KR20140077454A - High speed communication system using minimum interference repeating scheme - Google Patents

Abstract

The present invention relates to a high-speed communication system repeating data between nodes by using a moving station in minimum interference environments. The high-speed communication system according to one embodiment of the present invention comprises: an intra-network including an information source node transmitting data and an information target node receiving the data; and a moving station moving to search for a channel appropriate to a preset data transfer speed and signal quality and forming information transmission link to repeat the data from the information source node to the information target node. The high-speed communication system can transmit the data between the information source node and the moving station and between the information target node and the moving station by using a narrow beamwidth in a channel with a narrow bandwidth, and, if the moving station is two or more, transmit the data between the moving stations by using a wide beamwidth in a wide channel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high speed communication system using a minimum interference relay method,

The technical field relates to a high-speed communication system for relaying data between a node and a node using a moving object in a minimum interference environment.

As the demand for frequency resources increases with the development of wireless communication technology and the universalization of wireless communication services, studies for using frequency resources efficiently have been continuously studied.

Recently, cognitive radio technology, which is attracting attention as a frequency sharing technology, can be applied regardless of the frequency band, but TV white space is considered as the most suitable band at present. TV white space means an empty band that is not used locally in the TV broadcast band. That is, the frequency band that is freed when the primary user, such as a broadcasting service provider, is out of the frequency band permitted for providing the service is referred to as a white space.

Since the white space below 1GHz is excellent in radio wave characteristics and has a wider service coverage than 1GHz or higher frequency, it can be used to provide various services such as public safety, local information service, and super WiFi. For this reason, standards are being prepared for the use of white space in order to efficiently use frequency resources that are lacking in developed countries such as the United States, the United Kingdom, and the EU, and to provide various high quality services.

And technologies such as relay communication and beamforming are being studied as an extension technology of wireless transmission coverage. Relay communication is a communication method in which nodes that act as repeaters transmit information received from a source to other repeaters or destinations of information in order to widen the communication distance between the source of information and the destination of information. The relay node restores the received signal, corrects the error, and transmits the signal to another node, or amplifies and transmits the signal.

In the beamforming technique, a transmission signal is multiplied by a specific matrix so that the channel gain of a specific node is larger than that of a signal propagating in all directions, and the phase of the RF chain array is adjusted Thereby forming a beam in a specific direction. There is also a method of forming a beam using a very narrow beam width, such as a free-space optical communication laser.

In an object communication network that enables communication between a large number of mobile communication devices, a number of simultaneous connections that are difficult to cope with limited radio resources will be required, and this necessity results in a scalability problem or a performance problem of the wireless network will be.

The present invention can maintain the throughput performance of the intra-network and form a high-speed link between the information source of the intra-network and the information destination. The present invention uses a mobile body as a repeater, sets different communication links between a mobile body and an information source / information destination, and a communication link formed between a mobile body and a mobile body, It is possible to provide a system in which communication quality is optimized by the diversity effect of a plurality of moving objects.

The high-speed communication system using the minimum interference relaying method according to an embodiment of the present invention includes an intra-network including an information source node for transmitting data and an information target node for receiving data, And one or more mobile bodies that form an information transmission link for relaying data from the information source node to the information target node, wherein the information source node and the information target node The data can be transmitted / received using a narrow beam width in a channel having a narrow bandwidth between the moving objects, and the data can be transmitted / received using a wide beam width in a wide channel between moving objects when there are two or more moving objects.

The one or more moving objects can move to a position where no interference signal is detected from the intra network and a signal transmitted from the one or more moving objects does not interfere with the information source node and the information target node.

The present invention can maintain the throughput performance of the intra-network and form a high-speed link between the information source of the intra-network and the information destination.

The present invention also relates to a method and an apparatus for detecting interference of a communication link formed on a peripheral communication device by using a mobile object as a relay, setting a communication link formed between the mobile object and an information source / The influence can be minimized.

