Contention-resolution system for a command- response data network

• US 7,035,276 B2
• Filed: 04/17/2002
• Issued: 04/25/2006
• Est. Priority Date: 04/17/2002
• Status: Expired due to Fees

• Current Assignee: United States Army (U.S. Department Of Defense)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Bradford, G. Patton, Pitruzzello, Michael C.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Fox, Jamal A.
• Application Number:
  US10/127,139
• Publication Number:
  US 20030198245A1
• Time in Patent Office: 1,469 Days
• Field of Search: 370/445, 370/431, 370/448, 370/447, 370/461, 370/463, 370/334, 370/328, 370/324, 370/350, 370/418, 370/395.62, 370/426, 370/496, 370/503, 370/507, 370/522, 370/525, 370/526, 370/518, 370/519, 370/277, 370/310, 370/489, 370/421, 370/423, 370/270, 370/326, 370/336, 370/376, 370/395.1, 370/398, 370/422, 370/458, 370/294, 370/321, 370/337, 370/347, 370/77, 370/85.2, 370/85.3, 370/498, 370/100.1, 370/103, 370/105, 370/110.2, 370/110.3, 370/414, 370/416, 375/130, 375/219, 375/220, 709/217, 709/218, 709/219, 709/230, 709/235
• US Class Current: 370/445
• CPC Class Codes: H04L 12/4035 in which slots of a TDMA packet structure are assigned based on a contention resolution carried out at a master unit TDM/TDMA multiplex systems per se H04J3/1694; hybrid switching systems H04L12/64
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

Applicants'"'"' Contention-Resolution System for a Command-Response Data Network uses a base unit (base) that detects the occurrence of collisions for the entire network and controls the maximum length of time allowed for the multiple remote units (remotes) in the network before re-trying to send responses to the base. The base either expands or contracts this maximum time delay as needed to accommodate the number of the possible network remotes, depending on the detected collision rate and the overall utilization of the network until the base determines that there are no remotes to be registered or all of the available network slots are filled, whichever occurs first.

Claims

1. A method for resolving contention among the signals traveling between a base and a plurality of remotes and among the signals from the plural remotes, in the process to register the remotes into a data network having a pre-determined number of network slots, said method utilizing radio frequency signals and comprising the steps of:

Broadcasting a hail signal from the base to initiate the registration process, said hail signal being intended for the remotes;

Allowing a pre-selected hail time to expire;

Calculating at the base maximum time delay signal, said time delay signal to be used by the remotes in responding to the base;

Transmitting said maximum time delay signal to the remotes;

Issuing a synchronization signal to the remotes;

Accepting at one or more remotes said maximum time delay signal and calculating therefrom a new random delay, said random delay having a time value ranging between “

0” and

said maximum;

Waiting for said synchronization signal to complete and said random delay to expire;

Sending to the base a response from one or more remotes, said response containing therein the unique address of its respective remote;

Receiving at the base said responses from one or more remotes and registering said remotes into the data network;

Conveying acknowledgment signals to the remotes, said acknowledgment signals indicating the registration of said remotes into the data network; and

Exiting the registration process.

2. A method for resolving contention among the signals traveling between a base and a plurality of remotes and among the signals from the plural remotes, in the process to register the remotes into a data network as set forth in claim 1, wherein said Receiving step at the base includes:

Returning to said Broadcasting step if no complete response has been received from at least one remote; and

Continuing the registration process therefrom until either no bytes are received or all of said network slots are filled.

3. A method for resolving contention as set forth in claim 2, wherein said Conveying step includes;

Determining at the remotes whether registration has occurred;

Awaiting a subsequent hail signal from the base if no registration has been detected; and

Proceeding with the registration process until an acknowledgment signal is received from the base indicating successful registration.

4. A method for resolving contention as set forth in claim 3, wherein said Calculating step utilizes a dynamic back-off approach, on a per-cycle basis, factoring into the calculation the network loading conditions and bandwidth utilization.

5. A method for resolving contention as set forth in claim 3, wherein said Calculating step utilizes a fixed back-off schedule, said schedule being pre-programmed into the base and the remotes.

6. A system for detecting collisions and resolving contention between command and response signals in a registration process into a data network, said system comprising:

a base unit, said base unit being capable of initiating the registration process by issuing hail signals, followed by maximum delay signals;

a plurality of remote units to be registered into said data network, said remote units each having a unique address and responding to said hail signals by transmitting response signals containing their respective addresses to said base unit, said base unit registering said remote units upon receipt of complete responses therefrom.

7. A system for detecting collisions and resolving contention between command and response signals in a registration process into a data network as set forth in claim 6, wherein said system further comprises:

a first antenna coupled to said base unit for broadcasting said hail and maximum delay signals and for receiving any incoming signals; and

a plurality of second antennas, each of said second antennas being coupled to one of said remote units for receiving signals emanating from said base unit and transmitting said response signals from said remote unit.

8. A system for detecting collisions and resolving contention between command and response signals in a registration process into a data network as set forth in claim 7, wherein said base unit comprises:

a first computer for generating said hail and maximum delay signals; and

a first radio frequency (RF) transceiver coupled to said first computer, said first transceiver broadcasting said hail and maximum delay signals.

9. A system for detecting collisions and resolving contention between command and response signals as set forth in claim 8, wherein each of said plural remote units comprises:

a second RF transceiver; and

a second computer, said second computer being coupled to said second transceiver and generating said response signals containing said address and transmitting said response signals to said second transceiver to be broadcast therefrom.

10. A system for detecting collisions and resolving contention between command and response signals as set forth in claim 9, wherein said base unit produces synchronization signals to synchronize the broadcast of said response signals from said remote units, said synchronization signals cooperating with said maximum delay signals to minimize collisions between said base unit-generated signals and said remote unit-generated signals as well as between said remote unit-generated signals from said plurality of remote units.

11. A system for detecting collisions and resolving contention between command and response signals as set forth in claim 10, wherein said second computer has residing therein information regarding pre-selected back-off schedule.

12. A system for detecting collisions and resolving contention between command and response signals as set forth in claim 11, wherein said data network has a predetermined number of slots and wherein said base unit terminates said registration process when no remote unit-generated signals are received or when all of said slots are filled with remote unit addresses.

13. A system for detecting collisions and resolving contention between command and response signals as set forth in claim 12, wherein said base unit generates said maximum delay signals based on a dynamic back-off approach.

14. A system for detecting collisions and resolving contention between command and response signals as set forth in claim 12, wherein said base unit generates said maximum delay signals based on a common back-off schedule, said schedule being programmed into said base unit and said plurality of remote units prior to commencement of said registration process.