KR20160094337A - Method and apparatus for measuring radio resource management - Google Patents

Abstract

Provided is a method of measuring radio resource management (RRM) by a terminal. The terminal receives one among reference signals (CSI-RS) for the measurement of channel state information (CSI) and discovery signals (DS), as RRF reference signals. Meanwhile, the terminal, by using the RRM-RS, measures the RRM reflecting the beam formation gain, while reporting the results of RRM to a serving base station. According to an embodiment, the terminal additionally measures RSRP and RSRQ where the RRM-RS based beam formation gain is included, thereby capable of accessing a cell which can improve the signal to noise plus interference (SINR) of a data channel or a control channel. Therefore, the performance of the system can be improved.

Description

[0001] METHOD AND APPARATUS FOR MEASURING RADIO RESOURCE MANAGEMENT [0002]

The present invention relates to a method and apparatus for the measurement of radio resource management.

(Or eNodeB) or a repeater (or an eNodeB) receiving a service in a mobile communication system (e.g., a system supporting a standard of a long term evolution (3GPP) Or radio resource management (RRM) in order to select (or reselect) a relay node or a handover to the base station. The base station or eNB described below may be replaced with a repeater or relay node.

The base station provides the relevant settings for the RRM measurement of the terminal, and the terminal accordingly performs the RRM measurement and reports the measurement to the base station periodically or event-triggered.

The RRM measurement object may include a reference signal received power (RSRP) or a reference signal received quality (RSRQ).

In 3GPP LTE, RSRP and RSRQ are defined based on a cell-specific reference signal (CRS) as an object of RRM measurement. The CRS is used for channel estimation to decode a control channel or a data channel. Therefore, the connection of the radio resource control (RRC) with the base station can be maintained only when the reception power or the reception quality of the CRS measured by the terminal satisfies a certain level. Here, a certain level of the received power or the reception quality may be at a level satisfying at least the required reception success rate of the control channel, where the control channel reception success rate may be, for example, 2% or more.

Meanwhile, when beamforming using multiple antennas or multiple input multiple output (MIMO) transmission is supported, RRM measurement and reporting methods are needed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for measuring and reporting RRM when beamforming using multiple antennas or MIMO transmission is supported.

According to an embodiment of the present invention, a method for measuring radio resource management (RRM) is provided. The RRM measurement method includes receiving at least one of a CSI-RS (reference signal) for channel state information (CSI) measurement and a discovery signal (DS) for a small cell search as an RRM-RS; Measuring an RRM reflecting a beamforming gain using the RRM-RS; And reporting to the serving base station the result of the RRM measurement reflecting the beamforming gain.

According to the embodiment of the present invention, it is possible to guarantee the required reception success rate of the control channel through the CRS-based RSRP and RSRQ measurement.

Also, according to an exemplary embodiment of the present invention, the UE may further improve signal-to-noise plus interference (SINR) of a data channel or a control channel by additionally measuring RSRP and RSRQ including a RRM-RS based beam- Can be connected to a cell that can be connected. This can improve system performance.

FIG. 1 is a diagram illustrating a method of performing RRM measurement and reporting including beam forming gain using an RRM-RS according to an embodiment of the present invention. Referring to FIG.
FIG. 2 is a diagram illustrating a method of performing RRM measurement and reporting including a beamforming gain according to another exemplary embodiment of the present invention. Referring to FIG.
3 is a diagram illustrating a base station according to an embodiment of the present invention.
4 is a diagram illustrating a terminal according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, a terminal may be referred to as a mobile terminal, a mobile station, an advanced mobile station, a high reliability mobile station, a subscriber station, A mobile subscriber station, a mobile subscriber station, an access terminal, a user equipment, and the like, and may also be referred to as a terminal, a mobile terminal, a mobile station, an advanced mobile station, An access terminal, a user equipment, and the like.

In addition, a base station (BS) includes an advanced base station, a high reliability base station, a node B, an evolved node B (eNodeB) an access point, a radio access station, a base transceiver station, a mobile multihop relay (MMR) -BS, a relay station serving as a base station, a high reliability repeater BS, Node B, eNodeB, access point, radio access station, transmitting / receiving base station, MMR-BS, and so on, may be referred to as a high reliability relay station, a repeater, A repeater, a high reliability repeater, a repeater, a macro base station, a small base station, and the like.

In the present specification, 'A or B' may include 'A', 'B', or 'both A and B'.

One. ' Beam forming  Including gain RRM  Reference signal for measurement '( RS : reference  How to send and set up a signal

When a base station supports multi-antenna transmission, a beam is formed in a specific direction according to the directivity of an antenna element or a weighted-sum for a plurality of antenna components so that a signal or a channel propagates .

Since the CRS is used for control channel decoding, the CRS is virtualized into a plurality of antenna components, including a single CRS antenna port (AP), to ensure cell coverage and wide beam width. Virtualization refers to a connection in which a magnitude and / or phase weight is applied between an input component and an output component.

There is a TXRU (transceiver unit) between the AP and the antenna component, and virtualization between the AP and the TXRU includes virtualization between the AP and the TXRU and virtualization between the TXRU and the antenna component.

The base station may include an enhanced control channel (hereinafter referred to as an " advanced-control channel ") that enables channel estimation based on a UE-specific RS to support data channel transmission over the number of CRS antenna ports, To support transmission of channel status information, to support coordinated multi-point (CoMP) transmission and reception, or for other purposes, to support the transmission of channel status information (CSI : CSI-RS for channel state information measurement.

