KR102015600B1

KR102015600B1 - Wireless communication system using mobile base station and method for providing wireless communication service

Info

Publication number: KR102015600B1
Application number: KR1020130078292A
Authority: KR
Inventors: 최용훈; 김승배; 임한영; 이주용; 조동호
Original assignee: 한국과학기술원
Priority date: 2013-07-04
Filing date: 2013-07-04
Publication date: 2019-08-28
Also published as: KR20150005055A

Abstract

Disclosed are a wireless communication system and a method for providing a wireless communication service using a mobile base station. The present invention provides at least one mobile communication terminal provided with a wireless communication service, at least one fixed base station connected to a wired backbone network, and having a plurality of antennas to perform wireless communication using an ultrahigh frequency of 10 GHz band, and each It includes a plurality of antennas, performs wireless communication using at least one mobile communication terminal and at least one fixed base station using an ultra-high frequency, and includes a plurality of mobile base stations, wherein the plurality of mobile base stations each have a frequency band of 5 GHz or less It is characterized in that for performing the massive MIMO communication.

Description

WIRELESS COMMUNICATION SYSTEM USING MOBILE BASE STATION AND METHOD FOR PROVIDING WIRELESS COMMUNICATION SERVICE}

The present invention relates to a wireless communication system and a method for providing a wireless communication service, and more particularly, to a wireless communication system and method using a mobile base station.

BACKGROUND With the proliferation of portable mobile terminals such as smart phones and smart pads, the demand for wireless mass data transmission is rapidly increasing. The next generation mobile communication network infrastructure aims to secure 1000 times the capacity of the current communication capacity of about 100 Mbps. This is the capacity considering the traffic demand after 10 years in consideration of the increase of traffic twice a year. In order to increase the current data transmission capacity to the current 1000 times, the development of contents, platform, network, and terminal is required. Bottlenecks are very likely in the world. In current wireless communication systems, a large number of small cells are needed to increase data transmission capacity of a network. However, small cells such as macro cell base stations, WLANs, and femtocells all have to be connected by wired optical cables, which causes problems in terms of installation location and cost.

Nevertheless, high-capacity wireless backhaul, such as LMDS / LMCS (Local Multipoint Distribution Services / Local Multipoint Communication Services), is designed only for fixed base stations. There is a limit that cannot be solved.

Although WiBro (Wireless Broadband Internet) terminals are currently used as wireless backhaul to support wireless LAN in a vehicle, capacity limitations due to the frequency band used have not been overcome.

An object of the present invention is to provide a wireless communication system using a mobile base station to be able to utilize a variety of existing frequency bands, and to be able to cooperatively transmit data to a plurality of mobile base stations that are not limited to the installation site or installation cost.

Another object of the present invention is to provide a method for providing a wireless communication service using a mobile base station.

A wireless communication system according to an embodiment of the present invention for achieving the above object comprises at least one mobile communication terminal receiving a wireless communication service; At least one fixed base station connected to a wired or wireless backbone network and having a plurality of antennas to perform wireless communication using an ultra high frequency of a cellular or millimeter wave / terahertz band; And a plurality of mobile base stations, each of which comprises a plurality of antennas, performs wireless communication using the ultra high frequency with the at least one mobile communication terminal and the at least one fixed base station, and is movable. The base stations perform massive MIMO communications using cellular or millimeter wave / terahertz bands with each other.

The at least one fixed base station performs wireless communication using the ultrahigh frequency using a beamforming technique for a mobile base station within a LoS distance among the plurality of mobile base stations.

The plurality of mobile base stations may be installed in a vehicle or a portable terminal.

The present invention is not limited to the above-described embodiment, and as can be seen in the appended claims, modifications can be made by those skilled in the art to which the present invention pertains, and such modifications are within the scope of the present invention. Reveal.

Accordingly, a wireless communication system and a method for providing a wireless communication service using a mobile base station of the present invention include a plurality of mobile base stations, and a plurality of mobile base stations perform cooperative communication, so that an installation place for installing a small cell base station and Not limited by installation costs Therefore, a mobile base station can be easily installed in a vehicle, thereby providing a communication capacity linearly proportional to the number of base stations without a communication shadow area. In addition, it supports multi-band and multi-mode using existing communication bands below 5GHz and tens to hundreds of GHz bands, so that existing mobile communication networks can be utilized together. Therefore, a large data communication infrastructure can be provided to a plurality of mobile communication terminals.

