JP2015177523A - Radio base station device, radio terminal device, cell type information acquisition method and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base station capable of automatically acquiring cell type information of a cell in another base station.SOLUTION: A terminal UE transmits cell type information which indicates a PCI of a neighboring cell and a cell type of the neighboring cell to a base station (Cell#1) as a measurement report (Step S11). The base station (Cell#1) records cell type information of Cell#2, Cell#3 and Cell#4 included in the measurement report from the terminal UE in the own NRT (Step S15). Thus, the cell type information 'cell-type#2', 'cell-type#3' and 'cell-type#4' of the neighboring cells Cell#2, Cell#3 and Cell#4 is stored in the NRT of the base station (Cell#1).

Description

  The present invention relates to a radio base station apparatus, a radio terminal apparatus, a cell type information acquisition method, and a computer program.

  In recent years, a wireless communication network called HetNet (Heterogeneous Network) is known. In HetNet, a plurality of cells having different cell sizes and the like are partially or entirely overlapped. In a wireless communication system (LTE system) called LTE (Long Term Evolution) that is being standardized by 3GPP (3rd Generation Partnership Project) (for example, see Non-Patent Documents 1 and 2), different types of HetNet The use of these cells for high-speed communication services and traffic load balancing (traffic offloading) is being considered.

  In the LTE system, the hand over parameter is scaled according to the cell type of the target cell (Target Cell) or the cell type of the serving cell and the target cell. Technology has been studied (for example, see Non-Patent Documents 3, 4, and 5). Further, a re-establishment target cell prepared for recovery from a radio link failure (RLF) has been studied (see, for example, Non-Patent Document 6).

3GPP, TS 36.300, “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2” 3GPP TS 32.511, “Telecommunication management; Automatic Neighbor Relation (ANR) management; Concepts and requirements” 3GPP TSG-RAN WG2 Meeting R2-133584, “UE based solutions for mobility robustness” 3GPP TSG RAN WG2 Meeting # 84 R2-134300, “Further study on HO parameters scaling based on cell type”, Intel Corporation 3GPP TSG RAN WG2 Meeting # 84 R2-134098, “Way forward for Hetnet mobility robustness enhancements”, NSN, Nokia 3GPP TSG RAN WG2 Meeting # 84 R2-133435, “Solutions to improve RLF recovery in HetNet deployment”, Huawei

  In order to use the cell type in the above-described handover parameter scaling, re-establishment target cell preparation, etc., the base station (E-UTRAN NodeB: eNB) has the type of cell (type ( It is desirable to acquire cell type information that is information indicating type)) and notify the terminal (user equipment: UE). However, the conventional base station cannot automatically acquire the cell type information of the cells of other base stations. For this reason, if the operation manager manually sets the cell type information of the cells of other base stations to the base station, it causes a cost increase.

  The present invention has been made in view of such circumstances, and a base station can automatically acquire cell type information of a cell of another base station, a radio base station apparatus, a radio terminal apparatus, It is an object to provide a cell type information acquisition method and a computer program.

(1) A radio base station apparatus according to the present invention receives a measurement report including cell type information of a cell of another radio base station apparatus from a radio terminal apparatus.
(2) The radio base station apparatus according to the present invention receives an information report including cell type information of a cell of another radio base station apparatus as a response to the information request to the radio terminal apparatus.
(3) A radio base station apparatus according to the present invention is characterized in that in the radio base station apparatus of either (1) or (2), the cell type information is received by an ANR function.
(4) The radio base station apparatus according to the present invention is characterized in that, in the radio base station apparatus of (3), the received cell type information is stored in a neighbor relation table.
(5) The radio base station apparatus according to the present invention creates a white list or black list relating to handover based on the cell type information in any of the radio base station apparatuses of (1) to (4) above. Features.

(6) The radio terminal apparatus according to the present invention transmits a measurement report including cell type information of a cell of a radio base station apparatus other than the radio base station apparatus to which the radio terminal apparatus is connected to the radio base station apparatus. To do.
(7) The radio terminal apparatus according to the present invention transmits an information report including cell type information of a cell of a radio base station apparatus other than the radio base station apparatus as a response to the information request from the radio base station apparatus. It is characterized by.