Unlike the control channel, the base station transmits the data channel in a user equipment-specific manner. In a case where the BS supports multiple antennas, the BS receives inter-cell interference (inter-cell interference (ICI) and inter-layer interference (ILI) while receiving a data channel with a high signal- ), Or to mitigate inter-user interference (" IUI "), the data channel is transmitted via the beam having a narrow beam width.

The greater the number of antenna ports used for beamforming, the better the SINR of the target terminal, or the reduction of interference between cells, between layers, or between users. Therefore, measuring and reporting the CSI using a large number of CSI-RS antenna ports, and beam forming using the CSI can be advantageous for improving the beam forming gain as described above. As a result, cell (re-) selection and handover based on CRS-based RSRP and RSRQ measurements may not be optimal from a data reception point of view. That is, even if the RSRP and RSRQ levels based on the CRS are low, when the beam forming gain in the data channel is large, system performance may be deteriorated due to the RRM measurement in which the beam forming gain is not reflected.

For example, if cell A and cell B are adjacent or their cell coverage is overlapping, and the antenna array size of cell A is larger and the number of TXRUs is larger than cell B, the CRS-based RSRP for cell A and The SINR of the data channel (or an enhanced control channel) for the cell B may be higher than that of the cell A, even though the RSRQ is larger than the cell B, since the cell B has a high beam forming gain. If the RSRP and the RSRQ based on the CRS for the cell B are at a level that can satisfy the required reception success rate of the control channel, it is advantageous from the viewpoint of the system performance that the UE connects to the cell B rather than the cell A.

Hereinafter, a method of performing RRM measurement in consideration of beam forming gain in order to improve system performance will be described. Here, in the RRM measurement, the beam forming gain may be directly reflected or indirectly reflected. For example, in the RRM measurement, the beam width of the CSI-RS used in the CSI measurement for beamforming may be reflected. Hereinafter, for convenience of explanation, RRM measurement in which the beam forming gain is directly or indirectly considered or included is referred to as 'RRM measurement including beam forming gain' or 'RRM measurement including beam forming gain'.

In general, a MIMO channel can be represented by a matrix having a number of rows corresponding to the number of reception antennas of the UE and a number of columns corresponding to the number of transmission antennas of the BS. and the i-th row and the j-th column are channels between the i-th receive antenna and the j-th transmit antenna.

On the other hand, the base station may have two virtualization processes between an antenna element constituting a transmission antenna array or an antenna port AP for transmitting a signal or a physical channel with a radiation element. Here, the antenna port (AP) is a logical multiple input unit of the baseband.

Each antenna port passes through a virtualization block of the digital stage for mapping by a linear combination to TXRUs. And, the TXRU output thus virtualized with TXRU passes through the virtualization block of the analog stage, for mapping by linear combination to the antenna component or radiation component. Here, the mapping by linear combination means that each output value is obtained by adding a phase or size weight to a plurality of input values and summing them. For each output value, different weight values may be applied. In this way, each antenna port is virtualized with each antenna component or radiation component and transmitted to the terminal. Through virtualization, each antenna port can form a beam in a specific direction.

According to the virtualization method, it is possible to form the beams of all the antenna ports in the same direction, to form all the beams of all the antenna ports in different directions, or to form the same beam only between some antenna ports.

Beamforming or precoding is performed in consideration of an effective MIMO channel in which the antenna port of the base station is input and the reception antenna of the terminal is output in the baseband. If different virtualizations are applied, the radio channels are the same, but the MIMO channels in the baseband may have different values.

The above-mentioned virtualization method may include the following two methods.

Fully-connected virtualization (hereinafter referred to as 'first virtualization method') is a virtualization method of connecting an antenna port or TXRU to all antenna components. Virtualization can be performed such that the direction of the beam formed by each antenna port is different.

Subarray-partitioned virtualization (hereinafter, referred to as 'second virtualization method') is a method of dividing an antenna array into a plurality of subarrays and connecting antenna components belonging to each subarray to each antenna port (or TXRU). Virtualization can be performed so that the directions of the beams formed by each antenna port belonging to the same sub-array are the same.

For both the first and second virtualization methods, virtualization may be performed such that the direction of the beam formed by each antenna port is different and virtualization is performed such that the direction of the beam formed by each antenna port is the same It is possible.

On the other hand, for RRM measurement including beam forming gain in addition to CRS-based RRM measurement (including RSRP or RSRQ measurement based on CRS), it is necessary to set up and transmit the RS for this purpose at the base station. Hereinafter, 'RS for RRM measurement including beam forming gain' is referred to as 'RRM-RS'.

Method M100 and method M101 are methods for utilizing existing RSs as RRM-RSs.

Specifically, method M100 is a method of using all or part of CSI-RS used for CSI measurement as RRM-RS. The method M101 is a method of using a DS (discovery signal) based on CSI-RS, which is used for small cell discovery, as an RRM-RS.

The RRM-RS may be referred to as a cell-specific or user-equipment-specific RRM-RS so that a terminal belonging to its own station or a terminal belonging to another cell can establish RRM-RS and perform RRM measurement using the RRM- specific, or terminal group-specific. Here, the other cell may include a neighbor cell, a neighbor cell, or the like for the serving cell.

Although the base station sets the RRM-RS to be cell-specific or terminal group-specific, the form of signaling it to the terminal may include terminal-specific signaling.

In the method M100, the base station sets and transmits CSI-RS based RRM-RS based on PCI (physical cell ID) and transmits CSI-RS based RRM-RS based on VCI (virtual cell ID) .

As a CSI-RS setting for CSI measurement, a PCI-based CSI-RS is set in the 3GPP Release-10 terminal, and a CSI-RS based on VCI (PCI is possible) can be set in the 3GPP Release-11 and later terminals have.

