JPWO2019159306A1 - User device and wireless communication method - Google Patents

Abstract

The UE200 performs measurements on neighboring cells and sends measurement reports to the radio access network. Specifically, the UE 200 uses the channel state information resource to measure interference from neighboring cells, and if the interference satisfies a predetermined condition, sends a measurement report to the radio access network.

Description

The present invention relates to a user device and a wireless communication method that performs measurement of neighboring cells and transmits a measurement report to a wireless access network.

The 3rd Generation Partnership Project (3GPP) has specified Long Term Evolution (LTE), and has specified LTE-Advanced (hereinafter referred to as LTE including LTE-Advanced) for the purpose of further speeding up LTE.

In LTE, the user equipment (UE) is the serving cell (cell of the connected state (RRC Connected) in the radio resource control (RRC) layer) and the reception quality of the neighboring cell formed in the vicinity of the serving cell (RSRP / RSRQ (Reference Signal)). A measurement report (Measurement Report) containing the measurement results of (Received Power / Reference Signal Received Quality), etc.) can be transmitted to the radio access network (E-UTRAN), specifically, the radio base station (eNB).

In addition, 3GPP is studying services and use cases using small unmanned aerial vehicles (UAVs) such as drones equipped with a wireless communication module similar to UE (see Non-Patent Document 1).

3GPP TR 36.777 V15.0.0 Section 7 Potential enhancements for supporting aerial vehicles, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on Enhanced LTE Support for Aerial Vehicles (Release 15), 3GPP, December 2017

Unlike ordinary UEs, UEs mounted on unmanned aerial vehicles (UAVs) fly over eNBs (cells), so they are not easily affected by obstacles such as buildings, and the propagation environment is easy to see. That is, such a UE is susceptible to interference from neighboring cells other than the serving cell.

When subjected to such interference, the UE may detect a radio link failure (RLF) before performing a measurement that triggers a handover to a neighboring cell because the reception quality of the serving cell deteriorates significantly. is there. Therefore, the UE may not be able to activate the handover or the like executed based on the measurement result of the neighboring cell, and may not be able to continue the communication.

Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a user device and a wireless communication method capable of more reliably performing measurement of a neighboring cell according to an interference state from a neighboring cell. And.

One aspect of the present invention is a user device (UE200) that executes measurement of neighboring cells (cells C2 and C3) and transmits a measurement report (Measurement Report) to a radio access network (radio access network 20). , The interference measurement unit (interference measurement unit 210) that measures interference from the neighboring cells using the channel state information resource (CSI-IM resource), and when the interference satisfies a predetermined condition, the measurement report is transmitted. It is provided with a measurement report transmission unit (measurement report transmission unit 220).

One aspect of the present invention is a wireless communication method in a wireless communication system (wireless communication system 10) that performs measurement of neighboring cells and transmits a measurement report to a wireless access network, using channel state information resources. A step of measuring the interference from the neighboring cells and a step of transmitting the measurement report when the interference satisfies a predetermined condition are included.

FIG. 1 is an overall schematic configuration diagram of the wireless communication system 10. FIG. 2 is a functional block configuration diagram of the UE 200. FIG. 3 is a diagram showing a communication sequence relating to transmission of a measurement report between the eNB 101 and the UE 200. FIG. 4 is a diagram showing a transmission operation flow of the measurement report by the UE 200. FIG. 5 is a diagram showing a specified example of Event C3. FIG. 6 is a diagram showing an example of ReportConfig EUTRA. FIG. 7 is a diagram showing an example of MeasObjectEUTRA. FIG. 8 is a diagram showing an example of Measure Results included in the Measurement Report. FIG. 9 is a diagram showing an example of the hardware configuration of the UE 200.

Hereinafter, embodiments will be described with reference to the drawings. The same functions and configurations are designated by the same or similar reference numerals, and the description thereof will be omitted as appropriate.

(1) Overall Schematic Configuration of Wireless Communication System FIG. 1 is an overall schematic configuration diagram of the wireless communication system 10 according to the present embodiment. The wireless communication system 10 is a wireless communication system according to Long Term Evolution (LTE), and includes a radio access network 20, a mobile station 150 (hereinafter, UE150), and a mobile station 200 (hereinafter, UE200).

