KR102034025B1 - Method and apparatus for frequency allocation - Google Patents

Abstract

The present invention relates to a method and apparatus for allocating a frequency band, the method comprising: a frequency band allocation method of a first base station and a second base station having the same frequency band and transmitting simultaneously to form a double cell coverage; Allocating a first resource block (RB) for a first purpose in a first band, which is a frequency band; Allocating a virtual second frequency resource that is different from a first frequency resource in the first band and to reserve the first purpose; And
And allocating a third frequency resource in a second band which is a frequency band of the second base station, wherein the third frequency resource is the same frequency band as the second frequency resource and is for the first purpose. Frequency band allocation method. According to the present invention, it is possible to efficiently construct frequency resources in a redundant structure of a railroad wireless communication network in which reliability and stability must be guaranteed.

Description

Frequency band allocation method and apparatus {Method and apparatus for frequency allocation}

The present invention relates to a method and apparatus for allocating a frequency band, and more particularly, the present invention provides a method for efficiently constructing frequency resources in a redundant structure of a railroad wireless communication network in which reliability and stability must be ensured. The present invention relates to a method and apparatus for allocating a frequency band which proposes a method that can be used in common with a target wireless communication network.

Replace the train control method that was composed of wires between ground facilities and newly establish the control division of the ground and on-board equipment from the functional side, and secure and simple wireless communication based railway control system (CBTC) using wireless. It has been developed and put into practical use in some countries, and according to the trend of technology development, it is expected that wireless communication based train control and communication system will be applied to railway more widely than now.

The CBTC system is installed on the ground and on the vehicle, and ensures the stability of train operation through continuous communication with each other. In addition, compared to the traditional wired-based signal control system, the driving time can be shortened, which can increase the transportation capacity, and the data communication between the train and the central control system enables the train to be operated more efficiently. Convenience can be optimized.

  In Europe, the CBTC system uses GSM-R by allocating a portion of the GSM band to railroads in Europe, and in some countries including the United States, the IEEE 802.11 standard of the 2.4 GHz Industrial Scientific Medical (ISM) band is used. Used for train control. The wireless communication of CBTC system, which is used in Korea, such as Shin Bundang Line, uses 2.4GHz ISM band, and plans to install CBTC system using ISM band in the future.

  However, the RF-CBTC system using the ISM band is difficult to ensure continuous performance due to the problems of interference and interference due to the characteristics of the 2.4GHz band, and it is pointed out that there is concern about the interruption of railway operation. As a countermeasure, it is necessary to secure a dedicated railway frequency. Considering the domestic situation in the 2.4 GHz band, uncertainties in operation may occur due to interference and interference, and difficulties in frequency distribution procedures and periods occur for stable train operation. It is very necessary to secure a dedicated frequency.

However, when the wireless data is exploding in recent years, it is not easy to allocate a lot of frequency ranges for railways only. In particular, redundancy of railway network and cell coverage must be established in case of emergency. In conclusion, in the existing LTE system, twice the frequency requirement is required to eliminate the frequency interference between adjacent base stations for constructing the railway communication network. In this case, there is a problem in that the frequency efficiency is drastically deteriorated because two times the frequency is additionally required to duplicate the train control signal having a small transmission amount. On the other hand, Korean Patent Publication No. 2007- 0068162 and the like merely discloses the redundancy to increase the transmission capacity capacity, a technique for improving the efficiency and stability of the limited frequency.

In addition, since the main use area of railway radio communication is limited to near railway stations or railway lines, the frequency utilization efficiency is very low because the frequency is not used elsewhere. In order to overcome this problem, there is a need for efficient frequency duplication and linkage with other communication networks without affecting the important functions of the railway communication network.

An object of the present invention is to provide efficient frequency allocation by preventing frequency interference in a duplex structure of a railway wireless communication network which should guarantee reliability and stability.

An object of the present invention is to be able to use a railroad wireless communication network that should ensure reliability and stability in common with other purpose wireless communication network.

An object of the present invention is to improve reception sensitivity through synchronization of each base station signal in a duplex structure of a railway wireless communication network which should guarantee reliability and stability.

