KR101802076B1 - Method of supporting hand-over in ultra wide area wireless backhaul network, and apparatus performing the same - Google Patents

Abstract

Disclosed is a method of supporting a handover in a ultra wide area wireless backhaul network, and an apparatus performing the same. An operating method is disclosed. A method for supporting a handover in a ultra wide area wireless backhaul network according to an embodiment includes a step of generating wide-area beams corresponding to antenna arrays in a service area using the antenna arrays including antennas, respectively; a step of generating fine beams in each of the wide beams through beamforming based on the antennas, a step of managing at least one of the location information, signal strength, and RRC message of an access point for each of the wide beams for at least one of an handover between the wide-area beams and a handover between the fine beams generated in each of the wide-area beams. It is possible to provide stable service to a user.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for supporting handover in a wireless broadband backhaul network, and a device for performing the handover in a wireless broadband backhaul network.

The following embodiments relate to a handover support method in a super wide area wireless backhaul network and an apparatus for performing the same.

In the existing communication system, since the transmission / reception power of the base station providing the service to the mobile user is limited, the area that can be supported by one base station is limited. At this time, the mobile user is not fixed in one area but wants to continuously receive the service, and always finds the best base station to receive services such as call, data transmission and reception at the current location. Accordingly, the existing communication system provides a service to a mobile user by installing a plurality of base stations in a service area. The mobile user continuously monitors the strength of the signal of the neighbor base station as well as the base station providing the service while moving, and hand-over the signal to the base station having the highest signal strength. A base station providing a service to a mobile user before handover is referred to as a service base station, and a cell corresponding to a service base station is referred to as a source cell. A base station providing a service to a mobile user after completion of a handover is referred to as a target base station, and a cell corresponding to a target base station is referred to as a target cell.

In existing communication systems, a plurality of base stations are closely installed in order to meet the explosive use of data in urban areas. Accordingly, when a mobile user moves within a city, a service becomes unstable or disconnected due to a ping-pong phenomenon in a handover process for a mobile user. Such a ping-pong phenomenon usually occurs at the edge of a cell, and occurs when signals transmitted from both base stations are similar in size. Even if a plurality of base stations are closely installed, mobile users are not provided with appropriate services due to the ping-pong phenomenon.

Further, in the existing communication system, since the coverage range of each base station is fixed separately from the moving speed of the mobile access point, the access point moving at a high speed becomes difficult to receive a stable service due to an excessive handover increase.

Embodiments can provide a technique for providing stable service to a user by preventing a handover ping-pong phenomenon in a super wide area wireless backhaul network and minimizing the number of handovers.

According to an exemplary embodiment of the present invention, there is provided a method of supporting handover in a wireless broadband backhaul network, the method comprising: generating wide-area beams corresponding to the antenna arrays in a service area using antenna arrays each including antennas; Generating fine beams on each of the wide beams through beamforming based on the beamforming of the beams, and performing handover for at least one of handover between the wide beams and handover between the fine beams generated in each of the wide beams, And managing at least one of the location information of the point, the signal strength, and the RRC message.

Each of the wide-area beams is assigned to a different time / frequency resource, and the fine beams generated in each of the wide-area beams may be assigned to the same time / frequency resource.

In the method, when there is an access point entering any one of the wide-area beams, a target fine beam to be handed over among the fine beams generated in any one of the access paths entering the one of the wide- And the like.

The method comprising the steps of: when the access point entering any one of the wide-area beams enters another one of the wide-area beams, transmitting position information, signal strength, and RRC message of the access point, And may further comprise managing in one.

The method may further comprise controlling the coverage of each of the wide-area beams according to the traffic density in the wide-area beams for the handover.

The support range may be determined by the moving speed of the access point located in each of the wide-area beams.

A wireless backhaul switch for supporting handover in a super-wide area wireless backhaul network according to an exemplary embodiment includes antenna arrays each including antennas and a wide-area beam corresponding to the antenna arrays in a service area using the antenna arrays, At least one of the handover between the wide-area beams and the handover between the fine beams generated in each of the wide-area beams, at least one of the handovers between the wide- A signal strength, and an RRC message for each wide beam for each of the plurality of access points.

Each of the wide-area beams is assigned to a different time / frequency resource, and the fine beams generated in each of the wide-area beams may be assigned to the same time / frequency resource.

