KR101895845B1 - Method for blocking compensation in mobile satellite communication - Google Patents

Method for blocking compensation in mobile satellite communication Download PDF

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Publication number
KR101895845B1
KR101895845B1 KR1020180075244A KR20180075244A KR101895845B1 KR 101895845 B1 KR101895845 B1 KR 101895845B1 KR 1020180075244 A KR1020180075244 A KR 1020180075244A KR 20180075244 A KR20180075244 A KR 20180075244A KR 101895845 B1 KR101895845 B1 KR 101895845B1
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KR
South Korea
Prior art keywords
traffic
state
blocking
blocking state
long
Prior art date
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KR1020180075244A
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Korean (ko)
Inventor
홍근표
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한화시스템 주식회사
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B17/00Monitoring; Testing
    • H04B17/40Monitoring; Testing of relay systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems
    • H04B7/185Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18532Arrangements for managing transmission, i.e. for transporting data or a signalling message
    • H04B7/18534Arrangements for managing transmission, i.e. for transporting data or a signalling message for enhancing link reliablility, e.g. satellites diversity

Abstract

A blocking compensation method in a mobile satellite communication system is disclosed. The method includes the steps of: determining a blocking state in which a satellite radio wave is blocked by monitoring a traffic state; checking whether the blocking is in a short blocking state or a long blocking state, if a determination result is the blocking state; and transmitting data according to a variable MAC diversity scheme in the short blocking state and maintaining a traffic mode according to a traffic reception state in the long blocking state according to a check result. Accordingly, the present invention can perform smooth satellite communication in an environment in which a radio wave interference element exists.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for compensating a blocking in a mobile satellite communication system,

The present invention relates to a blocking compensation method in a mobile satellite communication system, and more particularly, to a blocking compensation method in a mobile satellite communication system that enables satellite communication without disruption even in the presence of radio interference elements.

In general, a satellite communication system is composed of a satellite, a base station that performs communication by relaying with the satellite, and a terminal (satellite communication modem) that transmits and receives the satellite on the ground.

The mobile satellite communication system is widely used for commercial and military purposes because the terminal (satellite communication modem) is installed in a mobile body such as a vehicle, a train, and a ship and provides network connectivity and mobility to mobile terminals spread over a very wide area. .

Such a mobile satellite communication system has a problem that smooth satellite communication is not performed because satellite radio waves are blocked due to various radio disturbance factors such as tunnels, trees, electric poles, bridges, and high-rise buildings.

Korean Patent Registration No. 10-1524555 (Publication date 2015.05.29.)

SUMMARY OF THE INVENTION The present invention has been conceived to solve such a problem, and it is an object of the present invention to grasp a short blocking state and a long blocking state according to a traffic state, to transmit data by a variable MAC diversity method according to the detected state, It is an object of the present invention to provide a blocking compensation method in a mobile satellite communication system that enables satellite communication without disruption even in an environment where there are radio wave interference elements by maintaining a traffic mode or releasing a call.

According to another aspect of the present invention, there is provided a method of compensating a blocking in a mobile satellite communication system, comprising: monitoring a traffic state to determine whether a satellite signal is blocked; Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state; And transmitting the data according to the variable MAC diversity scheme in the short blocking state according to the checking result and maintaining the traffic mode according to the traffic receiving state in the long blocking state.

In one embodiment of the present invention, it is preferable that the blocking state is determined based on a frame error rate (FER). If the FER exceeds a preset threshold value, the blocking state is determined.

A blocking compensation method in a mobile satellite communication system according to another embodiment of the present invention includes: monitoring a traffic state to determine whether a satellite wave is blocking; Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state; Transmitting the data according to a variable MAC diversity scheme when it is determined in the short blocking state; And monitoring the traffic reception state to maintain the traffic mode or release the call if the long blocking state is determined as a result of the checking.

In another embodiment of the present invention, in the case of the long blocking state as a result of the checking, monitoring the traffic reception state to maintain the traffic mode or release the call may include monitoring the traffic reception state, Maintaining the traffic mode; And monitoring the traffic reception state to release the call if the traffic is not received within a predetermined time.

A blocking compensation method in a mobile satellite communication system according to another embodiment of the present invention includes: monitoring a traffic state to determine whether a satellite wave is blocking; Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state; If it is determined that the MAC PDU is in the short blocking state, repeatedly transmitting the same MAC PDU until a new MAC PDU is generated; And monitoring the traffic reception state to maintain the traffic mode or release the call if the long blocking state is determined as a result of the checking.

In another embodiment of the present invention, the confirmation of whether the blocking is in a short blocking state or a long blocking state may be made by confirming a short blocking state if the blocking period is within a preset time, It is desirable to confirm the state of blocking.

