KR0159360B1 - Site diversity system in satellite communication and the method for the same - Google Patents

Abstract

The present invention relates to a site diversity system and method for use in a satellite communication system, a central earth station of a micro earth station system, and a satellite broadcasting transmitting earth station system to prevent a decrease in transmission quality due to rainfall attenuation and interruption of communication / broadcasting. If the difference in coral attenuation between two earth stations that differs depending on the attenuation size based on the attenuation amount of the main earth station is smaller than the defined weight, the main earth station is selected. In order to provide a site diversity system and a method for accurately operating a diversity switching operation by selecting a spare earth station only when exceeding it, a primary transmitting earth station for detecting rainfall attenuation and monitoring the state of the system 1 And preliminary transmitting earth station 5; And diversity control means (7) for receiving the state and rainfall attenuation information of the system from the primary transmitting earth station (1) and the preliminary transmitting earth station (5) and controlling the diversity switching operation. In this case, the difference in signal attenuation between two earth stations is calculated, and if the difference in signal attenuation is smaller than the predetermined reference value, the main earth station is selected, and if the reference value is exceeded, the diversity switching operation is controlled so as to select a reserve earth station. The effect is to improve quality degradation and reduce downtime for telecommunications / broadcasting systems.

Description

Site diversity system and method thereof for satellite communication.

1 is a block diagram of a site diversity system according to the present invention.

2 is a flow chart in accordance with the present invention.

* Explanation of symbols for the main parts of the drawings

1: Main Transmitting-Earth Station

2: communication link between the main transmitting earth station and the satellite

3: Satellite

4: Diversity Interconnection Link

5: Back-up Transmitting-Earth Station

6: communication link between a preliminary transmitting earth station and a satellite

7: Diversity Controller

The present invention relates to a satellite communication system using a frequency band of 10 GHz or more, a central earth station of a Very Small Aperature Teminal (VSAT) system that transmits to several small earth stations, and a satellite broadcasting transmitting earth station system. The present invention relates to a site diversity system and a method used to prevent degradation of power quality and interruption of communication / broadcasting.

Addresses the problem of degradation of transmission quality and communication interruption caused by rainfall attenuation, which is one of the biggest disadvantages of 14 / 12GHz Ku-band or 20 / 30GHz Ka-band satellite communication systems using frequency bands above 10GHz. Although the site diversity communication method used to originally originated from terrestrial microwave communication. Recently, as the frequency band used up to the car band, it is essential to improve the transmission quality and reduce the communication downtime in the satellite communication system.

In the conventional site diversity method, when the signal of the currently selected and operating path is lower than the reference value and at the same time lower than the signal of the other waiting path without distinction between the two earth stations, the switching is generated and the standby station is selected and continues to operate. For example, if the main earth station and the preliminary earth station are distinguished and the signal quality of both paths is higher than the predetermined reference value, the switching occurs only when the main earth station path is selected and the signal quality is lower than the reference value and lower than that of the reserve earth station. If this condition is not satisfied, the main earth station is selected again, and if the amount of rainfall attenuation of the selected earth station is greater than the first attenuation threshold, the amount of attenuation is increased after confirming that the power of the corresponding transmitting earth station is increased by a certain amount and is less than the first attenuation threshold. If larger than this second attenuation threshold There is a method of switching the data shows that a power increase in the previous step is insufficient to another transmitter.

As such, the conventional methods set a reference value to prevent switching operation that may occur frequently regardless of rainfall due to antenna tracking error and signal variation, and compare the rainfall attenuation sizes of two earth stations only for the attenuation exceeding the reference value. In combination with the transmit power control function, for small attenuations, the transmit power is increased and switching is only performed when the threshold is exceeded.

Therefore, the conventional method has a problem in that unnecessary switching occurs frequently regardless of rainfall due to antenna tracking error and signal variation because switching is performed by comparing the attenuation sizes of two earth stations.

In order to solve the problems of the prior art, the present invention distinguishes between the main earth station and the spare earth station, so that the difference in signal attenuation between two earth stations differently determined according to the attenuation size based on the attenuation amount of the main earth station is smaller than a predetermined reference value. In this case, an object of the present invention is to provide a site diversity system and a method of accurately operating a diversity switching by selecting a primary earth station and selecting a spare earth station only when the attenuation vehicle exceeds a reference value.