The radio access network 20 is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) defined in 3GPP, and includes a radio base station 101 (hereinafter, eNB 101) to a radio base station 104 (hereinafter, eNB 104). The wireless communication system 10 is not necessarily limited to LTE (E-UTRAN). For example, the radio access network 20 may be a radio access network including a radio base station that executes wireless communication with a UE 200 (user device) defined as 5G.

The eNB101 to eNB104, UE150, and UE200 execute wireless communication according to the LTE specifications. In particular, in the present embodiment, the eNB 101 to eNB 104 form cells C1 to C4, respectively. UE150 is a normal UE such as a smartphone. On the other hand, the UE200 will be installed in small unmanned aerial vehicles (UAVs) such as the Drone 50.

Here, it is assumed that UE150 and UE200 use cell C1 as a serving cell. That is, cell C2 and cell C3 (neighboring cells) are formed in the vicinity of cell C1, which is a serving cell. The serving cell may be called PCell or PSCell (in the case of Dual Connectivity). Cell C4 (distant cell) is formed farther than cell C2 and cell C3.

The UE 150 and UE 200 can perform measurements on neighboring cells and send a measurement report to the radio access network 20. Specifically, UE150 and UE200 transmit a Measurement Report including the reception quality (RSRP / RSRQ, etc.) of the serving cell and neighboring cells to the radio access network 20.

Since the UE200 mounted on the drone 50 flies over eNB101 to eNB104, it is not easily affected by obstacles such as buildings, and the propagation environment is easy to see. Therefore, the UE 200 is susceptible to interference from neighboring cells (and distant cells) other than the serving cell (cell C1) (see the dotted line from the neighboring cell in the figure).

(2) Functional block configuration of the wireless communication system Next, the functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configuration of UE200 will be described.

FIG. 2 is a functional block configuration diagram of the UE 200. As shown in FIG. 2, the UE 200 includes an interference measurement unit 210 and a measurement report transmission unit 220.

The interference measuring unit 210 measures the interference from neighboring cells (cell C2 and cell C3). The interference measuring unit 210 may measure the interference in the distant cell (cell C4) when the visibility is good.

Specifically, the interference measurement unit 210 measures the interference received from neighboring cells by using the channel state information resource. In this embodiment, the channel state information resource means a channel state information (CSI) resource. CSI resources are specified in TS36.331, and CSI-RS (Reference Signal) and CSI-IM (Interference Measurement) are provided.

The interference measurement unit 210 measures interference from neighboring cells by using a channel state information resource for interference measurement, specifically, a CSI-IM resource.

The measurement report transmission unit 220 transmits a measurement report including the measurement results of the serving cell and neighboring cells to the radio access network 20. Specifically, the measurement report transmission unit 220 transmits a measurement report including the reception quality (RSRP / RSRQ, etc.) of the serving cell and neighboring cells to the radio access network 20.

The measurement report transmission unit 220 transmits a measurement report when interference from neighboring cells satisfies a predetermined condition. Specifically, the measurement report transmission unit 220 transmits a measurement report when the interference becomes larger than a predetermined threshold value.

That is, when the interference level (interference power) measured by the interference measurement unit 210 using the CSI-IM resource exceeds a predetermined threshold value, the measurement report transmission unit 220 outputs a measurement report indicating the measurement result of the neighboring cell. Send.

Such "when the interference becomes larger than the predetermined threshold", that is, "when the interference level (interference power) measured using the CSI-IM resource becomes equal to or higher than the predetermined threshold" is the Measurement Report. It is defined as a new event (referred to here as Event C3) that triggers the transmission of.

FIG. 5 shows a specified example of Event C3. Event C3 may be newly specified, for example, in Chapter 5.5.4 of TS36.331. As shown in FIG. 5, Event C3 defines a case where the interference level (interference power) measured using the CSI-IM resource becomes larger than a predetermined threshold value.

In Event C3, like other existing events (for example, Event C1), enterting conditions and leaving conditions are specified. The entertaining condition specifies whether or not the reception quality of the cell is included in the report target of the Measurement Report. The leaving condition specifies whether or not the reception quality of the cell is excluded from the report target of the Measurement Report.