A blocking compensation method in a mobile satellite communication system according to another embodiment of the present invention includes: monitoring a traffic state to determine whether a satellite wave is blocking; Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state; If the result of the determination is a short blocking state, repeatedly transmitting the same MAC PDU until a new MAC PDU is generated regardless of ACK / NACK information transmitted from the receiving end; And monitoring the traffic reception state to maintain the traffic mode or release the call if the long blocking state is determined as a result of the checking.

In another embodiment of the present invention, in the case of the long blocking state as a result of the checking, monitoring the traffic reception state to maintain the traffic mode or release the call may include monitoring a traffic reception state, Maintaining the traffic mode if it is determined to be in the traffic mode; And if the traffic is not received within a predetermined time, performing a call release procedure and entering an idle mode.

A blocking compensation method in a mobile satellite communication system according to another embodiment of the present invention includes: monitoring a traffic state to determine whether a satellite wave is blocking; Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state; If it is determined that the MAC PDU is in the short blocking state, repeatedly transmitting the same MAC PDU until a new MAC PDU is generated; Monitoring a traffic reception state when the traffic is in a long blocking state and maintaining a traffic mode when traffic is received within a predetermined time; And releasing the call if no traffic is received within a predetermined time.

In another embodiment of the present invention, the confirmation of whether the blocking is in the short blocking state or the long blocking state may be made by checking the short blocking state when the blocking period is within a predetermined time after entering the blocking state, It is preferable to confirm the long blocking state when a predetermined time has elapsed.

A blocking compensation method in a mobile satellite communication system according to another embodiment of the present invention includes: a mobile terminal requesting a call connection to a base station to perform call setup with the base station; Monitoring a traffic state transmitted and received through the established call to determine whether the satellite radio wave is blocked, Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state; If it is determined that the MAC PDU is in the short blocking state, repeatedly transmitting the same MAC PDU until a new MAC PDU is generated; Monitoring a traffic reception state when the traffic is in a long blocking state and maintaining a traffic mode when traffic is received within a predetermined time; And releasing the call if no traffic is received within a predetermined time.

In the mobile satellite communication system of the present invention, the blocking compensation method measures a short blocking and a long blocking state according to a traffic state, transmits data by a variable MAC diversity scheme according to the detected state, By maintaining the traffic mode or canceling the call, smooth satellite communication is possible even in an environment where radio interference elements exist.

1 is a diagram schematically illustrating a configuration of a mobile satellite communication system to which a blocking compensation method according to the present invention is applied.
2 is a process diagram for explaining a blocking compensation method in a mobile satellite communication system according to an embodiment of the present invention.
3 to 5 are views for explaining a blocking compensation method in a mobile satellite communication system according to the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, a blocking compensation method in a mobile satellite communication system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram schematically illustrating a configuration of a mobile satellite communication system to which a blocking compensation method according to the present invention is applied.

1, the mobile terminal 10 receives a signal from the satellite 30 while it is logged on to the base station 20.

The base station 20 is installed on the ground to transmit data to the mobile terminal 10 and transmits a signal to the satellite 30.

The satellite 30 receives the signal transmitted from the base station 20 and transmits the received signal to the mobile terminal 10 on the ground.

The mobile terminal 10 described above may receive signals from the satellite 30 and may include military equipment such as tanks, armored vehicles, aircraft, submarines, etc. as mobile terminals.

When the mobile terminal 10 detects a blocking state while operating in a traffic mode that is a traffic communication state after powering on and performing call setup with the base station 20, the mobile terminal 10 determines whether the blocking is in a short blocking state, (Long Blocking) state. In the short blocking state, data is transmitted according to a variable MAC (Media Access Control) diversity scheme. In the long blocking state, the traffic mode is maintained according to the traffic reception state Release the call.

Hereinafter, a call setup process between the mobile terminal 10 and the base station 20 will be briefly described.

When the mobile terminal 10 is powered on, it receives a pilot channel transmitted in a broadcast manner from the base station 20 and corrects the downlink initial frequency offset.

Thereafter, the mobile station receives the network control channel to acquire satellite downlink synchronization, and acquires satellite uplink synchronization through the terminal synchronization channel.

The mobile terminal 10 which acquires the satellite downlink and the satellite uplink synchronization requests the log-on to the base station 20 through the network subscription channel, periodically reports the logon completion and the terminal status through the terminal status channel, Requests traffic resource allocation to the base station 20 through a network subscription channel and performs traffic communication through a traffic channel when a resource is allocated in response to a resource allocation request.

When the traffic communication is terminated, call termination and call release are requested to the base station 20 through the network subscription channel to perform call release.

2 is a process diagram for explaining a blocking compensation method in a mobile satellite communication system according to an embodiment of the present invention.

