CDMA communications and geolocation system and method

• US 5,365,544 A
• Filed: 02/23/1994
• Issued: 11/15/1994
• Est. Priority Date: 12/05/1990
• 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): CANGIALOSI, SALVATORE A
• Application Number:
  US08/178,016
• Time in Patent Office: 265 Days
• Field of Search: 375/1, 380/34, 342/457, 342/450
• US Class Current: 370/342
• 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 1/71 the interference being narrowband interference
• CPC Class Codes: H04B 1/7102 with transform to frequency domain
• CPC Class Codes: H04B 7/18547 for geolocalisation of a station position fixing by direction or distance determination G01S5/00
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04B 7/2631 for broadband transmission
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• 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
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A spread-specttrm CDMA communications system for locating remote units, and for communicating message data between a plurality of remote units and a base station. The spread-spectrum CDMA communications system includes a plurality of base stations and a plurality of remote units. A base station has a spread-spectrummodulator for spread-spectrum processing the message data, and a transmitter for transmitting the spread-spectrum processed-message data, combined with a generic-chip-code signal, from the base station to a remote unit. The base station also has an antenna, and spread-spectrum detectors for recovering message-data communicated from the remote-units. A remote-unit has an antenna, and a detector coupled to the antenna for recovering data communicated from the base station. The detector includes a spread spectrum demodulator. Also, the remote unit has a device for converting the format of the data into a form suitable for communicating over radio waves, a spread spectrum modulator and a transmitter. The base station has a range circuit, which compares the generic-chip-code signal generated at the base station with the generic-chip-code signal received from the remote unit, for determining a range between the remote unit and the base station.

Claims

1. A spread-spectrum CDMA communications system for communicating base-message data to a plurality of remote units, and range locating each of said remote units, said spread-spectrum CDMA communications system comprising:

a plurality of base stations for communicating base-message data to the plurality of remote units, each of said base stations including,

base-spreading means for spread-spectrum processing the base-message data;

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

base-combiner means for combining the base-generic-chip-code signal with the spread-spectrum-processed-base-message data, thereby generating a base-CDMA signal;

base-transmitter means for transmitting the base-CDMA signal from said base station to said remote unit;

a base antenna coupled to said base-transmitter means;

each of said remote units including,

a remote antenna;

remote-detection means, coupled to said remote antenna, for detecting the base-generic-chip-code signal embedded in the base-CDMA signal, and for recovering, using the detected-base-generic-chip-code signal, the base-message data communicated from said base station;

remote-spreading means for spread-spectrum processing remote-message data;

remote-combiner means, responsive to the detected-generic-chip-code signal and the spread-spectrum-processed-remote data for generating a remote-CDMA signal;

remote-transmitter means for transmitting the remote-CDMA signal from the remote unit to said base station;

wherein each of said base stations further includes,

base-detection means, coupled to said base antenna, for detecting the remote-generic-chip-code signal embedded in the remote-CDMA signal, and for recovering, using the detected-remote-generic-chip-code signal, the remote-message data communicated from said remote unit; and

range means, responsive to the detected- remote-generic-chip-code signal and the base-generic-chip-code signal for determining a range delay between said remote unit and said base station.

2. The spread-spectrum CDMA communications system as set forth in claim 1 wherein said base-transmitter means transmits the base-CDMA signal on a base-carrier frequency and said remote-transmitter means transmits the remote-CDMA signal on a remote carrier frequency, with the remote-carrier frequency different from the base-carrier frequency, for separating a bandwidth of the base-CDMA signal from a bandwidth of the remote-CDMA signal.

3. The spread-spectrum CDMA communications system as set forth in claim 1 wherein said base-transmitter means transmits the base CDMA signal with a burst format on a first carrier frequency, and said remote-transmitter means, responsive to receiving the base-CDMA signal, transmits the remote-CDMA signal with a burst format on the first carrier frequency.

4. The spread-spectrum CDMA communications system as set forth in claim 1 wherein said remote-detection means includes means for synchronizing the spread-spectrum-processed-message data embedded in the base-CDMA signal with the detected-base-generic-chip-code signal.

