CDMA/TDMA spread-spectrum communications system and method

• US RE35,402 E
• Filed: 07/05/1994
• Issued: 12/17/1996
• Est. Priority Date: 01/13/1992
• 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): Cain, David C.
• Application Number:
  US08/277,142
• Time in Patent Office: 896 Days
• Field of Search: 375/1, 375/203, 380/34, 380/49
• US Class Current: 375/143
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04L 7/043 Pseudo-noise [PN] codes variable during transmission synchronisation of spread spectrum receivers H04B1/69
• CPC Class Codes: H04L 7/046 using a dotting sequence

Abstract

A spread-spectrum transmitter and receiver using code division multiple access with time division multiple access technology for spread-spectrum communications. At a base station, a spread-spectrum transmitter includes a multiplexer for time multiplexing a synchronization-code signal and a plurality of data signals, which may be encoded as a plurality-encoded data signals, to generate a time-multiplexed signal. A chip code generator generates a chip-code signal which is modulo added with the time-multiplexed signal by an EXCLUSIVE-OR gate to generate a spread-spectrum-time-multiplexed signal. A transmitter transmits the spread-spectrum-time-multiplexed signal over a communications channel. A spread-spectrum receiver at the base station processes a plurality of spread-spectrum signals, received from a plurality of remote units in as time division sequence of spread-spectrum signals, using a despreader circuit to generate a time-division signal. A demultiplexer demultiplexes the time-division signal as a plurality of data signals or as a plurality of privacy-encoded data signals. A remote unit, which may be a handset, includes a despreader circuit for despreading the spread-spectrum-time-multiplexed signal as a time-multiplexed signal. A synchronization-code matched filter detects the synchronization-code signal embedded in the time-multiplexed signal and thereby generates a timing signal. A controller uses the timing signal to generate a control signal. The control signal controls a transmit-receive switch for switching an antenna between the despreader circuit to the transmitter at the remote unit.

Claims

1. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, f₀, comprising:

a plurality of privacy-code generators for generating a plurality of privacy-code signals, respectively;

a plurality of EXCLUSIVE-OR gates coupled to said plurality of privacy-code generators for modulo adding each of the respective plurality of privacy-code signals to each of the plurality of data signals to generate a plurality of privacy-encoded data signals, respectively;

a plurality of data buffers coupled to said plurality of EXCLUSIVE-OR gates for storing the plurality of privacy-encoded data signals, respectively;

a synchronization-code generator for generating a synchronization-code signal;

a synchronization buffer coupled to said synchronization-code generator for storing the synchronization-code signal;

a multiplexer coupled to said synchronization buffer and to said plurality of data buffers for time multiplexing the synchronization-code signal and the plurality of privacy-encoded-data signals, respectively, to generate a time-multiplexed signal;

p1 a chip-code generator for generating a chip-code signal;

an EXCLUSIVE-OR gate coupled to said multiplexer and to said chip-code generator, for spread-spectrum processing the time-multiplexed signal with the chip-code signal as a spread-spectrum-time-multiplexed signal; and

a transmitter for transmitting the spread-spectrum-time-multiplexed signal on the carrier frequency over a communications channel.

2. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:

base-synchronization means for generating a synchronization-code signal;

base-privacy means for encoding a plurality of data signals with a plurality of privacy-code signals as a plurality of privacy-encoded-data signals, respectively;

multiplexer means for time multiplexing the synchronization-code signal and the plurality of privacy-encoded-data signals, respectively, to generate a time-multiplexed signal;

base-spreading means for spread-spectrum processing the time-multiplexed signal with a chip-code signal to generate a spread-spectrum-time-multiplexed signal; and

base-transmitter means for converting the spread-spectrum-time-multiplexed signal to a form suitable for sending over a communications channel.

3. The spread-spectrum transmitter as set forth in claim 2 wherein said base-privacy means includes:

a plurality of privacy-code generators for generating the plurality of privacy-code signals, respectively; and

a plurality of EXCLUSIVE-OR gates for modulo adding each of the respective plurality of privacy-code signals to each of the plurality of data signals, respectively.

4. The spread-spectrum transmitter as set forth in claim 2 wherein said multiplexer means includes:

a plurality of data buffers for storing the plurality of privacy-encoded-data signals;

a synchronization buffer for storing the synchronization-code signal; and

a multiplexer for time multiplexing the synchronization-code signal and the plurality of privacy-encoded-data signals, respectively, to generate the time-multiplexed signal.

