Dual mode of operation multiple access system for data link communication

• US 6,847,619 B2
• Filed: 05/11/2001
• Issued: 01/25/2005
• Est. Priority Date: 05/11/2001
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Reid, Ryan Christopher, Zscheile, John Walter Jr., Buzby, John Schofield Jr.
• Primary Examiner(s): Ho, Duc
• Assistant Examiner(s): Nguyen, Phuongchau Ba
• Application Number:
  US09/854,104
• Publication Number:
  US 20020167959A1
• Time in Patent Office: 1,355 Days
• Field of Search: 370/310, 370321-324, 370/345, 370/347, 370/348, 370/442, 370/443, 370/444, 370/458, 370/459, 370/461, 370/462, 455/436, 455/450, 455/455, 455/435.3, 455/417
• US Class Current: 370/322
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04B 7/2125 Synchronisation
• CPC Class Codes: H04W 74/02 Hybrid access

Abstract

In a data link communications system there is provided a dual mode of operation multiple access system for communication between a plurality of spoke stations and a central hub station which generates a spoke epoch time comprising a plurality of time division slots in which a spoke station can communicate a priority interrupt request to the central hub station. The spoke epoch time comprises one or more dedicated spoke time slots in which only one hub station may transmit to the hub station to the exclusion of all other spoke stations. The spoke epoch time further comprising one or more priority interrupt request time slots in which all spoke stations can transmit priority interrupt requests to the hub station. Controller means in the hub station provides for evaluating priority interrupt requests from the spoke stations and for granting transmission access to one of said spoke stations during predetermined time slots in the next spoke epoch time.

Claims

1. A dual protocol mode of operation multiple access system for spread spectrum data link communication between a central hub station and a plurality of spoke stations, comprising:

means in said spoke stations for generating priority request interrupts during a spoke epoch time having a plurality of time division slots,

said spoke epoch time comprising one or more dedicated spoke time slots in which each spoke stations can transmit data or requests with priorities to said central hub station to the exclusion of all other spoke stations,

said spoke epoch time further comprising one or more spoke priority interrupt request time slots in which all spoke stations can simultaneously transmit spread spectrum priority interrupt requests to said central hub station without collisions,

controller means in said central hub station for evaluating said plurality of spoke station interrupt requests,

means in said central hub station for granting transmission access to one of said spoke stations requests during predetermined time slots in the next spoke epoch time to the exclusion of all other spoke stations, and

said means for granting transmission access including means for resynchronizing timing in said spoke station.

2. A dual mode of operation multiple access system as set forth in claim 1 wherein said spoke epoch time includes at least one dedicated spoke time slot and at least one spoke priority interrupt request time slot.

3. A dual mode of operation multiple access system as set forth in claim 2 which further includes means in said spoke stations for generating a message length and a priority with each interrupt request.

4. A dual mode of operation multiple access system as set forth in claim 1 wherein said means for generating a priority interrupt request comprises means for delaying different priorities by different time amounts.

5. A dual mode of operation multiple access system as set forth in claim 4 wherein the highest priority interrupt request is delayed the least amount of time and lesser priorities are delayed increasing amounts of time.

6. A dual mode of operation multiple access system as set forth in claim 4 wherein said hub station controller comprises means for assigning spoke time slots to any time division slot in a spoke epoch time.

7. A dual mode of operation multiple access system as set forth in claim 6 wherein said hub station controller assigns all available time division slots of a spoke epoch to different spoke stations and a mode of operation emulates a Time Division Multiple Access (TDMA) mode of operation with a priority interrupt.

8. A dual mode of operation multiple access system as set forth in claim 6 wherein said hub station controller assigns all available time division slots to the transmission of data from spoke stations and the mode of operation emulates a Request Assigned Multiple Access with Priority Interrupt (RAMAPI) mode of operation.

9. A dual mode of operation multiple access system as set forth in claim 6 wherein said hub station controller may assign any available time slot to different spoke stations for a TDMA mode of operation or to data transmission from said spoke stations in a RAMAPI mode of operation so as to emulate one of two modes of operation or incorporate both modes of operation.

10. A dual mode of operation multiple access system as set forth in claim 1 which further comprises means in selective ones of said spoke stations for generating an override priority request in any time slot except the dedicated time slots of the spoke epochs used for resynchronizing timing.

11. A variable dual mode of operation multiple access system for optimizing spread spectrum data transmission between a central hub station and a plurality of spoke stations, comprising:

a hub station controller for generating a spoke epoch of synchronized spread spectrum time division slots,

at least one of said spokes epoch of synchronized spread spectrum time division slots including means for a spoke station to generate a priority interrupt,

said operation multiple access system being operable in a TDMA mode of operation when all said spoke epoch of synchronized spread spectrum time division slots are unique priority interrupt slots, wherein said spoke epoch of synchronized spread spectrum time division slots comprising one or more dedicated spoke time slots in which each spoke stations can transmit data or request with priority to said central hub station to the exclusion of all other spoke stations,

said spoke epoch of synchronized spread spectrum time divisions slots further comprising one or more spoke priority interrupt request time slots in which all spoke stations can simultaneously transmit spread spectrum priority interrupt requests to said central hub station without collisions,

means for resynchronized spectrum timing in said from said central hub station, and

said operation multiple access system being operable in a RAMAPI mode of operation when most of said time division slots are assigned to specific spoke stations for transmission of data from a spoke station to said central hub station.

12. A method of transmitting data from a plurality of spoke stations to a hub station using dual modes of operation, comprising the steps of:

transmitting data from said hub station to all spoke stations,

transmitting synchronized data from said spoke stations to said hub station only when the hub station assigns time slots for the spoke stations to transmit data to said hub station,

transmitting synchronized spread spectrum priority interrupt requests from said spoke stations to said hub station during a predetermined time slot or slots without collisions,

determining from the plurality of all priority interrupt requests the spoke station having the highest priority,

said hub station assigning to the spoke station with the highest priority a plurality of time slots all of its data and means for synchronizing its spread spectrum timing, and

said spoke station transmitting all of its synchronized data to said hub station during the plurality throughout a spoke epoch time.

13. The method as set forth in claim 12 which further comprises the steps of determining from data transmitted from said spoke stations an optimum data rate of transmission, and

said hub station further providing to said spoke stations the optimum data rate for the transmission of data.

14. The method as set forth in claim 12 which further includes steps of assigning only one time slot to spoke stations and one time slot for priority interrupt requests and assigning the remaining available time slots to specific spoke stations for transmission of data to the hub station for operation in a RAMAPI mode of operation.

15. The method as set forth in claim 12 which further includes the steps of assigning all available time slots to different spoke stations for transmission of data to the hub station for operation in the TDMA mode of operation.

16. The method as set forth in claim 12 which further includes the step of generating a priority override signal to designated ones of said spoke stations during any time slot other than time slots used for resynchronizing timing.

17. The method as set forth in claim 16 which further includes the step at the hub station of transmitting override priority data to an intended spoke station and informing other spoke stations that an override priority interrupt has occurred.

18. The method as set forth in claim 17 which further includes the step of reassigning time slots to the spoke stations for transmitting data that was interrupted by the override interrupt.

19. The method as set forth in claim 12 which further includes the steps of reassigning spoke station dedicated time slots and priority interrupt time slots throughout a spoke epoch time.