(8) The cell type information acquisition method according to the present invention includes a step in which the radio base station apparatus receives a measurement report including cell type information of a cell of another radio base station apparatus from the radio terminal apparatus. Features.
(9) The cell type information acquisition method according to the present invention includes a step in which a radio base station apparatus makes an information request to a radio terminal apparatus, and the radio base station apparatus responds to the information request from the radio terminal apparatus. Receiving an information report including cell type information of a cell of another radio base station apparatus as a response.

(10) The cell type information acquisition method according to the present invention executes a step of receiving, from a wireless terminal device, a measurement report including cell type information of a cell of another wireless base station device, to a computer of the wireless base station device. It is a computer program for making it happen.
(11) A cell type information acquisition method according to the present invention includes a step of making an information request to a wireless terminal device to a computer of a wireless base station device, and another wireless as a response to the information request from the wireless terminal device. And a step of receiving an information report including cell type information of a cell of the base station apparatus.

  According to the present invention, it is possible to obtain an effect that a base station can automatically acquire cell type information of a cell of another base station.

It is a conceptual diagram which shows the structural example of HetNet which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the terminal UE which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the base station eNB which concerns on one Embodiment of this invention. It is a graph which shows the structural example of NRT which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the ANR function part 231 which concerns on one Embodiment of this invention. It is a sequence chart which shows the procedure of the cell type information acquisition method which concerns on Example 1 of this invention. It is a sequence chart which shows the example of the process sequence of terminal UE and base station eNB_m (Cell # 1) which concerns on Example 1 of this invention. It is a sequence chart which shows the procedure of the cell type information acquisition method which concerns on Example 2 of this invention. It is a sequence chart which shows the example of the process sequence of terminal UE which concerns on Example 2 of this invention, and base station eNB_m (Cell # 1). It is a sequence chart which shows the procedure of the hand-over method which concerns on Example 3 of this invention. It is a sequence chart which shows the example of the process sequence of terminal UE and base station eNB_m (Cell # 1) which concerns on Example 3 of this invention. It is a chart which shows the structural example of the cell type information which concerns on one Embodiment of this invention. It is a chart which shows the structural example of the cell type information which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an LTE system will be described as an example of a wireless communication system.

  FIG. 1 is a conceptual diagram showing a configuration example of HetNet according to an embodiment of the present invention. In FIG. 1, macro cell base stations eNB_m1 and eNB_m2 provide macro cells C_m1 and C_m2, respectively. Small cell base stations eNB_s1, eNB_s2, eNB_s3, eNB_s4, eNB_s5, eNB_s6, eNB_s7 provide small cells C_s1, C_s2, C_s3, C_s4, C_s5, C_s6, and C_s7, respectively. The macro cells C_m1 and C_m2 have a wider coverage than the small cells C_s1, C_s2, C_s3, C_s4, C_s5, C_s6, and C_s7. The macro cells C_m1 and C_m2 are partially overlapped. The small cells C_s1, C_s2, C_s3, and C_s4 are overlapped with the macro cell C_m1. The small cells C_s4, C_s5, C_s6, and C_s7 are arranged overlapping the macro cell C_m2.

  Hereinafter, the macro cell base stations eNB_m1 and eNB_m2 are referred to as “macro cell base station eNB_m” when they are not particularly distinguished. In addition, the small cell base stations eNB_s1, eNB_s2, eNB_s3, eNB_s4, eNB_s5, eNB_s6, and eNB_s7 are referred to as “small cell base station eNB_s” when not particularly distinguished. Further, when the macro cell base station eNB_m and the small cell base station eNB_s are not particularly distinguished, they are referred to as “base station eNB”.

  The terminal UE can connect to both the macro cell base station eNB_m and the small cell base station eNB_s. While moving in the direction of the arrow in FIG. 1, the terminal UE can change the connection destination base station eNB by handover as appropriate.

  FIG. 2 is a block diagram illustrating a configuration example of a terminal (wireless terminal apparatus) UE according to an embodiment of the present invention. In FIG. 2, the terminal UE includes a radio communication unit 11, a control unit 12, a storage unit 13, an input unit 14, and an output unit 15. The wireless communication unit 11, the control unit 12, the storage unit 13, the input unit 14, and the output unit 15 are connected so that data can be transmitted and received between them. The radio communication unit 11 can wirelessly connect to the macro cell base station eNB_m and the small cell base station eNB_s. The wireless communication unit 11 communicates with other devices via the base station eNB that is wirelessly connected.

