Spread spectrum communication apparatus and telephone exchange system

• US 5,467,367 A
• Filed: 06/13/1994
• Issued: 11/14/1995
• Est. Priority Date: 06/07/1991
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Izumi, Michihiro, Watanabe, Kazunari
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/259,122
• Time in Patent Office: 519 Days
• Field of Search: 375/200-210, 370/18, 380/31, 380/33, 380/34, 379/219, 379/220, 379/258, 379/268
• US Class Current: 375/142
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04J 13/0077 Multicode, e.g. multiple codes assigned to one user
• CPC Class Codes: H04J 13/10 Code generation

Abstract

A telephone exchange system of this invention has a terminal connected to an extension by radio. As a radio communication modulation method, a spread spectrum method is used. A speech signal received from a line by the telephone exchange system is exchanged by an exchange switch, and is supplied to a data conversion unit. The data conversion unit causes a serial/parallel converter to covert a serial input signal into a parallel signal. The converted parallel signal is subjected to spread-spectrum modulation in units of parallel bits. The modulated signal bits are added to each other by an adder, and the sum signal is multiplexed on a carrier signal. The multiplexed signal is transmitted to the terminal. Upon reception of the signal, the terminal causes a phase synchronization circuit to generate an inverse spread code corresponding to a spread code, and synchronized with the reception signal, and inversely spreads the reception signal using the generated inverse spread code. The inversely spread signal is converted into a serial signal by a parallel/serial converter, i.e., is demodulated into a speech signal. When a signal is transmitted from the terminal, the said procedure as described above is executed in the opposite direction.

Claims

1. A spread spectrum communication apparatus comprising:

generation means for generating a plurality of different spread codes in parallel;

modulation means for modulating transmission information of parallel bits using the plurality of spread codes generated by said generation means; and

transmission means for transmitting the transmission information modulated by said modulation means,

wherein said modulation means modulates each bit of the parallel bits using each of the plurality of spread codes in parallel.

2. The apparatus according to claim 1, wherein said generation means comprises a plurality of delay means having different delay times, and supplies a common spread code to said plurality of delay means to generate a plurality of spread codes having different phases.

3. The apparatus according to claim 1, wherein said generation means further generates a synchronization spread code, and said transmission means multiplies the signal accumulated by said accumulation means with the synchronization spread code generated by said generation means, and transmits the product signal.

4. The apparatus according to claim 3, wherein said generation means generates the synchronization spread code having the same length as that of the plurality of spread codes.

5. The apparatus according to claim 1, further comprising conversion means for converting serial data into parallel data, and wherein said modulation means modulates parallel data converted by said conversion means.

6. The apparatus according to claim 1, further comprising conversion means for converting serial transmission information into the transmission information of the parallel bits.

7. A spread spectrum communication apparatus comprising:

reception means for receiving a reception signal;

generation means for generating a plurality of different despread codes in parallel;

demodulation means for demodulating the reception signal using the plurality of despread codes generated by said generation means, respectively; and

conversion means for converting the reception signal demodulated by said demodulation means into parallel bits.

8. The apparatus according to claim 7, wherein said generation means comprises a plurality of delay means having different delay times, and supplies a common inverse spread code to said plurality of delay means to generate a plurality of inverse spread codes having different phases.

9. The apparatus according to claim 7, wherein said generation means comprises means for generating a synchronization spread code in synchronism with the plurality of inverse spread codes, and correlation means for checking a correlation between the synchronization spread code and a reception signal, and generates the plurality of inverse spread codes according to the correlation between the synchronization spread code and the reception signal.

10. The apparatus according to claim 9, wherein said generation means generates the synchronization spread code having the same length as that of the plurality of inverse spread codes.

11. The apparatus according to claim 7, further comprising conversion means for converting parallel data into serial data, said conversion means converting a parallel signal demodulated by said demodulation means into a serial signal.

12. A spread spectrum transmission apparatus comprising:

generation means for generating a plurality of spread codes;

demultiplexing means for demultiplexing transmission information, generated by multiplexing data from a plurality of channels, to data from each of the plurality of channels;

spread means for spreading the data from each of the plurality of channels demultiplexed by said demultiplexing means on the basis of the plurality of spread codes generated by said generation means; and

transmission means for transmitting the data from the plurality of channels spread by said spread means.

13. The apparatus according to claim 12, further comprising conversion means for converting serial transmission information into the transmission information consisting of the plurality of bits.

14. The apparatus according to claim 12, wherein said demultiplexing means demultiplexes information from a digital network.

15. The apparatus according to claim 12, wherein said demultiplexing means demultiplexes information from a digital terminal.

16. A spread spectrum reception apparatus comprising:

reception means for receiving a reception signal;

generation means for generating a plurality of despread codes;

a plurality of despread means for despreading the reception signal on the basis of the plurality of despread codes generated by said generation means, respectively;

supply means for supplying the reception signal to said plurality of despread means; and

conversion means for converting a plurality of outputs of the plurality of despread means into parallel data.

17. The apparatus according to claim 16, wherein said supply means supplies the reception signal to the plurality of despread means in parallel.

18. A spread spectrum communication apparatus comprising:

first generation means for generating a first spread code;

a plurality of delay means for delaying the first spread code to generate a plurality of spread codes having different phases;

modulation means for modulating transmission information signals of a plurality of parallel channels using the plurality of spread codes generated by said plurality of delay;

accumulation means for accumulating the signals of the channels modulated by said modulation means;

second generation means for generating a second spread code;

multiplication means for multiplying a signal accumulated by said accumulation means with the second spread code generated by said second generation means; and

transmission means for transmitting the signal multiplied by said multiplication means.

