JP3185868B2 - Diversity control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity control apparatus suitable for use in site diversity communication for exchanging time division information.

[0002]

2. Description of the Related Art In performing various data communications by connecting a terrestrial high-speed communication network and a satellite communication network, when a ground station side has a site diversity configuration, there is a problem that data is duplicated or lost due to bad weather or the like. May occur.

The term "diversity" refers to a method of simultaneously receiving each of signals transmitted through a plurality of communication paths and selecting a signal having the best reception state among them, such as spatial diversity or polarization diversity. And so on. Site (location) diversity is, for example, 1
The communication is performed simultaneously between the base mobile station and a plurality of fixed stations installed in places isolated from each other, and a communication path having the best communication state is selected.

[0004]

As described above, the problem that occurs in site diversity is that when data is transmitted from a terrestrial communication network to two terrestrial stations that make up site diversity, there is a difference in the amount of transmission delay between each other. This is due to the fact that the two stations have independent transmission synchronization timings when performing satellite communication.

[0005] The present invention has been made under such a background, and an object of the present invention is to provide a diversity control apparatus which does not cause loss of information, collision or the like even in time-division information exchange.

[0006]

[Means for Solving the Problems]Claim 1 of the present invention
The gist of the invention described above is that each frame has its own frame with the satellite station.
Exchanges information divided into multiple frames given values
A plurality of earth stations (1, 2) and the plurality of earth stations (1,
Of 2), select the earth station with the best communication status with the satellite station.
And diversity control means (3) for selecting
The evacuity control means (3) receives the plurality of received frames.
Arranging means for rearranging frames in the order of the unique frame values
(35) for communication between the satellite station and the earth station (1, 2)
Performs the TDMA method, and also connects to the earth station (1, 2) and the ground
The communication between the data transmitter and receiver is changed to the data format.
Communication that performs communication in units of frames that do not have frame values
Earth Stations with Site Diversity (1, 2)
The earth station (1) as the active earth station (1)
In the case where the ball station (2) is set as the spare earth station (2)
From the working earth station (1) to the spare earth station
Switching occurs in (2) The working side earth station
Both (1) and the standby earth station (2) receive from the satellite station.
From which frame position of the transmitting TDMA frame
Replace or replace with a new working earth station (2)
From any frame position of the transmitted TDMA frame
Control whether or not to sendCharacterized byDie
It exists in the vacuum controller.Also,Claim 2 of the present invention
The gist of the invention described in (1) is that the plurality of earth stations (1, 2)
Counts the number of each received frame andUnique
Frame value ofFrame counting means (15) for determining
Characterized by havingThe diversity according to claim 1.
In the control unit.Also,Claim 3 of the present invention
The gist of the invention is that the diversity control means (3)Is
The timing of the frame to be transmittedThe plurality of earth stations
(1,2)Transmission synchronization control means (36) for instructing
Characterized byDiversity system according to claim 2
In the control device.Also,The invention according to claim 4 of the present invention.
The gist of the invention is that the transmission synchronization control means (36)Send
Counting the number of the framesUnique frame valueTo
A first transmission frame counting means (38) for determining
Characterized byThe diversity control device according to claim 3.
Exist.Also,The invention according to claim 5 of the present invention
The gist is that the plurality of earth stations (1, 2)Is the frame
Counting the number ofUnique frame valueFrame
Second transmission frame for transmission at a predetermined timing
Characterized by having counting means (16)Claim 4
In the described diversity control apparatus.Also,The invention
The gist of the invention described in claim 6 is that the transmission synchronization control means
Step (36)IsThe first transmission frame counting means (3
8)Counting results andThe second transmission frame counting means (1
6)Holding means for holding each of the differences from the result of
(37) is characterized by havingThe method according to claim 5.
In the ivacity control device.Also,Claims of the invention
The gist of the invention described in 7 is that the transmission synchronization control means (3
6)IsThe plurality of earth stations (1, 2)Selection switching
Switching control means (31) for performingThe first transmission frame
Team counting means (38)Counting results andThe second transmission Shinfure
Team counting means (16)With the result ofThe first based on the difference
Transmission frame counting means (38) and the second transmission frame
Update the offset value of the frame counting means (16)thing
Characterized byThe diversity control device according to claim 6
Exist.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a diversity control device according to an embodiment of the present invention, and is a block diagram illustrating a basic overall configuration of the present invention. This figure 1
And 1 and 2 are TDMA (Time Division Mu
ltiple Access: time division multiple access)
3 is a site diversity control device.

