JP2795055B2 - Transmission power control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control system for controlling the transmission power of an earth station so as to make the power reaching a transponder constant by compensating for rain attenuation in the uplink in a satellite communication system. The present invention relates to transmission power control for controlling transmission power in accordance with the operation mode of.

[0002]

2. Description of the Related Art In a transmission power control method, a rain attenuation amount in an uplink is estimated from a reception level measured on a reception side, and the transmission power is controlled by feeding back to a transmission side. It is an effective means for improving line quality.

In a satellite communication system in which a plurality of earth stations communicate using a plurality of carriers via a plurality of transponders, the input / output characteristics of each transponder are measured at each earth station, and the operating point of a specific transponder is determined. And the difference between the operating points of the other transponders corresponding thereto as the inter-transponder correction value, obtain the transmission power control amount of the own station using the specific transponder, add the inter-transponder correction value to the transmission power control amount, 2. Description of the Related Art A transmission power control method for a plurality of transponders for controlling transmission power from an earth station to a satellite for each transponder as a transmission power control value of a transponder is known. FIG. 4 shows a configuration example in which the conventional transmission power control method of a plurality of transponders is applied to TDMA communication. FIG. 5 shows an example of a frame configuration of TDMA satellite communication in the case where two carriers are transmitted per transponder.

In the reference station 1, the operation characteristics of the transponder are measured in fine weather. The transmission power is changed according to an instruction from the operating point measurement unit 2 to the transmission power control unit 3 to change the input power to the satellite 20, the own-station closed-loop signal returned by the satellite 20 is received, and the reception power of the reception signal is received. Is measured by the operating point measuring unit 2 to obtain the transponder operating characteristics of the transmission power versus the reception power. Based on the operating characteristics, a predetermined back-off is performed from the saturation point of the received power (ie, the output power of the transponder) to determine the optimum output power, and the optimum input power (ie, the optimum operating point) is determined from the optimum output power. The above measurement is performed for all transponders, and the difference between the optimum operating point and the reception synchronous transponder is set as a transponder correction value.

[0005] Transmission power control of the reference station is performed as follows.
In the reference station 1, the attenuation detector 4 estimates the rainfall attenuation in the uplink by the own station closed loop using the own station burst via the carrier of the reception synchronous transponder (for example, the F1 carrier of T1 in FIG. 5) and transmits the same. The power control amount 5 is calculated. The inter-transponder correction value 6 obtained by the above measurement is added to the control amount to obtain a transmission power control value, and the transmission power control unit 3 controls the own station transmission power based on the transmission power control value. Transponders other than the reception synchronous transponder, which are reference transponders, can operate at the optimum operating point of each transponder by adding a transponder correction value.

[0006] The transmission power control of the slave station is performed as follows. In the reference station 1, the inter-transponder correction value 6 obtained by the above measurement is transmitted to all slave stations via the control line. In addition, the slave synchronization (N) burst transmitted from each slave station is monitored, the attenuation detector 4 estimates the rain attenuation in the uplink for each slave station, calculates the transmission power control amount 5, and uses the control amount as a control line. To all slave stations via

In each slave station 11, the inter-transponder correction value sent via the control line is used as a transponder (for example, T in FIG. 5) which sends its own slave synchronization (N) burst.
The deviation between the correction value of 2) and the correction values of other transponders is set as the inter-transponder correction value 12 again. Similarly, the inter-transponder correction value 12 is added to the transmission power control amount 13 sent on the control line to obtain a transmission power control value, and the transmission power control unit 14 controls the own station transmission power based on the transmission power control value. Transponders other than the transponders transmitting their own slave synchronization (N) bursts can operate at the optimum operating point of each transponder by adding a transponder correction value.

[0008]

In the conventional system, usually, a case where all carriers are operated in each transponder (FIG. 6-a shows an example in which a maximum of eight carriers are transmitted per transponder). Assuming an optimal operating point, a transponder correction value is calculated. By the way, a case where all carriers are not used in a certain transponder due to traffic fluctuation (FIGS. 6B and 6C) may occur. In this case, it is advantageous to set the operating point per carrier high so that the total power of the used carrier becomes the optimal operating point of the transponder (FIG. 6-d).