1 illustrates a concept of a wireless communication system using a mobile base station according to the present invention.
2 shows a change in communication capacity according to the number of base stations for each communication scheme.
3 shows a change in communication capacity through cooperative communication of a mobile base station.
4 shows an example of the operation of the wireless communication system of the present invention.
5 illustrates a method for providing a wireless communication service using a mobile base station according to an embodiment of the present invention.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In addition, in order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals in the drawings indicate the same members.

Throughout the specification, when a part is said to "include" a certain component, it means that it may further include other components, without excluding the other components unless otherwise stated. In addition, the terms "... unit", "... unit", "module", "block", etc. described in the specification mean a unit for processing at least one function or operation, which means hardware, software, or hardware. And software.

1 illustrates a concept of a wireless communication system using a mobile base station according to the present invention.

As shown in FIG. 1, the wireless communication system according to the present invention includes, for example, a backbone contents switch (ACS), an access contents switch (ACS), an access antenna (AA), a dynamic link access network (DLAN), and a transport ad-hoc (TANET). Network) and a wired or wireless link.

In the present invention, the DLAN is a network providing a wired or wireless link to a user through an access antenna (AA) connected to the ACS. A plurality of access antennas (AA) may be connected to a wired or wireless link to expand a transmission link.

A plurality of access antennas (AA) are connected to a plurality of TBS (Transportation Base Station) and user terminals through a DLAN to provide communication capacity, and access through a wired or wireless connection in a network configuration of a mixed star and tree topology A backhaul network is formed to dynamically distribute communication resources to a plurality of TBSs and user terminals. The plurality of access antennas AA are mostly implemented in the form of a fixed base station, but are not limited thereto. In some cases, the access antennas AA may be implemented in the form of a mobile base station.

In addition, TANET is a transportation ad-hoc network, and may be configured as a mobile base station installed in a transportation means such as a car or a train and moving in accordance with the movement of an object. A mobile base station of a TANET receives a wireless link from a corresponding access antenna AA among a plurality of access antennas AA to provide a wireless communication service to a user's portable terminal. To this end, TANET's mobile base station is implemented to enable direct communication with the AN.

Here, TANET does not necessarily mean only a base station installed in a moving vehicle, but refers collectively to a base station installed in a transportation means, as shown in FIG. 1, as well as a mobile base station installed in a moving vehicle as well as a mobile type installed in a stationary vehicle. The base station is also included in the TANET.

In the present invention, the mobile base station installed in the mobile means of transportation as described above is called a TBS (Transportation Base Station). TBS can support dynamic coverage for mobile users, and users can be provided with large capacity services while using transportation through TBS.

The DLAN forms a connection network between the access antenna AA and the TBS and the user terminal, and provides a large communication resource with the TBS of the TANET, while providing a relatively low capacity communication resource with the user terminal.

As described above, in the wireless communication system of the present invention, the TBS is provided in a means of transportation and receives a wireless backhaul from an ACS connected to a BCS to provide a wireless communication service. Due to the nature of the wireless backhaul, the base station itself can be freely moved, unlike the existing fixed base station, the TBS of the present invention can be installed freely without being restricted by the installation location, and the installed location itself may be moved.

As shown in FIG. 1, the mobile base station may be installed in a vehicle such as a car or a train. In addition, even if installed in a fixed place, such as indoors, the user can freely move the location of the base station as needed. That is, the mobile base station may be variously installed in various things.

In addition, the user may carry the TBS directly. This means that the base station itself can be combined with the user's portable terminal, and the user's portable terminal can also function as a base station.

In addition, in the wireless communication system of the present invention, a plurality of TBSs may perform cooperative communication. As the plurality of TBSs may perform cooperative communication, the data transmission capacity of the wireless communication system may increase linearly in proportion to the number of base stations.

As described above, since the TBS is mounted on a vehicle or the like, the user can carry and move the mobile communication and cooperative communication is possible. In other words, the more users, the greater the number of base stations. In addition, since the data transmission capacity increases linearly in proportion to the number of TBSs, the wireless communication system of the present invention can actively cope with the increase in network traffic by increasing the transmission capacity in a densely populated area.