The operation of transmitting the Measurement Report using Event C3 will be described later.

(3) Operation of Wireless Communication System Next, the operation of the wireless communication system 10 will be described. Specifically, the operation of transmitting the measurement report by the UE 200 will be described. As described above, in the present embodiment, the UE 200 is mounted on the drone 50, and the propagation environment can be easily seen.

FIG. 3 shows a communication sequence for transmitting a measurement report between the eNB 101 and the UE 200. Further, FIG. 4 shows a transmission operation flow of the measurement report by the UE 200.

Here, it is assumed that the UE 200 uses the cell C1 formed by the eNB 101 as a serving cell. As shown in FIG. 3, the UE 200 receives ReportConfigEUTRA (S10). ReportConfigEUTRA is included in RRC Connection Reconfiguration and so on.

FIG. 6 shows an example of ReportConfigEUTRA. In addition, FIG. 7 shows an example of MeasObjectEUTRA.

As shown in FIG. 6, ReportConfigEUTRA includes a threshold value (see underlined portion) related to Event C3 shown in FIG. Further, as shown in FIG. 7, MeasObjectEUTRA includes setting information (see underlined portion) regarding CSI-IM. MeasObjectEUTRA defines the measurement object of the Measurement Report applied to the E-UTRA cell, and is notified in advance from the radio access network 20 to the UE 200. The information elements (IE) of ReportConfigEUTRA and MeasObjectEUTRA are specified in TS36.331.

The UE200 measures the reception status based on the contents of the received ReportConfigEUTRA (S20). Specifically, the UE 200 uses CSI-IM resources to measure interference from neighboring cells (cells C2 and C3).

More specifically, the UE 200 measures interference from the Carrier Frequency to which the CSI-IM resource applies. Further, when the CSI-IM resource is set for each of a plurality of cells corresponding to the corresponding Carrier Frequency, the UE 200 measures the interference from each cell at the corresponding Carrier Frequency.

The UE 200 sends a measurement report of a neighboring cell to the radio access network 20, specifically the eNB 101, when the predetermined conditions specified by Event C3 are met (S30).

FIG. 8 shows an example of Measure Results included in the Measurement Report. As shown in FIG. 8, MeasureResults can include information about interference measured using CSI-IM resources (interference power, etc.) (see underlined part).

Next, the transmission operation flow of the measurement report by the UE 200 will be described. As shown in FIG. 4, the UE 200 uses the CSI-IM resource to measure interference from neighboring cells (cells C2 and C3) (S110).

The UE 200 also performs a measurement of the neighboring cell (S120). Specifically, the UE 200 measures the reception quality (RSRP / RSRQ, etc.) of neighboring cells. The operation of S120 may be executed in parallel with the operation of S110, or may be executed immediately before the operation of S140 described later. In other words, S110 and S120 are operations that are not performed after S140. The operation of S110 and S120 corresponds to S20 in FIG.

The UE 200 then determines whether the measured interference level (interference power) satisfies the condition specified by Event C3 (S130). Specifically, the UE 200 determines whether or not the interference level (interference power) measured using the CSI-IM resource becomes larger than a predetermined threshold value.

If the conditions specified by Event C3 are met, the UE 200 sends a measurement report to the radio access network 20 (specifically, eNB101) (S140). The operation of S140 corresponds to S30 in FIG. As mentioned above, the measurement report can include information about interference measured using CSI-IM resources (such as interference power).

(4) Action / Effect According to the above-described embodiment, the following action / effect can be obtained. The UE200 uses the channel state information resource (CSI-IM resource) to measure interference from neighboring cells. Therefore, the interference situation in the UE 200 mounted on the drone 50 can be detected quickly and surely. That is, according to the UE 200, the measurement of the neighboring cell can be performed more reliably according to the interference state from the neighboring cell.

In addition, the UE 200 transmits a Measurement Report when the measured interference satisfies a predetermined condition. Therefore, even when the UE 200 is interfered with by a neighboring cell, the radio access network 20 can realize the control to reduce the interference based on the Measurement Report received from the UE 200.

