KR20130036383A - Apparatus and method for controling uplink transmission power in wireless communication system - Google Patents

Abstract

The present invention relates to an apparatus and method for controlling uplink transmission power in a wireless communication system.
In the present specification, in a PL measurement section in which a terminal is designated to measure an uplink path loss value, calculating an uplink path loss value, calculating an uplink transmission power based on the uplink path loss value, and uplink. Disclosed is a method of controlling uplink transmission power for a terminal, the method including transmitting a link signal according to the uplink transmission power.
According to the present invention, in the cooperative multi-point communication environment, the path loss value of each uplink receiving point can be independently measured, and the uplink transmission power is estimated by inferring the uplink path loss values of the entire uplink receiving points. Can be controlled.

Description

Apparatus and method for controlling uplink transmission power in a wireless communication system {APPARATUS AND METHOD FOR CONTROLING UPLINK TRANSMISSION POWER IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to wireless communication, and more particularly, to an apparatus and method for controlling uplink transmission power in a wireless communication system.

In order to increase the performance and communication capacity of a wireless communication system, multi-cell cooperation has been introduced. Multi-cell coordination is also referred to as cooperative multiple point transmission and reception (CoMP).

CoMP includes a beam avoidance technique in which neighboring cells cooperate to mitigate interference to a user at a cell boundary, and a joint transmission technique in which neighboring cells cooperate to transmit the same data.

Next-generation wireless communication systems, such as Institute of Electrical and Electronics Engineers (IEEE) 802.16m or 3rd Generation Partnership Project (3GPP) long term evolution (LTE) -Advanced, are located at cell boundaries and are subject to severe interference from adjacent cells. In order to solve this problem, CoMP can be considered.

Various scenarios are possible with this CoMP. There is an intra-site CoMP with multiple cells around one base station, and a plurality of high-power remote radio heads (RRHs) around one macro cell. There are high-power RRH CoMPs that exist, and low-power RRHs exist around one macro cell, but the cell IDs of the RRHs and the cell IDs of the macro cells are not the same. There is a low power RRH CoMP.

When the terminal performs uplink transmission for one or more transmission / reception points operating in CoMP, a criterion for determining the uplink transmission power has not yet been determined.

An object of the present invention is to provide an apparatus and method for controlling uplink transmission power in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for operating in a muting mode in a PL measurement section.

Another object of the present invention is to provide an apparatus and method for obtaining an uplink path loss value using a reference signal received in a PL measurement section.

Another technical problem of the present invention is to provide an apparatus and method for calculating an uplink path loss value for each transmit / receive point in a cooperative multipoint scheme in which a plurality of transmit / receive points communicate with a terminal.

According to an aspect of the present invention, there is provided a control method of uplink transmission power for a terminal performed by a terminal. The method includes the steps of calculating, by the terminal, an uplink path loss value in a designated PL measurement interval to measure an uplink pathloss (PL) value, and calculating an uplink transmission power based on the uplink path loss value. And transmitting an uplink signal according to the uplink transmission power. The PL measurement interval includes a plurality of subframes, the PL measurement interval includes non-transmission timing at which a sub-transmission point operates in a muting mode, wherein the sub-transmission point is a sub-transmission point for a cell specific reference signal. This mode is set to zero-power.

According to another aspect of the present invention, there is provided a method of controlling uplink transmission power for a terminal performed by a remote radio head. The method may include operating in a muting mode at a non-transmission timing included in a PL measurement interval used for measuring an uplink pathloss (PL) value by the terminal, in the PL measurement interval, in addition to the non-transmission timing. Transmitting a cell-specific reference signal to the terminal at a time point; and receiving, from the terminal, an uplink signal transmitted with uplink transmission power based on an uplink path loss value calculated in the PL measurement interval. .

According to the present invention, in the cooperative multi-point communication environment, the path loss value of each uplink receiving point can be independently measured, and the uplink transmission power is estimated by inferring the uplink path loss values of the entire uplink receiving points. Can be controlled. In addition, estimating uplink path loss using CRS increases the reliability of the measurement compared to using other reference signals such as CSI-RS, and also prevents the decrease in data transmission efficiency due to the overshoot of reference signal transmission. have.

1 is a block diagram showing a wireless communication system to which the present invention is applied.
2 and 3 schematically show the structure of a radio frame to which the present invention is applied.
4 is a flowchart illustrating a method of controlling uplink transmission power for a terminal according to an embodiment of the present invention.
5 is a diagram illustrating a non-transmission timing in a muting period and an offset according to an embodiment of the present invention.
6 is a diagram illustrating non-transmission timing in a PL measurement section according to an embodiment of the present invention.
7 is a flowchart illustrating an operation of measuring, by the terminal, an uplink power loss value using a PL measurement interval according to an embodiment of the present invention.
8 is a diagram illustrating a non-transmission timing in a muting period according to an embodiment of the present invention.
9 is a flowchart illustrating an operation of measuring an uplink power loss value by a terminal according to another embodiment of the present invention.
10 is a flowchart illustrating a method of controlling a transmission of a reference signal in a PL measurement section by a sub transceiver according to an example of the present invention.
11 is an example of a scenario of controlling uplink transmission power according to the present invention.
12 is another example of a scenario of controlling uplink transmission power according to the present invention.
13 is another example of a scenario of controlling uplink transmission power according to the present invention.
14 is a block diagram illustrating a terminal and a transmission and reception point according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to the accompanying drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In addition, in describing the embodiments of the present specification, when it is determined that the detailed description of the related well-known configuration or function may obscure the subject matter of the present specification, the detailed description thereof will be omitted.

The present specification describes a communication network, and the work performed in the communication network is performed in the process of controlling the network and transmitting data in a system (for example, a base station) that manages the communication network, or a terminal linked to the network. Work can be done in

According to embodiments of the present invention, 'transmitting the control channel may be interpreted to mean transmitting control information through a specific channel. Here, the control channel may be, for example, a physical downlink control channel (PDCCH) or a physical uplink control channel (PUCCH).

1 is a block diagram showing a wireless communication system to which the present invention is applied.

Referring to FIG. 1, a wireless communication system 10 is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system 10 includes at least one base station 11 (BS). Each base station 11 provides a communication service for a particular geographic area or frequency area (generally called a cell) 15a, 15b, 15c. Cells 15a, 15b, and 15c may in turn be divided into a number of regions (called sectors).

The user equipment (UE) 12 may be fixed or mobile, and may include a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, and a PDA. (personal digital assistant), wireless modem (wireless modem), a handheld device (handheld device) may be called other terms. The base station 11 generally refers to a fixed station communicating with the terminal 12, and includes an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and a femto eNB. ), A home eNB (HeNB), a relay, a remote radio head (RRH), etc. may be referred to as other terms. Cells 15a, 15b, and 15c should be interpreted in a comprehensive sense indicating some areas covered by the base station 11, and encompass all of the various coverage areas such as megacells, macrocells, microcells, picocells, and femtocells. to be.

Hereinafter, downlink refers to a communication or communication path from the base station 11 to the terminal 12, and uplink refers to a communication or communication path from the terminal 12 to the base station 11. . In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11. There is no limitation on the multiple access scheme applied to the wireless communication system 10. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA , OFDM-CDMA, and the like. These modulation techniques demodulate signals received from multiple users of a communication system to increase the capacity of the communication system. The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme transmitted using different times or a frequency division duplex (FDD) scheme transmitted using different frequencies.

