Communication control method and communication control apparatus

• US 6,603,747 B2
• Filed: 11/13/1998
• Issued: 08/05/2003
• Est. Priority Date: 11/14/1997
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Asai, Akio
• Primary Examiner(s): Jung, Min
• Application Number:
  US09/190,204
• Publication Number:
  US 20030058817A1
• Time in Patent Office: 1,726 Days
• Field of Search: 370/316, 370/319, 370/321, 370/322, 370/329, 370/442, 370/443, 370/444, 370/462, 370/336, 370/447
• US Class Current: 370/322
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04B 7/212 Time-division multiple access [TDMA]

Abstract

A priority corresponding to the emergency level of a communication in each slave station is allocated to a time slot assignment request transmitted from each slave station to master station. When master station receives the time slot assignment request to which the priority is set, the priority of the time slot assignment request is judges in slot assignment controller. When there is not any vacant time slot having the priority judged and at the same time there is a vacant time slot whose priority is lower than the priority concerned, the time slot whose priority is lower than the priority concerned is allocated to the time slot assignment request, whereby the assignment waiting time until data having a high emergency level are transmitted can be shortened.

Claims

1. A communication control method in which plural slave stations transmit data to a master station through a transmission channel of a time division multiple access system, said master station transmits data to said slave stations in a broadcast mode, said master station assigns a time slot to a time slot assignment request transmitted from each of said slave stations to said master station, and each of said slave stations performs the communication by using the time slot assigned thereto, the method comprising:

an initial priority level assigning step for securing time slots for each priority level, said initial priority level assigning step being executed by said master station;

a priority level assigning step for assigning, in accordance with the emergency level of a communication, a priority level to a time slot assignment request to be transmitted from each of said slave stations to said master station, said priority level assigning step being executed by each of said slave stations;

a priority level judging step for judging the priority level assigned to the time slot assignment request when said master station receives the time slot assignment request to which the priority level is assigned in said priority level assigning steps, said priority level judging step being executed by said master station;

a time slot assigning step for assigning to the time slot assignment request a time slot having the same priority level as the time slot assignment request when there is at least one time slot having the same priority level as the time slot assignment request, and alternatively assigning to the time slot assignment request a time slot having a priority level which is lower than the priority level of the time slot assignment request when there is no time slot having the same priority level as the time slot assignment request, and there is at least one time slot having a priority level which is lower than the priority level of the time slot assignment request, said time slot assigning step being executed by said master station;

an assignment request accumulating step for accumulating time slot assignment request in a queue if there is at least one time slot assignment request accumulated in a queue for every priority level, said assignment request accumulating step being executed by said master station; and

a time slot number changing step for increasing the number of time slots having a given priority level when the number of accumulated time slot assignment requests of that priority level exceeds a predetermined number, while decreasing the number of time slots having the other priorities in compensation for the increase, said time slot number increasing step being executed by said master station,

wherein said time slot assignment step is executed for a new time slot assignment request if there is no past time slot assignment request which has been accumulated in a queue for every priority level, and

wherein accumulation of a time slot assignment request in the queue is executed if the time slot having the same priority level as the time slot assignment request is occupied and the time slot having a priority level which is lower than the priority level of the time slot assignment request is also occupied in said time slot assignment step.

2. A communication control method in which plural slave stations transmit data to a master station through a transmission channel of a time division multiple access system, said master station transmits data to said slave stations in a broadcast mode, said master station assigns a time slot to a time slot assignment request transmitted from each of said slave stations to said master station, and each of said slave stations performs the communication by using the time slot assigned thereto, the method comprising:

an initial priority level assigning step for securing time slots for each priority level, said initial priority level assigning step being executed by said master station;

a priority level assigning step for assigning, in accordance with the emergency level of a communication, a priority level to a time slot assignment request to be transmitted from each of said slave stations to said master station, said priority level assigning step being executed by each of said slave stations;

a priority level judging step for judging the priority level assigned to the time slot assignment request when said master station receives the time slot assignment request to which the priority level is assigned in said priority level assigning step, said priority level judging step being executed by said master station;

a time slot assigning step for assigning to the time slot assignment request a time slot having the same priority level as the time slot assignment request when there is at least one time slot having the same priority level as the time slot assignment request, and alternatively assigning to the time slot assignment request a time slot having a priority level which is lower than the priority level of the time slot assignment request when there is no time slot having the same priority level as the time slot assignment request, and there is at least one time slot having a priority level which is lower than the priority level of the time slot assignment request, said time slot assigning step being executed by said master station;

an assignment request frequency counting step for counting the number of time slot assignment requests within a predetermined time for every priority level, said assignment request frequency counting step being executed by said master station; and

a time slot number changing step for changing the number of time slots for every priority level on the basis of the number of time slot assignment requests within the predetermined time for every priority level wherein the number of time slots for a priority level is increased while the number of time slots for another priority level is decreased in compensation for the increase, said time slot number changing step being executed by said master station.

