Communication medium access control protocol for wireless communication

• US 5,502,724 A
• Filed: 11/14/1994
• Issued: 03/26/1996
• Est. Priority Date: 11/15/1993
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Maryan, Jacek P., Chen, Jeane S., Hartlen, Bryan R., Kurata, Tom D., Frickes, Stanley L., Williams, Timothy F., McKay, Dan N.
• Primary Examiner(s): Chin, Wellington
• Application Number:
  US08/338,715
• Time in Patent Office: 498 Days
• Field of Search: 370/85.1, 370/85.2, 370/85.3, 370/85.4, 370/85.5, 370/85.15, 370/94.1, 370/94.2, 370/95.1, 370/95.3, 370/110.1, 370/85.7
• US Class Current: 370/445
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]

Abstract

A method is provided for controlling access to a communication medium intended for sharing by a least two stations to enable peer-to-peer communications therebetween. Initially, the communication medium is sensed at a first station to determine if the medium is in use. If the first station senses that the medium is not in use, the first station may then transmit a connection request message intended for a second station. Upon receiving at the second station the connection request message, the second station transmits a connection confirm message to the first station for the purpose of establishing a reservation of the transmission medium for use by the first and second stations. Thereafter, the first station transmits information as one or more data messages from the first station to the second station. Upon receiving the last of the data messages from the first station, the second station transmits an acknowledgement message to the first station. The first station, upon receiving the acknowledgement message, subsequently transmits a disconnect request message to the second station. Upon receiving the disconnect request message, the second station subsequently transmits a disconnect confirm message for reception by the first station for the purpose of ending the reservation of the medium.

Claims

1. A method for controlling access to a communication medium intended for sharing by at least two stations for peer-to-peer communications therebetween, said method comprising the steps of:

sensing said communication medium at a first station to determine if said communication medium is in use;

transmitting a connection request message from said first station to a second station if said first station determines that said communication medium is not in use;

transmitting a connection confirm message from said second station to said first station for temporarily reserving said communication medium for use by only said first and second stations;

transmitting data messages from said first station to said second station;

transmitting an acknowledgement message from said second station to said first station in response to said second station receiving a last one of said data messages;

transmitting a disconnect request message from said first station to said second station in response to receiving said acknowledgement message; and

transmitting a disconnect confirm message from said second station to said first station in response to receiving said disconnect request message for terminating said reservation of said communication medium.

2. The method according to claim 1 further including the step of placing a third station in a wait state until the occurrence of a predetermined event, wherein said third station is restrained from transmitting messages on said communication medium while in said wait state.

3. The method according to claim 2 further including the step of maintaining said wait state until said third station detects termination of said reservation of said communication medium, or until a wait state timer expires.

4. The method according to claim 3 further including the step of maintaining said wait state until said wait state timer expires, or until said third station detects either said disconnect request message or said disconnect confirm message.

5. The method according to claim 2 further including the step of placing said third station in an idle state from said wait state in response to the occurrence of said predetermined event.

6. The method according to claim 1 wherein said data messages include sequence information for identifying said data messages, and wherein said step of transmitting data messages from said first station to said second station includes transmitting data messages having said sequence information from said first station to said second station.

7. The method according to claim 6 wherein said sequence information includes a total number of said data messages to be transmitted from said first station to said second station.

8. The method according to claim 7 further including the step of identifying, within said second station, a last data message by utilizing said sequence information.

9. The method according to claim 1 further including the step of placing each station accessing said communication medium in a state in which it is free to secure a reservation of said communication medium, in response to termination of said reservation by said first and second stations.

10. The method according to claim 9 wherein said step of placing each station accessing said communication medium in a state in which it is free to secure a reservation of said communication medium, in response to termination of said reservation by said first and second stations includes placing each station accessing said communication medium in a state in which it is free to secure a reservation of said communication medium, in response to termination of said reservation by said first and second stations, and expiration of a preselected period of time preselected for each station.

11. The method according to claim 10 wherein said preselected period of time includes a random delay.

12. A communications system for controlling access to a communication medium intended for sharing by at least two stations for peer-to-peer communications therebetween, said communications system comprising:

means for sensing said communication medium at a first station to determine if said communication medium is in use;

means for transmitting a connection request message from said first station to a second station if said first station determines that said communication medium is not in use;

means for transmitting a connection confirm message from said second station to said first station for temporarily reserving said communication medium for use by only said first and second stations;

means for transmitting data messages from said first station to said second station;

means for transmitting an acknowledgement message from said second station to said first station in response to said second station receiving a last one of said data messages;

transmitting a disconnect request message from said first station to said second station in response to receiving said acknowledgement message; and

transmitting a disconnect confirm message from said second station to said first station in response to receiving said disconnect request message for terminating said reservation of said communication medium.

13. The communications system according to claim 12 further including means for placing a third station in a wait state until the occurrence of a predetermined event, wherein said third station is restrained from transmitting messages on said communication medium while in said wait state.

14. The communications system according to claim 13 further including means for maintaining said wait state until said third station detects termination of said reservation of said communication medium, or until a wait state timer expires.

15. The communications system according to claim 14 further including means for maintaining said wait state until said wait state timer expires, or until said third station detects either said disconnect request message or said disconnect confirm message.

16. The communications system according to claim 13 further including means for placing said third station in an idle state from said wait state in response to the occurrence of said predetermined event.

17. The communications system according to claim 12 wherein said data messages include sequence information for identifying said data messages, and wherein said means for transmitting data messages from said first station to said second station includes means for transmitting data messages having said sequence information from said first station to said second station.

18. The communications system according to claim 17 wherein said sequence information includes a total number of said data messages to be transmitted from said first station to said second station.

19. The communications system according to claim 18 further including means for identifying, within said second station, a last data message by utilizing said sequence information.

20. The communications system according to claim 12 further including means for placing each station accessing said communication medium in a state in which it is free to secure a reservation of said communication medium, in response to termination of said reservation by said first and second stations.

21. The communications system according to claim 20 wherein said means for placing each station accessing said communication medium in a state in which it is free to secure a reservation of said communication medium, in response to termination of said reservation by said first and second stations includes means for placing each station accessing said communication medium in a state in which it is free to secure a reservation of said communication medium, in response to termination of said reservation by said first and second stations, and expiration of a preselected period of time preselected for each station.

22. The communications system according to claim 21 wherein said preselected period of time includes a random delay.