KR20130064388A - Digital unit handover apparatus and method thereof - Google Patents

Abstract

PURPOSE: A digital device handover device and a method thereof are provided to process data generated in a communication device connected to a digital device by distributing the data to a plurality of the digital devices. CONSTITUTION: RU(Radio frequency Units)(508,510) process data received or transmitted from a terminal device within a base station. A plurality of DU(Digital Units)(502,504) is connected to the RU. The plurality of DU processes the signal of the data. A switch unit(506) switches the RU with the DU according to a predetermined control signal. A handover server(500) controls the switch unit according to the set condition in order to switch the DU with the RU. [Reference numerals] (500) Handover server; (502,504) Digital unit(DU); (506) Switch unit; (508,510) Radio frequency unit(RU)

Description

DIGITAL UNIT HANDOVER APPARATUS AND METHOD THEREOF

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handover of a base station digital device in a mobile communication system. Particularly, the present invention relates to a cell or sector connected to a communication unit (RU: RF unit) during configuration of a base station equipment of a mobile communication system. When a digital device that handles communication data from a terminal device located in an area (DU: Digital Unit) integrates and manages multiple digital devices with a cloud function and a capacity limit occurs in one digital device, By distributing the data generated by the communication device connected to the digital device to a plurality of digital devices having resource margins through a switch, the base station can process the data of the increased sector without additional digital device expansion. The present invention relates to a handover device and a method for a digital device.

In the conventional cellular-based wireless communication, one base station NodeB is responsible for communication of UEs located in an area of one cell or sector, and each base station is configured to process communication data of corresponding terminals. It includes a communication device (RU) and digital device (DU) equipment connected thereto.

Digital devices such as the above generally convert the signals transmitted from the communication device and the system part that is in charge of control between the digital device and the communication device, and send them to the core network. In order to decode and convert the IP signal transmitted from core network to a signal for transmission to a communication device, it can be divided into a part responsible for transmission.

In addition, the communication device may be configured with a functional block as shown in FIG. 1. That is, the communication device 100 receives an IF signal 102 corresponding to three sectors transmitted from the digital device, and transmits the IF signal 102 to the antenna via the PA and a filter.

In the case of one digital device, processing for a plurality of sectors in which one NodeB is involved may be configured, and communication devices and digital devices allocated for each sector may be spaced apart from each other. The processing capacity of each sector can be expanded by additional channel card additionally installed in one digital device or by additional digital device in the case of exceeding the channel card capacity.

FIG. 2 illustrates a concept in which an additional digital device is added to a channel card to perform data processing of the exceeded capacity when the capacity of one digital device is exceeded.

That is, as shown in FIG. 2, when the digital device exceeds the limit capacity that one digital device can handle, a specific transmission capacity of the terminal is increased through the purchase of an additional digital device to process the insufficient digital processing capacity. In order to process data of a cell or to separate a corresponding sector through cell planning, the added digital device processes the sector data of the separated area.

Korean Patent Laid-Open Publication No. 2006-0024791 discloses a technique for wireless communication components and methods for a large number of system communications.

However, the addition of such a digital device requires an additional cost from the network operator's point of view, and even if additional cell planning is performed, there is a cost from an operational point of view.

Accordingly, the present invention integrates and manages a plurality of digital devices in a cloud function for a digital device that is connected to a communication device of a base station equipment configuration of a mobile communication system and processes communication data from a terminal device located in an area of a cell or sector. When a capacity limit occurs in one digital device, the data generated by the communication device connected to the digital device is distributed to a plurality of digital devices having resource margin through a switch, thereby processing an increased sector without additional digital device expansion at the base station. To provide a handover system, apparatus and method of a digital device that can process the data of the.

The present invention described above is a handover device of a base station digital device, comprising: a communication device for processing data transmitted or received from a terminal device in a base station; a plurality of digital devices connected to the communication device to perform signal processing on the data; A switch unit for switching and connecting the communication device and the plurality of digital devices according to a predetermined control signal; and a handover for controlling the switch unit according to a predetermined condition and switching one of the plurality of digital devices with the communication device. Include a server.