19. A spread spectrum communication apparatus comprising:

first generation means for generating a first inverse spread code;

second generation means for generating a second inverse spread code;

correlation means for checking a correlation between the second inverse spread code and a reception signal;

third generation means for delaying the first inverse spread code according to the correlation between the second inverse spread code and the reception signal to generate a plurality of inverse spread codes having different phases; and

modulation means for parallelly modulating the reception signal using the plurality of inverse spread codes generated by said third generation means.

20. A telephone exchange system having an extension connected by radio, comprising:

reception means for receiving a signal from a terminal;

demodulation means for despreading the signal received by said reception means to demodulate the signal into a speech signal;

exchange means for exchanging the speech signal demodulated by said demodulation means;

transmission means for transmitting the speech signal exchanged by said exchange means to a communication partner; and

control means for controlling said exchange means on the basis of the signal received by said reception means.

21. The system according to claim 20, wherein said demodulation means despreads the reception signal using a plurality of inverse spread codes.

22. The system according to claim 21, wherein said demodulation means converts the data despread by the plurality of inverse spread codes into serial data, and outputs the serial data.

23. The system according to claim 21, wherein said demodulation means converts the data despread by the plurality of inverse spread codes into Alternate Mark Inversion code data, and outputs the Alternate Mark Inversion code data.

24. A telephone exchange system having an extension connected by radio, comprising:

receiving means for receiving a speech signal from a communication partner;

exchange means for exchanging the speech signal received by said receiving means;

spread means for spreading the speech signal exchanged by said exchange means; and

transmission means for transmitting the signal spread by said means to a terminal.

25. The system according to claim 24, wherein said transmission means spreads the speech signal using a plurality of spread codes.

26. The system according to claim 25, wherein said transmission means converts the speech signal into parallel data, and spreads channels of the parallel data using a plurality of different spread codes, respectively.

27. The system according to claim 25, wherein said transmission means demultiplexes a speech signal coded by Alternate Mark Inversion in units of channels, and spreads the demultiplexed data using different spread codes in units of channels.

28. A telephone exchange system having an extension connected by radio, comprising:

reception means for receiving a signal;

demodulation means for despreading the signal received by said reception means to demodulate the signal into a speech signal;

exchange means for exchanging the speech signal;

control means for controlling said exchange means on the basis of the signal received by said reception means;

spread means for spreading the speech signal exchanged by said exchange means; and

transmission means for transmitting the signal spread by said spread means.

29. A telephone exchange system connected to a plurality of mobile terminals by radio, comprising:

selection means for selecting one of a plurality of spread codes;

information means for informing the spread code selected by said selection means to one of the plurality of mobile terminals by radio;

demodulation means for despreading the signal from the mobile terminal informed by said information means in accordance with the spread code selected by selection means to demodulate the signal into a speech signal; and

transmission means for transmitting the speech signal to a communication partner.

30. The system according to claim 29, wherein said selection means comprises storage means for storing use conditions of the plurality of spread codes, and looks up said storage means to select an unused spread code.

31. A telephone exchange system connected to a plurality of mobile terminals by radio, comprising:

selection means for selecting one of a plurality of spread codes;

receiving means for receiving a speech signal from a communication partner;

exchange means for exchanging the speech signal received by said receiving means;

modulation means for modulating the speech signal exchanged by said exchange means in accordance with the spread code selected by said selection means; and

transmission means for transmitting the signal modulated by said modulation means.

32. A spread spectrum communication apparatus comprising:

storage means for storing a plurality of sets of spread codes;

selection means for selecting one set of the plurality of sets of spread codes stored in said storage means; and

communication means for performing a communication on the basis of the set of spread codes selected by said selection means.

33. The apparatus according to claim 32, wherein said selection means comprises reception means for receiving a selection signal for selecting one set of the plurality of sets of spread codes.

34. The apparatus according to claim 32, wherein said selection means comprises second storage means for storing data indicating whether or not each of the plurality of sets of spread codes is in use, and selects a spread code, corresponding data of which is stored in said second storage means to indicate that the spread code is not in use.

35. A spread spectrum transmission apparatus comprising:

generation means for generating a plurality of different spread codes in parallel corresponding to parallel bits of transmission information;

a plurality of modulation means for modulating parallel bits of transmission information using spread codes generated by said generation means;

transmission means for transmitting output of said plurality of modulation means;

wherein each of said plurality of modulation means modulates each bit of the parallel bits of transmission information using each of the plurality of spread codes.

36. A spread spectrum communication apparatus comprising:

reception means for receiving a reception signal;

generation means for generating a plurality of different despread codes in parallel;

demodulation means for demodulating the reception signal using the plurality of despread codes generated by said generation means, to output a plurality of demodulated signals corresponding to the plurality of despread codes;

multiplexing means for multiplexing the plurality of demodulated signals demodulated by said demodulation means to output a multiplexed signal; and

transmission means for transmitting the multiplexed signal multiplexed by said multiplexing means via a digital signal line.

37. The apparatus according to claim 36, wherein said transmission means transmits the multiplexed signal to a digital network via the digital signal line.

38. The apparatus according to claim 36, wherein said transmission means transmits the multiplexed signal to a digital terminal via the digital signal line.