Further, the present invention can acquire a diversity effect by using a plurality of moving objects, and can optimize the communication quality.

1 is a block diagram of a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.
2 is a diagram illustrating a link budget of a downlink formed between a base station and a mobile station in a high-speed communication system using a minimum interference relaying scheme according to an embodiment of the present invention.
3 is a diagram illustrating a link budget of an uplink formed between a base station and a moving object in a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.
4 is a diagram illustrating the TV whitespace in Korea that can be used in a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.
5 is a diagram illustrating an example of performing hybrid beamforming in a high-speed communication system using a minimum interference relaying scheme according to an embodiment of the present invention.
6 to 10 are views illustrating a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.

Referring to FIG. 1, a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention may include an intra network 110 and mobile objects 120 and 121.

The minimum interference relaying method used in the present invention is a minimum interference relaying method used in the present invention in which the moving objects 120 and 121 move to a region where the influence of interference from the intra network 110 is minimal, Means a method of receiving data from the node 111, relaying the data, and transmitting the data to the information target node 113. As another example, the mobile units 120 and 121 may move to areas where the influence of interference on the intra network 110 is minimal.

In the example of FIG. 1, the information source node 111 and the information target node 113 belong to the same intra network 110, but in another example, the information source node 111 belongs to the intra network 110, The network 113 may belong to another intra network (not shown).

The intranet 110 may be used to refer to a dense network of communication devices. The communication device may be classified into a node transmitting information or a node receiving information.

The information source node 111 can transmit data to the information target node 113 using the mobile object 120 and the mobile object 121 as relay nodes. At this time, the information source node 111 and the moving object 120 may form a communication link 131. The information source node 111 and the moving object 120 can transmit and receive data using a narrow beam width in a channel having a narrow bandwidth of the communication link 131. [ Here, the narrow channel means that the channel is narrower than the channel communicating between the mobile 120 and the mobile 121. Also, the narrow beam width means that the beam width is narrower than the beam width used for communicating between the mobile 120 and the mobile 121.

In addition, the information source node 111 and the moving object 120 can transmit and receive data using a high modulation scheme in a channel having a narrow bandwidth of the communication link 131. Here, the high modulation scheme means a case where the modulation scheme is more complex than the modulation scheme used for communication between the mobile unit 120 and the mobile unit 121. [ For example, among the modulation schemes of 64QAM (Quadrature Amplitude Modulation), 16QAM, Quadrature Phase Shift Keying (QPSK), and BPSK (Binary Phase Shift Keying), the complexity is large in order of 64QAM> 16QAM> QPSK> BPSK. Among the examples, the 64QAM scheme is the highest modulation scheme and the BPSK scheme is the lowest modulation scheme.

The mobile body 120 and the mobile body 121 may form a communication link 133. [ The moving body 120 and the moving body 121 can transmit and receive data using a wide beam width in a wide channel of the communication link 133. [ Here, the wide channel means that the channel is wider than the channel communicating between the information source node 111 and the mobile 120. Further, the wide beam width means that the beam width used for communicating between the information source node 111 and the moving object 120 is wider.

In addition, the mobile unit 120 and the mobile unit 121 can transmit and receive data using a low modulation scheme in a channel having a wide bandwidth of the communication link 133. Here, the low modulation scheme means a case where the complexity is modulated in a relatively smaller manner than the modulation scheme used for communication between the information source node 111 and the mobile unit 120. [

The moving object 120 can receive data from the information source node 111 and can transmit the data to the moving object 121. [ The moving object 121 may transmit the received data to the information target node 113 again.

The information target node 113 and the mobile 121 may form a communication link 135. The information target node 113 and the moving object 121 can transmit and receive data using a narrow beam width in a channel in which the bandwidth of the communication link 135 is narrow. Here, the narrow channel means that the channel is narrower than the channel communicating between the mobile 120 and the mobile 121. Also, the narrow beam width means that the beam width is narrower than the beam width used for communicating between the mobile 120 and the mobile 121.

