Communication system, communication method, communication apparatus, communication control method, and computer program

• US 20040264425A1
• Filed: 05/03/2004
• Published: 12/30/2004
• Est. Priority Date: 05/16/2003
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nishikawa, Kenzo
• Granted Patent: US 7,990,883 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

In a self-organized distributed communication system utilizing a plurality of communication channels, improvement of a channel capacity is intended increase while using an access control method by carrier sensing. A station receives a beacon signal through each communication channel and grasps relative time information regarding to transmission/reception time of the beacon signal and communication channel information regarding a communication channel through which the beacon signal is transmitted/received. A new entry station obtains logical add (OR) of the grasped information to hold the time information and the communication channel information of the beacon signal. On transmitting/receiving data, the station switches the communication channel to use in accordance with the time information and the communication channel information to transmit a beacon signal to try communication.

Claims

1. A communication system forming a network having no relationship of a controlling station and a controlled station, in which a plurality of communication stations respectively operate in a self-organized distributed control manner, using a plurality of communication channels, wherein:

each of the communication stations manages at least time information concerning transmission/reception time of a beacon signal and communication channel information concerning a communication channel to use,

a transmitting communication station trying to transmit the beacon signal or data switches a communication channel to use in accordance with the time information and the communication channel information to transmit the beacon signal or the data, and

a receiving communication station trying to receive the beacon signal or data switches the communication channel to use in accordance with the time information and the communication channel information to receive the beacon signal or the data.

2. The communication system according to Claim 1, wherein each of said communication stations is capable of performing a reserved communication or a priority communication in the communication channel to use and manages a transmission/reception time in the reserved communication or the priority communication as said time information.

3. The communication system according to claim 1, wherein each of said communication stations notifies said time information and said communication channel information by describing in the beacon signal, and grasps a time and a communication channel at and through which the other communication station carries out communication in accordance with said time information and said communication channel information described in the beacon signal received from the other communication station.

4. The communication system according to claim 3, wherein each of said communication stations determines a time when the station itself transmits a beacon signal, a time when the station itself carries out data communication and a communication channel to use in accordance with said grasped time and communication channel at and through which the other communication station carries out communication.

5. The communication system according to claim 3, wherein a new entry communication station newly entering said network produces neighboring station time zone information regarding to a time zone already used by the other communication station by superposing said time information and said communication channel information described in the beacon signal received from the other communication station, and determines transmission time for transmitting a beacon signal of the new entry communication station and a communication channel used for transmitting the beacon signal.

6. The communication system according to claim 5, wherein said new entry communication station selects a time having a maximum interval during which no beacon signals are transmitted/received in the other communication station to determine as a transmission time of the beacon signal of the new entry communication station.

7. The communication system according to claim 6, wherein the new entry communication station divides said neighboring station time zone information into neighboring station time zone information of each communication channel, and evaluates a time having a maximum interval during which no beacon signals are transmitted/received in the other communication station at every communication channel to select a communication channel having the maximum interval during which no beacon signals are transmitted and received as a communication channel through which the new entry station transmits a beacon signal.

8. The communication system according to claim 3, wherein each of said communication stations determines s time when the station itself carries out the reserved communication or the priority communication and a communication channel to use for the reserved communication or the priority communication in accordance with said grasped time and communication channel at and through which the other communication station carries out communication.

9. The communication system according to claim 8, wherein a communication station trying to perform data communication with a specific communication destination:

produces neighboring station time zone information for every communication channel by superposing said time information and said communication channel information described in the beacon signal received from the other communication station at every communication channel,

obtains available time zone information regarding to a time zone available for communication with said communication destination for every communication channel by superposing time information in all communication channels of said communication destination on said neighboring station time zone information for every communication channel, and

determines a communication channel to use for communication with the communication destination and a time zone during which the communication is performed in accordance with said available time zone information for every communication channel.

10. The communication system according to claim 3, wherein each of said communication stations transmits data after grasping a maximum transmission available time being a maximum time available for data transmission in a transmission scheduled communication channel in accordance with time information regarding to a transmission/reception time of the beacon signal of the other communication station and time information regarding to a transmission/reception time of the beacon signal in the other communication channel of a transmission destination communication station.

