Polyopoly overlapping spread spectrum communication system and method

• US 5,274,665 A
• Filed: 08/05/1991
• Issued: 12/28/1993
• Est. Priority Date: 12/14/1990
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Schilling, Donald L.
• Primary Examiner(s): Swann, Tod R.
• Application Number:
  US07/739,806
• Time in Patent Office: 876 Days
• Field of Search: 375/1, 375/38, 375/48, 375/66, 375/89, 455/59, 455/103, 455/209, 455/216, 455/303, 380/33, 380/34, 380/40
• US Class Current: 375/144
• CPC Class Codes: G01S 13/82 wherein continuous-type signals are transmitted
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/18547 for geolocalisation of a station position fixing by direction or distance determination G01S5/00
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/346 distributing total power among users or channels

Abstract

Two, three or more competitive personal communications network spread spectrum systems share spectrum without interfering with each other, without significantly decreasing the chip rate of each PCN system, and without increasing the level of interference seen by fixed service users. A duopoly of spread spectrum communications system includes a first transmitter station, a second transmitter station, a first receiver station and a second receiver station. A transmitter at the second transmitter station transmits a spread spectrum signal on a carrier frequency which is offset from the carrier frequency of the first transmitter at the transmitter station by the chip rate. A tripoly of spread spectrum communication system includes the elements of the duopoly spread spectrum system and further includes a third transmitter station and a third receiver station. A third transmitter at the third transmitter station transmits a spread spectrum signal on a carrier frequency which is offset from the first carrier frequency by twice the chip rate. The first, second and third receiver stations each have receivers which receive the respect of spread spectrum signals from the first, second and third transmitter stations. A polyopoly overlapping spread spectrum communications system may be used which allows many users to transmit and receive throughout the frequency regime.

Claims

1. A spread spectrum communications system for use over a communications channel, comprising:

a first transmitter-generic-chip-code generator for generating a first generic-chip-code signal having a chip rate;

a first transmitter-message-chip-code generator for generating a first message-chip-code signal having the chip rate;

a first EXCLUSIVE-OR gate coupled to said first transmitter-message-chip-code generator for spread-spectrum processing first message data with the first message-chip-code signal to generate a first spread-spectrum signal;

a first combiner coupled to said first transmitter-generic-chip-code generator and said first EXCLUSIVE-OR gate for combining the first generic-chip-code signal with the first spread-spectrum-processed signal;

a first transmitter coupled to said first combiner for transmitting the combined first generic-chip-code signal and first spread-spectrum-processed signal, on a first carrier signal at a first carrier frequency over said communications channel as a first spread-spectrum-communications signal;

a second transmitter-generic-chip-code generator for generating a second generic-chip-code signal having the chip rate;

a second transmitter-message-chip-code generator for generating a second message-chip-code signal having the chip rate;

a second EXCLUSIVE-OR gate coupled to said second transmitter-message-chip-code generator for spread-spectrum processing second message data with the second message-chip-code signal to generate a second spread-spectrum signal;

a second combiner coupled to said second transmitter-generic-chip-code generator and said second EXCLUSIVE-OR gate for combining the second generic-chip-code signal with the second spread-spectrum-processed signal;

a second transmitter coupled to said second combiner for transmitting the combined second generic-chip-code signal and second spread-spectrum-processed signal, on a second carrier signal at a second carrier frequency offset from the first carrier frequency by the chip rate, over said communications channel as a second spread-spectrum-communications signal;

a first receiver-generic-chip-code generator for generating a replica of the first generic-chip-code signal;

a first generic mixer coupled to said first receiver-generic-chip-code generator for recovering the first carrier signal from the first spread-spectrum-communications signal as a first recovered-carrier signal;

a first receiver-message-chip-code generator coupled to said first receiver-generic-chip-code signal for generating a replica of the first message-chip-code signal;