Examples of the control include control of transmission power of eNB and UE, and eICIC (enhanced Inter-Cell Interference Coordination). In addition, based on the Measurement Report, it is possible to realize the handover of the UE 200 to an appropriate cell that can reduce the interference.

In the present embodiment, the UE 200 transmits a Measurement Report when the interference becomes larger than a predetermined threshold value (when the enterting condition of Event C3 is satisfied). Therefore, the radio access network 20 can recognize the amount of interference received from the cell or the Carrier Frequency. For cells with a lot of interference or Carrier Frequency, by performing network coordination (eNB that forms a serving cell and eNB that forms a neighboring cell), the cell that is the source of interference can be stopped, or interference control can be performed by the method using eICIC. Can be realized.

In this embodiment, the UE 200 uses the CSI-IM resource to measure interference from neighboring cells. Therefore, it is possible to reliably measure the interference from neighboring cells while utilizing the existing CSI resource.

In this embodiment, as described above, the UE 200 is mounted on the drone 50. Therefore, even in the case of UE200, which is susceptible to interference from neighboring cells (and distant cells), the interference can be reduced quickly and reliably.

(5) Other Embodiments Although the contents of the present invention have been described above according to the embodiments, the present invention is not limited to these descriptions, and various modifications and improvements are possible. It is self-evident to the trader.

For example, in the above-described embodiment, the UE 200 is mounted on the drone 50 (UAV), but it does not necessarily have to be a drone as long as it is an object flying over eNB 101 to eNB 104 (about 300 m from the ground). Further, the flying object may be manned.

In the above-described embodiment, the operation when the UE 200 flies over the sky is disclosed, but whether or not the UE 200 is a user device flying over the sky is determined by (i) IMEISV (International Mobile Equipment Identity Software) of the user device. The above-described embodiment is also conceivable in which identification is performed by various methods such as (Version) or identification using contract type information, (ii) identification by separation of the connection destination APN (Access Point Name), and the identification is taken into consideration. Thereby, the present invention can realize a more flexible configuration and more efficient operation.

In the above-described embodiment, the interference from neighboring cells is measured using the CSI-IM resource, but the channel state information resource (CSI resource) does not necessarily have to be the CSI-IM resource. If available, CSI-RS resources may be used together or new CSI resources may be specified.

In the above-described embodiment, the UE 200 transmits a Measurement Report when the interference from neighboring cells becomes larger than a predetermined threshold value, but transmits a Measurement Report when the interference becomes worse than a predetermined threshold value. You may not do it.

Further, the block configuration diagram (FIG. 2) used in the description of the above-described embodiment shows a functional block. These functional blocks (components) are realized by any combination of hardware and / or software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one physically and / or logically coupled device, or directly and / or indirectly by two or more physically and / or logically separated devices. (For example, wired and / or wireless) may be connected and realized by these plurality of devices.

Further, the UE 200 described above may function as a computer for performing the processing of the present invention. FIG. 9 is a diagram showing an example of the hardware configuration of the UE 200. As shown in FIG. 9, the device may be configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

Each functional block of UE200 (see FIG. 2) is realized by any hardware element of the computer device or a combination of the hardware elements.

Processor 1001 operates, for example, an operating system to control the entire computer. The processor 1001 may be composed of a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, registers, and the like.

The memory 1002 is a computer-readable recording medium, and is composed of at least one such as ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and RAM (Random Access Memory). May be done. The memory 1002 may be called a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, or the like that can execute the method according to the above-described embodiment.

The storage 1003 is a computer-readable recording medium, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, an optical magnetic disk (for example, a compact disk, a digital versatile disk, or a Blu-ray). It may consist of at least one (registered trademark) disk), smart card, flash memory (eg, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, and the like. Storage 1003 may be referred to as auxiliary storage. The recording medium described above may be, for example, a database, server or other suitable medium containing memory 1002 and / or storage 1003.

The communication device 1004 is hardware (transmission / reception device) for communicating between computers via a wired and / or wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, or the like.

The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives an input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

Further, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. Bus 1007 may be composed of a single bus or different buses between devices.