A frequency band allocation method according to the present invention for achieving the above object has a frequency band allocation method of the first base station and the second base station having the same frequency band and forming a dual cell coverage, Allocating a first resource block (RB) for a first purpose in a first band, which is a frequency band; Allocating a virtual second frequency resource that is different from a first frequency resource in the first band and to reserve the first purpose; And allocating a third frequency resource in a second band which is a frequency band of the second base station, wherein the third frequency resource is the same frequency band as the second frequency resource and is for the first purpose. It features.

At this time, after the step of allocating the third frequency resource, and in the same band of the first band and the second band is a frequency band different from the first frequency resource, the second frequency resource and the third frequency resource The method may further include allocating fourth frequency resources for a second purpose different from the first purpose.

In this case, after the allocating the third frequency resource, the method may further include a synchronization step of sharing and controlling the time point of the transmission signal of the first base station and the second base station.

In this case, the second frequency resource may have the same capacity as the first frequency resource.

In this case, the first object may be an object for controlling the moving object by simultaneously transmitting a signal to the first base station and the second base station.

At this time, the frequency of the first base station and the second base station may be a railway frequency.

In addition, the frequency band allocation apparatus according to the present invention for achieving the above object has the same frequency band with each other, and in the frequency band allocation apparatus of the first base station and the second base station forming a double cell coverage, A first allocator for allocating a first frequency resource for a first purpose in a first band which is a frequency band of the first base station; A second allocator which is different from a first frequency resource in the first band and allocates a virtual second frequency resource to reserve the first purpose; And a third allocating unit for allocating a third frequency resource in a second band, which is a frequency band of the second base station, wherein the third frequency resource is the same frequency band as the second frequency resource. It is characterized by.

In this case, a frequency band different from the first frequency resource, the second frequency resource, and the third frequency resource in the same band of the first band and the second band, for a second purpose different from the first purpose The apparatus may further include a fourth allocator configured to allocate fourth frequency resources, respectively.

At this time, the first base station and the second base station may further include a synchronization unit for sharing and controlling the time point of the transmission signal.

In this case, the second frequency resource may have the same capacity as the first frequency resource.

In this case, the first object may be an object for controlling the moving object by simultaneously transmitting a signal to the first base station and the second base station.

At this time, the frequency of the first base station and the second base station may be a railway frequency.

The present invention has an effect of efficient frequency allocation by preventing frequency interference in the duplex structure of the railway wireless communication network which should guarantee reliability and stability.

The present invention has the effect of improving the frequency utilization efficiency by using the railway wireless communication network in common with other wireless communication network while ensuring reliability and stability.

The present invention has the effect of improving the reception sensitivity through synchronization of each base station signal in the duplex structure of the railway wireless communication network to ensure the reliability and stability.

FIG. 1 is a diagram illustrating the duplication of a base station and a switching center configured in the GSM-R.
2 is a block diagram of a frequency allocation apparatus according to the present invention.
3 is a flowchart illustrating a frequency allocation method according to the present invention.
4 is a diagram illustrating a cell coverage duplex structure.
5 is a diagram illustrating a state in which a first frequency resource and a second frequency resource are allocated.
6 is a diagram illustrating a state in which a third frequency resource is allocated.
7 is a diagram illustrating a state of allocating a fourth frequency resource.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Here, the repeated description, well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention, and detailed description of the configuration will be omitted.

Railway wireless communication must double cell coverage to ensure reliability and network availability. In particular, in a communication scheme such as orthogonal frequency division multiplexing (OFDM) adopted by Long Term Evolution (LTE), frequency resources must be additionally provided to duplicate cell coverage.

1 is a diagram illustrating a base station and switching center duplex configured in the Global System for Mobile Communications-Railway (GSM-R). Fault conditions in one Base Station Transceiver Subsystem (BTS) 21a, 22a, or one Control Station (BSC) Base Station Controller (BSC) 30a or one Switching Station (MSC) 40a. When it occurred, the network was configured so that it could be immediately changed into the base stations 21b and 22b, the control station 30b, and the switching station 40b, which were prepared in advance.