The wireless communication system 10 may be a Coordinated Multi Point (CoMP) system. The CoMP system refers to a communication system supporting CoMP or a communication system to which CoMP is applied. CoMP is a technique for adjusting or combining signals transmitted or received by multi transmission / reception (Tx / Rx) points. CoMP can increase data rates and provide high quality and high throughput.

The transmission / reception point may be defined as a component carrier or a cell or a base station (macro base station, pico base station, femto base station, etc.), or a remote radio head (RRH). Alternatively, the transmission / reception point may be defined as a set of antenna ports. The transceiver may transmit information about the set of antenna ports to the terminal through radio resource control (RRC) signaling. Therefore, a plurality of transmission points in one cell can be defined as a set of antenna ports. The intersection between the set of antenna ports is always empty.

The base station 11 of the cell 15a, the base station 11 of the cell 15b and the base station 11 of the cell 15c may configure multiple transmission / reception points. For example, the multiple transmit / receive points may be base stations of a macro cell forming a homogeneous network. The multiple transmit / receive points may also be base stations of macro cells and base stations of pico cells within macro cells, forming a heterogeneous network. In addition, the multiple transmission / reception points may be a base station of the macro cell and a remote radio unit (RRU) in the macro cell. In addition, the multiple transmission / reception points may be RRHs belonging to the base station of the macro cell and RRHs belonging to the base station of the heterogeneous cell (e.g. pico cell) in the macro cell.

The CoMP system may selectively apply CoMP. A mode in which a CoMP system performs communication using CoMP is called a CoMP mode, and a mode other than the CoMP system is called a normal mode. For example, if CoMP is determined to be advantageous, the CoMP system may operate in CoMP mode. On the other hand, if CoMP is determined to be disadvantageous, the CoMP system may operate in a normal mode.

The terminal 12 may be a CoMP terminal. The CoMP terminal is a component of the CoMP system and performs communication with a CoMP cooperating set. Like the CoMP system, the CoMP terminal may operate in the CoMP mode or in the normal mode. The CoMP cooperative set is a set of transmit / receive points that directly or indirectly participate in data transmission on a time-frequency resource for a CoMP terminal. For example, the base station 11 of the cell 15a, the base station 11 of the cell 15b, and the base station 11 of the cell 15c may form a CoMP cooperative set. Also, the transmit and receive points do not necessarily have to provide the same coverage. For example, base station 11 of cell 15a may be a base station providing a macro cell, and base station 11 of cell 15b may be an RRH.

Participating directly in data transmission or reception means that the transmitting and receiving points transmit downlink data to the CoMP terminal or receive uplink data from the CoMP terminal. Indirect participation in data transmission or reception means that the transmit / receive points do not transmit downlink data to the CoMP terminal or receive uplink data from the CoMP terminal, but contribute to making a decision about user scheduling / beamforming. .

The CoMP terminal may simultaneously receive signals from the CoMP cooperative set or transmit signals simultaneously to the CoMP cooperative set. At this time, the CoMP system minimizes the interference effect between the CoMP cooperation sets in consideration of the channel environment of each cell constituting the CoMP cooperation set.

When the CoMP terminal performs uplink transmission, a channel environment is formed between the reception point and the CoMP terminal. For example, the channel environment is a set of parameters that affect scheduling for a CoMP terminal, such as a frequency bandwidth allocated to the CoMP terminal and a downlink pathloss (PL). The channel environment is formed individually for each receiving point. This means that the channel environment may be different for each receiving point. If the channel environment is different for each receiving point, the CoMP terminal should set uplink transmission power differently for each receiving point. Therefore, the CoMP terminal needs to know how the channel environment is different for each receiving point.

When operating a CoMP system, various scenarios are possible. The first scenario is an intra-site CoMP scenario in which a plurality of cells exist around one base station. The second scenario is a high-power CoMP scenario in which a plurality of high-power RRHs exist around one macro cell. The third scenario is a CoMP scenario in which a low-power RRH exists around one macro cell but the physical cell ID of the RRH and the physical cell ID of the macro cell are not the same. The fourth scenario is a CoMP scenario in which a low-power RRH exists around one macro cell, but the physical cell ID of the RRH and the physical cell ID of the macro cell are the same. Therefore, in the fourth scenario, the transmission pattern of the reference signal determined by the cell ID also matches.

The transmission and reception point to which the present invention is applied may include a base station, a cell, or an RRH. That is, the base station or the RRH may be a transmission / reception point. Meanwhile, the plurality of base stations may be multiple transmission / reception points, and the plurality of RRHs may be multiple transmission / reception points. Of course, the operation of all base stations or RRH described in the present invention can be equally applied to other types of transmission and reception points.

The layers of the radio interface protocol between the terminal and the base station are based on the lower three layers of the Open System Interconnection (OSI) model, which is well known in the communication system. It may be divided into a second layer L2 and a third layer L3. Among them, the physical layer belonging to the first layer provides an information transfer service using a physical channel.

There are several physical channels used in the physical layer. The PDCCH includes a resource allocation and transmission format of a downlink shared channel (DL-SCH), resource allocation information of an uplink shared channel (UL-SCH), and a physical downlink shared channel. Resource allocation of a higher layer control message such as a random access response transmitted on a PDSCH, a set of transmission power control (TPC) commands for individual terminals in an arbitrary terminal group, and the like. have. A plurality of PDCCHs can be transmitted in the control domain, and the UE can monitor a plurality of PDCCHs.

The control information of the physical layer mapped to the PDCCH is referred to as downlink control information (DCI). That is, the DCI is transmitted on the PDCCH. The DCI may include an uplink or downlink resource allocation field, an uplink transmission power control command field, a control field for paging, a control field for indicating a random access response (RA response), and the like.

DCI has different uses according to its format, and fields defined in DCI are also different. Table 1 shows DCIs according to various formats.

DCI format Explanation 0 Used for scheduling of PUSCH (Uplink Grant) One Used for scheduling one PDSCH codeword in one cell 1A Used for simple scheduling of one PDSCH codeword in one cell and in a random access procedure initiated by a PDCCH command. 1B Used for simple scheduling of one PDSCH codeword in one cell using precoding information 1C Used for brief scheduling of one PDSCH codeword and notification of MCCH changes 1D Used for simple scheduling of one PDSCH codeword in one cell, including precoding and power offset information. 2 Used for PDSCH scheduling for terminals configured in spatial multiplexing mode. 2A Used for PDSCH scheduling of UEs configured in CDD mode with large delay. 2B Used in transmission mode 8 (dual layer transmission) 2C Used in transmission mode 9 (multi-layer transmission) 3 Used to transmit TPC commands for PUCCH and PUSCH with power adjustment of 2 bits 3A Used for transmission of TPC commands for PUCCH and PUSCH with single bit power adjustment. 4 Used for scheduling of PUSCH (uplink grant). In particular, it is used for PUSCH scheduling for terminals configured in the spatial multiplexing mode.

Referring to Table 1, DCI format 0 is uplink scheduling information, format 1 for scheduling one PDSCH codeword, format 1A for compact scheduling of one PDSCH codeword, and very simple A format 2 for scheduling, a format 2 for PDSCH scheduling in a closed-loop spatial multiplexing mode, a format 2A for PDSCH scheduling in an open-loop spatial multiplexing mode, an uplink channel And formats 3 and 3A for the transmission of TPC (Transmission Power Control) commands.

