Co-location, Isolations

Spurious emissions are emissions, which are caused by unwanted transmitter effects such as harmonics emission, parasitic emission, intermodulation products and frequency conversion products, but exclude out of band emissions. This is measured at the base station RF output port.

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Spectrum Emission Mask, 3GPP TS 25.104 Fig. 6.2

Spurious emissions limits for protection of the BS receiver

The table above corresponds to -80 dBm / 3.84MHz spurious emission requirements from UMTS DL to UMTS UL.

EXAMPLE

Spurious emission DL to UL	- 80 dBm	See above
Max sensitivity degradation	- 121 dBm	BS reference sensitivity
Min required isolation	41 dB

UMTS FDD isolation requirement due to spurious emissions

Note: Check with your vendor, they will quote a lower figure

The receiver blocking characteristics is a measure of the receiver ability to receive a wanted signal at its assigned channel frequency in the presence of an unwanted interferer on frequencies other than those of the adjacent channels.

EXAMPLE

Max Node B power	43 dBm	= 20W
Blocking level	- 40 dBm	3GPP 25104 7.5.1
Min required isolation	83 dB

UMTS FDD - FDD isolation requirement due to receiver blocking

Note: Check with your vendor, they will quote a lower figure

The transmit intermodulation performance is a measure of the capability of the transmitter to inhibit the generation of signals in its non linear elements caused by presence of the wanted signal and an interfering signal reaching the transmitter via the antenna. The transmit intermodulation level shall not exceed the out of band emission or the spurious emission requirements.


Summary: Co-location and isolation related issues

Co-location issues; base station receivers; spurious emission and blocking Co-existence issues; mobile phone receivers; spurious emission and blocking Intermodulation issues All wireless systems need to be considered Vendor equipment specification far better that 3GPP specifications Solution considerations Equipment specifications Horisontal antenna separation Vertical antenna separation Additional filtering Antenna beamwidth Antenna bearing Frequency coordination with other carriers Smart designs for common antenna systems