OFDM system with peak predistortion to reduce peak to average power ratio, wherein phase information is transmitted in pilot subcarriers

摘要

Phase distortions are applied to a multi-carrier signal at a transmitter to reduce PAPR. The receiver can reverse the phase distortions provided it knows the value of the phase distortion coefficient p . The receiver deduces the value of this coefficient by mathematically combining the phases of a plurality of pilot sub-carriers, preferably using equation 9. The pilot sub-carriers used for this purpose must be carefully selected to ensure that mathematical terms representing carrier frequency offset, W f, cancel, and terms representing sampling clock offset, h , also cancel. Consequently the pilot sub-carriers used for this purpose are non-evenly spaced. Carrier frequency offset and sampling clock offset can be deduced independently using a second set of pilot sub-carriers.