  The control unit 12 controls operations related to the terminal UE. The storage unit 13 stores data. The input unit 14 inputs data. The output unit 15 outputs data. Examples of the input unit 14 include an input device such as a keyboard, a numeric keypad, and a mouse, a microphone for inputting sound, and a receiving device for short-range wireless communication. Examples of the output unit 15 include a display device such as a liquid crystal display device, a speaker that outputs sound, and a transmission device for short-range wireless communication. Moreover, you may provide the touchscreen which has the function of both an input device and a display device. Examples of the terminal UE include a mobile communication terminal device such as a smartphone or a tablet computer (tablet PC).

  FIG. 3 is a block diagram illustrating a configuration example of a base station (radio base station apparatus) eNB according to an embodiment of the present invention. In FIG. 3, the base station eNB includes a radio communication unit 21, a communication unit 22, a control unit 23, and a storage unit 24. The wireless communication unit 21, the communication unit 22, the control unit 23, and the storage unit 24 are connected so that data can be transmitted and received between them. The radio communication unit 21 performs radio communication with the terminal UE. The communication unit 22 communicates with other devices via the backbone network. The control unit 23 controls operations related to the base station eNB. The storage unit 24 stores data.

  The control unit 23 includes an ANR (Automatic Neighbor Relation) function unit 231. The ANR function unit 231 performs processing for automatically acquiring a relationship with a cell near the own base station eNB. An ANR function (Automatic Neighbor Relation Function) in the LTE system is disclosed in Non-Patent Documents 1 and 2, for example.

  The storage unit 24 includes a neighbor relation table (NRT) 241. NRT_241 stores information indicating a relationship with a cell near the base station eNB. NRT in the LTE system is disclosed in Non-Patent Document 1, for example.

  FIG. 4 is a chart showing a configuration example of the NRT according to the present embodiment. In the present embodiment, cell type information that was not found in NRT in the conventional LTE system is added to NRT_241. In FIG. 4, NRT_241 includes a TCI (Target Cell Identifier), a deletion prohibition flag (No Remove), a handover prohibition flag (No HO), and an X2 no-line flag (No X2) for each neighbor relation (NR). Stores cell type information (Cell Type). In FIG. 4, a circle indicates that the corresponding flag is present.

  The TCI is composed of an “E-UTRAN Cell Global Identifier (ECGI)” and a “Physical cell identifier (PCI)”. The deletion prohibition flag indicates that deletion of the entry related to the neighborhood (information registered in NRT_241) is prohibited. The handover prohibition flag indicates prohibiting handover to the neighboring cell. The X2 line absence flag indicates that an X2 line is not established with the neighboring base station eNB. The X2 line is a line for connecting the base stations eNB in the LTE system. The cell type information indicates the cell type of the neighboring cell.

  In the example of FIG. 4, as the neighbor relationship information specified by the identifier “1”, the TCI “TCI # 1”, the deletion prohibition flag “none”, the handover prohibition flag “none”, the X2 no-line flag “none”, and the cell Type information “Type # 1” is stored in NRT_241. Further, as information on the neighbor relationship specified by the identifier “2”, the TCI “TCI # 2”, the deletion prohibition flag “present”, the handover prohibition flag “none”, the X2 no-line flag “present”, and the cell type information “Type” are used. # 2 "is stored in NRT_241. In addition, as information on the neighbor relationship specified by the identifier “3”, the TCI “TCI # 3”, the deletion prohibition flag “present”, the handover prohibition flag “none”, the X2 no-line flag “none”, and the cell type information “Type” are used. # 3 "is stored in NRT_241.

  FIG. 5 is a block diagram illustrating a configuration example of the ANR function unit 231 according to the present embodiment. In FIG. 5, the ANR function unit 231 includes an NRT management function unit 231a, a neighbor removal function unit 231b, and a neighbor detection function unit 231c.

  The NRT management function unit 231a manages NRT_241. The NRT management function unit 231a receives an instruction to add or update a neighborhood relationship from the operation / maintenance device (O & M) of the LTE system. The NRT management function unit 231a reports neighborhood relations to the operation / maintenance device (O & M). The NRT management function unit 231a receives an instruction to remove the neighborhood relationship from the neighborhood removal function unit 231b. The NRT management function unit 231a removes the entry of the corresponding neighbor relationship from the NRT_241 based on the neighbor relation removal instruction received from the neighbor removal function unit 231b. The NRT management function unit 231a receives an instruction to add a neighbor relationship from the neighbor detection function unit 231c. The NRT management function unit 231a adds an entry of the corresponding neighbor relationship to the NRT_241 based on the neighbor relationship addition instruction received from the neighbor detection function unit 231c.

