Data processing apparatus and method

摘要

To reduce the peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplexed (OFDM) based communications system, a transmitter applies a unitary matrix transformation 340 to modulated symbols corresponding to input data streams 320 before the transformation of the symbols by an inverse Fast Fourier Transformation (IFFT) algorithm 308. Pilot symbols are inserted using a multiplexer 342 prior to the IFFT processing. In another embodiment (figure 4A) the pilot symbols also undergo a unitary matrix transformation prior to insertion. In further embodiments supplementary post-IFFT PAPR reduction techniques are applied, for example, active constellation extension (ACE) or tone reservation (TR) algorithms (see figures 6A and 7A). Corresponding receiver arrangements are also disclosed.