Communication processing apparatus, data communication system, and communication processing method

• US 20060218264A1
• Filed: 03/22/2006
• Published: 09/28/2006
• Est. Priority Date: 03/28/2005
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Igarashi, Tatsuya, Miyama, Seiji, Shitama, Kazuhiro, Ogawa, Akimichi
• Granted Patent: US 7,987,284 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/18 End to end
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 28/22 Negotiating communication rate

Abstract

A communication processing apparatus that acts as a server for transmitting data to a client includes a data transceiver configured to carry out communications with the client; a rate controller configured to control a bitrate of data transmitted to the client; and a data processor configured to prepare data to transmit in accordance with the bitrate. The rate controller includes a throughput calculator configured to extract an effective data transmission and reception period not including an ineffective data transmission and reception period in a period during which a communication connection is maintained between the server and the client, and to calculate a maximum throughput on the basis of the length of the effective data transmission and reception period and the amount of data transmitted; and a bitrate setter configured to set a bitrate within a range of up to a maximum allowable bitrate corresponding to the maximum throughput calculated by the throughput calculator.

Claims

1. A communication processing apparatus that acts as a server for transmitting data to a client, the communication processing apparatus comprising:

a data transceiver configured to carry out communications with the client;

a rate controller configured to control and determine a bitrate of data transmitted to the client; and

a data processor configured to prepare data to transmit in accordance with the bitrate determined by the rate controller;

wherein the rate controller includes

a throughput calculator configured to extract an effective data transmission and reception period not including an ineffective data transmission and reception period, the effective and ineffective data transmission and reception periods occurring in a period during which a communication connection is maintained between the server and the client, and to calculate a maximum throughput on the basis of the length of the effective data transmission and reception period and the amount of data transmitted; and

a bitrate setter configured to set a transmission bitrate within a range of up to a maximum allowable bitrate corresponding to the maximum throughput calculated by the throughput calculator.

2. The communication processing apparatus according to claim 1, wherein the throughput calculator is configured to define an effective data transmission and reception period corresponding to a period from a start of successive data transmission based on a window size to reception of a reception acknowledgement for the successively transmitted data, and to calculate a maximum throughput on the basis of the length of the effective data transmission and reception period and the amount of data transmitted.

3. The communication processing apparatus according to claim 1, wherein the throughput calculator is configured to define an effective data transmission and reception period corresponding to a period from a start of successive data transmission based on a window size to reception of a reception acknowledgement for the successively transmitted data, to obtain a plurality of pieces of sample data associated with a plurality of effective data transmission and reception periods, and to calculate a maximum throughput on the basis of a plurality of pieces of sample data excluding pieces of data determined as having exceptional values among the plurality of pieces of sample data obtained.

4. The communication processing apparatus according to claim 1, wherein the bitrate setter is configured to set a bitrate on the basis of transition of an estimated buffer amount of a client buffer, and to increase the bitrate within a range of up to an upper limit of the maximum allowable bitrate corresponding to the maximum throughput calculated by the throughput calculator when the estimated buffer amount is greater than or equal to a predetermined threshold.

5. The communication processing apparatus according to claim 4, wherein the bitrate setter is configured to estimate the amount of the client buffer through calculation according to an equation expressed as the estimated buffer amount of the client buffer=B_cli+D_serv−

R*T, using the following information (a) to (d);

(a) a buffer amount B_cli, expressed in bytes, reported from the client at the time of a start of communication;

(b) a time T, expressed in seconds, elapsed since a start of playback by the client;

(c) an amount D_serv, expressed in bytes, of data transmitted from the server during the elapsed time T since the start of playback by the client; and

(d) a playback rate R, expressed in bytes per second, of content that is obtainable from content transmitted.

6. The communication processing apparatus according to claim 1,

wherein the data transceiver is configured to receive communication-bandwidth information from an access point that acts as an intermediary for communications with the client, the communication-bandwidth information relating to a communication bandwidth between the access point and the client, and

wherein the bitrate setter is configured to set a transmission bitrate on the basis of the communication-bandwidth information.

7. The communication processing apparatus according to claim 6, wherein the communication-bandwidth information includes information that is generated on the basis of data relating to at least one of a round trip time, a received signal strength indicator, and a transmission rate of communications between the access point and the client.

8. A communication processing apparatus that acts as a server for transmitting data to a client, the communication processing apparatus comprising:

a data transceiver configured to carry out communications with the client;

a rate controller configured to control and determine a bitrate of data transmitted to the client; and

a data processor configured to prepare data to transmit in accordance with the bitrate determined by the rate controller;

wherein the rate controller includes a bitrate setter configured to define a maximum throughput calculated on the basis of reception-interval information of data packets that are transmitted successively in a period during which a communication connection is maintained between the server and the client, and to set a transmission bitrate within a range of up to a maximum allowable bitrate corresponding to the maximum throughput.

