KR101691931B1

KR101691931B1 - An apparatus and method for link selection according to resource usage rate in satellite communications network that use multiple frequency bands

Info

Publication number: KR101691931B1
Application number: KR1020150143661A
Authority: KR
Inventors: 조병각; 이주형; 박경열; 이희규; 한이수
Original assignee: 국방과학연구소
Priority date: 2015-10-14
Filing date: 2015-10-14
Publication date: 2017-01-02

Abstract

A path selection device for selecting a link according to the amount of frequency usage in a satellite communication network using a plurality of frequency bands according to the present invention includes a packet path controller which receives traffic data, selects a path to be transmitted, and transmits it to a corresponding band modem; a modem for each frequency band which performs signal modulation and demodulation; an RF device which performs the frequency conversion of a modulated signal into a frequency of the corresponding band; and a multi-band antenna capable of transmitting/receiving a multi-band signal to/from a radio channel. It is possible to cope with rainfall attenuation in a satellite terminal capable of simultaneously communicating with multiple bands and to efficiently use a frequency resource.

Description

TECHNICAL FIELD [0001] The present invention relates to a path selection apparatus and a path selection method for selecting a link according to frequency usage in a satellite communication network using a plurality of frequency bands,

The present invention relates to a link path selection apparatus and a path selection method according to frequency usage in a satellite communication network using a plurality of frequency bands. More particularly, the present invention relates to a link path selection apparatus and a path selection method capable of maintaining smooth traffic distribution and load balancing in a multi-band satellite terminal capable of operating multiple frequency bands at the same time. More particularly, the present invention relates to a link path selection apparatus and a path selection method for determining a load (frequency usage amount) of a network for each frequency band when traffic to be transmitted to a satellite terminal flows, and transmitting the traffic with a low load.

The geostationary satellite communication system has an advantage of being able to support a wide area communication area. However, since many satellite terminals located in a wide area use the same frequency band, frequency resources are insufficient and efficient use of frequency band is very important.

In this paper, we propose a multi-frequency-time-division-multiple access / multiple assignment (TDMA / DAMA) Access technology has been introduced. Currently, most geostationary-satellite communication networks are implemented by MF-TDMA method.

Also, in the case of a satellite terminal, an antenna / RF equipment / modem is constructed so that one terminal can use various frequency bands to use several frequency bands. By this method, the shortage of frequency band is solved, and it is implemented to cope with rainfall attenuation and radio wave interference.

By using MF-TDMA / DAMA type modems installed in each multi-band satellite terminal for each frequency band, it is possible to efficiently use the frequency band of satellite communication and support large-capacity communication. However, in order to efficiently use such a frequency band, there is a problem in that there is no concrete method for distributing the traffic flowing into the terminal in the multi-band satellite communication as appropriate for each band to ensure smooth distribution of traffic and load balancing of the network.

The present invention has been proposed in order to solve such a problem, and aims at efficient utilization of rainfall attenuation and frequency resources.

Another object of the present invention is to ensure the communication quality even in the case of rain attenuation in a plurality of frequency bands.

Another object of the present invention is to efficiently utilize frequency resources according to frequency bandwidth usage in a plurality of frequency bands.

According to another aspect of the present invention, there is provided a path selection device for selecting a link according to an amount of frequency used in a satellite communication network using a plurality of frequency bands according to the present invention, A packet path controller; A modem for each frequency band that performs signal modulation and demodulation; An RF device for performing frequency conversion of the modulated signal to a frequency of the corresponding band; And a multi-band antenna capable of transmitting and receiving multi-band signals over a radio channel, and can cope with rainfall attenuation and frequency resources efficiently in a satellite terminal capable of simultaneously communicating in multiple bands.

According to one embodiment, there is provided a communication system including: a satellite relay for performing relay of a communication signal in an outer space; And a network controller for calculating a usage amount for each frequency band, transmitting information to the satellite communication terminals, and allocating frequencies requested by the satellite communication terminals.

According to an embodiment, the packet path controller can determine a transmission / reception path of traffic data in consideration of a usage amount per frequency band received from the network controller and a signal attenuation in a frequency band in which rainfall damping is severe.