In addition, the information target node 113 and the mobile unit 121 can transmit and receive data using a high modulation scheme in a channel having a narrow bandwidth of the communication link 135. Here, the high modulation scheme means a case where the modulation scheme is more complex than the modulation scheme used for communication between the mobile unit 120 and the mobile unit 121. [ For example, among 64QAM, 16QAM, QPSK, and BPSK modulation schemes, the order of 64QAM > 16QAM > QPSK > Among the above examples, the 64QAM scheme is the highest modulation scheme and the BPSK scheme is the lowest modulation scheme.

The bandwidth of the channel of the communication link 131 and the channel of the communication link 135 may be formed to be narrower than the bandwidth of the channel of the communication link 133. [ The beam width of the beamforming used in the communication link 131 and the communication link 135 may be formed narrower than the beam width of the beamforming used in the communication link 133. [ For example, if the 64QAM scheme is used in the communication link 131 and the communication link 135, the BPSK scheme can be used in the communication link 133. [

Generally, a communication system based on Cognitive Radio Technology allows a secondary user (a Secondary User or an Unlicensed User) to utilize a frequency resource (White Space) not used by a primary user or a licensed user , Improving frequency resource utilization efficiency and improving overall network throughput.

However, in an environment in which frequency resources are limited such as object communication, a primary user is frequently used frequency resources to utilize frequency resources without being affected by interference or interfering with other devices in a secondary user , It is not easy for communication opportunities to be secured due to non-periodic and frequent connection attempts of the secondary users.

The present invention allows a mobile body 120 and 121 equipped with a mobile communication system to move until it finds a channel environment suitable for a predetermined data transmission rate or a signal quality so as to relay a signal in a better channel environment Method. Each of the mobile units 120 and 121 may be a moving means such as a car, an airplane, or a ship that is moved by a person to a destination, but may be a UAV (Unmanned Aerial Vehicle) Self-Driving Car (SDB) or Self-Driving Boat (SDB).

The present invention relates to a method and apparatus for maintaining the throughput of a dense intra-network 110 and forming a high-speed link between an information source node 111 and an information target node 113 of the intra-network 110 . Generally, in order to increase the channel capacity of the network, the cell size must be small, and the transmission power of the node included in the cell should be low. When one node included in the network increases the transmission power to use a service requiring a very high throughput, or widening the transmission bandwidth, it interferes with other peripheral devices, thereby reducing the throughput of the network.

The present invention includes a method for improving throughput by selectively using high quality links among a plurality of links.

Although the specific configuration of the present invention will be described herein with reference to an unmanned aerial vehicle, the present invention is not limited to an unmanned aerial vehicle but can be applied to a general moving means or a moving object.

Table 1 shows physical layer (PHY) parameters used in a high-speed communication system using a minimum interference relay scheme according to an embodiment of the present invention. This PHY parameter can be used to support communication coverage of 30 km or more and to support high-speed mobile communications of several tens of Mbps. Although the physical layer parameters in Table 1 are based on OFDM technology, the present invention can also be applied to the case of using technology-based physical layer parameters other than OFDM.

