KR101349228B1 - System and method for providing service in a satellite communication system - Google Patents

Abstract

The present invention relates to a service providing system and method for providing a communication service to a multi service area and users by efficiently using limited resources and power in a satellite communication system having a multi service area and a plurality of users. Receiving a service request signal from the terminals present in the service area to receive the service, calculating the total traffic amount in the service area by using the service request signal, and covering the calculated total traffic amount Forming a hierarchical multi beam providing services to the terminals, allocating resources and power to the formed hierarchical multi beams, and assigning allocation information of the allocated resources and power to the terminals After transmitting, the terminal through the formed hierarchical multi beam with the allocated resource and power To provide services.

Description

System and method for providing service in a satellite communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite communication system. In particular, a service for providing a communication service to a multi service area and users by efficiently using limited resources and power in a satellite communication system including a multi service area and a plurality of users. A provisioning system and method are provided.

The present invention is derived from the research conducted as part of the IT source technology development of the Korea Communications Commission (Task Management No .: 2008-F-010-02, Title: IMT-Advanced satellite access technology development (standardized connection)).

In the next generation communication system, active researches are being conducted to provide users with services of various quality of service (QoS: QoS) having high transmission speeds. In the current satellite communication system proposed as an example of such a next-generation communication system, the satellite communication system provides a service to a multi service area in which a plurality of service areas are implemented, and a plurality of users existing in the multi service area, that is, Terminals are provided with services having high speed and various QoS provided from the satellite communication system.

In the current satellite communication system, methods for stably providing a large capacity service having a variety of high-speed QoS to terminals existing in a multi-service area through limited resources available for providing a service have been proposed. In particular, the satellite communication system increases the total capacity of the satellite communication system when providing a service through a limited resource, and transmits the signal transmission efficiency of the satellite communication system, for example, when the signal is transmitted to the available power of the limited satellite communication system. In order to increase the effective isotropic radiated power (EIRP), a multi-beam based service provision method has been proposed. The satellite communication system providing a service based on the multi-beam obtains a diversity gain when providing a service to terminals existing in a multi-service area, and the terminals can receive the service more stably through the diversity gain. have.

However, as described above, when the satellite communication system provides a service to a plurality of terminals existing in the multi service area based on the multi beam, not only interference occurs between service areas implementing the multi service area. Interference occurs between terminals existing in the multi-service area. In particular, when a satellite communication system transmits a signal through a multi-beam to provide a service, a large interference occurs in terminals existing in a boundary area between the multi-beams, and in order to minimize such interference, for each service area and for each terminal. Or, a method of dividing a limited resource for each multi-beam, for example, by dividing a frequency has been proposed, but this has a problem in that the utilization efficiency of limited resources is degraded.

In addition, current users are required to provide a large amount of high-speed service, for example, to provide a high-definition multimedia service, and in particular, as the demand for providing such a large amount of high-speed service increases, the satellite communication system is required by users, such as user traffic demand. In accordance with the above circumstances, a large-capacity, high-speed service should be provided through broadband. However, currently available resources, such as allocable frequency bandwidth, for satellite service by the satellite communication system are limited as described above, and thus, a scheme for providing a large capacity and high speed service using the limited allocable bandwidth to the maximum. This is necessary.

In addition, when the satellite communication system provides a large-capacity high-speed service based on a multi-beam with a limited allocable frequency bandwidth, interference occurring in a multi-service area and users, particularly interference occurring in a boundary area of the multi-beam. It is necessary to provide a large-capacity high-speed service by minimizing the number of points, maximize the resource use efficiency when providing the service, and stably provide a large-capacity high-speed service by maximizing the power use efficiency of the satellite communication system.

Accordingly, an object of the present invention is to provide a service providing system and method for providing a communication service in a satellite communication system.

Another object of the present invention is to provide a service providing system and method for providing a service based on a multi-beam to a plurality of users existing in a multi-service area in a satellite communication system.

Another object of the present invention is to provide a service providing system and method for providing a service by minimizing interference occurring in a multi-service area and a plurality of users when providing a large-capacity high-speed service based on a multi-beam in a satellite communication system. In providing.

In addition, another object of the present invention is to provide a service providing system and method for stably providing a large capacity high speed service through limited resources by minimizing interference between beam boundary regions of a multi-beam in a satellite communication system.

In addition, another object of the present invention is to provide a service providing system and method for minimizing multi-beam interference by maximizing use of an assignable frequency bandwidth limited through multi-beams in a satellite communication system.

Another object of the present invention is to provide a service providing system and method for reducing power consumption of a system by providing a service through multiple beams of various coverage sizes in a satellite communication system.

According to an aspect of the present invention, there is provided a method of providing a service in a satellite communication system, the method comprising: receiving a service request signal from terminals which are present in a service area and are intended to receive a service; Calculating a total traffic amount in the service area by using the service request signal; Forming a hierarchical multi beam providing a service to the terminals by covering the calculated total traffic amount; And allocating resources and power to the formed hierarchical multi-beams, transmitting allocation information of the allocated resources and powers to the terminals, and then, through the formed hierarchical multi-beams using the allocated resources and powers. Providing a service to the terminals.

A system of the present invention for achieving the above objects, in a service providing system in a satellite communication system, exists in a service area, and in one of a first communication method, a terrestrial auxiliary device or a second communication method via a network. A plurality of terminals connected to the satellite communication system to receive a service; And receiving a service request signal from terminals wishing to receive a service in the service area, calculating a total traffic amount in the service area by using the service request signal, and covering the calculated total traffic amount. And a satellite base station that provides a service to the service area through a hierarchical multi beam.

According to the present invention, when a satellite communication system provides a service based on a multi-beam, a beam generated in a multi-service area and a plurality of users by providing a communication service by dividing a beam center area and a beam boundary area by a multi-beam The service can be provided stably by minimizing interference. In addition, the present invention provides a service by dividing a beam center region and a beam boundary region in order to minimize beam interference when the satellite communication system provides a service through a limited resource, thereby minimizing the use of limited resources. Maximize the efficiency of using resources. In addition, according to the present invention, the satellite communication system may provide a service through beams corresponding to the beam center region and the beam boundary region, thereby reducing power consumption of the system, thereby improving power usage efficiency.

1 is a view schematically showing the structure of a service providing system in a satellite communication system according to an embodiment of the present invention.
2 schematically illustrates a hierarchical multi-beam pattern of a satellite communication system according to an embodiment of the present invention.
3 schematically illustrates another hierarchical multi-beam pattern of a satellite communication system according to an embodiment of the present invention.
4 schematically illustrates another hierarchical multi-beam pattern of a satellite communication system according to an embodiment of the present invention.
5 schematically illustrates another hierarchical multi-beam pattern of a satellite communication system according to an embodiment of the present invention.
6 schematically illustrates another hierarchical multi-beam pattern of a satellite communication system according to an embodiment of the present invention.
FIG. 7 schematically illustrates another hierarchical multi-beam pattern of a satellite communication system according to an embodiment of the present invention. FIG.
8 is a diagram schematically illustrating a channel structure of a satellite communication system according to an embodiment of the present invention.
9 is a diagram schematically illustrating a frame structure of a satellite communication system according to an embodiment of the present invention.
10 is a diagram schematically illustrating a service providing process in a satellite communication system according to an exemplary embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, only parts necessary for understanding the operation according to the present invention will be described, and the description of other parts will be omitted so as not to disturb the gist of the present invention.