According to one embodiment, the modems in the respective frequency bands measure the signal attenuation due to rainfall in a frequency band in which the rain attenuation is severe among the respective frequency bands, and the packet path controller can consider the path attenuation And provide signal attenuation information to the packet path controller.

According to an embodiment, the multi-band antenna may be composed of a simultaneous multi-band single antenna for transmitting / receiving signals of multiple frequency bands, or may be constituted by antennas for respective frequency bands.

According to an embodiment, the network controller may calculate the frequency usage amount of each frequency band corresponding to the network load to provide information to the satellite communication terminals and allocate the frequency requested by the satellite communication terminals to the MF-TDMA / DAMA system have.

A method for selecting a link according to an amount of frequency usage in a satellite communication network using a plurality of frequency bands according to the present invention includes the steps of: transmitting, by a network controller, a usage amount for each frequency band to all satellite communication terminals; A step in which data traffic flows into a satellite communication terminal; Determining whether rain attenuation has occurred in the satellite communication terminal; Transmitting data traffic to a modem having a low rainfall attenuation when a rain attenuation occurs in the satellite communication terminal; And transmitting the data traffic to the modem having a small frequency band in consideration of the usage amount of each frequency band received from the network controller when the satellite communication terminal has not experienced the rainfall attenuation.

According to one embodiment, the path selection method includes: requesting a modem of a selected band to allocate a frequency of a corresponding band to a network controller in consideration of the rainfall attenuation and frequency usage; Allocating the frequency requested by the network controller according to the MF-TDMA / DAMA scheme and updating the bandwidth usage per band; And transmitting and receiving data traffic by the satellite communication terminal at the allocated frequency.

According to the present invention, it is advantageous to cope with rainfall attenuation and efficiently utilize frequency resources in a satellite terminal capable of simultaneously communicating in multiple bands.

In addition, according to the present invention, when communication in the first frequency band in which rainfall attenuation is severe is discontinued, frequency diversity that replaces the communication path in the second frequency band is used to ensure quality of service (QoS) There is an advantage to be able to do.

According to the present invention, the first frequency band and the second frequency band are automatically allocated by the MF-TDMA / DAMA technique according to the frequency bandwidth usage, Frequency resources can be efficiently utilized.

1 is a diagram showing a detailed configuration of a path selection device for selecting a link according to the frequency usage amount according to the present invention.
FIG. 2 is a conceptual diagram of operations in which multi-band satellite terminals including the path selection device of FIG. 1 according to the present invention are operated.
3 is a flowchart of a path selection method for selecting a link according to an amount of frequency usage in a satellite communication network using a plurality of frequency bands according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It will be possible. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In this regard, in the present invention, regarding the plurality of frequency bands, the X band and the Ka band frequency band are considered. However, the plurality of frequency bands are not limited to the X and Ka bands, but may include a plurality of frequency bands in general.

On the other hand, when operating a multi-band satellite terminal, it is possible to consider a method of allocating and operating the capacity to be used by the terminal for each band. In this case, the router installed in the terminal distributes the traffic to the X band link and the Ka band link in the absence of the rain. On the other hand, when the Ka-band link, which is vulnerable to rainfall due to rainfall, is disconnected, it transmits traffic only to the X band and operates the terminal with a reduced capacity. This method is not a method of sharing the frequency allocated to the satellite communication network but a method of operating in the X band capacity and the Ka band capacity fixedly allocated to the terminal. That is, it is difficult to guarantee QoS (Quality of Service) because the capacity of the terminal is reduced when the system is in the rain. However, applying the sharing scheme to the MF-TDMA / DAMA instead of the fixed allocation of capacity to the UE, the capacity that was operated in the Ka band can be allocated to the X band at the time of the rain. Also, since the communication network shares the frequency rather than the fixed allocation method, if the other terminals do not utilize the frequency, the higher frequency capacity can be supported by using the frequency.