5. The spread-spectrum transmitter as set forth in claim 2 wherein said base-spreading means includes:

a chip-code generator for generating a chip-code signal; and

an EXCLUSIVE-OR gate for spread-spectrum processing the time-multiplexer signal with the chip-code signal to generate the spread-spectrum-time-multiplexer signal.

6. The spread-spectrum transmitter as set forth in claim 2 wherein said base-transmitter means includes:

an oscillator for generating a carrier frequency;

a product device for shifting the spread-spectrum-time-multiplexed signal to the carrier frequency;

a power amplifier for amplifying the spread-spectrum-time-multiplexed signal at the carrier frequency; and

an antenna for radiating the amplified spread-spectrum-time-multiplexed signal at the carrier frequency over the communications channel.

48. communications channel. 53. The spread-spectrum transmitter as set forth in claim .[.2.]. .Iadd.45.Iaddend., further including:

a plurality of base-privacy means for encoding the plurality of data signals with a plurality of privacy-code signals as a plurality of privacy-encoded-data signals, respectively; and

wherein said plurality of base-spreading means spread-spectrum processes the plurality of privacy-encoded-data signals with the plurality of chip-code signals to generate the plurality of spread-spectrum signals,

7. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:

.Iadd.a plurality of privacy-code generators for generating a plurality of privacy-code signals, respectively;

a plurality of EXCLUSIVE-OR gates for modulo adding each of the respective plurality of privacy-code signals to a respective one of the plurality of data signals to generate a plurality of privacy-encoded data signals;

.Iaddend.

synchronization means for generating a synchronization-code signal;

multiplexer means for time multiplexing the synchronization-code signal and the plurality of .Iadd.privacy-encoded .Iaddend.data signals, respectively, to generate a time-multiplexed signal;

spreading means for spread-spectrum processing the time-multiplexed signal with a chip-code signal to generate a spread-spectrum-time-multiplexed signal; and

transmitter means for converting the spread-spectrum-time-multiplexed signal to a form suitable for sending over a communications channel.

8. The spread-spectrum transmitter as set forth in claim 7 wherein said multiplexer means includes:

a plurality of data buffers .Iadd.coupled to said plurality of .[.EXCLUSIVE.]. .Iadd.ELUSIVE-OR .Iaddend.gates, respectively, for storing the plurality of .Iadd.privacy-encoded .Iaddend.data signals;

a synchronization buffer for storing the synchronization-code signal; and

a multiplexer for time multiplexing the synchronization-code signal and the plurality of .Iadd.privacy-encoded .Iaddend.data signals, respectively, to generate the time-multiplexed signal.

9. The spread-spectrum transmitter as set forth in claim 7 wherein said spreading means includes:

a chip-code generator for generating a chip-code signal; and

an EXCLUSIVE-OR gate for spread-spectrum processing the time-multiplexed signal with the chip-code signal as the spread-spectrum-time-multiplexed signal.

10. The spread-spectrum transmitter as set forth in claim 7 wherein said transmitter means includes:

an oscillator for generating a carrier frequency;

a product device for shifting the spread-spectrum-time-multiplexed signal to the carrier frequency;

a power amplifier for amplifying the spread-spectrum-time-multiplexed signal at the carrier frequency; and

an antenna for radiating the amplified spread-spectrum-time-multiplexed signal at the carrier frequency over a communications channel.

11. A spread-spectrum receiver for spread-spectrum processing a spread-spectrum-time-division signal, wherein the spread-spectrum-time-division signal includes a plurality of spread-spectrum signals received sequentially in time from a plurality of remote units, comprising:

a despreader circuit for despreading the spread-spectrum-time-division signal as a time-division signal;

a demultiplexer coupled to said despreader circuit for demultiplexing the time-division signal as a plurality of remote-privacy-encoded-data signals;

a synchronization-code generator for generating a synchronization-code signal;

a timing circuit coupled to said synchronization-code generator and responsive to the synchronization-code signal for generating a timing signal;

a plurality of privacy-code generators coupled to said timing circuit and responsive to the timing signal for generating a .Iadd.respective .Iaddend.plurality of remote-privacy-code signals; and

a plurality of EXCLUSIVE-OR gates coupled to said demultiplexer and to said plurality of privacy-code generators for decoding the plurality of remote-privacy-encoded-data signals, respectively, as a plurality of remote-data signals.