[0008] These earth stations 1, is formed with the site diversity by the earth station 2 and the site diversity control unit 3, also the site diversity control unit 3
Is connected to a ground ATM (Asynchronous Transfer Mode) network 4.

FIG. 2 is a block diagram showing a detailed internal configuration of the earth station 1. As shown in FIG. Since the internal configuration of the earth station 2 is the same as that of the earth station 1, illustration and description are omitted. As shown in FIG. 2, the earth station 1 is an RF (Radio Frequency) unit 1 as an earth station of the TDMA satellite communication system.
2. MODEM (Modulator / Demodulator)
It has a unit 13 and a TDMA control unit 14. Further, the TDMA control unit 14 includes a reception frame synchronization counter 15
And a transmission frame synchronization counter 16.

The earth station 1 has an ATM communication unit 17 as a communication interface with the site diversity control device 3 and an earth station control unit 11 for performing station control including diversity switching.

FIG. 3 is a block diagram showing a detailed internal configuration of the site diversity control device 3. As shown in FIG. In FIG. 3, reference numeral 31 denotes a switching control unit for judging and controlling switching of site diversity, and 32 denotes a terrestrial ATM.
An ATM communication unit which is an interface unit with the network 4 .
33-1 and 33-2 are earth station 1 or earth station 2, respectively.
An ATM communication unit which is a communication interface unit with the ATM.

Reference numeral 35 denotes a frame aligner for absorbing a propagation delay of data from the earth station 1 or 2 (generally, transmission of information from a satellite station to a ground station is referred to as downlink); Is a transmission synchronization control unit for performing transmission timing control at the time of diversity switching for uplink data to the earth station 1 or the earth station 2 (generally, information transmission from the ground station to the satellite station is referred to as uplink). .

The transmission synchronization control section 36 has an offset value register 37 and a transmission frame synchronization counter 38. The transmission frame synchronization counter 38 is a synchronization counter that counts up at the same cycle as the transmission frame synchronization counter 16 included in the TDMA control units 14 of the earth station 1 and the earth station 2.

[0014] On the other hand offset value register 37, frame transmission frame synchronization counter 16 value and the earth station 1 or earth station 2 transmit frame synchronization counter 38 has
It holds a difference value (offset value) from the system value (frame number) .

FIG. 4 is an explanatory diagram for explaining the flow of downlink data. In FIG. 4, FIG. 2 or FIG.
2 shows only the part related to the diversity switching. FIG. 5 is an explanatory diagram illustrating the configuration of various data exchanged between the earth station 1 and the earth station 2 and the site diversity control device 3.

In FIG. 4, an earth station 1 and an earth station 2 constitute site diversity, and each satellite station (not shown, the station mounted on an artificial satellite such as a communication satellite) has the same frequency. , The synchronization for communication at the same timing is established. However, earth station 1 or earth station 2
From the positional relationship between the satellite and the satellite station, the reception synchronization is independently controlled by the reception frame synchronization counter 15 included in each.

Data from the satellite stations received by the earth station 1 and the earth station 2 are sent to the site diversity control device 3 by ATM communication. Receiving data at this time, the reception synchronization of the differences in the respective earth stations 1, 2, and affected by the transmission delay to earth stations 1 and earth station 2 and the site diversity control unit 3. Therefore, in the site diversity control device 3, a time difference occurs between the received data from the earth stations 1 and 2 with respect to the same data.

For this reason, the earth station 1 and the earth station 2 receive the received frame value (frame) for the communication data from the satellite station.
Number of the received frame value notification message D64 (1 of the control message)
One) periodically notify the site diversity control unit 3 (see FIG. 5).

On the site diversity device 3 side, the frame aligners 35-1 and 35-1 of the frame aligner 35 are based on the data of each frame value (frame number) .
The received data is once stored in 35-2 , and is switched at the same frame break by the switch 35a. This allows
Absorb the time difference due to the propagation delay.

In this switching, the switching control unit 31 of the site diversity control device 3 selects either the earth station 1 or the earth station 2 as the operation side in order to enable more stable communication. .

