Wireless communication system, wireless communication apparatus, wireless communication method and computer program

• US 7,565,109 B2
• Filed: 07/26/2004
• Issued: 07/21/2009
• Est. Priority Date: 07/29/2003
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Morioka, Yuichi, Nishikawa, Kenzo
• Primary Examiner(s): Appiah; Charles N
• Assistant Examiner(s): Peaches; Randy
• Application Number:
  US10/898,227
• Publication Number:
  US 20050058117A1
• Time in Patent Office: 1,821 Days
• Field of Search: 455/454, 455/444, 455/41.2, 455/41.3, 455/67.11, 455/63.1, 455/63.2, 455/63.3, 370/338, 370/252, 370/216, 709/230
• US Class Current: 455/63.1
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A deadlocked state in which each communication station cannot recognize mutual existence is evaded to form a self-organized distribution type multi-channel wireless network. In some interference situations, a beacon transmission channel selected on a self criterion is not always a receivable channel for all of neighbor communication stations. A communication station receiving interference from another system periodically transmits an interference annunciation signal (IAS) through all channels under no interference, and informs the neighbor stations of the existence and the channel under interference. Thereby, transmission of a beacon is restrained through the channel under interference up to a beacon-unhearable degree.

Claims

1. A wireless communication system for forming a network based on ad hoc communication by a plurality of wireless communication stations without arranging a control station in a communication environment provided with a plurality of channels, each of said plurality of wireless communication stations comprising:

a beacon transmission unit configured to transmit a beacon at a predetermined beacon period through its own beacon transmission channel; and

an interference annunciation signal transmitting unit configured to transmit an interference annunciation signal describing information related to a channel under interference of a local station through another usable channel at a predetermined period.

2. The wireless communication system according to claim 1, wherein each of said communication stations further comprises:

a channel scanner configured to perform a channel scanning operation of each channel at a period which does not synchronize with a transmission period of the interference annunciation signal.

3. The wireless communication system according to claim 1, wherein each of said communication stations further comprises:

a comparator configured to compare interference information of each channel of a neighbor station, the information described in the interference annunciation signal received from the neighbor station with a beacon transmission channel of the local station; and

a channel changer configured to change the beacon transmission channel of the local station to a channel through which the neighbor station can easily listen to the beacon of the local station when it becomes clear that the beacon is transmitted through a channel on which an interference level is high.

4. A wireless communication apparatus operating in a self-organized distributed manner in a wireless communication environment, said apparatus comprising:

interference annunciation signal generation means for generating a beacon signal indicating a channel currently being used for transmission by a local station and an interference annunciation signal indicating interference levels received by the local station on a plurality of channels;

communication means for transmitting and receiving wireless data through each channel;

interference annunciation signal analysis means for analyzing the beacon signal and the interference annunciation signal of a neighbor station, the signals received by said communication means;

channel setting means for setting data transmission and reception channel in said communication means; and

communication control means for controlling a transmission operation of the beacon signals and the interference annunciation signals of the local station in said communication means, and a reception operation of the beacon signals and the interference annunciation signals from said neighbor station.

5. The wireless communication apparatus according to claim 4, wherein said channel setting means determines its own beacon transmission channel among the plurality of channels, and sets a channel other than the beacon transmission channel as a transmission channel of the interference annunciation signal.

6. The wireless communication apparatus according to claim 5, wherein said channel setting means excludes a channel under interference of the local station from the beacon transmission channel and the transmission channel of the interference annunciation signal.

7. The wireless communication apparatus according to claim 4, wherein said communication control means controls a channel scanning operation of each channel at a period which does not synchronize with a transmission period of the interference annunciation signals.

8. The wireless communication apparatus according to claim 4, wherein said interference annunciation signal analysis means compares interference information of each channel of the neighbor station, the information described in the interference annunciation signal received from the neighbor station, with a beacon transmission channel of the local station, and said channel setting means changes a beacon transmission channel of the local station to a channel through which the neighbor station can easily listen to the beacon when it becomes clear that the beacon is transmitted through a channel on which an interference level of the neighbor station is high on a basis of a result of the comparison.

9. The wireless communication apparatus according to claim 4, wherein, in a case where there are no channels under interference of the local station, said communication control means does not transmit the interference annunciation signal, or said interference annunciation signal generation means does not generate the interference annunciation signal.

10. The wireless communication apparatus according to claim 4, wherein, when it becomes clear that there are neighbor stations having a same channel under interference as a result of an analysis by said interference annunciation signal analysis means, said communication control means adjusts a transmission frequency of the interference annunciation signal according to a number of said neighbor stations to transmit the interference annunciation signal.