11. The communication system according to claim 1, wherein, in said communication system, each of said communication stations transmits a packet having a preamble common to the other wireless communication systems and detects generation of a packet from another system depending on an error after the preamble in the received packet so as to change a communication channel in use.

12. The communication system according to claim 11, wherein each of said communication stations records occurrence frequency of packets from another system together with a reception time of each communication channel and uses the number of errors when the reception time exceeds a predetermined time period as an effective value in judgment for changing the communication channel.

13. The communication system according to claim 1, wherein, upon detecting an interference, a receiving communication station receiving data requests a transmitting communication station transmitting data through a communication channel on which the interference occurs to change the transmission time of the beacon signal and the communication channel to use.

14. The communication system according to claim 1, wherein, upon detecting an interference, a transmitting communication station transmitting data counts the number of times receiving no response from a data transmission destination station and requests changing of the transmission time of the beacon signal and the communication channel to use in response to a frequency of no response exceeding a predetermined value.

15. A communication method forming a network having no relationship of a controlling station and a controlled station, in which a plurality of communication stations respectively operate in a self-organized distributed control manner, using a plurality of communication channels, wherein:

each of the communication stations manages at least time information concerning a transmission/reception time of a beacon signal and communication channel information concerning a communication channel to be used,

a transmitting communication station trying to transmit the beacon signal or data switches a communication channel to be used in accordance with the time information and the communication channel information to transmit the beacon signal or the data, and

a receiving communication station trying to receive the beacon signal or data switches the communication channel to be used in accordance with the time information and the communication channel information to receive the beacon signal or the data.

16. The communication method according to claim 15, wherein each of the communication stations is capable of performing a reserved communication or a priority communication in the communication channel to be used and manages a transmission/reception time in the reserved communication or the priority communication as said time information.

19. The communication method according to claim 15, wherein:

said time information and said communication channel information are described in the beacon signal; and

a time and a communication channel at and through which the other communication station performs communication are grasped in accordance with said time information and said communication channel information described in the beacon signal received from the other communication station.

20. The communication method according to claim 19, wherein each of the communication stations determines a time for transmitting a beacon signal by itself, a time for performing data communication and a communication channel to use in accordance with said grasped time and communication channel at and through which the other communication station carries out communication.

21. The communication method according to claim 19, wherein, upon newly entering said network, each of the communication stations produces neighboring station time zone information regarding to a time zone already used by the other communication station by superposing said time information and said communication channel information described in the beacon signal received from the other communication station, and determines a transmission time of a beacon signal of the station itself and a communication channel to use for transmitting the beacon signal in accordance with the neighboring station time zone information.

22. The communication method according to claim 21, wherein, upon newly entering said network, each of the communication stations selects a time having a maximum interval during which no beacon signals are transmitted/received in the other communication station to determine as a transmission time of the beacon signal of the station itself in accordance with said neighboring station time zone information.

23. The communication method according to claim 22, wherein, upon newly entering said network, each of the communication stations divides said neighboring station time zone information into neighboring station time zone information of each communication channel, and evaluates a time having a maximum interval during which no beacon signals are transmitted/received in the other communication station at every communication channel to select a communication channel having the maximum interval during which no beacon signals are transmitted and received as a communication channel through which the station itself transmits a beacon signal.

24. The communication method according to claim 19, wherein each of the communication stations determines a time when the station itself carries out a reserved communication or a priority communication and a communication channel to use for the reserved communication or the priority communication in accordance with said grasped time and communication channel at and through which the other communication station carries out communication.

25. The communication method according to claim 24, wherein each of the communication stations, at a time trying to start data communication with a specific communication destination:

produces neighboring station time zone information for every communication channel by superposing said time information and said communication channel information described in the beacon signal received from the other communication station at every communication channel,

obtains available time zone information regarding to a time zone available for communication with said communication destination for every communication channel by superposing time information in all communication channels of said communication destination on said neighboring station time zone information for every communication channel, and

determines a communication channel to use for communication with the communication destination and a time zone during which the communication is performed in accordance with said available time zone information for every communication channel.

