Spread spectrum communication apparatus

• US 5,737,329 A
• Filed: 04/12/1996
• Issued: 04/07/1998
• Est. Priority Date: 04/14/1995
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Horiguchi, Yoshinori
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): VU, HUY DUY
• Application Number:
  US08/631,199
• Time in Patent Office: 725 Days
• Field of Search: 370/320, 370/335, 370/342, 370/350, 370/441, 370/465, 370/479, 370/503, 370/507, 370/516, 370/517, 370/518, 370/519, 370/522, 370/203, 370/208, 370/209, 375/200, 375/205, 375/206, 375/207, 375/208, 375/209, 375/210, 375/340, 375/354, 375/356, 375/357, 375/358, 375/371, 375/373, 375/375, 375/376, 375/362, 375/364, 375/365, 375/367, 375/368, 455/67.6, 455/67.7, 455/68, 455/69, 455/70, 455/92, 455/133, 455/137, 455/139, 455/352
• US Class Current: 370/342
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/10 Code generation

Abstract

A spread spectrum communication apparatus for transmitting multiple signals such that signals transmitted from several transmitter-receivers can have the same PN code and yet not interfere with each other. A phase controller is used to control the phases of the PN codes from multiple transmitters so that the PN code phase is different for each transmitter. Thus, even though the same PN codes are transmitted, they all have different phases to prevent interference. This arrangement reduces the number of PN codes needed since only one PN code generator is needed for several receiver blocks.

Claims

1. A spread spectrum communication apparatus, comprising:

a first transmitter-receiver having;

a receiver block for receiving a transmission signal which is spread spectrum modulated using a first PN code, carrying out a spread spectrum demodulation by synchronizing the received signal with a phase of the first PN code, determining whether the spread spectrum demodulated signal has synchronized with the phase of the first PN code, and then outputting a synchronization detection signal;

a control signal generator for generating a control signal for shifting the phase of the first PN code for spread spectrum modulation in a second transmitter-receiver so as to establish synchronization of signals received in the receiver block of the first transmitter-receiver based on the synchronization detection signal; and

a transmitter block for transmitting to the second transmitter-receiver an information signal which is multiplexed with the control signal and spread spectrum modulated using a second PN code;

the second transmitter-receiver having;

a receiver block for receiving the transmission signal which is spread spectrum modulated in the first transmitter-receiver with the first PN code, performing a reverse spread spectrum process on the signal received by the receiver block in the second transmitter-receiver by synchronizing the phase of the received signal using the second PN code, demodulating the received signal, separating the control signal from the received signal and outputting control signal;

a phase controller for generating a phase control signal that shifts the phase of the first PN code for spread spectrum processing to establish a reception synchronization of the first transmitter-receiver, which can not establish the reception synchronization based on the control signal separated from the receiver block;

a transmitter block for transmitting an information signal for transmission by performing spread spectrum processing using the first PN code which is generated by a clock pulse synchronizing the phase of the first PN code with the spread spectrum demodulator of the receiver block; and

a phase shifter connected between the receiver block and the transmitter block of the second transmitter-receiver for shifting the phase of the first PN code based on the phase control signal from the phase controller in the second transmitter-receiver so as to establish the reception synchronization of the first transmitter-receiver.

6. A spread spectrum communication apparatus as claimed in claim 1, 2 or 4 wherein the phase shifter for shifting the first PN code phase of the second transmitter-receiver includes means for shifting a phase dispersively.

7. A spread spectrum communication apparatus as claimed in any one of claims 1 through 5, wherein the phase shifter for shifting the first PN code phase of the second transmitter-receiver includes means for shifting a phase continuously.

8. A spread spectrum communication apparatus as claimed in any one of claims 1 through 5, wherein the phase shifter for shifting the first PN code phase of the second transmitter-receiver includes means for shifting a phase continuously.

9. A spread spectrum communication apparatus as claimed in any one of claims 1 through 5, wherein the same frequency bands are adopted for the transmission and the reception of both the first and the second transmitter-receivers.

10. A spread spectrum communication apparatus as claimed in any one of claims 1 through 5, wherein different frequency bands are adopted for the transmission and the reception of both the first and the second transmitter-receivers.

2. A spread spectrum communication apparatus, comprising:

a first demodulator for receiving a transmission signal, which is a source identification signal multiplexed on an information signal and processed in a spread spectrum operation, and performing a reverse spread spectrum operation on the signal received by the first demodulator through synchronization with a phase of a first PN code;

a first synchronization detector connected to the first demodulator for detecting whether the signal received by the first demodulator is synchronized in phase with the first PN code;

a first receiver block connected to the first demodulator, the first receiver block having an identification signal separator for separating the identification signal from the signal received by the first demodulator;

a control signal generator for generating a control signal to control the phase of a second transmitter-receiver, which can not establish reception synchronization based on the first synchronization detector and the identification signal separator;

a control signal multiplexing means for multiplexing the control signal with a first information signal for transmission;

a second PN code generator for generating a second PN code using a fixed frequency clock;

