Handling Unlikely Sources of Interference in Marinas

The Situation

A mobile operator in the 850MHz UMTS B-Band was challenged by watercraft of all sizes utilizing bi-directional amplifiers (BDA's) for communication system signals. These devices created unwanted interference throughout the carrier's coastal cell sites. Large vessels would dock for a period of time and monopolize these BDAs. Additional interferers include analog devices (security devices, television amplifier devices, etc), and other local RF sources that are not properly filtered or optimized.

These interferers created a double whammy - an increase in the noise floor and additional mobile transmit power resulting in higher dropped call rates and incomplete call attempts. The net result is that quality of service was impacted resulting in higher rates of customer complaints.

The Resolution

ISCO provided its spectrum conditioning units for an evaluation to solve the interference issues. Initially, activities included an evaluation of the spectrum conditioning units working with the Ericsson BTS to "notch" out interferers in a lab environment. The tests were successful.

The next step was to place the spectrum conditioning units into one of the sites for a live trial. The resolution of the problem was immediately seen. There were multiple interferers, large and small, and the spectrum conditioning units immediately applied notches to mitigate the interference. The ISCO spectrum conditioning units can apply up to three notches simultaneously.

Infrastructure Details

The spectrum conditioning units are designed to be installed into networks experiencing in-band and co-channel interference and using various BTS's from different equipment manufacturers; ISCO has a special installation kit for each vendor's BTS.Once installed, ISCO can demonstrate successful interference mitigation as shown below. Click on an image for larger view.