A new approach to improve BER performance of a high Peak-to-Average ratio (PAR) OFDM signal over FM based Land Mobile Radios (LMR)

Author

Navalekar, Abhijit C. ; Michalson, William R.

Author_Institution

Dept. of Electr. & Comput. Eng., Worcester Polytech. Inst, Worcester, MA

fYear

2008

fDate

24-26 April 2008

Firstpage

158

Lastpage

164

Abstract

The performance for a FM system depends upon the RMS bandwidth (f_r) of the modulated FM signal and the bandwidth (W) of the modulating signal. Increasing the RMS value of the modulating signal (sigma_x) increases the RMS bandwidth of the FM signal. A typical FM radio clips the input modulating signal above a predefined threshold (A_c) to limit the maximum deviation (f_d) of the carrier frequency so as to avoid interference on adjacent channels. Thus a high peak-to-average (PAR) OFDM modulating signal will undergo non-linear distortion due to clipping by the FM radio. In this paper the effects of distortion due to clipping on the OFDM/FM system the will be studied. The performance limitations will be investigated for M-ary QAM modulation (M=16, 64, 256) and different IDFT sizes (N=64,256,512). A simple scaling method is proposed to improve the signal-to-noise ratio (SNR) at the FM receiver which would improve BER performance of the OFDM signal.

Keywords

OFDM modulation; discrete Fourier transforms; error statistics; frequency modulation; land mobile radio; nonlinear distortion; quadrature amplitude modulation; BER performance; FM radio; FM receiver; FM signal; FM system; IDFT; M-ary QAM modulation; OFDM signal; distortion effects; land mobile radios; nonlinear distortion; peak-to-average ratio; signal-to-noise ratio; Bandwidth; Bit error rate; Frequency modulation; Land mobile radio; Nonlinear distortion; OFDM modulation; Peak to average power ratio; Quadrature amplitude modulation; RF signals; Radiofrequency interference;

fLanguage

English

Publisher

ieee

Conference_Titel

Wireless Telecommunications Symposium, 2008. WTS 2008

Conference_Location

Pomona, CA

ISSN

1934-5070

Print_ISBN

978-1-4244-1869-5

Electronic_ISBN

1934-5070

Type

conf

DOI

10.1109/WTS.2008.4547560

Filename

4547560