The CSI-RS configuration for CSI measurement may include a scrambling ID used for sequence generation, and an antenna port number. Here, the scrambling ID is omitted from the resource setting when it is generated based on the PCI, and included in the resource setting when generated based on the VCI. That is, when the scrambling ID is generated based on the VCI, the scrambling ID is set as the VCI.

The CSI-RS configuration for CSI measurement may include a resource configuration for setting the RE location of the RS in resource grids across two slots in a subframe. Herein, the resource grid is a term defined in the 3GPP TS 36.211 standard for expressing a signal transmitted in one slot for each antenna port. The resource grid means a plurality of orthogonal frequency division multiplexing (OFDM) symbols included in one slot and a resource grid including a plurality of subcarriers along a frequency axis for each OFDM symbol. A basic resource unit corresponding to one subcarrier for one OFDM symbol in the resource grid is referred to as an RE (resource element).

The CSI-RS setting for the CSI measurement may include a subframe configuration for setting a transmission period and an offset in units of subframes.

In 3GPP TS 36.211, the CSI-RS configuration unit is defined as 'CSI-RS resource'. The CSI-RS resource in one physical cell may be set for each of the different virtual cells. Here, a virtual cell is co-located, and a signal or channel transmitted by each virtual cell may have different beam directions.

The RRM-RS configuration based on the CSI-RS may also include a scrambling ID (note that the scrambling ID may be omitted if the scrambling ID is limited to be the same as the CSI-RS for CSI measurement), in the same manner as the CSI- RS configuration parameter (which is a parameter for setting the RE location where the CSI-RS is transmitted within the subframe, defined by the CSI-RS configuration in 3GPP TS 36.211), and a subframe configuration Which may include subframe units or periods and offsets in units of milliseconds). The RRM-RS configuration unit thus defined is defined as an 'RRM-RS resource'.

When a part of the CSI-RS used in the CSI measurement is used as the RRM-RS, the resources of each antenna port of the CSI-RS according to the RRM-RS setting are allocated to each antenna port of the CSI- Can be set to overlap resources. As a time resource configuration for this, the transmission period of the RRM-RS can be limited to an integer multiple of the transmission period of the CSI-RS for CSI measurement, and / or the two RSs (RRM-RS, CSI-RS) Lt; / RTI > can be limited to be the same. Also, as a resource setting on the resource grid, all or a part of CSI-RS antenna ports for CSI measurement can be selected and set as an RRM-RS antenna port. To this end, the number of RRM-RS antenna ports may be set to be less than or equal to the number of CSI-RS antenna ports for CSI measurements. The RE location configuration of the RRM-RS and the CSI-CSI for the CSI measurement, so that the RE location of each RRM-RS antenna port in the resource grid can overlap with the RE location of any one of the CSI- The RE location configuration of the RS may be set.

The setting of the resource of the RRM-RS antenna port to be included in the resource of the CSI-RS antenna port for CSI measurement is advantageous in that no additional rate matching or puncturing is required for the RRM-RS resource Lt; / RTI >

Meanwhile, when a plurality of CSI-RS resources are set in one physical cell, the RRM-RS may be configured to have a plurality of RRM-RS resources corresponding to all or a part of a plurality of CSI-RS resources . According to the current 3GPP Release-12 specification, it is possible to set one CSI-RS resource individually through each CSI process using multiple CSI processes. Each CSI-RS resource may correspond to a virtual cell.

At this time, the resources of each antenna port belonging to one RRM-RS resource can be set to overlap resources of each antenna port belonging to one CSI-RS resource.

The base station can set a part of the CSI-RS to be transmitted for the CSI measurement of the terminal belonging to the base station as a CSI-RS based RRM-RS. For example, in a full-dimension (FD) -MIMO, a base station transmits CSI-RS at CSI-RS antenna ports for a vertical domain or CSI-RS antenna ports for a horizontal domain RS-based RRM-RS transmission can be established only for the CSI-RS antenna ports corresponding to the vertical domain. In step M101, when the base station sets up the RRM-RS using the CSI-RS based DS of 3GPP Release-12, the setting information thereof includes the period and offset of discovery measurement timing configuration (DMTC), DS occasion duration, (NZP) non-zero-power CSI-RS (for discovery) resource configuration list. Here, each CSI-RS resource configuration in the CSI-RS resource configuration list may include ID (s) for distinguishing the CSI-RS resource configuration.

In the NZP CSI-RS resource configuration, an ID for identifying a CSI-RS resource configuration, a PCI of a cell transmitting the NZP CSI-RS, a scrambling ID of the corresponding NZP CSI-RS, and an RE position of the corresponding NZP CSI- And a subframe offset indicating the relative location of the corresponding NZP CSI-RS within the DS interval. The subframe offset may be defined as a subframe offset between a secondary synchronization signal (SSS) of a cell corresponding to the PCI of the cell transmitting the corresponding NZP CSI-RS and a corresponding NZP CSI-RS resource in the DS interval .

The DMTC is used to inform the UE of the position of a subframe to perform discovery measurement. The DMTC has a length of 6 ms, and within the DMTC the DS is transmitted with a DS occasion duration length expressed as a number of subframes.

The DS is composed of a period having a duration of 1 to 5 consecutive subframes in frame structure type 1 and a period having a duration of 2 to 5 consecutive subframes in frame structure type 2, . The DS may include CRS, primary synchronization signal (PSS), SSS, and NZP CSI-RS (for discovery).

PSS is located in the first subframe of DS section in frame structure type 1 and in the second subframe of DS section in frame structure type 2.

The SSS is located in the first subframe of the DS section.

The CRS is located in the downlink pilot time slot (DwPTS) of all DL (downlink) subframes or special subframes.

