CDMA mobile station intermodulation interference induced by AMPS competitor base station

This paper derives a theoretical mobile intermodulation (MIM) interference prediction model based on the TIA/EIA IS-98 specification. Even though interference between different cellular carriers is theoretically minimized by allocating a partitioned and dedicated spectrum to each operator, an interference problem occurs in practice when the mobile station comes within close vicinity of high effective radiated power (ERP) competitor cell sites. This interference is due to the strong third-order intermodulation products generated by the mobile station receiver, which produce co-channel interfering signals in the server´s spectrum. This paper confirms the accuracy of the theoretical prediction model with a series of measurements. Additionally, we suggest two methods of minimize the MIM interference in this paper (one is inserting a band pass filter (BPF) with 10 MHz 3 dB bandwidth in front of the low noise amplifier (LNA) and the other switching it off)