All digital compensation scheme for spur induced transmit self-jamming in multi-receiver RF frond-ends

In radio receivers employing diversity reception, receiver LO frequencies are closely separated. Different LO frequencies can couple through the substrate to the nonlinear components in the phase locked loops thus generating spurs. Such a spur, if it falls nearby the local transmit frequency, can inadvertently demodulate the strong local transmit signal and hence degrade the received SNR severely. In this paper, we investigate a novel method of compensating for transmitter self-jamming by carefully mimicking this mechanism in the received signal path and thus allowing cancellation. It has been shown that with certain simplifying assumptions one can realistically cancel the spur-induced transmit self-jamming interference. We outline the theoretical feasibility of this approach and then setup an RF test-bench to demonstrate these ideas on actual RF chipsets. Performance results from prototype measurements are reported.