  The neighborhood removal function unit 231b instructs the NRT management function unit 231a to remove the neighborhood relationship based on the neighborhood relationship information 2310 generated inside the base station eNB.

  The proximity detection function unit 231c receives a measurement report (MR) from the terminal UE from an RRC (Radio Resource Control) unit 232. The proximity detection function unit 231c requests the RRC unit 232 to perform measurement by the terminal UE. Based on the measurement report by the terminal UE received from the RRC unit 232, the proximity detection function unit 231c instructs the NRT management function unit 231a to add a neighbor relationship.

  The RRC unit 232 is configured as one functional unit of the control unit 23 in the base station eNB.

  Next, examples according to the present embodiment will be described.

  In Example 1, the base station eNB acquires the cell type information of the cells of other base stations eNB by the ANR function. FIG. 6 is a sequence chart illustrating the procedure of the cell type information acquisition method according to the first embodiment of the invention. In the example of FIG. 6, the terminal UE is connected to the macro cell base station eNB_m (hereinafter referred to as base station eNB_m (Cell # 1)) of the macro cell Cell # 1 (RRC connection state (RRC_CONNECTED)). A small cell Cell # 3 is arranged in the macrocell Cell # 1. Further, the macro cell Cell # 2 is arranged in the vicinity of the macro cell Cell # 1. A small cell Cell # 4 is arranged in the macrocell Cell # 2.

(Step S11) The terminal UE transmits, to the base station eNB_m (Cell # 1), cell type information indicating the PCI of the neighboring cell determined to have strong signal strength and the cell type of the neighboring cell as a measurement report. Send. In the example of FIG. 6, it is assumed that the neighboring cells are the macro cell Cell # 2 and the small cells Cell # 3, Cell # 4. In addition, cell type information may be acquired from the measurement result of a neighboring cell, or may be acquired from the base station eNB of a neighboring cell.

(Step S12) The base station eNB_m (Cell # 1) requests a GCI (global cell identifier) and other predetermined information related to a neighboring cell of the PCI included in the measurement report received from the terminal UE, from the terminal UE.

(Step S13) In response to a request from the base station eNB_m (Cell # 1), the terminal UE receives a BCCH (broadcasting channel) signal of each of the neighboring cells Cell # 2, Cell # 3, and Cell # 4. GCI and other predetermined information of each neighboring cell Cell # 2, Cell # 3, Cell # 4 are acquired from the BCCH reception signal of each neighboring cell Cell # 2, Cell # 3, Cell # 4.

(Step S14) The terminal UE transmits the GCI and other predetermined information of each of the neighboring cells Cell # 2, Cell # 3, and Cell # 4 to the base station eNB_m (Cell # 1).

(Step S15) The base station eNB_m (Cell # 1) records the cell type information of each neighboring cell Cell # 2, Cell # 3, Cell # 4 included in the measurement report from the terminal UE with respect to its own NRT_241. To do. Thereby, cell type information “cell-type # 2”, “cell-type # 3” of each neighboring cell Cell # 2, Cell # 3, Cell # 4 is transmitted to NRT_241 of the base station eNB_m (Cell # 1). “Cell-type # 4” is stored.

  Next, an example of operations of the terminal UE and the base station eNB according to the first embodiment will be described with reference to FIG. FIG. 7 is a sequence chart illustrating an example of a processing procedure of the terminal UE and the base station eNB_m (Cell # 1) according to the first embodiment of the present invention. The example of FIG. 7 corresponds to the cell arrangement example shown in FIG. The terminal UE is connected to the base station eNB_m (Cell # 1) (RRC_CONNECTED).

(Step S21) The ANR function unit 231 of the base station eNB_m (Cell # 1) requests the terminal UE to measure a neighboring cell using the radio communication unit 21.

(Step S22) In response to a request from the base station eNB_m (Cell # 1), the terminal UE measures a neighboring cell by the wireless communication unit 11. In the measurement of this neighboring cell, the base station eNB_m (Cell # 1) uses the same frequency band as the base station eNB cell (intra-frequency neighboring cell), and the base station eNB_m (Cell # 1) has a different frequency band. The cell (inter-frequency neighboring cell) of the base station eNB to be used is measured.

