JP2000278234A - Time slot re-assignment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use a channel even in the case of fixed type time division multiple address communication where subscription and retire of stations are frequently conducted like aircrafts. SOLUTION: A retire monitor means 3 monitors a received time slot to monitor a retired station. Furthermore, a subscription monitor means 8 monitors the received time slot to monitor re-subscription of a retired station. A retire management means 4 re-assigns a time slot when a station is retried. Moreover, the subscription means 9 re-assigns a time slot when a retired station makes re-subscription.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time slot reassignment system, and more particularly to a time slot reassignment system in time division multiple access communication for directly communicating between communication devices mounted on an aircraft or the like.

[0002]

2. Description of the Related Art Conventionally, in a time division multiple access (TDMA) communication system, a technique for effectively using a line by using a time slot for synchronization as a time slot for data is disclosed in, for example, Japanese Patent Application Laid-Open No. 05-167488. (“Wireless communication line setting method”).

As shown in FIG. 8, according to this publication, the first and second reference stations transmit a reference station synchronization burst in a synchronization burst time slot of a TDMA frame. On the other hand, the first and second slave stations maintain burst synchronization by transmitting a slave synchronization burst to the satellite link. Here, when setting a satellite link between the first and second slave stations by demand assignment, the satellite link setting processor searches for a data burst time slot that can be used. For example, if the first slave station sends a slave synchronization burst to an F1 transponder (repeater) and the second slave station sends a slave synchronization burst to an F2 transponder (repeater), the time slots other than those at the same time are assumed. The time slot for the synchronous burst and the time slot for the data burst are used as the time slot for the data burst, and are transmitted, for example, via the F5 transponder.

[0004]

However, the conventional technique is applied to communication using a transponder, and is a time-division multiplex system for directly communicating between communication apparatuses mounted on an aircraft or the like. Not applicable to

FIG. 9 is a conceptual diagram of a conventional time division multiple system. As shown in FIG. 9, the aircraft stations A, B, C,
D and E transmit and receive information by omnidirectional communication using fixedly assigned time slots. The problem with this fixed time division multiplex system is that unusable time slots occur when stations frequently join and leave. In fixed time division multiple access communication, a time slot is fixedly assigned to each station. If each station is constantly communicating, the assigned time slot is used effectively. If the user frequently joins and leaves the network, the time slot assigned to the leaving station is not used.

Accordingly, the present invention monitors the use status of a time slot, determines a station that has left, and reassigns a time slot that has been allocated to the departed station to another station, thereby effectively enabling a line. The task is to use it.

[0007]

According to the present invention, there is provided a time slot reassignment system comprising at least two communication stations and a control station for controlling time division multiple access between the communication stations. The control station releases all the time slots allocated to the communication station when the communication station has not used the time slot allocated for a predetermined time or more, and Re-allocation processing for allocating to one of the communication stations.

That is, in the present invention, when the withdrawal monitoring means and the subscription monitoring means monitor the use status of the time slot, and when the withdrawal and re-entry are detected, the withdrawal management means and the subscription management means set the time slot to the time slot. Is reassigned.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a control station in the time slot reallocation system of the present invention. As shown in FIG. 1, the receiving means 1 receives data by fixed time division multiple access communication. The departure monitoring means 3 monitors the time slot received by the receiving means 1, determines the departure of the station, updates the departure information 5, and notifies the departure management means 4. According to the leaving information notified from the leaving management means 4 and the leaving monitoring means 3, time slots are reassigned and control information is transmitted to each station. The transmission means 7 transmits data such as control information of the leave management means 4 and the subscription management means 9 by fixed time division multiple access communication. The leaving information 5 records information on the station that has left. The time slot allocation table 6 records the time slot allocation at the time of default and after the reallocation. The joining monitoring means 8 monitors time slots assigned to stations other than the default station, determines rejoining of the leaving station, updates the leaving information 5 and notifies the joining managing means 9. The subscription management unit 9 reallocates the time slot according to the resubscription information notified from the subscription monitoring unit 8, and transmits control information and time for data retransmission to each station.