The present invention proposes a service providing system and method for providing a communication service in a satellite communication system. An embodiment of the present invention proposes a system and method for providing a communication service through a hierarchical multi beam in order to improve efficiency of using limited frequency resources and power available when providing a communication service. In addition, in an embodiment of the present invention, a satellite communication system provides a service to a plurality of users existing in a multi service area, that is, a terminal in a multi service area, implemented in a plurality of service areas based on a multi beam. We propose a service providing system and method. In an embodiment of the present invention to be described below, the satellite communication system will be described based on providing a service through a multi-beam, but the service providing system and method proposed by the present invention can be applied to other wireless communication systems.

In addition, in an embodiment of the present invention, various coverage sizes (eg, various coverage sizes) may be used to satisfy various needs of a plurality of users existing in a multi-service area, that is, various user traffic requirements, while improving frequency usage and power efficiency of the satellite communication system. Provides a communication service by forming a multi-beam having a coverage size). In other words, in the embodiment of the present invention, the satellite communication system forms multi-beams having various coverage sizes, that is, hierarchical multi-beams according to the amount of user traffic, and uses power in satellites through the hierarchical multi-beams formed. It provides communication service by adaptively satisfying user traffic requirements while improving efficiency.

In addition, in an embodiment of the present invention, a satellite communication system using a multi-beam is a multi-beam having a multi-beam having a different coverage size according to the amount of user traffic, for example, a low amount of user traffic or to provide a communication service In the area where the number of users is small, a layer having a large coverage size among hierarchical multi-beams, that is, a beam having the highest layer is formed, and a layer having a small coverage size is formed in an area where a large amount of user traffic or a large number of users is formed. To provide communication services to users. In the following embodiment of the present invention, hierarchical multi-beams used by the satellite communication system for convenience of description, the first beam of the highest layer having the largest coverage size, for example, the global beam, the first beam A second beam having a smaller coverage size, such as a regional beam, and a lowermost layer of the third beam having a smallest coverage size, such as a spot beam, will be described. As described above, although the hierarchical multi-beams are described based on three multi-beams, two or more multi-beams may be formed according to the communication environment and the coverage of the service area to provide a communication service. It may be.

Here, the satellite base station for providing a communication service in the satellite communication system according to an embodiment of the present invention, a layer of a beam that is used to provide a communication service to a plurality of users, that is, a terminal in a multi-service area, that is, a terminal In order to determine whether coverage should be formed, the distribution of traffic and the amount of traffic to be provided with the communication service are monitored in the entire coverage. The terminal existing in the multi-service area transmits a service request signal for requesting a communication service to the satellite base station through a spot beam uplink covering the area where the terminal is located, and transmits traffic information requested by the terminal itself. It is included in the service request signal and transmitted to the satellite base station.

In addition, in the satellite communication system according to an embodiment of the present invention, the satellite base station calculates the number of users and the amount of traffic required to receive a communication service for each layer beam. The satellite base station compares the capacity of the global beam with the amount of traffic required for the beam having the largest coverage size, for example, the global beam, and if the capacity does not exceed the capacity of the global beam as a result of the comparison. Provides a communication service by performing communication through a global beam, and when the comparison results in exceeding the capacity of the global beam, compares the required traffic amount with the capacity of the regional beam, and as a result of the comparison, does not exceed the capacity of the regional beam. If not, a communication service is provided by performing communication through the terminal beam. When the capacity of the comparison beam is exceeded as a result of the comparison, a communication service is provided by performing communication through a spot beam.

In the embodiment of the present invention, as described above, for the convenience of description, as the hierarchical multi-beams are the global beams, the regional beams, and the spot beams, the consideration between the required traffic amount and the capacity of the hierarchical multi-beams is considered global. Consider only beams, regional beams, and spot beams, but if the hierarchical multi-beams have a greater number of different coverage sizes, that is, the amount of traffic and layer required for multi-beams of more than three layers Consideration between capacities of enemy multi-beams is considered in order of coverage size.

In the embodiment of the present invention, when providing a communication service using a hierarchical multi-beam, the satellite communication system will be referred to as a quality of service (QoS) required by a user of a beam of each layer. ), And also allocates to maximize the efficiency of use of frequency resources and power available in the satellite communication system, and transmits the resource and power allocation information in the hierarchical multi-beam to a terminal attempting communication.

At this time, in the embodiment of the present invention, in order to reuse frequencies between adjacent beams having different coverage sizes in the hierarchical multi-beams as described above, first, the beam frequency resources of the smallest coverage size beams, for example, spot beams, are used for the satellite communication. It is allocated to correspond to the frequency reuse factor (operation factor) used in the system, and provides a communication service by allocating a beam having a large coverage size so as not to use a frequency resource used by a beam having a small coverage size. In addition, in an embodiment of the present invention, for reusing frequencies between adjacent beams having different coverage sizes, beams having a large coverage size form a multi-beam that does not overlap each other, and the frequency reuse coefficient is 1 in the multi-beams thus formed. Frequency resources other than the frequency resources allocated to the beams having the small coverage size are reused with the frequency reuse factor 1.

In addition, according to an embodiment of the present invention, when the satellite communication system provides a communication service through the multi-beam, when the signal is transmitted by time multiplexing to the terminal existing in the beam center region and the beam boundary region by the multi-beam In case of frequency multiplexing a signal transmission section to a terminal existing in the beam center region, and transmitting a signal by frequency multiplexing to the terminal existing in the beam center region and the beam boundary region, As a device for relaying signals between terminals, the terrestrial auxiliary apparatus transmits a signal to the terminal using the same subcarrier group in the same frequency band as the satellite base station, and at this time, the signal transmitted by the satellite base station and the terminal Does not interfere with

In addition, according to an embodiment of the present invention, a satellite communication system using a frequency reuse factor 1 is hierarchical based on an Orthogonal Frequency Division Multiple Access (OFDMA) scheme. In the case of providing a communication service by forming a multi-beam, the frequency reuse coefficient 1 is used in the beam center region, and the group of the plurality of frequency bands is partially reused regardless of beams of different layers in the beam edge region. Here, the satellite communication system separates a group of frequency bands used in beams of different layers in the beam edge region, and then uses a group of one frequency band as a frequency reuse factor 1 in a beam having a large coverage size. Beams with small coverage sizes allow partial reuse of the remaining groups of frequency bands.

Here, an example of a satellite communication system according to an embodiment of the present invention to be described later, a ground assist device (CTC: Complementary Terrestrial Component (CTC), such as a repeater, a Complementary Ground Component (CGC), AnTC (Ancillary Terrestrial Component) A satellite communication system to be used, a satellite digital multimedia broadcasting (DMB) system or a digital video broadcasting-satellite services to handhelds (DVB-SH) system for providing a broadcast service, and voice and data communication services in urban and off-campus locations. Mobile Satellite Services (MSS) systems are referred to as MSS (Mobile Satellite Ventures) and Terresstar's terrestrial integrated satellite system.

