Ultrafast time hopping CDMA and TDMA RF and optical communications: code-as-carrier, multichannel operation, high data rate operation and data rate on demand

• US 6,160,802 A
• Filed: 03/07/1997
• Issued: 12/12/2000
• Est. Priority Date: 07/29/1994
• Status: Expired due to Fees

• Current Assignee: Barrett Holding LLC
• Original Assignee: Barrett Holding LLC
• Inventors: Barrett, Terence W.
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): Nguyen, Kim T.
• Application Number:
  US08/813,176
• Time in Patent Office: 1,376 Days
• Field of Search: 370/335, 370/342, 370/347, 370/203, 370/206, 370/208, 370/213, 370/441, 370/503, 370/520, 375/200, 375/206, 375/203, 375/239
• US Class Current: 370/342
• CPC Class Codes: H04B 1/7176 Data mapping, e.g. modulation
• CPC Class Codes: H04B 2001/6908 using time hopping
• CPC Class Codes: H04B 7/2634 for channel frequency control
• CPC Class Codes: H04J 13/0074 Code shifting or hopping

Abstract

Ultrashort pulse time hopping code-division-multiple-access (CDMA) and time-division-multiple-access (TDMA) RF IR and optical communications systems in the time-frequency domain comprises a transmitter including a short duration pulse/packet generator for generating a short duration pulse/packet in the femtosecond to microsecond range and a controller for controlling the generator, code means connected to the controller for varying the time position of each short pulse/packet in frames of pulses/packets in orthogonal superframes of ultrafast time hopping code and time division multiple access format, precise oscillator-clock for controlling such timing, encoding modems for transforming intelligence into pulse/packet position modulation form, antenna/amplifier system. Preferably, the codes are orthogonal codes with the temporal coding of the sequence of ultrafast pulses/packets constituting the carrier for transmission by the antenna system.

Claims

1. An ultrashort pulse time hopping code-division-multiple-access (CDMA) or time-division-multiple-access (TDMA) optical communications system in the time frequency domain, comprising:

transmitter means, said transmitter means including;

a) means for generating a short duration pulse or packet in the femitosecond to microsecond range and means for controlling said means for generating,

b) coding means connected to said means for controlling for varying the time position of each said short duration pulse or packet in frames of pulses or packets in orthogonal superframes of ultrafast time hopping code and time division multiple access format,

c) precise oscillator-clock means for controlling such timing,

d) encoding modems for transforming information, voice and data signals into pulse position modulation form,

e) antenna means connected to said means for generating for receiving and broadcasting said short duration pulse or packet as a coded broadcast signal,

receiver means, said receiver means including;

a) antenna means for receiving said coded broadcast signal, and

b) homodyne or heterodyne receiver means for receiving and decoding said coded broadcast signal.

2. The optical communication system defined in claim 1 wherein said coding means includes means for generating sequences of ultrafast, ultrashort pulses or packets, means for interval modulating said sequences according to an orthogonal code which positions each pulse or packet within a set macrowindow.

3. The optical communication system defined in claim 2 wherein said macrowindow set by the assigned code includes microwindows and said means for pulse position modulating, modulates the position of an individual pulse or packet within a microwindow of each macrowindow set by the assigned code such that information is encoded in each said microwindow.

4. The optical communication system defined in claim 1 wherein said coding means includes codes stored in matrix form memories including EPROM memories and with superframes of received signals representing the assigned code, orthogonal to other assigned codes, matched against said stored codes.

5. The optical communication system defined in claim 4 wherein said codes are orthogonal codes with the temporal coding of the sequence of ultrafast, ultrashort pulses or packets constituting the carrier for transmission by said transmit antenna means.

6. The optical communication system defined in claim 4 wherein said homodyne receiver means includes a bank of decoder/modems, an acquisition system/matched filter for synchronizing said orthogonal superframe for transmission, identifying coded sequences in the superframe by said acquisition/matched filter and assigning said superframe transmissions to a selected decoder/modem.

7. The communication system defined in claim 1 which is adapted for multichannel operation and which provides a high overall data rate in the 500 mbs and greater range for maximum multichannel or aggregate operation.

8. The optical communication system defined in claim 1, comprising means for increasing the number N of orthogonal codes available wherein the number of orthogonal codes available comprising a first family of codes, the number (y) of orthogonal codes available to a second family of codes, and the number (n) of orthogonal codes available to an n'"'"'th family, means entraining said families, and using matched filter acquisition such that the total number of codes available is x X y X n, wherein x is the number of codes in the first family;

y is the number of codes in the second family, and n is the number of codes in the n'"'"'th family.

9. The optical communication system defined in claim 1, comprising means for increasing the number of orthogonal codes available wherein the clock rate for a first set of "a" orthogonal codes is A cycles/sec, the clock rate for a second set of "b" orthogonal codes is B, and the clock rate for an n'"'"'th set of "n" orthogonal codes is N, then by clock syncopation, and means including separate matched filters at clock rates A, B, . . . N, the total number of codes available is a+b+ . . . +n, where "a" is the number of codes in the first set;

"b" is the number of codes in the second set;

. . . and "n" is the number of codes in the `n'"'"'th` set;

A is the first clock rate;

. . . N is the "n"th clock rate, if the matched filter outputs are not entrained, and a X b X . . . X n if the matched filter outputs are entrained.

10. A transmitter for ultrashort pulse time hopping code-division-multiple-access (CDMA) and time-divisional-multiple-access (TDMA) optical communications system in the time frequency domain, comprising:

a) a short duration pulse or packet generator means for generating a short duration pulse or packet in the picosecond through nano-second to microsecond range and means for controlling said short duration pulse or packet generator,

b) a coding unit connected to said means for controlling for varying the time position of each said short duration pulse or packet in frames of pulses or packets in orthogonal superframes of ultrafast time hopping code and time division multiple access format,

c) a precise oscillator-clock for controlling such timing,

d) encoding modems for transforming information, voice and data signals into pulse position modulation form, and

e) an antenna connected to said short duration pulse or packet generator for receiving and broadcasting said short duration pulse or packet as a coded broadcast signal.

11. A transmitter for an ultrashort pulse time hopping code-division-multiple-access (CDMA) or time-division-multiple-access (TDMA) communications system in the time frequency domain, said transmitter comprising:

a generator for generating a short duration pulse or packet in the femitosecond to microsecond range and means for controlling said generator,

coding system connected to said means for varying the time position of each said short duration pulse or packet in frames of pulses or packets in orthogonal superframes of ultrafast time hopping code and time division multiple access format,

encoding modem means for transforming information, voice and data signals into pulse position modulation form and form a short pulse or packet coded broadcast signal, and

an antenna connected to said short duration pulse or packet generator for receiving and broadcasting said broadcast signal.