In order to achieve the above object, the present invention multiplexes transmission data input from the outside, modulates a carrier wave into a multiplexed signal, converts the carrier frequency into a satellite frequency, amplifies the signal to high power, and transmits the signal to the satellite. A main transmitting earth station that detects rainfall attenuation using a signal and monitors the state of the system; The multiplexed signal is input from the main transmitting earth station through the diversity connection link, and the carrier wave is modulated into the multiplexed signal to be converted into a satellite frequency and then transmitted to the satellite, and the amount of rainfall attenuation is received using the signal received from the satellite. A preliminary transmitting earth station for detecting and monitoring the status of the system; And receiving the state and rainfall attenuation information of the system from the main transmitting station and the preliminary transmitting earth station, and obtaining the difference in signal attenuation between the two earth stations. If the difference in signal attenuation is smaller than the defined weight, the main earth station is selected and the reference value is exceeded. If so, the diversity control means for controlling the diversity switching operation to select a spare earth station.

In order to achieve the above object, the method of the present invention multiplexes transmission data input from the outside, modulates a carrier wave into a multiplexed signal, converts the carrier frequency into a satellite frequency, amplifies it to high power, and transmits the signal to the satellite and receives the signal from the satellite. A primary transmitting earth station which detects the amount of rainfall attenuation using and monitors the state of the system; When the multiplexed signal is input from the earth station during the main transmission link, the carrier wave is modulated by the multiplexed signal to be converted into a satellite frequency, and then transmitted to the satellite and the rainfall attenuation is obtained by using the signal received from the satellite. A preliminary transmitting earth station for detecting and monitoring the status of the system; And receiving the state and rainfall attenuation information of the system from the main transmitting station and the preliminary transmitting earth station to obtain the difference in signal attenuation between the two earth stations, and selecting the main earth station only if the difference in signal attenuation is smaller than the predetermined reference value. In the case of a site diversity method applied to a site diversity system having a diversity control means for controlling a diversity switching operation to select a spare earth station, the main transmitting earth station monitors the state of the system. Selecting a path of the preliminary transmitting earth station if the status of the preliminary transmitting earth station is not normal and detecting the rainfall attenuation amount if the main transmitting earth station is normal; And, in the case of the primary transmitting earth station, the magnitude of the attenuation is greater than the first rainfall reduction amount reference value, and the amount of rainfall attenuation of the primary transmitting earth station is between the first rainfall reduction amount reference value and the second rainfall reduction amount reference value, Is not smaller than the first attenuation difference reference value, the amount of rainfall attenuation of the primary transmitting earth station is larger than the amount of rainfall attenuation of the preliminary transmitting earth station, and the amount of rainfall attenuation of the main transmitting earth station is larger than the first rainfall attenuation amount reference value, The amount of rainfall attenuation of the primary transmitting earth station is not between the first rainfall attenuation amount reference value and the second rainfall attenuation amount reference value, and the attenuation difference between the primary transmitting earth station and the preliminary transmitting earth station is not smaller than the second attenuation amount difference reference value, The amount of rainfall attenuation is equal to the amount of rainfall attenuation of the preliminary transmitting earth station. For the case is large, select the path of the preliminary transmission earth station, and the rest, it characterized in that it comprises a second step of selecting the path of the primary transmission earth station.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of a site diversity system according to the present invention, where 1 is a Main Transmitting-Earth Station, 2 is a communication link between a main transmitting earth station and a satellite, 3 is a satellite, and 4 is a diver. Diversity Interconnection Link, 5 denotes a back-up Transmitting-Earth Station, 6 denotes a communication link between the reserve transmitting earth station and the satellite, and 7 denotes a diversity controller.

The main transmitting earth station 1 multiplexes the transmission data input from the outside, modulates the carrier wave into a multiplexed signal, converts it to satellite frequency, amplifies it to high power, and then provides a communication link between the main transmitting earth station 1 and the satellite 3 ( It transmits to the satellite via 2), detects the amount of rainfall attenuation using the signal received from the satellite 3, and monitors the state of the system.

The preliminary transmitting earth station 5 receives the multiplexed signal from the primary transmitting earth station 1 through the diversity connection link 4, modulates a carrier wave into a multiplexed signal, and converts it into a satellite frequency. It transmits to the satellite 3 via the communication link 6 between the satellite and the satellite 3, and detects the amount of rainfall attenuation using the signal received from the satellite 3 and monitors the state of the system.