The satellite DMB system is a system that enables vehicle, fixed and portable reception of high-quality audio and multimedia signals by using a ground network using a co-channel repeater together with satellites. Both are optimized for the 2630 to 2655 MHz band. The satellite DMB system includes a feeder link earth station, a broadcast satellite, two types of terrestrial repeaters, and a terminal that is a receiver (vehicle, fixed, portable). In such a satellite DMB system, a transmission signal is transmitted to a satellite through a feeder earth station, and an uplink is used by a band for fixed satellite service (FSS) (for example, 14 GHz). do. The received signal is converted from the satellite to the 2.6 GHz band and then amplified to a predetermined size through an amplifier in the satellite repeater and broadcasted to the service area. A terminal that wants to receive a broadcast service from the satellite DMB system receives a signal through a small antenna having a low directionality, and in order to receive the signal, an effective isotropic radiated power (EIRP) of a sufficient size is set by a satellite transmitting a broadcast signal. As effective Isotropic Radiated Power (hereinafter referred to as "EIRP") is required, satellite DMB systems include large transmit antennas and high power repeaters. In addition, the satellite DMB system includes a repeater that retransmits the satellite signal to overcome the obstacles and shadowing problems of direct path from the satellite in signal propagation in the 2.6 GHz band. Here, the repeater is in charge of a portion covered by a band obstruction such as a building, and is divided into a direct amplification repeater and a frequency change repeater. The direct amplification repeater simply amplifies the broadcast signal of the 2.6 GHz band received from the satellite, and uses a low gain amplifier to avoid unnecessary divergence due to signal interference generated between the receiving and transmitting antennas. It covers a narrow area up to 500m based on (LoS: Line of Sight, hereinafter referred to as 'LoS'). In addition, the frequency conversion repeater is responsible for a wide area up to 3km based on LoS, and transmits the received 2.6GHz band signal to another frequency band (for example, 11GHz). In a satellite DMB system in such an environment, multipath fading occurs in which two or more signals are received, and code division multiplex (CDM: CDM) for stable reception of such multipath fading signals occurs. Rake receiver using the method) is used.

In addition, the DVB-SH system provides a communication service through satellite in nationwide coverage, provides a communication service using CGC in indoor environment and terrestrial coverage, and digital video broadcasting-handheld (DVB-H). Mobile TV service is provided in the 15MHz bandwidth of the S-band. Here, the DVB-SH system uses a band close to the terrestrial International Mobile Telecommunications (IMT) band of the S band, so that it is easy to integrate with the IMT terrestrial sector and to easily reuse the network with the terrestrial network. Reduce cost In particular, the DVB-SH system considers a hybrid broadcasting structure with the terrestrial network, and solves the signal interference problem between the satellite and the CGC and efficiently uses frequencies in one CGC cell in one satellite spot beam. The frequency reuse factor is set to 1 for a satellite spot beam, and the frequency reuse factor is set to 3 for a satellite spot beam. As a result, it broadcasts nine TV channels for nationwide coverage via satellite spot beams, and 27 channels with terrestrial repeaters in urban or indoor environments.

In addition, the terrestrial satellite integrated system using the ATC of the MSV and Terrestar is a satellite communication system based on geostationary orbit (GEO), which is connected to the Internet and voice in the L and S bands. Provides a ubiquitous wireless wide area communication service such as a call to the terminal. The terrestrial satellite integrated system provides a voice or high-speed packet service through an ATC, that is, a terrestrial network, using a hybrid wireless network structure that combines satellite / ATC, and that is not covered by the ATC. In the region, satellite services are provided. Here, the ATC minimizes the complexity of the terminal existing on the ground by using a radio interface similar to the satellite and allows the satellite communication service to be provided.

Satellite communication system according to an embodiment of the present invention to be described later, may be a personal portable mobile satellite communication system, and provides a communication service through a satellite in rural or offshore areas where LoS is secured using a ground assist device, In urban or indoor environments where no signal is available, ground services provide communication services. In this case, the satellite communication system improves the spectrum use efficiency and power use efficiency of the hierarchical multi-beam in consideration of a communication environment providing a communication service using a terrestrial auxiliary device and a communication environment providing a communication service through a satellite. In addition, it provides a stable communication service in accordance with the traffic requirements of each user who wants to receive a communication service in a multi-service area.

In addition, the satellite communication system according to an embodiment of the present invention, by monitoring the instantaneous traffic requirements of the users existing in the entire satellite coverage to form a multi-beam having a coverage size corresponding to the traffic requirements, and thus with various coverage sizes Provides a communication service by effectively reusing the frequency between the formed multi-beams. In the embodiment of the present invention to be described later, the satellite communication system has a commonality with the terrestrial system, which is a communication system of various methods that exist on the ground, the terrestrial system connection scheme, for example, OFDMA, code division multiple access (CDMA: Code Transmit and receive signals with all terrestrial systems regardless of access standards, such as Division Multiple Access (hereinafter referred to as "CDMA") and Time Division Multiple Access (TDMA). It is possible to provide a communication service using the multi-spot beam. Then, the service providing system in the satellite communication system according to an embodiment of the present invention will be described in more detail with reference to FIG. 1.

1 is a diagram schematically illustrating a structure of a service providing system in a satellite communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a service providing system in the satellite communication system includes a satellite 102 which is a satellite base station providing a communication service using a hierarchical multi-beam, and exists in an out-of-region area to provide a communication service from the satellite 102. Terminal 1 (170) provided, the gateway 104 for connecting the signal transmission and reception between the satellite 102 and the terrestrial system, included in the terrestrial system for transmitting and receiving signals with the satellite 102 via the gateway 104 A core network 106, a connection network 110 connected to the core network 106 to provide a communication service, and communication to other terminals included in the terrestrial system connected to the core network 106. A base station (BS) (hereinafter referred to as a BS) 108 that provides a service and performs a control station function for controlling a base station or a base station, and the terrestrial auxiliary device of the satellite 102. CGC 132 which provides communication services to terminals existing in the service area 130 of the downtown area, and the service area 105 at the boundary of the outlying area and the downtown area to provide communication service to the satellite 102. It includes terminals provided.

Here, in the embodiment of the present invention, the satellite 102 as the satellite base station, the satellite 102 as the satellite base station, supports the first communication scheme by direct communication between the terminals existing in the service area and the satellite communication system. And a GEO satellite transmitting a signal through a hierarchical multi-beam, for example, a global beam, a regional beam, and a spot beam, and for convenience of description, a case in which only one satellite is present will be described as an example. In addition, a plurality of GEO satellites as well as other types of satellites may exist to provide communication services. Each of these satellites provides a communication service to terminals using a mono or multi spot beam. In addition, in an embodiment of the present invention to be described later, for convenience of description, the satellite communication system forms a hierarchical multi-beam, allocates resources and powers of the hierarchical multi-beams to the terminals existing in the service area. Although described as providing a communication service, a satellite base station, such as satellite 102, of the satellite communication system performs the formation of hierarchical multi-beams and resource and power allocation.

In other words, the satellite base station of the satellite communication system monitors the distribution of the users, that is, the terminals and the traffic amount of each terminal in the service area, and measures the coverage size corresponding to the distribution and the traffic amount of the terminals according to the monitoring. Form hierarchical multi-beams for each coverage size to cover, and allocate resources and power corresponding to hierarchical multi-beams to provide communication services to terminals by transmitting data traffic through the formed hierarchical multi-beams. After that, the communication service is provided to the terminals in a hierarchical multi-beam through the allocated resources and power. In this case, the satellite base station minimizes hierarchical multi-beam interference when providing a communication service while satisfying QoS, and also maximizes frequency use efficiency and power use efficiency. Hereinafter, for convenience of description, the satellite communication system will be collectively described as performing the operation of the satellite base station.

