KR102166255B1 - Apparatus and method for controlling uplink transmission power in wireless communication system - Google Patents

Abstract

It provides a terminal that controls uplink transmission power in a wireless communication system supporting dual connectivity. The UE receives an RF unit for receiving a radio resource control message for configuring the dual connection from a first base station configuring the dual connection, a first transmission power for a first physical channel to be transmitted to the first base station, and the A processor that calculates a second transmission power for a second physical channel to be transmitted to a second base station constituting a dual connection, wherein the first transmission power is scaled according to priority or adjusted by power filling, and the first physical channel At least one of the channel and the second physical channel is a physical random access channel (PRACH), and includes a memory for storing a power control parameter used to calculate the first transmission power and the second transmission power.

Description

Uplink transmission power control device and method in wireless communication system {APPARATUS AND METHOD FOR CONTROLLING UPLINK TRANSMISSION POWER IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to wireless communication, and more particularly, to a terminal and method for controlling uplink power of a terminal in a situation in which dual connectivity is configured.

In a wireless communication system, a terminal may perform wireless communication through two or more of base stations constituting at least one serving cell. This is called dual connectivity. In other words, the dual connection is an operation in which at least two different network points and a terminal configured in an RRC connected state consume radio resources provided by the network points. can do. Here, at least two or more different network points may be a plurality of base stations physically or logically separated, one of which is a master base station (MeNB: Master eNB), and the remaining base stations may be a secondary base station (SeNB: Secondary eNB). have.

In a situation in which the terminals are distributed near or far from the base station, when the terminal transmits an uplink signal, the strength of the signal received by the base station may differ according to the location of the terminal. For example, assuming that all terminals transmit signals with the same power, a signal transmitted by a terminal located near the base station is received much larger than a signal transmitted by a terminal located far away. Therefore, there is no problem in making a call to a terminal located nearby, but a terminal located far away suffers a relatively very large interference. A technology for solving this problem is transmission power control (TPC). The TPC command is a signaling transmitted to the terminal in order to perform power control of a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH) in the base station. Due to the TPC, the base station can receive an uplink signal with a uniform power intensity. The TPC command may be applied to a specific subframe.

When the first base station and the second base station configure dual connectivity for the terminal, when the terminal transmits PUSCH or PUCCH to the first base station, the second base station transmits a physical random access channel (PRACH), or A power filling technique can be applied. In this case, PUSCH or PUCCH transmission is affected by PRACH transmission or power filling, and the UE may eventually perform PUSCH or PUCCH transmission to the first base station with less or more than the actual calculated transmission power (ie, uplink Transmit power fluctuation occurs). At this time, the network may erroneously recognize the fluctuation as a change in interference and may issue an incorrect TPC command. Therefore, there is a need for a method to avoid such erroneous TPC commands.

An object of the present invention is to provide a terminal that controls uplink transmission power of a terminal in a dual connection configuration.

Another technical problem of the present invention is to provide a method of controlling uplink transmission power of a terminal in a situation in which dual connectivity is configured.

According to an aspect of the present invention, a method for controlling uplink transmission power by a terminal in a wireless communication system supporting dual connectivity is provided. The method includes receiving a radio resource control (RRC) message for configuration of the dual connection from a first base station configuring the dual connection, a first physical channel to be transmitted to the first base station Calculating a first transmission power for and a second transmission power for a second physical channel to be transmitted to a second base station constituting the dual connection, wherein the first transmission power is scaled according to priority ) Adjusted by power filling, and at least one of the first physical channel and the second physical channel is a physical random access channel (PRACH); Transmitting the first physical channel and the second physical channel to the first base station and the second base station at the same time, respectively, receiving a transmit power control (TPC) command from the first base station And, different from the TPC command, performing uplink power control for the first physical channel.

Here, the first physical channel is transmitted on a serving cell c, and performing uplink power control may include maintaining a current power control control state of the first physical channel for the serving cell c as it is. have.

In addition, the first physical channel is transmitted on a serving cell c, and performing uplink power control includes correcting a value indicated by the TPC command based on at least one of the scaling and the power filling, and the It may further include reflecting the correction to the current power control adjustment state of the first physical channel for the serving cell c.

Meanwhile, the first physical channel is at least one of a physical uplink common channel (PUSCH) and a physical uplink control channel (PUCCH), and the second physical channel is a PRACH, or both the first physical channel and the second physical channel It can be PRACH.

In addition, one of the first base station and the second base station may be a master base station, and the other may be a secondary base station.

