MIXED VOICE AND SPREAD SPECTRUM DATA SIGNALING WITH MULTIPLEXING MULTIPLE USERS WITH CDMA

• US 20070047626A1
• Filed: 09/28/2006
• Published: 03/01/2007
• Est. Priority Date: 06/08/2005
• Status: Active Grant

• Current Assignee: Polycom Incorporated (Plantronics, Inc.), Salesforce.com, Inc.
• Original Assignee: Polycom Incorporated (Plantronics, Inc.)
• Inventors: ELIAS, ERIC
• Granted Patent: US 7,796,565 B2
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision

Abstract

Systems, methods, and devices for mixed voice and spread spectrum data signaling with spread spectrum data hiding with CDMA (Code Division Multiple Access) for three or more users. The disclosed systems, methods, and devices may be implemented in audio conferencing or video conferencing. Various embodiments of the present disclosure provide a data and voice mixer, which includes an improved spread spectrum data hiding transmitter. The transmitter may comprise a CDMA chip sequence generator and a spreading encoder. Different users may be accommodated by selecting different initializations for the registers of the CDMA chip sequence generator. Different spreading code may be used for different users which are near orthogonal to each other. In some embodiments, the CDMA chip sequence generator pseudo-randomly selects the chip sequence from one of a plurality of Gold chip sequence generators.

Claims

1. A method of exchanging analog signals and a digital data among at least two transmitters and at least one receiver in a teleconferencing system, the method comprising:

by a first transmitter, generating a first CDMA chip sequence;

combining a first digital bit stream and the first CDMA chip sequence, to form a first spread spectrum sequence;

modulating the first spread spectrum sequence onto a first analog signal, to form a first modulated signal;

transmitting the first modulated signal to the receiver via a first communication channel;

by a second transmitter, generating a second CDMA chip sequence;

combining a second digital bit stream and the second CDMA chip sequence, to form a second spread spectrum sequence;

modulating the second spread spectrum sequence onto a second analog signal, to form a second modulated signal; and

transmitting the second modulated signal to the receiver via a second communication channel;

wherein the first CDMA chip sequence is different from the second CDMA chip sequence.

2. The method of claim 1, wherein the act of generating the first CDMA chip sequence comprises periodically pseudo-randomly selecting the first CDMA chip sequence from one of a plurality of chip sequence generators.

3. The method of claim 2, wherein the plurality of chip sequence generators comprise at least four Gold chip sequence generators.

4. The method of claim 1, wherein the first CDMA chip sequence is orthogonal to the second CDMA chip sequence.

5. The method of claim 1, wherein the first analog signal comprises an audio signal.

6. The method of claim 1, wherein the first analog signal comprises a video signal.

7. The method of claim 1, wherein the first communication channel comprises a telephone channel.

8. The method of claim 1, wherein the first communication channel comprises a radio channel.

9. The method of claim 1, further comprising:

by the at least one receiver, demodulating a received signal, to produce a demodulated signal;

generating a third CDMA chip sequence;

generating a fourth CDMA chip sequence;

multiplying the demodulated signal by the third CDMA chip sequence, to reconstruct the first digital bit stream; and

multiplying the demodulated signal by the fourth CDMA chip sequence, to reconstruct the second digital bit stream;

wherein the third CDMA chip sequence is different from the fourth CDMA chip sequence.

10. A machine-readable medium having embodied thereon a program, the program being executable by a machine to perform the method of any of claim 1.