(Step S23) The terminal UE transmits the cell type information indicating the PCI of the neighboring cell and the cell type of the neighboring cell as a measurement report to the base station eNB_m (Cell # 1) by the radio communication unit 11. Here, it is assumed that the neighboring cells are the macro cell Cell # 2 and the small cells Cell # 3, Cell # 4. In addition, cell type information may be acquired from the measurement result of a neighboring cell, or may be acquired from the base station eNB of a neighboring cell.

  The ANR function unit 231 of the base station eNB_m (Cell # 1) receives the measurement report from the terminal UE by the radio communication unit 21. The neighbor cell measurement report includes a list of frequency bands used by each cell, a list of functions supported by each cell, and the like.

(Step S24) The ANR function unit 231 of the base station eNB_m (Cell # 1) performs GCI related to the neighboring cell of the PCI included in the measurement report received from the terminal UE by the wireless communication unit 21 and other information to the terminal UE. Request predetermined information. Examples of the other predetermined information include ECGI, TAC, “PLMN ID”, and the like.

(Step S25) In response to a request from the base station eNB_m (Cell # 1), the terminal UE receives the BCCH signals of the neighboring cells Cell # 2, Cell # 3, and Cell # 4 by the wireless communication unit 11. To do. The terminal UE acquires the GCI of each neighboring cell Cell # 2, Cell # 3, Cell # 4 and other predetermined information from the BCCH reception signal of each neighboring cell Cell # 2, Cell # 3, Cell # 4. And terminal UE transmits each GCI and other predetermined information of neighboring cell Cell # 2, Cell # 3, Cell # 4 by the radio | wireless communication part 11 with respect to base station eNB_m (Cell # 1).

(Step S26) The ANR function unit 231 of the base station eNB_m (Cell # 1) updates the NRT_241 of the own base station. In the update of this NRT_241, the cell type information of each neighboring cell Cell # 2, Cell # 3, Cell # 4 included in the measurement report from the terminal UE is recorded as corresponding neighboring relationship information.

  In addition, in Example 1 mentioned above, macrocell base station eNB_m acquired the cell type information of the neighboring cell by the ANR function. Similarly, the small cell base station eNB_s acquired the cell type information of the neighboring cell by the ANR function. Also good.

  In the first embodiment, the base station eNB can acquire the cell type information of the neighboring cell by the measurement report from the terminal UE in the ANR function.

  The second embodiment is another example in which the base station eNB acquires cell type information of cells of other base stations eNB by the ANR function as in the first embodiment. FIG. 8 is a sequence chart showing the procedure of the cell type information acquisition method according to the second embodiment of the present invention. The cell arrangement example of FIG. 8 is the same as that of FIG. The terminal UE is connected to the base station eNB_m (Cell # 1) (RRC_CONNECTED).

(Step S31) The terminal UE transmits, as a measurement report, the PCI of a neighboring cell determined to have strong signal strength to the base station eNB_m (Cell # 1). In the example of FIG. 8, it is assumed that the neighboring cells are the macro cell Cell # 2 and the small cells Cell # 3, Cell # 4.

(Step S32) The base station eNB_m (Cell # 1) requests the terminal UE for GCI, cell type information, and other predetermined information regarding the neighboring cells of the PCI included in the measurement report received from the terminal UE.

(Step S33) In response to a request from the base station eNB_m (Cell # 1), the terminal UE receives the BCCH signals of the neighboring cells Cell # 2, Cell # 3, and Cell # 4. GCI and other predetermined information of each neighboring cell Cell # 2, Cell # 3, Cell # 4 are acquired from the BCCH reception signal of each neighboring cell Cell # 2, Cell # 3, Cell # 4.

(Step S34) The terminal UE transmits the GCI, cell type information, and other predetermined information of the neighboring cells Cell # 2, Cell # 3, and Cell # 4 to the base station eNB_m (Cell # 1). In addition, cell type information may be acquired from the measurement result of a neighboring cell, or may be acquired from the base station eNB of a neighboring cell.

(Step S35) The base station eNB_m (Cell # 1) records the cell type information of each neighboring cell Cell # 2, Cell # 3, and Cell # 4 received from the terminal UE with respect to its own NRT_241. Thereby, cell type information “cell-type # 2”, “cell-type # 3” of each neighboring cell Cell # 2, Cell # 3, Cell # 4 is transmitted to NRT_241 of the base station eNB_m (Cell # 1). “Cell-type # 4” is stored.