a first transmitter-receiver which is equipped with a first transmitter block having a first modulator for performing spread spectrum processing of the first information signal for transmission to which the control signal is multiplexed using the second PN code;

a second demodulator for receiving the transmission signal which is spread spectrum processed in the first transmitter-receiver and performing a reverse spread spectrum operation on the signal received by the second demodulator through synchronization with a phase of the second PN code;

a second synchronization detector for detecting whether the signal received by the second demodulator is synchronized with, the second PN code;

a second receiver block having a control signal separator for separating a control signal from the signal received by the second demodulator;

a phase controller for generating a phase control signal to control the phase of the first PN code for spread spectrum modulation based on the second synchronization detector and the control signal separator;

an identification signal generator for generating the identification signal indicating the transmitting source to the first transmitter-receiver;

an identification signal multiplexing means for multiplexing the identification signal with a second information signal for transmission;

a first PN code generator for generating the first PN code using a clock pulse synchronizing the phase with the second demodulator;

a second transmitter-receiver which is equipped with a second transmitter block having a multiplier for performing spread spectrum processing of the second information signal for transmission to which the identification signal is multiplexed using the first PN code; and

a phase shifter connected between the first PN code generator, a second modulator and the phase controller for shifting the phase of the first PN code based on the phase control signal to establish the reception synchronization of the first transmitter-receiver.

3. A spread spectrum communication apparatus, comprising:

a first demodulator for receiving a transmission signal, which is a source identification signal multiplexed on an information signal and processed in a spread spectrum operation, and performing a reverse spread spectrum operation on the signal received by the first demodulator through synchronization with a phase of a first PN code;

a first synchronization detector connected to the first demodulator for detecting whether the signal received by the first demodulator is synchronized in phase with the first PN code;

a first receiver block connected to the first demodulator, the first receiver block having an identification signal separator for separating the identification signal from the signal received by the first demodulator;

a first phase shifter connected to the first demodulator for shifting the phase of the first PN code;

a first multiplier for performing reverse spread spectrum processing by inputting the signal received by the first demodulator and multiplying the signal received by the first demodulator with a first PN code whose phase is shifted in the first phase shifter;

a second synchronization detector connected to the first multiplier for detecting whether the signal received by the first multiplier is synchronized in phase with the shifted phase of the first PN code;

a second receiver block connected to the first multiplier, the second receiver block having a second identification signal separator for separating an identification signal from the signal received by the first demodulator;

a control signal generator for generating a control signal to control the phase of the second transmitter-receiver, which can not establish the reception synchronization based on the first and the second synchronization detectors and the first and the second identification signal separators;

a control signal multiplexing means for multiplexing the control signal with a first information signal for transmission;

a second PN code generator for generating a second PN code using a fixed frequency clock;

a first transmitter-receiver which is equipped with a first transmitter block having a first modulator for performing spread spectrum processing of the first information signal to which the control signal is multiplexed using the second PN code;

a third demodulator for receiving the transmission signal which is spread spectrum processed in the first transmitter-receiver and performing a reverse spread spectrum operation on the signal received by the second demodulator with a phase of the second PN code;

a third synchronization detector for detecting whether the signal received by the third demodulator synchronizes with the second PN code;

a third receiver block having a control signal separator for separating the control signal from the signal received by the third demodulator;

a phase controller for generating a phase control signal to control the phase of the first PN code for spread spectrum modulation based on the third synchronization detector and the control signal separator;

an identification signal generator for generating the identification signal for showing the transmitting source to the first transmitter-receiver;

an identification signal multiplexing means for multiplexing the identification signal with a second information signal for transmission;

a first PN code generator for generating the first PN code by a clock pulse synchronizing the phase with the third demodulator;

a second transmitter-receiver which is equipped with a second transmitter block having a second multiplier for performing spread spectrum processing of the second information signal to which the identification signal is mutiplexed using the first PN code, and

a second phase shifter connected between the first PN code generator, a second modulator and the phase controller for shifting the phase of the first PN code based on the phase control signal to establish the reception synchronization of the first transmitter-receiver.

4. A spread spectrum communication apparatus, comprising:

a first demodulator for receiving a transmission signal, which is a source identification signal multiplexed on an information signal and processed in a spread spectrum operation, and performing a reverse spread spectrum operation on the signal received by the first demodulator through synchronization with a phase of a first PN code;

a first synchronization detector connected to the first demodulator for detecting whether the signal received by the first demodulator is synchronized in phase with the first PN code;

a first receiver block connected to the first demodulator, the first receiver block having an identification signal separator for separating the identification signal from the signal received by the first demodulator;

a control signal generator for generating a control signal to control the phase of the second transmitter-receiver, which can not establish the reception synchronization based on the first synchronization detector and the identification signal separator;

a first control signal multiplexing means for multiplexing the control signal with a first information signal for transmission;

a second PN code generator for generating a second PN code by using a fixed frequency clock;

a first transmitter block having a first modulator for performing spread spectrum processing of a second information signal for transmission to which the control signal is multiplexed using the second PN code;