In addition, the wireless communication system of the present invention may be operated in parallel with a fixed base station using a conventional wired or wireless backhaul, instead of using only a mobile base station such as TBS.

In the present invention, the TBS is configured to support frequencies of various frequency bands, and a second frequency band (for example, in addition to a next generation mobile communication network using a first frequency band (for example, a frequency band of 5 GHz or more and 10 THz or less)). The existing mobile communication network using a frequency band of 1GHz or more and less than 5GHz can be used together. In addition, it is configured to utilize a WLAN network such as WiBro.

That is, the wireless communication system according to the present invention not only uses a frequency band of 5 GHz or more, but also uses all kinds of frequency bands of 5 GHz or less, which are used by existing mobile communication networks, unlike a conventional wireless communication system using a designated frequency band. .

2 shows a change in communication capacity according to the number of base stations for each communication scheme.

In FIG. 2, (a) illustrates a change in communication capacity according to the number of base stations in a wireless communication system using a resource division scheme such as a time division multiple access (TDMA) / frequency division scheme (FDMA). (B) shows a change in communication capacity according to the number of base stations in a wireless communication system using a multi-hop method, and (c) shows a change in communication capacity according to the number of base stations in a wireless communication system using a cooperative communication method. Indicates a change in communication capacity.

As shown in Fig. 2, the resource division scheme of (a) simply divides and utilizes limited communication capacity, so that the change in communication capacity does not occur even if the number of base stations that are communication nodes nd is increased. On the other hand, in the multi-hop wireless communication system of (b), since the base stations, which are communication nodes nd, relay transmission data, the communication capacity increases to (nd) ^1/2 according to the number of base stations. That is, as the number of base stations increases, the communication capacity initially increases rapidly, but when the number exceeds the predetermined number, the increase of the communication capacity decreases and the increase rate of the communication capacity decreases significantly compared to the increase rate of the number of base stations. However, in the wireless communication system applying the cooperative communication method of (c), the communication capacity increases linearly in proportion to the number of base stations as a plurality of base stations communicate with each other and transmit data separately. do. However, (c) assumes that the communication capacities of the plurality of base stations are the same. In practice, the communication capacities may be calculated in the form of an agreement of the communication capacities of the plurality of base stations. In the case of performing communication, interference may occur to cause a decrease in communication capacity.

Since the wireless communication system of the present invention uses a cooperative communication method, as the number of users increases, the number of base stations such as TBS increases, thereby increasing communication capacity to overcome communication obstacles. In particular, in the present invention, as the base station is implemented as a mobile base station using a wireless backhaul, it is very easy to increase the number of base stations.

3 shows a change in communication capacity through cooperative communication of a mobile base station.

Unlike the base station, the number of antennas of the mobile communication terminal to be provided with the wireless communication service is limited to the number of antennas that can be provided with emphasis on portability. In general, a mobile communication terminal is usually provided with only one antenna.

In this case, even if the number of antennas of a base station providing a wireless communication service to the mobile communication terminal is large, the communication capacity by MISO (Multiple Input Single Output) using a plurality of base station antennas and one mobile communication antenna is shown in FIG. Likewise, it does not increase significantly in comparison with the communication capacity by SISO (Single Input Single Output). In other words, even if the number of antennas of the base station is increased, the effect of increasing the communication capacity is not significant. In FIG. 3, the MISO shows a case in which 10 antennas are provided in a base station, whereas only one antenna is provided in a mobile communication terminal.

On the contrary, when the base station includes 10 antennas and the mobile communication terminal includes 10 antennas to apply MIMO (Multiple Input Multiple Output), as shown in FIG. 3, compared to MISO in the region of 25bps / Hz. A communication capacity gain of approximately four times or more can be achieved.

However, in the wireless communication system of the present invention, a plurality of mobile base stations perform cooperative communication with a mobile communication terminal, thereby maximizing the gain of communication capacity through MIMO. Detailed description thereof will be described later.

4 is an example of operation of the wireless communication system of the present invention, and shows an example of a TANET.

