Optimal finite duration pulses for OFDM

Author

Vahlin, A. ; Holte, Nils

Author_Institution

Dept. of Telecommun., Norwegian Inst. of Technol., Trondheim, Norway

Volume

44

Issue

1

fYear

1996

fDate

1/1/1996 12:00:00 AM

Firstpage

10

Lastpage

14

Abstract

This paper presents pulses of finite duration for use in orthogonal frequency division multiplexing (OFDM) using offset QAM modulation. In such a system the pulses will overlap in both frequency and time without intersymbol or interchannel interference. The pulses are generated by an optimization procedure which minimizes the out-of-band energy under the constraints of zero intersymbol and interchannel interference. Low out-of-band energy is important to achieve high bandwidth efficiency, especially when the number of channels is small. The optimization procedure leads to an integral equation which is solved by expanding the pulse in truncated prolate spheroidal wave functions. Examples of optimized pulses and their spectrum are presented for lengths of 2 and 4 symbol intervals

Keywords

frequency division multiplexing; integral equations; intersymbol interference; optimisation; quadrature amplitude modulation; spectral analysis; wave functions; OFDM; high bandwidth efficiency; integral equation; multicarrier modulation; offset QAM modulation; optimal finite duration pulses; optimization procedure; optimized pulses; orthogonal frequency division multiplexing; out-of-band energy minimisation; pulse generation; pulse lengths; pulse shaping; pulse spectrum; symbol intervals; truncated prolate spheroidal wave functions; zero interchannel interference; zero intersymbol interference; Bandwidth; Constraint optimization; Integral equations; Interchannel interference; Interference constraints; OFDM modulation; Pulse generation; Pulse modulation; Quadrature amplitude modulation; Wave functions;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.476088

Filename

476088