JPH02312416A - Synchronizing establishing method for tdma system - Google Patents

Abstract

PURPOSE:To firmly establish the transmission synchronism of a remote station at a low cost without a person's help by measuring the distance information of the remote station by using a test channel by a district center, and transmitting its correcting information to the remote station. CONSTITUTION:The district center instructs an offset timing 21 of default to a remote station so that transmitting data from the remote station can be received in a position of 20. In the case this value is correct, communication between the district center and the remote station becomes a timing shown by a full line, and by transmitting the data in a position of 22 from the remote station, the data is received in a position of 20 in the district center. However, usually the communication timing generates such a dislocation as shown by a broken line due to a difference of a satellite delay caused by a geographical position of the remote station. Therefore, in the acquisition of an actual operation channel, the district center corrects a transmission timing offset of the remote station from that which is shown by 21 to that which is shown by 26, by which the transmitting data from the remote station is launched in a position of 27 and can be received at a position of 20 expected by the district center.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is applied to satellite networks. The present invention is TDM
This invention relates to a method for establishing transmission synchronization of remote stations in a star-shaped satellite network using the A (time division multiple access) method.

〔overview〕

The present invention is a method for establishing synchronization in a TDMA system consisting of one central station and a plurality of remote stations, in which the central station measures distance information of the remote stations using a test channel, and transmits correction information to the remote stations. By setting this value in the remote station, transmission synchronization of the remote station can be established without human intervention and without interfering with other signals.

[Conventional technology]

Conventionally, in a centralized network using the TDMA method consisting of a large-scale central station and many small-scale remote stations,
Transmission from a central station to a remote station (Outbo-und) is possible when each remote station extracts the signal addressed to itself from among the continuous signals transmitted by the central station. Transmission to (Inb-ound) requires synchronization control in accordance with the geographical location of each remote station so that the burst signals output from each remote station fit into a predetermined time slot.

In a high-speed, large-scale TDMA network for this type of synchronization control, the reference station establishes synchronization of slave stations using the channel that other slave stations are operating, so other slave stations are not affected. It is necessary to establish highly accurate synchronization, and in the low-speed TDMA system, it is necessary for each remote station to set information for synchronization control, and thereby establish transmission synchronization by the remote station itself.

[Problem that the invention seeks to solve]

In the conventional technology described above, the control of establishing transmission synchronization of slave stations by the reference station used in the large-scale TDMA system requires high accuracy in order to establish transmission synchronization of slave stations without causing problems to other slave stations in operation. A high degree of control is required, and both the reference station and slave station require various functions and additional equipment, leading to an increase in the scale and cost of the equipment. Therefore, in the low-speed TDMA system, as mentioned above, a method is used in which information for synchronization control is set in advance at each remote station, but in this case, the person who initially starts up the remote station must make this setting. Moreover, in order to omit this setting when restarting the system when it goes down, it is necessary to maintain synchronization information by hardware, which increases the cost of the device. Furthermore, if the remote station moves frequently, it is necessary to reset the synchronization information each time.

The present invention solves these problems, and aims to establish synchronization of transmission between remote stations in a star network satellite communication using the TDMA method using a simple method without using acquisition. .

[Means for solving problems]

The present invention provides a method for establishing synchronization in a TDMA system using a satellite and consisting of one central station that generates synchronization timing and a large number of remote stations that cannot obtain synchronization timing on their own, in which the central station is remote. The method is characterized in that distance information to the station is measured using a test channel, this distance information is transmitted to the remote station, and the remote station sets a default value obtained from this distance information.

The present invention also includes one central station and a plurality of remote stations that cannot acquire synchronized timing on their own,
The central station includes synchronization timing generation means for generating synchronization timing, and synchronization control means for measuring the synchronization state of the remote station and generating a synchronization correction value, and the remote station receives data received from the central station. data detection means for extracting frequency control information for determining a transmission channel and offset timing information for determining transmission timing; and transmission control means for controlling data transmission to the central station. In the TDMA synchronization establishment method, a default value of offset timing that determines the transmission channel and transmission timing of the remote station is added to the central station, and acquisition data necessary for the remote station to establish transmission synchronization is provided. The data detection means of the remote station includes data creation means for creating and transmitting data to the remote station from a test channel, and timing detection means for detecting the timing of receiving a signal on the test channel from the remote station, and the data detection means of the remote station includes It may include means for detecting a default value and setting this default value in the transmission control means.

