JPH0454025A - Satellite channel demand allocating device - Google Patents

Abstract

PURPOSE:To apply transmission power control to all of assigned lines and to warrant the quality of the line by receiving the information of a control state of transmission power from a transmission power controller and changing the allocation condition of a satellite channel accordingly so as to control the assignment and the utilization of the satellite channel. CONSTITUTION:The satellite channel management section 20 of a satellite channel demand allocation device has an interface section 21 with the control section 8 of a transmission power controller 6, inputs the control state information of the transmission power controller 6 and discriminates the information together with the operating state information of the satellite channel. Whether or not a line is to be allocated to a demand assignment requirement is discriminated. Moreover, the transmission power controller 6 is basically the same as that of a conventional device. Then the satellite channel management section 20 controls the number of satellite channels to be allocated so that the maximum number of the satellite channels to be allocated is limited small in comparison with the case with less transmission power when the transmission power per transmission carrier is much at the point of time of the occurrence of the demand assignment requirement.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a satellite line demand allocation device used in a satellite communications earth station.

(Prior Art) The present invention relates to a satellite line demand allocation device in a satellite communication earth station, and is closely related to a transmission power control device in a satellite communication earth station. Therefore, first we will discuss the transmission power control device, and then we will discuss the conventional technology of the satellite line demand allocation device.

(1) About the transmission power control device One satellite communication port has a particularly high frequency band (for example, 14/
11G) Iz band, 30/20 GHz band, etc.), radio wave attenuation due to rain on the propagation path between the satellite and the earth becomes a problem. Since the signal strength decreases due to rain attenuation, signal quality such as bit error rate deteriorates. As a countermeasure against rain attenuation, there is transmission power control that adapts to the amount of attenuation and increases the transmission power by the amount to cancel it.

Transmission power control can be broadly divided into: ■ Uplink transmission power control (Up-1ink Power
Control: UPC), ■Downlink transmission power control (Down-1ink Pow
er C-control: DPC).

UPC compensates for rain attenuation in the propagation path from the earth station to the satellite. The amount of attenuation to be compensated is determined using the level of the beacon wave from the satellite, etc., and the power of all carriers transmitted from the earth station is uniformly increased.

On the other hand, DPC compensates for rain attenuation in the propagation path from the satellite to the destination earth station. Since the rain attenuation situation differs depending on the location of the destination earth station, the amount of compensation differs for each transmitted carrier wave. In other words, DPC has practical meaning only in 5CPC/FDMA. A method for the earth station to know the amount of attenuation that should be compensated is to monitor the line quality at the destination earth station and have it sent back (Kono et al., 14/11 GHz band V
SAT System Laboratory Experiment, Institute of Electronics, Information and Communication Engineers, Satellite Communication System Study Group, 5AT88-4. June 1988)
etc.

FIG. 5 shows an example of an apparatus configuration in which both UPC and DPC are performed. The earth station consists of an antenna l, a transmitter 2, a receiver 3, a modulator 4 and a demodulator 5. Normally, the transmission power control device 6 is functionally inserted between the modem and the transmitter/receiver.

The transmission power control device 6 includes a variable attenuator 7 that changes the power.
, a control unit 8 that instructs and controls the amount of attenuation to the variable attenuator 7;
It consists of a part that obtains information about the amount of attenuation that should be set. When a variable attenuator is used to control power, the attenuation amount of the attenuator is maximized when there is no rain attenuation, and the attenuation amount of the attenuator is set to 0 for the maximum rain attenuation to be compensated.

When using the satellite beacon wave level, which is one method of obtaining the compensation amount for UPC (uplink rain attenuation amount), from the beacon wave receiver 9 and its level measurement circuit 10 (or C/N measurement circuit) measurement information is input to the control section 8. The change in beacon level is based on the downlink frequency (1
Since this is for the 11 GHz band in the case of the 4/11 GHz band, the control unit 8 converts it into a correction amount at the uplink frequency (14 GHz band in the case of the 14/11 GHz band). An instruction is issued to the variable attenuator 7 from. Since the amount of compensation for UPC is the same for all communication carriers, the same value is set for all variable attenuators.