Each field of the DCI is sequentially mapped to _n information bits a ₀ through a _{n -1} . For example, if the DCI is mapped to a total of 44 bits of information bits, each DCI field is sequentially mapped to a ₀ to a ₄₃ . DCI formats 0, 1A, 3, and 3A may all have the same payload size. DCI format 0 may be called an uplink grant.

2 and 3 schematically show the structure of a radio frame to which the present invention is applied.

2 and 3, a radio frame includes 10 subframes. One subframe includes two slots. The time (length) of transmitting one subframe is called a transmission time interval (TTI). Referring to FIG. 1, for example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms.

One slot may include a plurality of symbols in the time domain. For example, in a wireless system using orthogonal frequency division multiple access (OFDMA) in downlink (DL), the symbol may be an orthogonal frequency division multiplexing (OFDM) symbol. Meanwhile, the representation of the symbol period in the time domain is not limited by the multiple access scheme or the name. For example, the plurality of symbols in the time domain may be a Single Carrier-Frequency Division Multiple Access (SC-FDMA) symbol, a symbol interval, or the like in addition to the OFDM symbol.

The number of OFDM symbols included in one slot may vary depending on the length of a cyclic prefix (CP). For example, in case of a normal CP, one slot may include 7 OFDM symbols, and in case of an extended CP, one slot may include 6 OFDM symbols.

One slot includes a plurality of subcarriers in the frequency domain and seven OFDM symbols in the time domain. A resource block (RB) is a resource allocation unit. If a resource block includes 12 subcarriers in the frequency domain, one resource block may include 7 × 12 resource elements (REs).

The resource element represents the smallest frequency-time unit to which the modulation symbol of the data channel or the modulation symbol of the control channel is mapped. If there are M subcarriers on one OFDM symbol, and one slot includes N OFDM symbols, one slot includes MxN resource elements.

In a wireless communication system, it is necessary to estimate an uplink channel or a downlink channel for data transmission / reception, system synchronization acquisition, channel information feedback, and the like. A process of compensating for a distortion of a signal caused by a sudden change in channel environment and restoring a transmission signal is called channel estimation. It is also necessary to measure the channel state of the cell or other cell to which the terminal belongs. In general, a reference signal (RS) known to a terminal and a transceiver is mutually used for channel estimation or channel state measurement.

)를 추정할 수 있다.Since the terminal knows the information of the reference signal, the terminal can estimate the channel based on the received reference signal and compensate the channel value to accurately obtain the data sent from the transmitting and receiving point. If p is the reference signal transmitted from the transmitter / receiver, h is channel information experienced by the reference signal during transmission, n is thermal noise generated at the terminal, and y is the signal received at the terminal, it can be expressed as y = h · p + n. have. In this case, since the reference signal p is already known by the terminal, when the LS (Least Square) method is used, channel information (

) Can be estimated.

는

값에 의존하게 되므로, 정확한 h값의 추정을 위해서는

이 0에 수렴시킬 필요가 있다. 많은 개수의 기준 신호를 이용함으로써

의 영향을 최소화하여 채널을 추정할 수 있다. Here, the channel estimate estimated using the reference signal p

The

Value, so for accurate estimation of the h value

It is necessary to converge to zero. By using a large number of reference signals

It is possible to estimate the channel by minimizing the influence of the channel.

The reference signal may be allocated to all subcarriers or may be allocated between data subcarriers for transmitting data. In a method in which a reference signal is allocated to all subcarriers, a signal of a specific transmission timing is composed of only a reference signal such as a preamble in order to obtain a gain of channel estimation performance. According to a method in which a reference signal is allocated between data subcarriers, a data transmission amount can be increased.

The downlink reference signal includes a cell-specific RS (CRS), an MBSFN reference signal, a UE-specific RS, a positioning reference signal (PRS), and channel state information (CSI). And a reference signal (CSI-RS).

In a multi-antenna system, resource elements used for reference signals of one antenna are not used for reference signals of another antenna. To avoid interference between antennas. For example, only one reference signal may be transmitted per antenna.

The CRS is a reference signal transmitted to all terminals in a cell and used for channel estimation. The CRS may be transmitted in all downlink subframes in a cell supporting PDSCH transmission.

The UE specific reference signal is a reference signal received by a specific terminal or a specific terminal group in a cell, and is mainly used for data demodulation of a specific terminal or a specific terminal group, and thus may be called a demodulation RS (DMRS).

The MBSFN reference signal is a reference signal for providing a multimedia broadcast multicast service (MBMS) and may be transmitted in a subframe allocated for MBSFN transmission. The MBSFN reference signal may be defined only in the extended CP structure.

The PRS may be used for location measurement of the terminal. The PRS may be transmitted only through resource blocks in a downlink subframe allocated for PRS transmission.

CSI-RS may be used for estimation of channel state information. The CSI-RS is arranged in the frequency domain or the time domain. Channel quality indicator (CQI), precoding matrix indicator (PMI) and rank indicator (RI) rank information such as channel quality indicator (CQI), if necessary through the estimation of the channel state using the CSI-RS As reported from the terminal. The CSI-RS may be transmitted on one or more antenna ports.

The uplink path loss value may be estimated based on the CRS or CSI-RS or the sounding reference signal (SRS) or the physical random access channel (PRACH). For example, when measuring the path loss value using the CSI-RS, the base station instructs the terminal of the CSI-RS pattern of the transceiver point, the terminal via the CSI-RS downlink path loss value at each transceiver point We estimate the uplink power loss based on this.

Or, for example, when measuring the path loss value using the SRS or PRACH, the base station calculates the received power difference between the transmission and reception points for the SRS or PRACH transmitted by the terminal, and between the transmission and reception points forming the uplink cooperative set The path loss value is inferred to control the uplink transmission power of the terminal.

However, if the CSI-RS is used for the measurement of the path loss, only one resource element based on antenna port 0 per pair of resource blocks can be used as a sample of the power loss. In addition, given that the transmission period of CSI-RS is 5, 10, 20, 40, 50 ms, the number of samples used to obtain the average value of the path loss is limited, so the reliability of the measured value is low. On the contrary, if the transmission period of the CSI-RS is shortened to increase the reliability of the average value of the path loss, the data transmission efficiency may decrease due to the frequent transmission of the CSI-RS reference signal.

On the other hand, when the UE measures the downlink path loss by using the CRS, 8 resource elements per pair of resource block pairs can be employed as an example of the antenna port 0 as a sample for measuring the path loss. In addition, considering that the CRS is transmitted in every subframe, the number of samples used to obtain the average value of the path loss is sufficient. The specific number of samples may be an implementation issue of the terminal within a range satisfying the accuracy of a given measurement.

4 is a flowchart illustrating a method of controlling uplink transmission power for a terminal according to an embodiment of the present invention.

Referring to FIG. 4, the primary transmit / receive point provides RS scheduling to the secondary transmit / receive point (S400). The primary transmit and receive points and the secondary transmit and receive points form a cooperative set according to the cooperative multipoint method. For example, the primary transmit / receive point and the secondary transmit / receive point may cooperatively receive an uplink signal from the terminal or transmit a downlink signal to the terminal. The primary transmit / receive point may be a macro base station, and the secondary transmit / receive point may be a base station having less coverage than the macro base station, for example, an RRH or a pico base station.