9. The communication processing apparatus according to claim 8,

wherein the rate controller includes a throughput calculator configured to receive from the client reception-interval information of data packets that are transmitted successively in a period during which a communication connection is maintained between the server and the client, and to calculate a maximum throughput on the basis of the reception-interval information and the amount of data transmitted, and

wherein the bitrate setter is configured to set a transmission bitrate within a range of up to a maximum allowable bitrate corresponding to the maximum throughput calculated by the throughput calculator.

10. The communication processing apparatus according to claim 8, wherein the data transceiver is configured to successively transmit packets having packet headers with urgent flags set to a specific value, the urgent flags set to the specific value serving as identification information of packets with which the client is supposed to measure a reception interval.

11. The communication processing apparatus according to claim 8, wherein the bitrate setter is configured to set a bitrate on the basis of transition of an estimated buffer amount of a client buffer, and to increase the bitrate within a range of up to an upper limit of the maximum allowable bitrate corresponding to the maximum throughput calculated by the throughput calculator when the estimated buffer amount is greater than or equal to a predetermined threshold.

12. The communication processing apparatus according to claim 11, wherein the bitrate setter is configured to estimate the amount of the client buffer through calculation according to an equation expressed as the estimated buffer amount of the client buffer=B_cli+D_serv−

R*T, using the following information (a) to (d);

(a) a buffer amount B_cli, expressed in bytes, reported from the client at the time of a start of communication;

(b) a time T, expressed in seconds, elapsed since a start of playback by the client;

(c) an amount D_serv, expressed in bytes, of data transmitted from the server during the elapsed time T since the start of playback by the client; and

(d) a playback rate R, expressed in bytes per second, of content that is obtainable from content transmitted.

13. The communication processing apparatus according to claim 8,

wherein the data transceiver is configured to receive communication-bandwidth information from an access point that acts as an intermediary for communications with the client, the communication-bandwidth information relating to a communication bandwidth between the access point and the client, and

wherein the bitrate setter is configured to set a transmission bitrate on the basis of the communication-bandwidth information.

14. The communication processing apparatus according to claim 13, wherein the communication-bandwidth information includes information that is generated on the basis of data relating to at least one of a round trip time, a received signal strength indicator, and a transmission rate of communications between the access point and the client.

15. A communication processing apparatus that acts as a client for receiving data from a server, the communication processing apparatus comprising:

a data transceiver configured to carry out communications with the server; and

a packet-interval measurer configured to measure a reception interval of data packets received from the server;

wherein the packet-interval measurer is configured to measure a reception interval of packets that are received successively, according to identification information included in packets received from the server, and to transmit reception-interval information representing the reception interval or throughput information calculated on the basis of the reception interval to the server via the data transceiver.

16. The communication processing apparatus according to claim 15, wherein the packet-interval measurer is configured to measure a reception interval of successively received packets according to setting of urgent flags of packet headers included in the packets received from the server.

17. A data communication system comprising a server and a client that transmit and receive data,

wherein the client is configured to measure a reception interval of packets that are received successively, according to identification information included in packets received from the server, and to transmit reception-interval information representing the reception interval or throughput information calculated on the basis of the reception interval to the server, and

wherein the server is configured to set a transmission bitrate within a range of up to a maximum allowable bitrate corresponding to a maximum throughput that is calculated on the basis of the throughput information or the reception-interval information received from the client, and to transmit data to the client according to the transmission bitrate.

18. The data communication system according to claim 17, wherein the server is configured to receive communication-bandwidth information from an access point that acts as an intermediary for communications with the client, the communication-bandwidth information relating to a communication bandwidth between the access point and the client, and to determine a transmission bitrate on the basis of the communication-bandwidth information.

19. A communication processing method of a server that transmits data, the communication processing method comprising the steps of:

controlling and determining a bitrate of data transmitted to a client; and

preparing data to transmit in accordance with the bitrate determined in the rate controlling step;

wherein the rate controlling step includes the steps of

extracting an effective data transmission and reception period not including an ineffective data transmission and reception period, the effective and ineffective data transmission and reception periods occurring in a period during which a communication connection is maintained between the server and the client, and calculating a maximum throughput on the basis of the length of the effective data transmission and reception period and the amount of data transmitted; and

setting a transmission bitrate within a range of up to a maximum allowable bitrate corresponding to the maximum throughput calculated in the throughput calculating step.

20. The communication processing method according to claim 19, wherein the throughput calculating step defines an effective data transmission and reception period corresponding to a period from a start of successive data transmission based on a window size to reception of a reception acknowledgement for the successively transmitted data, and calculates a maximum throughput on the basis of the length of the effective data transmission and reception period and the amount of data transmitted.