a first message mixer coupled to said first receiver-message-chip-code generator responsive to the replica of the first message-chip-code signal for despreading the first spread-spectrum-communications signal as a first modulated-data signal;

a first message-bandpass filter coupled to said first receiver-message-mixer device for filtering the first modulated-data signal;

a first-generic-bandpass filter coupled to said first generic-mixer device for filtering the first recovered-carrier signal recovered from the first spread-spectrum-communications signal;

a first tracking and acquisition circuit coupled to an output of said first generic-bandpass filter and to said first receiver-generic-chip-code generator, said first tracking and acquisition circuit responsive to acquiring and tracking the first recovered-carrier signal for synchronizing the first generic-chip-code signal to the first recovered-carrier signal;

a first power splitter coupled between said communications channel, said first generic-mixer device and said first receiver-message-mixer device for dividing the first spread-spectrum-communications signal between said first generic-mixer device and said first receiver-message-mixer device;

a first synchronous detector coupled to said first message-bandpass filter and said first generic-bandpass filter, responsive to the first recovered-carrier signal recovered by the first generic-mixer device for synchronously demodulating the first modulated-data signal as a first detected signal;

a second receiver-generic-chip-code generator for generating a replica of the second generic-chip-code signal;

a second generic mixer coupled to said second receiver-generic-chip-code generator for recovering the second carrier signal from the second spread-spectrum-communications signal as a second recovered-carrier signal;

a second receiver-message-chip-code generator coupled to said second receiver-generic-chip-code signal and synchronized to the replica of the second generic-chip-code signal for generating a replica of the second message-chip-code signal;

a second message mixer coupled to said second receiver-message-chip-code generator responsive to the replica of the second message-chip-code signal for despreading the second spread-spectrum-communications signal as a second modulated-data signal;

a second message-bandpass filter coupled to said second receiver-message-mixer device for filtering the second modulated-data signal;

a second-generic-bandpass filter coupled to said second generic-mixer device for filtering the second recovered-carrier signal recovered from the second spread-spectrum-communications signal;

a second tracking and acquisition circuit coupled to an output of said second generic-bandpass filter and to said second receiver-generic-chip-code generator, said second tracking and acquisition circuit responsive to acquiring and tracking the second recovered-carrier signal for synchronizing the second generic-chip-code signal to the second recovered-carrier signal;

a second power splitter coupled between said communications channel, said second generic-mixer device and said second receiver-message-mixer device for dividing the second spread-spectrum-communications signal between said second generic-mixer device and said second receiver-message-mixer device; and

a second synchronous detector coupled to said second message-bandpass filter and said second generic-bandpass filter, responsive to the second recovered-carrier signal recovered by the second generic-mixer device for synchronously demodulating the second modulated-data signal as a second detected signal.

2. A spread spectrum communications system for use over a communications channel comprising:

first message means for generating a first message-chip-code signal having a chip rate;

first spreading means for spread-spectrum processing first message data with the first message-chip-code signal to generate a first spread-spectrum-processed signal;

first means for transmitting the first spread-spectrum-processed signal on a first carrier signal at a first carrier frequency over said communications channel as a first spread-spectrum-communications signal;

second message means for generating a second message-chip-code signal having the chip rate;

second spreading means for spread-spectrum processing second message data with the second message-chip-code signal to generate a second spread-spectrum-processed signal;

second means for transmitting the second spread-spectrum-processed signal on a second carrier signal at a second carrier frequency offset from the first carrier frequency by the chip rate over said communications channel as a second spread-spectrum-communications signal;

first message-spread-spectrum-processing means for despreading the first spread-spectrum-communications signal as a first modulated-data signal;

first detection means for detecting the first modulated-data signal as a first detected signal;

first bit-synchronization means for synchronously converting the first detected signal as first received data;

second message-spread-spectrum-processing means for despreading the second spread-spectrum-communications signal as a second modulated-data signal;

second detection means for detecting the second modulated-data signal as a second detected signal; and

second bit-synchronization means responsive to the second generic-chip-code signal for synchronously converting the second detected signal as second received data.