3. The communication control method as set forth in claim 2, which further comprises:

an assignment request accumulating step for accumulating a time slot assignment request in a queue if there is at least a time slot assignment request accumulated in a queue for every priority level, said assignment request accumulating step being executed by said master station; and

a time slot number changing step for increasing the number of time slots having a priority level of which the number of accumulated time slot assignment requests exceeds a predetermined number, while decreasing the number of time slots having the other priorities in compensation for the increase, said time slot number increasing step being executed by said master station, wherein said time slot assignment step is executed for a new time slot assignment request if there is no past time slot assignment request which has been accumulated in a queue for every priority level, and wherein accumulation of a time slot assignment request in the queue is executed if the time slot having the same priority level as the time slot assignment request is occupied and the time slot having a priority level which is lower than the priority level of the time slot assignment request is also occupied in said time slot assignment step.

4. A communication control method in which plural slave stations transmit data to a master station through a transmission channel of a time division multiple access system, said master station transmits data to said slave stations in a broadcast mode, said master station assigns a time slot to a time slot assignment request transmitted from each of said slave stations to said master station, and each of said slave stations performs the communication by using the time slot assigned thereto, the method comprising:

an initial priority level assigning step for securing time slots for each priority level, said initial priority level assigning step being executed by said master station;

a priority level assigning step for assigning, in accordance with the emergency level of a communication, a priority level to a time slot assignment request to be transmitted from each of said slave stations to said master station, said priority level assigning step being executed by each of said slave stations;

a priority level judging step for judging the priority level assigned to the time slot assignment request when said master station receives the time slot assignment request to which the priority level is assigned in said priority level assigning step, said priority level judging step being executed by said master station;

a time slot assigning step for assigning to the time slot assignment request a time slot having the same priority level as the time slot assignment request when there is at least one time slot having the same priority level as the time slot assignment request, and alternatively assigning to the time slot assignment request a time slot having a priority level which is lower than the priority level of the time slot assignment request when there is no time slot having the same priority level as the time slot assignment request, and there is at least one time slot having a priority level which is lower than the priority level of the time slot assignment request, said time slot assigning step being executed by said master station;

an assignment request number counting step for counting the number of time slot assignment requests for every priority level until the total of the numbers reaches a predetermined value, said assignment request number counting step being executed by said master station; and

a time slot number changing step for changing time slots for every priority level when any of the numbers exceeds a corresponding reference value, wherein the number of time slots for a priority level is increased while the number of time slots for another priority level is decreased in compensation for the increase, said time slot number changing step being executed by said master station.

5. The communication control method as set forth in claim 4, which further comprises:

an assignment request accumulating step for accumulating a time slot assignment request in a queue if there is at least a time slot assignment request accumulated in a queue for every priority level, said assignment request accumulating step being executed by said master station; and

a time slot number changing step for increasing the number of time slots having a priority level of which the number of accumulated time slot assignment requests exceeds a predetermined number, while decreasing the number of time slots having the other priorities in compensation for the increase, said time slot number increasing step being executed by said master station,

wherein said time slot assignment step is executed for a new time slot assignment request if there is no past time slot assignment request which has been accumulated in a queue for every priority level, and

wherein accumulation of a time slot assignment request in the queue is executed if the time slot having the same priority level as the time slot assignment request is occupied and the time slot having a priority level which is lower than the priority level of the time slot assignment request is also occupied in said time slot assignment step.

6. A communication control method in which plural slave stations transmit data to a master station through a transmission channel of a time division multiple access system, said master station transmits data to said slave stations in a broadcast mode, said master station assigns a time slot to a time slot assignment request transmitted from each of said slave stations to said master station, and each of said slave stations performs the communication by using the time slot assigned thereto, the method comprising:

an initial priority level assigning step for securing time slots for each priority level, said initial priority level assigning step being executed by said master station;

a priority level assigning step for assigning, in accordance with the emergency level of a communication, a priority level to a time slot assignment request to be transmitted from each of said slave stations to said master station, said priority level assigning step being executed by each of said slave stations;

a priority level judging step for judging the priority level assigned to the time slot assignment request when said master station receives the time slot assignment request to which the priority level is assigned in said priority level assigning step, said priority level judging step being executed by said master station;

a time slot assigning step for assigning to the time slot assignment request a time slot having the same priority level as the time slot assignment request when there is at least one time slot having the same priority level as the time slot assignment request, and alternatively assigning to the time slot assignment request a time slot having a priority level which is lower than the priority level of the time slot assignment request when there is no time slot having the same priority level as the time slot assignment request, and there is at least one time slot having a priority level which is lower than the priority level of the time slot assignment request, said time slot assigning step being executed by said master station;

an assignment request number counting step for counting the number of time slot assignment requests for every priority level until the total of the numbers reaches a predetermined value, said assignment request number counting step being executed by said master station; and

a time slot ratio changing step for changing the ratio of the number of time slots of each priority level when the difference between the ratio of the number of time slot assignment requests of each priority level and the ratio of the number of time slots of each priority level exceeds a predetermined value, wherein the number of time slots for a priority level is increased while a number of the number of time slots for another priority level is decreased in compensation for the increase, said time slot ratio changing step being executed by said master station.