When the reference signal transmitted from the secondary transceiver point to the terminal is the second reference signal, the reference signal scheduling means that the transmission of the second reference signal is scheduled. Transmission timing (timinig) or non-transmission timing of the second reference signal is defined by the reference signal scheduling. The transmission timing refers to the timing at which the secondary transceiver transmits the second reference signal, and the non-transmission timing refers to the timing at which the secondary transceiver does not transmit the second reference signal. Whether the reference signal scheduling defines the transmission timing or the non-transmission timing, the secondary transmission / reception point transmits or does not transmit the second reference signal according to the reference signal scheduling. Hereinafter, it is assumed that reference signal scheduling defines non-transmission timing. However, all embodiments and technical spirits of the present invention described below may be equally applicable to the case in which reference signal scheduling defines transmission timing.

Non-transmission timing may be defined as an offset of every muting period. As an example, the muting period is set to n subframes (n ≧ 1). As another example, the muting period is set in ms. The offset indicates a time point after a certain time from the start of every muting period. 5 is a diagram illustrating a non-transmission timing in a muting period and an offset according to an embodiment of the present invention. Referring to FIG. 5, when the muting period is 10 ms and the offset is 2 ms, the remaining portion except for the offset becomes the non-transmission timing within the PL measurement interval. For example, the non-transmission timing of the sub-receiver point is 2ms, 12ms, 22ms, 32ms,... Which is offset in each PL measurement interval. Except for the remaining time. Although FIG. 5 defines the muting period and the offset in ms unit, this is only an example and the muting period and the offset may also be defined in the subframe unit. All time intervals except the PL measurement interval are transmission timings.

Referring to FIG. 4 again, the secondary transmission / reception point sets non-transmission timing of the second reference signal based on the reference signal scheduling of the primary transmission / reception point (S405).

The main transceiver point transmits the reference signal scheduling information to the terminal (S410). The reference signal scheduling information may be signaling used in an RRC related procedure such as radio resource control (RRC) establishment and RRC reconfiguration. Reference signal scheduling information includes a parameter to be set for the path loss measurement. As an example, the reference signal scheduling information includes information about a muting period and an offset indicating non-transmission timing of the secondary transmission / reception point. As another example, the reference signal scheduling information includes information about the reference signal transmission power of the secondary transmission / reception point. As another example, the reference signal scheduling information includes information about the size of the cooperative set, that is, the number of transmission and reception points included in the cooperative set. As another example, the reference signal scheduling information includes at least one of information on the muting period and the offset of the sub transmission and reception points, information on the reference signal transmission power of the sub transmission and reception points, and information on the size of the cooperative set.

In FIG. 4, step S410 is described as being performed after step S405, but this is only an example, and step S405 and step S410 may be performed simultaneously or step S410 may be performed before step S405.

At the set non-transmission timing, only the main transmission / reception point transmits the main reference signal to the terminal, and the sub transmission / reception point operates in a muting mode (S415). At the transmission timing, the main transmission / reception point transmits the first reference signal and the sub transmission / reception point transmits the second reference signal to the terminal (S420). That is, the secondary transmission and reception point operates in the muting mode at the non-transmission timing, and transmits the second reference signal to the terminal at the transmission timing. The muting mode is a mode in which the secondary transceiver does not transmit the second reference signal. Alternatively, the muting mode is a mode in which the secondary transceiver sets the transmit power of the second reference signal to zero. Muting the second reference signal may be referred to as zero-power reference signal transmission. Although step S420 is described as being performed after step S415, this is only an example, and step S420 may be performed before step S415 according to the offset value.

The terminal acknowledges the non-transmission timing and the path loss (PL) measurement interval of the sub transceiver from the reference signal scheduling information received in step S410 (acknowledge). The terminal measures an uplink path loss based on the first reference signal or the first reference signal and the second reference signal received in the PL measurement section (S425). The PL measurement interval is a time interval designated for the UE to measure an uplink path loss value, and includes at least one non-transmission timing. As an example, the length of the PL measurement interval is determined according to the number of transmission and reception points constituting the cooperative set. For example, when the primary transmit / receive point and two secondary transmit / receive points form one cooperative set, the PL measurement interval may be three consecutive subframes as shown in FIG. 6.

Referring to FIG. 6, subframes #i to # (i + 2) are PL measurement intervals. When the primary transmit / receive point, the first sub-receive point and the second sub-receive point constitute one cooperative set, each transmit / receive point may have at least one unique non-transmission timing. For example, the non-transmission timing of the first subcarrier is subframes #i and # (i + 2), and the offset is 1. The non-transmission timing of the second subcarrier is subframes #i and # (i + 1), and the offset is 2. From the point of view of the terminal, in subframe #i, the terminal receives only the reference signal of the main transmission / reception point, and in subframe # (i + 1), the terminal receives the reference signals of the main transmission point and the first sub-reception point, In subframe # (i + 2), the terminal receives the reference signals of the main transceiver point and the second sub-receive point. In subframes other than the PL measurement interval, all transmission / reception points may transmit a reference signal.

As another example, the length of the PL measurement interval is determined depending on whether the reference signal transmission powers of the sub-transmission and reception points belonging to the cooperative set are the same or different. For example, if the reference signal transmission power of the sub transmission and reception points is the same, the PL measurement interval may be two subframes. Alternatively, when the reference signal transmission powers of the n sub transmission / reception points are different from each other, the PL measurement interval may be (n + 1) subframes.

Referring to FIG. 4 again, the terminal calculates uplink transmission power based on the measured uplink path loss value (S430).

The terminal transmits an uplink signal to the base station at the calculated uplink transmission power (S435).

Hereinafter, a method of measuring an uplink path loss value based on a PL measurement interval by the terminal will be described in more detail.

In a system in which a UE forms downlink and uplink with one base station as in the non-CoMP scheme, the UE determines uplink transmission power based on a path loss of a downlink reference signal. However, this assumes that a transmission point for transmitting a downlink signal to a terminal and a reception point for receiving an uplink signal from the terminal coincide with one base station. However, in the CoMP scheme, a downlink transmission point may not coincide with an uplink reception point. That is, a transmission point and a reception point may be separated for one terminal. In this case, the uplink power control method on the premise that the transmitting point and the receiving point are the same is not suitable. In addition, in a heterogeneous network in which a low power RRH and a macro base station coexist with different transmission powers, when both the low power RRH and the macro base station operate as reception points, it is ambiguous about which reception point to control the uplink power.

Since a plurality of uplink paths are formed between one terminal and a plurality of receiving points, the terminal should be able to obtain uplink path loss independently for each uplink path. If a plurality of receiving points all have different physical cell IDs as in the third scenario of the CoMP system, the CoMP terminal may distinguish each receiving point, and may identify an uplink path for each receiving point. On the other hand, according to the fourth scenario, since the transmitting and receiving points simultaneously transmit a reference signal based on the same physical cell ID to the terminal in a pathloss between different transmitting and receiving points, the terminal can distinguish the reference signals. none.