The diversity controller 7 receives the state and rainfall attenuation information of the system from the main transmitting earth station 1 and the preliminary transmitting earth station 5, and calculates the difference of mutual attenuation between the two earth stations based on the attenuation amount of the main earth station. The diversity switching operation is controlled to select a main earth station when the difference between the attenuations is smaller than a predetermined reference value and to select a spare earth station when the reference value is exceeded.

2 is a flowchart of switching control of site diversity according to the present invention.

First, the state of the system is monitored (8) to determine if the state of the primary transmitting earth station is normal (9) if the primary transmitting earth station 1 is not normal to determine whether the standby state of the preliminary transmitting earth station 5 is normal ( 11) If the preliminary transmitting earth station 5 is normal, select the path of the preliminary transmitting earth station 5 (17) and repeat the process from the system status monitoring process (8). Maintain and repeat from the system status monitoring process (8).

If the primary transmitting earth station 1 is normal, the rainfall attenuation amount is detected (10), and if the rainfall attenuation amount of the primary transmitting earth station 1 is larger than the first rainfall attenuation amount reference value (12), if it is not large, the main transmitting earth station is selected ( 18) The system state monitoring process (8) is repeated, and if it is large, it is determined whether the amount of rainfall attenuation of the primary transmitting earth station 1 is between the first rainfall attenuation reference value and the second rainfall attenuation reference value.

If the amount of rainfall attenuation of the primary transmitting earth station 1 is between the first rainfall attenuation reference value and the second rainfall attenuation reference value, whether the difference between the primary transmitting earth station 1 and the preliminary transmitting earth station 5 is smaller than the first attenuation difference standard value. If it is determined (14) that it is small, it selects the primary transmitting earth station (1) path (18) and repeats from the system state three-way process (8), otherwise the magnitude of the rainfall attenuation of the primary transmitting earth station 1 is the preliminary transmitting earth station (5). If it is larger than the amount of rainfall attenuation (16), if it is large, select the preliminary transmitting earth station (5), and if it is not large, select the main transmitting earth station (1), and then (18) Repeat it.

On the other hand, if the magnitude of the rainfall attenuation of the primary transmitting earth station 1 is not between the first rainfall attenuation reference value and the second rainfall attenuation reference value, the difference between the attenuation amounts between the main transmitting earth station 1 and the preliminary transmitting earth station 5 is the second attenuation difference reference value. If it is small (15), if it is small, select the main transmitting earth station (1) path (18) and repeat the system state monitoring process (8), if not smaller, the amount of rainfall attenuation of the main transmitting earth station (1) is preliminarily transmitted. It is determined whether the earth station 5 is larger than the amount of rainfall attenuation (16), and if it is large, the preliminary transmitting earth station (5) path is selected (17) if it is not large (18) after the main transmitting earth station (1) path is selected (18). Repeat from 8).

As described above, the present invention selects a spare earth station only when the attenuation amount is greater than the reference value and the difference between the two earth stations that is determined differently according to the magnitude of the attenuation amount is larger than the reference value, thereby causing unnecessary switching operation due to antenna tracking error or signal variation. Diversity method that does not have the feature of reducing the transmission quality and reducing the downtime of the communication / broadcasting system due to the locally generated rainfall attenuation in the satellite communication / broadcasting system using the frequency band above 10GHz. have.

Claims (4)