11. A conferencing endpoint, comprising:

at least one signal source;

a signal and data mixer communicably coupled to the at least one signal source, the signal and data mixer comprising;

a first CDMA chip sequence generator operable to generate a first CDMA chip sequence;

a spreading encoder operable to combine a digital bit stream and the first CDMA chip sequence, to form a first spread spectrum sequence; and

a modulator operable to modulate the spread spectrum sequence onto an analog signal received from the at least one signal source, to form a modulated signal for transmission via a communication channel;

at least one signal sink; and

a signal and data separator communicably coupled to the at least one signal sink, the signal and data separator comprising;

a demodulator operable to demodulate a signal received via the communication channel, to produce a demodulated signal;

a second CDMA chip sequence generator, operable to generate a second CDMA chip sequence;

a third CDMA chip sequence generator, operable to generate a third CDMA chip sequence;

a first spreading decoder operable to multiply the demodulated signal by the second CDMA chip sequence, to reconstruct a first digital bit stream;

a second spreading decoder operable to multiply the demodulated signal by the third CDMA chip sequence, to reconstruct a second digital bit stream; and

wherein the second CDMA chip sequence is different from the third CDMA chip sequence.

12. The endpoint of claim 11, wherein the first CDMA chip sequence is periodically pseudo-randomly selected from one of a plurality of chip sequence generators.

13. The endpoint of claim 12, wherein the plurality of chip sequence generators comprise at least four Gold chip sequence generators.

14. The endpoint of claim 11, wherein the at least one signal source comprises a microphone.

15. The endpoint of claim 11, wherein the at least one signal source comprises a video camera.

16. The endpoint of claim 11, wherein the at least one signal sink comprises a speaker.

17. The endpoint of claim 11, wherein the at least one signal sink comprises a display device.

18. The endpoint of claim 11, wherein the communication channel comprises a Plain Old Telephone System channel.

19. The endpoint of claim 11, wherein the communication channel comprises a radio channel.

20. A conferencing system for exchanging digital data and analog signals among at least three geographically remote endpoints, comprising:

a first endpoint comprising;

a first signal source; and

a first signal and data mixer communicably coupled to the first signal source, the first signal and data mixer comprising;

a first CDMA chip sequence generator operable to generate a first CDMA chip sequence;

a first spreading encoder operable to combine the first CDMA chip sequence and a first digital bit stream provided by a first data source, to form a first spread spectrum sequence; and

a first modulator operable to modulate the first spread spectrum sequence onto a first analog signal received from the first signal source, to form a first modulated signal for transmission to a conference bridge via a first communication channel;

a second endpoint comprising;

a second signal source; and

a second signal and data mixer communicably coupled to the second signal source, the second signal and data mixer comprising;

a second CDMA chip sequence generator operable to generate a second CDMA chip sequence;

a second spreading encoder operable to combine the second CDMA chip sequence and a second digital bit stream provided by a second data source, to form a second spread spectrum sequence; and

a second modulator operable to modulate the second spread spectrum sequence onto a second analog signal received from the second signal source, to form a second modulated signal for transmission to the conference bridge via a second communication channel;

a third endpoint comprising;

at least one signal sink; and

a signal and data separator communicably coupled to the at least one signal sink, the signal and data separator comprising;

a demodulator operable to demodulate a signal received from the bridge via a third communication channel, to produce a demodulated signal;

a third CDMA chip sequence generator, operable to generate a third CDMA chip sequence;

a fourth CDMA chip sequence generator, operable to generate a fourth CDMA chip sequence;

a first spreading decoder operable to multiply the demodulated signal by the third CDMA chip sequence, to reconstruct the first digital bit stream; and

a second spreading decoder operable to multiply the demodulated signal by the fourth CDMA chip sequence, to reconstruct the second digital bit stream;

wherein the third CDMA chip sequence is different from the fourth CDMA chip sequence.

21. The system of claim 20, wherein the first CDMA chip sequence is periodically pseudo-randomly selected from one of a plurality of chip sequence generators.

22. The system of claim 21, wherein the plurality of chip sequence generators comprise at least four Gold chip sequence generators.

23. The system of claim 20, wherein the first signal source comprises a microphone.

24. The system of claim 20, wherein the first signal source comprises a video camera.

25. The system of claim 20, wherein the first signal sink comprises a speaker.

26. The system of claim 20, wherein the first signal sink comprises a display device.

27. The system of claim 20, wherein the first communication channel comprises a Plain Old Telephone System channel.

28. The system of claim 20, wherein the first communication channel comprises a radio channel.