METHOD OF PREDICTING THE TRANSMISSION ERROR RATE IN A COMMUNICATION NETWORK AND SERVER IMPLEMENTING SUCH A METHOD

• US 20100061251A1
• Filed: 09/08/2009
• Published: 03/11/2010
• Est. Priority Date: 09/08/2008
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Maze, Frédéric, Le Floch, Hervé, Nassor, Eric
• Granted Patent: US 8,094,578 B2
• Time in Patent Office: Days
• US Class Current: 370/242
• CPC Class Codes: H03M 13/353 Adaptation to the channel
• CPC Class Codes: H03M 13/6547 TCP, UDP, IP and associated protocols, e.g. RTP
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/127 by using congestion prediction
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/38 by adapting coding or compression rate
• CPC Class Codes: H04N 21/236 Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream multiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/2404 Monitoring of server processing errors or hardware failure error or fault detection G06F11/07; monitoring in general G06F11/30
• CPC Class Codes: H04N 21/2408 Monitoring of the upstream path of the transmission network, e.g. client requests monitoring data switching networks utilization H04L43/0876; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/434 Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream demultiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/643 Communication protocols network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP], H04L65/65
• CPC Class Codes: H04N 7/173 with two-way working, e.g. subscriber sending a programme selection signal

Abstract

To predict the transmission error rate in a stream of data packets transmitted between a server and at least one client in a communication network: the server sends at least one group of packets to the client; the client calculates a plurality of items of statistical information on the group of packets and transmits them to the server; the server analyzes the items of statistical information so as to obtain a network stability indicator; and the server calculates a prediction of the transmission error rate on the basis of the network stability indicator.

Claims

1. A method of predicting the transmission error rate in a stream of data packets transmitted between a server and at least one client in a communication network, wherein said method comprises the steps of:

sending by the server to the client at least one group of packets;

calculating by the client a plurality of items of statistical information on the group of packets and transmitting by the client said items of statistical information to the server;

analyzing by the server said statistical information so as to obtain a network stability indicator; and

calculating by the server a prediction of said transmission error rate on the basis of said network stability indicator.

2. A method according to claim 1, wherein, at the step of analyzing the statistical information, the server determines the position of the errors in the group of packets.

3. A method according to claim 2, wherein if the server determines that a majority of errors is situated at the end of groups, the network stability indictor indicates that the network is of stable type.

4. A method according to claim 2, wherein if the server determines that a majority of errors is situated at the beginning of groups, the network

stability indictor indicates that the network is of unstable type.

5. A method according to claim 1, wherein the client calculates the capacity of the network for each packet of the group of packets, defined by B_i=S_i/d_i, where S_i is the size of the packet and d_i is the variation, between two consecutive packets, of the transmission duration of a packet.

6. A method according to claim 5, wherein, at the step of analyzing the statistical information, the server analyzes the variations in measurement of the capacity of the network and deduces therefrom the network stability indicator.

7. A method according to claim 5, wherein, at the step of analyzing the statistical information, the server compares the capacity of the network with the rate of the stream over the network and deduces therefrom the network stability indicator.

8. A method according to claim 1, wherein, if the network stability indicator indicates that the network is of unstable type, the server calculates a prediction of the error rate on the basis of long term statistics on the number of errors in the past.

9. A method according to claim 1, wherein, if the network stability indicator indicates that the network is of stable type with a share of the rate used by the stream of data packets greater than a first predetermined threshold, the server calculates a prediction of the error rate on the basis of statistics on the position of the errors in the group of packets, and if the network stability indicator indicates that the network is of stable type with a share of the rate used by the stream of data packets less than a second predetermined threshold, the server calculates a prediction of the error rate on the basis of short term statistics on the evolution of the transmission duration of the packets.

10. A method according to claim 1, wherein it further comprises a step of determining by the server the reliability of the prediction of the transmission error rate on the basis of said network stability indicator.

11. A method according to claim 10, wherein the server selects a predictive error correction method on the basis of the prediction of the transmission error rate and of the reliability of said prediction.

12. A method according to claim 11, wherein the server chooses a predetermined redundancy rate for an error correction method on the basis of the prediction of the transmission error rate and of the reliability of the prediction.

13. A method according to claim 11, in which the data are video data, wherein the server chooses an intra coding mode for the data depending on the prediction of the transmission error rate and on the reliability of the prediction.

24. An information storage means which can be read by a computer or a microprocessor storing instructions of a computer program, wherein it makes it possible to implement a predicting method according to claim 1.

25. A computer program product which can be loaded into a programmable apparatus, wherein it comprises sequences of instructions for implementing a predicting method according to claim 1, when that program is loaded and executed by the programmable apparatus.

14. A server for transmitting a stream of data packets, in a communication network comprising at least one client, wherein said server comprises:

means for sending at least one group of packets to the client;

means for receiving a plurality of items of statistical information on the group of packets;

means for analyzing said statistical information so as to obtain a network stability indicator; and

means for calculating a prediction of the transmission error rate on the basis of said network stability indicator.

15. A server according to claim 14, wherein it further comprises means for determining the position of the errors in the group of packets.

16. A server according to claim 14, wherein it further comprises means for analyzing the variations in measurement of the capacity of the network and for deducing therefrom the network stability indicator, the capacity of the network being defined, for each packet of the group of packets, by B_i=S_i/d_i, where S_i is the size of the packet and d_i is the variation, between two consecutive packets, of the transmission duration of a packet.

17. A server according to claim 14, wherein it further comprises means for comparing the capacity of the network with the rate of the stream over the network and for deducing therefrom the network stability indicator, the capacity of the network being defined, for each packet of the group of packets, by B_i=S_i/d_i, where S_i is the size of the packet and d_i is the variation, between two consecutive packets, of the transmission duration of a packet.

18. A server according to claim 14, wherein said calculating means are adapted to calculate a prediction of the transmission error rate on the basis of long term statistics on the number of errors in the past, if the network stability indicator indicates that the network is of unstable type.

19. A server according to any one of claim 14, wherein said calculating means are adapted to calculate a prediction of the transmission error rate on the basis of statistics on the position of the errors in the group of packets, if the network stability indicator indicates that the network is of stable type with a share of the rate used by the stream of data packets greater than a first predetermined threshold, and are adapted to calculate a prediction of the transmission error rate on the basis of short term statistics on the evolution of the transmission duration of the packets, if the network stability indicator indicates that the network is of stable type with a share of the rate used by the stream of data packets less than a second predetermined threshold.

20. A server according to claim 14, wherein it further comprises means for determining the reliability of the prediction of the transmission error rate on the basis of said network stability indicator.

21. A server according to claim 20, wherein it further comprises means for selecting a predictive error correction method on the basis of the prediction of the transmission error rate and of the reliability of said prediction.

22. A server according to claim 21, wherein it further comprises means for choosing a predetermined redundancy rate for an error correction method on the basis of the prediction of the transmission error rate and of the reliability of the prediction.

23. A server according to claim 21, in which the data are video data, wherein it further comprises means for choosing an intra coding mode for the data on the basis of the prediction of the transmission error rate and of the reliability of said prediction.