Remote Control of Private Business Systems Using Licence Exempt Low Power Devices Type Approved to and Compliant with ETS 300 328

Purpose of this Information Sheet

1 This information sheet outlines a method of remote control for Private Business Systems using Low Power devices, which can be used as a possible method of control under the terms of an appropriate Private Business Radio (PBR) Licence.

Background

2 Some PBR licensees locate their base station remotely from the normal business location or office (control point) for ease of operation, or indeed to improve coverage area by gaining greater height for the base antenna. In some cases it is impractical or uneconomical to install the normal wire connections required to connect the control point to the base unit.

3 Various other options such as landlines rented from network operators on a permanent basis, or a dial up landline facility can be used to connect the control point and base unit together, however these solutions may require financial expenditure in the form of a quarterly rental fee. Other options such as Reverse Frequency Working can provide an alternative solution. Wide Band data equipment operating in the 2.4 GHz frequency band can offer another viable alternative for base station control. This type of equipment is also widely known as RLAN (radio local area network) equipment

Data Transmission Systems

4 Wideband radio data transmission systems are rapidly being introduced into a variety of commercial and industrial applications, the technology employed by these systems is still developing. For some data type systems a possible alternative method of remote control can be provided by using a low power licence exempt device, type approved to and compliant with the European Telecommunications Standard ( ETS ) 300 328. This standard is titled

Wideband data systems for data transmission operating in the 2.4 GHz Industrial Scientific and Medical (ISM) band using spread spectrum modulation techniques.

5 Use of this remote control facility must meet the conditions laid out in ETS 300 328 and the relevant EMC standard. These include:-

Adoption of wideband radio modulation techniques using aggregate bit rates in excess of 250 kbits per second;

Operation conducted in the 2.4 to 2.4835 GHz Industrial, Scientific and Medical (ISM) band;

Effective isotropic radiated power (defined as the total power of the transmitter) shall be equal to or less than 100 mW erp.

For frequency hopping modulation the power density may be up to 100 mW per 100 kHz. For other forms of spread spectrum modulation, power density of up to 10 mW per 1 Mhz is permitted.

Frequency Hopping Spread Spectrum (FHSS) modulation shall make use of at least 20 well defined, non-overlapping channels or hopping positions separated by the channel bandwidth as measured at 20 dB below peak power. Dwell time per channel shall not exceed 0.4 seconds. While the equipment is operating (transmitting and/or receiving) each channel of the hopping sequence shall be occupied at least once, during a period not exceeding four times the product of the dwell time per hop and the number of channels. Systems that meet these constraints shall be tested according to the requirements for FHSS modulation.

Frequency Range

6 The frequency range of the equipment is determined by the lowest and highest frequencies occupied by the power envelope.
The highest frequency (fH) of the power envelope, is the frequency furthest above the frequency of maximum power, where the output power drops below the level of - 80 dBm/Hz spectral power density, 30 dBm if measured in a 100 kHz bandwidth. The lowest frequency (fL) of the power envelope, is the frequency furthest below the frequency of maximum power, where the output power drops below the level of - 80 dBm/Hz spectral power density, 30 dBm if measured in a 100 kHz bandwidth).

The width of the power envelope is fH - fL for a given operating frequency.

7 In equipment that allows adjustment or selection of different operating frequencies, the power envelope takes up different positions in the allocated band. The frequency range is determined by the lowest value of fL, and the highest value of fH, resulting from the adjustment of the equipment to the lowest and highest operating frequencies. For all equipment the frequency range shall lie within the band 2.4 GHz to 2.4835 GHz (i.e. fL > 2.4 GHz and fH < 2.4835 GHz).

How to apply for this method of control

8 Licensees wishing to adopt this method of control can request an amendment to their existing licence to permit such use on form RA1A. New licensees requiring this facility should request this method of control in their initial application on form RA1. If acceptable to the Agency, this method of control will subsequently be detailed on the PBR licence as the type of remote control to be utilised.

Interference

9 The Agency will not investigate any complaints received from licensees suffering interference to their system, as a result of using this facility as a method of remote control. Consequently licensees may wish to consider other suitable methods of control such as RFW, for which the Agency will offer a level of interference protection. The Agency cannot advise which method is most suitable for particular licensee's circumstances. This must remain a business decision for the licensee in consultation with their equipment supplier.

Existing low power devices for control of PBR systems

10 Some licensees, mainly users of nationally exclusive channels, have previously been permitted to use alternative types of low power device in various licence exempt bands as methods of controlling PBR systems. The continued use of existing systems
will be permitted on a non-protected non-interference basis. All spread spectrum equipment installed for operation in the band 2400-2483.5 Mhz for remote control of PBR equipment must adopt the ETS 300 328 equipment standard.

Further information

11 Further information on this subject may be obtained by contacting the Agency's Library and information services on
020 7211 0502.

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