[Effect]

The central station measures the distance to the remote station using a test channel, communicates this distance information to the remote station, and the remote station sets a default value derived from this distance information.

This makes it possible to establish transmission synchronization between remote stations without any human intervention and at a low cost.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration on the central station side of an embodiment of the invention, and FIG. 2 is a block diagram showing the configuration on the remote station side of the embodiment of the invention.

The embodiment of the present invention includes one central station and a plurality of remote stations that cannot obtain synchronized timing on their own, and the central station includes:
synchronous timing generation means for generating synchronous timing;
The remote station includes a demodulator 11 and information for frequency control that determines a transmission channel from data received from the central station. a data detector 8 for extracting offset timing information necessary to determine transmission timing;
It is equipped with a transmission control unit 9 for controlling data transmission to the central station and a modulator 10, and further includes a default value of offset timing for determining the transmission channel and transmission timing of the remote station in the central station. A data generator 1 that creates acquisition data necessary for the remote station to synchronize transmission and transmits it to the remote station from a test channel; and a timing detector 2 that detects the timing of receiving a signal on the test channel from the remote station. a test channel including a modulator 5 and a demodulator 6 connected to the test channel,
It is equipped with an operational channel including a data generator 3 and a data detector 4, and a demodulator 7 connected to this operational channel, and furthermore, a data detector 8 of a remote station detects a default value and a transmission controller 9 includes a means for setting this default value.

Next, the operation of the embodiment of the present invention configured as described above will be explained. First, the data generator 1 of the central station creates acquisition data necessary for remote stations to synchronize transmission. Added to this data is a default offset timing value that determines the remote station's transmission channel and transmission timing. This data is communicated to the remote station via modulator 5.

At the remote station, after passing through a demodulator 11, a data detector 8 extracts frequency control information for determining a transmission channel and offset timing information for determining a transmission timing from the received data. It is passed to the control section 9. Through this control, the remote station transmits test data to the test channel at a timing according to instructions from the central station.

After data from the remote station passes through a test demodulator 6 at the central station, a timing detector 2 detects the reception timing actually received by the central station. At this time, if the default offset timing is appropriate, the received data will be received at the timing instructed by the central station, but in reality, timing deviations occur due to differences in satellite delays and other factors depending on the geographical location of each remote station.

Next, acquisition on the operational system is performed in the same manner as above, but at this time, the remote station's transmission channel data added to the acquisition data is changed to the operational channel, and the value of the transmission offset timing is changed to the default offset value. In contrast, by using corrected offset timing that takes into account the reception timing shift obtained in the test system, it is possible to notify the remote station of appropriate transmission timing information.

FIG. 3 shows the above procedure along the time axis. The central station has a default offset timing of 21 so that it can receive transmitted data from the remote station at a position of 20.
to the remote station. If this value is appropriate, communication between the central station and the remote station will occur at the timing shown by the solid line, and the remote station will transmit data at position 22, and the central station will receive the data at position 20.

However, the communication timing usually deviates as shown by the broken line due to differences in satellite delay depending on the geographical location of the remote station. In this case, at the remote station, the offset timing shifts from position 21 to position 23, and the transmission data is placed at position 24. Therefore, in the central station, the received data is received at position 25 instead of position 20.

Therefore, in the acquisition of the actual operational channel, the central station corrects the transmission timing offset of the remote station from 21 to 26, so that the transmission data from the remote station is launched at position 27, and the central station This means that it can be received at 20 expected positions.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and can include various modifications to its components and shapes within the scope of the gist.

〔Effect of the invention〕

As explained above, according to the present invention, the central station measures the distance information of the remote station using a test channel, and transmits the correction information to the remote station, thereby manually establishing transmission synchronization of the remote station. This has the effect of being able to provide it at a low price without any intervention.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the central station in an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a remote station according to an embodiment of the present invention. FIG. 3 is an explanatory diagram showing the communication timing between the central station and remote stations according to the embodiment of the present invention. 1.3...Data generator, 2...Timing detector, 4, Death...Data detector, 5.10...Modulator, 6
．． 7.11... Demodulator, 9... Transmission control unit.

Claims (1)

[Claims] 1. A method for establishing synchronization in a TDMA system using a satellite and consisting of one central station that generates synchronization timing and a large number of remote stations that cannot obtain synchronization timing on their own, comprising: A TDMA method characterized in that a central station measures distance information with a remote station using a test channel, transmits this distance information to the remote station, and sets a default value obtained from this distance information at the remote station. How to establish synchronization.