In addition, the area where the terminals are located may be one spot area or a plurality of spot group areas by roaming of the terminal, and the terminal included in the terrestrial system includes at least one of the gateways 104 connected to at least one satellite. Connected to the network to receive communication services. In this case, the satellite 102 communicates through an interface corresponding to a terrestrial system, communication devices included in the terrestrial system, and terrestrial auxiliary devices and a connection standard in the terrestrial system. In the embodiment of the present invention, for convenience of description, it is assumed that the satellite 102 communicates with a terrestrial system and other devices using an OFDMA-based satellite radio interface. .

In addition, the gateway 104 may be a centralized gateway or a gateway of a group of gateways geographically distributed according to the requirements of the satellite communication system or the operator of the satellite communication system. do. In addition, the gateway 104 is connected to the BS 108 which is a subsystem connected to the core network 106 or the access network 110 to transmit and receive signals. Here, the BS 108 performs the same functions of the base station and the control station used in the terrestrial network as described above, and also exists inside the gateway 104 or externally as shown in FIG. 1. exist.

In addition, the satellite communication system uses a satellite (eg, a ground assist device) such as CGC 132 for coverage continuity in a shadow area where signal transmission is caused by a building, a mountain, etc. in a service area 130 of an urban area. The same frequency as that of 102 is reused, and at this time, the satellite signal of the satellite 102 is amplified and transmitted to the terminals existing in the service area 130 through the reused frequency. That is, the satellite communication system may provide a broadcast service or a multimedia broadcast multicast service (MBMS) to terminals included in the terrestrial system as well as out-of-town and urban areas through a satellite 102 or a ground assist device. MBMS ').

In this case, the satellite communication system provides MBMS through satellite 102 in national coverage such as rural areas or rural areas where LoS is secured, and urban areas or indoor environments where satellite signals are not secured because buildings or buildings exist. In the service area 130, the MBMS is provided through a terrestrial assistance device such as the CGC 132. Here, the repeater that performs the function of relaying satellite signals, such as the terrestrial auxiliary device, does not provide voice and data communication services but simply performs the function of relaying, thus considering only downlink transmission, and needs information for providing MBMS. In case it transmits over the ground network of the ground system.

In addition, when the satellite communication system provides a voice and data communication service through a limited frequency resource, it is difficult to provide a communication service to all terminals existing in a multi-service area through a beam having very large coverage. Voice and data communication services are provided through a beam to a terminal existing in an area not covered by the terrestrial network in the service area. In addition, the terrestrial auxiliary apparatus is upward in order to provide voice and data communication services or MBMS to terminals not covered by the terrestrial network in the service area and not present in an area where satellite signals are not secured, that is, a coverage area by a beam. The link signal is transmitted to the satellite 102.

In the satellite communication system, a terminal existing in an area not covered by the terrestrial network receives a communication service from the satellite 102 as described above, and when the terminal enters coverage of the terrestrial network, the transmission efficiency is increased. In order to receive the communication service from the terrestrial network, which is superior to), a vertical handover is performed between the satellite 102 and the terrestrial network. In this case, the terminal may transmit and receive both signals from the terrestrial network and the satellite 102, and if the terrestrial network and the satellite 102 transmit and receive signals in different connection standards, to reduce the overhead (overhead) As described above, a signal is transmitted and received with the terrestrial network and the satellite 102 using an OFDMA-based satellite air interface.

In addition, in the satellite communication system, the satellite 102 uses a multiple input multi output (MIMO) method in which one satellite uses a polarization characteristic of an antenna. Form a hierarchical multi-beam, or a plurality of satellites form a hierarchical multi-beam to transmit a signal to provide a communication service, thereby increasing data transmission capacity and improving data reception performance. In addition, the satellite communication system is a space diver for the slow-fading effect of the satellite 102 through cooperative communication and ad-hoc network formation between terminals using a terrestrial auxiliary device. It gains city gain and improves total system throughput by efficiently using limited frequency resources through hierarchical multi-beams. In addition, the satellite communication system improves the power usage efficiency of the satellite 102 by using a hierarchical multi-beam pattern rather than a fixed beam pattern, and adaptively provides a communication service according to user requirements. In addition, it minimizes interference between adjacent beams in hierarchical multi-beams and improves frequency reuse efficiency. Next, the hierarchical multi-beam pattern of the satellite communication system according to an embodiment of the present invention will be described in more detail with reference to FIG. 2.

2 is a diagram schematically illustrating a hierarchical multi-beam pattern of a satellite communication system according to an exemplary embodiment of the present invention.

2, the satellite communication system includes a plurality of hierarchical multi-beams, that is, a global beam 200 having the largest coverage size, a coverage size smaller than the global beam 200, and the global beam 200. A plurality of beams implemented with a plurality of beams to cover a coverage size of the plurality of beams, and a plurality of beams having the smallest coverage size and covering the coverage sizes of the global beam 200 and the multi-regional beams 210. To form a multi-spot beam 220 implemented as. Herein, in the embodiment of the present invention, as described above, the hierarchical multi-beam will be described based on three multi-beams for the convenience of description. However, two or more plurality of multi-beams may be provided depending on the communication environment and the coverage of the service area. Multi-beams may be formed to provide a communication service.

The multi-spot beam 220 having the smallest coverage size among the hierarchical multi-beams most efficiently reuses limited frequency resources, and has a high beam antenna gain, resulting in high EIRP compared to other metrology multi-beams. Have Therefore, the satellite communication system provides a communication service through a multi-spot beam 220 having the smallest coverage size in an area where a large number of terminals requesting high-speed traffic or receiving communication service to a service area having a high data processing demand. To provide.

Here, the satellite communication system should allocate and manage frequency resources corresponding to terminals to receive communication service through a plurality of multi-spot beams 220 corresponding to each service area, and thus have the smallest coverage size. When providing a communication service through the multi-spot beam 220, on-board processing for service provision becomes complicated, and resources between terminals are managed by managing frequency resources independently for each multi-spot beam 220. And adaptive allocation may be difficult in allocating power.

On the other hand, when the satellite communication system provides a communication service through a beam having a larger coverage size than the multi-spot beam 220, for example, the global beam 200, the frequency reuse efficiency and the transmission EIRP efficiency are deteriorated. If the number of terminals is small and the amount of traffic is small when resource and power are allocated due to the large coverage size, the resources are allocated to satisfy the requirements of each terminal, for example, user traffic requirements, and the power consumption is minimized. The power usage of the satellite communication system is improved.

That is, in the satellite communication system according to the embodiment of the present invention, the number of traffics and the amount of traffic in the service area are checked in the service area where the amount of user traffic is low or the number of terminals that are intended to receive communication service is as described above. A service providing a communication service by forming a global beam 200 or a multi-regional beam 210 having a large coverage size among the same hierarchical multi beams, and has a large amount of user traffic or a large number of terminals to receive communication services. In the area, a multi-spot beam 220 having a small coverage size is formed to provide a communication service. Next, another hierarchical multi-beam pattern of the satellite communication system according to an embodiment of the present invention will be described in more detail with reference to FIG. 3.

3 is a diagram schematically illustrating another hierarchical multi-beam pattern of a satellite communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the satellite communication system forms a plurality of hierarchical multi-beams, for example, a global beam, a multi-regional beam, and a multi-spot beam, as described above with reference to FIG. 2. The description of the provision of the communication service through the global beam by the satellite communication system will be omitted, and the description will be mainly focused on providing the communication service through the multi-regional beam 300 and the multi-spot beam 350.