In addition, the handover server measures the load of the default digital device connected to the communication device by default, and when the data processing capacity of the default digital device is exceeded, the handover server controls the switch unit so that the excess of the plurality of digital devices is exceeded. And connecting the communication device with an alternative digital device having a resource capable of processing data.

The handover server measures a load state of the default digital device when the terminal device initially connected to the communication device by default connected to the communication device transmits a connection request again in an idle state or an RRC-connected state. When the connection request cannot be processed, the switch unit is controlled to connect the communication device with an alternative digital device having a resource capable of processing the excess data among the plurality of digital devices.

The handover server may be configured to control management parameters of the terminal device to be transmitted from the default digital device to the replacement digital device when the replacement digital device and the communication device are connected by switching.

The handover server may search for a digital device corresponding to the type of data from the terminal device when the digital device to process the data is set in advance according to the type of data transmitted or received from the terminal device. And controlling the switch unit to connect the communication device with the searched digital device.

The handover server may provide management parameter information of a terminal device connected to the communication device to one alternative digital device selected from the plurality of digital devices, and provide the communication device with the data from the terminal device. And control to process the data at the same time as the default digital device to which the default is connected.

The digital apparatus may be connected to the communication apparatus to perform signal processing on the data, transmit the data to a core network of a mobile communication system, and transmit a signal received from the core network to the communication apparatus.

The present invention also provides a handover method for a digital device of a base station, the method comprising: receiving a connection request from a terminal device through a communication device of the base station; and a default digital device connected to the communication device by default when the connection request is received. Checking whether the data processing capacity of the system is exceeded, searching for a replacement digital device capable of processing the excess data when the capacity of the default digital device is exceeded, connecting the replacement digital device to the communication device, And processing the connection request of the terminal device.

The present invention also provides a handover method for a digital device of a base station, the method comprising: transmitting a connection request again by an arbitrary terminal device in an idle state or an RRC-connected state through a communication device of the base station, and receiving the connection request. And determining a load state of a default digital device connected to the communication device by default, and when the measurement result indicates that the default digital device cannot process the connection request, an alternative digital device capable of processing the connection request. Retrieving and connecting the alternate digital device and the communication device to process the connection request.

In the processing of the access request, management parameter information for the terminal device is transmitted from the default digital device to the replacement digital device.

The present invention also provides a handover method for a digital device of a base station, the method comprising: receiving data transmitted or received from a terminal device through a communication device of the base station, and analyzing the type of the data to process the data; Searching for a digital device; and connecting the searched digital device to the communication device to process data of the terminal device.

The present invention also provides a handover method for a digital device of a base station, the method comprising: receiving data transmitted or received from a terminal device through a communication device of the base station; and a default digital device which is connected to the communication device by default. And providing management information of the terminal device to an alternative digital device replacing the default digital device, and processing data of the terminal device together with the default digital device in the alternative digital device. Include.

The present invention relates to a handover method of a digital device in a mobile communication system, comprising: a plurality of digital devices for a digital device that is connected to a communication device during configuration of a base station and processes communication data from a terminal device located in an area of a cell or sector Integrated management with the cloud function, if a capacity limit occurs in one digital device, the base station at the base station by distributing the data generated from the communication device connected to the digital device to a plurality of digital devices with a resource margin through the switch There is an advantage in that it is possible to process the data of the increased sector without adding additional digital devices.

1 is a circuit diagram of a communication device of a conventional mobile communication system base station;
2 is a conceptual diagram of the expansion of the digital device when the capacity of the conventional base station is insufficient;
3 is a diagram illustrating a network configuration for handover of a digital device of a base station according to an embodiment of the present invention;
4 is a conceptual diagram of a digital device handover of a base station according to an embodiment of the present invention;
5 is a block diagram of a digital device handover apparatus of a base station according to an embodiment of the present invention;
6 is a flowchart illustrating a digital device handover operation control of a base station according to an embodiment of the present invention;
7 is a flowchart illustrating a digital device handover operation control of a base station according to another embodiment of the present invention;
8 is a flowchart illustrating a digital device handover operation control of a base station according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the present invention. In the following description of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

3 illustrates a network configuration of a handover system for a digital device of a base station according to an embodiment of the present invention.