11. The wireless communication apparatus according to claim 4, wherein said communication control means increases a transmission frequency of the interference annunciation signals for a predetermined time period in response to entering of a new communication station.

12. The wireless communication apparatus according to claim 11, further comprising:

means for informing the neighbor station of entering of a new communication station when the entering is discovered,

wherein said communication control means increases the transmission frequency of the interference annunciation signal for the predetermined time period in response to information indicating the entering of said new communication station.

13. The wireless communication apparatus according to claim 11, wherein said communication control means gradually decreases the transmission frequency of the interference annunciation signal from an initial value according to elapsed time from the entering of the new communication station.

14. A wireless communication method operating in a self-organized distributed manner in a wireless communication environment, said method comprising:

generating a beacon signal indicating a channel currently being used for transmission by a local station and an interference annunciation signal indicating interference levels received by the local station on a plurality of channels;

analyzing the beacon signal and the interference annunciation signal, both received from a neighbor station;

setting a data transmission and reception channel; and

controlling a transmission operation of the beacon signals and the interference annunciation signals of the local station, and a reception operation of the beacon signals and the interference annunciation signal from the neighbor station.

15. The wireless communication method according to claim 14, wherein said setting includes determining an own beacon transmission channel among the plurality of channels, and a channel other than the beacon transmission channel is set as a transmission channel of the interference annunciation signal.

16. The wireless communication method according to claim 15, wherein said setting, includes excluding the channel under the interference of the local station from the beacon transmission channel and the transmission channel of the interference annunciation signal.

17. The wireless communication method according to claim 14, wherein said controlling includes controlling a channel scanning operation of each channel at a period which does not synchronize with a transmission period of the interference annunciation signals.

18. The wireless communication method according to claim 14, wherein said analyzing includes comparing interference information of each channel of the neighbor station, the information described in the interference annunciation signal received from the neighbor station, with a beacon transmission channel of the local station, and

said setting includes changing a beacon transmission channel of the local station to a channel through which the neighbor station can easily listen to the beacons when it becomes clear that the beacons are transmitted through a channel on which an interference level of the neighbor station is high on a basis of a result of the comparing.

19. The wireless communication method according to claim 14, wherein, in a case where there are no channels under interference of the local station, said controlling includes not transmitting the interference annunciation signal, or said generating includes not generating the interference annunciation signal.

20. The wireless communication method according to claim 14, wherein said controlling includes adjusting a transmission frequency of the interference annunciation signal according to a number of the neighbor stations to transmit the interference annunciation signal when the analyzing shows that a neighbor station has a same channel under interference.

21. The wireless communication method according to claim 14, wherein said controlling includes increasing a transmission frequency of the interference annunciation signals for a predetermined time period in response to entering of a new communication station.

22. The wireless communication method according to claim 21, further comprising:

informing the neighbor station of the entering of the new communication station when the entering is discovered,

wherein said controlling includes increasing the transmission frequency of the interference annunciation signal for the predetermined time period in response to information indicating the entering of the new communication station.

23. The wireless communication method according to claim 21, wherein said controlling includes gradually decreasing the transmission frequency of the interference annunciation signal from an initial value according to elapsed time from the entering of the new communication station.

24. A computer readable medium including computer executable instructions, wherein the instructions, when executed by a processor, cause the processor to perform a method comprising:

generating a beacon signal indicating a channel currently being used for transmission by a local station and an interference annunciation signal indicating interference levels received by the local station on a plurality of channels;

analyzing the beacon signal and the interference annunciation signal, both received from a neighbor station;

setting a data transmission and reception channel; and

controlling a transmission operation of the beacon signal and the interference annunciation signal of the local station, and a reception operation of the beacon signal and the interference annunciation signal from the neighbor station.

25. A wireless communication apparatus operating in a self-organized distributed manner in a wireless communication environment, said apparatus comprising:

an interference annunciation signal generation unit configured to generate a beacon signal indicating a channel currently being used for transmission by a local station and an interference annunciation signal indicating interference levels received by the local station on a plurality of channels;

a communication unit configured to transmit and receive wireless data through each channel;

an interference annunciation signal analysis unit configured to analyze the beacon signal and the interference annunciation signal of a neighbor station, the signals received by said communication unit;

a channel setting unit configured to set data transmission and reception channel in said communication unit; and

a communication control unit configured to control a transmission operation of the beacon signals and the interference annunciation signals of the local station in said communication unit, and a reception operation of the beacon signals and the interference annunciation signals from said neighbor station.