Data transmission in non-reliable networks

• US 20010025239A1
• Filed: 03/02/2001
• Published: 09/27/2001
• Est. Priority Date: 03/02/2000
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hakenberg, Rolf, Burmeister, Carsten, Wiebke, Thomas
• Granted Patent: US 7,051,358 B2
• Time in Patent Office: Days
• US Class Current: 704/200.1
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 47/38 by adapting coding or compression rate
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/166 concerning the amount of transmission errors, e.g. bit error rate [BER]
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 21/6377 directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 21/658 Transmission by the client directed to the server
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

The present invention relates to a method and apparatus for transmitting video and/or audio data in a non-reliable and bandlimited network from a server to a client. The network may for instance be a wireless network. The data stream includes P-frames and I-frames. If during transmission a frame gets lost, the client notifies the server of the data loss when the next packet is received at the client correctly. The server then skips all the P-frames of the current P-frame sequence and continues the transmission with the next I-frame. Preferably, each packet has assigned a sequence number and the message from the client includes the sequence number of the currently received packet. The server may ignore a message from the client if the client'"'"'s request for skipping the P-frames has already been executed. It is preferred to make use of the present invention for streaming MPEG data.

Claims

1. Method for transmitting video and/or audio data in a non-reliable network from a server (110) to a client (160), said data being arranged in data frames forming a data stream, said data frames including P-frames and I-frames, the method comprising the steps of:

receiving (S530) at the server a message (NACK) indicating that a data frame is missing, said message being sent from the client over the non-reliable network; and

continuing (S550-S570) the transmission of the data stream with the next I-frame, thereby skipping the P-frames up to said I-frame.

2. The method according to

claim 1

, further comprising the steps of assigning a sequence number (SN) to each data frame.

3. The method according to

claim 2

, wherein said message from the client contains the sequence number of the last data frame which has been properly received at the client.

4. The method according to one of

claims 1

to

3

, further comprising the step of ignoring (S540) said message from the client if the server has already received a corresponding previous message from the client relating to the same data frame loss.

5. The method according to one of

claims 1

to

4

, wherein the data frames are MPEG frames.

6. The method according to one of

claims 1

to

5

, wherein said non-reliable network is a wireless network.

8. The apparatus according to

claim 7

, being arranged for performing the method according to one of

claims 1

to

6

.

7. Apparatus for transmitting video and/audio data in a non-reliable network to a remote client (160), said data being arranged in data frames forming a data stream, said data frames including P-frames and I-frames, the apparatus comprising:

means (230) for receiving (S530) from the client a message (NACK) indicating that a data frame is missing, said message being sent from the client over the non-reliable network; and

a controller (210) for continuing (S550-S570) the transmission of the data stream with the next I-frame, thereby skipping the P-frames up to said I-frame.