In this case, the satellite communication system uses a multi-regional beam 300 in a service area such as a low-traffic traffic or a small number of terminals to be provided with a communication service, for example, an area of dawn, a rural area, and the sea. Provides communication services, thereby simplifying on-board processing of satellites in satellite communication systems and minimizing power consumption to allocate resources and power. In addition, the satellite communication system includes a multi-spot beam having the smallest coverage size in order to increase overall system throughput in a service area such as an urban area, for example, when there is a large amount of traffic or a large number of terminals to be provided with a communication service. Provide communication service through 350. Next, the hierarchical multi-beam pattern for frequency reuse in adjacent beams having different coverage sizes will be described in more detail with reference to FIG. 4.

4 is a diagram schematically illustrating another hierarchical multi-beam pattern of a satellite communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the satellite communication system forms a plurality of hierarchical multi-beams, for example, a global beam, a multi-regional beam, and a multi-spot beam, as described above with reference to FIG. 2. The description of the provision of the communication service through the global beam is omitted in the satellite communication system, and the description will be mainly focused on providing the communication service through the multi-regional beams 402, 403, 404, 406, 408 and the multi-spot beams 412, 414, 416, 418. Here, the satellite communication system provides a communication service by reusing a frequency between adjacent beams with a frequency reuse between adjacent beams having different coverage sizes, for example, a frequency reuse factor of 3.

In more detail, the satellite communication system may allocate a frequency of the multi-spot beams 412, 414, 416, 418 so that the frequency reuse factor is 3, for example, a multi-spot beam using a frequency band having a center frequency fc of 1. 412, a multi spot beam 414 using a frequency band with a center frequency of 2, a multi spot beam 416 using a frequency band with a center frequency of 3, and a frequency band using a center frequency of 2 or 3 Each frequency is assigned to be a multi-spot beam 418. In addition, the satellite communication system allocates frequencies in a manner that does not use the frequencies used by the adjacent multi-spot beams 412, 414, 416, 418 such that the multi-regional beams 402, 403, 404, 406, 408 do not interfere with the adjacent multi-spot beams 412, 414, 416, 418. Multi-regional beam 402 using a frequency band with a center frequency of 1, multi-regional beam 403 using a frequency band with a center frequency of 2, multi-regional beam using a frequency band with a center frequency of 3 404, the multi-regional beam 406 using a frequency band with a center frequency of 1 or 3, and the multi-regional beam 408 using a frequency band with a center frequency of 1, 2 or 3 Assign them to reuse frequencies.

Accordingly, the satellite communication system allocates frequencies having different center frequencies between adjacent beams with different coverage sizes so that the multi-regional beams 402, 403, 404, 406, 408 are sparsely arranged in the service area to adjacent multi-regional beams. Reduces interference between the multi-regional beams 402, 403, 404, 406, 408 and the multi-spot beams 412, 414, 416, 418 by not using frequencies having the same center frequency as the adjacent multi-spot beams 412, 414, 416, 418. Reduce interference. In addition, the satellite communication system reduces the interference between adjacent beams by reducing the EIRP as there are only the multi-spot beams due to the presence of the multi-region beams 402, 403, 404, 406 and 408 adjacent to the multi-spot beams 412, 414, 416, 418. Then, another hierarchical multi-beam pattern for frequency reuse in adjacent beams having different coverage sizes will be described in more detail with reference to FIG. 5.

5 is a diagram schematically illustrating another hierarchical multi-beam pattern of a satellite communication system according to an embodiment of the present invention.

Referring to FIG. 5, the satellite communication system forms a plurality of hierarchical multi-beams, for example, a global beam, a multi-regional beam, and a multi-spot beam, as described above with reference to FIG. 2. The description of the provision of the communication service through the global beam in the satellite communication system will be omitted, and the description will be mainly given on providing the communication service through the multi-regional beam 502 and the multi-spot beams 504, 506, and 508. In this satellite communication system, frequency reuse between adjacent beams having different coverage sizes, for example, the multi-regional beam 502 reuses a frequency with a frequency reuse factor of 1 to provide a communication service, and the multi-spot beams 504, 506, and 508 Provides communication service by reusing frequency with frequency reuse factor 3.

In more detail, in the satellite communication system, the multi-regional beams 502 are formed so as not to overlap each other when forming a hierarchical multi-beam, and then the multi-regional beams 502 are formed at the multi-spot beams 504, 506, and 508. Assign a frequency other than the frequency used to use as frequency reuse factor 1. Here, in the satellite communication system, a frequency band having a frequency other than the frequency used by the multi-spot beams 504, 506, and 508, for example, a center frequency of 4, is used as the frequency reuse factor 1 to provide a communication service. To allocate. In addition, the satellite communication system assigns frequencies of the multi-spot beams 504, 506, and 508 so that the frequency reuse coefficient is 3, for example, a multi-spot beam 504 using a frequency band having a center frequency of 1, and a center frequency of 2 The frequencies are respectively assigned to be the multi-spot beams 506 using the in-frequency band and the multi-spot beams 508 using the frequency band with a center frequency of three.

Accordingly, the satellite communication system minimizes the interference between the multi-regional beams and maximizes the frequency use efficiency as the multi-regional beams 502 do not overlap each other with a frequency reuse factor of 1. In addition, the satellite communication system, as the multi-regional beam 502 and the adjacent multi-spot beams (504, 506, 508) provides a communication service using a frequency having a different center frequency, the multi-regional beam 502 and Interference between the multi-spot beams 504, 506, 508 is minimized. Next, the hierarchical multi-beam pattern for reusing a subcarrier of a frequency band in the satellite communication system according to the embodiment of the present invention will be described in more detail with reference to FIG. 6.

6 is a diagram schematically illustrating another hierarchical multi-beam pattern of a satellite communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 6, the satellite communication system forms a plurality of hierarchical multi-beams, for example, a global beam, a multi-regional beam, and a multi-spot beam, as described above with reference to FIG. 2. The description of the provision of the communication service through the global beam is omitted in the satellite communication system, and the description will be mainly given on providing the communication service through the multi-regional beam 600, 680 and the multi-spot beam 605, 610, 615, 620, 625, 630, 635, 640, 645, 650, 660, 665, 670, 675. Here, the satellite communication system allocates a frequency to provide a communication service with a frequency reuse factor of 1 in the center region of each beam, that is, through all subcarriers (all) of available frequencies, and uses it in the edge region of each beam. Possible frequency is divided into subcarrier group 1 (SC1), subcarrier group 2 (SC2), and subcarrier group 3 (SC3) into a plurality of subcarrier groups, for example, three subcarrier groups, and interference between adjacent beams A frequency is allocated to provide a communication service through a predetermined subcarrier group among the divided subcarrier groups so as to be minimized.

In more detail, the satellite communication system allocates a terminal located in the center region of the multi-regional beams 600 and 680 to provide a communication service through all subcarriers 602 and 682 in an available frequency band, and provides a multi-spot. A terminal located in the center region of the beams 605, 610, 615, 620, 625, 630, 635, 640, 645, 650, 660, 665, 670, 675 is also allocated to provide communication services through all subcarriers 607, 612, 617, 622, 627, 632, 637, 642, 647, 652, 662, 667, 672, 677. In addition, the satellite communication system allocates a terminal located in the edge region of the multi-regional beams 600 and 680 to provide a communication service through subcarrier group 3 604 and subcarrier group 1 684. In addition, the satellite communication system includes subcarrier group 1 (614, 634, 644, 674), subcarrier group 2 (609, 619, 624, 639, 649, 664, 679), and subcarrier group 3 (629) through 629, respectively. Assign each to provide a service.