5. The spread-spectrum CDMA communications system as set forth in claim 1 wherein said base-processing means at said base station includes means for processing message data for particular remote units with a selected chip code.

6. The spread-spectrum CDMA communications system as set forth in claim 1 wherein said remote-detection means includes:

a message-chip-code generator for generating a message-chip-code signal with a chip-codeword corresponding to the remote unit;

a product detector for mixing the message-chip-code signal with a received base-CDMA signal;

a bandpass filter for filtering the detected spread-spectrum signal; and

a data detector for detecting base-message data in the detected spread-spectrum signal.

7. The spread-spectrum CDMA communications system as set forth in claim 1 wherein said remote-detection means includes:

a matched filter having an impulse response matched to a message-chip-code signal used at said base station; and

a data detector for detecting message data at an output of said matched filter.

8. A spread-spectrum CDMA communications system for communicating base-message data to a plurality of remote units, and range locating each of said remote units, said spread-spectrum CDMA communications system comprising:

at least one base station for communicating base-message data to the plurality of remote units, each of said base stations including,

a base-spread-spectrum modulator for spread-spectrum processing the message data;

a base-generic-chip-code generator for generating a base-generic-chip-code signal;

a base combiner for combining the base-generic-chip-code signal with the spread-spectrum-processed-base-message data, thereby generating a base-CDMA signal;

a base transmitter for transmitting the base-CDMA signal from said base station to said remote unit;

a base antenna coupled to said base transmitter;

a plurality of remote units each of said remote units including,

a remote antenna;

a remote-unit detector, coupled to said remote antenna, for detecting the base-generic-chip-code signal embedded in the base-CDMA signal, and for recovering, using the detected-base-generic-chip-code signal, the base-message data communicated from said base station;

a remote-spread-spectrummodulator for spread-spectrum processing remote-unit-message data;

a remote-unit combiner, responsive to the detected-generic-chip-code signal and the spread-spectrum-processed-remote data for generating a remote-CDMA signal;

a remote unit transmitter for transmitting the remote-CDMA signal from the remote unit to the base station;

wherein each of said base stations further includes.

a base detector, coupled to said base antenna, for detecting the remote-generic-chip-code signal embedded in the remote-CDMA signal, and for recovering, using the detected-remote-generic-chip-code signal, the remote message data communicated from said remote unit; and

a range circuit, responsive to the detected-remote-generic-chip-code signal and the base-generic-chip-code signal for determining a range delay between said remote unit and said base station.

9. The spread-spectrum CDMA communications system as set forth in claim 8 wherein said base transmitter transmits the base-CDMA signal on a base-carrier frequency and said remote-transmitter means transmits the remote-CDMA signal on a remote carrier frequency, with the remote-carrier frequency different from the base-carrier frequency, for separating a bandwidth of the base-CDMA signal from a bandwidth of the remote-CDMA signal.

10. The spread-spectrum CDMA communications system as set forth in claim 8 wherein said base transmitter transmits the base-CDMA signal with a burst format on a first carrier frequency, and said remote-unit transmitter, responsive to said remote unit receiving the base-CDMA signal, transmits the remote-CDMA signal with a burst format on the first carrier frequency.

11. The spread-spectrum CDMA communications system as set forth in claim 8 wherein said remote-unit detector includes means for synchronizing the spread-spectrum-processed-message data embedded in the base-CDMA signal with the detected-base-generic-chip-code signal.

12. The spread-spectrum CDMA communications system as set forth in claim 8 wherein said base-spread-spectrum-modulator at said base station includes means for processing message data for particular remote units with a selected chip code.

13. The spread-spectrum CDMA communications system as set forth in claim 8 wherein said remote-unit detector includes:

a message-chip-code generator for generating a message-chip-code signal with a chip-codeword corresponding to the remote unit;

a product detector for mixing the message-chip-code signal with a received base-CDMA signal;

a bandpass filter for filtering the detected spread-spectrum signal; and

a data detector for detecting message data in the detected spread-spectrum signal.