As described above, the NZP CSI-RS is located in a subframe away from the SSS by a subframe offset included in the NZP CSI-RS configuration among the subframes within the DS interval.

One physical cell may have a plurality of virtual cells and an NZP CSI-RS (for discovery) may be set for each virtual cell.

Meanwhile, the base station can apply the virtualization of the antenna port of the RRM-RS fixedly or change the virtualization according to the time. In the case where the base station changes and applies virtualization according to time, the virtualization change pattern may be defined in advance for the base station and the terminal, or the base station may transmit the change pattern information to a radio resource control (RRC) message, a RRC signaling, a media access control ) Message, MAC signaling, or PHY signaling.

 The virtualization of the RRM-RS antenna port can be set to match the virtualization of the CSI-RS antenna port. The virtualization of each RRM-RS antenna port can be set to be all or part of every CSI-RS antenna port. Or the virtualization of the RRM-RS antenna port may be applied such that the beam by virtualization of the RRM-RS antenna port includes a plurality of beams (or spans a plurality of beams) by virtualization of a plurality of CSI-RS antenna ports .

The RRM measurement includes not only the measurement for the serving cell but also the measurement for the other cell. Therefore, in order for the UE to perform RRM measurement based on the RRM-RS of another cell, the RRM-RS configuration of the other cell can be received from the serving cell base station. This can be included in the RRM measurement and reporting setup described below.

In the case where each base station changes the RRM-RS setting dynamically or quasi-statically, each base station can update the configuration information changed by the neighbor base station through the inter-base station signaling. If dynamic or quasi-stationary signaling between base stations is not possible for the RRM-RS setup, each base station sets the RRM-RS to static or static and transmits RRM-RS configuration information of other cell base stations to operations, administration and management ). ≪ / RTI >

2. ' Beam forming  Including gain RRM  How to set up measurement and reporting

The base station includes the RRM measurement and reporting configuration in the RRC message and transmits it to the terminal. The UE receives the RRM measurement and report configuration included in the RRC message from the base station, performs RRM measurement based on the RRM measurement, and reports the RRM measurement result to the base station.

Alternatively, in an initial access procedure prior to acquiring an RRC message, the base station may include RRM measurement and reporting settings in a system information block (SIB) and transmit it to the UE for 'RRM measurement including beamforming gain'. The terminal receives the RRM measurement and report settings included in the SIB from the base station, and performs RRM measurement and reporting based on the RRM measurement and report setting.

FIG. 1 is a diagram illustrating a method for performing RRM measurement and reporting including beam forming gain using an RRM-RS according to an embodiment of the present invention. Referring to FIG.

Specifically, FIG. 1 shows a flow between a serving cell, another cell, and a terminal for RRM measurement and reporting including beamforming gain.

The serving cell (or serving base station, hereinafter collectively referred to as 'serving cell') sets RRM measurement and reporting including 'beamforming gain' to the UE through RRC signaling (SlO).

The serving cell transmits an RRM-RS to the UE according to the setting (S11). In addition, another cell (also referred to as another cell) transmits the RRM-RS to the UE according to the corresponding setting (S13).

The UE receives the RRM-RS from the serving cell or another cell according to 'RRM measurement and report including the beamforming gain' set through RRC signaling, and performs RRM measurement including the beamforming gain (S12 and S14 ). Specifically, the UE measures 'RRM including beam forming gain' only when the CRS-based RRM measurement result satisfies the start condition (hereinafter referred to as 'first condition') of 'RRM measurement including beam forming gain' .

The mobile station reports the result of the RRM measurement including the beamforming gain to the base station (S15). Specifically, the UE may periodically report the result of the RRM measurement including the beamforming gain and / or the CRS-based RRM measurement result to the base station. Alternatively, if the result of the RRM measurement including the beamforming gain satisfies a reporting event condition (hereinafter referred to as 'second condition') described below, or if the CRS-based RRM measurement result satisfies the second condition, RRM measurements including beamforming gain ' and / or CRS-based RRM measurements to the base station.

The RRM measurement and reporting settings may include all or some of the configuration information illustrated in Table 1 below.