Wherein the controller is configured to, when there is an access point that has entered any one of the wide-area beams, a target fine beam to be handed over from among the fine beams generated in any one of the access paths, Can be specified.

Wherein the controller is configured to transmit the location information, the signal strength, and the RRC message of the access point, which has entered one of the one or more access points, to another one of the wide- You can manage from one.

1 is a schematic block diagram of a wireless backhaul network system according to an embodiment of the present invention.
2 is a view for explaining an example of the fine beam coverage generated by the wireless backhaul switch shown in FIG.
FIG. 3 is a view for explaining a detailed beam generated by the wireless backhaul switch shown in FIG. 1. FIG.
4A to 4D are views for explaining an example in which the wireless backhaul switch shown in FIG. 1 supports handover in a wireless backhaul network.
5 is a view for explaining another example in which the wireless backhaul switch shown in FIG. 1 supports handover in a wireless backhaul network.
Figure 6 is a schematic block diagram of the wireless backhaul switch shown in Figure 1;

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are presented for the purpose of describing embodiments only in accordance with the concepts of the present invention, May be embodied in various forms and are not limited to the embodiments described herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the embodiments according to the concepts of the present invention to the specific disclosure forms, but includes changes, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms " comprises ", or " having ", and the like, are used to specify one or more of the features, numbers, steps, operations, elements, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

FIG. 2 is a view for explaining an example of detailed beam coverage generated by the wireless backhaul switch shown in FIG. 1, and FIG. 3 is a view for explaining an example of detailed beam coverage generated by the wireless backhaul switch shown in FIG. 1 is a view for explaining a detailed beam generated by the wireless backhaul switch shown in Fig. 1. Fig.

1 to 3, a wireless backhaul network system 10 may include a wireless backhaul switch 100 and one or more access points 200.

The wireless backhaul network system 10 may be a system based on a small cell based ultra wide area and ultra high capacity wireless backhaul technology. That is, the wireless backhaul network system 10 may be referred to as an ultra wide area wireless backhaul network.

The wireless backhaul switch 100 may comprise a plurality of antenna arrays, e.g., a first antenna array to an nth antenna array. Each of the plurality of antenna arrays may comprise a plurality of antennas (or antenna elements).

The wireless backhaul switch 100 can support handover within a wireless backhaul network with a two-stage beamforming structure.

In a first step, the wireless backhaul switch 100 may generate wide-area beams WP-1 to WP-n in the form of analog beamforming. The wireless backhaul switch 100 can generate wide-area beams WP-1 to WP-n corresponding to a plurality of antenna arrays in a service area using a plurality of antenna arrays each including a plurality of antennas have.

For example, the first wide area beam WP-1 corresponds to the first antenna array, the second wide area beam WP-2 corresponds to the second antenna array, and the third wide area beam WP- And the n th wide beam (WB-n) may correspond to the nth antenna array.

The service coverage area may be an area where the access point 200 can be located to receive service from a wireless backhaul switch 100 serviceable (or communicable) area and / or a wireless backhaul switch 100.

In a second step, the wireless backhaul switch 100 may generate fine beams in each of the wide-area beams WP-1 to WP-n in the form of digital beamforming. The wireless backhaul switch 100 may generate fine beams at each of the wide beams WP-I through WP-n through beamforming based on a plurality of antennas included in each of the plurality of antenna arrays.

For example, the wireless backhaul switch 100 may generate fine beams at the first wide beam WP-1 through beamforming based on a plurality of antennas included in the first antenna array. The wireless backhaul switch 100 may generate fine beams at the second wide beam WP-2 through beamforming based on the plurality of antennas included in the second antenna array. The wireless backhaul switch 100 may generate fine beams at the third wide beam WP-3 through beamforming based on the plurality of antennas included in the third antenna array. The wireless backhaul switch 100 may generate fine beams on the n th wide beam WP-n through beamforming based on a plurality of antennas included in the nth antenna array.

As shown in FIG. 2, in each of the wide-area beams, a plurality of fine beams with a narrow beam width can be generated. Each of the plurality of fine beams may correspond to each of the plurality of cells. Each of the plurality of cells formed through each of the plurality of fine beams may be a LoS (Line of Sight) or a Non-Line of Sight (NLoS) environment.