Hereinafter, in the description of the present invention, an operation in a cloud RAN in which a digital device and a communication device are operated separately will be described. That is, the application of the present invention may be applied regardless of whether the digital device and the communication device are spatially separated, but for convenience of description, the following description will be given using a cloud form in which the digital device and the communication device are separated as follows. Shall be.

Data transmitted through the core network is processed to be delivered to a specific communication device 306, 308, 310 through a collection 300 of digital devices gathered at the same place, and conversely, the specific communication device 306, 308, The data received at 310 is passed to the collection point 300 of the digital device via the DU-RU interface 304 for processing and delivery to the core network.

In such a structure, when the processing capacity of the digital device that processes data of any communication device 306, 308, 310 is insufficient, resources corresponding to the insufficient capacity can be borrowed. At this time, the above-mentioned resources may be all resources on an access network used for wireless transmission, for example, and a method of borrowing and using resources may be defined as resource pooling.

FIG. 4 illustrates a concept of an operation of processing data by handing over to another digital device having a resource when the capacity of the digital device is exceeded according to an embodiment of the present invention.

The present invention provides a method of directly or indirectly connecting data that has been processed in a specific digital device through a direct or indirect connection (indirect connection means connection through a switch) between any digital devices (DUs) that are hardware distinct. It is to be processed by another alternative digital device or simultaneously with another digital device. That is, data generated in one communication device RU may be distributed to a plurality of digital devices as appropriate through a switch, and then transmitted and processed. In addition, one digital device may be configured to process data of a plurality of digital devices located at different locations.

In more detail with reference to Figure 4, there is a RU (RF Unit) A (400), RU B (404) equipment, such as communication devices located in each region, each RU A (400) and RU B (404) Assume that is configured to govern three sectors. Conventionally, each of RU A 400, RU B 402 equipment, and digital unit (DU) A 402 and DU B 406 equipment, which are digital devices, is mapped 1-1, and each DU A is mapped. 402, the RU A 400, which is in charge of the DU B 406 equipment, is responsible for the α, β, and γ sectors of the RU B 404, and the resources responsible for each sector as shown in the DU A 402 ( The resources can be efficiently divided and used between resources to fit each sector's load by resource pooling.

It is proposed in the present invention that the remaining resources of the DU A 402 are allocated to the RU B 404 when the resources of the DU B 406 become insufficient to cover the processing capacity of the RU B 404, To be used for processing. For example, when the number of terminal units of the? Sector of the RU B 404 increases or the amount of data to be transmitted increases, and the resources of the DU B 406 become insufficient, a part of the processing data of the? Sector of the RU B 404 To utilize the remaining resources of the DU A 402 connected via the switch 408.

FIG. 5 illustrates a detailed configuration of a handover apparatus for a digital apparatus of a base station according to an embodiment of the present invention. The handover apparatus of the present invention includes a handover server 500 and a digital apparatus (DU). Digital Units (502, 504), switch (switch) 506, communication unit (RU: RF Unit) (508, 510) and the like.

Hereinafter, the operation of each component of the handover apparatus of the present invention will be described in detail with reference to FIG.

First, the communication devices 508 and 510 process communication data transmitted and received from a terminal device such as a mobile phone existing in the base station as one of the equipment constituting the base station of the mobile communication system. In addition, after receiving the IF signal 102 corresponding to three sectors transmitted from the digital devices 502 and 504, which are connected to the other devices constituting the base station, the digital devices 502 and 504, the signal processing is performed. Then, the antenna is transmitted to the terminal device through an antenna.

