CDMA/TDMA spread-spectrum communications system and method
First Claim
1. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, fo, 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;
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.
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Accused Products
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.
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Citations
62 Claims
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1. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, fo, comprising:
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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; 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.
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2. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:
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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. - View Dependent Claims (3, 4, 5, 6, 53, 54)
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7. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:
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synchronization means for generating a synchronization-code signal; multiplexer means for time multiplexing the synchronization-code signal and the plurality of 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. - View Dependent Claims (8, 9, 10)
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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:
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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 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. - View Dependent Claims (12, 13, 14)
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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:
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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. - View Dependent Claims (16, 17, 18, 19)
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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:
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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 signals, respectively. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. 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:
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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 signal with the second chip-code signal as a spread-spectrum 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 the antenna from the despreader circuit to the transmitter. - View Dependent Claims (28, 29, 30)
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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:
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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 form suitable for sending over a communications channel. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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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:
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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; remote-spreading means for spread-spectrum processing the remote-data signal with a second chip-code signal as a spread-spectrum signal; and remote-transmitter means for converting the spread-spectrum signal to a form suitable for sending over a communications channel. - View Dependent Claims (41, 42, 43, 44, 45, 46)
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47. A method for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising the steps of:
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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 for sending over a communications channel.
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48. A method for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising the steps of:
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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.
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49. A method for receiving a spread-spectrum-time-multiplexed signal, comprising the steps of:
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despreading the spread-spectrum-time-multiplexed signal as a time-multiplexed signal; and demultiplexing the time-multiplexed signal as a plurality of data signals.
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50. A method for receiving a spread-spectrum-time-division signal, comprising the steps of:
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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; 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.
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51. A method of receiving a spread-spectrum-time-multiplexed signal, having a synchronization 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, the steps of:
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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 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 communications channel.
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52. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:
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base-synchronization means for generating a synchronization-code signal 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 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 signal to a form suitable for sending over a communications channel. - View Dependent Claims (55, 56, 57)
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58. A spread-spectrum transmitter for spread-spectrum processing a plurality of data signals on a carrier frequency, comprising:
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base-generic 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. - View Dependent Claims (59, 60, 61, 62)
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Specification