JP5924775B2 - Method and apparatus for setting correspondence between macro cell and small cell in HetNet - Google Patents

Description

  The present invention relates to a technique for setting a correspondence relationship between a macro cell and a small cell in HetNet.

  Mobile radio communication standardized by 3GPP such as 3G and LTE (for example, see Non-Patent Document 1) is widely used. In 3GPP, in order to expand the specifications of mobile radio communication, technical discussions targeting LTE-Advanced and the following are actively conducted. In the discussion of future mobile radio communication specifications in 3GPP, the concept of HetNet (Heterogeneous Network) is discussed regarding the configuration of base stations and cells serving as their service areas.

  HetNet develops a macro cell that covers a wide service area and provides a small cell (also called a pico cell) that covers a service area that is capable of high-speed communication but is narrower than the macro cell as needed. It is a communication method that is deployed in an overlapping manner in an area and provides a communication service to a mobile radio terminal (hereinafter simply “terminal”) through radio communication with the macro cell base station and / or the small cell base station. . In this method, by deploying small cells in spots in areas where communication is tight, it is possible to increase the traffic accommodated in those areas.

  As an extended concept of HetNet, a configuration called Phantom Cell has been proposed (see Non-Patent Document 2). In the Phantom Cell, the macro cell is in charge of C-Plane processing, and the small cell accommodates only U-Plane data communication.

  As a result, processing such as important communication and handover is processed on the macro cell side, and traffic such as Internet access can efficiently use small cell high-speed access by utilizing high-speed communication by small cells. It is.

  In the Phantom Cell, since the macro cell is in charge of the C-Plane, as shown in FIG. 1, the small cell adopts an architecture that is slaved to the macro cell. The macro cell and the small cell are connected via an IP network through an X2 interface defined by 3GPP as shown in FIG.

  At this time, it is necessary to set the correspondence (attribute) between the macro cell and the small cell, but the correspondence may change in order to cope with changes in the cell design, changes in the surrounding radio wave environment, macro cell failures, etc. There is. As shown in FIG. 3, considering the introduction of technology that dynamically changes the macrocell area (radius) by beamforming based on the concept of SON (Self Organized Network), it is necessary to cope with the change. It becomes. In the future, in order to accommodate increasing mobile radio communication traffic, the number of small cells may be as large as 1 million stations, and the correspondence between all macrocells and small cells must be manually created in the first place. Setting it may result in unrealistic operation. Thus, development of means for automatically setting the correspondence between the macro cell and the small cell has been demanded.

In the present invention, in order to achieve the object,
A macro cell that covers a wide service area is developed, and a small cell that can perform high-speed communication but covers a service area narrower than the macro cell is deployed in a superposed manner within the service area of the macro cell as necessary, and the macro cell A method of setting a correspondence relationship between a macro cell and a small cell in a communication system that provides a communication service to a terminal through wireless communication between the base station and / or the small cell base station,
A small cell base station scanning surrounding radio waves to detect the presence of a macro cell;
The base station of the small cell determines a macro cell to belong to among the detected macro cells;
The small cell base station is connected to the macro cell base station determined to belong to the small cell base station.

In the present invention, in order to achieve the object,
A macro cell that covers a wide service area is developed, and a small cell that can perform high-speed communication but covers a service area narrower than the macro cell is deployed in a superposed manner within the service area of the macro cell as necessary, and the macro cell A method of setting a correspondence relationship between a macro cell and a small cell in a communication system that provides a communication service to a terminal through wireless communication between the base station and / or the small cell base station,
A step in which each macro cell and small cell base station transmits information necessary for determining the correspondence between the macro cell and the small cell to the controller;
A controller determining a macro cell to which each small cell should belong based on the received information;
A controller transmitting a connection instruction according to the determination to a base station of each small cell;
The small cell base station that has received the connection instruction includes a step of connecting to the instructed macro cell base station.

  According to the present invention, a relationship between a macro cell and a small cell can be dynamically set in HetNet in response to a change in radio wave environment.

Explanatory drawing which shows an example of a HetNet structure Explanatory diagram of connection between base station of macro cell and base station of small cell Illustration of dynamic cell change of macro cell and change of correspondence of small cell by SON The block diagram which shows 1st Embodiment of the correspondence setting method of this invention The block diagram which shows 2nd Embodiment of the correspondence setting method of this invention

  In the present invention, the correspondence between the macro cell and the small cell is automatically set by the method described below.

  FIG. 4 shows a first embodiment of the correspondence setting method of the present invention, in which the base station of each small cell autonomously determines and determines the macro cell to which it belongs (connects). , 11 is a macro cell base station, and 12 is a small cell base station.

  In the above configuration, the base station 12 of each small cell scans the surrounding radio waves and detects the presence of the macro cell (1). When a plurality of macro cells are detected, the base station 12 of each small cell determines (selects) a macro cell to be attached (connected) according to a predetermined priority (2). Then, the small cell base station 12 transmits a connection request to the macro cell base station, which is determined to belong, here, the base station 11 (3), and establishes a connection (4).

  The priorities mentioned above are, for example, the priority order of the frequencies used in the macro cell, the order of the strength of the received radio waves from the macro cell (select a stronger macro cell), the cell unit, regardless of the macro cell and the small cell. The IDs (identifiers) set in the ID and are also included in the radio waves from the macro cell are described in the order of priority (simple ranking, ranking by time and day of the week) in advance. It shall be decided according to the list.