One way to obtain the compensation amount for DPC (downlink rain attenuation amount) is to have the destination earth station monitor the line quality and send it back, as described above, in which case the line quality information is obtained from the demodulated signal. is extracted and inputted to the control unit 8. The control unit 8 estimates the downlink attenuation amount from the uplink attenuation amount described above and this line quality information (influences of both the uplink and downlink are combined). Since the amount of compensation for DPC differs for each communication carrier, the corresponding variable attenuator 7 is set based on the line quality information from the demodulator 5 corresponding to each carrier.

(2) About the satellite line demand allocation device The satellite line demand allocation device does not always set and use satellite lines between earth stations, but instead allocates and uses satellite lines each time according to demand requests. It is a control device. A satellite link can be shared and used by more earth stations and terminals than there are satellite links. Hereinafter, the earth station that performs all management related to satellite line allocation will be referred to as a hub station, and the plurality of earth stations that issue satellite line allocation requests to the hub station will be referred to as remote stations. The satellite line demand allocation device according to the present invention relates to a device on the hub station side. Here 5CPC/FDM
An example of the configuration of a conventional satellite line demand allocation device for A is shown in FIG. The satellite line demand allocation device in the same figure is
Signaling processing unit 11. It is composed of a call processing section 12, a satellite line management section 13, and a device control section 14. The signaling processing unit 11 receives and processes demand allocation requests from remote earth stations and terminals connected to the hub earth station. The satellite line management unit 13 manages the usage status of the satellite line and allocates an appropriate line in response to a demand allocation request. The call processing unit 12 manages various call states and performs processing such as call origination processing and disconnection processing according to the call state. The device control unit 14 controls the modem 15 according to instructions from the call processing unit 12.
Frequency settings, carrier 0n10ff, etc. Which modem is used and what frequency is used for communication is set for each demand allocation request.

(Problems to be Solved by the Invention) However, the above-mentioned conventional device has the following problems when the conventional satellite line demand allocation device is used in an earth station that performs transmission power control. First, conditions regarding controllable power in transmission power control will be described. The number of carriers used (allocated for communication) at a certain point in time at the hub earth station is N, UPC
The increase ratio of the transmission power due to DPC for each carrier is G, (G, ≧1), and the increase ratio of the transmission power due to DPC for each carrier is G, , (G, ≧1, i = 1., , , N ),
When the normal power of each carrier (the value during clear weather when no transmission power control is performed) is all 1 for simplicity, the total transmission power of the earth station is expressed by the following equation.

After undergoing rain attenuation in the uplink, the power reaching the satellite will be greater by Ps than in normal times.

When using the transmission power control device, the following conditions are imposed.

Constraint ■: Pt must be within the upper limit of the transmittable power of the earth station.

Constraint condition (2): PS is limited to a certain value due to the condition that the satellite transponder is not saturated or the condition of the satellite power that is allowed to be used by the earth station.

In other words, even if transmission power control is used, if extremely heavy rain falls on the earth station in question, or large rainfall attenuation occurs at the same time on multiple destination earth stations, the rain attenuation may not be fully compensated due to the constraints imposed by these conditions. In that case, the transmission power control device performs control as shown in the following two examples.

(a) Reduce the power of all carriers little by little■,
■ Make sure that the conditions are met. In this case, signal quality deteriorates in all satellite lines.

(b) The condition is satisfied by sufficiently reducing the power of some carriers (particularly carriers with high transmission power). In this case, the signal quality of these carriers will be extremely degraded or the lines will essentially be disconnected.

Conventional satellite line demand allocation equipment sequentially allocates carriers in response to demand requests, so ultimately the maximum number of carriers that can be physically allocated (usually one modulator/demodulator
Allocate lines up to number 5). Therefore, when rain attenuation occurs, the above two power restrictions may be violated. In other words, the conventional satellite line demand allocation apparatus has a problem in that it allocates lines without taking into account the power control status of the transmission power control apparatus or the rain attenuation situation. In order to perform such line allocation, the power limit will be violated, and the transmission power control device will perform avoidance operations as described in (a) and (b) above.
There was a problem in that the line quality could not be guaranteed for the allocated line.

The present invention is intended to solve the above-mentioned problems of the conventional technology.The present invention is intended to solve the problems of the conventional technology described above. The purpose is to provide an allocation device.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a transmission power control device and a transmission power control device in a satellite communication hub earth station that has a transmission power control device and manages satellite line allocation. When a satellite line allocation request is made from or to a remote earth station, the transmission power control status information is obtained from the transmission power control device through the interface, and the The present invention is characterized in that it includes a satellite line management section that controls the allocation and use of satellite lines by changing the satellite line demand allocation conditions.