Here, the first coverage 11a is cell coverage formed in the 21a base station, and the first coverage 12a is cell coverage formed in the 22a base station. In addition, the second coverage 11b is cell coverage formed in the 21b base station, and the second coverage 12b is cell coverage formed in the 22b base station. In addition, the on-board wireless signal receiver separately receives the radio signals transmitted from the first coverages 11a and 12a and the second coverages 11b and 12b (both signals are the same train control signal) and uses only one of them. If the received signal is unexpectedly disconnected, the second radio signals 11b and 12b which are waiting to be used are seamlessly used in the middle. That is, the on-board wireless signal receiver uses a wireless signal of the first coverages 11a and 12a, and employs a hot standby method in which a wireless signal of the second coverages 11b and 12b is received but not used. do. On the other hand, in the case of GSM-R, a subchannel having a 200 kHz bandwidth among the all allocated frequency bands can be organically allocated to each cell coverage so as to allocate interference to each frequency to be minimized. In this case, the entire allocated frequency band is used in one cell coverage instead of the subchannel scheme. For example, in FIG. 1, since the entire specific frequency bandwidth is allocated to the first coverages 11a and 12a, the interference between the same frequencies may be removed only by assigning a new frequency to the overlapping second coverages 11b and 12b. Therefore, in case of LTE, additional frequency allocation to a spare base station is required to avoid co-frequency interference.

In conclusion, in the existing LTE system, twice the frequency requirement is required to eliminate the frequency interference between adjacent base stations for constructing the railway communication network. In this case, the frequency efficiency is drastically reduced because an additional frequency twice as much as the existing requirement is needed to duplicate a train control signal with a small transmission amount. The present invention proposes a method for duplication of cell coverage without additional frequency resource allocation in a communication scheme such as OFDM or WCDMA. In addition, it also suggests the use of railway communication and other communication networks.

Hereinafter, the configuration and operation of the frequency allocation device according to the present invention will be described. 2 is a block diagram of a frequency allocation apparatus according to the present invention. 4 is a diagram illustrating a cell coverage duplex structure.

Referring to FIG. 2, the frequency allocating apparatus 100 according to the present invention operates by a processor and includes an allocation unit 110 and a synchronization unit 120, and the allocation unit 110 is a first allocation unit. 111, the second allocating unit 112, the third allocating unit 113, and the fourth allocating unit 114 are included. Referring to FIG. 2 and FIG. 4, the operation of the frequency allocation apparatus 100 according to the present invention will be described. The first base station 1 and the first base station having the same frequency band and simultaneously transmitted to form a double cell coverage There are two base stations 2. The first coverage 10a formed by the first base station 1 and the second coverage 10b formed by the second base station 2 overlap each other, and trains are provided through the redundant cell coverage. The control of 50 is instructed. At this time, in the redundant dual coverage 10c, the signal of the first base station 1 and the signal of the second base station 2 need to be transmitted without interference. Therefore, the frequency bands of the first base station 1 and the second base station 2 should be efficiently allocated.

The first allocator 111 allocates the first frequency resource for the first purpose in the first band, which is the frequency band of the first base station 1. In this case, the first purpose refers to the purpose for controlling the train, and is not limited to the purpose for controlling the train, and it is preferable that the first purpose be a stability or reliability.

The second allocator 112 is a band different from the first frequency resource in the first band, and allocates a virtual second frequency resource to reserve the first purpose. The term "virtual" as used herein means substantially leaving the second frequency resource blank without assigning it for a specific purpose. In addition, the second frequency resource may have the same capacity as the first frequency resource.

The third allocating unit 113 allocates the third frequency resource in the second band which is the frequency band of the second base station 2. The third frequency resource is the same frequency band as the second frequency resource and is a frequency resource for the first purpose.

The fourth allocation unit 114 is a frequency band different from the first frequency resource, the second frequency resource and the third frequency resource in the same band of the first band and the second band, and is different from the first purpose. Allocates a fourth frequency resource for a second purpose. The second object here means a communication network other than the purpose for controlling the train. Accordingly, the fourth frequency resource does not overlap with the first frequency resource, the second frequency resource, and the third frequency resource for controlling the train, thereby ensuring reliability and stability for controlling the train, and thus, other wireless communication networks in the railway communication network. Will be available. Detailed processes performed by the first assigning unit 111, the second assigning unit 112, the third assigning unit 113, and the fourth assigning unit 114 will be described later with reference to FIGS. 5 to 7. do.