  Note that the base station 12 of each small cell performs the above-described ambient radio wave scanning (1) and attribution determination (2) at regular intervals. However, as a result of the determination, “the connection destination does not need to be changed”. If there is, the operations (3) and (4) are not performed.

  FIG. 5 shows a second embodiment of the correspondence setting method of the present invention, in this case using a dedicated controller for determining the belonging relationship, in which 21 is a controller and 22 is a macro cell base station. , 23 are small cell base stations.

  The controller 21 collects information necessary for determining the correspondence between the macro cell and the small cell, determines a macro cell to which each small cell should belong based on the information, and sends a connection instruction according to the determination to the base of each small cell. Send to the station.

  In the above configuration, the macro cell base station 22 and the small cell base station 23 upload (transmit) information necessary for determining the correspondence between the macro cell and the small cell to the controller 21 (1). The controller 21 determines the macro cell to which each small cell should belong based on the received information (2). In addition, the controller 21 transmits a connection instruction according to the determination to the base station 23 of each small cell (3). Upon receiving the connection instruction, the small cell base station 12 transmits a connection request to the corresponding macro cell base station, here, the base station 11 (4), and establishes a connection (5).

  Here, as information to be uploaded to the controller 21 from the base station 22 of each macro cell and the base station 23 of the small cell, information such as power intensity of received radio waves from surrounding cells, CID, transmission power, beamforming direction, There are geographical information such as latitude and longitude, traffic volume of the base station, and speed information of the backhaul line to which the base station is connected.

  Further, as the determination by the controller 21, for example, there is one in which a small cell belongs to a macro cell that is within the service area of the macro cell and is geographically closest. Moreover, a small cell with a large traffic amount may be associated with a macro cell with a higher backhaul line among the small cells in the service area of the macro cell.

  Note that the base station 23 of each small cell performs the above-described information upload (1) at regular intervals, but this “constant time” does not have to be the same for all the small cell base stations 23. In addition, the controller 21 also performs the above-described determination (2) of each small cell's attribution destination at regular time intervals. The “constant time” here and the “constant time” at the base station 23 of each small cell described above. Need not be identical. If the result of the determination in (2) is “no need to change the connection destination”, the controller 21 does not perform the operation in (3).

  11, 22: Macrocell base station, 12, 23: Small cell base station, 21: Controller.

3GPP TS 23.401 General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access (Release 11) NTT Docomo, "Requirements, Candidate Solutions & Technology Roadmap for LTE Rel-12 Onward," RWS-120010, 3GPP Workshop on Release 12 and onwards, Ljubljana, Slovenia, June 11-12, 2012.

Claims (4)

A macro cell that covers a wide service area is developed, and a small cell that can perform high-speed communication but covers a service area narrower than the macro cell is deployed in a superposed manner within the service area of the macro cell as necessary, and the macro cell A method of setting a correspondence relationship between a macro cell and a small cell in a communication system that provides a communication service to a terminal through wireless communication between the base station and / or the small cell base station,
A small cell base station scanning surrounding radio waves to detect the presence of a macro cell;
The base station of the small cell determines a macro cell to belong to among the detected macro cells;
And a step of connecting the small cell base station to the macro cell base station determined to belong to the small cell base station. A macro cell that covers a wide service area is developed, and a small cell that can perform high-speed communication but covers a service area narrower than the macro cell is deployed in a superposed manner within the service area of the macro cell as necessary, and the macro cell A method of setting a correspondence relationship between a macro cell and a small cell in a communication system that provides a communication service to a terminal through wireless communication between the base station and / or the small cell base station,
A step in which each macro cell and small cell base station transmits information necessary for determining the correspondence between the macro cell and the small cell to the controller;
A controller determining a macro cell to which each small cell should belong based on the received information;
A controller transmitting a connection instruction according to the determination to a base station of each small cell;
The small cell base station that has received the connection instruction includes a step of connecting to the instructed macro cell base station. A macro cell that covers a wide service area is developed, and a small cell that can perform high-speed communication but covers a service area narrower than the macro cell is deployed in a superposed manner within the service area of the macro cell as necessary, and the macro cell An apparatus for setting a correspondence relationship between a macro cell and a small cell in a communication system that provides a communication service to a terminal through wireless communication between the base station and / or the small cell base station,
It consists of a macro cell base station and a small cell base station,
The small cell base station scans surrounding radio waves, detects the presence of a macro cell, determines a macro cell to which the detected macro cell should belong, and bases of the macro cell that has been determined to belong A correspondence setting apparatus characterized by comprising at least means for connecting with a station. A macro cell that covers a wide service area is developed, and a small cell that can perform high-speed communication but covers a service area narrower than the macro cell is deployed in a superposed manner within the service area of the macro cell as necessary, and the macro cell An apparatus for setting a correspondence relationship between a macro cell and a small cell in a communication system that provides a communication service to a terminal through wireless communication between the base station and / or the small cell base station,
It consists of a controller, a macro cell base station, and a small cell base station,
The controller includes at least means for determining a macro cell to which each small cell should belong based on the received information, and means for transmitting a connection instruction according to the determination to a base station of each small cell,
The base station of the macro cell has at least means for transmitting information necessary for determining the correspondence between the macro cell and the small cell to the controller,
The small cell base station has at least means for transmitting information necessary for determining the correspondence between the macro cell and the small cell to the controller, and means for connecting to the instructed macro cell base station. Correspondence setting device.

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