According to another aspect of the present invention, a terminal for controlling uplink transmission power in a wireless communication system supporting dual connectivity is provided. The terminal receives a radio resource control (RRC) message for the configuration of the dual connection from a first base station configuring the dual connection, a radio frequency (RF) unit, a first physical channel to be transmitted to the first base station A processor for calculating a first transmission power and a second transmission power for a second physical channel to be transmitted to a second base station constituting the dual connection, wherein the first transmission power is scaled according to priority or power Adjusted by power filling, at least one of the first physical channel and the second physical channel is a physical random access channel (PRACH), and is used to calculate the first and second transmission powers And a memory for storing the power control parameters. The RF unit simultaneously transmits the first physical channel and the second physical channel to the first base station and the second base station, respectively, and transmits a transmit power control (TPC) command from the first base station. And the processor may perform uplink power control for the first physical channel differently from the TPC command.

Here, the RF unit may transmit the first physical channel on a serving cell c, and the processor may maintain a current power control control state of the first physical channel for the serving cell c as it is.

In addition, the RF unit transmits the first physical channel on a serving cell c, and the processor corrects a value indicated by the TPC command based on at least one of the scaling and the power filling, and performs the correction. It may be reflected in the current power control adjustment state of the first physical channel for cell c.

Meanwhile, the first physical channel is at least one of a physical uplink common channel (PUSCH) and a physical uplink control channel (PUCCH), and the second physical channel is a PRACH, or both the first physical channel and the second physical channel It can be PRACH.

In addition, one of the first base station and the second base station may be a master base station, and the other may be a secondary base station.

According to the present embodiment, the UE can adaptively correct or maintain uplink power control for a TPC command transmitted in error by a network due to PRACH transmission or power filling in a dual connection.

1 shows a wireless communication system to which an embodiment of the present invention can be applied.
2 shows an example of a dual connection to which an embodiment of the present invention can be applied.
3 shows an example of a hierarchical structure each of two base stations dually connected to a terminal.
4 is a flowchart illustrating a method of performing uplink power control according to an example of the present invention.
5 is a flowchart illustrating a method of performing uplink power control according to another example of the present invention.
6 is a flowchart illustrating a method of performing uplink power control according to another example of the present invention.
7 is a flowchart illustrating a method of performing uplink power control according to another example of the present invention.
8 is a block diagram showing a wireless communication system in which an embodiment of the present invention is implemented.

Hereinafter, in the present specification, contents related to the present invention will be described in detail through exemplary drawings and embodiments along with the contents of the present invention. In adding reference numerals to constituent elements in each drawing, it should be noted that the same constituent elements are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing an embodiment of the present specification, if it is determined that a detailed description of a related known configuration or function may obscure the subject matter of the present specification, a detailed description thereof will be omitted.

In addition, this specification describes a wireless communication network, and the work performed in the wireless communication network is performed in the process of controlling the network and transmitting data in a system (for example, a base station) that governs the wireless communication network, or The work can be done at a terminal coupled to the network.

1 shows a wireless communication system to which an embodiment of the present invention can be applied.

Referring to FIG. 1, a wireless communication system 10 is widely deployed to provide various communication services such as voice and packet data. The wireless communication system 10 includes at least one base station 11 (evolved NodeB, eNB). Each base station 11 provides a communication service for a specific cell (15a, 15b, 15c). Cells can be further divided into multiple areas (referred to as sectors).

Terminal (User Equipment: UE, 12) can be fixed or mobile, MS (mobile station), MT (mobile terminal), UT (user terminal), SS (subscriber station), wireless device (wireless device), PDA (personal digital assistant), wireless modem (wireless modem), handheld device (handheld device) can be referred to as other terms. The base station 11 may be referred to as a base station (BS), a base transceiver system (BTS), an access point, a femto base station, a home nodeB, a relay, and the like. The cell should be interpreted in a comprehensive meaning indicating a partial area covered by the base station 11, and is meant to encompass all of various coverage areas such as megacells, macrocells, small cells, microcells, picocells, and femtocells. The base station 11 may provide at least one cell to the terminal. The cell may mean a geographic area in which the base station 11 provides a communication service, or a specific frequency band. A cell may mean a downlink frequency resource and an uplink frequency resource. Alternatively, the cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource.

Downlink (DL) refers to communication from the base station 11 to the terminal 12, and uplink (UL) refers to communication from the terminal 12 to the base station 11. In downlink, the transmitter may be a part of the base station 11 and the receiver may be a part of the terminal 12. In the uplink, the transmitter may be a part of the terminal 12 and the receiver may be a part of the base station 11.