3. The spread spectrum communications system as set forth in claim 2 further including:

at least third message means for generating a third message-chip-code signal having the chip rate;

at least third spreading means for spread-spectrum processing third message data with the third message-chip-code signal to generate a third spread-spectrum-processing signal;

at least third means for transmitting the third spread-spectrum-processed signal on a third carrier signal at a third carrier frequency offset from the first carrier frequency by twice the chip rate over said communications channel as a third spread-spectrum-communications signal;

at least third message-spread-spectrum-processing means for despreading the third spread-spectrum-communications signal as a third modulated-data signal;

at least third detection means for detecting the third modulated-data signal as a third detected signal; and

at least third bit-synchronization means responsive to the third generic-chip-code signal for synchronously converting the third detected signal as third received data.

4. The spread spectrum communications system as set forth in claim 2 further including:

first generic means for generating a first generic-chip-code signal;

first summer means for combining the first generic-chip-code signal with the first spread-spectrum-processed signal;

said first transmitting means transmits the combined first generic-chip-code signal and first spread-spectrum-processed signal;

first generic-spread-spectrum-processing means for recovering the first carrier signal from the first spread-spectrum-communications signal as a first recovered-carrier signal and for generating a replica of the first generic-chip-code signal;

first acquisition means responsive to acquiring and tracking the first recovered-carrier signal for synchronizing said first generic-spread-spectrum-processing means to the first recovered-carrier signal; and

wherein said first bit-synchronization means is responsive to the first generic-chip-code signal for synchronously converting the first detected signal as first received data.

5. The spread spectrum communications system as set forth in claim 4 wherein each of said first and second detection means includes an envelope detector for converting the first and second modulated-data signals to the first and second detected signals, respectively.

6. The spread spectrum communications system as set forth in claim 4 further including:

second generic means for generating a second generic-chip-code signal;

second summer means for combining the second generic-chip-code signal with the second spread-spectrum-processed signal;

said second transmitting means transmits the combined second generic-chip-code signal and second spread-spectrum-processed signal;

second generic-spread-spectrum-processing means for recovering the second carrier signal from the second spread-spectrum-communications signal as a second recovered-carrier signal and for generating a replica of the second generic-chip-code signal;

second acquisition means responsive to acquiring and tracking the second recovered-carrier signal for synchronizing said second generic-spread-spectrum-processing means to the second recovered-carrier signal; and

wherein said second bit-synchronization means is responsive to the second generic-chip-code signal for synchronously converting the second detected signal as second received data.

7. The spread spectrum communications system as set forth in claim 6 wherein each of said first and second detection means includes a synchronous detector responsive to the first and second recovered-carrier signal, respectively, for converting the first and second modulated-data signals to the first and second detected signals, respectively.

8. The spread spectrum communications system as set forth in claim 6 wherein each of said first and second bit-synchronization means further includes:

a lowpass filter;

an electronic switch coupled at an output of said lowpass filter; and

a bit-synchronizer coupled to said first and second generic-spread-spectrum-processing means, respectively, and responsive to the replica of the first and second generic-chip-code signals, respectively, for integrating and dumping said lowpass filter and said electronic switch, respectively.

9. The spread spectrum communications system as set forth in claim 2 wherein each of said first and second bit-synchronization means further includes:

a lowpass filter;

an electronic switch coupled at an output of said lowpass filter; and

a bit-synchronizer responsive to the first and second received data at an input to said lowpass filter for integrating and dumping said lowpass filter and said electronic switch, respectively.