Setting information Remarks Information on whether to measure RRM including beam forming gain It may be unnecessary to measure the RRM including the beam forming gain depending on the capability of the UE, the configuration of the cellular network (topology or layout), or the location of the UE in the cell. Conditions for triggering RRM measurement including beam forming gain This is a condition for allowing the UE to perform RRM measurement including the beam forming gain only for cells whose CRS-based RRM measurement value is equal to or higher than a certain reference value. The setting for the condition may include the reference value (or limit value) necessary to compare the condition. List of PCIs in other cells where RRM measurement needs to be performed - The carrier frequency or bandwidth information of the other cell for which the RRM measurement needs to be performed This is necessary for the RRM measurement of inter-frequency cells. 'Method of measuring RRM including beam forming gain' This may be an indication of whether the RRM measurement including the beamforming gain is to be measured based on the RRM-RS or based on the provision of the beamforming gain information of the base station.
Such indication information may be included in all of the cells of the RRM measurement object in the RRM measurement and report setting, or may be included in each cell of the RRM measurement object (including the serving cell or the other cell). RRM-RS setting information When the UE needs to perform the RRM-RS based RRM measurement, the base station must inform the UE of the RRM-RS setup information.
The RRM-RS configuration information of the serving cell or other cell for which RRM-RS based RRM measurement is required may be included in the RRM measurement and report setting. This has been described above in the description of method M100 and method M101. RRM-RS based RRM measurement method information Depending on the virtualization or beam-forming direction characteristics of the RRM-RS antenna port, the RRM measurement method may be different, so a setting is required.
The RRM-RS based RRM measurement method may include all or some of methods M310, M311, M312, and M313 described below. Among these methods, the method that the UE should use may be included in the RRM measurement and report setting.
In the case of method M311 or method M312, the M-information of Best-M may be defined in advance or additionally included in the RRM measurement and report setting. The beamforming gain information provided by the base station In the case where the UE must perform RRM measurement based on the provision of the beamforming gain information of the base station, the beamforming gain information for the serving cell or the other cell may be included in the RRM measurement and report setting.
As such information, the beamforming gain value in dB can be included in the RRM measurement and reporting settings. L3 (layer 3) filter coefficients for 'RRM measurement with beam forming gain' This can be used for weighting L1 (layer 1) measurements and past L3 measurements when the terminal performs L3 filtering. Event-triggered-based RRM measurement Event criterion for reporting of thresholds (or thresholds) This may include the A1a reference value, the A2a reference value, the A3a reference value, the A4a reference value, the A5a1 reference value, the A5a2 reference value, the A6a reference value, the B1a reference value, the B2a1 reference value, and the B2a2 reference value, which will be described later.
The comparison reference value of the event condition may be set differently for each cell. Period (or reporting interval) for periodic RRM measurement reports or multiple RRM measurement reports. A reporting time interval for periodic RRM measurement reporting can be set.
Alternatively, for multiple reports in an Event-triggered based RRM measurement report, the time interval between reports can be set. In an event-triggered periodic RRM measurement report, the offset from the time the RRM measurement report start condition is met to the start of the RRM measurement report - In an event-triggered based RRM measurement report, the hysteresis margin used for the event condition - RRM Measurement Report Count In a periodic RRM measurement report or an event-triggered based RRM measurement report, the UE can report up to the set number of reports. The number of physical cells or virtual cells (N) of an RRM measurement report object, This can be used in one RRM measurement report, where a CRS-based or RRM-RS based RRM measurement is intended to be reported only by the base station for measurement results for the N largest physical cells.
Here, the CRS-based or RRM-RS based RRM measurement value may be a value based on one kind of value when the terminal obtains plural kinds of measured values.

The beamforming gain information provided by the base station, which may be included in the RRM measurement and reporting settings, is determined by the base station transmitting the information, such as the antenna array configuration (e.g., antenna array size, TXRU number, antenna height, RSRP and RSRQ as reported by the UE, CSI (e.g., all or some of the rank indicator, precoding matrix indicator (PMI), and channel quality indicator (CQI)) reported by the terminal, SRS sounding reference signal, or a combination of all or some of them, by estimating the beam forming gain.

The base station can receive the antenna array configuration information of the other cell through the OAM.

The base station may include the RRM measurement and report setup information in an RRC message or an SIB message to the UE.

When the RRM measurement and report setting needs to be changed, the base station may include the changed RRM measurement and report setting information in the RRC message or the SIB message to reset the RRM measurement and report setting information.

When the terminal receives an RRC message or an SIB message related to the RRM measurement, it can set or reset the RRM measurement and report setting information accordingly.

3. ' Beam forming  Including gain RRM  Method of measurement '

FIG. 2 is a diagram illustrating a method of performing RRM measurement and reporting including a beamforming gain according to another exemplary embodiment of the present invention. Referring to FIG.

The UE performs CRS-based RRM measurement according to RRM measurement and report setting by RRC signaling from the serving cell and performs RRM measurement including beam forming gain (S20 to S22).

Specifically, the UE can perform CRS-based RRM measurement by receiving a CRS of a serving cell or another cell (S20). S20 may be omitted.

In the case where the UE performs the 'RRM measurement including the beamforming gain', the UE can unconditionally perform this measurement. Alternatively, the UE may perform 'RRM measurement including beamforming gain' when the result of the CRS-based RRM measurement satisfies a certain condition (first condition) (S21).

Next, the UE receives the set RRM-RS (e.g., RRM-RS of the serving cell and RRM-RS of the other cell) and performs 'RRM measurement including the beamforming gain' The RRM measurement including the beam forming gain may be performed (S22).

If the UE determines that the value of the CRS-based RRM measurement or the value of the RRM measurement including the beamforming gain meets the reporting event condition (S23) The result of the CRS-based RRM measurement is reported to the serving cell (S24). Step S23 may be omitted.

In a case where the result of the CRS-based RRM measurement satisfies a certain condition (first condition), when the UE performs the RRM measurement including the beam forming gain, information related to the first condition (e.g., RSRP reference value, RSRQ reference value , A reference value for the difference from the maximum RSRP, a reference value for the difference from the maximum RSRQ, etc.) may be included in the configuration information for the RRM measurement and reporting (hereinafter, referred to as 'RRM measurement and reporting configuration information') or may be defined in advance. Specifically, the first condition may include a case where the RSRP of the cell is equal to or greater than the first reference value, or a case where the RSRQ of the cell is equal to or greater than the second reference value. Alternatively, the first condition may include a case where the RSRP of the corresponding cell is less than or equal to a third reference value, or a case where the RSRQ of the corresponding cell is less than or equal to a fourth reference value than the RSRQ having the largest RSRP. Here, all or some of the first reference value, the second reference value, the third reference value, and the fourth reference value may have the same value.

The UE performs 'RRM measurement including beam forming gain' according to the RRM measurement and report setting information acquired from the base station. In particular, the method for " RRM measurement including beam forming gain " may include methods M300, M301, and M302.

Method M300 is a method for performing RRM-RS-based RRM measurement. Method M301 is a method in which the base station adds the beam forming gain informed by CRS-based RRM measurement through signaling. Method M302 is a method of mixing method M300 and method M301.

