and directives would force PLA manufacturers to seek a cleaner technical solution.
The Clean Air Acts of 1956 and 1968 had a dramatic effect in improving the level of air pollution from factory chimneys and homes. Imagine the reaction nowadays if industrialists proposed creating new industrial processes which introduce pollution into the air at 1,000 times the relevant limits. That is what PLA devices do, and the resulting electronic smog will cause irreparable and permanent damage to the majority of the radio spectrum for years to come.
That is something the RSGB is determined to oppose.