Parameters Values Notes Frequency <1 GHz Support worldwide TV channel (6MHz) in the UHF broadcast bands or support ISM band. Antenna Antenna gain: 9dBi (BS) / 6dBi (UAV) Max. RF transmit power
= 27dBm (BS) / 24dBm (UAV) EIRP: 36dBm (BS) / 30dBm (UAV) 36 dBm = 4 Watts
30 dBm = 1 Watts Noise figure 3 dB (BS) / 6 dB (UAV) Air interface OFDMA / TDD Bandwidth 6 MHz Signal bandwidth: ~ 5.62MHz FFT size 2048 per 1 channel (6 MHz) Number of guard subcarriers: 368
Number of used subcarriers: 1680
Number of data subcarriers: 1440
Number of pilot subcarriers: 240 Subcarrier spacing 3.3 kHz Channel bonding Up to 4 channels (Mandatory)
Up to 20 channels (Optional) 3 bandwidth modes: 6, 12, 24 MHz
Max. bandwidth: 120MHz Modulation and coding scheme CP: 1/4, 1/8, 1/16, and 1/32
Modulation: BSPK (or S-QPSK), QPSK, 16QAM, 64QAM
Codec: Convolutional coding w / 1/2, 2/3, 3/4, 5/6 rates. Short CP such as 1/16 or 1/32 may be used under static condition.
For QAM modulation, PHY optimized to tolerate long channel response and frequency selective channel
For BPSK and QPSK modulation, MAC provides compensation for long round trip delay
S-QPSK can provide ~ 2.5dB diversity gain; Duplicated data subcarriers over Q and I phase. Required SNR BPSK 1/2 (or S-QPSK): 1 to 3 dB
QPSK 1/2 to 5/6: 4 to 9 dB
16QAM 1 / 2-5 / 6: 10-15 dB
64QAM 1 / 2-5 / 6: 16-21 dB AWGN condition
80dBc / Hz at 1kHz and 10kHz
105dBc / Hz at 100kHz Symbol time 298.7 us Max CP time 74.7 us Robustness to delay spread Peak data rate 22.7 Mbps 1/32 CP mode, 64QAM, 5/6 rate
45.4 and 90.8Mbps for 12MHz and 24MHz BW mode, respectively. Max. 분광율 3.12 bits / s / Hz

2 is a diagram illustrating a link budget of a downlink formed between a base station and a mobile station in a high-speed communication system using a minimum interference relaying scheme according to an embodiment of the present invention.

Referring to FIG. 2, an unmanned aerial vehicle (UAV) is used as an example of a moving object. The base station corresponds to the information source node 111 of FIG. 1, and the UAV corresponds to the mobile 120. In the case of FIG. 2, it is the link budget when the base station transmits data to the UAV. Link budget refers to specifications of the transmitter and receiver required to perform communication on the link. The link budget shown in FIG. 2 is an example for supporting a communication coverage of up to 30 km, and the output power of the transmitter and the noise specification of the receiver may vary depending on the system requirements.

In order to guarantee 30 km coverage with the PHY parameter shown in Table 1, it can be seen that the signal-to-noise margin margin is about 23.7 dB. Therefore, in a communication modem, the signal-to-noise ratio should be designed to be smaller than this margin.

3 is a diagram illustrating a link budget of an uplink formed between a base station and a moving object in a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.

Referring to FIG. 3, an unmanned aerial vehicle (UAV) is used as an example of a moving object. The base station corresponds to the information target node 113 of FIG. 1, and the UAV corresponds to the mobile 121. In the case of FIG. 3, it is the link budget when data is transmitted from the UAV to the base station. Link budget refers to specifications of the transmitter and receiver required to perform communication on the link. The link budget shown in FIG. 3 is an example for supporting a communication coverage of up to 30 km, and the output power of the transmitter and the noise specification of the receiver may be different according to the system requirements.

In order to guarantee 30 km coverage with the PHY parameter shown in Table 1, it can be seen that the signal-to-noise margin margin is about 23.7 dB. Therefore, in a communication modem, the signal-to-noise ratio should be designed to be smaller than this margin.

4 is a diagram illustrating the TV whitespace in Korea that can be used in a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.

Referring to FIG. 4, examples of TV white space 410, 420, 430, 440 and 450 are shown. In our country, TV space is relatively small and the frequency band of TV occupation is high, so TV whitespace is relatively small, but there are many white spaces in foreign countries (especially USA etc). 4 is two-dimensionally illustrated with respect to the ground frequency. However, in the three-dimensional view, each circle is drawn in a sphere shape, and as the distance from the ground is increased, the number of white spaces can be increased.