In this case, the satellite communication system allocates a frequency to provide a communication service through all subcarriers as described above in the center region of the multi-regional beam 600, 680 and the multi-spot beam 605, 610, 615, 620, 625, 630, 635, 640, 645, 650, 660, 665, 670, 675. This maximizes the frequency usage efficiency and minimizes interference between adjacent beams in all subcarriers assigned to the center region of each beam. The satellite communication system uses a frequency to provide a communication service through a subcarrier group not overlapping with a subcarrier group of an edge region of a beam adjacent to an edge region of a multi-regional beam 600,680 and a multi-spot beam 605,610,615,620,625,630,635,640,645,650,660,665,670,675. By assigning, interference between each adjacent beam is minimized. Next, with reference to FIG. 7, another hierarchical multi-beam pattern for subcarrier reuse of a frequency band will be described in more detail based on the OFDMA scheme of the satellite communication system.

7 is a diagram schematically illustrating another hierarchical multi-beam pattern of the satellite communication system according to an embodiment of the present invention.

Referring to FIG. 7, the satellite communication system forms a plurality of hierarchical multi-beams, for example, a global beam, a multi-regional beam, and a multi-spot beam, as described with reference to FIG. 2. The description of the provision of the communication service through the global beam is omitted by the satellite communication system, and the description will be mainly given on providing the communication service through the multi-regional beam 700, 780 and the multi-spot beam 705, 710, 715, 720, 725, 730, 735, 740, 745, 750, 760, 765, 770, 775. Here, the satellite communication system allocates a frequency to provide a communication service with a frequency reuse factor of 1 in the center region of each beam, that is, through all subcarriers (all) of available frequencies, and uses it in the edge region of each beam. The possible frequencies are divided into subcarrier groups 1 (SC1), subcarrier group 2 (SC2), subcarrier group 3 (SC3), and subcarrier group 4 (SC4) into a plurality of subcarrier groups, for example, three subcarrier groups. A frequency is allocated to provide a communication service through a predetermined subcarrier group among the divided subcarrier groups so that interference between adjacent beams is minimized.

In more detail, the satellite communication system allocates a terminal located in the center region of the multi-regional beams 700 and 780 to provide a communication service through all subcarriers 702 and 782 of available frequency bands, and provides a multi-spot. A terminal located in the center region of the beams 705, 710, 715, 720, 725, 730, 735, 740, 745, 750, 760, 765, 770, 775 is allocated to provide communication service through all subcarriers 707, 712, 717, 722, 727, 732, 737, 742, 747, 752, 762, 767, 772, 777. In addition, the satellite communication system allocates a terminal located in the edge region of the multi-regional beams 700 and 780 to provide a communication service through subcarrier group 4 (704 and 784). In addition, the satellite communication system includes subcarrier group 1 (714,734,744,774), subcarrier group 2 (709,719,724,739,749,764,779), and subcarrier group 3 (729,754,769) for the terminal located in the edge region of the multi-spot beam 705,710,715,720,725,730,735,740,745,750,760,765,770,775. Assign each to provide a service.

In this case, the satellite communication system allocates frequencies to the center regions of the multi-regional beams 700, 780 and the multi-spot beams 705, 710, 715, 720, 725, 730, 735, 740, 745, 750, 760, 765, 770, 775 as described above to provide a communication service through all subcarriers. This maximizes the frequency usage efficiency and minimizes interference between adjacent beams in all subcarriers assigned to the center region of each beam. The satellite communication system uses a frequency to provide a communication service through a subcarrier group not overlapping with a subcarrier group in an edge region of a beam adjacent to an edge region of a multi-region beam 700, 780 and a multi-spot beam 705, 710, 715, 720, 725, 730, 735, 740, 745, 750, 760, 765, 770, 775. By assigning, interference between each adjacent beam is minimized. In addition, the satellite communication system assigns an unused subcarrier group, ie, subcarrier group 4, to the edge region of the multi-regional beam 700,780 by using the unused subcarrier group 4 in the edge region of the multi-spot beam 705,710,715,720,725,730,735,740,745,750,760,765,770,775. 700, 780 and the interference with the adjacent multi-spot beams are minimized. In addition, the satellite communication system improves frequency usage efficiency by reusing the subcarrier group 4 as the frequency reuse factor 1 in the edge regions of the multi-regional beams 700 and 780 as described above. Then, the channel for transmitting the resource and power allocation information of the hierarchical multi-beam for providing a communication service by forming a hierarchical multi-beam as described above in the satellite communication system according to an embodiment of the present invention with reference to FIG. This will be described in more detail.

8 is a diagram schematically illustrating a channel structure of a satellite communication system according to an embodiment of the present invention.

Referring to FIG. 8, the satellite communication system forms a hierarchical multi-beam, for example, a global beam, a regional beam, and a multi-spot beam, as described above, and includes resources, such as FIG. 2, in the hierarchical multi-beam formed. As shown in FIG. 7, when a frequency is allocated and power of the formed hierarchical multi-beams is allocated to provide a communication service through the allocated frequency, the resource and power allocation information of the hierarchical multi-beams is controlled. It transmits to the terminals existing in the service area through the 810, 820, 830, and also transmits the data traffic to the terminals through the data channel 840 to transmit a communication service.

In more detail, the satellite communication system transmits the frequency allocation information and the power allocation information of the global beam to the terminals through the control channel 1 810 in the hierarchical multi-beam, and in the hierarchical multi-beam The frequency allocation information and the power allocation information of the regional beam are transmitted to the terminals through the control channel 2 (820), and the frequency allocation information and the power allocation information of the multi-spot beam in the hierarchical multi beam are controlled by the control channel 3 (830). And transmits to the terminals. The satellite communication system provides a communication service by transmitting data traffic to the terminals through the data channel 840 in the hierarchical multi-beam. Here, the control channels 810, 820, 830 are transmitted together through multiplexing of time, frequency, and sign like the data channel 840, and FIG. 5 shows the time multiplexed control channels 810, 820, 830 and data channel 840. Figure is shown.

In addition, after attempting to access an initial terminal through a multi-spot beam, terminals to which communication service is to be provided from the satellite communication system are connected, and then control channel 1 810 including global beam allocation information in the hierarchical multi-beam. If the resource allocation information is confirmed by the UE and the resource allocation information corresponding to the result of the check does not exist, the resource of the own channel in the control channel 2 820 including the allocation information of the regional beams in the hierarchical multi-beam Check the allocation information. If the allocation information does not exist as a result of the checking, the terminals check their resource allocation information in the control channel 3 830 including the allocation information of the multi-spot beam in the hierarchical multi-beam.

The terminal confirming the allocation information corresponding to itself from the control channels 810, 820, and 830 receives data traffic through the corresponding beam through the corresponding beam and receives the communication service using the identified allocation information. Next, the frame structure when providing a communication service through the hierarchical multi-beam of the satellite communication system according to an embodiment of the present invention will be described in more detail with reference to FIG. 9.

9 is a diagram schematically illustrating a frame structure of a satellite communication system according to an embodiment of the present invention. Here, FIG. 9 schematically illustrates a frame structure when the satellite communication system provides a communication service in a hierarchical multi-beam pattern for subcarrier reuse of a frequency band based on the OFDMA scheme as described with reference to FIG. 6. Drawing. In FIG. 9 to be described later, as described with reference to FIG. 6, a frequency band that can be used by the satellite communication system is divided into three subcarrier groups, namely, subcarrier group1, subcarrier group2, and subcarrier group3, thereby providing a hierarchical multi-beam. Although a case of allocating to an edge region will be described, the present invention can be similarly applied to other cases including the case of dividing into four subcarrier groups as described with reference to FIG. 7.