(Operation) According to the present invention having the above-described configuration, the satellite line demand allocation device inputs information on the transmission power control status from the transmission power control device, and changes the satellite line allocation conditions accordingly. . Specifically, by limiting the number of actually allocated satellite lines to be less than the physically allocatable number of lines (for example, the number of modems), line quality is guaranteed for the allocated lines. Typically, when there is a lot of rain attenuation, allocation control is performed while limiting the upper limit of line allocation.

Therefore, the present invention can solve the above-mentioned problems, and can provide a satellite line demand allocation device that can perform necessary transmission power control on all allocated lines and guarantee line quality.

(Embodiment 1) FIG. 1 shows a first example of a satellite line demand allocation device according to the present invention.
FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 6 indicate the same components, and the different components include: the satellite line management section 20 has an interface section 21 with the control section 8 of the transmission power control device 6; By inputting the control state information of the control device 6 and making a judgment together with the usage status information of the satellite line, it is determined whether or not to allocate a line in response to the demand allocation request.

The transmission power control device 6 is basically the same as the conventional device shown in FIG. 5, and the variable attenuator 7, level measurement circuit IO, etc. included in the device are omitted in FIG. There is.

The details of the demand allocation processing algorithm in the satellite line demand allocation apparatus according to this embodiment will be described.

Let Nl11 be the number of modems 15 (the upper limit of the number of satellite lines that can be allocated to the earth station), and N be the number of lines already allocated at a certain point in time. The increase rate of transmission power due to UPC at that time (common to N lines) is G, (G,
≧1), the increase ratio of the transmission power by DPC for each line is G
With a variable attenuator that can change up to 0 dB, =0.0
1).

At that point, the transmission power control device is operating so as to satisfy the above-mentioned constraints (1) and (2).

Here, Pt, and P- are respective upper limit values due to the constraint conditions (1) and (2), and are given as constant values in advance.

Here, it is assumed that a satellite line demand allocation request is generated from a remote earth station or a terminal connected to the hub earth station.

In conventional devices, if N+1≦N, a line is allocated.

In the device according to the first embodiment, lines are allocated when all of the following three conditions are satisfied.

N+1≦N (5) L.

In the above formula, K, (K, ≦1) and 2 (K2≦1
) is a control parameter of this device that corresponds to a margin for changes in rainfall conditions after line allocation.

In this embodiment, the complexity of control and the conditions for the number of allocated lines vary depending on how K1 and K2 are handled. In the first and simplest case, K1 and K2 are constant constants. In this case, it is necessary to set a value that corresponds to the worst situation that should be considered regarding the temporal change in rainfall attenuation. K
In selecting the values of 1 and 2, the connection duration of the line is an important factor. If the connection duration is long on average, the rain attenuation situation may change significantly after the line is connected, so the margin should be set larger than when the connection duration is short on average. 2 must be set to a small value. In any case, by limiting the number of satellite lines actually allocated in this way, the necessary transmission power control can be performed for all allocated lines. The line quality can be guaranteed.In the second case, which provides more advanced control, the values of and are changed depending on the value of G.If Gu is large (
If the uplink attenuation is large, set 2 thicker to and than if Gu is small. If Gu is large enough, set 2 to 1. This means that the uplink attenuation is This is based on the fact that all N+1 channels are affected and that when Gu is large, the absolute number of lines that can be allocated is small, so less margin is required.According to the second method, the first method Since the margin is smaller, it is possible to allocate more satellite lines than in the first method while maintaining the feature that line quality can be guaranteed for the allocated lines.

An example of another processing algorithm for the apparatus shown in FIG. 1 will be described below. Instead of formulas (5), (6), and (7), lines are allocated when all of the following three conditions are satisfied.

N+1≦Nm (8)P
t + G u X InaX (G a r )
≦KIXPtfflP g +maX(G 6+
)≦2XP, (10) In the above equation, max() indicates the maximum value when i is changed from 1 to N. The method for setting the values of K and 2 is as follows:
This is the same as the first method or the second method. max
(Ga r )5171 m, so according to the third method, for the same values of 1 and 2, more satellite lines can be allocated than in the first method or the second method. However, if the values of Kl and 2 are set close to 1, and IIIa
When x(GdI) is relatively small, there is a possibility that necessary transmission power control cannot be performed for all allocated lines depending on changes in the rain attenuation situation.

