An adaptive cancellation system for a colocated receiver and its dynamic range

Wireless communication service providers are having to co-locate base stations (BTS) on common sites, since little space is available to build new ones. BTS receivers have to receive weak desired signals at the presence of strong transmit signals from co-located transmitters; resulting in interference and desensitization. This leads to higher dynamic range requirements for BTS receivers. The paper describes an adaptive cancellation system for mitigating these large transmit interferers at a BTS receiver; hence, increasing the receiver´s dynamic range. The paper further derives theoretical expressions for the IP3 and noise factor, which formulates the upper and lower end of the dynamic range of the system. Practical measurements demonstrate a reduction in interference and intermodulation. The prototype achieves a cancellation of 53dB.