A numerical method for spectral shaping of CPM signals

Author

Freidhof, Markus ; Havezov, Peter

Author_Institution

Inst. for Commun. Technol., Darmstadt Univ. of Technol., Germany

Volume

5

fYear

1998

fDate

1998

Firstpage

2859

Abstract

A new method for spectral shaping of the power density spectrum (PDS) of continuous phase modulation (CPM) is presented. The PDS is multiplied with a weighting function, integrated and minimized to control the shaping of the PDS. For an easy calculation of the PDS the CPM signal is disassembled into amplitude modulated pulses. A gradient search method is used for the optimization of the nonlinear set of equations. It is shown with some examples, that the optimization can shape the PDS in a purposeful manner. In the given examples the out-of-band power or the adjacent channel interference (ACI) is reduced. In order to control the trade-off between the power efficiency and the ACI, the object function of the optimization is expanded with a term which takes into account the free Euclidian distance. The results are compared to Gaussian minimum shift keying (GMSK) for various BT

Keywords

adjacent channel interference; amplitude modulation; continuous phase modulation; nonlinear equations; optimisation; signal processing; spectral analysis; ACI; CPM signals; GMSK; Gaussian minimum shift keying; adjacent channel interference; amplitude modulated pulses; continuous phase modulation; free Euclidian distance; gradient search method; mobile communications systems; nonlinear equations optimization; nonlinear modulation; numerical method; out-of-band power; power density spectrum; power efficiency; spectral shaping; weighting function; Amplitude modulation; Assembly; Equations; Fourier transforms; Frequency; Phase modulation; Pulse modulation; Search methods;

fLanguage

English

Publisher

ieee

Conference_Titel

Global Telecommunications Conference, 1998. GLOBECOM 1998. The Bridge to Global Integration. IEEE

Conference_Location

Sydney,NSW

Print_ISBN

0-7803-4984-9

Type

conf

DOI

10.1109/GLOCOM.1998.776593

Filename

776593