O'Reilly logo

Indoor Radio Planning: A Practical Guide for GSM, DCS, UMTS, HSPA and LTE, Second Edition by Morten Tolstrup

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

5.8 Co-existence Issues for GSM/UMTS

When deploying different radio systems and frequency bands using the same DAS for distribution, there are concerns that need special attention. You need to make sure that one system does not cause IM problems that will degrade the performance on its own or on other bands.

The problem rises exponentially with the power you feed to the DAS. The more power, the bigger the issue, mainly due to PIM (see Sections 4.3 and 5.7.3).

5.8.1 Spurious Emissions

A major source of co-existence problems is spurious emissions from the GSM transmitters (as shown in Figure 5.34). Therefore it is highly recommended always to use high-quality pass band filters on all transmitters, in a multioperator or multisystem DAS solution, when combining GSM and UMTS. Those filters will normally be a part of the base station, the combiner, but check the specifications of the base station to be sure.

Figure 5.34 Spurious emissions from a transmitter

img

Spurious emissions from GSM are restricted in the UL UMTS band (1920–1980 MHz) to a maximum img measured in 100 kHz bandwidth (equivalent to img in a 3.84 MHz channel). Any multioperator or multisystem DAS should be designed accordingly, in ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required