Ultrawide-band communication system and method

• US 6,031,862 A
• Filed: 10/10/1997
• Issued: 02/29/2000
• Est. Priority Date: 09/20/1994
• Status: Expired due to Fees

• Current Assignee: Time Domain Corporation (Humatics Corporation)
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Fullerton, Larry W., Cowie, Ivan A.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Maddox, Michael W.
• Application Number:
  US08/948,781
• Time in Patent Office: 872 Days
• Field of Search: 370/210, 370/280, 370/324, 370/342, 370/503, 370/213, 375/200, 375/239, 375/241-242, 375/296, 375/256, 375/259, 375/353, 375/295, 375/206, 375/208, 375/210
• US Class Current: 375/146
• 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. 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;

b. a code source that uses a periodic timing signal to output a code signal;

c. a summer to receive said modulated subcarrier signal and said code signal and output a code modulated subcarrier signal;

d. a code and time modulator to modulate said periodic timing signal using said code modulated subcarrier signal and output a modulated, coded timing signal; and

e. an output stage to generate an impulse radio signal using said modulated, coded timing signal, wherein said impulse radio signal comprises monocycle pulses spaced in time.

2. The impulse radio transmitter according to claim 1, wherein said code source comprises means for pseudo noise coding a data signal to produce said code signal.

3. The impulse radio transmitter according to claim 2, wherein said data signal is encoded by a return-to-zero direct digital encoder.

4. The impulse radio transmitter according to claim 3, wherein said return-to-zero 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.

5. The impulse radio transmitter according to claim 1, wherein said output stage uses an antenna to transmit said impulse radio signal into a propagation medium.

6. The impulse radio transmitter according to claim 5, further comprising a transmission line coupled between said output stage and said antenna.

7. A method for transmitting impulse radio signals, comprising the steps of:

(1) modulating a subcarrier signal using an information signal to output a modulated subcarrier signal;

(2) producing a code signal using a periodic timing signal;

(3) summing said modulated subcarrier signal and said code signal to output a code modulated subcarrier signal;

(4) modulating said periodic timing signal using said code modulated subcarrier signal to output a modulated, coded timing signal; and

(5) generating an impulse radio signal using said modulated, coded timing signal, wherein said impulse radio signal comprises monocycle pulses spaced in time.