In addition, the synchronization unit 12 serves to share and control the time point of the transmission signal of the first base station 1 and the second base station 2. Train control communication redundancy is a concept of transmitting exactly the same train signal from different neighboring base stations. Therefore, in the OFDM scheme, if the same train control signal is transmitted simultaneously on the same frequency resource as shown in FIG. Can be increased to receive. To do this, the signals sent from both base stations must share the correct transmission time with each other, and synchronization is required to control the timing of the transmission of the train control signal from the base station. For example, when the train control signal A transmitted from the first base station 1 and the train control signal B which is the same signal as the train control signal A transmitted from the second base station 2 are sent in the same frequency range, The control signal receiver may receive the same train control signal without interference or with better reception sensitivity.

Hereinafter, a frequency allocation method will be described in the present invention. 3 is a flowchart illustrating a frequency allocation method according to the present invention. 4 is a diagram illustrating a cell coverage duplex structure.

Referring to FIG. 3, in the frequency band allocation method of the first base station 1 and the second base station 2 having the same frequency band and transmitting simultaneously to form a double cell coverage, the frequency allocation according to the present invention The method 100 may include allocating a first frequency resource (RB) resource block (RB) for a first purpose in a first band, which is a frequency band of the first base station (S10), wherein the first frequency resource is allocated to the first band. Allocating a virtual second frequency resource that is another band to reserve the first purpose (S20), and allocating a third frequency resource in a second band that is a frequency band of the second base station (S30). And wherein the third frequency resource is the same frequency band as the second frequency resource and is for the first purpose.

In addition, after the step of allocating the third frequency resource, a frequency band different from the first frequency resource, the second frequency resource and the third frequency resource in the same band of the first band and the second band, The method may further include allocating a fourth frequency resource for a second purpose different from the first purpose (S40).

In addition, after allocating the third frequency resource, the method may further include a synchronization step of sharing and controlling the time point of the transmission signal of the first base station and the second base station.

Referring to FIGS. 3 and 4, the operation of the frequency allocation method according to the present invention will be described with reference to a first base station 1 and a second base station 1 having the same frequency band and transmitting simultaneously to form dual cell coverage. 2) exists. The first coverage 10a formed by the first base station 1 and the second coverage 10b formed by the second base station 2 overlap with each other, and such a dual redundant coverage 10c exists. Through the control of the train 50 is instructed. At this time, in the dual coverage 10c, the signal of the first base station 1 and the signal of the second base station 2 need to be transmitted without interference. Therefore, the frequency bands of the first base station and the second base station having the same frequency band and transmitting simultaneously to form the dual coverage 10c should be efficiently allocated.

Allocating a first frequency resource (S10) allocates a first frequency resource for a first purpose in a first band, which is a frequency band of the first base station 1. In this case, the first purpose refers to the purpose for controlling the train, and is not limited to the purpose for controlling the train, and it is preferable that the first purpose be a stability or reliability.

Allocating a second frequency resource (S20) is a band different from the first frequency resource in the first band, and allocates a virtual second frequency resource to reserve the first purpose. The term "virtual" as used herein means substantially leaving the second frequency resource blank without assigning it for a specific purpose. In addition, the second frequency resource may have the same capacity as the first frequency resource.

Allocating a third frequency resource (S30) allocates a third frequency resource in a second band, which is a frequency band of the second base station 2. The third frequency resource is the same frequency band as the second frequency resource and is a frequency resource for the first purpose.

Allocating a fourth frequency resource (S40) is a frequency band different from the first frequency resource, the second frequency resource and the third frequency resource in the same band of the first band and the second band. Allocates a fourth frequency resource for a second purpose different from the first purpose. The second object here means a communication network other than the purpose for controlling the train. Accordingly, the fourth frequency resource does not overlap with the first frequency resource, the second frequency resource, and the third frequency resource for controlling the train, thereby ensuring reliability and stability for controlling the train, and thus, other wireless communication networks in the railway communication network. Will be available. Detailed procedures of allocating the first frequency resource, allocating the second frequency resource, allocating the third frequency resource, and allocating the fourth frequency resource are described with reference to FIGS. 5 to 7. It will be described later through.

