Channel hopping protocol

• US 6,292,494 B1
• Filed: 12/19/1997
• Issued: 09/18/2001
• Est. Priority Date: 12/24/1996
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Baker, Murray C., Wallaker, Aron D., Chau, Alan C., Taglione, John V.
• Primary Examiner(s): Marcelo, Melvin
• Assistant Examiner(s): Nguyen, Phuongchau Ba
• Application Number:
  US08/994,297
• Time in Patent Office: 1,369 Days
• Field of Search: 370/322, 370/338, 370/445, 370/447, 370/448, 370/461, 370/462, 370/471, 370/474, 370/459, 375/132, 375/356, 375/364, 375/134, 375/137, 375/347, 340/825.5, 340/825.25
• US Class Current: 370/459
• CPC Class Codes: H04B 1/713 using frequency hopping

Abstract

A method and means for information transmission over a medium for a wireless communication system comprising a network of stations capable of sending and receiving data transmissions over a number of communication channels. The method includes sending a data transmission in a packet including a header and a data portion, the header includes identification (ID) of the network; identification of the next channel to be used in communications; an address; a channel busy count field; and a network command.

Claims

1. A method of information transmission over a medium for a wireless communication system comprising a network of stations capable of sending and receiving data transmissions over a number of communication channels of said medium, comprising:

assembling a data packet comprising a header and a data portion, said header comprising identification (ID) of said network, identification of the next channel to be used in communications, an address, a channel busy count field, a network command, and said data portion comprising data; and

sending said data packet.

2. The method of claim 1 wherein said address comprises the specific address of a receiving station of the network at which information in the transmission is intended to be received.

3. The method of claim 1 wherein said address comprises a broadcast address which enables all the stations of the network to receive said information in said transmission.

4. The method of claim 2 in which said data portion of said packet comprises a data packet for another network to which said receiving station is connected for processing by said receiving station.

5. The method of claim 4 wherein said data packet comprises a token ring packet for use in a token ring network.

6. The method of claim 4 wherein said data packet comprises a Ethernet packet for use in an Ethernet network.

7. The method of claim 1 in which each station in said network maintains a channel hopping table which indicates the sequence of channels to be followed for transmission.

8. The method of claim 7 in which said channel hopping table includes a channel busy field/count.

9. The method of claim 8 further comprising the steps at each station of:

listening for activity on a current channel;

sending a synchronization request transmission if no activity is detected within a preset time;

waiting for an acknowledgement to said synchronization request transmission;

choosing the next channel on said channel hopping table if no acknowledgement is received;

repeating said sending, waiting and choosing until an acknowledgement is received on a chosen channel; and

synchronizing on said chosen channel once an acknowledgment has been received.

10. The method of claim 9 further comprising, upon detection of activity on a channel, said station attempting to decipher the header of a detected transmission packet.

11. The method of claim 10 further comprising said station marking said channel as inoperative if said attempting to decipher fails.

12. The method of claim 11 in which said station maintains a bad channel counter and wherein said marking comprises incrementing said bad channel counter each time a problem with the detection of a suitable signal is encountered;

and marking said channel inoperative if said bad channel counter reaches a predetermined counter limit.

13. The method of claim 12 further comprising resetting said bad channel counter to zero if said channel is subsequently used successfully.

16. The method of claim 7 wherein said channels in said channel hopping table are contiguous but ordered using a pseudo-random generator which makes use of the ID of the network as a seed to generate the order of channels in said channel hopping table.

14. A method for a station having a first domain ID to join a network comprising the steps of:

monitoring channel activity for at least one transmissions including at least one transmission domain ID;

upon detection of a transmission, determining if said transmission domain ID matches said first domain ID;

joining the network communicating on said channel if said transmission domain ID matches said first domain ID;

sending a synchronization request of the network medium if said transmission domain ID does not match said first domain ID;

waiting for an acknowledgement having an acknowledgement domain ID upon said sending;

comparing said acknowledgement domain ID to said first domain ID; and

joining the network communicating on said channel if said acknowledgement domain ID matches said first domain ID.

15. The method of claim 14 comprising, after joining said network, said station sending packets of information to other stations on said networks and receiving packets of information from other stations on said network.

17. A communication network in which at least one data transmission is conveyed over a number of wireless channels to a plurality of stations in said network comprising:

means for establishing a channel hopping table in each station, said table including a plurality of channels including a first and a plurality of successive channels;

means for selecting the next successive channel for communication in said table in response to receipt of instructions from one of said plurality of stations;

means for selecting the next successive channel in the table in response to a lapse of a predetermined time period between detection of decipherable signals along one of said plurality of channels;

means for indicating that specific channels in the table are inoperative; and

means for accessing previously indicated inoperative channels when the number of inoperative channels falls below a predetermined threshold.

18. Apparatus as in claim 17 wherein said means for establishing said table comprises a pseudo-random generator adapted to use the ID of a network as a seed for generating the order of channels in said table.

19. The apparatus in claim 17 wherein said apparatus comprises at least one storage medium containing program modules for the establishment of said means indicated.

20. A program product comprising:

a data processing machine-useable medium having machine readable program code means embodied therein for enabling data transmission of a network station over a number of wireless channels in a medium, the program code means in said computer program product comprising;

program code means for establishing a channel hopping table in each station;

program code means for selecting the next operative channel for communication in said table in response to receipt of instructions from another station;

program code means for selecting the next channel in the table in response to a lapse of a predetermined time period between detection of decipherable signals;

program code means for indicating that specific channels in the table are inoperative;

program code means for accessing previously indicated inoperative channels when the number of inoperative channels falls below a predetermined threshold.

21. The program of claim 20 wherein said program code means for establishing said table comprises a program code means for establishing a pseudo-random generator adapted to use the ID of a network as a seed for generating the order of channels in said table.