5 is a diagram illustrating an example of performing hybrid beamforming in a high-speed communication system using a minimum interference relaying scheme according to an embodiment of the present invention.

5, the beam width 510 formed by the base station and the UAV 3, and the beam width 530 formed by the UAV 2 and the MT (Mobile Terminal) UAV3) and the beam width 520 formed by the UAV2. That is, since the high-speed communication system using the minimum interference relay scheme uses the narrow beam widths 510 and 53 and the wide beam width 520 in a mixed manner, the hybrid beamforming can be performed.

The base station and the UAV3 use a high modulation scheme of 64QAM at a narrow bandwidth of 24MHz and the UAV3 and the UAV2 use S-QPSK at a wide bandwidth of 120MHz. Use a low modulation scheme. Unmanned aircraft (UAV2) and mobile terminal (MT) also use a high modulation scheme of 64QAM in a narrow bandwidth of 24MHz.

In order to prevent the intra-network throughput from decreasing due to the interference signal on the channel in the long-distance communication, the mobile unit does not detect the interference signal from the intra-network and the signal transmitted by the mobile unit interferes with the communication apparatus included in the intra- So that the throughput of the intra network can be maintained by high-speed wireless communication.

The information source node / information target node of the intra network transmits data using a high modulation method in a narrow channel between the mobile node and the moving object, and transmits data using a low modulation method in a wide channel between the moving object and the mobile object, A link can be formed.

The moving object can find a position that does not cause interference with another communication device in a two-dimensional plane, but it can also be searched at a high altitude in a three-dimensional space.

In order to use a high modulation scheme in a narrow channel, a beam-type communication scheme with a narrower beam width can be used. The narrower the beam, the less the effect of interference on other nearby wireless communication devices. However, the narrower the beam, the more difficult it is to beam pointing and tracking the moving object, and the more likely the link becomes unstable. Therefore, a high-speed transmission is performed using a narrow beam width and a high-order modulation scheme using a narrow bandwidth between a fixed base station and an unmanned air vehicle (UAV3), between a mobile terminal (MT) and an unmanned air vehicle (UAV2) Between aircraft (UAV3) and unmanned aerial vehicle (UAV2), the beam width is relatively wide in a wide bandwidth, and a high-speed transmission is possible using a low-order modulation method.

Beamforming is an information transmission method in which energy radiated from an antenna is radiated intensively along a specific direction. The purpose of beamforming is to receive a signal from a desired direction or to transmit a signal in a desired direction. By emitting a directional beam only to a specific node instead of an omnidirectional antenna forming an omni-directional beam, the influence of interference on other nodes operating outside the beam width is minimized, thereby improving communication quality and increasing channel capacity have.

In a high-speed communication system using a minimum interference relaying scheme according to an exemplary embodiment, a beam width is narrowly transmitted in a narrow bandwidth in an intranet network in which mobile communication nodes are dense, and a wide beam width is used in a wide band between relay nodes outside the intra- do.

The reason why such hybrid beam forming is effective is as follows. 1) It is advantageous to narrow the beam width because the channel capacity deterioration due to the interference becomes worse as the mobile communication node is concentrated, and since many mobile communication nodes will compete more to occupy the bandwidth, It is advantageous. 2) In areas where mobile communication nodes are not concentrated, there is room for beam width and bandwidth. However, beam pointing and beam tracking between the information source node / information target node and relay node on the ground are somewhat easy, but beam pointing and beam tracking between two relay nodes becomes much more difficult. This is because both relay nodes are moving dynamically. Therefore, it is advantageous to widen the beam width for stable link connection between two relay nodes, and communication must be performed at a distance far greater than the communication distance between the information source node / information target node and the relay node. Therefore, You must allocate bandwidth.

6 to 10 are views illustrating a high-speed communication system using a minimum interference relaying method according to an embodiment of the present invention.