In another approach, a dynamic frequency diversity protocol has been proposed. It is possible to consider a scheme in which an X-band channel is temporarily allocated and used as an alternative path of the Ka-band channel. An X-band frequency pool shared by all terminals is set, and when the Ka-band rain attenuation is detected, rainfall is recognized, and the X-band available band is searched for and allocated to the X-band. On the other hand, when the rain attenuation ends, the X band frequency is returned and the Ka band is used. For this purpose, the X-band frequency for shared use in preparation for the rain attenuation should be set in advance, and the X-band frequency pool is set as shown in Equation 1 below.

here,

Is the shared X-band frequency bandwidth size,

Is a rainfall region among all satellite communication communication areas,

Corresponds to the entire satellite communication area.

Also,

Is the sum of the bandwidths in which the terminals communicate in the Ka band.

This scheme is advantageous in that QoS can be guaranteed because a certain terminal can switch all of the capacity that is used in probability to the X band even when the Ka band rain attenuation is used. However, there is a disadvantage that the X band frequency is wasted if there is no rainfall in the whole area. We will discuss additional techniques for extending communication capacity and improving QoS without wasting the X-band frequency even in the normal absence of rainfall.

Hereinafter, a path selection device and a path selection method for selecting a link according to a frequency usage amount in a satellite communication network using a plurality of frequency bands according to the present invention will be described in detail with reference to the drawings.

The present invention proposes a path selection device and a path selection method for selecting a link according to a frequency usage amount in a satellite communication network using a plurality of frequency bands.

The path selection device and the path selection method of the present invention efficiently utilize coping and frequency resources for rain attenuation in a satellite terminal capable of simultaneously communicating in multiple bands. In addition, the path selection apparatus and the path selection method of the present invention use a frequency diversity that replaces a communication path in a second frequency band when communication in a first frequency band where rainfall attenuation is severe is discontinued, Quality of service). In addition, the first frequency band and the second frequency band are automatically allocated according to the frequency bandwidth usage by the MF-TDMA / DAMA (Multi Frequency-Time Division Multiple Access / Demand Assigned Multiple Access) technique, .

1 is a diagram showing a detailed configuration of a path selection device for selecting a link according to the frequency usage amount according to the present invention.

As shown in FIG. 1, the path selection device 100 includes a packet path controller 110, frequency-band modems 121 and 122, RF devices 131 and 132, and a multi-band antenna 140. In addition, the path selection device may further include a network controller 150 and a satellite repeater 160.

FIG. 2 is a conceptual diagram of operations in which multi-band satellite terminals including the path selection device of FIG. 1 according to the present invention are operated.

Hereinafter, with reference to FIG. 1, a path selection device for selecting a link according to an amount of frequency used in a satellite communication network using a plurality of frequency bands according to an embodiment of the present invention will be described.

The packet path controller 110 selects the path through which the traffic data is input and transmits the path data to the corresponding band modem. That is, the packet path controller 110 substantially determines the frequency band path, and transmits the received data traffic to the modem of the selected path.

In this regard, the packet path controller 110 determines the transmission / reception path of the traffic data in consideration of the usage amount per frequency band received from the network controller 150 and the signal attenuation in the frequency band in which the rain attenuation is severe. To this end, the packet path controller 110 receives information on frequency usage (or network load) by frequency band from a network controller that performs control / management of the entire satellite communication network. In addition, the packet path controller 110 transmits data traffic to a frequency band modem having a small load according to the provided network load information. Also, if a signal intensity is attenuated due to rainfall due to rainfall in the area where the terminal is located, the traffic is transmitted to the X-band modem 121 where signal intensity reduction due to rainfall attenuation does not occur much. In the satellite communication, the X band is hardly attenuated due to rainfall, while the Ka band is very high, resulting in signal attenuation. Further, the present invention is not limited to the frequency bands used in the X and Ka bands described in this specification, and can be applied to other frequency bands.

The modems 121 and 122 per frequency band perform signal modulation and demodulation in respective frequency bands. That is, the modems 121 and 122 perform signal modulation for wirelessly transmitting the traffic transmitted by the packet path controller 110 through the RF device / antenna, and demodulate the received signal in reverse. Meanwhile, the modems 121 and 122 according to the frequency bands measure the signal attenuation due to rainfall in the modem of the frequency band where the rain attenuation is severe among the modems 121 and 122 for the respective frequency bands. Meanwhile, the packet path controller 110 provides signal attenuation information to the packet path controller 110 so that the packet path controller 110 can consider path selection.