FIG. 4 illustrates a method for providing a communication service to a mobile communication terminal of a user who is moving by using a vehicle such as a vehicle. In FIG. 4, (a) shows that a conventional wireless communication system uses a vehicle such as a vehicle. And a method of providing a communication service to a mobile communication terminal of a user who is moving by using a mobile terminal, and (b) illustrates a method of providing a service to a mobile communication terminal by a TANET according to the present invention. As shown in (a), in the conventional wireless communication system, the number of mobile communication terminals that receive the wireless communication service has the communication capacity allocated to the access antenna AA by the access antenna AA connected to the wired or wireless backbone network. It distributes according to the wireless communication service directly. In addition, in the conventional wireless communication system, the bandwidth is not large as the communication is performed using a band of 5 GHz or less. Accordingly, when calculating the communication capacity for each mobile communication terminal of the wireless communication system of (a), communication capacity = (average frequency efficiency) * (bandwidth) / (number of mobile communication terminals) = 5bps / Hz * 20MHz / N = 100 Calculated at Mbps / N.

In contrast, in the TANET of the wireless communication system according to the present invention (b), a plurality of TBSs are installed in a transportation means. In addition, the access antenna AA connected to the wired or wireless backbone network communicates with the mobile communication terminal through a plurality of TBSs without directly communicating with the mobile communication terminal. Accordingly, the wireless communication system of the present invention is implemented by a combination of three types of communication between the access antenna AA and the TBS or the mobile communication terminal, cooperative communication between the TBS or the mobile communication terminal, and communication between the TBS and the mobile communication terminal. do.

First, the communication between the access antenna AA and the mobile base station or the mobile communication terminal performs communication using ultra high frequencies (5 GHz to 10 THz) of the first frequency band. Accordingly, the communication capacity between the access antenna AA and the TBS or the mobile communication terminal utilizes a very high frequency first frequency band, so that the communication capacity is (average frequency efficiency) * (bandwidth) = 5bps / Hz * 200MHz = 1Gbps. Can be calculated. Here, it is assumed that the ultra high frequency band used for communication is 10 GHz and the bandwidth is 200 MHz.

In other words, the use of ultra-high frequency has expanded the communication band 10 times compared to the existing wireless communication system. It is assumed here that the access antenna AA and the TBS are within a distance of a line of loss (Los). That is, the access antenna AA performs communication using an ultrahigh frequency with a TBS or a mobile communication terminal within a LoS distance.

LoS is a term generally used in communication systems. It refers to a distance in which electromagnetic waves can be reached in a straight line, not a specific distance concept. LoS is a distance that the electromagnetic wave can reach in a straight line, LoS may vary depending on the frequency of the electromagnetic wave used or the surrounding environment.

The communication between the TBS and the mobile communication terminal also performs communication using the ultrahigh frequency of the first frequency band, similarly to the communication between the access antenna AA and the TBS, so that the communication capacity is (average frequency efficiency) * (bandwidth) = 5bps / Hz * 200MHz = 1Gbps can be calculated. Here, it is assumed that the ultra high frequency band used for communication is 10 GHz and the bandwidth is 200 MHz. It is also assumed that the distance between the TBS and the mobile communication terminal is also within the distance of Los (Line of Sight).

The plurality of TBSs perform cooperative communication as described above, and the communication between the plurality of TBSs is classified again according to whether the distance between the TBSs is LoS or Non-Line of Sight (NLoS).

If the distance between the TBS is LoS, the communication between the TBS utilizing the ultra-high frequency of the first frequency band like the communication between the access antenna (AA) and the TBS or the communication between the TBS and the mobile communication terminal (average frequency efficiency) ) * (Bandwidth) = 5bps / Hz * 200MHz = 1Gbps Communication is performed.

However, if the distance between the TBS is NLoS, it is not possible to use the ultra-high frequency in the communication between the TBS, so as in the conventional wireless communication system uses a distributed MIMO using the second frequency band.

Each of the plurality of TBSs has a plurality of antennas. Assuming that the number of antenna groups of a plurality of TBSs performing cooperative communication is 10, the communication between TBSs at an NLoS distance is (average frequency efficiency) * (bandwidth) * (number of cooperative antenna groups) = 5bps / Hz * 20MHz * 10 Communication can be performed with a communication capacity of 1 = 1Gbps. Here, it is assumed that the frequency band of the second frequency utilized for communication is 5 GHz and the bandwidth is 20 MHz.

