Adaptive Step Size for OFDM CFR with Cognitive Clipping

Author

Ma, Wanzhi ; Shao, Shihai ; Tang, Youxi

Author_Institution

Nat. Key Lab. of Sci. & Technol. on Commun., Univ. of Electron. Sci. & Technol. of China, Chengdu, China

fYear

2010

fDate

23-25 Sept. 2010

Firstpage

1

Lastpage

4

Abstract

In this paper, an adaptive step size algorithm is proposed to reduce peak-to-average power ratio (PAR) of OFDM signals. The error vector magnitude (EVM) and spectral mask constraints are considered. Unlike the existing cognitive clipping method, the proposed scheme adjusts the EVM threshold with adaptive step size, which is proportionate to the ratio between PAR of each OFDM symbol and that required by system. Compared with the original method, the new algorithm offers more than 0.2 dB PAR reduction at 10^-4 complementary cumulative distribution function (CCDF) level and 20% iteration reduction for 256 subcarriers QPSK WiMAX signal.

Keywords

OFDM modulation; WiMax; cognitive radio; quadrature phase shift keying; EVM threshold; OFDM CFR; OFDM symbol; PAR reduction; QPSK WiMAX signal; adaptive step size algorithm; cognitive clipping; complementary cumulative distribution function; peak to average power ratio; Bit error rate; Chromium; Degradation; Frequency domain analysis; Peak to average power ratio; WiMAX;

fLanguage

English

Publisher

ieee

Conference_Titel

Wireless Communications Networking and Mobile Computing (WiCOM), 2010 6th International Conference on

Conference_Location

Chengdu

Print_ISBN

978-1-4244-3708-5

Electronic_ISBN

978-1-4244-3709-2

Type

conf

DOI

10.1109/WICOM.2010.5600196

Filename

5600196