JP2850682B2 - Satellite communication transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite communication transmission system, and more particularly to a master DAMA controller at a central station, a slave DAMA controller at each remote station, and the assignment of a satellite channel via a transponder of a communication satellite. The present invention relates to a satellite communication transmission system of a request assignment multiple access type to be performed at the time of occurrence.

[0002]

2. Description of the Related Art In this type of conventional satellite communication transmission system, the transmission speed of each satellite channel is fixed.
In response to a call request from a subscriber, an empty satellite channel is given to the call, and the line is connected.

[0003]

As described above, in the conventional request assignment multiple access type satellite communication transmission system, since the transmission speed of each satellite channel is fixed, there are the following problems.

Since the number of usable satellite channels is fixed, the band of the transponder cannot be used effectively. That is, even if the transmission speed of information from the subscriber is slow, the transmission speed of the satellite channel is slowed, and the bandwidth of the satellite channel is narrowed so that many satellite channels can be provided in the transponder bandwidth, Since the number of channels is fixed, the band of the transponder cannot be used effectively. The number of available satellite channels is fixed for the following reason. That is, since the power used by the transponder of the communication satellite generally depends on the transmission speed of the satellite channel in use, the number of available satellite channels is naturally fixed due to the limit of the available power of the transponder.

[0005] Since the transmission rate of information transmitted to each satellite channel is fixed, if the transmission rate of information from the subscriber is lower than the transmission rate of the satellite channel, the usage efficiency of the satellite channel is reduced. Conversely, if it is high, transmission becomes impossible.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a demand assignment multiple access type satellite communication transmission system capable of appropriately changing the transmission speed of a satellite channel. It is in.

[0007]

According to the present invention, there is provided a satellite channel having a master DAMA controller in a central station and a slave DAMA controller in each remote station, and passing through a transponder of a communication satellite. In a request assignment multiple access type satellite communication transmission system in which call assignment is performed when a call is generated, the central station and the remote station are provided with a variable speed modem and a transmission power control device, and the master DAMA controller is adapted to generate a call. When allocating a satellite channel, a command is issued to the variable-rate modem to make the transmission speed of the satellite channel allocated to the call required by the call, and the power of the transponder is used by allocating the satellite channel. If it exceeds the possible range, the variable speed modulation and demodulation An instruction to at least one of the transmitter and the transmission power control device to lower at least one of the transmission speed and the transmission power of the satellite channel so that the power used by the transponder falls within an available range; If the sum of the bandwidths of the used satellite channels exceeds the limit value, an instruction is issued to the variable speed modem to reduce the transmission speed of the satellite channels, and the sum of the bandwidths of the used satellite channels is limited. It does not exceed the value.

Further, the present invention provides a method for improving transmission efficiency when a call is disconnected and there is a margin in the power used by the transponder.
When the power used by the transponder has a margin, an instruction is issued to the variable speed modem to increase the transmission speed of the satellite channel.

[0009]

In the configuration (A), when a call occurs, a satellite channel is allocated. At that time,
Make the transmission rate of the satellite channel to be assigned what the call requires. In addition, if the power used by the transponder exceeds the usable range by allocating the satellite channel, the transmission speed of the satellite channel,
At least one of the transmission powers is reduced so that the power used by the transponder falls within the usable range. If the sum of the used satellite channel bands exceeds the limit value, the transmission speed of the satellite channel is reduced so that the sum of the used satellite channel bands does not exceed the limit value.

In the configuration (B), when a call is disconnected and the power used by the transponder has a margin, the transmission speed of the satellite channel is increased to improve the transmission efficiency.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a satellite communication transmission system of a request assignment multiple access type according to the present invention.
2-1 to 2-n are remote stations, and 3 is a communication satellite.

The central station 1 includes a plurality of variable speed modems (VR MODEMs) 11-1 to 11-m and earth stations provided for each of the variable speed modems 11-1 to 11-m. Transmission power control device (EIRP CONT) 12-1 to 1
2-m, and a master DAMA controller 13 that performs request assignment multiple access control while controlling these.

On the other hand, each of the remote stations 2-1 to 2-n has
Variable speed modems 21-1 to 21-n, earth station transmission power control devices 22-1 to 22-n, and master D of central station 1
Under the control of the AMA controller 13, the local station's variable speed modems 21-1 to 21-n and the earth station transmission power control device 2
Slave DAMA controllers 23-1 to 23-n for performing request assignment multiple access control while controlling 2-1 to 22-n
And are included.

Further, the communication satellite 3 includes a transponder 3
1 is included.

Next, the operation of this embodiment will be described.

When a call from a subscriber is sent from an exchange or the like (not shown), the central office 1 sends the call to the master DAM.
Inform A controller 13.