The RF devices 131 and 132 frequency-convert the modulated signal to a frequency of the corresponding band.

Meanwhile, the multi-band antenna 140 transmits / receives multi-band signals through a wireless channel. Also, in the multi-band antenna, the multi-band antenna 140 may be composed of a simultaneous multi-band single antenna to transmit and receive signals of multiple frequency bands, or an antenna for each frequency band.

The satellite transponder 160 performs relaying of a communication signal in an outer space.

The network controller 150 calculates the usage amount for each frequency band, transmits information to the satellite communication terminals, and allocates the frequency requested by the satellite communication terminals. Also, the network controller 150 calculates the frequency usage amount of each frequency band corresponding to the network load, and provides information to the satellite communication terminals. In addition, the network controller 150 allocates the frequency requested by the satellite communication terminals in the MF-TDMA / DAMA scheme. In this regard, the above-described process will be described in detail as follows.

The packet path controller 110 can select one of the modems 121 and 122 according to the frequency band. When the data traffic is received from the packet path controller 110, the selected modem requests the network controller 150 to allocate the corresponding frequency band through the control channel connected to the network controller 150.

The network controller 150 allocates the frequency of the corresponding band and transmits the frequency channel information to the corresponding band modem requesting the frequency allocation. At this time, frequency channels are allocated by the MF-TDMA / DAMA scheme to efficiently allocate and operate frequency resources. The frequency modems 121 and 122 modulate the traffic with the allocated frequency and transmit the modulated traffic to the RF devices 131 and 132. The RF devices 131 and 132 convert the frequency into the corresponding band (X band or Ka band) And transmits a signal to the satellite repeater 160 via the multi-band antenna 140. [

FIG. 2 is a flowchart of a path selection method for selecting a link according to a frequency usage amount in a satellite communication network using a plurality of frequency bands according to the present invention.

Hereinafter, with reference to FIG. 2 and FIG. 3, a path selection method for selecting a link according to a frequency usage amount in a satellite communication network using a plurality of frequency bands according to embodiments of the present invention will be described.

Referring to FIG. 2, a path selection method according to the present invention includes a frequency usage transmission step S110, a data traffic inflow step S120, a Ka-band rain attenuation determination step S130, and a traffic transmission step S140 . In addition, the traffic transmission step S140 includes a first traffic transmission step S140a and a second traffic transmission step S140b.

In addition, the path selection method further includes a frequency allocation request step (S150), a frequency usage update step (S160), and a traffic transmission step (S170).

In the step of transmitting the frequency usage amount (S110), the network controller transmits the frequency usage amount (network load) per frequency band to all the satellite communication terminals.

In the data traffic introduction step (S120), data traffic flows into the packet path controller installed in the satellite communication terminal.

The Ka-band rain attenuation determination step (S130) first determines whether the rain attenuation of the Ka-band is attenuated to determine the frequency band path of the incoming traffic.

The traffic transmission step (S140) determines the path according to the usage amount of each frequency band provided by the network controller when the rain attenuation does not occur. That is, in the first traffic transmission step (S140a), the packet path controller transmits traffic to a modem having a small frequency band.

The second traffic transmission step (S140b) determines the path to the X band when the rain attenuation occurs, and transmits the traffic to the X band modem.

In the frequency allocation request step (S150), the modem of the selected band requests allocation of the frequency of the corresponding band to the network controller in consideration of the rainfall attenuation and the frequency usage amount. That is, the modem of the path determined in the traffic transmission step (S140) requests frequency allocation so as to send data traffic to the corresponding band through a control channel connected with the network controller.

In the frequency usage update step (S160), the network controller allocates the frequency requested by the network controller in the MF-TDMA / DAMA scheme and updates the frequency usage amount for each band.

In the traffic transmission step (S170), the satellite communication terminal transmits and receives data traffic at a frequency allocated by the network controller.

As described above, a path selection method and a path selection device for selecting a link according to a network load per frequency band have been described in detail.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. But is not limited to a limited form.

According to an embodiment of the present invention, there is an advantage that the satellite terminal capable of simultaneously communicating in multiple bands can cope with rainfall attenuation and efficiently utilize frequency resources.