Further, as shown in Fig. 3, the fine beam can be emitted by generating a beam pattern only in a specific direction. The fine beam in FIG. 3 is generated through a linear antenna array including K antennas, and the 3dB bandwidth can be 2.38 degrees and the first null beam width (FNBW) can be 5.8 degrees. But the present invention is not necessarily limited thereto, and the fine beam can be generated through various antenna arrays to have various 3 dB bandwidth and FNBW.

Each of the wide beams WP-1 to WP-n is assigned to different time / frequency resources and the fine beams generated in each of the wide beams WP-1 to WP-n are assigned to the same time / . That is, the fine beams generated in the different wide beam are assigned to different time / frequency resources, and the fine beams generated in the same wide beam can be assigned to the same time / frequency resource.

When the access point 200 enters one of the wide-area beams WP-1 to WP-n, for example, the first wide beam WP-1, the access point 200 transmits the first wide- The service can be provided from the wireless backhaul switch 100 through the plurality of fine beams generated in the WP-1.

For example, the wireless backhaul switch 100 supports a very high capacity of Tbps in the ultra-wide range of several tens to several hundreds of km ² through the hundreds of fine beams generated in the wide-area beams WP-1 to WP-n, And may provide services to the point 200. At this time, one fine beam can cover thousands to tens of m ² .

The access point 200 may include a plurality of antennas and may perform transmit beamforming and receive beamforming through a plurality of antennas.

The access point 200 may be a fixed access point or a mobile access point. For example, the fixed access point may be located anywhere that can be mounted in an outdoor (e.g., a streetlight, a traffic light, a telephone box, etc.) and / or indoors (e.g., a building, a company, a home, etc.). The mobile access point may be located (or mounted) in any means that can be moved (e.g., a vehicle, a bus, a bicycle, a subway, etc.).

The access point 200 in the cell connected to the wireless backhaul switch 100 may support access network services to at least one terminal in the cell. A mobile terminal (MS), a mobile terminal (MT), a user terminal (UT), a wireless terminal An access terminal (AT), a subscriber unit, a subscriber station (SS), a wireless device, a wireless communication device, a wireless transmit / receive unit (WTRU) Node, mobile, or the like.

The wireless backhaul switch 100 performs handover between the wide-area beams WP-1 to WP-n and fine beams generated in the wide-area beams WP-1 to WP-n through the two- And at least one of handover.

The handover between the wide beams WP-1 to WP-n implies hard handover and the handover between the fine beams generated in each of the wide beams WP-1 to WP-n is a soft handover It can mean. Handover between the wide-area beams WP-1 to WP-n is performed in the form of handover between heterogeneous frequencies, and the handover between fine beams generated in each of the wide-area beams WP-1 to WP- Frequency handover.

The wireless backhaul switch 100 is configured for at least one of handover between the wide beams WP-1 to WP-n and handovers between the fine beams WP-1 to WP-n generated in each of the wide- And may manage at least one of movement information, signal strength, and RRC (Radio Resource Control) messages of the access point 200 for each wide beam. The movement information may include at least one of position information and velocity information of the access point 200. [

At this time, the access point 200 managed for each wide beam may refer to an access point that enters an access point and / or a wide-area beam included in each of the wide-area beams WP-1 to WP-n.

Hereinafter, the operation in which the wireless backhaul switch 100 supports the handover in the wireless backhaul network will be described in detail.

4A to 4D are views for explaining an example in which the wireless backhaul switch shown in FIG. 1 supports handover in a wireless backhaul network.

4A to 4D, for convenience of description, the access point 200 enters the first wide-area beam WP-1 out of the wide-area beams WP-1 to WP-n and then enters the second wide- -2). ≪ / RTI > It is also assumed that seven fine beams are generated in each of the wide-area beams WP-1 and WP-2.

4A to 4D, the wireless backhaul switch 100 is configured to allow the access point 200 to access the access point 200 based on the pre-traffic information when the access point 200 enters the first wide beam WP- The movement route can be predicted.

