Convergence of the complex envelope of bandlimited OFDM signals
IEEE Transactions on Information Theory
| Hi-index | 754.90 |
This paper addresses the problem of determining the statistical distribution of the peak-to-average power ratio (PAR) of orthogonal frequency-division multiplexing (OFDM) transmit signals. In practice, transmission systems are amplitude-limited, thus the large peak values of OFDM signals are clipped and nonlinear distortion follows. In order to avoid the resulting degradations, i.e., spectral widening and increased bit-error rate, a systematic construction of OFDM signals without large peaks is desired. The paper provides new results on the PAR distribution and hence on the achievable information rate with OFDM signals that are peak-limited. In particular, it is shown that in the case of phase-shift-keying (PSK) subcarrier modulation, the frequently applied model of Gaussian data coefficients is not appropriate. By solving an integral equation, new analytic expressions for the PAR and the achievable information rate are derived. Comparison with simulation results confirms that the new model is accurate for all ranges of practical interest