For the method M300, the UE receives the RRM-RS according to the RRM-RS setting information of each cell and measures RSRP or RSRQ using the 'RRM-RS setting information of each cell for' RRM measurement including the beamforming gain '. The RRM-RS based RSRP measurement method may include method M310, method M311, method 312, and method 313.

Method M310 calculates the RSRP for each RRM-RS antenna port for each physical cell or virtual cell that is the subject of 'RRM measurement including beamforming gain', and uses the largest value of RSRP.

Method M311 determines the RSRP value of all or Best (eg, in order of increasing RSRP) -M RRM-RS antenna ports for each physical cell or virtual cell subject to RRM measurement including the beamforming gain Watt). ≪ / RTI >

Method M312 may be performed on all or Best (eg, in order of increasing RSRP) -M RRM-RS antenna ports (or for each virtual cell corresponding to each virtual cell) for each physical cell or virtual cell subject to RRM measurement including ' RRM-RS antenna port) RSRP value (e.g., in units of Watt).

The method M313 calculates RI or PMI from a channel corresponding to a plurality of RRM-RS antenna ports for each physical cell or virtual cell that is a target of 'RRM measurement including beam forming gain', calculates an RSRP for an effective channel to which the RI or PMI is applied, , And the calculated RSRP is used. The method M313 calculates an RSRP (e.g., a unit of Watt) for an effective channel corresponding to each spatial layer set for one physical cell or a virtual cell when the rank corresponding to the RI is greater than 1, And using a linear sum as the RRM measurement. In a case where a dual codebook is used, the UE may divide the PMI into first PMI and second PMI at the time of CSI feedback and perform feedback simultaneously or temporally. In the case where a dual codebook is used, the PMI used to obtain the RRM measurement value may be composed of first PMI, or a combination of first PMI and second PMI.

If the PMI is composed only of the first PMI, the UE calculates an RRM measurement value (for example, the linear sum of the RSRPs for the effective channel corresponding to each spatial layer described above) for all second PMIs belonging to the first PMI, And the average value can be used as the RRM measurement value. If the PMI is composed of a combination of the first PMI and the second PMI, the UE uses the corresponding RRM measurements (for example, the linear sum of RSRPs for the effective channel corresponding to each spatial layer described above) .

The RSRP of one RRM-RS antenna port can be defined as the linear average of the power contributions of the RE transmitting the RRM-RS antenna port within the measurement bandwidth. By combining the RSRPs of the receiving antenna paths having a plurality of receiving antennas of the UE, an RRM measurement value can be obtained.

Also, in order to obtain RSRP (e.g., RSRP per spatial layer) in method M313, a UE performs channel estimation (e.g., CSI-RS RE pair unit, PRB (physical resource block) unit, Or subband unit), and obtain RI or PMI for each estimated channel sample. Then, the terminal multiplies the estimated channel matrix by the precoding matrix corresponding to RI or PMI to obtain an effective channel matrix, obtains a channel gain for channel vectors corresponding to each layer, and calculates a channel for a plurality of estimated channel samples The gain can be averaged in linear units or dB units to obtain the RSRP in method M313.

The RSRQ based on the RRM-RS multiplies the RB (proportional to the system bandwidth) by an RB (e.g., a unit of Watt) based on the RRM-RS and outputs the received signal strength indicator (RSSI) Yes, the unit is divided by Watt).

The CSR-based RSSI may follow the definition of the 3GPP TS 36.214 standard.

The RSRP or RSRQ based on the RRM-RS may be converted in units of dB in L3 filtering or reporting.

For the method M301, the UE determines whether the corresponding cell included in the RRM measurement and report setting information in the CRS-based RSRP measurement value (e.g., dBm) or the RSRQ measurement value (e.g., in dB) The beamforming gain (in dB) provided by the base station can be added.

On the other hand, Method M302 is a method of mixing Method M300 and Method M301. For example, the UE may perform measurements using the method M300 for the serving cell and perform measurements using the method M301 for the other cell. For example, the UE may perform the measurement using the method M300 only for the serving cell and some selected other cells, and perform the measurement using the method M301 for the remaining cells.

Measurements according to methods M300, M301, and M302 may be measurements at L1 level. The terminal may report the measurement value of the L1 level itself or the L3 level measurement by taking L3 filtering based on the measurement value of the L1 level. The L3 filtering may include a sum of a value obtained by multiplying the measured value of the L1 level by the first weight and a value obtained by multiplying the previous L3 measured value by (1 - first weight). The L3 filter coefficients associated with the first weight may be included in the RRM measurement and reporting configuration information. In performing the L3 filtering, the UE can reset the L3 filtering when the RRM measurement and report setting information is reset.

4. ' Beam forming  Including gain RRM  How to report "measurement"

When the terminal obtains the RRM measurement value as described above, it reports it to the base station.

The RRM measurement report may include methods M400, M401, and M402.

The method M400 is a method in which the terminal periodically reports according to the period set by the base station. The method M401 is a method of reporting when the terminal meets the reporting event condition set by the base station. Method M402 is a method of mixing methods M400 and M401.

The offset from the reporting period of the 'RRM measurement including beam forming gain' method M400 or method M402 or the 'after the RRM measurement report start condition is satisfied to the starting point of the RRM measurement report' is set to the set values of the CRS based RRM measurement report . ≪ / RTI >

The reporting event condition (second condition) in method M401 or method M402 may include an event condition of the CRS-based RRM measurement report and / or an event condition of the RRM-RS based RRM measurement report described below.