12. The spread-spectrum receiver as set forth in claim 11 wherein said despreader .[.means.]. .Iadd.circuit .Iaddend.includes a surface-acoustic-wave device for despreading the received spread-spectrum-time-division signal as the time-division signal.

13. The spread-spectrum receiver as set forth in claim 11 wherein said despreader .[.means.]. .Iadd.circuit .Iaddend.includes a tapped-delay-line matched filter for despreading the received spread-spectrum-time-division signal as the time-division signal.

14. The spread-spectrum receiver as set forth in claim 11 wherein said despreader .[.means.]. .Iadd.circuit .Iaddend.includes:

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

a mixer coupled to said chip-code generator and responsive to the chip-code signal for despreading the received spread-spectrum-time-division signal as the time-division signal; and

a filter coupled to said mixer for filtering the time-division signal. .[.

15. A spread-spectrum receiver for spread-spectrum processing a spread-spectrum-time-division signal, wherein the spread-spectrum-time-division signal includes a plurality of spread-spectrum signals received sequentially in time from a plurality of remote units, comprising:

despreader means for despreading the spread-spectrum-time-division signal as a time-division signal; and

demultiplexer means for demultiplexing the time-division signal as a plurality of remote-data signals..]..[.16. The spread-spectrum receiver as set forth in claim 15 wherein said despreader means includes a surface-acoustic-wave device for despreading the received spread-spectrum-time-division signal as the time-division signal..]..[.17. The spread-spectrum receiver as set forth in claim 15 wherein said despreader means includes a tapped-delay-line matched filter for despreading the received spread-spectrum-time-division signal as the time-division signal..]..[.18. The spread-spectrum receiver as set forth in claim 15 wherein said despreader means includes;

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

a mixer coupled to said chip-code generator and responsive to the chip-code signal for despreading the received spread-spectrum-time-division signal as the time-division signal; and

a filter coupled to said mixer for filtering the time-division signal..]..[.19. The spread-spectrum receiver as set forth in claim 15 wherein said demultiplexer means includes a demultiplexer for demultiplexing the time-division signal as the plurality of data

16. signals..].20. A spread-spectrum receiver for spread-spectrum processing a spread-spectrum-time-division signal, wherein the spread-spectrum-time-division signal includes a plurality of spread-spectrum signal received sequentially in time from a plurality of remote units, comprising:

base-despreader means for despreading the spread-spectrum-time-division signal as a time-division signal;

base-demultiplexer means for demultiplexing the time-division signal as a plurality of remote-privacy-encoded data signals;

base-synchronization means for generating a timing signal; and

base-decoder means responsive to the timing signal for decoding the plurality of remote-privacy-encoded signals as a plurality of remote-data

20. a filter coupled to said mixer for filtering the time-division signal. 24. The spread-spectrum receiver as set forth in claim 20 wherein said base-demultiplexer means includes a demultiplexer for demultiplexing the time-division signal as the plurality of privacy-encoded-data signals.

17. signals, respectively. 21. The spread-spectrum receiver as set forth in claim 20 wherein said base-despreader means includes a surface-acoustic-wave device for despreading the received

18. spread-spectrum-time-division signal as the time-division signal. 22. The spread-spectrum receiver as set forth in claim 20 wherein said base-despreader means includes a tapped-delay-line matched filter for despreading the received spread-spectrum-time-division signal as the

19. time-division signal. 23. The spread-spectrum receiver as set forth in claim 20 wherein said base-despreader means includes:

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

a mixer coupled to said chip-code generator and responsive to the chip-code signal for despreading the received spread-spectrum-time-division signal as the time-division signal; and

21. The spread-spectrum receiver as set forth in claim 20 wherein said base-synchronization means includes:

a synch-code generator for generating a synchronization code; and

a timing circuit responsive to the synchronization-code signal for

22. generating a timing signal. 26. The spread-spectrum-receiver as set forth in claim 20 wherein said base-decoder means includes:

a plurality of privacy-code generators responsive to the timing signal for generating a plurality of privacy-code signals.Iadd., respectively.Iaddend.; and

a plurality of EXCLUSIVE-OR gates for .[.the.]. decoding the plurality of privacy-encoded data signals as a plurality of data signals, respectively.