However, in the PL measurement interval in which the muting mode is allowed, the UE measures downlink path loss without receiving reference signals of at least one transmission / reception point every subframe. For example, referring to FIG. 6, in subframe #i, the UE measures downlink path loss without receiving reference signals of the second and third transmission and reception points. According to this method, the UE may obtain a downlink path loss value based on reference signals of different transmission / reception points in every subframe of the PL measurement period. By combining the downlink path loss values obtained for each subframe in this way, the UE can extract the downlink path loss values for each transmission / reception point individually. Furthermore, the terminal can obtain an uplink path loss value as a nonlinear average value of the downlink path loss values.

7 is a flowchart illustrating an operation of measuring, by the terminal, an uplink power loss value using a PL measurement interval according to an embodiment of the present invention. This is a case where the primary transmit / receive point and the first and second sub-receive points form a cooperative set, and the first and second sub-receive points transmit the reference signals to P _S1 and P _S2 at different powers. The muting period and the period in which the UE measures the RSRP may coincide, and the PL measurement interval has a different value depending on the size of the cooperative set.

Referring to FIG. 7, the terminal receives a reference signal every subframe in the PL measurement period (S700).

The i-th path loss value is calculated based on the reference signal received in subframe #i in which all sub-transmitting and receiving points are the muting mode (S705). The i th path loss value is calculated by the following equation.

Referring to Equation 2, L _i is the i-th path loss value for the downlink in dB unit. L _P is a path loss value of the reference signal of the primary transceiver. In subframe #i, since only the main transmission / reception point transmits a reference signal, L _i = L _P. The reference signal power of the reference signal is provided by an upper layer, and is an energy per resource element (EPRE) value of a downlink reference signal in dBm units. Reference Signal Received Power (RSRP) is defined as the linear average over the power contributions of all resource elements carrying a reference signal within the considered measurement frequency bandwidth. That is, when the main transceiver point informs the terminal of the transmission power value of the reference signal, the terminal may obtain the i-th path loss value by subtracting the measured value of the power of the reference signal actually received from the reference signal transmission power value.

Next, the UE calculates a (i + 1) th path loss value based on the reference signal received in the subframe # (i + 1) in which the second transmission / reception point is the muting mode (S710). In subframe # (i + 1), since the main transmission / reception point and the first sub transmission / reception point transmit the reference signal, the (i + 1) th path loss value is calculated by the following equation.

는 제(i+1) 경로 손실값이고, P_P는 주 송수신점의 기준신호 전송전력이며, P_S1은 제1 부 송수신점의 기준신호 전송전력이고, L_S1은 제1 부 송수신점의 기준신호에 대한 경로 손실값이다.

는 단말이 측정가능한 값이고, P_P, P_S1은 모두 단말이 이미 알고 있는 값이며, L_P는 수학식 2에서 구해진 값이다. 따라서, 단말은 제(i+1) 경로 손실값으로부터 L_S1를 다음의 수학식과 같이 구할 수 있다.Referring to Equation 3,

Is the (i + 1) path loss value, P _P is the reference signal transmit power of the primary transceiver point, P _S1 is the reference signal transmit power of the first secondary transceiver point, and L _S1 is the reference of the first secondary transceiver point The path loss value for the signal.

Is a value that can be measured by the terminal, P _P and P _S1 are values that the terminal already knows, and L _P is a value obtained from Equation 2. Accordingly, the terminal can obtain L _S1 from the (i + 1) th path loss value as in the following equation.

Next, the UE calculates a (i + 2) th path loss value based on the reference signal received in the subframe # (i + 2) in which the first sub transceiver point is the muting mode (S715). In subframe # (i + 2), since the main transmission / reception point and the second sub transmission / reception point transmit the reference signal, the (i + 2) th path loss value is calculated by the following equation.

는 제(i+2) 경로 손실값이고, P_S2는 제2 부 송수신점의 기준신호 전송전력이고, L_S2은 제2 부 송수신점의 기준신호에 대한 경로 손실값이다.

는 단말이 측정가능한 값이고, P_P, P_S2는 모두 단말이 이미 알고 있는 값이며, L_P는 수학식 2에서 구해진 값이다. 따라서, 단말은 제(i+2) 경로 손실값으로부터 L_S2를 다음의 수학식과 같이 구할 수 있다.Referring to Equation 5,

Is a (i + 2) th path loss value, P _S2 is a reference signal transmission power of the second sub transceiver station, and L _S2 is a path loss value of the reference signal of the second secondary transceiver point.

Is a value that can be measured by the terminal, P _P and P _S2 are values that the terminal already knows, and L _P is a value obtained from Equation 2. Accordingly, the UE can obtain L _S2 from the (i + 2) th path loss value as in the following equation.

The terminal determines a path loss value L _P for the reference signal of the primary transceiver point, a path loss value L _S1 for the reference signal of the first secondary transceiver point, and a path loss value L _S2 for the reference signal of the second secondary transceiver point. Based on the uplink path loss value PL _C is obtained by the following equation (S720).

Referring to Equation 7, the uplink path loss value PL _C is obtained as a non-linear average value of L _P , L _S1 , and L _S2 .

The terminal calculates uplink transmission power using the uplink path loss value PL _C (S725). In the case of the PUSCH, the uplink transmission power P _{PUSCH , C} (i) is scaled by the number of antennas for which at least one PUSCH transmission is performed and the number of antennas configured according to a transmission scheme. C is a serving cell to perform uplink transmission, and i is a number of a subframe in which uplink transmission is performed with power P _{PUSCH , C} (i). The adjusted total uplink transmission power is equally divided and allocated to the antennas performing at least one PUSCH transmission.

PUSCH transmission power is further divided into i) a case in which PUSCH and PUCCH are not transmitted simultaneously for any serving cell C and ii) a case in which both PUSCH and PUCCH are simultaneously transmitted.

In case of i), the UE calculates uplink transmit power P _{PUSCH , C} (i) defined by the following equation in subframe i for serving cell C.

In case of ii), the UE calculates uplink transmit power P _{PUSCH , C} (i) defined by the following equation in subframe i for serving cell C.

는 dB값을 선형으로 변환한 값이다. 한편,

는 P_PUCCH(i)를 선형으로 변환한 값이다. M_{PUSCH ,C}(i)는 서빙셀 C에 대한 서브프레임 i에서 PUSCH가 할당된 자원의 대역폭을 자원블록의 개수로 표현한 값이다. Referring to Equations 8 and 9, P _{CMAX , C} (i) is the maximum terminal outgoing power configured for the serving cell C,

Is the linear value of dB. Meanwhile,

Is a value obtained by linearly converting P _PUCCH (i). M _{PUSCH , C} (i) is a value representing the bandwidth of a resource allocated with a PUSCH in subframe i for the serving cell C in terms of the number of resource blocks.

P _{0 _ PUSCH , C} (i) is the sum of P _{0 _ NOMINAL _ PUSCH , C} (j) and P _{0 _ UE _ PUSCH , C} (j) for the serving cell C. For example, in case of semi-persistent grand PUSCH (re) transmission, it has a value of j = 0. On the other hand, in case of dynamic scheduled grand PUSCH (re) transmission, j = 1. If j = 0 or 1, it is signaled by a higher layer. And, in case of random access response grant PUSCH (re) transmission, j = 2. In addition, for random access response grant PUSCH (re) transmission, P _{0 _ UE _ PUSCH , C} (2) = 0 and P _{0 _ NOMINAL _ PUSCH , C} (2) = P _{0 _ PRE} + Δ _{PREAMBLE_Msg3} , where the parameter preambleInitialReceivedTargetPower (P _{0 _ PRE} ) and Δ _{PREAMBLE_Msg3} are signaled from higher layers.