If the measurement result satisfies the reporting event condition for the CRS-based RRM measurement, the UE can report the value of the 'RRM measurement including beam forming gain' together with the CRS-based RRM measurement values. The event conditions for the CRS-based RRM measurement report may follow Event A1, Event A2, Event A3, Event A4, Event A5, Event A6, Event B1, and Event B2 of the 3GPP TS 36.311 document. Or if the measurement result satisfies the event condition for the CRS-based RRM measurement report and additionally satisfies the event condition for the report of the " RRM measurement including beamforming gain ", the UE, together with the CRS-based RRM measurement values, The value of 'RRM measurement including beam forming gain' can be reported. Here, the event conditions for the report of the " RRM measurement including the beamforming gain " may include the information illustrated in Table 2 below.

Event condition Remarks Event A1a If the measured value for the serving cell is greater than the A1a reference value Event A2a If the measured value for the serving cell is smaller than the A2a reference value Event A3a If the measured value for the other cell is larger than the measured value for the serving cell (for example, PCell at the time of carrier aggregation) by more than the A3a reference value Event A4a When the measured value for the other cell is larger than the reference value of A4a Event A5a If the measured value for the serving cell (e.g., PCell at the time of carrier aggregation) is less than the A5a1 reference value and the measured value for the other cell is greater than the A5a2 reference value Event A6a If the measured value for the other cell is larger than the measured value for SCell by more than the reference value of A6a Event B1a If the measured value for the inter-RAT other cell is greater than the B1a reference value Event B2a When the measurement value for the serving cell (e.g., PCell at the time of carrier aggregation) is smaller than the reference value of B2a1 and the measured value for the other cell of Inter-RAT is larger than the reference value of B2a2

The method M402 may include periodically performing an RRM measurement report while the UE continues to receive the event (the measurement result satisfies the event condition) after the measurement result satisfies the event condition. For this, the measurement result satisfying the event condition may be defined as an entering condition of the RRM measurement report, and the measurement result does not satisfy the event condition is defined as a leaving condition of the RRM measurement report. .

It may be considered to include the hysteresis margin in the start and end conditions of the RRM measurement report in order to prevent frequent occurrence of the start and end of the RRM measurement report in the RRM measurement report according to this reporting event condition .

If the measured value is considered as an event condition, the starting condition of the RRM measurement report can be defined as the case where the measured value plus hysteresis margin is greater than the reference value, and the RRM measurement report The termination condition can be defined as a case where the measured value minus the hysteresis margin is smaller than the reference value. For example, a start condition including a hysteresis margin for Event A1a may be defined as a case where a value obtained by adding a hysteresis margin to a measured value for a serving cell is larger than the A1a reference value, May be defined as a case where the value obtained by subtracting the hysteresis margin from the measured value for the serving cell is smaller than the A1a reference value.

If the measurement is considered to be an event condition when the measured value is smaller than the reference value, the starting condition of the RRM measurement report can be defined as a case where the measured value minus the hysteresis margin is smaller than the reference value, The termination condition can be defined as the case where the measured value plus hysteresis margin is greater than the reference value. For example, a start condition including a hysteresis margin for Event A2a may be defined as a case where a value obtained by subtracting a hysteresis margin from a serving cell measurement value is greater than an A2a reference value, And a value obtained by adding a hysteresis margin in the cell measurement value is smaller than the A2a reference value.

If a plurality of conditions are considered as an event condition, a hysteresis margin can be considered for each condition, as described above.

If the measurement result meets the reporting event condition (corresponding to method M401), or if the measurement result meets the RRM measurement report start condition during the reporting event condition (Corresponding to method M402) until the reporting time of the cycle arrives until the RRM measurement report termination condition is satisfied.

If the number of RRM measurement reports is set in method M400, method M401, or M402, if the measurement result for each method satisfies the reporting condition of each method and the reporting is completed for the number of times of reporting the corresponding RRM, Can be terminated. If the measurement result does not satisfy the reporting condition of each method (or if the measurement result satisfies the reporting termination condition) for each method, even if the reporting by the number of reporting times is not completed, the terminal ends the reporting in advance . If a plurality of reports are allowed for each method, the time interval (or reporting period) between reports may follow the set values described above. The RRM measurement reporting method may include methods M410 and M411, depending on the type of measurement being reported.

Method M410 is a method for reporting CRS-based RSRP, CRS-based RSRQ, RSRP including beamforming gain, or RSRQ including beamforming gain. Method M411 is a method for reporting the difference between a CRS-based RSRP, a CRS-based RSRQ, a difference between a RSRP with a beamforming gain and a CRS-based RSRP, or between a RSRQ including a beamforming gain and a CRS-based RSRQ.

The difference between the RSRP including the beamforming gain and the CRS-based RSRP can be found by the difference between the former and the latter in dBm, and the difference between the RSRQ including the beamforming gain and the CRS-based RSRQ is And the latter can be obtained.

If only one RRM-RS is configured in the physical cell, then for only the N largest CRS-based RRM measurements (eg, using one of RSRP and RSRQ) Values and RRM-RS-based RRM measurements. RRM-RS based RRM measurements (e.g., using one of the measurements for RSRP and one of the measurements for RSRQ) is the largest N (RRM-RS) in a physical cell, Only the UE can report CRS-based RRM measurements and RRM-RS-based RRM measurements.

When RRM-RS for a plurality of virtual cells is set in a physical cell, RRM-RS-based RRM measurement values (e.g., measurement values relating to RSRP and measurement values related to RSRQ) Only for the Ns with the greatest number of RRM-based RRM measurements (e.g., RSRP or RSRQ), the UE reports the RRM-based RRM measurement values only for the N largest number of RRM- Can report CRS-based RRM measurements.

In method M410 or M411, when the UE reports the CRS-based RRM measurement value, it can report the PCI of the measurement report cell together, and when reporting the RRM-RS based RRM measurement value, (For example, the case where a sequence of RRM-RS is generated based on PCI or a case where PCI is included in RRM-RS setting) or a VCI (for example, a sequence of RRM-RS is generated based on VCI) ) Can be reported together.