Wireless communication systems include Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA (SC-FDMA), and OFDM-FDMA. , OFDM-TDMA, OFDM-CDMA, such as various multiple access techniques can be used.

For uplink transmission and downlink transmission, a Time Division Duplex (TDD) scheme transmitted using different times may be used, or a Frequency Division Duplex (FDD) scheme transmitted using different frequencies may be used.

Meanwhile, the radio interface between the terminal 12 and the base station 11 is referred to as a “Uu interface”. The layers of the radio interface protocol between the terminal 12 and the network are the first layer (L1) defined in the 3rd Generation Partnership Project (3GPP) series of wireless communication systems (UMTS, LTE, LTE-Advanced, etc.), 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, and the radio resource control (RRC) layer located in the third layer exchanges RRC messages to the terminal Control radio resources between (12) and the network.

The following physical control channels are used in the physical layer. The PDCCH (physical downlink control channel) informs the UE of resource allocation of a paging channel (PCH) and a downlink shared channel (DL-SCH) and hybrid automatic repeat request (HARQ) information related to the DL-SCH. The PDCCH may carry an UL grant that informs the UE of resource allocation for uplink transmission. The DL-SCH is mapped to the PDSCH (physical downlink shared channel). The PCFICH (physical control format indicator channel) informs the UE of the number of OFDM symbols used for PDCCHs, and is transmitted every subframe. A PHICH (physical hybrid ARQ indicator channel) is a downlink channel and carries a HARQ ACK/NACK (Hybrid ARQ Acknowledgement/Non-acknowledgement) signal that is a response of an uplink transmission. The PUCCH (Physical uplink control channel) carries uplink control information such as a HARQ ACK/NACK signal for downlink transmission, a scheduling request, and CQI. A physical uplink shared channel (PUSCH) carries an uplink shared channel (UL-SCH). A physical random access channel (PRACH) carries a random access preamble.

The RRC layer is in charge of controlling logical channels, transport channels and physical channels in relation to configuration, re-configuration and release of RBs. A radio bearer (RB) refers to a logical path provided by a first layer (PHY layer) and a second layer (MAC layer, RLC layer, PDCP layer) for data transmission between a terminal and a network. Configuring the RB means a process of defining characteristics of a radio protocol layer and channel to provide a specific service, and setting specific parameters and operation methods for each. RB can be classified into SRB (Signaling RB) and DRB (Data RB). SRB is used as a path for transmitting RRC messages and non-access stratum (NAS) messages in the control plane, and DRB is used as a path for transmitting user data in the user plane.

RB refers to two things: data RB (Data Radio Bearer) and signaling RB (SRB: Signaling Radio Bearer), but RB without distinction in the present invention is a DRB provided in the Uu interface to support the user's service. . Therefore, RB expressed without distinction is distinguished from SRB. RB is a path through which data of the user plane is transmitted, and SRB is a path through which data of a control plane such as an RRC layer and a NAS control message is transmitted. One-to-one mapping is established between RB and E-RAB and EPS bearers. The base station maps the DRB and the S1 bearer to one-to-one to create a DRB that binds both uplink and downlink, and stores them. In order to create an S1 bearer and an S5/S8 bearer that binds both uplink and downlink, the S-GW maps the S1 bearer and the S5/S8 bearer 1:1 and stores them.

The NAS (Non-Access Stratum) layer located above the RRC layer performs functions such as connection management (Session Management) and mobility management (Mobility Management). When there is an RRC connection between the RRC layer of the terminal and the RRC layer of the E-UTRAN, the terminal is in an RRC connected state, otherwise, it is in an RRC idle state. do.

The uplink transmission power of the terminal on the serving cell does not exceed the maximum terminal output power (P _CMAX ) configured in the serving cell. The _range of P _CMAX is as follows:

P _CMAX is determined by the maximum power P _EMAX, the definition of P and P _{CMAX CMAX _L _H} hence are the following mathematical expression.

Here, P _EMAX is the maximum power allowed or usable when the UE transmits uplink in the corresponding cell, and may be signaled by an upper layer (eg, an RRC signal). For example, P _EMAX may be a value specified for each cell by P-Max included in RRC signaling, and may have, for example, a value of -30db to 33dB. P _EMAX is used to calculate Srxlev, which is a cell selection Rx level value, and is also used to limit the configured maximum terminal output power (P _CMAX ). If P-Max is not included in the RRC signaling, the UE applies the maximum power according to UE capability.

