High capacity robust modem for multiple classes of services

• US 6,801,495 B1
• Filed: 02/28/2000
• Issued: 10/05/2004
• Est. Priority Date: 02/28/2000
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Homayoun, Fereidoun, Faruque, Saleh
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): DUONG, DUC T
• Application Number:
  US09/514,932
• Time in Patent Office: 1,681 Days
• Field of Search: 370/208, 370/209, 370/268, 370/335, 370/342, 370/441, 370/479, 370/493, 370/494, 370/495, 370/206, 375/134, 375/137, 375/222
• US Class Current: 370/208
• CPC Class Codes: H04J 13/004 Orthogonal
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes

Abstract

A low-cost data communication system and method using modems to provide high speed multi-class services to subscribers is disclosed. In the present invention, an n-bit orthogonal modulating code is uniquely partitioned into several subsets whereas each subset is assigned to a particular class of services. When data streams from different classes of services go through an encoding modem equipped with the partitioned orthogonal codes, they can be split based on their classes, encoded, modulated through a multilevel phase modulation simultaneously. Thereafter, since the encoded streams are orthogonal to each other, they can be combined as a composite modulated outgoing data stream and transmitted through a wired communication channel such as a cable or optical fiber channel. At a receiving end, a decoding modem can receive the encoding scheme from the encoding modem, and appropriately decode the transmitted information. This method enables sharing the same communication channel by multiple classes of services and processing different classes of information separately but simultaneously, and thus enhancing the overall performance of the shared communication channel.

Claims

1. A method for providing one or more classes of communication services for one or more users through a shared wired communication channel, the users being connected to the communication channel via a multiple access node, the method comprising the steps of:

orthogonally encoding an incoming information stream sent by each user by an encoding modem using a multi-class encoding process;

wherein the step of orthogonally encoding further includes the steps of splitting the incoming information stream into one or more classes, each class representing a first level sub stream of information;

dividing each first level sub stream into a plurality of second level sub streams of information;

encoding the second level sub streams with a predetermined set of orthogonal codes according to a predetermined code plan;

modulating each encoded sub stream by a modulating signal; and

combining the modulated sub streams into one fully encoded data stream; and

transmitting the encoded information through the multiple access node to the shared wired communication channel;

wherein the multi-class encoding process is implemented according to the predetermined code plan designating specific orthogonal codes for each class of communication service.

2. The method of claim 1 wherein the step of encoding uses at least one Read Only Memory for processing the second level sub streams of information.

3. The method of claim 1 wherein the predetermined code plan partitions a selected n-bit orthogonal code into one or more subsets of orthogonal codes, wherein each subset is used for encoding a class of information.

4. The method of claim 3 wherein a code sense multiple access protocol is implemented so that the users can instantly monitor an available orthogonal code.

5. The method of claim 1 wherein the classes of information are audio information, video information, and data information.

6. The method of claim 1 further includes the steps of:

demodulating the encoded data; and

extracting the encoded data based on a predetermined encoding scheme providing the encoding modem,

wherein the steps of demodulating and extracting are performed in a decoding modem.

7. The method of claim 1 wherein the multiple access node includes a multichannel transceiver, a combiner, a splitter, and a duplexer.

8. A method for efficient information communication between a transmitting end and a receiving end through a wired communication channel shared by one or more users connected to the transmitting end, the information including one or more classes of information, the method comprising the steps of:

splitting an incoming information stream at the transmitting end into one or more classes of information, each class being a first level sub stream of information, the classes including audio information, video information, and data information;

dividing each first level sub stream of information into a plurality of second level sub streams of information;

orthogonally encoding each of the second level sub streams of information by an available orthogonal code according to a predetermined code plan; and

transmitting the encoded streams of information as one outgoing information stream from the transmitting end to the receiving end via the wired communication channel; and

decoding the encoded streams at the receiving end,

wherein the predetermined code plan designates orthogonal codes servicing each class of information for preventing interferences and providing efficient use of the communication channel.

9. The method of claim 8 further includes the steps of:

modulating each second level sub stream by a modulating signal; and

combining the modulated sub streams into one outgoing encoded information stream.

10. The method of claim 8 wherein the step of orthogonally encoding uses at least one Read Only Memory for processing the second level sub streams of information.

11. The method of claim 8 wherein the predetermined code plan partitions a selected n-bit orthogonal code into one or more subsets of orthogonal codes, wherein each subset is used for encoding a class of information.

12. The method of claim 8 wherein the transmitting end connects to the communication channel via a multiple access node.

13. The method of claim 8 wherein each user connected to the transmitting end implements a code sense multiple access protocol for monitoring an available orthogonal code for encoding purpose.

14. The method of claim 8 wherein the step of decoding further includes the steps of:

demodulating the encoded data; and

extracting the encoded data based on a predetermined encoding scheme provided by the encoding modem.

15. A system for providing one or more classes of communication services for one or more users through a shared wired communication channel, the users being connected to the communication channel via a multiple access node, the system comprising:

means for orthogonally encoding an incoming information stream sent by each user by an encoding modem using a multi-class encoding process;

means for splitting the incoming information stream into one or more classes, each class representing a first level sub stream of information;

means for dividing each first level sub stream into a plurality of second level sub streams of information;

means for encoding the second level sub streams with a predetermined set of orthogonal codes according to a predetermined code plan;

a modulator for modulating each encoded sub stream by a modulating signal;

means for combining the modulated sub streams into one fully encoded outgoing information stream; and

means for transmitting the encoded information through the multiple access node to the shared wired communication channel, wherein the multi-class encoding process is implemented according to the predetermined code plan designating specific orthogonal codes for each class of communication service.

16. The system of claim 15 wherein the means for encoding uses at least one Read Only Memory for processing the second level sub streams of information.

17. The system of claim 15 wherein the predetermined code plan partitions a selected n-bit orthogonal code into one or more subsets of orthogonal codes, wherein each subset is used for encoding a class of information.

18. The system of claim 17 wherein a code sense multiple access protocol is implemented whereby the users can instantly monitor available orthogonal codes.

19. The system of claim 15 wherein the classes of information are audio information, video information, and data information.

20. The system of claim 15 further includes the means for:

demodulating the encoded data; and

extracting the encoded data based on a predetermined encoding scheme provided by the encoding modem,

wherein the means for demodulating and extracting are done in a decoding modem.

21. The system of claim 15 wherein the multiple access node includes a multichannel transceiver, a combiner, a splitter and a duplexer.