MDEV-868-PRC datasheet(13/55 Pages) LINX

13 / 55 page

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Polite Spectrum Access

Europe’s ETSI standards have very specific requirements for operating in

the 868MHz band, which are contained in EN 300 220-1. One of the items

is called Polite Spectrum Access (PSA) and is a method of performing a

Clear Channel Assessment before transmitting to mitigate interference with

other systems.

The HUM-868-PRO employs Polite Spectrum Access. This allows the

module to exceed the 0.01% duty cycle limitation that otherwise applies

to modules operating in the 863-870MHz band. This is advantageous for

systems that need to transmit large data streams or have an unpredictable

usage pattern.

Systems that employ Polite Spectrum Access, while exempt from the

normal duty cycle restrictions, must meet channel occupancy time

requirements in ETSI EN 300 220-1 v3.1.1 section 5.21.3. The HUM-868

PRO module has a built-in mechanism that ensures compliance to this

requirement by internally limiting each channel’s cumulative on time. This

limits the transmission time on any given channel to 33.3 seconds per hour.

The module uses 70 channels so it can transmit for 2,333s of every hour or

about 64% assuming no delay for transmissions by other units.

It is preferable to spread the transmit time out evenly to avoid using all of

the time at the start of the hour and then having 21 minutes’ delay at the

end of the hour. To accomplish this, the module divides the time into blocks

of 180s called bandspread intervals. The module can transmit on each

channel for 1.66s of every 180s (33.3s of every 3600s ÷ 20).

The PSA options are configured with the ENCSMA register. Setting the

be used in applications with an inherent duty cycle <0.1%.

Setting the register to 0x01 enables LBT but without the transmitter on time

duty cycle restriction.

Setting the register to 0x02 enables the full LBT with transmitter on time

restriction. This complies with the ETSI regulations for LBT + AFA.

Leaving the register in its default value of 0x02 enables Polite Spectrum

Access. To maintain validity of the HUM-868-PRO module Declaration of

Conformity (DoC) this setting (0x02) must be used and must not be user

adjustable.

ETSI Compliance

The HumPRC™ Series module has been tested and conforms to

requirements of the current Radio Equipment Directive (RED) standards.

The module’s test report and Declaration of Conformity (DoC) are available

from Linx Technologies upon request. Linx Technologies Reference Guide

RG-00111 outlines the test setup and radio configurations that were used

in the testing and certification of this device.

Designs that incorporate the module as it was tested in RG-00111 may

utilize portions of our test data in their application. For those designs that

differ, please contact Linx Technologies for certification assistance and

advice.

Note: The integrator is solely responsible for ensuring that the final

product complies with CE / ETSI requirements. This includes all testing

and any application specific requirements.

MDEV-868-PRC Datasheet(PDF) 13 Page - Linx Technologies

MDEV-868-PRC Datasheet(HTML) 13 Page - Linx Technologies

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