However, in the conventional method, the operation is performed at the operating point assuming the operation of all carriers regardless of the operation mode of the transponder. Therefore, when the number of operating carriers is reduced, the operation at the optimum operating point is not necessarily performed. It has the disadvantage of not being able to.

An object of the present invention is to provide a transmission power control system using a plurality of carriers by a plurality of transponders, wherein the operating points of the transponders are corrected in accordance with the operation mode of the transponder, and all transponders are optimized regardless of the operation mode of the transponder. To operate at the operating point.

[0011]

SUMMARY OF THE INVENTION A feature of the present invention is to provide a satellite communication system for performing communication using a plurality of carriers from a plurality of earth stations via a plurality of transponders, and compensating for rainfall attenuation in an uplink to a transponder. A transmission power control method that keeps the arrival power of each transponder constant regardless of the amount of rain attenuation.Each earth station measures the operating characteristics of each transponder and calculates the difference between the operating point of a specific transponder and the corresponding operating point of each transponder. The transponder correction value is obtained as a transponder correction value, and the transponder correction value is calibrated to control the transponder transmission power according to the number of carriers per transponder, and the transmission power control amount of the own station using a predetermined transponder is determined. Between the transponders, the transmission power control amount being calibrated by the transponder operation mode. It was added, and a transmission power control value of each transponder in the transmit power control scheme according to the operating mode of a transponder for controlling the transmission power of each transponder.

[0012]

According to the present invention, the earth station corrects the transponder operating point per carrier according to the operation state of each transponder. Compared to the conventional technology, each transponder can be operated at an optimum point, and the line quality can be improved.

[0013]

Embodiment 1 FIG. 1 shows a first embodiment of the present invention and operates as follows.

The operation characteristics of the transponder are measured in fine weather. The transmission power is changed according to an instruction from the operating point measurement unit 2 to the transmission power control unit 3 to change the input power to the satellite 20, the own-station closed-loop signal returned by the satellite 20 is received, and the reception power of the reception signal is received. Is measured by the operating point measuring unit 2 to obtain the transponder operating characteristics of the transmission power versus the reception power. Based on the operating characteristics, a predetermined back-off is performed from the saturation point of the received power (ie, the output power of the transponder) to determine the optimum output power, and the optimum input power (ie, the optimum operating point) is determined from the optimum output power. The above measurement is performed for all transponders, and the difference between the optimum operating point and the reception synchronous transponder is set as a transponder correction value.

The own-station closed-loop using the own-station burst via the carrier of the reception synchronous transponder (for example, the F1 carrier at T1 in FIG. 5) estimates the amount of rainfall attenuation in the uplink by the attenuation detector 4 and transmits the transmission power. The control amount 5 is calculated. The correction value control unit 8 calibrates the inter-transponder correction value obtained by the above measurement to a value corresponding to the change of the operating point based on the transponder operation information, and calculates a new trans-ponder correction value 6. The transmission power control value 5 is added to the inter-transponder correction value to obtain a transmission power control value, and the transmission power control unit 3 controls the transmission power of the own station using the transmission power control value.

According to this system, transponders other than the reception synchronous transponder, which are reference transponders, can operate at the optimum operating point of each transponder by adding a transponder correction value regardless of the operation mode of the transponder. I have.

Embodiment 2 FIG. 2 shows a second embodiment of the present invention, and operates as follows.

In the reference station 1, as in the first embodiment, the inter-transponder correction value is obtained by the operating point measuring unit 2 and the inter-transponder correction value obtained by the above-mentioned measurement is obtained by the correction value control unit 8 to determine the operating point based on the transponder operation information. It is calibrated to a value corresponding to the change, and is calculated again as a transponder correction value 6. The inter-transponder correction value is transmitted to all slave stations via the control line.

In each slave station 11, the inter-transponder correction value sent via the control line is transmitted to the transponder (for example, T in FIG. 5) which sends its own slave synchronization (N) burst.
The deviation between the correction value of 2) and the correction values of other transponders is set as the inter-transponder correction value 12 again. In addition, the attenuation detector 16 estimates the amount of rain attenuation in the uplink and calculates the transmission power control amount 13 by the closed loop using the slave synchronization (N) burst transmitted by the own station. The inter-transponder correction value 12 is added to the control amount 13 to obtain a transmission power control value, and the transmission power control unit 14 controls the transmission power of the own station based on the transmission power control value.