a first phase shifter for shifting the second PN code, the first phase shifter being connected to a second control signal multiplexing means for multiplexing the control signal to the second information signal for transmission and to the second PN code generator;

a first transmitter-receiver which is equipped with second transmitter blocks having a second modulator which performs spread spectrum processing by inputting the second information signal for transmission to which the control signal is multiplexed in the second control signal multiplexing means and multiplying the second information signal for transmission with the second PN code whose phase is shifted in the first phase shifter;

a second demodulator for receiving the transmission signal which is spread spectrum processed in the first transmitter-receiver and performing a reverse spread spectrum operation on the signal received by the second demodulator through synchronization with a phase of the second PN code;

a second synchronization detector for detecting whether the signal received by the second demodulator is synchronized with the second PN code;

a second receiver block having a control signal separator for separating the control signal from the signal received by the second demodulator;

a phase controller for generating a phase control signal to control the phase of the first PN code for spread spectrum modulation based on the second synchronization detector and the control signal separator;

an identification signal generator for generating the identification signal indicating the transmitting source to the first transmitter-receiver;

an identification signal multiplexing means for multiplexing the identification signal with a second information signal for transmission;

a first PN code generator for generating the first PN code using a clock pulse synchronizing the phase with the second demodulator;

a second transmitter-receiver which is equipped with a third transmitter block having a multiplier for performing spread spectrum processing of the second information signal for transmission to which the identification signal is multiplexed using the first PN code; and

a second phase shifter connected to the first PN code generator, the multiplier and the phase controller for shifting the phase of the first PN code based on the phase control signal to establish the reception synchronization of the first transmitter-receiver.

5. A spread spectrum communication apparatus, comprising:

a first demodulator for receiving a transmission signal, which is a source identification signal multiplexed on an information signal and processed in a spread spectrum operation, and performing a reverse spread spectrum operation on the signal received by the first demodulator through synchronization with a phase of a first PN code;

a first synchronization detector connected to the first demodulator for detecting whether the signal received by the first demodulator is synchronized in phase with the first PN code;

a first receiver block connected to the first demodulator, the first receiver block having an identification signal separator for separating the identification signal from the signal received by the first demodulator;

a first phase shifter connected to the first demodulator for shifting the phase of the first PN code;

a first multiplier for performing reverse spread spectrum processing by inputting the signal received by the first demodulator and multiplying the signal received by the first demodulator with a first PN code whose phase is shifted in the first phase shifter;

a second synchronization detector connected to the second demodulator for detecting whether the signal received by the first multiplier is synchronized in phase with the shifted phase of the first PN code;

a second receiver block connected to the first multiplier having a second identification signal separator for separating an identification signal from the signal received by the first multiplier;

a control signal generator for generating a control signal to control the phase of a second transmitter-receiver, which can not establish the reception synchronization based on the first and the second synchronization detector and the first and the second identification signal separator;

a first control signal multiplexing means for multiplexing the control signal with a first information signal for transmission;

a second PN code generator for generating a second PN code using a fixed frequency clock;

a first transmitter block having a second multiplier for performing spread spectrum processing of the first information signal to which the control signal is multiplexed using the second PN code;

a second control signal multiplexing means for multiplexing the control signal to a second information signal for transmission;

a second phase shifter connected to the second PN code generator for shifting the phase of the second PN code;

a first transmitter-receiver which is equipped with second transmitter blocks having the second multiplier for performing spread spectrum processing by inputting the first information signal for transmission, to which the control signal is multiplexed, in the second control signal multiplexing means and multiplying the first information signal with the second PN code whose phase is shifted in the second phase shifter;

a third demodulator for receiving the transmission signal which is spread spectrum processed in the first transmitter-receiver and performing a reverse spread spectrum operation on the signal received by the second demodulator through synchronization with a phase of the second PN code;

a third phase shifter for shifting the phase of the second PN code;

a third synchronization detector for detecting whether the signal received by the third demodulator is synchronized in phase with the second PN code;

a third receiver block having a control signal separator for separating a control signal from the signal received by the third demodulator;

a phase controller for generating a phase control signal to control the phase of the first PN code for spread spectrum modulation based on the third synchronization detector and the control signal separator;

an identification signal generator for generating the identification signal for showing the transmitting source to the first transmitter-receiver;

an identification signal multiplexing means for multiplexing the identification signal with a third information signal for transmission;

a first PN code generator for generating the first PN code by a clock pulse synchronizing the phase with the third demodulator;

a second transmitter-receiver which is equipped with a third transmitter block having a third multiplier for performing spread spectrum processing of the third information signal for transmission to which the identification signal is multiplexed using the first PN code,

wherein the third phase shifter is connected to the phase control means for shifting the phase of the second PN code based on the phase control signal output from the third receiver block to select and receive one of the signals transmitted from the second transmitter blocks; and

a fourth phase shifter connected to the first PN code generator, the third multiplier and the phase controller for shifting the phase of the first PN code based on the phase control signal to establish the reception synchronization of the first transmitter-receiver.