26. The communication method according to claim 19, wherein each of the communication stations transmits data after grasping a maximum transmission available time being a maximum time available for data transmission in a transmission scheduled communication channel in accordance with time information regarding to a transmission/reception time of the beacon signal of the other communication station and time information regarding to a transmission/reception time of the beacon signal in the other communication channel of a transmission destination communication station.

27. The communication method according to claim 15, wherein, in the communication system:

each of the communication stations transmits a packet having a preamble common to the other wireless communication systems, and

generation of a packet from another system is detected depending on an error in information after the preamble in the received packet so as to change a communication channel in use.

28. The communication method according to claim 27, wherein each of the communication stations records occurrence frequency of packets from another system together with a reception time of each communication channel and uses the number of errors when the reception time exceeds a predetermined time period as an effective value in judgment for changing the communication channel.

29. The communication method according to claim 15, wherein, upon detecting an interference, each of the communication stations requests a communication station transmitting data through a communication channel on which the interference occurs to change the transmission time of the beacon signal and the communication channel to use.

30. The communication method according to claim 15, wherein, upon detecting an interference, each of the communication stations counts the number of times receiving no response from a data transmitting communication station and requests changing of the transmission time of the beacon signal and the communication channel to use in response to a frequency of no response exceeding a predetermined value.

17. A communication apparatus the communication apparatus performing a network operation in a self-organized distributed manner without having no relationship of a controlling station and a controlled station in a communication environment having a plurality of communication stations, said apparatus comprising:

communication means for transmitting/receiving wireless data on a communication channel;

communication control means for setting a communication channel to use and controls data transmission/reception in the communication means;

beacon generating means for generating a beacon signal; and

beacon analyzing means for analyzing the beacon signal received from a neighboring station, wherein;

said communication control means at least manages time information regarding to a transmission/reception time of the beacon signal and communication channel information regarding to the communication channel to use, switches the communication channel to use in accordance with the time information or the communication channel information to transmit the beacon signal or data at the time of transmitting the beacon signal or the data, and switches the communication channel to use in accordance with the time information and the communication channel information to receive the beacon signal or the data at the time of receiving the beacon signal or the data.

18. The communication apparatus according to claim 17, wherein a reserved communication or a priority communication is possible in the communication channel to use, and said communication control means manages a transmission/reception time in the reserved communication or the priority communication as said time information.

31. A communication control method for performing a network operation in a self-organized distributed manner without having no relationship of a controlling station and a controlled station in a communication environment having a plurality of communication stations, said method comprising the steps of:

a beacon generating step of generating a beacon signal;

a beacon analyzing step of analyzing a beacon signal received from a neighboring station;

a step of managing at least time information regarding to transmission/reception time of the beacon signal and communication channel information regarding a communication channel to use;

a step of transmitting the beacon signal or data after switching the communication channel to use in accordance with said time information and said communication channel information at a time of transmitting the beacon signal or the data; and

a step of receiving the beacon signal or the data after switching the communication channel to use in accordance with said time information and said communication channel information at a time of receiving the beacon signal or the data.

32. A computer program described to be computer readable for executing on a computer a process for performing a network operation in a self-organized distributed manner without having no relationship of a controlling station and a controlled station in a communication environment having a plurality of communication stations, said method comprising the steps of:

a beacon generating step of generating a beacon signal;

a beacon analyzing step of analyzing a beacon signal received from a neighboring station;

a step of managing at least time information regarding to transmission/reception time of the beacon signal and communication channel information regarding a communication channel to use;

a step of transmitting the beacon signal or data after switching the communication channel to use in accordance with said time information and said communication channel information at a time of transmitting the beacon signal or the data; and

a step of receiving the beacon signal or the data after switching the communication channel to use in accordance with said time information and said communication channel information at a time of receiving the beacon signal or the data.