The digital devices 502 and 504 process communication data from a terminal device applied from the communication devices 508 and 510. The digital devices 502 and 504 convert a signal transmitted from the communication devices 508 and 510 and convert the signal into a core. It decodes to send to the core network, and conversely performs signal processing such as converting an IP signal transmitted from the core network into a signal for transmission to the communication devices 508 and 510.

The switch unit 506 is a device for switching the plurality of digital devices 502 and 504 and the communication devices 508 and 510. The digital device 502 whose data processing capacity is exceeded under the control of the handover server 500. Instead of switching between the digital devices 502 and 504 having sufficient resources, the communication devices 508 and 510 are switched.

The handover server 500 manages the resource status of the plurality of digital devices 502 and 504, and exceeds the capacity of the digital devices 502 and 504 to process communication data from the connected communication devices 508 and 510, respectively. ), Search for the digital devices 502 and 504 having free resources to process the excess capacity data, and control the switch unit 506 to free up the communication devices 508 and 510. Handover to the digital devices 502 and 504 to allow excess capacity of data to be processed.

Generally, the concept of handover is that when a terminal device moves beyond the cell boundary, for example, from the cell 1 area to the cell 2 area, a difference in the received signal between two cells of the RF stage occurs, It can be considered that the UE moves between two cells using different FAs. In both cases, it can be considered that the handover is initiated due to the change of the RF stage. The present invention proposes a handover of digital devices 502 and 504 that is initialized due to insufficient capacity of the digital device rather than being initialized to such an RF stage.

The handover of such digital devices 502 and 504 is, for example, 1) when the terminal device is turned on from an off state and attempts initial network access. It may be the case that an initial network connection is attempted by an alternative digital device (alternate DU) rather than a digital device (default DU).

In addition, 2) it may be the case that an idle terminal device receives a paging signal from an alternative digital device, or the terminal device generates a call to process a call through the alternative digital device.

In addition, 3) when the terminal device in the RRC connected state transmits a part of the control signal or a part of the data signal through the alternative digital device, 4) may use both the default digital device and the alternative digital device.

In this case, in all cases 1), 2), 3), and 4), the handover server 500 prevents the terminal device from recognizing whether the digital devices 502 and 504 are handed over, and the specific digital device 502. The controller 506 may recognize the overload on the 504, and control the switch unit 506 to hand over to other digital devices 502 and 504 having sufficient resources. Alternatively, the network device notifies the terminal device of a congestion state of the digital device 502, 504 of the network through a specific field or an RRC message in advance and recognizes the terminal device based on this information. ) May be initiated.

6 is a flowchart illustrating a handover operation control flow of a digital device in a handover device for a digital device of a base station according to an embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 5 and 6. FIG.

First, when a connection request is received from a terminal device existing in a sector controlled by a base station through a specific communication device 508 (S600), the handover server 500 connects to the default digital device 502 connected to the communication device 508. In step S602, it is checked whether or not the data processing capacity of the terminal is exceeded according to the connection request processing of the terminal apparatus.

That is, the handover server 500 checks whether the number of terminal devices in the RRC-connected or idle state currently managed by the default digital device 502 exceeds a threshold value Γ that can determine the excess of the data processing capacity. It is determined whether the connection request of the terminal device can be processed.

At this time, if the default digital device 502 determines that the data processing capacity is not exceeded according to the connection request processing of the terminal device, the handover server 500 requests the connection request of the terminal device to the default digital device 502. To process in (S606).

However, in contrast, when the default digital device 502 determines that the data processing capacity is exceeded according to the connection request processing of the terminal device, the handover server 500 has a relatively resource margin for the connection request of the terminal device. By searching for the replacement digital device 504 and controlling the switch unit 506 to connect the communication device 508 to the replacement digital device 504, the connection request processing for the terminal device is made in the replacement digital device 504. To help.

FIG. 7 is a flowchart illustrating a handover operation control flow of a digital device in a handover device for a digital device of a base station according to another embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 5 and 7. FIG.