Specifically, the departure monitoring means 3 monitors the departure of the station based on the time slot received by the receiving means 1. Monitoring of station departure is performed by determining the time difference between the time when each station last used the time slot and the current time. That is, when it detects the use of a timeslot,
The time slot use time of the time slot use station in the time slot use time storage means 2 is changed to the time slot use time.

FIG. 2 is a table showing a specific example of the time slot use time stored in the time slot use time storage means 2. As shown in FIG. 2, the latest time slot use time of all stations is recorded in this table as the time slot use time.

Further, the departure monitoring means 3 calculates the time difference between the time slot use time of each station recorded in the time slot use time storage means 2 at a fixed interval and the current time, and leaves the station whose time difference has become a predetermined time or more. It is determined that it has been performed.

When it is determined that the station has left, the leaving monitoring means 3 records the information of the leaving station in the leaving information 5 and notifies the leaving management means 4 of the information of the leaving station. The leaving information 5 records information of all the stations determined to have left.

The leaving management means 4 reassigns the time slots based on the information of the time slot allocation table 6 in accordance with the notification of the leaving station from the leaving monitoring means 3 and notifies each station.

FIG. 3 shows a specific example of the time slot assignment table 6. As shown in FIG. 3, a default (initial) assigned station and an assigned station after re-assignment are recorded for all time slots used in the time division multiple access communication system.

The leaving management means 4 reallocates the time slots by allocating the time slots allocated to the leaving station to other stations.

FIG. 4 shows an example of reallocation. In the example shown in FIG. 4, the name of one station is made to correspond to each time slot number in ascending order from the left of the array, and the station names are stored in consideration of the priority and / or at random.

When a certain station leaves, the leaving management means 4
Refers to the time slot allocation table 6 to check the number of time slots allocated to the station that has left, and allocates time slots to other stations by the number of time slots.

When the reassignment of all the time slots assigned to the departed station is completed, the departure management means 4
Updates the assigned station in the time slot assignment table 6 after the reassignment, and transmits information for controlling the reassignment to the new assigned station via the transmitting means 7.

FIG. 5 is a configuration diagram of a frame used in the time slot reallocation system of the present invention. As shown in FIG. 5, information for reallocation control is transmitted using a control time slot. The information for controlling the reallocation includes, for example, the target station of the reallocation, the number of the time slot to be reallocated, and the like.

The joining monitoring means 8 monitors the rejoining of the leaving station. The re-joining of the leaving station is monitored by referring to the time slot assignment table 6 and monitoring the time slot numbers where the default assignment station and the assignment station after the re-assignment are different.

When a station that has left uses a time slot again, interference of the time slot occurs if the time slot is used by another station.

On the other hand, when the station that has left uses the time slot again, if the time slot is not used, no time slot interference occurs. However, the station that has left once is different from the assigned station after the reassignment in the time slot assignment table 6, and thus such a mismatch cannot be neglected.

Therefore, upon detecting the interference of the time slot or the mismatch between the assigned station and the using station, the joining monitoring means 8 judges that re-joining is desired, and uses the information of the re-joined station from the leaving information 5. At the same time, the information and the time of the station that has re-joined are notified to the joining management means 9.

The subscription management means 9 changes the reassignment of the time slot based on the information of the time slot assignment table 6 according to the notification of the rejoined station from the subscription monitoring means 8, and notifies each station. The change of the reassignment of the time slot is performed in the same manner as the reassignment of the time slot of the withdrawal management means 4 to perform the reassignment when the stations recorded in the withdrawal information 5 sequentially leave from the default time slot assignment.

When the time slot reassignment is completed, the subscription management means 9 updates the assigned station after the reassignment in the time slot assignment table 6 and transmits the information for controlling the reassignment to the station to be reassigned. In addition, information on the rejoining time and the retransmission target station is transmitted via the transmission means 7.

