Spectral efficiency enhancements utilizing analog RF frontend in-band interference cancellation

Abstract

Today's radios operate invariably in half duple) mode, i.e., they can either transmit or receive, but not both simultaneously in the same frequency band. The inability to simultaneously transmit and receive inherently reduces the spectral efficiency of a radio channel by 50%. Spectrum scarcity and souped-up demand for data from the smar devices, the wireless networks have been unable to cope with the growing needs of the user community. The realization of the full duplex mode operation in the prevailing circumstance has attracted a lot of attention from both industry and academia. The fundamental obstacle in achieving the ful duplex mode operation emanates from the self-induced interference from its own transmitted signal, which interfere with the received Signal of Interest (SoI). Majority of wireles communication systems operate in half duplex mode (inheren inefficiency) to avoid self-interference and to preven desensitizes of their receive chain. The key challenge in achieving the full-duplex radio operation in the same frequency band originates from the huge power differentia between transmitted power and the received signal of interest arriving from a faraway transmitter as well as the nonlinearity of the Radio Frequency Front End (RFFE) transmit/receive components. This large power differential saturates the Low Noise Amplifiers (LNA) and overwhelms the dynamic range o the Analog to Digital Converter (ADC) in the receive chain raising the Receive (Rx) noise floor to an undesirably high level. Many analog and digital cancellation techniques have been proposed and implemented with limited success in specific environments. A more generic technique, which allow for adaptive cancellation of interference from various source in dynamic environment, has been studied, implemented, and the result has been documented in this paper.