14. The spread-spectrum CDMA communications system as set forth in claim 8 wherein said remote-unit detector includes:

a matched filter having an impulse response matched to a message-chip-code signal used at said base station; and

a data detector for detecting base-message data at an output of said matched filter.

15. A spread-spectrum CDMA communications system for communicating remote-message data to a base station, and range locating at each of said remote units, said spread-spectrum CDMA communications system comprising:

a plurality of remote units for communicating remote-message data to at least one base station, each of said remote units including,

remote-spreading means for spread-spectrum processing the remote-message data;

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

remote-combiner means for combining the remote-generic-chip-code signal with the spread-spectrum-processed-remote-message data, thereby generating a remote-CDMA signal;

remote-transmitter means for transmitting the remote-CDMA signal from said remote unit to said base station;

a remote antenna coupled to said remote-transmitter means;

said base station including,

a base antenna;

base-detection means, coupled to said base antenna, for detecting the remote-generic-chip-code signal embedded in the remote-CDMA signal, and for recovering, using the detected-remote-generic-chip-code signal, the remote-message data communicated from said remote unit;

base processing means for spread-spectrum processing base-message data;

base-combiner means, responsive to the detected-remote-generic-chip-code signal and the spread-spectrum-processed-base-message data for generating a base-CDMA signal;

base-transmitter means for transmitting the base-CDMA signal from the base station to the remote unit;

wherein at least one of said remote units further includes,

remote-detection means, coupled to said remote antenna, for detecting the base-generic-chip-code signal embedded in the base-CDMA signal, and for recovering, using the detected-base-generic-chip-code signal, the base-message data communicated from said base station; and

range means, responsive to the detected-base-generic-chip-code signal and the remote-generic-chip-code signal, for determining a range delay between said remote unit and said base station.

16. The spread-spectrum CDMA communications system as set forth in claim 15 wherein said base-transmitter means transmits the base-CDMA signal on a base-carrier frequency and said remote-transmitter means transmits the remote-CDMA signal on a remote carrier frequency, with the remote-carrier frequency different from the base-carrier frequency, for separating a bandwidth of the base-CDMA signal from a bandwidth of the remote-CDMA signal.

17. The spread-spectrum CDMA communications system as set forth in claim 15 wherein said remote-transmitter means transmits the remote-CDMA signal with a burst format on a first carrier frequency, and said base-transmitter means, responsive to receiving the remote-CDMA signal, transmits the base-CDMA signal with a burst format on the first carrier frequency.

18. The spread-spectrum CDMA communications system as set forth in claim 15 wherein said remote-detection means includes means for synchronizing the spread-spectrum-processed-message data embedded in the base-CDMA signal with the detected-base-generic-chip-code signal.

19. The spread-spectrum CDMA communications system as set forth in claim 15 wherein said base-processing means at said base station includes means for processing message data for particular remote units with a selected chip code.

20. The spread-spectrum CDMA communications system as set forth in claim 15 wherein said remote-detection means includes:

a message-chip-code generator for generating a message-chip-code signal with a chip-codeword corresponding to the remote unit;

a

product detector for mixing the message-chip-code signal with a received base-CDMA signal;

a bandpass filter for filtering the detected spread-spectrum signal; and

a data detector for detecting message data in the detected spread-spectrum signal.

21. The spread-spectrum CDMA communications system as set forth in claim 15 wherein said remote-detection means includes:

a matched filter having an impulse response matched to a message-chip-code signal used at said base station; and

a data detector for detecting base-message data at an output of said matched filter.

22. A spread-spectrum CDMA communications system for communicating remote-message data to a base station, and range locating at each of said remote units, said spread-spectrum CDMA communications system comprising:

a plurality of remote units for communicating remote-message data to a base station, each of said remote units including,

a remote-spread-spectrummodulator for spread-spectrum processing the remote-message data;

a remote-generic-chip-code generator for generating a remote-generic-chip-code signal;

a remote-unit combiner for combining the remote-generic-chip-code signal with the spread-spectrum-processed-remote-message data, thereby generating a remote-CDMA signal;

a remote-unit transmitter for transmitting the remote-CDMA signal from said remote unit to said base station;