23. 7. A remote unit for receiving a spread-spectrum-time-multiplexed signal, having a synchronization signal and a plurality of privacy-encoded data signals including a first privacy-encoded-data signal, on a first carrier frequency, f₁, and for spread-spectrum transmitting a remote-data signal on a second carrier frequency, f₂, comprising:

an antenna;

a despreader circuit coupled to said antenna for despreading the spread-spectrum-time-multiplexed signal as a time-multiplexed signal;

a synchronization-code matched filter coupled to said despreader circuit and responsive to a synchronization-code signal embedded in the time-multiplexed signal for generating a timing signal;

a controller coupled to said synchronization-code matched filter and responsive to the timing signal for generating a control signal;

a first buffer coupled to said despreader circuit and to said controller, said first buffer responsive to the control signal for storing the first privacy-encoded-data signal embedded in the time-multiplexed signal;

a first privacy-code generator coupled to said controller and responsive to the control signal for generating a first privacy-code signal;

a first EXCLUSIVE-OR gate coupled to said first privacy-code generator and to said first buffer for decoding the first privacy-encoded-data signal as a first data signal;

a second privacy-code generator coupled to said controller and responsive to the control signal for generating a remote-privacy-code signal;

a second EXCLUSIVE-OR gate coupled to said second privacy-code generator for encoding the remote-data signal with the remote-privacy-code signal as a remote-privacy-encoded-data signal;

a second buffer for storing the remote-privacy-encoded-data signal;

a second chip-code generator for generating a second chip-code signal;

a third EXCLUSIVE-OR gate coupled to said second buffer and to said second chip-code generator for spread-spectrum processing the .[.remote-privacy-encoded.]. .Iadd.remote-privacy-encoded-data .Iaddend.signal with the second chip-code signal as a spread-spectrum .Iadd.encoded .Iaddend.signal;

a transmitter for transmitting the spread-spectrum encoded signal on the second carrier frequency, f₂ ; and

a transmit-receive switch responsive to the control signal for switching

27. a filter for filtering the time-multiplexed signal. 31. A remote unit for receiving a spread-spectrum-time-multiplexed signal, having a synchronization-code signal and a plurality of privacy-encoded data signals including a first privacy-encoded data signal, at a first carrier frequency, and for spread-spectrum transmitting a remote-data signal at a second carrier frequency, comprising:

remote-despreader means for despreading the spread-spectrum-time-multiplexed signal as a time-multiplexed signal;

remote-synchronization means responsive to the time-multiplexed signal for detecting the synchronization-code signal and generating a timing signal;

control means responsive to the timing signal for generating a control signal;

remote-decoder means responsive to the control signal for decoding the first privacy-encoded data signal embedded in the time-multiplexed signal as a first data signal;

remote-privacy means responsive to the control signal for encoding the remote-data signal with a remote-privacy-code signal as a remote-privacy-encoded data signal;

remote-spreading means for spread-spectrum processing the remote-privacy-encoded data signal with a second chip-code signal to generate a spread-spectrum signal; and

remote-transmitter means for converting the spread-spectrum signal to a

24. the antenna from the despreader circuit to the transmitter. 28. The remote unit as set forth in claim 27 wherein said despreader circuit includes a surface-acoustic-wave device for despreading the received spread-spectrum-time-multiplexed signal as the time-multiplexed signal.

25. The remote unit as set forth in claim 27 wherein said despreader circuit includes a .[.tapped-delay-live.]. .Iadd.tapped-delay-line .Iaddend.matched filter for despreading the received

26. spread-spectrum-time-multiplexed signal. 30. The remote unit as set forth in claim 27 wherein said despreader circuit includes:

a first chip-code .Iadd.generator for generating a first chip-code .Iaddend.signal;

a mixer coupled to said first chip-code generator and responsive to the first chip-code signal for despreading the received spread-spectrum-time-multiplexed signal as the time-multiplexed signal; and

31. a filter for filtering the time-multiplexed signal. 35. The remote unit as set forth in claim 31 wherein:

said remote-synchronization means includes a synchronization-matched filter responsive to the synchronization-code signal for generating the timing signal; and

said control means includes a controller responsive to the timing signal

28. form suitable for sending over a communications channel. 32. The remote unit as set forth in claim 31 wherein said remote-despreader means includes a surface-acoustic-wave device for despreading the spread-spectrum-time-multiplexer signal as the time-multiplexed signal.

