3GPP Requirements for Co-location

Co-location Deployment Considerations for Direct RF Sampling Transceivers (WP541)

Document ID
WP541
Release Date
2022-01-11
Revision
1.0 English
To make co-location deployment feasible, the 3GPP TSG RAN4 group has published additional requirements in the BTS radio specification [REF 1] for co-locating 5G radios. On the transmit direction, it specifies the maximum output power limit at each of the co-locating BTS bands in Table 6.6.5.2.4-1 for type 1-C and type 1-H 5G NR BTS. The following table is from [REF 1].
Note: Type 1-C is an NR base station operating at FR1 with a requirement set consisting only of conducted requirements defined at individual antenna connectors [REF 1]. Type 1-H is an NR base station operating at FR1 with a requirement set consisting of conducted requirements defined at individual transceiver arrary boundary (TAB) connectors and OTA requirements defined at RIB [REF 1].

The first ten wireless bands for co-location are listed in the table.

Table 1. TX Out-of-Band Power Limit for Co-location
Type of Co-located BS Freq. Range for Co-location Requirement Basic Limits Measurement Bandwidth
WA BS MR BS LA BS
GSM900 876-915 MHz –98 dBm –91 dBm –70 dBm 100 kHz
DCS1800 1710-1785 MHz –98 dBm –91 dBm –80 dBm 100 kHz
PCS1900 1850-1910 MHz –98 dBm –91 dBm –80 dBm 100 kHz
GSM850 or CDMA850 824-849 MHz –98 dBm –91 dBm –70 dBm 100 kHz
UTRA FDD band I or E-UTRA band 1 or NR band n1 1920-1980 MHz –96 dBm –91 dBm –88 dBm 100 kHz
UTRA FDD band II or E-UTRA band 2 or NR band n2 1850-1910 MHz –96 dBm –91 dBm –88 dBm 100 kHz
UTRA FDD band III or E-UTRA band 3 or NR band n3 1710-1785 MHz –96 dBm –91 dBm –88 dBm 100 kHz
UTRA FDD band IV or E-UTRA band 4 or NR band n4 1710-1755 MHz –96 dBm –91 dBm –88 dBm 100 kHz
UTRA FDD band V or E-UTRA band 5 or NR band n5 824-849 MHz –96 dBm –91 dBm –88 dBm 100 kHz
UTRA FDD band VI, XIX, or E-UTRA band 6, 19 830-845 MHz –96 dBm –91 dBm –88 dBm 100 kHz

For instance, if the 5GNR BTS is co-located with a wide-area base station operating in the PCS1900 band, then its transmitter output power must not exceed –98 dBm/100 kHz in the 1850 MHz to 1910 MHz frequency range at any time. This is the basic limit as indicated in the previous table. There are sub-clauses for mMIMO systems that have many antenna ports. On the receive direction, the 5G receiver must have the dynamic range specified in the following table [REF 1 Table 7.5.3-1]. Specifically, for a wide-area base station, it must be able to tolerate an out-of-band continuous wave (CW) signal at +16 dBm at the receiver connector without degrading its receiving sensitivity by more than 6 dB.

Note: The following table is taken directly from [REF 1] specification to illustrate the requirements.
Table 2. RX Out-of-Band Blocking for Co-location
Freq. Range of Interfering Signal Wanted Signal Mean Power (dBm) Interfering Signal Mean Power for WA BS (dBm) Interfering Signal Mean Power for MR BS (dBm) Interfering Signal Mean Power for LA BS (dBm) Type of Interfering Signal
Frequency range of co-located downlink operating band PREFSENS +6 dB 1 +16 +8 X 2 CW carrier
  1. PREFSENS depends on the BS channel bandwidth as specified in Table 7.2.2-1, 7.2.2-2, and 7.2.2-3 [REF 1].
  2. x = –7 dBm for NR BS co-located with Pico GSM850 or Pico CDMA850.

    x = –4 dBm for NR BS co-located with Pico DCS1800 or Pico PCS1900.

    x = –6 dBm for NR BS co-located with UTRA bands, E-UTRA bands, or NR bands.

  3. The requirement does not apply when the interfering signal falls within any of the supported uplink operating bands or in ΔfOOB immediately outside any of the supported uplink operating bands.
  4. For unsynchronized base stations (except in band n46 and n96), special co-location requirements might apply that are not covered by the 3GPP specifications.

While this is the 3GPP compliance specification, most network operators prefer that the 5G receiver sensitivity level does not get degraded at all. Along with the transmit direction, these specifications are much more stringent than without co-location.

In subsequent sections, the meaning of these co-location requirements are examined in terms of filtering needs and the implications on receiver architecture design to handle such high dynamic range. Specifically, a working example of the recently auctioned C band in the U.S. is analyzed, with a frequency range from 3700 MHz to 3980 MHz. It will be shown that these co-location requirements do not impose any significant additional filtering requirements when using direct RF sampling versus direct conversion transceivers (RFICs).