10. A method for synchronously demodulating spread spectrum communications, comprising the steps of:

generating a first message-chip-code signal having a chip rate;

spread-spectrum processing first message data with the first message-chip-code signal to generate a first spread-spectrum-processed signal;

transmitting the first spread-spectrum-processed signal on a first carrier signal at a first carrier frequency over said communications channel as a first spread-spectrum-communications signal;

generating a second message-chip-code signal having the chip rate;

spread-spectrum processing second message data with the second message-chip-code signal to generate a second spread-spectrum-processed signal;

transmitting the second spread-spectrum-processed signal on a second carrier signal at a second carrier frequency offset from the first carrier frequency by the chip rate over said communications channel as a second spread-spectrum-communications signal;

generating a replica of the first message-chip-code signal synchronized to the replica of the first generic-chip-code signal;

despreading, using the replica of the first message-chip-code signal, the first spread-spectrum-communication signal as a first modulated-data signal;

demodulating the first modulated-data signal as first received data;

generating a replica of the second message-chip-code signal synchronized to the replica of the second generic-chip-code signal;

despreading, using the replica of the second message-chip-code signal, the second spread-spectrum-communications signal as a second modulated-data signal; and

demodulating the second modulated-data signal as second received data.

11. The method as set forth in claim 10 further including the steps of:

generating at least third message-chip-code signal having the chip rate;

spread-spectrum processing at least third message data with the at least third message-chip-code signal to generate at least third spread-spectrum-processed signal;

transmitting the at least third spread-spectrum-processed signal on at least third carrier signal at a respective at least third carrier frequency offset from the first carrier frequency by the chip rate over said communications channel as at least third spread-spectrum-communications signal;

generating a replica of the at least third message-chip-code signal synchronized to the replica of the at least third generic-chip-code signal;

despreading, using the replica of the at least third message-chip-code signal, the at least third spread-spectrum-communications signal as at least third modulated-data signal; and

demodulating the at least third modulated-data signal as at least third received data.

12. The method as set forth in claim 11 further including the steps of:

recovering, using a replica of a first generic-chip-code signal, the first carrier signal from the first spread-spectrum-communications signal as a first recovered-carrier signal;

acquiring and tracking the first recovered-carrier signal;

generating the replica of the first generic-chip-code signal synchronized to the first recovered-carrier signal; and

synchronizing the replica of the first generic-chip-code signal to the first recovered-carrier signal.

13. The method as set forth in claim 10 further including the steps of:

recovering, using a replica of a first generic-chip-code signal, the first carrier signal from the first spread-spectrum-communications signal as a first recovered-carrier signal;

acquiring and tracking the first recovered-carrier signal;

generating the replica of the first generic-chip-code signal synchronized to the first recovered-carrier signal;

recovering, using a replica of the second generic-chip-code signal, the second carrier signal from the second spread-spectrum-communications signal as a second recovered-carrier signal;

acquiring and tracking the second recovered-carrier signal;

generating the replica of the second generic-chip-code signal synchronized to the second recovered-carrier signal;

synchronizing the replica of the first generic-chip-code signal to the first recovered-carrier signal; and

synchronizing the replica of the second generic-chip-code signal to the second recovered-carrier signal.

14. The method as set forth in claim 13 wherein each demodulating step includes synchronously demodulating, using the first and second recovered-carrier signals, respectively, the first and second modulated-data signals, respectively, as first and second detected signals, respectively.

15. The method as set forth in claim 13 further including the steps of:

generating at least third message-chip-code signal having the chip rate;

spread-spectrum processing at least third message data with the at least third message-chip-code signal to generate at least third spread-spectrum-processed signal;

transmitting the at least third spread-spectrum-processed signal on at least third carrier signal at a respective at least third carrier frequency offset from the first carrier frequency by the chip rate over said communications channel as at least third spread-spectrum-communications signal;

generating a replica of the at least third message-chip-code signal synchronized to the replica of the at least third generic-chip-code signal;

despreading, using the replica of the at least third message-chip-code signal, the at least third spread-spectrum-communications signal as at least third modulated-data signal; and

demodulating the at least third modulated-data signal as at least third received data.

