Iterative clipping and filtering (ICF) is a widely used technique to reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals. However, the ICF technique, when implemented with a fixed rectangular window in the frequency-domain, requires many iterations to approach specified PAPR threshold in the complementary cumulative distribution function (CCDF). In this paper, we develop an optimized ICF method which determines an optimal frequency response filter for each ICF iteration using convex optimization techniques. The design of optimal filter is to minimize signal distortion such that the OFDM symbol's PAPR is below a specified value. Simulation results show that our proposed method can achieve a sharp drop of CCDF curve and reduce PAPR to an acceptable level after only 1 or 2 iterations, whereas the classical ICF method would require 8 to 16 iterations to achieve a similar PAPR reduction. Moreover, the clipped OFDM symbols obtained by our optimized ICF method have less distortion and lower out-of-band radiation than the existing method.
Bibliographical noteFunding Information:
The work of the first author is supported by National Important Science Technology Specific Project (2010ZX03006-002-04, 2009ZX03003-001), National 863 project of China (2009AA01Z237), the Fundamental Research Funds for the Central Universities (K50510010009), and 111 Project (B08038). The research of the second author is supported in part by the National Science Foundation, Grant No. DMS-060037.
- Orthogonal frequency division multiplexing
- convex optimization
- iterative clipping and filtering
- peak-to-average power ratio