Orthogonal frequency chirp multiple accessing systems and methods
OwnerRajendra Kumarinventor
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Abstract
Various embodiments of the invention are directed to orthogonal frequency chirp multiple accessing (OFCM) systems and methods. For example, various embodiments of the OFCM transmitter may utilize an architecture comprised of a baseband modulation subsystem, a subsystem for generating multiplicity N orthogonal frequency chirp waveforms, and a bank of multiplicity N spread spectrum modulators. Various embodiments of the OFCM receiver may comprise of a subsystem for generating complex conjugates of multiplicity N orthogonal frequency chirp waveforms, a bank of multiplicity N spread spectrum demodulators, a symbol estimator, a symbol timing estimator, a frequency offset estimator, a carrier phase tracking loop, a multi channel estimator, and a baseband demodulation subsystem.
Claims21
An OFCM (Orthogonal Frequency Chirp Multiple accessing) transmitter system comprised of:
- a baseband modulation subsystem for receiving and modulating a plurality of input data signals providing a multiplicity Nu, in general complex valued, information baseband symbols;
- a subsystem for generating multiplicity NT frequency chirp waveforms;
- a bank of multiplicity NT spread spectrum modulators modulating the frequency chirp waveforms by the information baseband symbols for providing multiplicity NT spread spectrum signals;
- and
- an adder summing the spread spectrum signals for providing a serial OCFM signal comprised of a plurality of consecutive OCFM symbols.
An OCFM receiver comprised of:
- a receive antenna for receiving a radio frequency (RF) band pass OCFM signal;
- an RF front stage unit comprised of an RF filter, amplifier and down converter for providing an Intermediate Frequency (IF) band pass OCFM signal;
- a carrier phase tracking loop;
- a cascade of an IF to complex baseband converter, an analog to digital converter, and a guard interval deletion unit for providing an estimated serial OFCM signal;
- a frequency chirp waveform generator for providing a multiplicity NR complex conjugates frequency chirp waveforms;
- a bank of multiplicity NR spread spectrum demodulators;
- a symbol estimator for providing linear estimates of the information baseband symbols;
- a bank of multiplicity Nu decision devices for detection of the information baseband symbols;
- and
- a baseband demodulation subsystem for providing estimated input data signals.
A method for the OFCM transmission and reception of a plurality of input data signals, the transmission method comprising:
- implementing, by a computer device, a baseband modulation subsystem for receiving and modulating the input data providing a multiplicity Nu, in general complex valued, information baseband symbols;
- implementing, by the computer device, a subsystem for generating multiplicity NR frequency chirp waveforms;
- implementing, by the computer device, a bank of multiplicity NR spread spectrum modulators modulating the frequency chirp waveforms by the information baseband symbols for providing multiplicity Nm spread spectrum signals;
- implementing, by the computer device, an adder summing the spread spectrum signals for providing a serial OCFM signal comprised of the consecutive OCFM symbols;
- and
- implementing, by the computer device, a guard interval insertion unit for cyclically extending the consecutive OCFM symbols by guard intervals providing a baseband OCFM signal.
Dependencies are inferred from the claim text.