7. The communication control method as set forth in claim 6, which further comprises:

an assignment request accumulating step for accumulating a time slot assignment request in a queue if there is at least a time slot assignment request accumulated in a queue for every priority level, said assignment request accumulating step being executed by said master station; and

a time slot number changing step for increasing the number of time slots having a priority level of which the number of accumulated time slot assignment requests exceeds a predetermined number, while decreasing the number of time slots having the other priorities in compensation for the increase, said time slot number increasing step being executed by said master station,

wherein said time slot assignment step is executed for a new time slots assignment request if there is no past time slot assignment request which has been accumulated in a queue for every priority level, and

wherein accumulation of a time slot assignment request in the queue is executed if the time slot having the same priority level as the time slot assignment request is occupied and the time slot having a priority level which is lower than the priority level of the time slot assignment request is also occupied in said time slot assignment step.

8. A communication control apparatus in which plural slave stations transmit data to a master station through a transmission channel of a time division multiple access system, said master station transmits data to said slave stations in a broadcast mode, said master station assigns a time slot to a time slot assignment request transmitted from each of said slave stations to said master station, and each of said slave stations performs the communication by using the time slot assigned thereto, wherein said master station comprises:

a judgment unit for judging a priority level extracted from a time slot assignment request whose priority level is set in accordance with an emergency level of a communication and which is transmitted from each of said slave stations;

a slot assignment controller for securing time slots for each priority level, and assigning to the time slot assignment request a time slot having the same priority level as the priority level of the time slot assignment request when there is at least a time slot having the same priority level as the priority level of the time slot assignment request, and alternatively assigning to the time slot assignment request a time slot having a priority level which is lower than the priority level of the time slot assignment request when there is not any time slot having the same priority level as the priority level of the time slot assignment request and there is at least a time slot having a priority level which is lower than the priority level of the time slot assignment request; and

a queue processor for accumulating time slot assignment requests waiting for assignment for every priority level,

wherein said slot assignment controller increases the number of time slots having a priority level of which the number of accumulated time slot assignment requests waiting for assignment exceeds a predetermined number in said queue processor, while decreasing the number of time slot having the other priorities in compensation for the increase, and

wherein on the basis of the priority level of the time slot assignment request, said slot assignment controller assigns to a new time slot assignment request having a priority level lower than the priority level of the new time slot assignment request when any past time slot assignment request having the priority level of the new time slot assignment request is not accumulated in said queue processor and there is not any vacant time slot having the priority level of the new time slot assignment request while there is a vacant time slot whose priority level is lower than the priority level of the new time slot assignment request.

9. A communication control apparatus in which plural slave stations transmit data to a master station through a transmission channel of a time division multiple access system, said master station transmits data to said slave stations in a broadcast mode, said master station assigns a time slot to a time slot assignment request transmitted from each of said slave stations to said master station, and each of said slave stations performs the communication by using the time slot assigned thereto, wherein said master station comprises:

a judgment unit for judging a priority level extracted from a time slot assignment request whose priority level is set in accordance with an emergency level of a communication and which is transmitted from each of said slave stations; and

a slot assignment controller for securing time slots for each priority level, and assigning to the time slot assignment request a time slot having the same priority level as the priority level of the time slot assignment request when there is at least a time slot having the same priority level as the priority level of the time slot assignment request, and alternatively assigning to the time slot assignment request a time slot having a priority level which is lower than the priority level of the time slot assignment request when there is not any time slot having the same priority level as the priority level of the time slot assignment request and there is at least a time slot having a priority level which is lower than the priority level of the time slot assignment request;

wherein said master station further comprises a statistical processor for counting time slot assignment requests within a predetermined time for every priority level which is set in the time slot assignment request transmitted from each of said slave stations to said master station, and said slot assignment controller changes the number of time slots for each priority level on the basis of the number of time slot assignment requests of each priority level which is counted in said statistical processor.

10. The communication control apparatus as set forth in claim 9, which further comprises a queue processor for accumulating time slot assignment requests waiting for assignment for every priority level,

wherein said slot assignment controller increases the number of time slots having a priority level of which the number of accumulated time slot assignment requests waiting for assignment exceeds a predetermined number in said, queue processor, and decreases the number of time slots having the other priorities in compensation for the increase, and

wherein on the basis of the judged priority level, said slot assignment controller assigns to a new time slot assignment request a time slot having a priority level lower than the priority level of the new time slot assignment request when any past time slot assignment request having the priority level of the new time slot assignment request is not accumulated in said queue processor and there is not any vacant time slot having the priority level of the new time slot assignment request while there is a vacant time slot whose priority level is lower than the priority level of the new time slot assignment request.