If the mobile terminal 10 is logged on to the base station 20 and is in a standby state in an idle mode in step S10 and a call setup request is received in step S20, Allocates resources, and establishes a call with the base station 20 (S30).

When the mobile terminal 10 allocates resources from the base station 20 and sets up a call with the base station 20 through the step S30, the operation mode is switched to the traffic mode and traffic communication with the base station 20 is performed through the traffic channel (S40).

As described above, the operation mode of the mobile terminal 10 can be divided into the idle mode and the traffic mode. The idle mode is a mode in which the mobile terminal 10 is logged in the base station 20, Acquires synchronization, and periodically reports the terminal status through the terminal synchronization channel.

The traffic mode is a state in which a call is established with the base station 20 and traffic communication is performed through a traffic channel.

When the operation mode of the mobile terminal 10 is switched to the traffic mode through the above step S40, the traffic state is monitored (S50), and it is determined whether or not a blocking state in which the satellite radio wave is blocked due to various radio wave interference factors (S60).

In step S60, whether a blocking state has occurred can be determined based on a frame error rate (FER). If the FER exceeds a predetermined threshold value, the blocking state can be determined.

If the FER exceeds the predetermined threshold value, it is determined that the apparatus enters the blocking state as shown in FIG. 3 (Fsi). If the FER which has exceeded the predetermined threshold value falls below the threshold value, It is judged to return to the non-blocking state (Fse).

The period from the entry of the blocking state to the exit of the blocking state is called the blocking period Tbt. As shown in Fig. 3, due to the blocking detection delay time alpha and the blocking end detection delay time beta There may be a difference between the actual blocking period x and the blocking period recognized by the mobile terminal 10.

The FER is statistically estimated using a cyclical redundancy check (CRC) result value from the physical layer (PHY) of the modem, and the received signal strength and communication quality information can be utilized as an auxiliary indicator for preventing false alarm .

The FER may be updated by a moving average value through a sliding window scheme of any size Ta.

The size (Ta) of the sliding window, the blocking detection delay time (?), The blocking end detection delay time (?), The FER threshold value and the like can be expressed as AFD (Average Fading Duration), ACD The initial value can be estimated by utilizing the time ratio Bt and the level crossing rate (LCR) value, and can be changed through an external GUI (Graphical User Interface) provided for parameter tuning .

If it is determined in step S60 that the blocking state has occurred (S60: Yes), it is checked whether the blocking is short blocking or long blocking (S70)

Whether the blocking occurring in step S60 is short blocking or long blocking is determined by checking whether the state in which the FER of the traffic channel connected between the base station 20 and the mobile terminal 10 is 100% And judges that it is not meaningful to keep the call connection because the state where the FER is 100% exceeds the preset time, it is judged to be in the long blocking state, and until the state where the FER is 100% exceeds the preset time, .

If the blocking resulting from the check in step S70 is short blocking (S70: Yes), the data is repeatedly transmitted according to the variable MAC diversity scheme (S80).

Specifically, when the blocking occurring as a result of the checking in step S70 is a short blocking, the same MAC PDU (for example, PDU2) is generated regardless of ACK / NACK information transmitted from the receiving end (base station) Repeatedly transmits the same MAC PDU (for example, PDU2) repeatedly until a new MAC PDU (e.g., PDU3) is generated.

In addition, as shown in FIG. 5, a predetermined number (for example, three) of MAC PDUs (for example, PDU0, PDU-1, PDU-2) are repeatedly transmitted regardless of ACK / NACK information of the receiving end PDU-1, PDU-2) until a new MAC PDU (e.g., PDU1) is generated. Here, PDU0 is the newly generated and transmitted current data, and PDU-1 and PDU-2 are the previously generated past data.

When a new MAC PDU (e.g., PDU2) is generated, it updates a predetermined number of MAC PDUs to be repeatedly transmitted, and updates the updated MAC PDUs (e.g., PDU2, PDU1, PDU0) Repeated transmission is performed until it is generated.

The reason for repeatedly transmitting data in this manner is to reflect the real-time nature of PDU (Protocol Data Unit) applications as a top priority as much as possible.

If the data is repeatedly transmitted according to the variable MAC diversity scheme as in the embodiment of the present invention, it is not necessary to worry about the number of repeated transmissions according to various channel environments, and the number of repeated transmissions increases , It is possible to increase the transmission success probability and maximize the throughput compared to the fixed MAC diversity scheme.

If it is determined in step S70 that the blocking is long blocking (S70: NO), the traffic communication state of the traffic channel is monitored (S90). If the blocking is received in a first predetermined time in the long blocking state (S100).

If it is determined in step S100 that the traffic is received within the predetermined first time period (S100: Yes), the flow advances to step S40 to maintain the operation mode of the mobile terminal 10 in the traffic mode, And performs traffic communication with the base station 20.

