Claims
- 1. A method for managing collisions in a wireless detection system, said system comprising a plurality of receivers having a sending receiving module and at least one sending receiving unit for intermittent communication, via an on off switching cycle within a cycle, with said receivers located in a detection zone, comprising the steps of:
transmitting a broadcast message from said sending receiving unit to at least one receiver and transmitting a quittance message to said sending receiving unit from a quittance device associated with said detection zone; transmitting a presence message identifying said at least one receiver to said sending receiving unit, said message being transmitted by said at least one receiver upon receipt of said broadcast message, said message being transmitted after a time determined by a random generator; transmitting an acknowledgement message from said sending receiving unit to said at least one receiver, said acknowledgement message acknowledging receipt of said presence message; and if a collision occurs in the communication between said at least one receiver and said sending receiving unit, said collision is eliminated by:
repeating said step of transmitting a broadcast message if said quittance message is not received by said at least one receiver within a select cycle; and repeating said step of transmitting a presence message, at a random time generated by a random generator, if said acknowledgement message is not received by said at least one receiver within a latency time after said step of transmitting a presence message.
- 2. The method according to claim 1, wherein messages are only transmitted if prior to transmission an indication that a radio medium is available is detected.
- 3. The according to claim 1, further comprising the step of increasing the upper limit of the random generator with each repetition of said step of repeating said step of transmitting.
- 4. The according to claim 2, further comprising the step of increasing the upper limit of the random generator with each repetition of said step of repeating said step of transmitting.
- 5. The method according to claim 1, wherein said on off switching cycle and said cycle are individually determined by said sending receiving unit.
- 6. The method according to claim 4, wherein said on off switching cycle and said cycle are individually determined by said sending receiving unit.
- 7. The method according to claim 1, wherein said cycle is integrated into an anti-collision grid, whereby said cycle is a multiple of said anti-collision grid and message transmitted at transmission times determined by anti-collision grid.
- 8. The method according to claim 6, wherein said on off switching cycle and said cycle are individually determined by said sending receiving unit.
- 9. The method according to claim 1, wherein another on off switching cycle is associated with said cycle.
- 10. The method according to claim 8, wherein another on off switching cycle is associated with said cycle.
- 11. The method according to claim 1, further comprising the steps of altering said on off switching cycle in response to a transmission of said broadcast message from said sending receiving unit to said at least one receiver located in said detection zone.
- 12. The method according to claim 10, further comprising the steps of altering said on off switching cycle in response to a transmission of said broadcast message from said sending receiving unit to said at least one receiver located in said detection zone.
- 13. The method according to claim 1, further comprising the steps of resynchronizing a clock generator located in said at least one receiver upon transmission of said broadcast message.
- 14. The method according to claim 12, further comprising the steps of resynchronizing a clock generator located in said at least one receiver upon transmission of said broadcast message.
- 15. The method according to claim 1, wherein said communication is set up upon an alternative cycle if a collision is detected.
- 16. The method according to claim 14, wherein said communication is set up upon an alternative cycle if a collision is detected.
- 17. The method according to claim 15, wherein said alternative cycle is integrated into a second anti collision grid wherein a second anti collision grid cycle is a multiple of said second anti collision grid and messages are transmitted at times according to said second anti collision grid.
- 18. The method according to claim 1, wherein said communication is set up upon another frequency if a collision is detected.
- 19. Method according to claim 1, wherein times produced by said random generator are dependant upon identity of a corresponding receiver.
- 20. The method according to claim 17, wherein said communication is set up upon another frequency if a collision is detected and wherein times produced by said random generator are dependant upon identity of a corresponding receiver.
Priority Claims (1)
Number |
Date |
Country |
Kind |
EP00108905.1 |
Apr 2000 |
EP |
|
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of international patent application PCT/EPO1/00892, filed 27 January, 2001 and further claims priority to European patent application EP00108905.1, filed 27 April, 2000, both of which are incorporated herein by reference.
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/EP01/00892 |
Jan 2001 |
US |
Child |
10280059 |
Oct 2002 |
US |