Title :
Practical implementation of PN scrambler for PAPR reduction in OFDM systems for range extension and lower power consumption
Author :
Moffatt, Christopher ; Kostanic, Ivica
Author_Institution :
Harris Corp., Melbourne, FL
Abstract :
Orthogonal Frequency Division Modulation (OFDM) is an efficient multi-carrier modulation scheme. It is used in many wireless communication systems due to its robustness towards fading channel behavior and a relative ease of implementation coming from computationally efficient Inverse Fast Fourier Transforms (IFFT). However, the OFDM waveform has a very large Peak-to-Average Power Ratio (PAPR). Therefore, to avoid clipping plus nonlinear distortion, the Power Amplifier (PA) needs to be backed off significantly. This paper proposes a novel implementation and analysis of a Pseudorandom Noise (PN) scrambling technique allowing a significant reduction of the OFDM signalpsilas PAPR. The theoretical basis for the technique is presented, and a particular implementation of the technique for the IEEE 802.11a standard is discussed. Both simulations and measurements demonstrate significant benefits of the proposed technique in longer range wireless communications applications that use OFDM.
Keywords :
OFDM modulation; fading channels; fast Fourier transforms; power amplifiers; IEEE 802.11a standard; OFDM systems; fading channel; inverse fast Fourier transforms; multicarrier modulation scheme; orthogonal frequency division modulation; peak-to- average power ratio; power amplifier; pseudorandom noise scrambling technique; range extension; wireless communication systems; Energy consumption; Fading; Fast Fourier transforms; Frequency conversion; Frequency modulation; Nonlinear distortion; OFDM modulation; Peak to average power ratio; Robustness; Wireless communication;
Conference_Titel :
Military Communications Conference, 2008. MILCOM 2008. IEEE
Conference_Location :
San Diego, CA
Print_ISBN :
978-1-4244-2676-8
Electronic_ISBN :
978-1-4244-2677-5
DOI :
10.1109/MILCOM.2008.4753540