What is the difference between co-located BTS and co-existed BTS and explain the required 3GPP compliance
Co-existence with other systems
The manufacturer shall declare whether the BS under test is intended to operate in geographic areas where one or more of the systems GSM850, GSM900, DCS1800, PCS1900, UTRA FDD, UTRA TDD, E-UTRA and/or PHS operating in another band are deployed.
The limits may apply as an optional protection of such systems that are deployed in the same geographical area as the E-UTRA BS, or they may be set by local or regional regulation as a mandatory requirement for an E-UTRA operating band.
Some requirements may apply for the protection of specific equipment (UE, MS and/or BS) or equipment operating in specific systems (GSM, CDMA, UTRA, E-UTRA, etc.). The power of any spurious emission shall not exceed the limits as define in 3GPP 36.104 or 36.141.
In case of Co-existence, BTS compliance is to be done for spurious emissions and few of these spurious limits are shown below:
Here if co-existed base station is suppose GSM900, then power transmitted in the frequency from 921 to 960MHz shall be below -57dBm (measurement BW 100KHz).
Co-location with other base stations
The manufacturer shall declare whether the BS under test is intended to operate co-located with base stations of one or more of the systems GSM850, GSM900, DCS1800, PCS1900, UTRA FDD, UTRA TDD and/or E-UTRA operating in another band. Co-located means on the same site or tower.
In case of Co-location, BTS should be compliant as follows:
– compliance with the applicable test requirement for spurious emissions
– compliance with the applicable test requirement for receiver blocking
In case of Co-location, BTS spurious compliance specifications as shown in below example:
And Blocking (In-band and out of band blocking) is a receiver test, which also need to be tested as per 3GPP compliance.
Co-location compliance is more stringent because in this case, the victim BTS is mounted at the same site and that is too close to aggressor BTS.
Co-located BTS means another band BTS placed on the same site/tower on the other hand co-existed means in the same geographical area, not on the same site/tower.