If the UE reports a CRS-based RRM measurement value and a RRM-RS based RRM-RS-based RRM measurement value on a PCI-to-PCI basis, the PCI reports only one . In addition, the UE reporting the RRM-RS-based measurement value can transmit the channel direction information (CDI) in addition to the RRM measurement report. The CDI is used to identify the RRM-RS antenna port index (s) corresponding to the beam (e. G., The beam index) corresponding to the beam (e. G., Including horizontal or vertical beams) selected when the terminal measures RSRP or RSRQ based on RRM- ), A combination of PMI (eg, including horizontal, vertical, or joint domain PMI), RI (eg, horizontal, vertical, or joint domain RI), or a combination of RI and PMI .

If the CDI is included in the RRM measurement report, the CDI in the CSI measurement report can be excluded.

The terminal can perform CSI measurement and reporting based on the CDI included in the RRM measurement report. The base station can set it to the terminal. When the base station sets it, the terminal can perform the CSI measurement and report based on the CDI included in the RRM measurement report according to the setting. The setting of the base station can be included in the RRC message or the SIB message.

For example, the UE may include the PMI for the vertical direction in the RRM measurement report as the CDI, and the PMI and CQI for the horizontal direction based on the PMI for the vertical direction at the time of the CSI measurement. For example, the UE may include the first PMI for the vertical direction in the RRM measurement report as the CDI, and the second PMI for the vertical direction based on the first PMI for the vertical direction in the CSI measurement, PMI (or first PMI and second PMI for the horizontal direction), and CQI.

5. When the base station is' Beam forming  Including gain RRM How to use

A base station may trigger a handover by using a CRS-based RRM measurement and a RRM measurement including a beamforming gain, or may add, change (reset) a secondary cell (SCell) at a carrier aggregation (Removed).

The base station can set the cell having the highest value of the 'RRM measurement including the beam forming gain' as the target cell among the cells having the CRS-based RRM measurement satisfying the required level.

The base station can add a cell having the highest value of 'RRM measurement including beam forming gain' among cells having CRS-based RRM measurement satisfying the required level to the SCell.

When the RRM-RS is set based on the VCI and the VCI corresponds to the beam in the specific direction, the base station notifies the terminal of the selected beam only by the CSI CSI-RS for measurement can be set.

6. The base station and the terminal performing the above-

3 is a diagram illustrating a base station according to an embodiment of the present invention.

Specifically, FIG. 3 illustrates a base station 100 that transmits the above-described RRM measurement and report setup information, or RRM-RS.

The base station 100 illustrated in FIG. 3 includes a radio frequency (RF) converter 130, a processor 110, a memory 120, and an antenna module 140.

The processor 110 may be configured to implement the functions, procedures, and methods described herein in connection with a base station. In addition, the processor 110 can control each configuration of the base station 100.

The memory 120 is coupled to the processor 110 and stores various information related to the operation of the processor 110. [

RF converter 130 is coupled to processor 110 and transmits or receives radio signals. In detail, the RF converter 130 may include a transmitting module 131 and a receiving module 132.

The base station 100 receives the RRM measurement report from the terminal through the receiving module 132. [

The base station 100 stores information (or information set for RRM measurement and reporting) necessary for RRM measurement and report setting and RRM measurement values reported from the terminal to the memory 120.

The base station 100 performs RRM measurement and report setting suitable for the UE according to the methods described in the present invention through the processor 110 and performs handover procedures using the RRM measurement values reported from the UE, SCell management, and virtual cell management with beamforming can be performed.

When the RRM-RS is set according to the RRM measurement and report setting information, the base station 100 transmits the RRM-RS through the transmission module 131.

4 is a diagram illustrating a terminal according to an embodiment of the present invention.

Specifically, FIG. 4 illustrates the terminal 200 reporting the RRM measurement and the RRM measurement described above.

The terminal 200 illustrated in FIG. 4 includes an RF converter 230, a processor 210, a memory 220, and an antenna module 240.

The processor 210 may be configured to implement the functions, procedures, and methods described herein in connection with a terminal. In addition, the processor 210 can control each configuration of the terminal 200. [

The memory 220 is coupled to the processor 210 and stores various information related to the operation of the processor 210. [

The RF converter 230 is connected to the processor 210 and transmits or receives a radio signal. Specifically, the RF converter 230 may include a transmitting module 231 and a receiving module 232. [

The terminal 200 receives the RRM measurement and report setting information from the base station 100 through the reception module 232 and receives the RRM-RS when CRS and RRM-RS are set.

The terminal 200 stores the received RRM measurement and report setting information in the memory 220.

When the CRS and the RRM-RS are set, the terminal 200 obtains the RRM measurements from the RRM-RS via the processor 210 according to the methods described herein. The terminal 200 stores the measured RRM values in the memory 220 by the processor 210.

The terminal 200 performs, via the processor 210, a report on the RRM measurements stored in the memory 220, according to the methods described herein.

The terminal 200 transmits an RRM measurement value to be reported to the base station 100 through the transmission module 231. Here, the RRM measurement value may include a CRS-based RRM measurement value and an RRM measurement value including a beam forming gain.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (1)

A method for measuring radio resource management (RRM)
Receiving at least one of a CSI-RS (reference signal) for channel state information (CSI) measurement and a DS (discovery signal) for small cell search as an RRM-RS;
Measuring an RRM reflecting a beamforming gain using the RRM-RS; And
Reporting the result of the RRM measurement reflecting the beamforming gain to the serving base station
Gt; RRM < / RTI >

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