  Next, an example of operations of the terminal UE and the base station eNB according to the second embodiment will be described with reference to FIG. FIG. 9 is a sequence chart illustrating an example of a processing procedure of the terminal UE and the base station eNB_m (Cell # 1) according to the second embodiment of the present invention. The example of FIG. 9 corresponds to the cell arrangement example shown in FIG. The terminal UE is connected to the base station eNB_m (Cell # 1) (RRC_CONNECTED).

(Step S41) The ANR function unit 231 of the base station eNB_m (Cell # 1) requests the terminal UE to measure a neighboring cell using the radio communication unit 21.

(Step S42) In response to a request from the base station eNB_m (Cell # 1), the terminal UE measures a neighboring cell by the wireless communication unit 11. In the measurement of this neighbor cell, the cell of the base station eNB that uses the same frequency band as the base station eNB_m (Cell # 1) and the cell of the base station eNB that uses a frequency band different from the base station eNB_m (Cell # 1) To be measured.

(Step S43) The terminal UE transmits the PCI of the neighboring cell as a measurement report by the radio communication unit 11 to the base station eNB_m (Cell # 1). Here, it is assumed that the neighboring cells are the macro cell Cell # 2 and the small cells Cell # 3, Cell # 4. The ANR function unit 231 of the base station eNB_m (Cell # 1) receives the measurement report from the terminal UE by the radio communication unit 21. The neighbor cell measurement report includes a list of frequency bands used by each cell, a list of functions supported by each cell, and the like.

(Step S44) The ANR function unit 231 of the base station eNB_m (Cell # 1) sends the GCI and cell type related to the neighboring cells of the PCI included in the measurement report received from the terminal UE by the radio communication unit 21 to the terminal UE. Request information and other predetermined information. Examples of the other predetermined information include ECGI, TAC, “PLMN ID”, and the like.

(Step S45) In response to a request from the base station eNB_m (Cell # 1), the terminal UE receives the BCCH signals of the neighboring cells Cell # 2, Cell # 3, and Cell # 4 by the wireless communication unit 11. To do. The terminal UE acquires the GCI of each neighboring cell Cell # 2, Cell # 3, Cell # 4 and other predetermined information from the BCCH reception signal of each neighboring cell Cell # 2, Cell # 3, Cell # 4. Then, the terminal UE uses the radio communication unit 11 to the base station eNB_m (Cell # 1), and each GCI, cell type information, and other predetermined information of the neighboring cells Cell # 2, Cell # 3, and Cell # 4 Send. In addition, cell type information may be acquired from the measurement result of a neighboring cell, or may be acquired from the base station eNB of a neighboring cell.

(Step S46) The ANR function unit 231 of the base station eNB_m (Cell # 1) updates the NRT_241 of the own base station. In the update of NRT_241, the cell type information of each neighboring cell Cell # 2, Cell # 3, Cell # 4 received from the terminal UE is recorded as the information on the corresponding neighboring relationship.

  In the second embodiment described above, the macro cell base station eNB_m acquires the cell type information of the neighboring cell by the ANR function. Similarly, the small cell base station eNB_s acquires the cell type information of the neighboring cell by the ANR function. Also good.

  In the second embodiment, the base station eNB can acquire the cell type information of the neighboring cell by the information report from the terminal UE in response to the information request of the neighboring cell to the terminal UE in the ANR function.

  In the third embodiment, cell type information is used for scaling of handover parameters. FIG. 10 is a sequence chart showing the procedure of the handover method according to the third embodiment of the present invention. In the example of FIG. 10, the terminal UE is connected to the macro cell base station eNB_m of the macro cell Cell # 1 (hereinafter referred to as base station eNB_m (Cell # 1)) (RRC_CONNECTED). A small cell Cell # 2 is arranged in the macrocell Cell # 1.

(Step S51) The base station eNB_m (Cell # 1) transmits, to the terminal UE, a white list or black list related to handover and cell type information of neighboring cells stored in the NRT_241. The white list regarding handover (hereinafter simply referred to as white list) is a list of target cell candidates for handover from the base station eNB_m (Cell # 1). However, the target cell candidate is selected based on the cell type information of the neighboring cell of the base station eNB_m (Cell # 1). The black list relating to handover (hereinafter simply referred to as black list) is a list of cells (hereinafter referred to as handover prohibited cells) that are prohibited from being used as target cells for handover from the base station eNB_m (Cell # 1). However, the handover prohibited cell is selected based on the cell type information of the neighboring cell of the base station eNB_m (Cell # 1).