First, when a connection request is received from a terminal device existing in a sector controlled by a base station through a specific communication device 508, the default digital device 502 connected with the communication device 508 is initially connected to the terminal device. Will be processed.

On the other hand, although the initial connection was processed by the default digital device 502 as described above, the default digital device 502 is no longer idle and may be caused by an increase in load or other factors of the default digital device 502 after the initial connection processing. The terminal device in the RRC-connected state may be in a state in which the connection request cannot be processed.

Accordingly, the handover server 500 checks the state of the default digital device 502 so that the default digital device 502 cannot process a connection request for the terminal device in the idle and RRC-connected states. Check whether it becomes (S700). The information on the state of the default digital device 502 may be recognized by the handover server 500 through a status report of the default digital device 502.

At this time, when the data processing capacity of the default digital device 502 is not exceeded (S702), the handover server 500 does not perform switching on the digital device, and continues to idle and the default digital device 502. The connection request to the terminal device in the RRC-connected state is processed (S704).

On the other hand, when the data processing capacity in the default digital device 502 is exceeded, and the terminal device in the idle and RRC-connected state can no longer be handled (S702), handover. The server 500 searches for an alternative digital device 504 that will handle the connection request on behalf of the default digital device 502 and paging the idle device and the terminal device in the RRC-connected state to the corresponding replacement digital device 504. And management parameters such as related data (S706).

Subsequently, the handover server 500 controls the switch unit 506 to connect the communication device 508 to the alternative digital device 504, thereby transferring the idle device and the RRC-connected terminal device from the alternative digital device 504. The connection request processing can be made (S708).

8 illustrates a flow of handover operation control of a digital device in a handover device for a digital device of a base station according to another embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 5 and 8. FIG.

Unlike the previous embodiment in which the alternative digital device performs the connection request according to the state of the default digital device, in the embodiment of FIG. 8, the default digital device and the alternative digital device are previously determined according to the type of data requested for processing from the terminal device. This section describes the operation to use them separately.

That is, the data is processed by setting a default digital device and an alternative digital device for each transmission burst unit of one terminal device, for example, RRC / MAC / Frame / subframe / OFDM symbol / antenna / RB transmission. It is. In this case, the switching cycle between the default digital device and the alternative digital device is faster than the two embodiments described above, and the load can be more adaptively distributed according to the state of the digital device.

First, the handover server 500 sets digital devices 502 and 504 to perform data type-specific processing on data requested for processing from a terminal device (S800).

Subsequently, when a data processing request is received from the terminal device, the handover server 500 checks the type of data requested for processing to check whether the data should be processed in the default digital device 502 (S802).

At this time, if the data requested to be processed from the terminal device is data set to be processed by the default digital device 502 (S804), the handover server 500 determines that the data requested to be processed from the terminal device is stored in the default digital device 502. To be processed (S806).

However, in contrast, when the data requested for processing from the terminal device is data set to be processed by the alternative digital device (S804), the handover server 500 controls the switch unit 506 to replace the communication device 508 with the alternative digital device. By connecting to 504, the data requested for processing from the terminal device is processed in the alternative digital device 504 (S808).

As described above, control / data A may be processed through the default digital device that handled the initial connection, control / data B may be processed through the alternate digital device, and in the case of an alternative digital device, the default digital for the terminal device. Since it must maintain the same state as the device, it can be defined as a duplicated digital device, and the default digital device and the replacement digital device maintain the same management parameter for the terminal device through constant information exchange. .

In another embodiment of the present invention, the same data may be simultaneously processed by the default digital device and the replacement digital device. Such a method may be used as a method for preventing interruption of processing or data interruption during handover of a digital device in the above-described embodiments.

As described above, the present invention provides a handover method of a base station digital device in a mobile communication system, wherein the digital device is connected with the communication device during the configuration of the base station equipment to process communication data from a terminal device located in an area of a cell or sector. In the case of capacity limitation in one digital device, the data generated by the communication device connected to the digital device is transferred to a plurality of digital devices with resource margin through a switch. By distributing and processing, the base station can process the data of the increased sectors without adding additional digital devices.