The transmission data input from the outside is multiplexed, the carrier wave is modulated by the multiplexed signal, converted to satellite frequency, amplified to high power, transmitted to the satellite (3), and the rainfall attenuation using the signal received from the inter-satellite (3). A primary transmitting earth station 1 which detects and the system monitors the status; The multiplexed signal is inputted from the main transmitting earth station 1 through the diversity connection link 4, and the carrier wave is modulated into the multiplexed signal, converted into a satellite frequency, and then transmitted to the satellite 3 and the satellite 3 A preliminary transmitting earth station 5 which detects the amount of rainfall attenuation by using the signal received from the second monitor and monitors the state of the system; And receiving the state and rainfall attenuation information of the system from the primary transmitting earth station (1) and the preliminary transmitting earth station (5), and obtaining a difference in signal attenuation between the two earth stations. If the difference in signal attenuation is smaller than a predetermined reference value, the primary earth station is selected. And a diversity control means (7) for controlling the diversity switching operation so as to select a spare earth station when the reference value is exceeded. In a site diversity method applied to a site diversity system, the state of the preliminary transmitting earth station (1) is monitored if the state of the primary transmitting earth station (1) is not normal and the state of the preliminary transmitting earth station (5) is normal. A first step (8 to 11,17) of selecting a path of 5) and detecting rainfall attenuation amount if the main transmitting earth station 1 is normal; And the amount of rainfall attenuation of the primary transmitting earth station 1 is greater than the first rainfall attenuation amount reference value, and the amount of rainfall attenuation of the main sending earth station 1 is between the first rainfall attenuation amount reference value and the second rainfall attenuation amount reference value. When the attenuation amount difference between the transmitting earth station 1 and the preliminary transmitting earth station 5 is not smaller than the first attenuation amount difference reference value, and the amount of rainfall attenuation of the primary transmitting earth station 1 is larger than that of the preliminary transmitting earth station 5. And the amount of rainfall attenuation of the primary transmitting earth station 1 is larger than the first rainfall attenuation amount reference value, and the amount of rainfall attenuation of the main transmitting earth station 1 is not between the first rainfall attenuation amount reference value and the second rainfall attenuation amount reference value. The attenuation difference of the primary transmitting earth station 1 and the preliminary transmitting earth station 5 is not smaller than the second attenuation difference standard value, and the magnitude of the rainfall attenuation of the main transmitting earth station 1 is the preliminary transmitting earth station 5. And a second step (12 to 18) of selecting a path of the preliminary transmitting earth station 5 when the rainfall attenuation amount is greater than the size of the preliminary transmitting earth station 5, and otherwise selecting a path of the main transmitting earth station 18. Featured Site Diversity Method. 3. The method of claim 2, wherein the first steps (8 to 11, 17) comprise: a third step (8, 9) of monitoring the state of the system to determine whether the state of the primary transmitting earth station (1) is normal; As a result of the determination in the third step (8, 9), if the main transmitting earth station 1 is not normal, it is determined whether the state of the preliminary transmitting earth station 5 is normal, and if the preliminary transmitting earth station 5 is normal, Select the path of the preliminary transmitting earth station 5 and repeat the process from the system state monitoring process 8, and if the preliminary transmitting earth station 5 is not normal, maintain the current state and repeat from the system state monitoring process 8 Performing fourth steps (11, 17); And a fifth step (10) of detecting rainfall attenuation when the main transmitting earth station (1) is normal as a result of the determination of the third step (8, 9). . 3. The method of claim 2, wherein the second steps 12 to 18 determine whether the magnitude of the rainfall attenuation amount of the primary transmitting earth station 1 is greater than the first rainfall reduction amount reference value, and selecting the primary transmitting earth station if it is not large. Third steps 12 and 18 which are repeated from the state monitoring process 8; As a result of the determination in the third step (12,18); if the amount of rainfall attenuation of the primary transmitting earth station 1 is larger than the first rainfall attenuation amount reference value, the amount of rainfall attenuation of the main transmitting earth station 1 is the first rainfall attenuation amount A fourth step 13 of determining whether the reference value is between the second rainfall reduction amount reference value; As a result of the determination in the fourth step 13, if the amount of rainfall attenuation of the primary transmitting earth station 1 is between the first rainfall attenuation reference value and the second rainfall attenuation reference value, the primary transmitting earth station 1 and the preliminary transmitting earth station ( If it is determined that the attenuation amount difference in 5) is smaller than the first attenuation amount difference reference value, the path of the main transmitting earth station 1 is selected and repeated from the system state monitoring process 8, and if it is not small, the main transmitting earth station 1 If it is determined that the amount of rainfall attenuation is greater than the amount of rainfall attenuation of the preliminary transmitting earth station 5, the path of the preliminary transmitting earth station 5 is selected. A fifth step (14, 16 to 18) to repeat the process (8); And if it is determined in the fourth step 13 that the magnitude of the rainfall reduction amount of the primary transmitting earth station 1 is not between the first rainfall reduction amount reference value and the second rainfall reduction amount reference value, the primary transmission earth station 1 and the preliminary transmission. If it is determined that the attenuation amount difference of the earth station 5 is smaller than the second attenuation amount difference reference value, the path of the main transmitting earth station 1 is selected and the system state monitoring process 8 is repeated. If the magnitude of the rainfall attenuation of 1) is greater than that of the rainfall attenuation amount of the preliminary transmitting earth station 5, it is determined that the preliminary transmitting earth station 5 path is selected. Site diversity method comprising a sixth step (15 to 18) to be repeated from the determination process.