Design of low-complexity scheme for maintaining distortion-free multi-carrier communications

This study describes a scheme which enables one to improve the quality of one´s own wireless communications, over a given frequency (or frequencies), when in the presence of inter-modulation distortion (IMD). The IMD is generated by one´s own power amplifier (PA), when operating over an adjacent band of frequencies, and arises as a result of the non-linear nature of the PA when engaged in the transmission of modulated multi-carrier signals. The distortion appears in the form of inter-modulation products (IMPs), these occurring at multiple frequencies which may potentially coincide with one´s communication frequency. The scheme enables one to predict the frequency locations and strengths of the IMPs and, when coincident with the communication frequency, to clear the IMPs from that frequency regardless of the levels of distortion present. The speed at which the IMPs are identified and cleared from the communication frequency - attributable to the efficient exploitation of polynomial arithmetic/algebraic techniques and a fast Fourier transform routine - offers the promise of maintaining reliable communications without having to interrupt the operation of one´s own electronic equipment. The low complexity also offers the possibility of an attractive hardware solution with a low size, weight and power requirement.