FIG. 6 is a block diagram of a leaving station or a rejoining station in the time slot reassignment system of the present invention. The control information processing unit 33 performs a process according to the information of the control time slot among the time slots received by the receiving unit 11. Specifically, the information of the time slot allocation 22 is updated according to the information for controlling the reallocation, and the transmission data retransmitting means 55 is notified of the rejoin time.

FIG. 7 is a table showing the time slot allocation stored in the time slot allocation means 22. As shown in FIG. 7, this table records the default assigned time slot of the own station and the assigned time slot after the reallocation.
When the station is started, the assigned time slot after the reassignment is returned to the default assigned time slot.

The transmission data retransmitting means 55, when notified of the rejoining time from the control information processing means 33, transmits the information stored in the transmission data accumulating means 66 between the leaving time and the time when the rejoining time is received. Resend transmission data. The transmitting means 44 transmits data in the time division multiple access communication system using the allocated time slots after the reallocation by the time slot allocating means 22. The transmission data storage unit 66 stores the data transmitted by the transmission unit 44 for a certain period of time.
Accumulate temporarily.

[0031]

According to the present invention described above, a time slot fixedly allocated to a station that has left is re-allocated to another station, so that a station can frequently join and leave such as an aircraft. Even in the fixed time division multiple access communication performed, the line can be used effectively.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control station in a time slot reallocation system of the present invention.

FIG. 2 is a specific example of a time slot use timetable.

FIG. 3 is a specific example of a time slot assignment table.

FIG. 4 is an array diagram showing an example of reallocation

FIG. 5 is a configuration diagram of a frame used in the time slot reallocation system of the present invention.

FIG. 6 is a block diagram of a communication station in the time slot reallocation system of the present invention.

FIG. 7 is a specific example of a time slot assignment table.

FIG. 8 is a block diagram of a conventional wireless communication line setting method.

FIG. 9 is a block diagram of a time division multiple access communication system that directly communicates air-to-air.

[Explanation of symbols]

 Reference Signs List 1 receiving means 2 time slot use time 3 leaving monitoring means 4 leaving managing means 5 leaving information 6 time slot allocation table 7 transmitting means 8 joining monitoring means 9 joining managing means 11 receiving means 22 time slot assigning means 33 control information processing means 44 sending Means 55 Transmission data retransmission means 66 Transmission data storage means

Claims (6)

[Claims] 1. A time slot reassignment system comprising two or more communication stations and a control station for controlling a time division multiple access between the communication stations, wherein the control station is configured such that the communication station has a predetermined time or more. When the time slots allocated to the communication station are not used, all the time slots allocated to the communication station are released, and re-allocation to another one communication station is performed. Time slot reassignment system. 2. The another communication station according to claim 1,
2. The time slot reassignment system according to claim 1, wherein the time slot reassignment is determined based on a predetermined priority. 3. The control station includes a time slot use time storage unit, and stores a use time using a time slot for each of the communication stations, wherein a difference between the use time and a current time is equal to or longer than a predetermined time. 2. The method according to claim 1, wherein the reallocation is performed when
A time slot reassignment system as described. 4. The time slot allocation table, wherein the control station has a time slot allocation table, and stores, for each time slot number, a communication station identification number initially allocated and a communication station number after the reallocation. 2. The method according to claim 1, wherein when there is a transmission from an unallocated communication station that is not stored as the communication station number after the reallocation, the reallocation is performed for the non-allocated communication station. Time slot reassignment system. 5. The communication station comprises time slot allocating means, wherein one or two or more time slot numbers initially allocated and one or more time slot numbers re-allocated from the control station are received. The time slot reassignment system according to claim 1, wherein? 6. The communication station comprises: a transmission data storage unit;
Transmission data retransmission means, data between the release time and the subsequent reassignment time is stored as retransmission data in the transmission data storage means, and based on the notification of the next reassignment time, the retransmission data 2. The time slot reassignment system according to claim 1, wherein the transmission data is transmitted from the transmission data retransmission unit.