According to an embodiment of the present invention, when communication in a first frequency band where rainfall attenuation is severe is discontinued, frequency diversity, which replaces a communication path in a second frequency band, Service) can be guaranteed.

In addition, according to an embodiment of the present invention, the first frequency band and the second frequency band frequency are divided into a plurality of sub-bands by an MF-TDMA / DAMA (Multi Frequency-Time Division Multiple Access / It is advantageous in that the frequency resource can be efficiently utilized.

It is needless to say that the above-described contents in the path selection method and the path selection method for selecting a link according to the network load per frequency band can be used in combination with each other.

Meanwhile, the control unit 120 proposed in the present invention can be implemented by hardware, software, or a combination thereof. Further, the detailed configuration module of the control unit 120 may also be implemented by hardware, software, and a combination thereof.

According to a software implementation, not only the procedures and functions described herein, but also each component may be implemented as a separate software module. Each of the software modules may perform one or more of the functions and operations described herein. Software code can be implemented in a software application written in a suitable programming language. The software code is stored in a memory and can be executed by a controller or a processor.

100: path selector 110: packet path controller
121: X-band modem 122: Ka-band modem
131: X-band RF device 132: Ka-band RF device
140: X band / Ka band multi-band antenna 150: Network controller
160: satellite repeater

Claims

1. A path selection device for selecting a link according to a frequency usage amount in a satellite communication network using a plurality of frequency bands,
A packet path controller for inputting traffic data and selecting a path to be transmitted and transmitting the selected path to the corresponding band modem;
A modem for each frequency band that performs signal modulation and demodulation;
An RF device for performing frequency conversion of the modulated signal to a frequency of the corresponding band;
A multi-band antenna capable of transmitting and receiving a multi-band signal through a wireless channel; And
And a network controller for calculating a usage amount for each frequency band, transmitting information to the satellite communication terminals, and allocating a frequency requested by the satellite communication terminals,
The network controller includes:
A route selection device for selecting a link according to a frequency usage amount, for calculating a frequency usage amount for each frequency band corresponding to a network load to provide information to satellite communication terminals, allocating a frequency requested by satellite communication terminals to the MF-TDMA / .

The method according to claim 1,
Further comprising a satellite repeater that performs relaying of the communication signal in the space, and selects the link according to the frequency usage amount.

3. The method of claim 2,
Wherein the packet path controller comprises:
And determines a transmission / reception path of traffic data in consideration of a usage amount of each frequency band received from the network controller and a signal attenuation in a frequency band in which rainfall damping is severe, and selects a link according to the frequency usage amount.

The method according to claim 1,
Wherein the modems in the respective frequency bands include:
Wherein the modem of the frequency band in which the rain attenuation is significant among the modems of each frequency band measures the signal attenuation due to the rain and provides the signal path attenuation information to the packet path controller so that the packet path controller can consider the path selection, To select a link according to the route.

The method according to claim 1,
The multi-
A path selection device for selecting a link according to a frequency usage amount, comprising a simultaneous multi-band single antenna for transmitting / receiving signals of multiple frequency bands or an antenna for each frequency band.

delete

A method for selecting a link according to a network load for each frequency band of satellite communication,
Transmitting a usage amount for each frequency band to all satellite communication terminals by a network controller;
A step in which data traffic flows into a satellite communication terminal;
Determining whether rain attenuation has occurred in the satellite communication terminal;
Transmitting data traffic to a modem having a low rainfall attenuation when a rain attenuation occurs in the satellite communication terminal;
Transmitting data traffic to a modem of a band with a small frequency usage considering a usage amount of each frequency band received from the network controller when a rain attenuation has not occurred in the satellite communication terminal;
Requesting the modem of the selected band to allocate the frequency of the corresponding band to the network controller in consideration of the rainfall attenuation and the frequency usage amount;
Allocating the frequency requested by the network controller according to the MF-TDMA / DAMA scheme and updating the bandwidth usage per band; And
And transmitting and receiving data traffic by the satellite communication terminal at the allocated frequency, wherein the link is selected according to the network load per frequency band.