(Step S52) The terminal UE selects a target cell based on the white list or black list received from the base station eNB_m (Cell # 1). Further, the terminal UE performs scaling of handover parameters based on the cell type information of neighboring cells. In this handover parameter scaling, the handover parameter is adjusted based on the cell type of the target cell or both the cell type of the target cell and the source cell.

(Step S53) The terminal UE measures the power of the signal of the small cell base station eNB_s of the small cell Cell # 2 that is the target cell, and uses the handover parameter determined in Step S52 to execute MR (for handover) Judgment of transmission of (Measurement Report).

(Step S54) If it determines with "transmit MR" by satisfy | filling MR transmission determination conditions by step S53, terminal UE will transmit MR with respect to base station eNB_m (Cell # 1).

(Step S55) The base station eNB_m (Cell # 1) that has received the MR from the terminal UE instructs the terminal UE to perform handover to the small cell Cell # 2 that is the target cell. And this terminal UE performs the hand-over to small cell Cell # 2.

  Next, an example of operations of the terminal UE and the base station eNB according to the third embodiment will be described with reference to FIG. FIG. 11: is a sequence chart which shows the example of the process sequence of terminal UE and base station eNB_m (Cell # 1) which concerns on Example 3 of this invention. The example of FIG. 11 corresponds to the cell arrangement example shown in FIG. The terminal UE is connected to the base station eNB_m (Cell # 1) (RRC_CONNECTED).

(Step S61) The control unit 23 of the base station eNB_m (Cell # 1) creates a white list or a black list based on the cell type information of neighboring cells stored in the NRT_241 of the own base station. Note that information other than the cell type information of neighboring cells may be used for creating the white list or the black list.

(Step S62) The control unit 23 of the base station eNB_m (Cell # 1) uses the white list or the black list and the cell type information of the neighboring cell stored in the NRT_241 to the terminal UE by the radio communication unit 21. Send.

(Step S63) Based on the white list or black list received from the base station eNB_m (Cell # 1) and the cell type information of the neighboring cell, the control unit 12 of the terminal UE selects the handover destination and the handover parameter. Perform scaling. In this handover parameter scaling, the handover parameter is adjusted based on the cell type of the target cell or the cell type of both the target cell and the source cell.

(Step S64) The control unit 12 of the terminal UE measures signal power for preparation for handover with respect to the small cell base station eNB_s of the small cell Cell # 2 that is the target cell. In preparation for this handover, the handover parameter scaled in step S63 is used.

(Step S65) The terminal UE performs a handover to the small cell Cell # 2, which is the target cell.

  According to the third embodiment, the cell type of the target cell, or the cell type of both the target cell and the source cell can be used for scaling of the handover parameter.

  Moreover, the base station eNB can create a white list or a black list based on cell type information of neighboring cells.

  Next, an example of cell type information according to the present embodiment will be described. Cell type information is defined as information related to a cell.

[Example 1: Cell type information based on cell coverage or base station transmission power]
Cell type information can be defined based on cell coverage or base station transmit power. FIG. 12 is a chart showing a configuration example of the cell type information. In the example of FIG. 12, a macro cell, a small cell, a pico cell, and a femto cell are defined as cell types. Each cell type is assigned a cell type identifier (cell type ID). In the example of FIG. 12, the cell type information can be composed of 2 bits for representing the cell type IDs “0”, “1”, “2”, and “3”.

[Example 2: Cell type information based on the role of the cell or the geographical location of the cell]
Cell type information can be defined based on the role of the cell or the geographical location of the cell. FIG. 13 is a chart showing a configuration example of the cell type information. In the example of FIG. 13, traffic offload and coverage complement are defined as cell types. As a cell for traffic offloading, for example, a cell arranged in the coverage of the cell can be cited. As a cell for coverage complementation, for example, a cell arranged near the edge of the cell can be cited. Each cell type is assigned a cell type ID. In the example of FIG. 13, the cell type information can be composed of 1 bit for representing the cell type IDs “0” and “1”.

[Example 3: Cell type information based on the location of the cell]
Cell type information can be defined based on the location of the cell. For example, a cell existing inside a building and a cell existing outside the building may be defined as different cell types and distinguished from each other.

