An Interference Cancellation Technique for the Use in Multiband Software Radio Frontend Design

A fundamental step towards the design of multiband radios is the replacement of fixed frequency components, like duplexers. For solving the arising problems we started with the development of an analog frontend incorporating a technique to suppress one of the main interference effects, namely the coupling of the transmitted signal into the receiving path. This has been accomplished using an active cancellation technique built into a wideband demonstrator operating in the frequency range from 800 to 2200 MHz and for radio channel bandwidths up to 5 MHz. Using the proposed cancellation technique we achieved a total interference suppression of up to 60 dB.