Ultrawide-band communication system and method

• US 20030043931A1
• Filed: 07/17/2002
• Published: 03/06/2003
• Est. Priority Date: 09/20/1994
• Status: Active Grant

• Current Assignee: TDC Acquisition Holdings, Inc (Humatics Corporation)
• Original Assignee: Pulson Communications Corporation
• Inventors: Fullerton, Larry W., Cowie, Ivan A.
• Granted Patent: US 6,847,675 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/70753 Partial phase search
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 1/71632 Signal aspects H04B1/7172 and H04B1/7176 take precedence
• CPC Class Codes: H04B 1/71635 Transmitter aspects H04B1/7174 takes precedence
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence
• CPC Class Codes: H04B 1/7176 Data mapping, e.g. modulation
• CPC Class Codes: H04B 1/7183 Synchronisation
• CPC Class Codes: H04B 14/026 using pulse time characteristics modulation, e.g. width, position, interval
• CPC Class Codes: H04B 2001/6908 using time hopping
• CPC Class Codes: H04B 2201/70707 Efficiency-related aspects
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An impulse radio communications system using one or more subcarriers to communicate information from an impulse radio transmitter to an impulse radio receiver. The impulse radio communication system is an ultrawide-band time domain system. The use of subcarriers provides impulse radio transmissions added channelization, smoothing and fidelity. Subcarriers of different frequencies or waveforms can be used to add channelization of impulse radio signals. Thus, an impulse radio link can communicate many independent channels simultaneously by employing different subcarriers for each channel. The impulse radio uses modulated subcarrier(s) for time positioning a periodic timing signal or a coded timing signal. Alternatively, the coded timing signal can be summed or mixed with the modulated subcarrier(s) and the resultant signal is used to time modulate the periodic timing signal. Direct digital modulation of data is another form of subcarrier modulation for impulse radio signals. Direct digital modulation can be used alone to time modulate the periodic timing signal or the direct digitally modulated the periodic timing signal can be further modulated with one or more modulated subcarrier signals. Linearization of a time modulator permits the impulse radio transmitter and receiver to generate time delays having the necessary accuracy for impulse radio communications.

Claims

1. An impulse radio transmitter, comprising:

a time base to output a periodic timing signal;

a subcarrier modulator to receive a subcarrier signal and an information signal and modulate said subcarrier signal using said information signal and output a modulated subcarrier signal; and

an output stage to generate an impulse radio signal based on said periodic timing signal and said modulated subcarrier signal, wherein said impulse radio signal comprises pulses spaced in time.

2. The impulse radio transmitter of claim 1, further comprising:

a code source that uses said periodic timing signal to output a code signal, wherein said output stage generates said impulse radio signal based on said code signal and said modulated subcarrier signal.

3. An impulse radio transmitter, comprising:

a time base to output a periodic timing signal;

an encoder to receive a digital data signal and output a encoded digital data signal; and

an output stage to generate an impulse radio signal based on said periodic timing signal and said encoded digital data signal, wherein said impulse radio signal comprises pulses spaced in time.

4. The impulse radio transmitter of claim 3, wherein said encoder comprises a return-to-zero encoder.

5. The impulse radio transmitter of claim 3, wherein said encoder comprises one of a pseudo Manchester encoder, a frequency shift keying encoder, an n-ary phase modulation encoder and a phase amplitude modulation encoder.

6. The impulse radio transmitter of claim 3, further comprising:

a code source that uses said periodic timing signal to output a code signal, wherein said output stage generates said impulse radio signal based on said code signal and said encoded digital data signal.

17. The method of claim 5, wherein said encoding comprises one of pseudo Manchester encoding, frequency shift keying encoding, n-ary phase modulation encoding and phase amplitude modulation encoding.

18. The method of claim 5, further comprising:

producing a code signal based on the periodic timing signal; and

generating the impulse radio signal based on the code signal and the encoded digital data signal.

7. A system for direct digitally encoding a data signal for impulse radio communications, comprising:

an impulse radio transmitter having an encoder that direct digitally encodes the data signal to produce a direct digitally encoded data signal; and

an impulse radio receiver having a decoder and a phase-locked loop, wherein said direct digitally encoding avoids errors in the phase-locked loop.

8. The system of claim 7, wherein said encoder comprises a return-to-zero encoder.

9. The system of claim 7, wherein said encoder comprises one of a pseudo Manchester encoder, a frequency shift keying encoder, an n-ary phase modulation encoder and a phase amplitude modulation encoder.

10. An impulse radio receiver, comprising:

a cross correlator to cross correlate a received impulse radio signal with a decode signal to output a baseband signal;

a lowpass filter that uses the baseband signal to output an error signal;

an adjustable time base, responsive to the error signal, to control lock of the cross correlation; and

a subcarrier demodulator, responsive to the baseband signal, to output a demodulated information signal.

11. The impulse radio receiver according to claim 10, wherein the subcarrier demodulator is a direct digital demodulator.

12. The impulse radio receiver according to claim 11, wherein the direct digital demodulator comprises a pseudo Manchester decoder.

13. A method for generating an impulse radio signal, comprising:

producing a periodic timing signal;

modulating a subcarrier signal using an information signal to output a modulated subcarrier signal; and

generating the impulse radio signal based on the periodic timing signal and the modulated subcarrier signal, wherein the impulse radio signal comprises pulses spaced in time.

14. The method of claim 13, further comprising:

producing a code signal based on the periodic timing signal; and

generating the impulse radio signal based on the code signal and the modulated subcarrier signal.

15. A method for generating an impulse radio signal, comprising:

producing a periodic timing signal;

encoding a digital data signal to output an encoded digital data signal; and

generating an impulse radio signal based on the periodic timing signal and the encoded digital data signal, wherein the impulse radio signal comprises pulses spaced in time.

16. The method of claim 15, wherein said encoding comprises return-to-zero encoding.

19. A method for receiving impulse radio signals, comprising:

cross correlating a received impulse radio signal with a decode signal to output a baseband signal;

demodulating the baseband signal to output a subcarrier signal; and

demodulating the subcarrier signal to output an information signal.

20. The method according to claim 19, wherein said demodulating the baseband signal step comprises direct digitally demodulating the baseband signal to output the subcarrier signal.

21. The method according to claim 20, wherein said step of direct digitally demodulating further comprises pseudo Manchester decoding.

22. The method according to claim 19, further comprising:

lowpass filtering the baseband signal to output an error signal; and

adjusting a periodic timing signal using the error signal to time position the decode signal in relation to the position of the received impulse radio signal thereby optimizing the cross correlation.