Flat-spectrum and spectrum-shaped waveforms for digital communications
OwnerVlad Mitlininventor
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Abstract
In accordance with the present invention, there is provided a method of generating, for a given natural q, a set of q complex sequences of a constant envelope DFT-transformed into sequences also of a constant envelope. It is shown that these sequences are transformed into themselves upon applying the DFT twice. A digital communications method with enhanced bandwidth and transmitted power utilization employing these sequences as basic transmission objects is described. Finally, a method of generating complex sequences identical to their discrete spectra is described.
Claims11
A method of reducing the peak-to-average power ratio of a complex waveform obtained as the q-point inverse discrete Fourier transform of a complex message of the length q comprising:
- generating a complex, constant envelope sequence of the length q such that its q-point discrete Fourier transform is of a constant envelope;
- and
- multiplying the r-th component of the message by the r-th component of the sequence, for integer r such that 0≦r<q.
A method of data transmission comprising:
- generating n≧2 different complex, constant envelope sequences of the length q such that their q-point discrete Fourier transforms are of a constant envelope;
- said sequences are mapped to an alphabet consisting of n different symbols;
- there is a data stream of said symbols at a transmitting station;
- a current symbol from said data stream is mapped to one of the sequences;
- said sequence is converted to an analog signal;
- said signal is transmitted over the communication channel and received, digitized, and identified at the receiving station.
An authentication method for communications between a transmitting station and a receiving station comprising:
- at the transmitting station an authentication waveform is generated and transmitted;
- the authentication waveform is identical to its discrete Fourier spectrum;
- at the receiving station the waveform is received and identified;
- the identification is performed by computing the mean of the waveform and its discrete Fourier transform at least once and comparing the result to all valid authentication waveforms stored at the receiving station;
- in the case of a positive identification communications continue;
- in the case of a negative identification communications end;
Dependencies are inferred from the claim text.