P _POWERCLASS is the maximum output power determined according to the class of the terminal. MPR (maximum power reduction) is a power reduction value set in a range that satisfies a set requirement condition in consideration of a corresponding band and modulation. The A-MPR is a value set by the terminal within the range indicated by the base station. P-MPR is the maximum output power attenuation allowed in consideration of the case of operating systems other than LTE such as 1xRTT. ΔT _C is a fixed power offset value and is a function of the transmission bandwidth (transmission BW) for the component carrier.

On the other hand, the base station may be classified into a macro base station, a pico base station, a femto base station, etc. according to coverage.

The macro base station is a commonly used base station and has a wider coverage compared to a pico base station or a femto base station. Therefore, the macro base station transmits signals with relatively strong power.

The pico base station is a base station installed for a hotspot or a coverage hole and has a small coverage. The pico base station transmits signals with relatively small power.

A cell provided by a macro base station is called a macro cell, and a frequency supporting the macro cell is called a macro cell layer. The macro cell provides a terminal with a relatively reliable connection than a cell provided by a pico base station or a femto base station.

The cell provided by the pico base station is called a pico cell, and is called a small cell in the sense that the coverage of the cell provided by the pico base station is small. In addition, the pico base station is also referred to as a small base station or a small cell base station. The small cell provides a relatively non-reliable connection to the terminal compared to the macro cell.

In a network environment in which macro cells and small cells are mixed, macro cells and small cells enable more efficient wireless operation by distributing traffic or transmitting traffic of different QoS.

2 shows an example of a dual connection to which an embodiment of the present invention can be applied. Dual connectivity refers to the simultaneous use of a macro cell and a small cell in a network environment in which a macro base station and a small base station coexist with each other. In other words, the dual connection is an operation in which at least two different network points and a terminal configured in an RRC connected state consume radio resources provided by the network points. can do. Here, at least two or more different network points may be a plurality of base stations physically or logically separated. According to dual connectivity, efficient network configuration and terminal transmission and reception are possible, and traffic distribution and transmission efficiency can be improved.

Referring to FIG. 2, the UE may perform simultaneous UL transmission or simultaneous DL reception from a macro base station (M) and a small base station (S). Although the macro base station (M) and the small base station (S) are backhaul connected, a delay of 25 to 65 ms may occur in case of an abnormal backhaul.

In dual connectivity, each base station transmits downlink data and receives uplink data through a bearer configured for one terminal. In this case, one bearer may be configured through one base station, or may be configured through two or more different base stations.

In dual connectivity, at least one serving cell may be configured in each base station, and each serving cell may be operated in an activated or deactivated state. For example, the macro base station (M) may provide (or configure) two serving cells, and the small base station (S) may provide (or configure) three serving cells. At this time, a primary serving cell (PCell: Primary (serving) Cell) configurable in a carrier aggregation (CA) method may be configured in the macro base station, and a secondary (serving) cell (SCell) in the small base station Only can be constructed. Here, carrier aggregation is a technology for efficiently using fragmented small bands, and one base station is physically continuous or non-continuous in the frequency domain, or serving a plurality of component carriers. The purpose is to combine cells to produce the same effect as using a logically large band.

In a situation in which dual connectivity is configured in a terminal, serving cells provided by each base station to the terminal are grouped and referred to as a cell group. Hereinafter, the macro base station (M) is referred to as a base station serving as a master, and is referred to as a master base station (MeNB), and a group of serving cells provided by the master base station to the terminal is referred to as a master cell group (MCG). It will be referred to as this. In addition, hereinafter, the base station serving as the small base station (S) is referred to as a secondary base station (SeNB), and the group of serving cells provided by the secondary base station to the terminal is referred to as a secondary cell group (SCG). It will be referred to as That is, several serving cells may exist in one eNB.

In the secondary cell group, a secondary primary serving cell (sPcell, Secondary Primary Cell) having a PUCCH may be configured. The corresponding cell refers to a cell that plays a similar role to the main non-cell of the master cell group. A contention-based random access procedure as well as a contention-based random access procedure may be performed through the corresponding cell.

An Xn interface may be defined between the master base station and the secondary base station, and the Xn interface may be provided with various facilities such as fiber or DSL, cable, and wireless backhaul. The following Tables 1 and 2 are examples of backhaul performance when designing the Xn interface for each facility, and Table 1 is for non-ideal backhaul and Table 2 is for ideal backhaul.

Backhaul equipment Delay (one-way) Throughput Fiber Access 1 10-30ms 10M-10Gbps Fiber Access 2 5-10ms 100-1000Mbps Fiber Access 3 2-5ms 50M-10Gbps DSL　Access 15-60ms 10-100 Mbps Cable 25-35ms 10-100 Mbps Wireless Backhaul 5-35ms 10Mbps-100Mbps, Gbos range supported

Backhaul equipment Delay (one-way) Throughput Fiber Access 4 2.5us or less Up to 10 Gbps

3 shows an example of a hierarchical structure each of two base stations dually connected to a terminal.