a remote antenna coupled to said remote-unit transmitter;

said base station including,

a base antenna;

base-detection means, coupled to said base antenna, for detecting the remote-generic-chip-code signal embedded in the remote-CDMA signal, and for recovering, using the detected-remote-generic-chip-code signal, the remote-message data communicated from said remote unit;

a base spread-spectrummodulator for spread-spectrum processing base-message data;

a base combiner, responsive to the detected-generic-remote-chip-code signal and the spread-spectrum-processed-base-message data for generating a base-CDMA signal;

a base transmitter for transmitting the base-CDMA signal from the base station to the remote unit;

wherein at least one of said remote units further includes,

a remote detector, coupled to said remote antenna, for detecting the base-generic-chip-code signal embedded in the base-CDMA signal, and for recovering, using the detected-base-generic-chip-code signal, the base message data communicated from said base station; and

a range circuit, responsive to the detected-base-generic-chip-code signal and the remote-generic-chip-code signal for determining a range delay between said remote unit and said base station.

23. The spread-spectrum CDMA communications system as set forth in claim 22 wherein said base transmitter transmits the base-CDMA signal on a base-carrier frequency and said remote-unit transmitter transmits the remote-CDMA signal on a remote carrier frequency, with the remote-carrier frequency different from the base-carrier frequency.

24. The spread-spectrum CDMA communications system as set forth in claim 22 wherein said remote transmitter transmits the remote-CDMA signal with a burst format on a first carrier frequency, and said base transmitter, responsive to receiving at the base station the remote-CDMA signal, transmits the base-CDMA signal with a burst format on the first carrier frequency.

25. The spread-spectrum CDMA communications system as set forth in claim 22 wherein said remote detector includes means for synchronizing the spread-spectrum-processed-base-message data embedded in the base-CDMA signal with the detected-base-generic-chip-code signal.

26. The spread-spectrum CDMA communications system as set forth in claim 22 wherein said base spread-spectrum modulator includes means for processing message data for particular remote units with a selected chip code.

27. The spread-spectrum CDMA communications system as set forth in claim 22 wherein said remote detector includes:

a message-chip-code generator for generating a message-chip-code signal with a chip-codeword corresponding to the remote unit;

a product detector for mixing the message-chip-code signal with a received base-CDMA signal;

a bandpass filter for filtering the detected spread-spectrum signal; and

a data detector for detecting message data in the detected spread-spectrum signal.

28. The spread-spectrum CDMA communications system as set forth in claim 22 wherein said remote detector includes:

a matched filter having an impulse response matched to a message-chip-code signal used at said base station; and

a data detector for detecting base-message data at an output of said matched filter.

29. A spread-spectrum CDMA communications method for communicating base-message data to a plurality of remote units, and range locating each of said remote units, said spread-spectrum CDMA communications method comprising the steps of:

spread-spectrum processing the base-message data;

generating a base-generic-chip-code signal;

combining the base-generic-chip-code signal with the spread-spectrum-processed-base-message data, thereby generating a base-CDMA signal;

transmitting the base-CDMA signal from said base station to said remote unit;

detecting the base-generic-chip-code signal embedded in the base-CDMA signal;

recovering, using the detected-base-generic-chip-code signal, the base-message data;

spread-spectrum processing remote-message data;

generating, using the detected-generic-chip-code signal and the spread-spectrum-processed-remote data, a remote-CDMA signal;

transmitting the remote-CDMA signal from the remote unit to the base station;

detecting the remote-generic-chip-code signal embedded in the remote-CDMA signal;

recovering, using the detected-remote-generic-chip-code signal, the remote-message data; and

determining, using the detected-remote-generic-chip-code signal and the base-generic-chip-code signal, a range delay between said remote unit and said base station.

30. The spread-spectrum CDMA communications method as set forth in claim 29 wherein:

the step of transmitting the base-CDMA signal includes the steps of transmitting the base-CDMA signal on a base-carrier frequency; and

the step of transmitting the remote-CDMA signal includes the step of transmitting the remote-CDMA signal on a remote carrier frequency, with the remote-carrier frequency different from the base-carrier frequency.