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

In the present invention, in the handover method of a base station digital device in a mobile communication system, it is possible to apply to a mobile communication system by processing data in an increased sector without adding digital device equipment of the mobile communication system.

500: handover server 502, 504: digital device (DU)
508, 510: communication unit (RU) 506: switch unit

Claims (12)

A communication device for processing data transmitted or received from a terminal device in a base station;
A plurality of digital devices connected to the communication device to perform signal processing on the data;
A switch unit for switching and connecting the communication device and the plurality of digital devices according to a predetermined control signal;
A handover server which controls the switch unit according to a predetermined condition and switches one of the plurality of digital devices to the communication device.
Handover device of the digital device comprising a. The method of claim 1,
The handover server comprises:
If the data processing capacity of the default digital device is exceeded by measuring the load of the default digital device connected to the communication device by default, the switch unit may be controlled to provide a resource capable of processing the excess data among the plurality of digital devices. Handover device of a digital device, characterized in that to connect said communication device with a replacement digital device. The method of claim 1,
The handover server comprises:
When the terminal device initially connected by the default digital device connected to the communication device transmits the connection request again in an idle state or an RRC-connected state, the load request of the default digital device may be measured to process the connection request. And when there is no connection, controlling the switch unit to connect the communication device with an alternative digital device having a resource capable of processing the excess data among the plurality of digital devices. The method of claim 3, wherein
The handover server comprises:
The switching device of the alternative digital device and the communication device, the handover device of the digital device, characterized in that for controlling the transmission of the management parameters of the terminal device from the default digital device to the alternative digital device. The method of claim 1,
The handover server comprises:
When a digital device to process the data is set in advance according to the type of data transmitted or received from the terminal device, after searching for the digital device corresponding to the type of data from the terminal device, the communication is performed by controlling the switch unit. And handing over the device to the retrieved digital device. The method of claim 1,
The handover server comprises:
Provides management parameter information of a terminal device connected to the communication device to one alternative digital device selected from the plurality of digital devices, and simultaneously with a default digital device connected to the communication device by default for data from the terminal device. Handover device of the digital device, characterized in that the control to process the data. The method of claim 1,
The digital device includes:
Connected to the communication device to perform signal processing to transmit the data to a core network of a mobile communication system, and transmits a signal received from the core network to the communication device. As a handover method for a digital device,
Receiving a connection request from a terminal device through a communication device of a base station;
Checking whether a data processing capacity of a default digital device that is connected to the communication device by default when the connection request is received is exceeded;
Searching for a replacement digital device capable of processing the excess data when the capacity of the default digital device is exceeded;
Connecting the substitute digital device to the communication device to process an access request of the terminal device;
Handover method of a digital device comprising a. As a handover method for a digital device,
Transmitting, by an arbitrary terminal device, a connection request again in an idle state or an RRC-connected state through a communication device of the base station;
When receiving the connection request, measuring a load state of a default digital device connected to the communication device by default;
Searching for an alternative digital device capable of processing the connection request if the default digital device cannot process the connection request as a result of the measurement;
Connecting the alternate digital device and the communication device to process the connection request;
Handover method of a digital device comprising a. The method of claim 9,
In processing the connection request,
The management parameter information for the terminal device is transmitted from the default digital device to the alternative digital device handover method. As a handover method for a digital device,
Receiving data transmitted or received from a terminal device through a communication device of the base station;
Analyzing the type of data and searching for a digital device configured to process the data;
Connecting the retrieved digital device and the communication device to process data of the terminal device;
Handover method of a digital device comprising a. As a handover method for a digital device of a base station,
Receiving data transmitted or received from a terminal device through a communication device of the base station;
Processing the data in a default digital device that is default connected to the communication device;
Providing management information of the terminal device to an alternative digital device replacing the default digital device;
Processing data of the terminal device together with the default digital device in the alternative digital device;
Handover method of a digital device comprising a.

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