Method for controlling the scheduling of multiple access to communication resources

• US 5,142,533 A
• Filed: 03/28/1991
• Issued: 08/25/1992
• Est. Priority Date: 03/28/1991
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Crisler, Kenneth J., Needham, Michael L.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US07/676,653
• Time in Patent Office: 516 Days
• Field of Search: 370/95.1, 370/85.2, 370/87.7, 370/95.3, 370/104.1
• US Class Current: 370/349
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04L 12/407 with decentralised control
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A method of providing a communication unit (10) access to a shared communication resource. In the communication unit, a clock (123) is maintained, and the unit detects the time when an inhibit period on the shared communication resource begins, and the time at which it concludes. When access to the shared communication resource is desired, the unit attempts to access the communication resource based on the time at which access was desired, as well as the times at which a detected inhibit condition began and concluded. A virtual time clock runs only during non-inhibit periods. Access to the communication resource is then based on when the virtual time clock equals the desired access time.

Claims

1. A method of accessing a shared communication resource, comprising the steps of:

in a communication unit;

A) maintaining a clock;

B) determining that an inhibit condition on the shared cummunication resource will occur, and then determining when the inhibit condition begins;

C) determining when the inhibit condition concludes;

D) determining when access to the shared communication resource by the communication unit is desired;

E) attempting to access the shared communication resource as a function of;

i) the beginning and concluding times of at least one of the detected inhibit conditions; and

ii) when access to the shared communication resource was desired.

2. The method claim 1, wherein step B includes the steps of:

B1) determining when the communication resource is scheduled for a reserved state;

B2) when the communication resource begins the reserved state, determining that the inhibit condition exists.

3. The method of claim 1, wherein step E includes the steps of:

E1) determining whether the communication resource is available for random access;

E2) upon determining that the communication resource is available for random access, determining whether to request a reserved time slot;

E3) upon determining to request a reserved time slot, transmitting a request for at least one reserved time slot.

4. A method of transmitting a data packet on a shared communication resource, comprising the steps of:

in a communication unit;

A) maintaining a clock;

B) determining that an inhibit condition on the shared communication resource will occur, and then determining when the inhibit condition begins;

C) detecting when the inhibit condition concludes;

D) determining when transmission of a data packet on the shared communication resource by the communication unit is desired;

E) attempting to transmit a data packet on the shared communication resource as a function of;

i) the beginning and concluding times of at least one of the detected inhibit conditions; and

ii) when transmission on the shared communication resource was desired.

5. The method of claim 4, wherein step B includes the steps of:

B1) determining when the communication resource is scheduled for a reserved state;

B2) when the communication resource begins the reserved state, determining that the inhibit condition exists.

6. The method of claim 4, wherein step E includes the steps of:

E1) determining whether the communication resource is available for random access;

E2) upon determining that the communication resource is available for random access, choosing whether to request a reserved time slot, or transmit an unreserved data packet;

E3) upon choosing to request a reserved time slot, transmitting a request for at least one reserved time slot in a random access slot, then

E4) determining whether the communication resource is available for reserved access, then

E5) upon determining that the communication resource is available for reserved access, transmitting the data packet in said at least one reserved time slot;

E6) upon choosing to transmit an unreserved data packet, transmitting the unreserved data packet in the random access slot.

7. A method of accessing a shared communication resource, comprising the steps of:

in a communication unit;

A) maintaining a clock;

B) determining that an inhibit condition on the shared cummunication resource will occur, and then determining when the inhibit condition begins;

C) detecting when the inhibit condition concludes;

D) determining when access to the shared communication resource by the communication unit is desired;

E) when access to the shared communication resource by the communication unit is desired, determining whether a current inhibit conditiion exists;

F) when a current inhibit condition exists, detecting when the current inhibit condition concludes, then

G) attempting to access the shared communication resource as a function of;

i) the beginning and concluding times of at least one of the detected inhibit conditions; and

ii) when access to the shared communication resource was desired;

H) when a current inhibit condition does not exist, determining whether a prior inhibit condition has been detected;

I) when a prior inhibit condition has been detected, attempting to access the shared communication resource as a function of;

i) the beginning and concluding times of at least one of the detected inhibit conditions; and

ii) when access to the shared communication resource was desired;

J) when a prior inhibit condition has not been detected, attempting to access the shared communication resource.

8. A method of accessing a shared communication resource, comprising the steps of:

in a communication unit;

A) maintaining a real time clock and a virtual time clock;

B) determining that an inhibit condition on the shared communication resource will begin, and when the inhibit condition begins, suspending the virtual time clock in response thereto;

C) detecting when the inhibit condition concludes, and resuming operation of the virtual time clock in response thereto;

D) determining a time when access to the shared communication resource by the communication unit is desired;

E) attempting to access the shared communication resource as a function of when the virtual time clock has a predetermined relationship with respect to the time when access to the shared communication resource by the communication unit was desired.

9. The method of claim 8, wherein step C includes the steps of:

C1) resuming operation of the virtual time clock at a rate greater than the real time clock;

and further the step of;

C2) determining when the virtual time clock equals the real time clock, and operating the virtual time clock at a rate equal to the real time clock in response thereto.

10. The method of claim 9, wherein step C1 includes the steps of:

C1a) selecting a virtual time clock rate greater than the real time clock rate;

C1b) operating the virtual time clock at the selected rate.

11. The method of claim 10, wherein step C1a includes the steps of:

in a communication receiver;

C1ai) receiving messages from a plurality of communication units using a shared communication resource;

C1aii) selecting a virtual time clock rate, greater than or equal to the real time clock rate, as a function in part of messages received from the communication units;

C1aiii) indicating the selected virtual time clock rate to the plurality of communication units.

12. The method of claim 8, wherein step C includes the step of:

C1) on a non-periodic basis, receiving a transmission indicating a difference between time values of a virtual time clock and real time clock.

13. The method of claim 8, wherein step C includes the step of:

C1) on a non-periodic basis, receiving time values of a virtual time clock and real time clock.