Feasibility study on analogue cancellation of local interference in multimode transceivers

In multimode transceivers, the transmitter for one communication standard induces a strong local interference in the receiver for another standard. Such strong interference can severely affect the receiver, if it is not suppressed at an early stage of the receiver. A widely explored method to cancel a locally induced interference is to construct its replica, using an analogue model of the interference coupling path, and subtract it from the received signal. Performance of the cancellation method mainly depends on the model accuracy which is limited by the affordable complexity. This paper performs a feasibility study on the application of the cancellation in multimode transceivers based on a simulated scenario. In contrast to previous works, the presented analysis allows an easy comparison between variations of the cancellation method with different complexities. It is found that with a practical complexity the model is not sufficiently accurate. Thus only cancellation in a narrow band is attained. Moreover, the coupling of the local transmitter noise to the local receiver increases. A more accurate model can improve the cancellation; however, it is overly complex for mobile devices. This suggests the requirement for alternative methods to successfully mitigate the local interference.