16. The method as set forth in claim 15 further including the steps of:

recovering, using a replica of at least third generic-chip-code signal, the at least third carrier signal from the at least third spread-spectrum-communications signal as at least third recovered-carrier signal, respectively;

acquiring and tracking the at least third recovered-carrier signal;

generating the replica of the first generic-chip-code signal synchronized to the first recovered-carrier signal; and

synchronizing the replica of the at least third generic-chip-code signal to the at least third recovered-carrier signal.

17. The method as set forth in claim 16 wherein each demodulating step includes synchronously demodulating, using the first, second, and at least third recovered-carrier signals, respectively, the first, second, and at least third modulated-data signals, respectively, as first, second, and at least third detected signals, respectively.

18. A spread spectrum communication system for use over a communications channel, comprising:

first generic means for generating a first generic-chip-code signal;

a first plurality of message means for generating a first plurality of message-chip-code signals;

a first plurality of spreading means for spread-spectrum processing the first plurality of message data with the first plurality of message-chip-code signals to generate a first plurality of spread-spectrum-processed signals;

first summer means for combining the first generic-chip-code signal with the first plurality of spread-spectrum-processed signals;

first means for transmitting the combined first generic-chip-code signal and the first plurality of spread-spectrum-processed signals, on a first carrier signal at a first carrier frequency over said communications channel as a first spread-spectrum-communications signal;

second generic means for generating a second generic-chip-code signal;

a second plurality of message means for generating a second plurality of message-chip-code signals;

a second plurality of spreading means for spread-spectrum processing the second plurality of message data with the second plurality of message-chip-code signals to generate a second plurality of spread-spectrum-processed signals;

second summer means for combining the second generic-chip-code signal with the second plurality of spread-spectrum-processed signals;

second means for transmitting the combined second generic-chip-code signal and the second plurality of spread-spectrum-processed signals, on a second carrier signal at a second carrier frequency over said communications channel as a second spread-spectrum-communications signal;

first generic-spread-spectrum-processing means for recovering the first carrier signal from the first spread-spectrum-communications signal as a first recovered-carrier signal, and for generating a replica of the first generic-chip-code signal;

first acquisition means responsive to acquiring and tracking the first recovered-carrier signal for synchronizing said first generic-spread-spectrum-processing means to the first recovered-carrier signal;

a first plurality of message-spread-spectrum-processing means synchronized to the replica of the first generic-chip-code signal for despreading the first spread-spectrum-communications signal as a first plurality of modulated-data signals;

a first plurality of detection means for detecting the first plurality of modulated-data signals as a first plurality of detected signals;

second generic-spread-spectrum-processing means for recovering the second carrier signal from the second spread-spectrum-communications signal as a second recovered-carrier signal, and for generating a replica of the second generic-chip-code signal;

second acquisition means responsive to acquiring and tracking the second recovered-carrier signal for synchronizing said second generic-spread-spectrum-processing means to the second recovered-carrier signal;

a second plurality of message-spread-spectrum-processing means synchronized to the replica of the second generic-chip-code signal for despreading the second spread-spectrum-communications signal as a second plurality of modulated-data signals; and

a second plurality of detection means of detecting the second plurality of modulated-data signals as a second plurality of detected signals.

19. The spread spectrum communications system as set forth in claim 18 further comprising:

first bit-synchronization means responsive to the first generic-chip-code signal for synchronously converting the first plurality of detected signals as first received data;

second bit-synchronization means responsive to the second generic-chip-code signal for synchronously converting the second plurality of detected signals as second received data.

20. The spread spectrum communications system as set forth in claim 19 wherein each of said first and second bit-synchronization means further includes:

a lowpass filter;

an electronic switch coupled at an output of said lowpass filter; and

a bit-synchronizer responsive to the first and second received data at an input to said lowpass filter for integrating and dumping said lowpass filter and said electronic switch, respectively.