The wireless backhaul switch 100 can acquire the pre-traffic information because it acquires and manages the movement information of the access point 200 in advance in the first wide-area beam WP-1. For example, the wireless backhaul switch 100 predicts the location of the access point 200 moving along a certain path and estimates the moving speed of the access point 200 according to the amount of road traffic by time zone. That is, the wireless backhaul switch 100 can predict the movement path of the access point 200 in consideration of the expected position and speed of the access point 200.

The wireless backhaul switch 100 can manage at least one of the movement information, the signal strength, and the RRC message of the access point 200 through the first wide beam WP-1. For example, the movement information may include at least one of position information and velocity information of the access point 200. [

In addition, the wireless backhaul switch 100 continuously transmits at least one of the movement information, the signal strength, and the RRC message of the access point 200 when the access point 200 is within the range of the first wide beam (WP-1) You can update it.

The wireless backhaul switch 100 is configured to perform a handover corresponding to the expected travel path of the access point 200 based on information collected via the first wide area beam WP-1, e.g., Target cell millimeter beams B1 to B3 can be designated.

For example, the wireless backhaul switch 100 designates the target fine beam B1 to be handed over corresponding to the anticipated movement path of the access point 200 at the first time point T1, A target fine beam B2 to be handed over corresponding to the anticipated movement path of the access point 200 is designated and at the third time point T3, (B3).

That is, the wireless backhaul switch 100 switches from the time when it enters the first wide-area beam WP-1 to the time when the first wide-area beam WP-1 leaves the first wide-area beam WP- Target fine beams B1 to B3 to be handed over can be continuously designated.

When the wireless backhaul switch 100 enters the second wide area beam WP-2 from the first wide area beam WP-1, the wireless backhaul switch 100 moves the access point 200 managed by the first wide area beam WP- Information, signal strength, and RRC message in the second wide-area beam WP-2.

In the existing communication system, when a handover event occurs, the target cell receives an RRC message indicating that the cell change is completed in the access point that has completed the handover, and the cell change must be updated in the PDCP (Packet Data Convergence Protocol) The over process is complete. As described above, the conventional communication system takes a long time to detect the completion of the handover, and if the RRC message checking process between the access point and the target cell is delayed, the service itself may become impossible.

The single wireless backhaul switch 100 manages (or monitors) at least one of movement information, signal strength, and RRC (Radio Resource Control) messages of the access point 200 for each wide beam at a time, .

However, the wireless backhaul switch 100 may be configured such that the wide-area beams WP-1 to WP-n (n-1) According to the expected movement path of the access point 200 entering the wide area beam, the target fine beams to be handed over are selected from the fine beams generated in one wide area beam, The ping-pong phenomenon can be prevented.

That is, the wireless backhaul switch directly manages the RRC message required for the handover and can directly transmit the RRC message to the access point, so that the ping-pong phenomenon can be prevented by promptly responding to handover.

5 is a view for explaining another example in which the wireless backhaul switch shown in FIG. 1 supports handover in a wireless backhaul network.

5, the wireless backhaul switch 100 performs a handover between the wide-area beams WP-1 to WP-n and a handover between the fine beams generated in the wide-area beams WP-1 to WP- The support range of each of the wide-area beams WP-1 to WP-n can be controlled according to the traffic density in the wide-area beams WP-1 to WP-n in order to support at least one of them.

The access point 200 moves in various environments according to changes in space and time. When there are many vehicles on the road side such as a commute time or a weekend, the number of the access points 200 having a fast moving speed decreases, but the traffic density is high, so that the amount of the service to be supported for the access point 200 increases.

Conversely, in an environment where traffic is smooth and there are not many vehicles on the road, the probability of the access point 200 having a high moving speed may be high. Although the traffic density is low, a large number of handovers may occur in the access point 200 moving at a high speed.

That is, the wireless backhaul switch 100 needs to consider the mobility of the access point 200 in order to stably support the handover to the access point 200.

When the wireless backhaul switch 100 adjusts the support range of each of the wide-area beams WP-1 to WP-n according to the traffic density in the wide-area beams, the adjusted wide-area beams WP-1 to WP-n The support range of each fine beam can also be adjusted corresponding to the support range of FIG. That is, as the support range of the wide beam increases, the support range of each fine beam also increases, and when the support range of the wide beam decreases, the support range of each fine beam can also decrease.