This selection operation is controlled by transmitting a communication status notification message D65 (one of control messages) of the satellite station transmitted from the earth station control unit 11 of each of the earth station 1 and the earth station 2.
It is performed based on.

FIG. 6 is an explanatory diagram for explaining the flow of uplink data. In FIG. 6 , FIG.
2 shows only the part related to the diversity switching.

In FIG. 6, the site diversity controller 3 operates the transmission frame synchronization counter 38 of the transmission synchronization control unit 36 at the same clock frequency as the transmission frame synchronization counter 16 of the earth station 1 or 2.

However, since the synchronization of the transmission frame synchronization counters 38 , 16 and 16 is controlled independently of each other, the three transmission frame synchronization counters 38 , 16 and 16
16 are given different offset values, and operate with clocks of the same frequency.

Moreover earth station 1, 2 each transmission frame synchronization counter 16 is controlling the transmission synchronization for a single satellite station, the difference is up to the satellite station according to geographic location relationship of the earth stations 1 This is due to the difference in distance.

On the other hand, the transmission frame synchronization counter 38 of the site diversity control device 3 basically operates autonomously. However, this site diversity control device 3
Periodically transmit frame value notification message D61 (1 of control message)
One) (with reference to FIG. 5), the frame value of the transmit frame sync counter 38 informs the earth station 1.

The earth station 1 sends a transmission frame value notification message D61 (one of the control messages) from the site diversity control device 3.
When the message is received, the value of the transmission frame synchronization counter 16 is compared with the content thereof, and the difference value is compared with the transmission frame difference value notification message D.
A response is sent to the site diversity control device 3 by 63 (one of the control messages) .

The site diversity control device 3 transmits the transmission frame difference value notification message D63 (1 of the control message) from the earth station 1.
) Is set in the offset value register 37 of the transmission synchronization control unit 36.

During the above operation, the transmission frame synchronization counter 38 of the site diversity controller 3 keeps the earth station 1
Autonomously operates at the same clock frequency as the transmission frame synchronization counter 16 of FIG.

For this reason, the difference value set in the offset value register 37 becomes almost constant even at the time of periodic updating. However, when viewed from a long time axis, the fluctuation of the transmission frame synchronization counter 16 of the earth station 1 due to the fluctuation of the position of the satellite station and the error between the clock frequency of the transmission frame synchronization counter 16 and the clock frequency of the transmission frame synchronization counter 38 cause It is expected to change slowly.

In this embodiment, an appropriate time interval is set.
And the diversity control means (site diversity control
Between the station 3) and the earth station 1 on the working side.
Statement D62 (one of control messages) and transmission frame difference value notification message
By notifying statement D63 (one of the control messages),
Offset holding means (offset value register 37)
Repeat the update periodically.

Here, the diversity control means (cytoda
The ivacity controller 3) transmits arbitrary user data
The transmission frame counting means (transmission frame
And the offset holding means.
(Offset value register 37)
The user data arrives at earth station 1
The transmitted frame value used by earth station 1 at the time
(Frame number) (= second transmission frame counting means (transmission
The value indicated by the transmission frame synchronization counter 16).
It becomes possible. This is because the offset holding means (E
2 of the earth station 1 held in the offset value register 37).
Transmission frame counting means (transmission frame synchronization counter 1)
6) and diversity control means (site diversity control)
First transmission frame counting means (transmission frame
The difference value of the synchronization counter 38) is determined by the transmission frame as described above.
Value notification message D61 (one of control messages) and transmission frame
Performed by sending and receiving the system difference value notification message D63 (one of the control messages)
The diversity control means (site diversity
ATM transmission from the security controller 3) to the working earth station 1
One-way transmission delay (= transmission frame value notification message D61 (control
The transmission delay of one of the telegrams is also included.
This is because it is the value obtained.

This means that the delay of the transmission time due to the transmission delay from the site diversity control device 3 to the earth station 1 is absorbed by the above-described difference correction using the offset value.

In the above situation, when it is necessary to change the operation from the earth station 1 to the earth station 2, the site diversity controller 3 switches the switch 36a so that the data transmission to the earth station 1 is transmitted to the earth station 2. Control.

At this time, the site diversity control device 3
Is the transmission frame value (frame number) at which the earth station 2 starts transmitting to the satellite station before transmitting data to the earth station 2.
) To the transmission frame value indication message D62 (1 of the control message).
One) (using the FIG. 5) instructs the earth station 2.

