Method and system for spatially disjoint joint source and channel coding for high-quality real-time multimedia streaming over connection-less networks via circuit-switched interface links

• US 6,574,218 B1
• Filed: 05/25/1999
• Issued: 06/03/2003
• Est. Priority Date: 05/25/1999
• Status: Expired due to Term

• Current Assignee: Open Invention Network LLC
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Cooklev, Todor
• Primary Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US09/318,182
• Time in Patent Office: 1,470 Days
• Field of Search: 370/352, 370/353, 370/356, 370/389, 370/468, 370/401, 709/247, 709/246, 709/229, 714/2, 714/776, 714/758
• US Class Current: 370/352
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/104 in the network
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04M 2207/203 composed of PSTN and data network, e.g. the Internet

Abstract

A system and method for providing multimedia data streaming over a mixed network including a packet-switched and circuit-switched network. The multimedia source server performs both source coding to reduce the overall size of the data and channel coding to provide redundancy for packet reconstruction of lost or late packets. The source coding (or compression) and channel coding (protection against packet loss) are designed jointly, but are performed at two different locations to achieve optimum utilization of bandwidth. The channel coding is removed and packet reconstruction or concealment is performed at the edge of the packet-based network prior to passing the multimedia data on to the circuit-switched network. Retransmission is unnecessary in the present invention which is undesirable for real-time data streaming. A bidirectional embodiment is also described.

Claims

1. A system for transferring a real-time multimedia data stream over a packet-switched network and through a circuit-switched network to a user, the system comprising:

a server having the real-time multimedia data stream available thereto, the server to source code the real-time multimedia data stream into source coded multimedia data and to channel code at least a portion of the source coded multimedia data into source and channel coded multimedia data wherein the server comprises a channel coder to code redundant information describing the at least a portion of the source coded multimedia data into the source and channel coded multimedia data, wherein the channel coder comprises a dither process to add dither to the redundant information during channel coding of the source coded multimedia data;

a remote access gateway operably coupled to the server via the packet-switched network, the remote access gateway to channel decode the source and channel coded multimedia data into reconstructed source coded multimedia data; and

a client operably coupled to the remote access gateway via the circuit-switched network to source decode the reconstructed source coded multimedia data into a reconstructed real-time multimedia data stream for perceiving by the user.

2. The system, as recited in claim 1, wherein the server further comprises a packetizer to partition the source coded multimedia data into packets prior to transmitting the source and coded multimedia data into the packet-switched network.

3. The system, as recited in claim 1, wherein the server further comprises a quality of service manager to monitor in conjunction with the remote access gateway the amount of the redundant information required to accommodate channel losses of portions of the source and channel coded multimedia data.

4. The system, as recited in claim 1, wherein the remote access gateway further comprises a packet processor to receive the source and channel coded multimedia data from the server and to channel decode the source and channel coded multimedia data into reconstructed source coded multimedia data.

5. The system, as recited in claim 4, wherein the remote access gateway further comprises:

a missing packet reconstructor process which, upon detection by the packet processor of a missing portion of the source and channel coded multimedia data and when determined to be important, the missing packet reconstructor process reconstructing the missing portion of the source and channel coded multimedia data from redundant information of other portions of the source and channel coded multimedia data; and

an error concealment process which, upon detection by the packet processor of the missing portion of the source and channel coded multimedia data and when the missing portion of the source and channel coded multimedia data is determined by the packet processor to be unimportant or when the importance is undeterminable, the error concealment process creating a substitute portion for replacing the missing portion of the source and channel coded multimedia data.

6. The system, as recited in claim 4, wherein the remote access gateway further comprises a quality of service manager to monitor the packet processor in determining the amount of redundant information required in the server performing channel coding to accommodate reconstruction of the portions of the source and channel coded multimedia data lost when delivered through the packet-switched network to the remote access gateway.

7. The system, as recited in claim 4, wherein when the server employs subtractive dither to channel code the source coded multimedia data the remote access gateway further comprises a dither process to subtract dither from the redundant information during channel decoding of the source and channel coded multimedia data.

8. In a real-time multimedia data streaming system, a method for operably coupling between a packet-switched network and a circuit-switched network for transferring a real-time multimedia data stream, that has been source and channel coded into source and channel coded multimedia data, between the packet-switched network and the circuit-switched network, the method comprising:

receiving the source and channel coded multimedia data from the packet-switched network;

evaluating portions of the source and channel coded multimedia data;

detecting a missing portion of the source and channel coded multimedia data;

determining the importance of the missing portion of the source and channel coded multimedia data;

reconstructing the missing portion of the source and channel coded multimedia data from other portions of the source and channel coded multimedia data when the missing portion of the source and channel coded multimedia data is found to be important from the step of determining; and

creating a substitute portion for replacing the missing portion of the source and channel coded multimedia data when the missing portion of the source and channel coded multimedia data is determined to be unimportant from the step of determining.