That is, since communication between the access antenna AA and the TBS, the cooperative communication between the TBS, and the communication between the TBS and the mobile communication terminal can communicate with a communication capacity of 1 Gbps, a communication capacity of 100 Mbps can be obtained. Compared to the existing wireless communication systems that are distributed according to the number, the communication capacity can be greatly increased, and the bottleneck effect can be reduced. That is, a plurality of mobile communication terminals can perform communication with a communication capacity of 1 Gbps without restriction of communication capacity. In particular, when the existing wireless communication system is crowded with a large number of users, the communication quality is greatly reduced by distributing the communication capacity, whereas the wireless communication system of the present invention is configured by incorporating a TBS with a mobile communication terminal or shown in FIG. As implemented in transportation as the number of users increases, the number of TBS increases and the number of cooperative antenna groups increases, so that the NLoS that utilizes the second frequency band as well as the LoS environment in which the TBS utilizes the ultra high frequency of the first frequency band. It can maximize the communication capacity even in the environment.

In this case, the TBS performing cooperative communication may be automatically configured to form an ad-hoc or network mesh network so as to secure capacity for traffic flowing into the plurality of TBSs.

5 illustrates a method for providing a wireless communication service using a mobile base station according to an embodiment of the present invention.

Referring to FIG. 5, a method of providing a wireless communication service using a mobile base station according to the present invention, first, an access antenna AA connected to a wired backbone network has a TBS (TBS) of a LoS distance among a plurality of TBSs (TBS1 to TBS4). TBS1) is determined (S10). Accordingly, the access antenna AA beamforms the TBS (TBS1) at a LoS distance to perform communication using an ultrahigh frequency of the first frequency band (S20).

In addition, the TBS (TBS1) communicating with the access antenna (AA) using the first frequency band has a LoLo distance from another TBS (TBS2 to TBS4) to provide a communication service to the mobile communication terminal (MS). It is determined whether or not (S30).

As a result of the determination, if there is a TBS (TBS2) within the LoS distance, communication with the TBS (TBS2) within the LoS distance using the ultrahigh frequency of the first frequency band is performed (S40). If there are mobile base stations (TBS3, TBS4) in the NLoS distance, the giant MIMO communication using the second frequency band is performed for the TBS (TBS3, TBS4) in the NLoS distance. At this time, the mobile base station (MBS1) can perform a huge MIMO communication with the TBS (TBS2) in the LoS distance with the TBS (TBS1), TBS (TBS3) also performs a huge MIMO communication with the TBS (TBS1, TBS2) can do.

The TBS (TBS4) located at a LoS distance from the mobile communication terminal (MS) performs ultra-high frequency communication of the first frequency band with the mobile communication terminal (MS) by using a beamforming technique.

Here, since the TBS (TBS4) performs ultra-high frequency communication with the mobile communication terminal (MS) by using a beamforming technique, the mobile communication terminal (MS) can be provided with a communication capacity of 1 Gbps even without a plurality of antennas. . That is, a large communication capacity may be serviced regardless of the number of antennas, which is a limitation of the mobile communication terminal (MS).

The method according to the invention can be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and also include a carrier wave (for example, transmission through the Internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims

At least one mobile communication terminal receiving a wireless communication service;
At least one fixed base station connected to at least one of a wired and wireless backbone network and having a plurality of antennas to perform wireless communication using an ultrahigh frequency of a first frequency band or a second frequency band; And
And a plurality of antennas, each of which may use the ultra high frequencies of the first frequency band and the second frequency band, and perform wireless communication using the ultra high frequency with the at least one mobile communication terminal and the at least one fixed base station. Perform, and include a plurality of mobile base stations,
The plurality of mobile base stations perform cooperative communication with a mobile communication terminal, and the communication capacity of the mobile communication terminal is increased in proportion to the number of mobile base stations in cooperative communication.

According to claim 1,
The at least one fixed base station,
And performing wireless communication using the ultra-high frequency using a beamforming technique for a mobile base station within a LoS distance among the plurality of mobile base stations.

According to claim 1,
The plurality of mobile base stations,
Wireless communication system, characterized in that installed in the means of transportation or portable mobile terminal.