PIM Interference Analysis under Multi-band Multi-signal Input in Duplex Indoor Distribution System

This analysis focuses on PIM interference under multi-band multi-signal input in mobile communication system. Unlike single band system that only odd order PIM (especially 3rd order) should be concerned, in multi-band multi-signal case, both odd and even order PIM could be interference source because of more complicated intermodulation, more IMPS generated and more receive bands. Especially, the 2nd order PIM may interfere more serious to receiving channel for its strong magnitude. In duplex indoor distribute system, the PIM interference is a potential problem to GSM900, DCS1800, CDMA, and even 3G system wireless services, because the PIM frequencies may fall in receive bands and interfere to the receiving channels. In radio system design and wireless channel assignment, precautions must be taken to minimize the PIM level and to avoid interfere to receiving channels. For practical use, the lower order,possible PIM interference to 2G and 3G systems is calculated.