According to the present system, transponders other than the transponder transmitting the slave synchronization (N) burst of the own station are added by adding the inter-transponder correction value regardless of the operation mode of the transponder. It can be operated at the optimum operating point.

Embodiment 3 FIG. 3 shows a third embodiment of the present invention, and operates as follows.

In the reference station 1, similarly to the first embodiment, the inter-transponder correction value is obtained by the operating point measuring section 2 and the inter-transponder correction value obtained by the above-mentioned measurement is corrected by the correction value control section 8 to determine the operating point based on the transponder operation information. It is calibrated to a value corresponding to the change, and is calculated again as a transponder correction value 6. In addition, slave station synchronization (N) transmitted by each slave station
The burst is monitored, and the attenuation detector 4 estimates the rain attenuation in the uplink to calculate the transmission power control amount 5.
The transponder correction value 6 and the transmission power control amount 5
To all slave stations via the control line.

Each slave station 11 uses the inter-transponder correction value sent via the control line as a transponder which transmits its own slave synchronization (N) burst (for example, T in FIG. 5).
The deviation between the correction value of 2) and the correction values of other transponders is set as the inter-transponder correction value 12 again. Similarly, the inter-transponder correction value 12 is added to the transmitted transmission power control amount 13 to obtain a transmission power control value, and the transmission power control unit 14 controls the local station transmission power based on the transmission power control value. According to this method, the optimum operation of each transponder can be achieved by adding the inter-transponder correction value to transponders other than the transponder that is transmitting its own slave synchronization (N) burst, regardless of the operation mode of the transponder. It is operable at the point.

[0024]

As described above, according to the present invention, even if the operation mode of the transponder fluctuates in transmission power control using a plurality of transponders, the difference in the operating point of each transponder at a specific earth station (reference station) is obtained. Is corrected, all the transponders can be operated at the optimum operating point, and the line quality can be improved.

[0000]

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention.

FIG. 2 shows a second embodiment of the present invention.

FIG. 3 shows a third embodiment of the present invention.

FIG. 4 shows an embodiment of a conventional transmission power control method for a plurality of transponders.

FIG. 5 shows a configuration example of a TDMA frame when a plurality of transponders are used.

FIG. 6 shows an example of a transponder operation state.

[Description of Signs] 1 Reference station 2 Operating point measurement unit 3 Transmission power control unit 4 Attenuation amount calculation unit 5 Transmission power control amount 6 Transponder correction value 7 Combining unit 8 Correction value control unit 11 Slave station 12 Transponder correction value 13 Transmission power Control amount 14 Transmission power control unit 15 Separation unit 16 Attenuation calculation unit 20 Satellite T1 to T3 Transponder number F1 to F6 Carrier number R Reference station synchronization burst N Slave station synchronization burst D Data burst

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 7/14-7/22

Claims (3)

(57) [Claims] In a transmission power control system for making a power reaching a transponder constant in a satellite communication system for performing communication using at least one carrier from an earth station via a plurality of transponders, each transponder is connected to each earth station. Means for measuring the operating characteristics of each transponder from the operating characteristics, obtaining the difference between the operating points of each transponder from the operating point of a specific transponder as a transponder correction value, and the number of carriers per transponder. Means for calibrating the inter-transponder correction value to control the uplink transmission power according to the following: means for determining a transmission power control value of a specific earth station using a predetermined transponder; The above-mentioned correction value between transponders is added to the transmission power control value of each transponder. Transmission power control scheme is set to a value, and having means for controlling the transmission power of each transponder. 2. An inter-transponder correction value is obtained at a specific earth station, and the inter-transponder correction value calibrated in accordance with the number of carriers per transponder is periodically transmitted to all earth stations. 2. The transmission power control method according to claim 1, wherein the transponder correction value is added to the determined transmission power control amount, and the transmission power control value of each transponder is used to control the transmission power of each transponder. 3. The inter-transponder correction value and the transmission power control amount for each earth station, wherein the inter-transponder correction value and the transmission power control amount for each earth station are determined at a specific earth station and calibrated according to the number of carriers per transponder. The transmission power control method according to claim 1, wherein the transmission power is transmitted to all earth stations, and each earth station controls the transmission power of each transponder according to the transmission power control amount and the transponder correction value.