In addition, the synchronization step (S50) serves to share and control the time point of the transmission signal of the first base station 1 and the second base station (2). Train control communication redundancy is a concept of transmitting exactly the same train signal from different neighboring base stations. Therefore, in the OFDM scheme, if the same train control signal is transmitted simultaneously on the same frequency resource as shown in FIG. Can be increased to receive. To this end, signals sent from both base stations must share the exact time of transmission with each other, and synchronization is required to control when the train control signals are sent from outside the base station. For example, when the train control signal A transmitted from the first base station and the train control signal B, which is the same signal as the train control signal A transmitted from the second base station, are sent in the same frequency range RB, the train control signal receiving unit Can receive the same train control signal without interference or with better reception sensitivity.

Hereinafter, a process of allocating a first frequency resource, a second frequency resource, and a third frequency resource in the frequency allocation apparatus and method will be described. 5 is a diagram illustrating a state in which a first frequency resource and a second frequency resource are allocated. 6 is a diagram illustrating a state in which a third frequency resource is allocated.

Referring to FIG. 5, the first frequency resource 210 for the first purpose is allocated in the first band 200a which is a frequency band of the first coverage formed by the first base station. It is preferable that the said 1st objective is an objective for controlling a train. However, the present invention is not limited to the purpose for controlling the train, and may be various purposes for pursuing reliability and stability. In addition, in the first band 200a, a band different from the first frequency resource 210 is allocated and a virtual second frequency resource 220 is allocated to reserve the first purpose. In this case, the second frequency resource 220 preferably has the same capacity as the first frequency resource. Allocating to reserve a first purpose actually means securing the second frequency resource in the first band. That is, to secure the band to which the third frequency resource is allocated in the second band to be described later. In relation to the process of allocating the third frequency resource, referring to FIG. 6, the third frequency resource is allocated in the second band 200b which is a frequency band of the second base station. The third frequency resource has the same frequency band as the second frequency resource and is for the first purpose. That is, the third frequency resource is allocated to the band of the second frequency resource by emptying the second frequency resource. Accordingly, by allocating a frequency band in consideration of interference in the structure of dual cell coverage, frequency allocation having an efficient dual cell coverage structure that prevents interference between frequencies can be performed.

Hereinafter, a process of allocating a fourth frequency resource in the frequency allocation apparatus and method will be described. 7 is a diagram illustrating a state in which a fourth frequency resource is allocated.

Referring to FIG. 7, a scheme in which a railway network and another wireless communication network share the same frequency band is proposed. In general, in order to establish a wireless communication network, cell coverage should be configured so that there are no trouble areas anywhere in the country by installing base stations nationwide. However, it is common for railway networks to form cell coverage in an elliptical shape based on railroads. Therefore, it is very inefficient in terms of frequency utilization efficiency when a specific frequency is allocated for railway communication network and used only on railroad tracks. Therefore, it is possible to build and use a wireless communication network for other purposes in areas other than the railway network. In this case, the most important problem is how to operate the communication network used for other purposes in the railway area. If different wireless access standards are used, they are not compatible with each other, but if they use radio access standards such as railway wireless communication networks, they are compatible. If it is assumed that they are compatible, there should be no influence of compatibility on the stability of the rail network stability which is important for reliability and stability. In other words, train control used in railway communication network or broadcasting and group call function in case of railway accident should not be affected by other wireless communication network. Thus, a second frequency band different from the first frequency resource, the second frequency resource, and the third frequency resource in the same band of the first band and the second band, and for a second purpose different from the first purpose. Four frequency resources 240 may be allocated respectively. In other words, train frequency resources 260 that can transmit vital vital information in railway wireless communication must be secured. The train frequency resource 260 corresponds to the first frequency resource, the second frequency resource and the third frequency resource. Assuming that the railway radio network and the other radio network have the same radio access standard, the minimum train frequency resource 260 for safe train operation must be reserved for the train, and the fourth radio frequency network is the minimum frequency resource necessary for other radio communication networks. Allocating the frequency resources 240 so as to perform the tasks that must be performed for network operations in each communication network, and allocates the frequency resources, and allocates appropriate frequency resources when the event occurs in each communication network of the common frequency resources 250, the remaining frequency domains. We present a method for providing frequency resources according to an algorithm. Such a mechanism can use a common network with other wireless networks while providing the necessary communication resources for safe train operation in the railway network. That is, due to the interworking with other communication networks, it does not affect the safe operation of the train operated by the railway wireless communication network at all. Therefore, limited frequency resources can be efficiently utilized while maintaining reliability and safety.