29. The remote unit as set forth in claim 31 wherein said remote-despreader means includes a tapped-delay-time matched filter for despreading the spread-spectrum-time-multiplexed signal as the

30. time-multiplexed signal. 34. The remote unit as set forth in claim 31 wherein said remote-despreader means includes:

a first chip-code .Iadd.generator for generating a first chip-code .Iaddend.signal;

a mixer coupled to said first chip-code generator and responsive to the first chip-code signal for despreading the received spread-spectrum-time-multiplexed signal as the time-multiplexed signal; and

32. for generating the control signal. 36. The remote unit as set forth in claim 31 wherein said remote-decoder means includes:

a first buffer responsive to the control signal for storing the first privacy-encoded data signal embedded in the time-multiplexed signal;

a first-privacy-code generator responsive to the control signal for generating a privacy-code signal; and

a first EXCLUSIVE-OR gate for decoding the first privacy-encoded data

33. signal as the first data signal. 37. The remote unit as set forth in claim 31 wherein said remote-privacy means includes:

a second privacy-code generator responsive to the control signal for generating the remote-privacy-code signal; and

a second EXCLUSIVE-OR gate for encoding the remote-data signal with the

34. remote-privacy-code signal as the remote-privacy-encoded data signal. 38. The remote unit as set forth in claim 31 wherein said remote-spreading means includes:

a second buffer for storing the remote-privacy-encoded data signal;

a second chip-code generator for generating a second chip-code signal; and

a third EXCLUSIVE-OR gate for spread-spectrum processing the second privacy-encoded signal with the second chip-code signal as a

35. spread-spectrum signal. 39. The remote unit as set forth in claim 31 further including:

an antenna; and

a transmit-receive switch responsive to the control signal for switching the antenna from said .[.despreader.]. .Iadd.remote-despreader .Iaddend.means to said .[.transmitter.]. .Iadd.remote-transmitter

36. Iaddend.means. 40. A remote unit for receiving a spread-spectrum-time-multiplexed signal, having a synchronization-code signal and a plurality of data signals including a first data signal, at a first carrier frequency, and for spread-spectrum transmitting a remote-data signal at a second carrier frequency, comprising:

remote-despreader means for despreading the spread-spectrum-time-multiplexed signal as a time-multiplexed signal;

remote-synchronization means responsive to the time-multiplexed signal for detecting the synchronization-code signal and generating a control signal;

.Iadd.remote-privacy means responsive to the control signal for encoding the remote-data signal with a remote-privacy code signal as a remote-privacy-encoded-data signal;

.Iaddend.

remote-spreading means for spread-spectrum processing the .[.remote-data.]. .Iadd.remote-privacy-encoded-data .Iaddend.signal with a second chip-code signal as a spread-spectrum signal; and

remote-transmitter means for converting the spread-spectrum signal to a

40. a filter for filtering the time-multiplexed signal. 44. The remote unit as set forth in claim 40 wherein:

said remote-synchronization means includes a synchronization-matched filter responsive to the synchronization-code signal for generating .[.and.]. .Iadd.a .Iaddend.timing signal; and

further including control .Iadd.means, responsive to the .Iaddend.timing

37. form suitable for sending over a communications channel. 41. The remote unit as set forth in claim 40 wherein said remote-despreader means includes a surface-acoustic-wave device for despreading the spread-spectrum-time-multiplexed signal as the time-multiplexed signal.

38. The remote unit as set forth in claim 40 wherein said remote-despreader means includes a tapped-delay-time matched filter for despreading the spread-spectrum-time-multiplexed signal as the

39. time-multiplexed signal. 43. The remote unit as set forth in claim 40 wherein said remote-despreader means includes:

a first chip-code .Iadd.generator for generating a first chip-code .Iaddend.signal;

a mixer coupled to said first chip-code generator and responsive to the first chip-code signal for despreading the received spread-spectrum-time-multiplexed signal as the time-multiplexed signal; and

41. signal.Iadd., .Iaddend.for generating the control signal. 45. The remote unit as set forth in claim 40 wherein said remote-spreading means includes:

a second buffer for storing the .[.remote-data.]. .Iadd.remote-privacy-encoded-data .Iaddend.signal;

a second chip-code generator for generating .[.a.]. .Iadd.the .Iaddend.second chip-code signal; and

a third EXCLUSIVE-OR gate for spread-spectrum processing the .[.remote-data.]. .Iadd.remote-privacy-encoded data .Iaddend.signal with

