Method and apparatus for detecting CPM-modulated information symbols
AssigneeSiemens Mobile Communications S.p.A.
InventorsBernhard Spinnler, Berthold Lankl, Johannes Huber
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Abstract
Demodulation of CPM-modulated information symbols which are demodulated after being transmitted through an AWGN channel, using only partial whitened matched filtering, whereby finite pulses are produced which, however, are still accompanied by interferences in the form of remaining colored noise which can be approximately converted into white noise by a successive additional whitening filter so that the noise power will be minimized. For correcting the accompanying symbol interferences, a sequence estimation with reduced number of states follows.
Claims14
A method for detecting CPM-modulated information symbols, comprising the steps of:
- transmitting CPM signals through an AWGN channel;
- incoherently demodulating the CPM signal by a frequency discriminator into a signal bD(t) or by differential demodulation into a signal bDD(t);
- passing the demodulated signal through a partially whitened matched filter;
- sampling the demodulated signal with a symbol clock after having passed through the whitened matched filter,
- wherein,
- the signal is subject to only partial whitened matched filtering, whereby signal pulses decrease at the expense of a rest of colored noise remaining.
An apparatus for detecting CPM-modulated information symbols, comprising:
- a signal source containing an AWGN channel transmitting CPM signals modulated with information signals and containing a demodulator for said CPM signals, and
- downstream of said signal source, a whitened matched filter for said demodulated signals and a signal sampler following said whitened matched filter and operating with the signal clock, said filter being a partial whitened matched filter dimensioned such that it supplies at its output finite response pulses accompanied by remaining colored noise.
Dependencies are inferred from the claim text.