9. The method, as recited in claim 8, further comprising monitoring to determine the amount of redundant information required to accommodate reconstruction of the missing portions of the source and channel coded multimedia data lost when delivered through the packet-switched network.

10. In a real-time multimedia data streaming system, a remote access gateway for operably coupling between a packet-switched network and a circuit-switched network for transferring a real-time multimedia data stream, that has been source and channel coded into source and channel coded multimedia data, between the packet-switched network and the circuit-switched network, the remote access gateway comprising:

a packet processor to receive the source and channel coded multimedia data from the packet-switched network and to evaluate portions of the source and channel coded multimedia data;

a missing packet reconstructor process which, upon detection by the packet processor of a missing portion of the source and channel coded multimedia data and determination of the importance of the missing portion of the source and channel coded multimedia data, and when important, the missing packet reconstructor process for reconstructing the missing portion of the source and channel coded multimedia data from other portions of the source and channel coded multimedia data;

an error concealment process which, upon detection by the packet processor of the missing portion of the source and channel coded multimedia data and when the missing portion of the source and channel coded multimedia data is determined by the packet processor to be unimportant or when the importance is undeterminable, the error concealment process for creating a substitute portion for replacing the missing portion of the source and channel coded multimedia data; and

when the source and channel coded multimedia data employs subtractive dither to channel code, a dither process to subtract dither from the redundant information during channel decoding of the source and channel coded multimedia data.

11. In a real-time multimedia data streaming system, a server operably coupled to a packet-switched network wherein the packet-switched network is further operably coupled to a circuit-switched network, the server for transferring a real-time multimedia data stream from the server to a client via a remote access gateway, the server comprising:

a source coder to source code the real-time multimedia data stream into source coded multimedia data; and

a channel coder to channel code at least a portion of the source coded multimedia data into source and channel coded multimedia data, the channel coder for determining an importance of each portion of the source coded multimedia data and for each important one of the source coded multimedia data coding redundant information describing the important one of the source coded multimedia data into the source and channel coded multimedia data.

12. The server, as recited in claim 11, wherein the server further comprises a packetizer to partition the source coded multimedia data into packets prior to transmitting the source and channel coded multimedia data into the packet-switched network.

13. The server, as recited in claim 11, wherein the server further comprises a quality of service manager to monitor in conjunction with the remote access gateway the amount of the redundant information required to accommodate channel losses of portions of the source and channel coded multimedia data.

14. In a real-time multimedia data streaming system, a server operably coupled to a packet-switched network wherein the packet-switched network is further operably coupled to a circuit-switched network, the server for transferring a real-time multimedia data stream from the server to a client via a remote access gateway, the server comprising:

a source coder to source code the real-time multimedia data stream into source coded multimedia data; and

a channel coder to channel code at least a portion of the source coded multimedia data into source and channel coded multimedia data, the channel coder for determining an importance of each portion of the source coded multimedia data and for each important one of the source coded multimedia data coding redundant information describing the important one of the source coded multimedia data into the source and channel coded multimedia data wherein the channel coder further comprises a dither process to add dither to the redundant information during channel coding of the source coded multimedia data.

15. A method for real-time multimedia data streaming from a server over a packet-switched network to a remote access gateway and through a circuit-switched link to a client, the method comprising the steps of:

source coding at the server a real-time multimedia data stream into source coded multimedia data;

channel coding at least a portion of the source coded multimedia data into source and channel coded multimedia data comprising coding redundant information describing the at least a portion of the source coded multimedia data into the source and channel coded multimedia data wherein coding further comprises adding dither to the redundant information during channel coding of the source coded multimedia data;

channel decoding at the remote access gateway the source and channel coded multimedia data into reconstructed source coded multimedia data; and

source decoding at the client the reconstructed source coded multimedia data into a reconstructed real-time multimedia data stream for presentation by the client.

16. The method, as recited in claim 15, further comprising the step of packetizing the source coded multimedia data into packets prior to transmitting the source and coded multimedia data into the packet-switched network.

17. The method, as recited in claim 15, further comprising the steps of:

receiving the source and channel coded multimedia data from the packet-switched network;

evaluating portions of the source and channel coded multimedia data;

upon detection of a missing portion of the source and channel coded multimedia data, determining the importance of the missing portion of the source and channel coded multimedia data, and when important, attempting to reconstruct the missing portion of the source and channel coded multimedia data from other portions of the source and channel coded multimedia data; and

upon detection of the missing portion of the source and channel coded multimedia data and when the missing portion of the source and channel coded multimedia data is determined to be unimportant or when the importance is undeterminable, creating a substitute portion for replacing the missing portion of the source and channel coded multimedia data.