42. the second chip-code signal to generate a spread-spectrum signal. 46. The remote unit as set forth in claim 40 further including:

an antenna; and

a transmit-receive switch responsive to the control signal for switching the antenna from said .[.despreader.]. .Iadd.remote-despreader .Iaddend.means to said .[.transmitter.]. .Iadd.remote-transmitter

43. Iaddend.means. 47. A method for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising the steps of:

generating a synchronization-code signal;

encoding a plurality of data signals with a plurality of privacy-code signals as a plurality of privacy-encoded data signals, respectively;

time multiplexing the synchronization-code signal and the plurality of privacy-encoded data signals, respectively, to generate a time-multiplexed signal;

spread-spectrum processing the time-multiplexed signal with a chip-code signal to generate a spread-spectrum-time-multiplexed signal; and

converting the spread-spectrum-time-multiplexed signal to a form suitable

44. for sending over a communications channel. .[.48. A method for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising the steps of:

generating a synchronization-code signal;

time-multiplexing the synchronization-code signal and the plurality of data signals, respectively, to generate a time-multiplexed signal;

spread-spectrum processing the time-multiplexed signal with a chip-code signal to generate a spread-spectrum-time-multiplexed signal; and

converting the spread-spectrum-time-multiplexed signal to a form suitable for sending over a communications channel..]..[.49. A method for receiving a spread-spectrum-time-multiplexed signal, comprising the steps of;

despreading the spread-spectrum-time-multiplexed signal as a time-multiplexed signal; and

demultiplexing the time-multiplexed signal as a plurality of data

45. signals..].50. A method for receiving a spread-spectrum-time-division signal, comprising the steps of:

despreading the spread-spectrum-time-division signal as time-division signal;

demultiplexing the time-division signal as a plurality of remote-privacy-encoded remote-data .[.signal.]. .Iadd.signals.Iaddend.;

generating a timing signal; and

decoding in response to the timing signal, the plurality of remote-privacy-encoded data signals as a plurality of remote-data signals.

46. 1. A method of receiving a spread-spectrum-time-multiplexed signal, having a .[.synchronization.]. .Iadd.synchronization-code .Iaddend.signal and a first privacy-encoded data signal, at a first carrier frequency, and for .[.a.]. spread-spectrum transmitting a remote-data signal at a second carrier frequency, .Iadd.comprising .Iaddend.the steps of:

despreading the spread-spectrum-time-multiplexed signal as a time-multiplexed signal;

detecting, in the time-multiplexed signal, the synchronization-code signal and generating a timing signal;

generating, in response to the timing signal, a control signal;

decoding .[.a.]. .Iadd.the .Iaddend.first privacy-encoded data signal embedded in the time-multiplexed signal as a first data signal;

encoding, in response to the control signal, the remote-data signal with a remote-privacy-code signal as a remote-privacy-encoded data signal;

spread-spectrum processing the remote privacy-encoded data signal with a .[.second.]. chip-code signal as a spread-spectrum signal; and

converting the spread-spectrum signal to a form suitable for sending over a

47. communications channel. 52. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:

base-synchronization means for generating a synchronization-code signal.Iadd.;

.Iaddend.

a plurality of base-spreading means for spread-spectrum processing the synchronization-code signal and the plurality of data signals .[.and.]. with a plurality of chip-code signals .Iadd., respectively, .Iaddend.to generate a spread-spectrum-processed-synchronization-code signal and a plurality of spread-spectrum signals.[., respectively.].;

combiner means for combining the plurality of spread-spectrum signals.[., respectively,.]. to generate a combined-spread-spectrum signal;

multiplexer means for time multiplexing the spread-spectrum-processed-synchronization-code signal and the combined-spread-spectrum signal as a multiplexed-spread-spectrum signal; and

base-transmitter means for converting the .[.time-multiplexed spread-spectrum.]. .Iadd.multiplexed-spread-spectrum .Iaddend.spread-spectrum signal to a form suitable for sending over a

