Performance analysis of coded multicarrier spread-spectrum systems in the presence of multipath fading and nonlinearities

Author

Jong, Je-Hong ; Stark, Wayne E.

Author_Institution

Lockheed Martin Global Telecommun., Clarksburg, MD, USA

Volume

49

Issue

1

fYear

2001

fDate

1/1/2001 12:00:00 AM

Firstpage

168

Lastpage

179

Abstract

In this paper, we analyze the effects of a nonlinear amplifier on the performance of convolutionally coded multicarrier spread-spectrum systems in the presence of multipath fading. Two performance measures, bit-error rate (BER) and adjacent channel power ratio (ACPR) are considered to assess the effects of in-band interference and out-of-band interference (spectral regrowth) from the nonlinear amplifier, respectively. A memoryless polynomial model is used to represent the bandpass amplifier amplitude nonlinearities (AM/AM) and a slow frequency-nonselective Rayleigh fading channel is assumed for each modulated carrier. Analytical results for the BER for uncoded systems and upper bounds on the BER for coded systems are presented. The optimum amplifier output power backoffs for both systems, which yield the smallest system power consumption, are also determined. The obtained ACPR shows its slow (inverse linear) falloff with the amplifier output backoff

Keywords

AWGN; OFDM modulation; Rayleigh channels; amplitude modulation; convolutional codes; error statistics; modulation coding; multipath channels; power amplifiers; radiofrequency amplifiers; radiofrequency interference; spread spectrum communication; AM/AM; AWGN; BER; adjacent channel power ratio; bandpass amplifier amplitude nonlinearities; bit-error rate; coded multicarrier spread-spectrum systems; coded systems; convolutionally coded systems; in-band interference; memoryless polynomial model; modulated carrier; multipath fading; nonlinear amplifier; nonlinearities; optimum amplifier output power backoff; out-of-band interference; performance analysis; performance measures; slow frequency-nonselective Rayleigh fading channel; spectral regrowth; system power consumption; uncoded systems; upper bounds; Bit error rate; Convolutional codes; Fading; Interference; Performance analysis; Polynomials; Power amplifiers; Power measurement; Power system modeling; Spread spectrum communication;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.898260

Filename

898260