If j = 0 or 1, one of the values of α _C ∈ {0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1} may be selected by the 3-bit parameter provided in the upper layer. When j = 2, α _C (j) = 1.

이다. 여기서, C는 코드블록의 개수이며, K_r은 코드블록의 크기이며, O_CQI는 CRC 비트수를 포함한 CQI/PMI 비트 개수이며, N_RE는 결정된 자원요소들의 개수이다. 즉, NRE=M_sc ^{PUSCH - initial}·N_symb ^{PUSCH - initial}이다. Δ _{TF , C} (i) = 10log ₁₀ ((2 ^{BPRE · Ks} −1) · β ^PUSCH _offset ), which is a parameter for reflecting the influence of the modulation and coding scheme (MCS). Here, K _S is a parameter provided as deltaMCS-Enabled in the upper layer for each serving cell C. In transmission mode 2, which is a mode for transmit diversity, K _S = 0. If only control information is transmitted through the PUSCH without UL-SCH data, BPRE = O _CQI / N _RE . In all other cases, BPRE =

to be. Here, C is the number of code blocks, K _r is the size of the code block, O _CQI is the number of CQI / PMI bits including the number of CRC bits, N _RE is the number of determined resource elements. That is, NRE = M _sc ^{PUSCH - initialN} _symb ^{PUSCH - initial} .

If only control information is transmitted without UL-SCH data through the PUSCH, β ^PUSCH _offset = β ^CQI _offset is set. Otherwise, it is always set to 1.

δ _{PUSCH , C} is a correction value. In addition, it is determined by referring to a TPC command present in DCI format 0 or 4 for serving cell c or a TPC command in DCI format 3 / 3A that is encoded and transmitted jointly with other terminals. In DCI format 3 / 3A, cyclic cyclic redundancy check (CRC) parity bits are scrambled with TPC-PUSCH-RNTI, so only terminals assigned the RNTI value can be checked. In this case, when an arbitrary terminal is configured with a plurality of serving cells, a different TPC-PUSCH-RNTI value may be allocated to each serving cell to distinguish each serving cell. Alternatively, a different TPC-PUSCH-RNTI value may be assigned to each transmit / receive point to distinguish between the transmit and receive points. f _c (i) indicates a PUSCH power control adjustment state for the serving cell C.

In FIG. 7, it is assumed that there are two secondary transmission / reception points. However, one secondary transmission / reception point may be one or two or more. In the case of one secondary transmission / reception point, the uplink path loss value PL _C can be calculated using only the i th path loss value and the (i + 1) th path loss value by the operation in Equations 3, 4, and 5, Calculations according to Equations 6 and 7 may be omitted.

The reference signal transmission powers of the sub transceivers belonging to the cooperative set may all be the same. In this case, all the sub transmission and reception points may operate in the muting mode at the same non-transmission timing as shown in FIG. 8. Every sub-transmission point has only one non-transmission timing in each muting period. That is, the non-transmission timing limit can be reduced. Since the offset 1 of all secondary transmission and reception points are equally designated, the UE can obtain an uplink path loss value without any separate signaling indicating the offset. In addition, the terminal may calculate the path loss for the reference signal of the main transmission and reception points and the path loss of the reference signal of the secondary transmission and reception points.

9 is a flowchart illustrating an operation of measuring an uplink power loss value by a terminal according to another embodiment of the present invention. This is a case where the sub transmission points all transmit the reference signal with the same power, and as shown in FIG. 8, non-transmission timing of all the sub transmission points coincides within the PL measurement interval.

9, the terminal receives a reference signal every subframe in the PL measurement interval (S900). The i-th path loss value is calculated based on the reference signal received in subframe #i in which all sub-transmitting and receiving points are the muting mode (S905). The i th path loss value is calculated by the following equation.

Referring to Equation 10, L _i is the i-th path loss value for the downlink in dB unit. L _P is a path loss value for the reference signal of the main transceiver point. In subframe #i, since only the main transmission / reception point transmits a reference signal, L _i = L _P. The reference signal power of the reference signal is provided by an upper layer, and is an energy per resource element (EPRE) value of a downlink reference signal in dBm units. RSRP is defined as the linear average over the power contributions of all resource elements carrying a reference signal within the measured frequency bandwidth under consideration. That is, when the main transceiver point informs the terminal of the transmission power value of the reference signal, the terminal may obtain the i-th path loss value by subtracting the measured value of the power of the reference signal actually received from the reference signal transmission power value.

Next, the terminal calculates a (i + 1) th path loss value based on the reference signal received in subframe # (i + 1) in which all transmission and reception points transmit the reference signal (S910). Since all transmission / reception points transmit reference signals in subframe # (i + 1), the (i + 1) th path loss value is calculated by the following equation.

는 제(i+1) 경로 손실값이고, P_P는 주 송수신점의 기준신호 전송전력이며, P_S는 모든 부 송수신점의 기준신호 전송전력이고, L_S1은 제1 부 송수신점의 기준신호에 대한 경로 손실값, L_S2은 제2 부 송수신점의 기준신호에 대한 경로 손실값이다.

는 단말이 측정가능한 값이고, P_P, P_S는 모두 단말이 이미 알고 있는 값이며, L_P는 수학식 10에서 구해진 값이다. 따라서, 단말은 제(i+1) 경로 손실값 L_S1와 L_S2의 비선형 합은 다음의 수학식과 같이 구할 수 있다. Referring to Equation 11,

Is the (i + 1) path loss value, P _P is the reference signal transmission power of the main transmission / reception point, P _S is the reference signal transmission power of all secondary transmission / reception points, and L _S1 is the reference signal of the first secondary transmission / reception point. The path loss value for, L _S2, is a path loss value for the reference signal of the second secondary transceiver point.

Is a value that can be measured by the terminal, P _P and P _S are values that the terminal already knows, and L _P is a value obtained from Equation 10. Accordingly, the terminal may obtain the nonlinear sum of the (i + 1) th path loss values L _S1 and L _S2 as shown in the following equation.

Therefore, the UE can obtain the uplink path loss value PL _C by the following equation (S915).

Referring to Equation 13, the uplink path loss value PL _C is obtained as a nonlinear average value of L _P , L _S1 , and L _S2 . The UE calculates uplink transmission power using the uplink path loss value PL _C (S920).

Hereinafter, the reference signal scheduling information will be described in more detail. The reference signal scheduling information includes at least one of non-Tx timing information indicating non-transmission timing of the secondary transceiver point, information on the reference signal transmission power of the secondary transceiver point, and information on the size of the cooperative set. Include.

As an example, the non-transmission timing information defines the non-transmission timing of the reference signal of each sub-reception point as a muting period and an offset. This is a case where the reference signal transmission power of each sub-reception point belonging to the cooperative set is different. Within the PL measurement interval, the offset indicates the point in time at which the reference signal of the sub transmission / reception point is transmitted. Conversely, the sub-transmitting and receiving points operate in the muting mode at timings other than offset within the PL measurement interval. Non-transmission timing information is defined individually for each sub-reception point included in the cooperative set. For example, non-transmission timing information may be defined as 4 bits as shown in the following table.