21. The spread spectrum communications system as set forth in claim 19 wherein each of said first and second bit-synchronization means further includes:

a lowpass filter;

an electronic switch coupled at an output of said lowpass filter; and

a bit-synchronizer coupled to said first and second generic-spread-spectrum-processing means, respectively, and responsive to the replica of the first and second generic-chip-code signals, respectively, for integrating and dumping said lowpass filter and said electronic switch, respectively.

22. The spread spectrum communications system as set forth in claim 18 further comprising:

at least third generic means for generating at least third generic-chip-code signal;

at least third plurality of message means for generating at least third plurality of message-chip-code signals;

at least third plurality of spreading means for spread-spectrum processing said at least third plurality of message data with the at least third plurality of message-chip-code signals to generate at least third plurality of spread-spectrum-processed signals;

at least third summer means for combining the at least third generic-chip-code signal and the at least third plurality of spread-spectrum-processed signals;

at least third means for transmitting the combined at least third generic-chip-code signal and the at least third plurality of spread-spectrum-processed signals, on at least third carrier signal at a respective at least third carrier frequency over said communications channel as at least third spread-spectrum-communications signal;

at least third generic-spread-spectrum-processing means for recovering the at least third carrier signal from the at least third spread-spectrum-communications signal as at least third recovered-carrier signal, and for generating, respectively, a replica of the at least third generic-chip-code signal;

at least third acquisition means responsive to acquiring and tracking the at least third recovered-carrier signal for synchronizing said at least third generic-spread-spectrum-processing means to the at least third recovered-carrier signal;

at least third plurality of message-spread-spectrum-processing means synchronized, respectively, to the replica of the at least third generic-chip-code signal for despreading the at least third spread-spectrum-communications signal as at least third plurality of modulated-data signals; and

at least third plurality of detection means for detecting the at least third plurality of modulated-data signals as at least third plurality of detected signals.

23. The spread spectrum communications system as set forth in claim 22 wherein each of said first, second, and at least third plurality of detection means includes a synchronous detector responsive to the first, second and at least third recovered-carrier signal, respectively, for converting the first, second, and at least third plurality of modulated-data signals, respectively, to the first, second, and at least third plurality of detected signals, respectively.

24. The spread spectrum communications system as set forth in claim 22 wherein each of said first, second, and at least third plurality of detection means includes an envelope detector for converting the first, second, and at least third plurality of modulated-data signals, respectively, to the first, second, and at least third plurality of detected signals, respectively.

25. The spread spectrum communications system as set forth in claim 22 further comprising:

at least third bit-synchronization means responsive to the at least third generic-chip-code signal for synchronously converting the at least third plurality of detected signals as at least third received data.

26. The spread spectrum communications system as set forth in claim 25 wherein each of said first, second, and at least third bit-synchronization means further includes:

a lowpass filter;

an electronic switch coupled at an output of said lowpass filter; and

a bit-synchronizer responsive to the first, second, and at least third received data at an input to said lowpass filter for integrating and dumping said lowpass filter and said electronic switch, respectively.

27. The spread spectrum communications system as set forth in claim 25 wherein each of said first, second and at least third bit-synchronization means further includes:

a lowpass filter;

an electronic switch coupled at an output of said lowpass filter; and

a bit-synchronizer coupled to said first, second, and at least third generic-spread-spectrum-processing means, respectively, and responsive to the replica of the first, second, and at least third generic-chip-code signals, respectively, for integrating and dumping said lowpass filter and said electronic switch, respectively.

28. The spread spectrum communications system as set forth in claim 18 wherein each of said first plurality of detection means and each of said second plurality of detection means includes an envelope detector for converting the first plurality of modulated-data signals and the second plurality of modulated-data signals to the first plurality of detected signals and the second plurality of detected signals, respectively.

29. The spread spectrum communications system as set forth in claim 18 wherein each of said first plurality of detection means and each of said second plurality of detection means includes a synchronous detector responsive to the first and second recovered-carrier signal, respectively, for converting the first and second plurality of modulated-data signals, respectively, to the first and second plurality of detected signals, respectively.