Further, the notification of information is not limited to the above-described embodiment, and may be performed by other methods. For example, information notification includes physical layer signaling (eg DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (eg RRC signaling, MAC (Medium Access Control) signaling, broadcast information (MIB (MIB)). It may be implemented by Master Information Block), SIB (System Information Block)), other signals or a combination thereof. RRC signaling may also be referred to as an RRC message, eg, an RRC Connection Setup message, an RRC. It may be a Connection Reconfiguration message or the like.

Further, the input / output information may be stored in a specific location (for example, a memory) or may be managed by a management table. The input / output information can be overwritten, updated, or added. The output information may be deleted. The input information may be transmitted to another device.

The order of the sequences, flowcharts, and the like in the above-described embodiments may be changed as long as there is no contradiction.

Further, in the above-described embodiment, the specific operation performed by the eNB 101 to eNB 104 may be performed by another network node (device). Further, the function of the eNB may be provided by a combination of a plurality of other network nodes.

The terms described herein and / or the terms necessary for understanding the present specification may be replaced with terms having the same or similar meanings. For example, the channel and / or symbol may be a signal, where applicable. Also, the signal may be a message. Also, the terms "system" and "network" may be used interchangeably.

Further, the parameter or the like may be represented by an absolute value, a relative value from a predetermined value, or another corresponding information. For example, the radio resource may be indexed.

The eNB 101 to eNB 104 (base stations) can accommodate one or more (for example, three) cells (also referred to as sectors). When a base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, each smaller area being a base station subsystem (eg, small indoor base station RRH: Remote). Communication services can also be provided by Radio Head).

The term "cell" or "sector" refers to a part or all of the coverage area of a base station and / or base station subsystem that provides communication services in this coverage. In addition, the terms "base station," "eNB," "cell," and "sector" may be used interchangeably herein. Base stations are sometimes referred to by terms such as fixed station, NodeB, eNodeB (eNB), gNodeB (gNB), access point, femtocell, and small cell.

UE200 is a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, depending on the trader. , Remote terminal, handset, user agent, mobile client, client, or some other suitable term.

As used herein, the phrase "based on" does not mean "based on" unless otherwise stated. In other words, the statement "based on" means both "based only" and "at least based on".

Also, the terms "including," "comprising," and variants thereof are intended to be as comprehensive as "comprising." Furthermore, the term "or" as used herein or in the claims is intended not to be an exclusive OR.

Any reference to elements using designations such as "first", "second" as used herein does not generally limit the quantity or order of those elements. These designations can be used herein as a convenient way to distinguish between two or more elements. Thus, references to the first and second elements do not mean that only two elements can be adopted there, or that the first element must somehow precede the second element.

Throughout the specification, if articles are added by translation, for example, a, an, and the in English, these articles must not be clearly indicated by the context to be otherwise. , Shall include more than one.

Although embodiments of the present invention have been described above, the statements and drawings that form part of this disclosure should not be understood to limit the invention. Various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art from this disclosure.

As described above, according to the present invention, it is useful because the measurement of the neighboring cell can be performed more reliably according to the interference state from the neighboring cell.

10 Wireless communication system
20 Radio Access Network
50 drone
101-104 eNB
150, 200 UE
210 Interference measuring unit
220 Measurement report transmitter
1001 processor
1002 memory
1003 storage
1004 communication device
1005 input device
1006 output device
1007 bus

Claims (5)

A user device that performs measurements on neighboring cells and sends measurement reports to the radio access network.
An interference measuring unit that measures interference from the neighboring cells using the channel state information resource,
A user device including a measurement report transmission unit that transmits the measurement report when the interference satisfies a predetermined condition. The user device according to claim 1, wherein the measurement report transmitting unit transmits the measurement report when the interference becomes larger than a predetermined threshold value. The user device according to claim 1, wherein the interference measuring unit measures the interference using the channel state information resource for interference measurement. The user device according to claim 1, wherein the user device is mounted on an unmanned aerial vehicle including a drone. In a wireless communication system, it is a wireless communication method that performs measurement of neighboring cells and sends a measurement report to a wireless access network.
The step of measuring the interference from the neighboring cell using the channel state information resource, and
A wireless communication method including the step of transmitting the measurement report when the interference satisfies a predetermined condition.

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