Referring to FIG. 6, a plurality of communication links can be formed by using a plurality of UAVs. By using a communication link having excellent link quality among a plurality of communication links, the throughput of a high-speed communication system using the minimum interference relaying scheme according to an embodiment can be improved. A communication link can be formed between the base station and the UAV 3 a, and between the base station and the UAV 3 b. A communication link can be formed between the UAV 3a and the UAV 2a and between the UAV 3b and the UAV 2b. A communication link can be established between the mobile terminal MT and the UAV 2a, and between the mobile terminal MT and the UAV 2b. The link quality (interference level, signal-to-noise ratio, etc.) of the two communication links at the base station can be measured, and a communication link with excellent link quality can be determined. It is possible to measure the link quality of two communication links in the mobile terminal MT and to determine a communication link with excellent link quality.

Referring to FIG. 7, a base station can transmit data to a mobile terminal MT using a UAV 3a and a UAV 2a as a relay node. The base station can transmit data to the mobile terminal MT using the UAV 3b and the UAV 2c as relay nodes when the UAV 3 a and the UAV 2 a are difficult to use. The base station can transmit data to the mobile terminal MT using the UAV 3c and the UAV 2b as relay nodes when the UAV 3 a and the UAV 2 a are difficult to use.

Also, instead of the UAV3a, UAV3b and UAV3c may be replaced with relay nodes. Unmanned aircraft (UAV2a), UAV2b, and UAV2c may be replaced with relay nodes. The base station can perform cooperative communication.

Referring to FIG. 8, when an overload occurs in traffic of some sub-networks 820 in a centralized information collecting system, the mobile units 830 and 840 of the present invention can be used as means for distributing traffic. That is, the traffic is distributed to the adjacent information collecting system 810, and the performance of the system can be maintained without deteriorating the service quality that the user feels.

Referring to FIG. 9, in a wireless sensor network, the positions of the sensors are normally distributed irregularly, and the sensors are designed with a low power structure, and the infrastructure construction cost for collecting the sensor information is consumed. By using the moving object of the present invention, the moving object can move and transmit information collected from the wireless sensor network 910 at a high speed. Information collected from the wireless sensor network 910 by the UAV can be transmitted to a base station and the base station can transmit information to the UAV1 using the UAV2 as a relay node. The UAV 1 can transmit the received information to the wireless sensor network 920. In addition, the UAV 1 can collect information from the wireless sensor network 920 and use the UAV 2 as a relay node to forward information to the base station.

Referring to FIG. 10, the moving object of the present invention can operate as a noise generator for disabling a remote communication means at a remote location for military purposes. The unmanned air vehicle (UAV1) 1010 can transmit a jamming signal to an area where a communication device is located according to the control of a signal transmitted from the base station, using the UAV2 as a relay node.

The present invention enables high-speed communication with a node located at a remote location. The present invention relates to a method and apparatus for moving a mobile body to a position where a wider bandwidth can be used (a high altitude or an area in which interference is less affected) to perform high-speed remote transmission over a wide bandwidth, The node uses a directional antenna with a narrow bandwidth to perform high-speed transmission.

In the case of the long-distance wireless transmission, the height of the antenna and the interference to the peripheral device must be considered at the same time, and the data can be transmitted by moving to a distance capable of one-hop transmission or moving to a position where no interference occurs.

Further, the present invention can obtain a multi-node diversity effect using multiple nodes, which is possible by selectively using a link with good link quality by sharing link quality information between relay nodes, an information source node, and an information target node .

The methods according to embodiments of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (1)

An intra-network including an information source node for transmitting data and an information target node for receiving data; And
The mobile node moves to search for a channel suitable for a predetermined data transmission rate and signal quality and includes at least one moving object forming an information transmission link for relaying data from the information source node to the information target node,
And transmitting and receiving the data using a narrow beam width between the information source node and the mobile object, and between the information target node and the mobile object,
In the case where there are two or more moving objects, the mobile station transmits and receives the data using a wide beam width in a wide channel
High - speed communication system using minimum interference relaying method.

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