Non-Transmission Timing Information Bit Muting cycle (ms) offset 0000 5 mod (1, N) 0001 5 mod (2, N) 0010 5 mod (3, N) 0011 5 mod (4, N) 0100 10 mod (1, N) 0101 10 mod (2, N) 0110 10 mod (3, N) 0111 10 mod (4, N) 1000 20 mod (1, N) 1001 20 mod (2, N) 1010 20 mod (3, N) 1011 20 mod (4, N) 1100 40 mod (1, N) 1101 40 mod (2, N) 1110 40 mod (3, N) 1111 40 mod (4, N)

Referring to Table 2, N is the length (number of subframes) of the PL measurement interval. Alternatively, N may mean the size of the cooperative set, that is, the number of transmission and reception points included in the cooperative set. For example, when N = 4 and reference signal scheduling information of a specific CC is 1010, the muting period of the specific CC is 20ms, and an offset is mod (3,4) = 3ms. Therefore, the timing of transmitting the reference signal within the PL measurement point is 20 ms (muting period) + 3 ms (offset) = 23 ms. In other words, the specific transmission / reception point transmits a reference signal every 23ms, and the specific sub-reception point operates in the muting mode every 20ms, 21ms, and 22ms.

As another example, the non-transmission timing information defines the non-transmission timing of the reference signal of each sub-reception point as a muting period. This is the case where the reference signal transmission power of each sub-reception point belonging to the cooperative set is the same. Herein, the offset represents a time point at which the reference signal of the sub transmission / reception point is transmitted within the PL measurement section. Conversely, the sub-transmitting and receiving points operate in the muting mode at timings other than offset within the PL measurement interval. Non-transmission timing information is defined individually for each sub-reception point included in the cooperative set. For example, non-transmission timing information may be defined as 2 bits as shown in the following table.

Non-Transmission Timing Information Bit Muting cycle 00 5ms 01 10ms 10 20ms 11 40 ms

Referring to Table 3, for example, if reference signal scheduling information of a specific CC is 10, the muting period of the specific CC is 20 ms. Therefore, the specific sub-reception point operates in a muting mode every 20 ms.

As such, the reference signal scheduling information restricts or controls the transmission of the reference signal of each sub-transmission point belonging to the cooperative set, so that the terminal can selectively receive only the reference signal of a specific transmission / reception point during the PL measurement interval.

10 is a flowchart illustrating a method of controlling a transmission of a reference signal in a PL measurement section by a sub transceiver according to an example of the present invention.

Referring to FIG. 10, the secondary transmission / reception point receives reference signal scheduling from the primary transmission / reception point (S1000). The secondary transmission / reception point sets non-transmission timing according to the reference signal scheduling (S1005). Non-transmission timing is present in the PL measurement interval and is repeated periodically. Non-transmission timing is defined by a muting period and an offset, or by a muting period only.

The secondary transmission / reception point determines whether the current subframe is non-transmission timing of the PL measurement interval (S1010). If the current subframe is non-transmission timing, the secondary transmission and reception point operates in the muting mode (S1015). If the current subframe is not the non-transmission timing, the secondary transmission and reception point transmits a reference signal to the terminal (S1020). The reference signal includes a cell specific reference signal (CRS). The secondary transmission / reception point receives an uplink signal from the terminal (S1025). The uplink signal includes a physical channel such as a PUSCH or a PUCCH. The uplink signal is transmitted using the uplink transmission power determined by the terminal, and the uplink transmission power is determined based on the uplink path loss value determined based on the reference signal and the non-transmission timing.

11 is an example of a scenario of controlling uplink transmission power according to the present invention.

Referring to FIG. 11, a macro base station (eNodeB) 1100 serving as a main transmission / reception point and an RRH 1105 serving as a secondary transmission / reception point form one cooperative set and communicate with a UE UE 1110 in a CoMP scheme. This is a case where a transmission point for transmitting a downlink signal and a reception point for receiving an uplink signal are different. For example, a low power RRH may have a smaller transmission power than a macro base station, so that downlink coverage is small, but in the case of uplink, an RRH having a small uplink power loss may be selected.

The macro base station 1100 transmits a downlink signal to the terminal 1110, where a downlink path loss (PL_DL) occurs. The terminal 1110 transmits an uplink signal to the RRH 1105, where an uplink path loss (PL_UL) occurs. When the terminal uses the downlink path loss (PL_DL) to obtain the uplink path loss (PL_UL), since the path itself is different, the correct uplink path loss (PL_UL) is not accurate. Alternatively, in the cooperative multiple communication scenario 4, when the terminal receives the CRS from the RRH 1105 to obtain the uplink path loss (PL_UL), the terminal distinguishes two CRSs because the macro base station 1100 transmits the same CRS. Can not. Therefore, the uplink path loss PL_UL cannot be accurately calculated. However, according to the present invention, since the RRH 1105 operates in a muting mode at a specific non-transmission timing, an uplink path loss for the macro base station 1100 can be obtained at the non-transmission timing, and the non-transmission timing is determined. The uplink path loss PL_UL for the RRH 1105 may be obtained at the excluded time point.

12 is another example of a scenario of controlling uplink transmission power according to the present invention.

Referring to FIG. 12, a macro base station (eNodeB) 1200 that is a main transmission / reception point and an RRH 1205 that is a secondary transmission / reception point form one cooperative set, and communicate with a UE UE 1210 in a CoMP scheme.

The macro base station 1200 transmits a downlink signal to the terminal 1210, where a downlink path loss (PL_DL) occurs. The terminal 1210 transmits an uplink signal to the macro base station 1200 and the RRH 1205, where a first uplink path loss PL_UL1 and a second uplink path loss PL_UL2 occur, respectively.

In order for the terminal 1210 to obtain the first uplink path loss PL_UL1, it must first receive a CRS from the macro base station 1200. However, in the cooperative multiple communication scenario 4, since the RRH 1205 also transmits the same CRS to the terminal 1210, the terminal 1210 cannot obtain an accurate first uplink path loss PL_UL1. The same applies to the second uplink path loss PL_UL1. However, according to the present invention, since the RRH 1205 operates in the muting mode at a specific non-transmission timing, the first uplink path loss PL_UL1 for the macro base station 1200 can be obtained at the non-transmission timing. The second uplink path loss PL_UL2 for the RRH 1205 may be obtained at a time other than the non-transmission timing.

13 is another example of a scenario of controlling uplink transmission power according to the present invention.

Referring to FIG. 13, a macro base station (eNodeB) 1300 serving as a main transmission / reception point, and an RRH1 1305 and an RRH2 1310 serving as a secondary transmission / reception point form one cooperative set, and the UE (UE) 1315 may use a CoMP scheme. Perform communication.

The macro base station 1300, the RRH1 1305, and the RRH2 1310 transmit downlink signals to the terminal 1210, respectively, and each of the first downlink path loss (PL_DL1) and the second downlink path loss (PL_DL2) ), A third downlink path loss PL_DL3 occurs. The terminal 1210 transmits an uplink signal to the macro base station 1300, the RRH1 1305, and the RRH2 1310, and at this time, a first uplink path loss (PL_UL1) and a second uplink path loss (for each). PL_UL2) and a third uplink path loss PL_UL3.