52. multiplexed-spread-spectrum signal. 57. The spread-spectrum transmitter as set forth in claim 52 wherein said base-transmitter means includes:

an oscillator for generating a carrier frequency;

a product device for shifting the combined-spread-spectrum signal to the carrier frequency;

a power amplifier for amplifying the multiplexed-spread-spectrum signal at the carrier frequency; and

an antenna for radiating the amplified multiplexed-spread-spectrum signal

50. Iaddend.data .[.signal, respectively.]. .Iadd.signals.Iaddend.. 55. The spread-spectrum transmitter as set forth in claim .[.52.]. .Iadd.53 .Iaddend.wherein each of said .Iadd.plurality of .Iaddend.base-spreading means includes:

a chip-code generator for generating a chip-code signal; and

an EXCLUSIVE-OR gate for spread-spectrum processing .Iadd.a respective one of .Iaddend.the .Iadd.plurality of .Iaddend.privacy-encoded-data .[.signal.]. .Iadd.signals .Iaddend.with the chip-code signal to generate .Iadd.a respective one of .Iaddend.the .Iadd.plurality of

51. Iaddend.spread-spectrum .[.signal.]. .Iadd.signals.Iaddend.. 56. The spread-spectrum transmitter as set forth in claim 52 wherein said multiplexer means includes:

a first data buffer for storing the combined-spread-spectrum signal;

a second buffer for storing the spread-spectrum-processed-synchronization-code signal; and

a multiplexer for time multiplexing the spread-spectrum-processed-synchronization-code signal and the combined-spread-spectrum signal, respectively, to generate the

53. at the carrier frequency over the communications channel. 58. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:

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

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

combiner means for combining the generic-chip-code signal and the plurality of spread-spectrum signals, respectively, to generate a combined-spread-spectrum signal;

.[.and.].

base-transmitter means for converting the combined-spread-spectrum signal to a form suitable for sending over a communications channel.Iadd.;

a plurality of base-privacy means for encoding a plurality of data signals with a plurality of privacy-code signals as a plurality of privacy-encoded data signals, respectively; and

wherein said plurality of base-spreading means spread-spectrum processes the plurality of privacy-encoded-data signals with the plurality of chip-code signals to generate the plurality of spread-spectrum signals,

49. respectively. 54. The spread-spectrum transmitter as set forth in claim 53 wherein each of said .Iadd.plurality of .Iaddend.base-privacy means includes:

a privacy-code generator for generating .[.the.]. .Iadd.a .Iaddend.privacy-code signal; and

an EXCLUSIVE-OR gate for modulo-2 adding the .[.respective.]. privacy-code signal to .Iadd.a respective one of .Iaddend.the .Iadd.plurality of

54. respectively.Iaddend.. .[.59. The spread-spectrum transmitter as set forth in claim 58, further including:

a plurality of base-privacy means for encoding a plurality of data signals with a plurality of privacy-code signals as a plurality of privacy-encoded-data signals, respectively; and

wherein said plurality of base-spreading means spread-spectrum processes the plurality of privacy-encoded-data signals with the plurality of chip-code signals to generate the plurality of spread-spectrum signals,

55. respectively..].60. The spread-spectrum transmitter as set forth in claim .[.59.]. .Iadd.58 .Iaddend.wherein each of said .Iadd.plurality of .Iaddend.base-privacy means includes:

a privacy-code generator for generating .Iadd.a respective one of .Iaddend.the .Iadd.plurality of .Iaddend.privacy-code .[.signal, respectively.]. .Iadd.signals.Iaddend.; and

an EXCLUSIVE-OR gate for modulo-2 adding the respective privacy-code signal to .Iadd.a respective one of .Iaddend.the .Iadd.plurality of .Iaddend.data

56. [.signal, respectively.]. .Iadd.signals.Iaddend.. 61. The spread-spectrum transmitter as set forth in claim 58 wherein each of said .Iadd.plurality of .Iaddend.base-spreading means includes:

a chip-code generator for generating a respective chip-code signal; and

an EXCLUSIVE-OR gate for spread-spectrum processing .Iadd.a respective one of .Iaddend.the .Iadd.plurality of .Iaddend.privacy-encoded-data .[.signal.]. .Iadd.signals .Iaddend.with the .Iadd.respective .Iaddend.chip-code signal to generate .Iadd.a respective one of .Iaddend.the .Iadd.plurality of .Iaddend.spread-spectrum .[.signal,

57. respectively.]. .Iadd.signals.Iaddend.. 62. The spread-spectrum transmitter as set forth in claim 58 wherein .[.each of.]. said base-transmitter means includes:

an oscillator for generating a carrier frequency;

a product device for shifting the combined-spread-spectrum signal to the carrier frequency;

a power amplifier for amplifying the combined-spread-spectrum signal at the carrier frequency; and

an antenna for radiating the amplified combined-spread-spectrum signal at the carrier frequency over the communications channel.