As described above, the frequency allocation method and apparatus according to the present invention may not be limitedly applied to the configuration and method of the embodiments described as described above, but the embodiments may be modified in various ways so that various modifications may be made. Or some may be selectively combined.

100; Frequency allocation device
110; Allocation
111; A first allocating unit 112; Second allocation unit
113; Third allocating unit 114; Fourth allocation unit
120; Synchronizer
1, 21a, 22a; First base station 2, 22a, 22b; 2nd base station
10a, 11a, 12a; First coverage 10b, 11b, 12b; 2nd coverage
10c; Double coverage
30a; First relay station 30b; 2nd relay station
40a; First switching center 40b; Second exchange
200a; First band 200b; 2nd band
200c; 1st band and 2nd band common
210; First frequency resource 220; 2nd frequency resource
230; Third frequency resource 240; Fourth frequency resource
260; Train frequency resources
260; Common frequency resources

Claims (12)

In the frequency band allocation method of the first base station and the second base station having the same frequency band and forming a double cell coverage,
Allocating a first frequency resource (RB) for a first purpose in a first band, which is a frequency band of the first base station;
Allocating a virtual second frequency resource that is different from a first frequency resource in the first band and to reserve the first purpose;
Allocating a third frequency resource in a second band which is a frequency band of the second base station; And
A synchronization step of sharing and controlling the time point of the transmission signal of the first base station and the second base station,
The third frequency resource is the same frequency band as the second frequency resource and is for the first purpose;
The synchronization step
The transmission time of the control signals is shared and controlled between the base stations so that the control signal A transmitted from the first base station and the control signal B corresponding to the control signal A transmitted from the second base station are sent in the same frequency domain. Frequency band allocation method, characterized in that. The method according to claim 1,
After allocating the third frequency resource,
A fourth frequency in the same band of the first band and the second band that is different from the first frequency resource, the second frequency resource, and the third frequency resource and for a second purpose different from the first purpose; And allocating resources, respectively. delete The method according to claim 1,
The second frequency resource is,
And having the same capacity as the first frequency resource. The method according to claim 1,
The first object is,
And the first base station and the second base station simultaneously transmit signals and control the moving object. The method according to claim 1,
The frequency of the first base station and the second base station,
A frequency band allocation method, characterized in that the railway frequency. In the frequency band allocation apparatus of the first base station and the second base station having the same frequency band and forming a double cell coverage,
A first allocator for allocating a first frequency resource for a first purpose in a first band which is a frequency band of the first base station;
A second allocator which is different from a first frequency resource in the first band and allocates a virtual second frequency resource to reserve the first purpose;
A third allocator for allocating a third frequency resource in a second band which is a frequency band of the second base station; And
Includes a synchronization unit for sharing and controlling the time point of the transmission signal of the first base station and the second base station,
The third frequency resource is the same frequency band as the second frequency resource and is for the first purpose;
The synchronization unit
The transmission time of the control signals is shared and controlled between the base stations so that the control signal A transmitted from the first base station and the control signal B corresponding to the control signal A transmitted from the second base station are sent in the same frequency domain. Frequency band allocation device, characterized in that. The method according to claim 7,
A fourth frequency in the same band of the first band and the second band that is different from the first frequency resource, the second frequency resource, and the third frequency resource and for a second purpose different from the first purpose; And a fourth allocation unit for allocating resources, respectively. delete The method according to claim 7,
The second frequency resource is,
And a frequency band allocator having the same capacity as the first frequency resource. The method according to claim 7,
The first object is,
And the first base station and the second base station simultaneously transmit signals and control the moving object. The method according to claim 7,
The frequency of the first base station and the second base station,
A frequency band allocation device, characterized in that the railway frequency.

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