Co-existence of GSM1800 and GSM1900: BTS-to- BTS interference

Co-existence of GSM1800 and GSM1900 that share the same frequency band is becoming one of significant problems and the most challenging issues. The most critical co-existence situations occur when the downlink of any system is close to the uplink of the concerned GSM system. In that case one base transceiver station (BTS) is constantly disturbing a GSM BTS probably with high gain antennas on both sides. The scope of this paper is to study the co-existence interference issues, which may occur when operating GSM1800 system with GSM1900 system within the same geographical area, and give recommendations to avoid them. Minimum separation distances to avoid the impact of GSM1800 DL to GSM1900 UL interference are recommended in this paper.