Referring to FIG. 9, the satellite communication system divides a time period of a predetermined frame, for example, frame 1 902 and frame 2 904 and hierarchies through all subcarrier regions 910 and 930 of the first time period. Allocate a communication service in the center region of the multi-beam, and divide the second time period into a plurality of subcarrier group regions, for example, subcarrier group 1 (SC1) regions 925 and 945, subcarrier group 2 (SC2) regions 920, 940, and subcarrier group 3 (SC3) regions 915, 935, and then allocate the communication service in the edge region of the hierarchical multi-beam through the divided subcarrier group regions 925, 945, 920, 940, 915, 935.

Here, the satellite communication system transmits data traffic to terminals existing in the center region of each beam using the subcarrier regions 910 and 930 of the first time period as the frequency reuse factor 1, and the subcarrier group area of the second time period. Through the fields 925, 945, 920, 940, 915, 935, data traffic is transmitted to the terminals by minimizing interference between adjacent beams in the edge region of each beam. Further, when the satellite communication system divides the subcarrier group into more than or less than three as described above, the satellite communication system divides the second time period into the corresponding subcarrier group region, and then the edge region of each beam. To provide communication services. In addition, the size of the subcarrier regions 910 and 930 in the first time period and the size of the subcarrier group regions 925, 945, 920, 940, 915 and 935 in the second time period are the amount of traffic in the center region and the edge region of the hierarchical multi-beam. In other words, the number of terminals existing in each region and the amount of traffic of each terminal are determined in correspondence. Then, the service providing operation through the hierarchical multi-beam in the satellite communication system according to an embodiment of the present invention will be described in more detail with reference to FIG. 10.

10 is a diagram schematically illustrating a service providing process in a satellite communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 10, in step 1010, when the terminals that are in a service area and want to receive a communication service access first through a multi-spot beam, the satellite communication system transmits / receives the number of terminals and the terminals to the terminals in step 1010. Check the amount of data traffic to do. In more detail, the satellite communication system monitors a distribution of users, that is, terminals, and traffic amount of each terminal, which is to receive a communication service in a service area. At this time, the terminals are a service request signal for requesting a communication service through uplink with a multi-spot beam having a coverage size covering the area where the terminal is currently located, that is, a communication service to be provided by accessing the satellite communication system. It transmits a service request signal including information about, for example, service type information for determining the amount of traffic of the terminal. The satellite communication system checks the number of terminals requesting a communication service through an uplink multi-spot beam, and also checks the amount of traffic for each uplink multi-spot beam.

Then, in step 1015, the satellite communication system calculates the required traffic volume required for the coverage for each multi-spot beam in the service area from the number of the identified terminals and the traffic amounts of the respective terminals, and calculates the calculated traffic volume. Compare the total traffic amount and the available capacity of the beam with the largest coverage size in the hierarchical multi-beam, for example, the global beam. In other words, the satellite communication system calculates the total number of traffic and the total amount of traffic to be provided with the communication service in each beam coverage for each multi-spot beam by using the signals transmitted by each terminal through uplink, The total traffic amount required for the global beam and the regional beam is calculated from beams having a larger coverage size than the multi-spot beam, that is, upper layer beams, based on the total traffic amount required from the spot beam. The traffic amount and the beam at the top layer are compared with the available capacity of the global beam.

As a result of the comparison in step 1015, if the total traffic amount is smaller than the available capacity of the global beam, that is, if the coverage according to the number of terminals existing in the service area and the traffic amount of each terminal is smaller than the coverage size of the global beam, In step 1020, the satellite communication system determines to provide a communication service to terminals existing within a service area using a global beam. That is, the satellite communication system provides a communication service by performing a communication through the global beam with all terminals existing in the service area since the calculated total traffic amount does not exceed the available capacity that can be provided through the global beam. do.

In operation 1025, the satellite communication system allocates resources and power to satisfy the QoS of each terminal receiving the communication service through the global beam, and maximize the frequency use efficiency with the minimum power in providing the communication service. In addition, the information on the allocated resource and power is transmitted through the control channel as described above to provide communication services to the terminals.

On the other hand, as a result of the comparison in step 1015, if the total traffic amount is larger than the available capacity of the global beam, that is, if the coverage according to the number of terminals existing in the service area and the traffic amount of each terminal is larger than the coverage size of the global beam In step 1030, the satellite communication system compares the total traffic amount with available capacity of a lower layer beam, that is, a regional beam, of the global beam. Here, the comparison between the total traffic amount and the available capacity of the regional beam is performed independently for each regional beam in the multi-regional beam.

When the total traffic amount is smaller than the available capacity of the terminal beam, the coverage according to the number of terminals existing in the service area and the traffic amount of each terminal is determined as a result of the comparison in step 1030. If it is smaller than the size, in step 1035, the satellite communication system determines the provision of the communication service to the terminals existing in the service area by the regional beams. That is, in the satellite communication system, since the calculated total traffic amount does not exceed the available capacity that can be provided through the terminal beam, the satellite communication system communicates with all terminals existing in the service area through the terminal beam. To provide.

In operation 1025, the satellite communication system allocates resources and power to satisfy the QoS of each terminal receiving the communication service through the regional beam and maximize the efficiency of using the frequency with the minimum power when providing the communication service. In addition, the information on the allocated resource and power is transmitted through the control channel as described above to provide communication services to the terminals.

Herein, the satellite communication system allocates frequencies having different center frequencies between adjacent multi-region beams to minimize interference between adjacent beams as described above, or assigns frequencies having different center frequencies from adjacent multi-spot beams. Assign. Further, the satellite communication system divides the usable frequency band into a plurality of subcarrier groups based on the OFDMA scheme, and then allocates all subcarriers of the usable frequency band to the center region of the regional beam and to the edge region. An unassigned subcarrier group is allocated to the edge region of the adjacent multi-spot beam among the divided subcarrier groups.

In addition, as a result of the comparison in step 1030, if the total traffic amount is larger than the available capacity of the regional beam, that is, the coverage according to the number of terminals existing in the service area and the traffic amount of each terminal is the coverage size of the regional beam. If greater, in step 1040, the satellite communication system determines to provide a communication service to terminals existing in a service area as a beam of a lower layer of the regional beam, that is, a multi-spot beam. That is, in the satellite communication system, the calculated total traffic amount does not exceed the available capacity that can be provided through the multi-spot beam, thereby communicating with all terminals existing in the service area through the multi-spot beam to provide a communication service. To provide.

In operation 1025, the satellite communication system allocates resources and power to satisfy the QoS of each terminal receiving the communication service through the multi-spot beam, and maximize the frequency use efficiency with the minimum power in providing the communication service. In addition, the information on the allocated resource and power is transmitted through the control channel as described above to provide communication services to the terminals.

Herein, the satellite communication system allocates frequencies having different center frequencies between adjacent multi-region beams to minimize interference between adjacent beams as described above, or assigns frequencies having different center frequencies from adjacent multi-spot beams. Assign. The satellite communication system divides the usable frequency band into a plurality of subcarrier groups based on the OFDMA scheme, and then allocates all the subcarriers of the usable frequency band to the center region of the multi-spot beam and to the edge region. An unassigned subcarrier group is allocated to the edge regions of the adjacent regional beams and the adjacent multi-spot beams among the divided subcarrier groups.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of the appended claims, as well as the appended claims.

