| Orthogonal Frequency Division Multiplexing (OFDM) has, in recent years, received ever-widening interest as a multicarrier digital transmission scheme because of its simplicity in implementation, high spectral efficiency, and robustness against such channel impairments as multipath, impulse noise, and fast fading. One key drawback of using OFDM, however, is the magnitude of its peak power relative to the average power of the signal, known as the peak-to-average power ratio (PAPR). We present the basic theory of OFDM transmission and develop a new technique, the Block Segmentation Procedure*, illustrating its simplicity in implementation and reasonable PAPR versus data rate tradeoff. Block Segmentation may provide benefits for OFDM in the presence or absence of any scheme that makes use of redundant information (coding included), with no limitation on the number of carriers. In order to demonstrate the procedure, the method of peak reduction coefficients is augmented, yielding an appreciably increased PAPR reduction for 4–16 carrier OFDM. The effects of Block Segmentation on system error performance are investigated in noisy channels. Alternative methods of “PAPR prediction” are presented in order to simplify the hardware expenditure required for Block Segmentation in practical usage. Block Segmentation is compared to an alternative PAPR reduction technique—complementary coding—in order to illustrate the possible superiority of using separate methods of error correction and PAPR reduction, respectively, over the amalgamation of the two requirements in one solution. Finally, Block Segmentation's degradation when transmitted through a multipath channel is investigated in order to ensure that Block Segmentation will not be a limiting factor on system error performance.; *Patent pending... |