[Example 4: Cell type information based on the height of the place where the cell is located relative to the cell inside the building]
Cell type information can be defined based on the height of the location of the cell relative to the cell inside the building. For example, for cells in the same building, a cell on a higher floor and a cell on a lower floor are defined as different cell types and distinguished from each other.

The example of cell type information mentioned above may be used independently, respectively, or may be used combining several. For example, combining the cell type information of Example 1 and Example 2 mentioned above is mentioned. As a specific example,
-Cell type information such as traffic offload and small cell traffic offload and picocell traffic offload and femtocell coverage supplement and small cell coverage complement and picocell coverage complement and femtocell.

According to the embodiment described above, the following effects can be obtained.
(1) The base station can automatically acquire cell type information of cells of other base stations.
(2) Based on the cell type information held by the base station, more information can be provided to improve the mobility of the terminal. Thereby, for example, handover in the RRC connection state (RRC_CONNECTED) can be performed smoothly. In addition, recovery from a radio link failure (RLF) in the RRC connection state can be performed smoothly.
(3) The base station can utilize the cell type information held by itself to reduce handover failures and radio link failures.
(4) The base station can create a white list or black list for handover based on cell type information of neighboring cells. Based on this white list and black list, for example, small cells can be used flexibly in HetNet.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  For example, the measurement report from the terminal UE may be performed autonomously by the terminal UE, or may be performed by the terminal UE by a measurement request from the base station eNB. The measurement report may be repeated.

  In the first and second embodiments described above, the base station eNB uses the ANR function to acquire cell type information from the terminal UE. However, a measurement report from the terminal UE and an information report for an information request to the terminal UE It is not limited to those included in the ANR function, but may be realized as a single function, or may be used as included in an arbitrary function.

  Further, the base station eNB may independently perform the acquisition of the cell type information by the measurement report from the terminal UE and the acquisition of the cell type information by the information report for the information request to the terminal UE, or You may implement combining both.

  For example, in the above-described embodiment, the LTE system is described as an example of the wireless communication system, but the present invention is also applicable to other wireless communication systems other than the LTE system.

Further, a computer program for realizing the functions of the terminal UE or the base station eNB described above is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into the computer system and executed. May be. Here, the “computer system” may include an OS and hardware such as peripheral devices.
“Computer-readable recording medium” refers to a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a DVD (Digital Versatile Disk), and a built-in computer system. A storage device such as a hard disk.

Further, the “computer-readable recording medium” means a volatile memory (for example, DRAM (Dynamic DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), etc., which hold programs for a certain period of time.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 11, 21 ... Wireless communication part, 12, 23 ... Control part, 13, 24 ... Memory | storage part, 14 ... Input part, 15 ... Output part, 22 ... Communication part, 231 ... ANR function part, 241 ... NRT, eNB ... Base Station (radio base station apparatus), UE ... terminal (radio terminal apparatus)

Claims (11)

  A radio base station apparatus that receives a measurement report including cell type information of a cell of another radio base station apparatus from a radio terminal apparatus.   A radio base station apparatus that receives an information report including cell type information of a cell of another radio base station apparatus as a response to an information request to a radio terminal apparatus.   The radio base station apparatus according to claim 1, wherein the cell type information is received by an ANR function.   The radio base station apparatus according to claim 3, wherein the received cell type information is stored in a neighbor relation table.   The radio base station apparatus according to any one of claims 1 to 4, wherein a white list or a black list relating to handover is created based on the cell type information.   A radio terminal apparatus that transmits a measurement report including cell type information of a cell of a radio base station apparatus other than the radio base station apparatus to which the radio terminal station is connected to the radio base station apparatus.   An information report including a cell type information of a cell of a radio base station apparatus other than the radio base station apparatus as a response to an information request from the radio base station apparatus. A radio base station apparatus receiving a measurement report including cell type information of a cell of another radio base station apparatus from a radio terminal apparatus;
A cell type information acquisition method comprising: The wireless base station device making an information request to the wireless terminal device;
The radio base station apparatus receives an information report including cell type information of a cell of another radio base station apparatus as a response to the information request from the radio terminal apparatus;
A cell type information acquisition method comprising: In the computer of the radio base station device,
Receiving a measurement report including cell type information of a cell of another radio base station device from the radio terminal device;
A computer program for running. In the computer of the radio base station device,
Making an information request to the wireless terminal device;
Receiving, from the wireless terminal device, an information report including cell type information of a cell of another wireless base station device as a response to the information request;
A computer program for running.

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