When a call from a subscriber is added, the master DAMA controller 13, as shown in the flowchart of FIG.
The transmission rate according to the request of the call and the channel number of the satellite channel to be used are set in an available variable-speed modem (for example, the variable-speed modem 11-i), and the earth corresponding to the variable-speed modem 11-i is set. Station transmission power control device 12
-Set the value of earth station transmit power according to the call request to i;
Further, the remote station on the called side (referred to as remote station 2-j)
Of the above transmission speed, channel number, and earth station transmission power to the slave DAMA controller 23-j of
The transmission rate and the channel number are set in the variable speed modem 21-j, and the value of the earth station transmission power is set in the earth station transmission power control device 22-j (step S1).

Thereafter, the master DAMA controller 13
Is the transmission speed, frequency,
The power usage rate α of the transponder 31 is calculated based on the earth station transmission power, the transmission rate and frequency of the channel used by the newly generated call, and the earth station transmission power.
(Step S2).

After calculating the usage rate α, the master DAMA controller 13 determines whether the usage rate α exceeds 100, that is, whether the power usage exceeds the usable power of the transponder 31 (step S3).

If it is determined that the usage rate α exceeds 100, the priority channel is left as it is, and an instruction is given to at least one of the variable speed modem and the earth station transmission power control device corresponding to the movable channel. To lower at least one of the transmission speed and the earth station transmission power,
The usage rate α is set to less than 100 (step S
4).

Thereafter, the master DAMA controller 13
Collects the band characteristics of the satellite channels in use (step S5), and determines whether the sum of the bands of the satellite channels in use exceeds a limit value which can be arbitrarily set in advance.
(Step S6).

If it is determined that the threshold value is exceeded, an instruction is issued to the variable speed modulator / demodulator corresponding to the movable channel to lower the transmission speed so that the sum of the bands does not exceed the limit value (step S7) Then, other processing is performed.

Such processing is performed every time a call is generated from a subscriber of the central office 1.

When a subscriber of the remote station 2-1 to 2-n makes a call, the remote station 2-1 to 2-n becomes the central station 1
Is transferred to the master DAMA controller 13, and the master DAMA controller 13 performs the same processing as described above.

When a call is disconnected, the master D
The AMA controller 13 calculates the power usage rate α of the transponder 31 in the same manner as described above, and if the power of the transponder 31 has a margin, issues an instruction to the variable speed modem corresponding to the movable channel to increase the transmission rate. To improve transmission efficiency.

[0027]

As described above, according to the present invention, when a satellite channel is allocated when a call is generated, the transmission rate of the satellite channel allocated to the call is controlled according to the request of the call.
In addition, since the transmission speed and the transmission power of the satellite channel are controlled based on the sum of the power consumption and the bandwidth used by the transponder, the number of satellite channels is made variable so that the bandwidth of the transponder is effectively used to the maximum. In addition to this, there is an effect that transmission becomes impossible due to the transmission speed of information from the subscriber and that the use efficiency of the satellite channel is not reduced.

Further, according to the present invention, when the power of the transponder has a margin when the call is disconnected, the transmission speed of the satellite channel is increased, so that the transmission efficiency of the satellite channel can be increased. effective.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing example of an embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Central station 2-1 to 2-n ... Remote station 11-1 to 11-m, 21-1 to 21-n ... Variable speed modem 12-1 to 12-m, 22-1 to 22-n ... Earth station transmission power control device 13 Master DAMA controller 23-1 to 23-m Slave DAMA controller 3 Communication satellite 31 Transponder

Continuation of the front page (56) References JP-A-63-283238 (JP, A) JP-A-1-243735 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04B 7 / 14-7/22

Claims (2)

(57) [Claims] 1. A request assignment multiple access type satellite communication transmission comprising a master DAMA controller in a central station, a slave DAMA controller in each remote station, and assignment of a satellite channel via a transponder of a communication satellite when a call is generated. In the method, the central station and the remote station are provided with a variable speed modem and a transmission power control device, and the master DAMA controller issues an instruction to the variable speed modem when allocating a satellite channel when a call occurs. If the transmission rate of the satellite channel to be assigned to the call is required by the call, and if the power used by the transponder exceeds the usable range by allocating the satellite channel, the variable speed modem and the transmission power Give instructions to at least one of the controllers Lowering at least one of the transmission speed and the transmission power of the satellite channel so that the power used by the transponder falls within the usable range, and furthermore, the sum of the bandwidths of the used satellite channels exceeds the limit value. In this case, the transmission of the satellite channel is reduced by issuing an instruction to the variable speed modem to reduce the sum of the bandwidths of the used satellite channels so as not to exceed a limit value. method. 2. The system according to claim 1, wherein the master DAMA controller, when disconnecting the call, issues an instruction to the variable speed modem to increase the transmission speed of the satellite channel if the transponder has sufficient power. Item 2. A satellite communication transmission method according to item 1.