According to the present invention, the RRH1 1305 and the RRH2 1310 operate in a muting mode at the first non-transmission timing, the RRH2 1310 operate in a muting mode at the second non-transmission timing, and the RRH1 1305 operates in the muting mode. 3 Operates in muting mode at non-transmission timing. The UE 1315 may obtain the first uplink path loss PL_UL1 for the macro base station 1300 at the first non-transmission timing, and the second uplink path loss for the RRH1 1305 at the second non-transmission timing. (PL_UL2) can be obtained, and the third uplink path loss (PL_UL3) for the RRH2 1310 can be obtained at the third non-transmission timing.

14 is a block diagram illustrating a terminal and a transmission and reception point according to an embodiment of the present invention.

Referring to FIG. 14, the terminal 1400 includes a terminal RF unit 1405 and a terminal processor 1410. The terminal processor 1410 includes a terminal message processor 1411 and a transmission power controller 1412.

The terminal RF unit 1405 receives reference signal (RS) scheduling information from the main transmission / reception point 1480, receives a reference signal from the transmission / reception point 1450, and transmits an uplink signal to the transmission / reception point 1450. The transceiver point 1450 may be a secondary transceiver point.

The terminal message processor 1411 analyzes the information included in the RS scheduling information, obtains non-transmission timing information of the transmission / reception point 1450, and transmits the non-transmission timing information to the transmission power controller.

The transmit power controller 1412 may obtain an uplink path loss value according to the operation flowchart of FIG. 7 or 9. For example, the transmission power control unit 1412 may include a first downlink path loss value generated at the non-transmission timing of the transmission / reception point 1450 and a second downlink path loss value generated at the transmission timing of the transmission / reception point 1450. Obtain The transmit power controller 1412 estimates a first uplink path loss value from a first downlink path loss value, a reference signal transmit power value of the transceiver point 1450, the first uplink path loss value, and A second uplink path loss value is obtained from the first downlink path loss value. The transmission power controller 1412 determines a final uplink path loss value by taking a non-linear average value of the first and second uplink path loss values.

The transmit power controller 1412 calculates the uplink transmit power by substituting the final uplink path loss value into an equation for obtaining the uplink transmit power value as shown in Equation (8).

The terminal RF unit 1405 transmits an uplink signal to the transceiver point 1450 using the uplink transmission power obtained by the transmission power control unit 1412.

The transceiver point 1450 includes a transceiver point RF unit 1455 and a transceiver point processor 1460. The transmit / receive point processor 1460 includes a transmit / receive point message processor 1462 and an RS transmission controller 1462.

The transceiver point RF unit 1455 transmits a reference signal to the terminal 1400 based on the non-transmission timing. The transceiver point RF unit 1455 receives an uplink signal transmitted at a specific level of transmission power from the terminal 1400, and receives RS scheduling information from the primary transceiver point 1480.

The transceiver message processor 1541 may analyze the received uplink signal or RS scheduling information, perform an operation according to the uplink signal, or extract non-transmission timing information unique to the transceiver point 1450 to generate an RS transmission controller ( 1462) or a higher layer message.

The RS transmission control unit 1462 controls the transmission of the reference signal of the transmission / reception point 1450. For example, the RS transmission controller 1462 controls the transmission / reception point 1450 to operate in a muting mode at non-transmission timing. The muting mode is a mode in which the RS transmission control unit 1462 sets the reference signal to zero power. The RS transmission control unit 1462 controls the transmission / reception point RF unit 1455 to transmit the reference signal at other times except for the non-transmission timing, and controls the transmission / reception point RF unit 1455 not to transmit the reference signal at non-transmission timing. do.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (18)

In the control method of the uplink transmission power for the terminal performed by the terminal,
Calculating, by the terminal, an uplink path loss value in a designated PL measurement interval to measure an uplink pathloss (PL) value;
Calculating uplink transmission power based on the uplink path loss value; And
Transmitting an uplink signal according to the uplink transmission power,
The PL measurement interval includes a plurality of subframes,
The PL measurement interval includes a non-transmission timing at which a secondary transmit / receive point operates in a muting mode.
The muting mode is a control method for uplink transmission power, characterized in that the sub-transmission point is a mode for setting a cell-specific reference signal to zero-power (zero-power). The method of claim 1,
The terminal receives the cell specific reference signal from the sub-transmitting and receiving point at the remaining time except for the non-transmission timing within the PL measurement interval, the uplink transmission power control method. The method of claim 2,
And receiving information regarding the non-transmission timing from a primary transmission / reception point. The method of claim 3, wherein
The primary transmission point and the secondary transmission point and the transmission and reception point characterized in that the cooperative set by cooperative multiple point transmission and reception (CoMP), uplink transmission power control method. The method of claim 4, wherein
The main transmission and reception point is a macro base station (macro eNB), the secondary transmission and reception point characterized in that the remote radio head (remote radio head (RRH)), control method of uplink transmission power. The method of claim 4, wherein
And the length of the PL measurement interval is equal to the size of the cooperative set. The method of claim 3, wherein
The non-transmission timing information includes transmission power information of the cell measurement reference signal and a period in which the cell measurement reference signal becomes zero power. The method of claim 3, wherein
The non-transmission timing information may include transmission power information of the cell measurement reference signal, a period at which the cell measurement reference signal becomes zero power, and an offset indicating a time point at which the cell measurement reference signal does not become zero power within the period. and an offset (offset). The method of claim 1, wherein the calculating of the uplink path loss value comprises:
Calculating a first downlink path loss value in a first subframe of the plurality of subframes;
Calculating a second downlink path loss value in a second subframe of the plurality of subframes; And
Calculating an uplink path loss value of a transmission / reception point for transmitting a cell measurement reference signal in the second subframe based on the first downlink path loss value and the second downlink path loss value. Characterized in that the uplink transmission power control method. The method of claim 9, wherein the uplink path loss value,
And calculating a non-linear average of uplink path loss values of sub-transmitting and receiving points included in the cooperative set. In the control method of uplink transmission power for a terminal performed by a remote radio head,
The terminal operating in a muting mode at a non-transmission timing included in a PL measurement interval used to measure an uplink pathloss (PL) value;
Transmitting a cell specific reference signal to the terminal at a point other than the non-transmission timing in the PL measurement section; And
And receiving from the terminal an uplink signal transmitted with an uplink transmission power based on an uplink path loss value calculated in the PL measurement interval. The method of claim 11,
The muting mode, characterized in that the remote radio head is a mode for setting the cell-specific reference signal to zero power, control method of uplink transmission power. The method of claim 11, wherein the information about the non-transmission timing,
The transmission power information of the cell measurement reference signal and a period in which the cell measurement reference signal becomes zero power, or indicate a time point at which the cell measurement reference signal does not become zero power within the transmission power information, the period, and the period. The uplink transmission power control method, characterized in that it comprises an offset. The method of claim 11,
Different remote radio heads are assigned different non-transmission timing within the PL measurement interval, the method of controlling uplink transmission power. 15. The method of claim 14,
And different remote radio heads transmit cell-specific reference signals at different powers. The method of claim 11,
And different remote radio heads are assigned the same non-transmission timing within the PL measurement interval. 17. The method of claim 16,
And the different remote radio heads transmit cell specific reference signals with the same power. The method of claim 11, wherein the information about the non-transmission timing,
Method of controlling uplink transmission power, characterized in that the radio resource control (RCC) message transmitted from the macro base station to the terminal.

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