At this time, the support range of each of the wide-area beams WP-1 to WP-n controlled by the wireless backhaul switch 100 corresponds to the access point 200 located in each of the wide beams WP-1 to WP-n, As shown in FIG.

That is, the support range of the wide-area beams WP-1 to WP-n is increased by the moving speed of the access point 200 moving at high speed, and the support range of each fine beam is also increased, . However, as the support range becomes infinitely large, the number of handovers can be reduced. However, since the power per unit area is reduced and stable service becomes impossible, the wireless backhaul switch 100 can support the network capacity less than a certain threshold You can limit the size of the range.

As shown in FIG. 5, when the traffic density is high, for example, in the case of a highway and a suburban area, since the density of the access point is low and moves at a high speed, the wireless backhaul switch 100 moves the moving speed of the access point 200 The loss of frequent handover (for example, a signal interruption phenomenon in a handover process) can be minimized. Further, when the traffic density is low, for example, in the case of a downtown area, since the density of the access point 200 is high and moves at a slow speed, the wireless backhaul switch 100 can reduce the power per unit area ) To minimize the scope of support.

Figure 6 is a schematic block diagram of the wireless backhaul switch shown in Figure 1;

Referring to FIG. 6, the wireless backhaul switch 100 may include a MIMO antenna 110 and a controller 130.

The MIMO antenna 110 may comprise a plurality of antenna arrays, e.g., a first antenna array to an nth antenna array. Each of the plurality of antenna arrays may comprise a plurality of antennas (or antenna elements).

The control channel 130 can support handover in a wireless backhaul network with a two-stage beamforming structure.

The controller 130 shown in FIG. 6 can be applied to the handover support contents of the wireless backhaul switch 100 described with reference to FIG. 1 to FIG. 5 as it is, and thus a detailed description thereof will be omitted.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA) , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command 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 to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (10)

A method for supporting a handover in an ultra-wide area wireless backhaul network,
Generating wide-area beams corresponding to the antenna arrays in the service area using antenna arrays each including the antennas;
Generating fine beams in each of the wide beams through beamforming based on the antennas; And
Managing at least one of movement information, signal strength, and RRC messages of the access point for each wide beam for at least one of handover between the wide-area beams and handover between fine beams generated in each of the wide-area beams,
Lt; / RTI >
When there is an access point entering any one of the wide-area beams, target fine beams to be handed over are designated from among the detailed beams generated in any one of the access paths entering the one of the access points entering the one step
Further comprising:
Wherein the movement information is location information and speed information of the access point, and the expected movement route is predicted according to the movement information and the road traffic amount by time zone.
The method according to claim 1,
Wherein each of the wide-area beams is assigned to a different time / frequency resource, and the fine beams generated in each of the wide-area beams are assigned to the same time / frequency resource.
delete The method according to claim 1,
Signal strength, and RRC message of the access point which has been managed by any one of the wide area beams, when the access point enters one of the wide-area beams, Step
Further comprising the step of:
The method according to claim 1,
Controlling the support range of each of the wide-area beams according to the traffic density in the wide-area beams for the handover
Further comprising the step of:
6. The method of claim 5,
Wherein the support range is determined by a moving speed of an access point located in each of the wide-area beams.
A wireless backhaul switch for supporting handover in a wireless broadband backhaul network,
Antenna arrays each comprising an antenna; And
Generating wide beams corresponding to the antenna arrays in the service area using the antenna arrays, generating fine beams in each of the wide beams through beamforming based on the antennas, Signal strength, and RRC message for each wide beam for at least one of handover between the overhead beams and the overhead beams generated in each of the overhead beams and the wide beams, and managing at least one of the wide- A controller for designating target fine beams to be handed over from among the fine beams generated in any one of the access paths corresponding to the expected movement path of the access point entering the one of the access points,
Lt; / RTI >
Wherein the movement information is location information and speed information of the access point, and the expected movement route is predicted according to the movement information and the road traffic amount by time zone.
8. The method of claim 7,
Wherein each of the wide-area beams is assigned to a different time / frequency resource, and the fine beams generated in each of the wide-area beams are assigned to the same time / frequency resource.
delete 8. The method of claim 7,
The controller comprising:
Signal strength, and RRC message of the access point which has been managed by any one of the wide area beams, when the access point enters one of the wide-area beams, Wireless backhaul switch.

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