On the other hand, if it is determined in step S100 that no traffic is received within a predetermined first time period (S100: NO), the downlink initial frequency offset is corrected through the pilot channel (S110).

If the downlink initial frequency offset is normally corrected through the pilot channel in step S110, satellite downlink synchronization is acquired through the network control channel in step S120.

After the satellite downlink synchronization is reconfigured through the steps S110 and S120, the traffic communication state of the traffic channel is monitored (S130), and it is confirmed whether the traffic is received within a predetermined second time (S140).

If it is determined in step S140 that the traffic is received within a predetermined second time (S140: YES), the flow advances to step S40 to maintain the operation mode of the mobile terminal 10 in the traffic mode, And performs traffic communication with the base station 20.

If it is determined in step S140 that the traffic is not received within the second predetermined time period (S140: NO), the call release procedure is performed (S150). In step S150, .

On the other hand, if it is determined in step S110 that the downlink initial frequency offset can not be corrected through the pilot channel (for example, the pilot channel can not be received due to an antenna error, an exception process, etc.) Perform call release procedure.

If it is determined in step S120 that satellite downlink synchronization can not be obtained through the network control channel, the process proceeds to step S110 and the downlink initial frequency offset is corrected again through the pilot channel

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

10. Mobile terminal, 20. Base station,
30. Satellite

Claims (5)

  1. Monitoring a traffic state to determine whether the satellite radio wave is in a blocked state;
    Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state;
    If the result of the determination is a short blocking state, repeatedly transmitting the same MAC PDU until a new MAC PDU is generated regardless of ACK / NACK information transmitted from the receiving end; And
    And monitoring the traffic reception status to maintain the traffic mode or release the call if the long blocking state is confirmed as a result of the checking.
  2. The method according to claim 1,
    Wherein the step of monitoring a traffic reception state to maintain a traffic mode or release a call in the long blocking state includes:
    Monitoring a traffic reception state and maintaining a traffic mode if traffic is received within a predetermined time; And
    And if the traffic is not received within a predetermined time, performing a call release procedure and entering an idle mode.
  3. Monitoring a traffic state to determine whether the satellite radio wave is in a blocked state;
    Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state;
    If it is determined that the MAC PDU is in the short blocking state, repeatedly transmitting the same MAC PDU until a new MAC PDU is generated;
    Monitoring a traffic reception state when the traffic is in a long blocking state and maintaining a traffic mode when traffic is received within a predetermined time; And
    And releasing the call if no traffic is received within a predetermined time. ≪ Desc / Clms Page number 21 >
  4. The method of claim 3,
    The confirmation of whether the blocking is in the short blocking state or in the long blocking state,
    Blocking state when the blocking period is within a predetermined time after the mobile station enters the blocking state and confirms the long blocking state when the blocking period exceeds the predetermined time.
  5. The mobile terminal requests a call connection to the base station and performs call setup with the base station;
    Monitoring a traffic state transmitted and received through the established call to determine whether the satellite radio wave is blocked,
    Determining whether the blocking is in a short blocking state or a long blocking state when the determination result is that the blocking state is a blocking state;
    If it is determined that the MAC PDU is in the short blocking state, repeatedly transmitting the same MAC PDU until a new MAC PDU is generated;
    Monitoring a traffic reception state when the traffic is in a long blocking state and maintaining a traffic mode when traffic is received within a predetermined time; And
    And releasing the call if no traffic is received within a predetermined time. ≪ Desc / Clms Page number 21 >
KR1020180075244A 2018-06-29 2018-06-29 Method for blocking compensation in mobile satellite communication KR101895845B1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100273648B1 (en) * 1998-12-08 2000-12-15 윤종용 Method for decreasing a call drop rate of mobile telephone in a cellular system
KR100404732B1 (en) * 1997-03-21 2003-11-07 에릭슨 인크. Satellite telecommunications repeaters and retransmission methods
JP2014096795A (en) * 2012-11-01 2014-05-22 Boeing Co Satellite communications data processing
KR101524555B1 (en) 2014-07-02 2015-05-29 아주대학교산학협력단 Method and Apparatus for controlling satellite communication

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100404732B1 (en) * 1997-03-21 2003-11-07 에릭슨 인크. Satellite telecommunications repeaters and retransmission methods
KR100273648B1 (en) * 1998-12-08 2000-12-15 윤종용 Method for decreasing a call drop rate of mobile telephone in a cellular system
JP2014096795A (en) * 2012-11-01 2014-05-22 Boeing Co Satellite communications data processing
KR101524555B1 (en) 2014-07-02 2015-05-29 아주대학교산학협력단 Method and Apparatus for controlling satellite communication

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