As explained above, in the first embodiment of the present invention, the satellite line management unit 20 of the satellite line demand allocation device
has an interface with the control unit 8 of the transmission power control device 6, and Gu and Ga at (i=1., . . .) are provided as control state information of the transmission power control device.

N) is obtained. The problems of conventional satellite line demand allocation devices are solved by a method of determining whether or not to allocate a line by considering this information when a satellite line demand allocation request occurs. Although three methods are shown here as the first example, the conditions for determining whether or not to allocate a line are as follows from equations (5) to (10) if it includes Gu or G a i. It is not limited.

(Embodiment 2) FIG. 2 shows the second embodiment of the satellite line demand allocation device according to the present invention.
FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. In the same figure, the same reference numerals as in FIG. 1 indicate the same components, and as different components, the satellite line management section 22 has earth station geographical information 23 regarding the geographical information of the earth station and the other earth station. are doing. The satellite line management unit 22 determines whether or not to allocate a line in response to a demand allocation request by combining the usage status information of the satellite line, the control status information of the transmission power control device 6, and the geographical information 23.

Here, the earth station geographic information 23 will be described. The state of rainfall attenuation at two points may be strongly correlated or uncorrelated depending on the geographical relationship (in the simplest terms, distance). The degree of correlation varies depending on the amount of rainfall attenuation. in general,
Strong rainfall resulting in large rainfall attenuation occurs only within a relatively small area (short correlation length), and weak rainfall occurs simultaneously over a relatively wide area. The earth station geographic information 23 stores the average correlation coefficient of rainfall attenuation between the earth station and the destination earth station, as shown in FIG. 3, for example. Third
In the figure, #1 to #lO indicate the numbers of remote earth stations, and the earth stations are hub earth stations that have this demand allocation device. In the case of Figure 3, the hub station and #1 and #2 earth stations have a high correlation coefficient, while the hub station and #9 and #1O earth stations are geographically distant. . This correlation coefficient varies depending on the amount of rain attenuation to be focused on, but since the problem of the conventional technology that the present invention is trying to solve occurs when the amount of rain attenuation becomes large, the correlation coefficient corresponding to the maximum amount of attenuation to be compensated for is Use numbers.

Here, it is assumed that a satellite line demand allocation request is generated from a remote earth station or a terminal connected to the hub earth station. The maximum value of the correlation coefficients between the earth station that is the target of the demand request and the earth station (N station) to which a satellite line has already been assigned is C1.The transmission power by DPC for the earth station that gives the maximum value. Let the increase rate of G(lk) be G(lk).This device accepts this allocation request and allocates the line if all of the following three conditions are met.

N+1≦N m (11) P t
+ (Gu X GaJ X C+ ”L.

≦KI XPtm (12) −CPs +GdkXC+L, xGu ≦K 2
) to the formula (lO) have the same meaning.

Equations (12) and (13) approach the second term on the left side when the correlation coefficient C is large, and approach the third term on the left side when the correlation coefficient C is small (in expressions, Equations (12) and Formula (13
) is not limited to the expression. K, (K, ≦1)
and 2 (K2≦1) may be constants, but the effects of the present invention will be more pronounced if they are changed based on the following rules.

■If the GuQ value is large, increase the value by 2, and increase the value by 2. If the Gu value is small, increase the value by 1 and decrease the value by 2.

■If the average duration of the satellite line connection is long, set 1 and 2 to a small value. If it is short, set K.

Increase 2 to and.

■Correlation coefficient between a total of N+2 stations (total (N+)
2) If (N+1)/2 pieces) is large on average, reduce 1 and 2. If the correlation coefficient is small on average, increase 2 for and.

In this second embodiment, the satellite line management unit 22 obtains the control status information of the transmission power control device 6 from the transmission power control device 6, and also uses the geographical information 23 of the earth station and the other earth station. , solves the problems of conventional satellite line demand allocation devices by using a method of determining whether or not to allocate a line in response to a demand allocation request. The second embodiment is more complex than the first embodiment because it requires geographical information 23, but the situation of rain attenuation is taken into account more accurately, so the margin (K, which is equivalent to 2) is ), and as a result, more () lines can be allocated.