At this time, the transmission frame value indication message D62 (control
Frame value (frame number ) notified by one of the
) Is a value obtained by correcting the value indicated by the transmission frame synchronization counter 38 by the value of the offset value register 37.

In this case, the earth station 2 sends the designated frame
Transmission does not start before the value (frame number) , and transmission to the satellite station starts after the designated frame value (frame number) . This prevents the data transmitted from the site diversity controller 3 to the earth station 2 from colliding with the satellite station overtaking the final data transmitted to the earth station 1.

The above-mentioned switching of site diversity is performed by:
As explained in the downlink data switching operation,
In order to enable more stable communication, the switching controller 31 of the site diversity control device 3 controls the switch 36a to select either the earth station 1 or the earth station 2 as the operation side. This operation is performed by transmitting a communication status notification message D65 (one of control messages) of the satellite station transmitted from the earth station control unit 11 of each of the earth station 1 and the earth station 2.
It is performed based on.

After the site diversity switch is executed, the operation before the switch is performed in the earth station 2 which is a new operation station. That site diversity control unit 3 periodically full transmission frame synchronization counter 38
By transmitting the frame value to the earth station 2 and setting the transmission frame difference value returned from the earth station 2 in the offset value register 37, the transmission timing of the earth station 2 is grasped.

FIG. 7 is a timing chart showing the timing for switching the site diversity for the uplink data in the present embodiment as described above.

[0041] In Figure 7, the earth station 1 is working, whereas a earth station 2 is in the preliminary state, satellite stations and position of earth stations 1
The positioning relationship is that earth station 1 is farther from satellite station than earth station 2.
Have . As a result, the earth station 1 transmits a frame earlier than the earth station 2 for the same frame on the satellite station.

For example, consider the case where diversity switching occurs immediately after the data cell C3 is transmitted from the site diversity control device 3 to the earth station 1. In this case, the earth station 1 transmits the last data cell C at the timing when it can be transmitted to the satellite station by adding it to the satellite station frame value F3 (frame number).
3 has been received.

On the other hand, the transmission data after the data cell C4 is transmitted to the earth station 2, but since the earth station 2 is closer to the satellite station than the earth station 1, the data of the data cell C4 is transmitted to the satellite station frame.
It can be transmitted in the frame of the frame value F1 (frame number) .

However, when the earth station 2 receives the satellite station frame value F4
Using frames before (frame number)
This means that the frame used in the earth station 1 overlaps. For this reason, the site diversity control device 3 instructs the earth station 2 in advance the satellite station frame value F4 (frame number) expected to be used when the data cell C4 is continuously transmitted to the earth station 1. As a result, the satellite station frame value F
The use of frames prior to 3 (frame number) by the earth station 2 is prohibited, and the overlapping use of frames between the earth station 1 and the earth station 2 is prevented.

On the other hand, when the switching from the earth station 2 to the earth station 1 occurs, the same control is performed. At this time, in the case of the positional relationship between the earth station 1 and the earth station 2 shown in FIG. 7, it is impossible to use the frames used by the earth station 2 in the earth station 1 redundantly. Therefore, off after the values inevitably site diversity control unit 3 instructs
Inherit communication using the frame value (frame number) .

Although the above embodiment has been described on the assumption that the TDMA satellite communication network is connected to a general-purpose terrestrial communication network, the present invention is not limited to the terrestrial protocol of ATM.

That is, the ATM communication unit is connected to an IP (Internet)
Protocol) and ISDN (Integrated Services Digital)
It is also possible to replace the communication interface with another terrestrial protocol communication interface such as a network (integrated service digital communication network).

[0048]

As described above, according to the present invention, among the information transmitted to a plurality of earth stations after being given a unique frame value by the satellite station and divided into a plurality of frames, the communication state is changed. The diversity control means selects the best information, and the arrangement means rearranges the frames in the order of the unique frame values . Further, each difference between the result of counting the number of frames by the first transmission frame counting means of the transmission synchronization control means and the result of counting the number of frames by the second transmission frame counting means of each of the plurality of earth stations is offset. Since the timing of the frame to be transmitted is held by the holding means and is instructed to a plurality of earth stations, it is possible to realize a diversity control device which does not cause loss of information or collision in time-division information exchange. Can be

That is, according to the present invention, in the connection between the TDMA satellite communication network and the terrestrial communication network, when the satellite terrestrial station has a site diversity configuration, the connection from the terrestrial network occurs due to the geographical relationship between the working station and the standby station. Even when there is a difference in the amount of transmission delay when transmitting data to each of the working station and the protection station, or when the transmission synchronization timings in satellite communication between the working station and the protection station are independent, the site diversity is used in the current operation. Data duplication and loss can be prevented when switching between stations / standby stations.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a diversity control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed internal configuration of the earth station in the embodiment.

