REDUNDANT STREAM ALIGNMENT IN IP DATACASTING OVER DVB-H

• US 20080022340A1
• Filed: 06/30/2006
• Published: 01/24/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation
• Inventors: Hannuksela, Miska, Bouazizi, Imed, Jarvinen, Roope
• Granted Patent: US 7,584,495 B2
• Time in Patent Office: Days
• US Class Current: 725/112
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/2362 Generation or processing of Service Information [SI]
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/4425 Monitoring of client processing errors or hardware failure
• CPC Class Codes: H04N 21/631 Multimode Transmission, e.g. transmitting basic layers and enhancement layers of the content over different transmission paths or transmitting with different error corrections, different keys or with different transmission protocols
• CPC Class Codes: H04N 21/64315 DVB-H
• CPC Class Codes: H04N 21/6437 Real-time Transport Protocol [RTP]
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests

Abstract

A real-time program transmission system and method may receive a signal from a content source, and generate two different data streams. One stream may be of a higher quality than the other. The two streams may then be inserted into time slice frames, such that a single frame carries two portions of data: one corresponding to a first time segment in the program, and a second corresponding to a different time segment in the program. A receiving mobile terminal may buffer the received data, and may use the lower quality data as a backup in the event of a transmission error in the higher quality data.

Claims

1. A data transmission method, comprising the steps of:

receiving first and second sequential segments of a program for transmission, wherein said first segment occurs before said second segment in said program;

encoding said first and second segments with a first encoder to form primary encoded data for said segments;

encoding said first and second segments with a second encoder to form redundant encoded data for said segments, said second encoder applying a different encoding process than the first encoder;

transmitting said program using a plurality of periodic bursts of data, wherein a first one of said bursts comprises said primary encoded data for said first segment and said redundant encoded data for said second segment.

2. The method of claim 1, further comprising the step of including, in said first one of said bursts, a delta time value indicating when a subsequent burst will be transmitted.

3. The method of claim 1, wherein said second encoder uses output from said first encoder to form said redundant encoded data for said segments.

4. The method of claim 1, wherein said second redundant encoded data occupies less bandwidth in said burst than said primary encoded data.

5. The method of claim 1, wherein said primary encoded data for said first segment and said redundant encoded data for said second segment are separated in time by additional data within said first burst.

6. The method of claim 1, further comprising the step of transmitting a second burst of data subsequent to said first burst, wherein said second burst comprises said primary encoded data of said second segment, and a redundant encoded data of a third segment occurring after said second segment in said program.

7. The method of claim 1, further comprising the step of applying forward error correction in said step of transmitting.

8. The method of claim 1, further comprising a step of allocating said first and second primary and redundant encoded data to logical streams at an RTP payload layer.

9. The method of claim 1, wherein said burst comprises a DVB-H time slice frame.

10. The method of claim 1, further comprising a step of allocating said first and second primary and redundant encoded data to logical streams at a codec layer.

11. A data receiving method, comprising the steps of:

receiving a first transmission burst, said first burst comprising;

primary encoded data for a first segment of a multimedia program encoded with a first encoder;

redundant encoded data for a second time segment of the multimedia program encoded with a second encoder, and;

a first delta time value for a future transmission burst corresponding to said multimedia program, wherein said second time segment is later in said program than said first time segment.

12. The method of claim 11, further comprising the steps of:

buffering said redundant encoded data for said second time segment;

receiving a second burst, said second burst comprising;

primary encoded data corresponding to the second time segment of said program, and

a second delta time value;

determining whether transmission error occurred with said second burst; and

if an error occurred with said second burst, using said buffered redundant encoded data to provide said second time segment of said program to a user.

13. The method of claim 12, further comprising the steps of:

storing said first delta time value;

activating, at a time according to said first delta time value, reception circuitry prior to said step of receiving said second burst;

deactivating said reception circuitry after said step of receiving said second burst; and

re-activating said reception circuitry for reception at a subsequent time based on said second delta time value.

14. The method of claim 11, wherein said burst comprises a DVB-H time slice frame.

15. The method of claim 11, further comprising a step of assigning said primary and redundant encoding data to a common logical stream.

16. The method of claim 11, wherein said primary and redundant encoding data are separated in time in said burst by additional data.

17. The method of claim 11, wherein a time period of said periodic bursts of data equals a duration of said first time segment of said program.

18. An apparatus, comprising:

reception circuitry configured to receive transmission bursts;

a processor configured to activate said reception circuitry to receive a transmission burst having at least two portions of data, wherein a first portion contains primary encoded data corresponding to a first time segment of a program being received, and a second portion contains redundant encoded data corresponding to a second time segment of said program, said second time segment being later in said program than said first time segment, and wherein said primary and redundant encoded data are encoded differently from one another, and wherein said burst further includes a delta time value for a future burst corresponding to said program;

said processor further configured to deactivate said reception circuitry after said burst is received;

a memory storing said delta time value for a subsequent reception of said future burst corresponding to said program; and

wherein said processor is configured to use previously buffered redundant encoded data for said first time segment to provide said first time segment of said program for the user if said burst is erroneously received.

19. The terminal of claim 18, wherein said primary and redundant data are placed in non-contiguous portions of said burst.