(Embodiment 3) FIG. 4 shows the third embodiment of the satellite line demand allocation device according to the present invention.
FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. In the same figure, the same reference numerals as in FIG. Using the usage information, the control status information of the transmission power control device, and the rainfall intensity distribution information, it is determined whether or not to allocate a line in response to the demand allocation request. The rainfall intensity distribution information 25 holds the rainfall situation at or around the location of the hub earth station or remote earth station, and is updated at regular intervals. One way to obtain and update rainfall information is to use AMeDAS information, which provides online data. Furthermore, since the remote earth station measures the amount of compensation for DPC control, there is also a method of sending the measured value to the hub earth station at regular intervals even when not in communication. When a demand allocation request for a satellite line is generated from a remote earth station or a terminal connected to the hub earth station, in this embodiment as well as in the device according to the first embodiment, equations (5) to (7) are used. or formula (8)
A line is allocated when all three conditions of equation (10) are satisfied. In this embodiment, K, (K,≦1) and 2 (K2≦1) are set based on the following rules.

(2) If the value of G is large, make 1 and 2 thicker. If the value of Gu is small, make 1 and 2 smaller.

■If the satellite line connection duration is long on average, reduce 1 and 2. If it is short, increase 1 and 2.

(2) From the rainfall intensity distribution information 25, if there is little rainfall in the service area as a whole, increase 2 and 2.

■If there is an area with strong rainfall in the ``surroundings'' of the earth station where the demand allocation request was made, K1 and 2
The definition of "surroundings" is wide if the satellite line connection duration is long on average or the data update interval of rainfall intensity distribution information is long, and narrow if vice versa.

In this third embodiment, the rainfall intensity distribution information 25 changes over time and it is necessary to collect data over the entire service area, making it more complicated than the second embodiment, but it allows the situation of rain attenuation to be more accurately determined. Since this is taken into account, the margin (corresponding to Kl and 2) is small, and as a result, more lines can be allocated.

(Effects of the Invention) As explained above, according to the satellite line demand allocation device according to the present invention, the necessary transmission power control can be performed for the lines that are allocated and in use, and the line quality can be guaranteed for those lines. You can allocate lines as follows. Furthermore, the satellite line demand allocation device retains data regarding the average correlation coefficient of rainfall attenuation between earth stations based on the geographical relationship of the earth stations, or data regarding rainfall intensity distribution information within the service area. This method can allocate more satellite lines than the first method while maintaining the feature that line quality can be guaranteed for the lines.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the second embodiment of the present invention, and FIG. 3 shows the contents of the earth station geographic information 23. 4 is a block diagram showing the configuration of a third embodiment of the present invention. FIG. 5 is a diagram illustrating the configuration of a satellite communication earth station that performs transmission power control. , FIG. 6 is a block diagram showing the configuration of a conventional satellite line demand allocation device. 6... Transmission power control device, 8... Control unit, 11... Signaling processing unit, 12... Call processing unit, 13, 20.22.24... Satellite line management unit, 14
...Device control section, 15.Modulator/demodulator, 21.Interface section, 23..Earth station geographic information, 25..Rainfall intensity distribution information.

Claims (4)

[Claims] (1) In a satellite communication hub earth station that has a transmission power control device and manages satellite line allocation, it has an interface with the transmission power control device and receives signals from multiple remote earth stations or from a remote earth station. When a request to allocate a satellite line to a satellite line is made, transmitting power control status information is obtained from the transmitting power control device through the interface, and satellite line demand allocation conditions are changed according to the control status information to allocate the satellite line. 1. A satellite line demand allocation device comprising a satellite line management unit that performs control for use of the satellite line. (2) The satellite line management unit controls the maximum number of satellite lines to be allocated to be limited when the transmission power per transmission carrier is high at the time the demand allocation request is generated, compared to when it is low. A satellite line demand allocation device according to claim 1. (3) The satellite line management unit connects the satellite line according to data regarding the average correlation coefficient of rainfall attenuation between earth stations based on the geographical relationship between the hub earth station and a plurality of remote earth stations and the control status information. The satellite line demand allocation device according to claim 1, wherein demand allocation conditions are changed. (4) Claim 1, wherein the satellite line management unit changes the satellite line demand allocation conditions according to data regarding rainfall intensity distribution information in a service area including a hub earth station and a plurality of remote earth stations and the control status information. The described satellite line demand allocation device.