FIG. 3 is a block diagram showing a detailed internal configuration of the site diversity control device according to the embodiment.

FIG. 4 is an explanatory diagram illustrating a flow of downlink data according to the embodiment.

FIG. 5 is an explanatory diagram illustrating a configuration of various data exchanged between an earth station and a site diversity control device in the embodiment.

FIG. 6 is an explanatory diagram illustrating a flow of uplink data according to the embodiment.

FIG. 7 is a timing chart showing timing for switching site diversity for uplink data in the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 , 2 Earth station 3 Site diversity control device (diversity control means) 4 Terrestrial ATM network 11 Earth station control unit 12 RF unit 13 MODEM unit 14 TDMA control unit 15 Reception frame synchronization counter (reception frame counting unit) 16 Transmission frame synchronization counter (Second transmission frame counting unit) 17 ATM communication unit 31 Switching control unit (switching control unit) 32 ATM communication unit 33-1 , 33-2 ATM communication unit 35 Frame aligner (arraying unit) 35-1 , 36-2 Frame aligners 35a , 36a Switch 36 Transmission synchronization control unit (transmission synchronization control unit) 37 Offset value register (offset holding unit) 38 Transmission frame synchronization counter (first transmission frame counting unit)

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 7/00 H04B ⁷ /02-7/195 H04B 7/22 H04L 1/02-1/06

Claims (7)

(57) [Claims] 1. A frame value unique to each satellite station is
A method for exchanging information divided into a plurality of given frames
Communication between a number of earth stations (1,2) and the satellite station of the plurality of earth stations (1,2)
Diversity control means to select the best earth station
(3), wherein the diversity control means (3) receives the plurality of received
Array for rearranging the frames in the order of the unique frame values
Means (35) for communication between the satellite station and the earth station (1, 2).
Communication with the TDMA system, and with the earth station (1, 2)
Communication between terrestrial data transceivers in data format
Communicate in frames with no frame value
Earth stations with site diversity configuration (1,
In contrast to 2), the earth station (1) is connected to the working earth station (1).
Earth station (2) is the spare earth station (2)
From the working earth station (1) to the protection earth station (1).
When switching occurs in (2), the working earth station
Both (1) and the standby earth station (2) receive from the satellite station.
From which frame position of the transmitting TDMA frame
Replace or replace with a new working earth station (2)
From any frame position of the transmitted TDMA frame
A diversity control device for controlling whether to perform system transmission. Wherein said plurality of earth stations (1, 2), the unique off by counting the number of said frames, each received
The diversity control device according to claim 1, further comprising a received frame counting means (15) for determining a frame value . 3. The diversity control means (3) controls timing of the frame to be transmitted by the plurality of earth stations.
3. The diversity control device according to claim 2, further comprising a transmission synchronization control unit (36) for instructing (1, 2) . Wherein said transmitting synchronization control means (36), said specific frame by counting the number of the frames to be transmitted
4. The diversity control device according to claim 3, further comprising a first transmission frame counting means for determining a transmission value . 5. A second transmission for each of the plurality of earth stations (1, 2) for counting the number of the frames and transmitting a frame having the unique frame value at a predetermined timing. 5. Diversity control device according to claim 4 , characterized in that it comprises a frame counting means (16). 6. The transmission synchronization control means (36) comprises: a first transmission frame counting means (38) ;
The diversity control device according to claim 5, further comprising an offset holding unit (37) for holding each difference from a result of the second transmission frame counting unit (16) . 7. The transmission synchronization control means (36) includes switching control means (31) for selectively switching the plurality of earth stations (1, 2) , and said first transmission frame counting means (38). ) And the counting result
Difference from the result of the second transmission frame counting means (16)
The first transmission frame counting means (38) and the
And the offset of the second transmission frame counting means (16).
The diversity control device according to claim 6, wherein the control value is updated .