Claims (21)

A service providing method in a satellite communication system,
Receiving a service request signal from terminals present in a service area to receive a service;
Calculating a total traffic amount in the service area by using the service request signal;
Forming a hierarchical multi beam providing a service to the terminals by covering the calculated total traffic amount; And
After allocating resources and power to the hierarchical multi-beams, and transmitting the allocated resource and power allocation information to the terminals, service the terminals through the hierarchical multi-beams with the allocated resources and powers. Providing;
Comparing the calculated total trapping amount with the available capacity of the hierarchical multi-beams in the service area, a multi-layer of a predetermined layer is formed in which the coverage size of the hierarchical multi-beams covers the calculated total trapping amount. Characterized in that the service providing method.
The method of claim 1, wherein the forming of the hierarchical multi-beams comprises:
Forming the hierarchical multi-beams having different coverage sizes according to the calculated total traffic amount;
Comparing the available capacity of the multi-beams per layer determined according to the coverage size of the hierarchical multi-beams with the calculated total traffic amount; And
Determining a hierarchical multi-beam providing a service to the terminals according to the comparison result.
3. The method of claim 2,
The comparing may include comparing each of the hierarchical multi-beams sequentially from the highest hierarchical multi-beams in the hierarchical multi-beams.
The method of claim 2, wherein the forming of the hierarchical multi-beams comprises:
If the calculated total amount of traffic does not exceed the available capacity of the multi-beams of the predetermined layer in the hierarchical multi-beams, determine service provision to the terminals through the multi-beams of the predetermined layer;
When the calculated total traffic amount exceeds the available capacity of the multi-beam of the predetermined layer, the available capacity of the multi-beam of the next lower layer of the multi-beam of the predetermined layer and the calculated total traffic amount in the hierarchical multi-beam Service providing method characterized in that to compare. The method of claim 1,
The allocating of resources and power to the hierarchical multi-beams may include assigning frequencies having different center frequencies to adjacent beams in the service area among the hierarchical multi-beams.
The method of claim 1, wherein allocating resources and power to the hierarchical multi-beams comprises:
Dividing a subcarrier of a frequency usable in the service area into a plurality of subcarrier groups; And
Allocating all subcarriers of the usable frequency to a center region of the hierarchical multi-beams, and assigning different subcarrier groups to edge regions of adjacent beams in the service region of the hierarchical multi-beams; Service providing method, characterized in that.
The method of claim 1, wherein allocating resources and power to the hierarchical multi-beams comprises:
Dividing a time period of a frame providing a service to the terminals into a first time period and a second time period, and dividing a subcarrier of the second time period into a plurality of subcarrier groups; And
Allocating all subcarriers of the first time period to a central region of the hierarchical multi-beams, and assigning different subcarrier groups to edge regions of adjacent beams in the service area among the hierarchical multi-beams; Service providing method, characterized in that.
The method of claim 1,
And transmitting the allocated resource and power allocation information to the terminals through a control channel corresponding to the hierarchical multi-beams, respectively.
The method of claim 1,
Receiving a service request signal from the terminals, the service providing method characterized in that for receiving the service request signal including the traffic information of each terminal through the uplink multi-beams of the lowest layer of the hierarchical multi-beams .
The method of claim 1,
The calculating of the total traffic amount may include checking the number of terminals to be provided with the service and the traffic amount of each terminal in the service area, and requesting the service area from the checked number of terminals and the traffic amount of each terminal. A service providing method comprising calculating the total traffic amount.
11. The method according to any one of claims 1 to 10,
The hierarchical multi-beam includes a global beam of the highest layer having the largest coverage size, a regional beam having a smaller coverage size than the global beam, and a lowest layer having the smallest coverage size. A service providing method comprising a spot beam.
A service providing system in a satellite communication system,
A plurality of terminals existing within a service area and receiving services by accessing the satellite communication system using one of a first communication method and a terrestrial auxiliary device or a second communication method through a network; And
When the service request signal is received from the terminals to be provided with the service in the service area, the total amount of traffic in the service area is calculated using the service request signal and covers the calculated total traffic amount. And a satellite base station that provides a service to the service area through a hierarchical multi beam.
Comparing the calculated total trapping amount with the available capacity of the hierarchical multi-beams in the service area, a multi-layer of a predetermined layer is formed in which the coverage size of the hierarchical multi-beams covers the calculated total trapping amount. Characterized by a service providing system.
The method of claim 12,
The satellite base station forms the hierarchical multi-beams having different coverage sizes according to the calculated total traffic amount, allocates resources and power to the hierarchical multi-beams, and allocates the allocated resources. And transmitting power allocation information to the service area through a control channel corresponding to the hierarchical multi-beam, respectively, and then providing a service through the hierarchical multi-beam with the allocated resource and power. Provide system.
The method of claim 13,
And the satellite base station assigns frequencies having different center frequencies to adjacent beams in the service area among the hierarchical multi-beams. The method of claim 13,
The satellite base station divides a subcarrier of a frequency usable in the service area into a plurality of subcarrier groups, allocates all subcarriers of the usable frequency to the center region of the hierarchical multi-beam, and assigns the hierarchical And a different subcarrier group is allocated to edge areas of adjacent beams in the service area among the multi-beams.
The method of claim 13,
The satellite base station divides a time period of a frame providing a service to the service area into a first time period and a second time period, and divides a subcarrier of the second time period into a plurality of subcarrier groups. All subcarriers of the first time period are allocated to the center region of the hierarchical multi-beams, and different subcarrier groups are allocated to edge regions of adjacent beams in the service region of the hierarchical multi-beams. system.
The method of claim 12,
The satellite base station provides a service through the multi-beam of the predetermined layer when the calculated total traffic amount does not exceed the available capacity of the multi-beam of the predetermined layer in the hierarchical multi-beam; When the calculated total traffic amount exceeds the available capacity of the multi-beam of the predetermined layer, the available capacity of the multi-beam of the next lower layer of the multi-beam of the predetermined layer and the calculated total traffic amount in the hierarchical multi-beam Service providing system, characterized in that for comparing.
18. The method of claim 17,
The satellite base station provides a service through the multi-beams of the predetermined layer when the calculated total traffic amount does not exceed the available capacity of the multi-beams of a predetermined layer in the hierarchical multi-beams, and calculates the total traffic amount. And when the available capacity of the multi-beams of the predetermined layer is exceeded, the available capacity of the multi-beams of the next lower layer of the multi-beams of the predetermined layer and the calculated total traffic amount are compared.
The method of claim 12,
The terminals are connected to the multi-beams of the lowest layer of the hierarchical multi-beams through the uplink, each of the service providing system, characterized in that for transmitting the service request signal including their own traffic information.
The method of claim 12,
The satellite base station checks the number of terminals and the amount of traffic of each terminal to receive a service in the service area, and calculates the total amount of traffic required in the service area from the number of the identified terminals and the amount of traffic of each terminal. A service providing system, characterized in that the calculation.
21. The method according to any one of claims 12 to 20,
The hierarchical multi-beam includes a global beam of the highest layer having the largest coverage size, a regional beam having a smaller coverage size than the global beam, and a lowest layer having the smallest coverage size. A service providing system comprising a spot beam.

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