The Various steps to control inter-system interference include:
1. external Filters, add the transmitters and receivers
2. Antenna isolation between transmitters and receivers of victims
3. the distance between transmitters and receivers of victims
4. Reduce transmission power
5. Guard band between operators
Step 1 is probably the most common technical solutions. This can have a much greater effect isolation to the DB than steps 3 and 4 and does not require as much coordination between operators as steps 2 and 3. However, you may create a filter of time and cost significant problems. And achieve the benefits of filters normally require step 5, guard the group, in addition to the filters.
Step 2 can have large positive effects. This can be done simply by gradually downtilt antenna to increase the base station. However, in other cases it may be necessary to extensive coordination between operators.
Step 3 usually has less effect than the 1 or 2 and can create problems of coordination Similar to step 2.
Step 4 is usually relatively modest improvements, but can provide quick results. 1 DB transmission power reduction may give three dB reduction in OOBE (out of band emissions), in the immediate adjacent channels because the OOBE close usually comes from transmit power amplifier third order intermod. However, the transmitter operator can should trade reducing cover for better coexistence with other operators.
Step 5 may be enough in itself to reduce the OOBE, and in the case of a blocking receiver.
However, in some cases, bands have little or no effect. For difficult situations the greatest benefits derive from the use of filters, along with guard bands.