31. The spread-spectrum CDMA communications method as set forth in claim 29 wherein:

the step of transmitting the base-CDMA signal includes the step of transmitting with a burst format; and

the step of transmitting the remote-CDMA signal is in response to receiving the base-CDMA signal.

32. The spread-spectrum CDMA communications method as set forth in claim 29 wherein the step of spread-spectrum processing the base-message data includes the step of spread-spectrum processing the base-message data with a selected chip code.

33. The spread-spectrum CDMA communications system as set forth in claim 29 wherein said base-processing means at said base station includes means for processing message data for particular remote units with a selected chip code.

34. The spread-spectrum CDMA communications method as set forth in claim 29 wherein the step of detecting includes:

generating a message-chip-code signal with a chip-codeword corresponding to the remote unit;

mixing the message-chip-code signal with a received base-combined-spread-spectrum signal;

filtering the detected spread-spectrum signal; and

detecting base-message data in the detected spread-spectrum signal.

35. The spread-spectrum CDMA communications method as set forth in claim 29 wherein the step of detecting includes:

matched filtering with an impulse response matched to a message-chip-code signal used at said base station; and

detecting base-message data after the step of matched filtering.

36. A spread-spectrum CDMA communications method for communicating base-message data from a plurality of base stations to a plurality of remote units, and range locating each of said plurality of remote units, and for communicating remote-message data from said plurality of remote units to said plurality of base stations, said spread-spectrum CDMA communication method comprising the steps of:

spread-spectrum processing the base-message data;

generating a base-generic-chip-code signal;

generating a base-generic-chip-code signal with the spread-spectrum-processed-base-message data, thereby generating a base-CDMA signal;

transmitting the base-CDMA signal from a base station to a remote unit;

receiving the base-CDMA signal at the remote unit;

detecting the base-generic-chip-code signal embedded in the base-CDMA signal;

recovering, using the detected-base-generic-chip-code signal, the base-message data;

spread-spectrum processing the remote-message data;

generating a remote-generic-chip-code signal;

generating, using the remote-generic-chip-code signal and the spread-spectrum-processed-remote-message data, a remote-CDMA signal;

transmitting the remote-CDMA signal from the remote unit to the base station;

receiving the remote-CDMA signal at the base station;

detecting the remote-generic-chip-code signal embedded in the remote-CDMA signal;

recovering, using the detected-remote-generic-chip-code signal, the remote-message data; and

determining, using the detected-remote-generic-chip-code signal and the base-generic-chip-code signal, a range delay between the remote unit and the base station.

37. The spread-spectrum CDMA communications method as set forth in claim 36 wherein:

the step of transmitting the base-CDMA signal includes the steps of transmitting the base-CDMA signal on a base-carrier frequency; and

the step of transmitting the remote-CDMA signal includes the step of transmitting the remote-CDMA signal on a remote carrier frequency, with the remote-carrier frequency different from the base-carrier frequency.

38. The spread-spectrum CDMA communications method as set forth in claim 36 wherein:

the step of transmitting the base-CDMA signal includes the step of transmitting with a burst format; and

the step of transmitting the remote-CDMA signal is in response to receiving the base-CDMA signal.

39. The spread-spectrum CDMA communications method as set forth in claim 36 wherein the step of spread-spectrum processing the base-message data includes the step of spread-spectrum processing the base-message data with a selected chip code.

40. The spread-spectrum CDMA communications system as set forth in claim 36 wherein said base-processing means at said base station includes means for processing message data for particular remote units with a selected chip code.

41. The spread-spectrum CDMA communications method as set forth in claim 36 wherein the step of detecting includes:

generating a message-chip-code signal with a chip-codeword corresponding to the remote unit;

mixing the message-chip-code signal with a received base-combined-spread-spectrum signal;

filtering the detected spread-spectrum signal; and

detecting base-message data in the detected spread-spectrum signal.

42. The spread-spectrum CDMA communications method as set forth in claim 36 wherein the step of detecting includes:

matched filtering with an impulse response matched to a message-chip-code signal used at said base station; and

detecting base-message data after the step of matched filtering.