21. The communication processing method according to claim 19, wherein the throughput calculating step defines an effective data transmission and reception period corresponding to a period from a start of successive data transmission based on a window size to reception of a reception acknowledgement for the successively transmitted data, obtains a plurality of pieces of sample data associated with a plurality of effective data transmission and reception periods, and calculates a maximum throughput on the basis of a plurality of pieces of sample data excluding pieces of data determined as having exceptional values among the plurality of pieces of sample data obtained.

22. The communication processing method according to claim 19, wherein the bitrate setting step sets a bitrate on the basis of transition of an estimated buffer amount of a client buffer, and increases the bitrate within a range of up to an upper limit of the maximum allowable bitrate corresponding to the maximum throughput calculated in the throughput calculating step when the estimated buffer amount is greater than or equal to a predetermined threshold.

23. The communication processing method according to claim 22, wherein the bitrate setting step estimates the amount of the client buffer through calculation according to an equation expressed as the estimated buffer amount of the client buffer=B_cli+D_serv−

R*T, using the following information (a) to (d);

(a) a buffer amount B_cli, expressed in bytes, reported from the client at the time of a start of communication;

(b) a time T, expressed in seconds, elapsed since a start of playback by the client;

(c) an amount D_serv, expressed in bytes, of data transmitted from the server during the elapsed time T since the start of playback by the client; and

(d) a playback rate R, expressed in bytes per second, of content that is obtainable from content transmitted.

24. The communication processing method according to claim 19, further comprising the step of receiving communication-bandwidth information from an access point that acts as an intermediary for communications with the client, the communication-bandwidth information relating to a communication bandwidth between the access point and the client,

wherein the bitrate setting step sets a transmission bitrate on the basis of the communication-bandwidth information.

25. The communication processing method according to claim 24, wherein the communication-bandwidth information includes information that is generated on the basis of data relating to at least one of a round trip time, a received signal strength indicator, and a transmission rate of communications between the access point and the client.

26. A communication processing method of a server that transmits data, the communication processing method comprising the steps of:

controlling and determining a bitrate of data transmitted to a client; and

preparing data to transmit in accordance with the bitrate determined in the rate controlling step;

wherein the rate controlling step includes the steps of

defining a maximum throughput calculated on the basis of reception-interval information of data packets that are transmitted successively in a period during which a communication connection is maintained between the server and the client, and setting a transmission bitrate within a range of up to a maximum allowable bitrate corresponding to the maximum throughput.

27. The communication processing method according to claim 26,

wherein the rate controlling step includes the step of receiving from the client reception-interval information of data packets that are transmitted successively in a period during which a communication connection is maintained between the server and the client, and calculating a maximum throughput on the basis of the reception-interval information and the amount of data transmitted, and

wherein the bitrate setting step sets a transmission bitrate within a range of up to a maximum allowable bitrate corresponding to the maximum throughput calculated in the throughput calculating step.

28. The communication processing method according to claim 26, further comprising the step of successively transmitting packets having packet headers with urgent flags set to a specific value, the urgent flags set to the specific value serving as identification information of packets with which the client is supposed to measure a reception interval.

29. The communication processing method according to claim 26, wherein the bitrate setting step sets a bitrate on the basis of transition of an estimated buffer amount of a client buffer, and increases the bitrate within a range of up to an upper limit of the maximum allowable bitrate corresponding to the maximum throughput calculated in the throughput calculating step when the estimated buffer amount is greater than or equal to a predetermined threshold.

30. The communication processing method according to claim 29, wherein the bitrate setting step estimates the amount of the client buffer through calculation according to an equation expressed as the estimated buffer amount of the client buffer=B_cli+D_serv−

R*T, using the following information (a) to (d);

(a) a buffer amount B_cli, expressed in bytes, reported from the client at the time of a start of communication;

(b) a time T, expressed in seconds, elapsed since a start of playback by the client;

(c) an amount D_serv, expressed in bytes, of data transmitted from the server during the elapsed time T since the start of playback by the client; and

(d) a playback rate R, expressed in bytes per second, of content that is obtainable from content transmitted.

31. The communication processing method according to claim 26, further comprising the step of receiving communication-bandwidth information from an access point that acts as an intermediary for communications with the client, the communication-bandwidth information relating to a communication bandwidth between the access point and the client,

wherein the bitrate setting step sets a transmission bitrate on the basis of the communication-bandwidth information.

32. The communication processing method according to claim 31, wherein the communication-bandwidth information includes information that is generated on the basis of data relating to at least one of a round trip time, a received signal strength indicator, and a transmission rate of communications between the access point and the client.

33. A communication processing method of a client that receives data, the communication processing method comprising the steps of:

measuring a reception interval of packets that are received successively, according to identification information included in packets received from a server; and

transmitting packet-reception-interval information representing the packet reception interval measured in the packet-reception-interval measuring step or throughput information calculated on the basis of the reception interval to the server.

34. The communication processing method according to claim 33, wherein the packet-reception-interval measuring step measures a reception interval of successively received packets according to setting of urgent flags of packet headers included in the packets received from the server.