Referring to FIG. 3, a master base station and a secondary base station may individually have schedulers such as a PHY layer, a MAC layer, an RLC layer, and a PDCP layer, and uplink transmission scheduling for each base station is individually performed by the corresponding base station. The master base station and the secondary base station have a structure in which at least the PHY layer and the MAC layer are independently configured. Alternatively, the PDCP layer and the RLC layer may be located at each base station or only at the master base station.

Due to the delay time of the non-ideal backhaul connection between the master base station and the secondary base station, the master base station and the secondary base station cannot share their scheduler information with each other. At this time, the master base station and the secondary base station cannot know the counterpart's uplink grant information.

The base station determines an uplink grant to maximize transmission efficiency. For example, the base station may allocate an uplink grant in consideration of the sum of power headroom (PH) information (ie, total power surplus information) for all base stations transmitted by the terminal. If an uplink grant having a size equal to or larger than the configured maximum terminal output power is allocated, scaling down may occur in the uplink transmission power of the terminal. Here, the scaling of power refers to attenuating the transmission power by a certain ratio in order to allocate power so as not to exceed the total transmission power of the terminal. Power scaling can be expressed in various ways, such as power control, power scaling, and power control.

On the other hand, when the terminal is capable of uplink transmission to a plurality of cells (eg, a CA situation), the maximum terminal output power (P _CMAX ) configured in consideration of the plurality of cells is determined as in the following equation, unlike equation (1).

Here, the definition of P _{CMAX _L_ CA} and P _{CMAX _H_ CA} are as following mathematical expression, unlike the equation (2).

Here, p _{EMAX, c} is the linear value of _{P EMAX, c, P EMAX,} c corresponds to the maximum power allowed in the mobile station performs uplink transmission in the cell. P _{EMAX ,c} is given by P-Max for the serving cell c. P-Max is a fixed maximum power value for each serving cell, and may be a cell-specific value transmitted to the UE by RRC signaling. P-Max can have a value from -30dB to 30dB.

Meanwhile, the setting of the transmission power of the terminal for PUSCH transmission may be defined as follows.

If the UE transmits the PUSCH for the serving cell c, not simultaneously with the PUCCH (If the UE trnasmits PUSCH without a simultaneous PUCCH for the serving cell c), then PUSCH transmission in subframe i for the serving cell c The UE transmission power for P _{PUSCH ,c} (i) is given by Equation 7 below.

If the UE transmits the PUSCH simultaneously with the PUCCH for the serving cell c, P _{PUSCH ,c} (i) _, which is the UE transmission power for PUSCH transmission in subframe i for the serving cell c, is given as Equation 8 below. .

If the UE is not transmitting PUSCH for the accumulation of TPC commands received with DCI format 3/3A for PUSCH for serving cell c, if the UE is not transmitting PUSCH for the serving cell c, for the accumulation of TPC command received with DCI format 3/3A for PUSCH), P _{PUSCH , c} (i), which is UE transmission power for PUSCH transmission in subframe i for the serving cell c, is as shown in Equation 9 below. The terminal assumes that it is computed by.

는 P_{CMAX ,c}(i)의 선형 값이다.Here, P _{CMAX ,c} (i) is the maximum terminal transmission power configured for the serving cell c,

Is the linear value of P _{CMAX ,c} (i).

는 P_PUCCH(i)의 선형 값이다. P_PUCCH(i)는 서브프레임 i에서의 PUCCH 전송 전력이다.

Is the linear value of P _PUCCH (i). P _PUCCH (i) is the PUCCH transmission power in subframe i.

In addition, M _{PUSCH ,c} (i) is a value expressed by the number of RBs of the bandwidth of the resource allocated with the PUSCH in subframe i for the serving cell c.

In addition, P _{O _ PUSCH ,c} (j) is the sum of P _{O _ NOMINAL _ PUSCH ,c} (j) and P _{O _ UE _ PUSCH ,c} (j) for the serving cell c, and the j value from the upper layer is Available as 0 or 1. In the case of semi-persistent grant PUSCH transmission (or retransmission), j is 0, whereas in the case of dynamic scheduled grant PUSCH transmission (or retransmission), j is 1, and random access response grant PUSCH transmission In the case of (or retransmission), j is 2. In the case where the random access response grant PUSCH transmission (or retransmission) P _{O _ UE _} and _{PUSCH, c (2) = 0} , P O_NOMINAL_PUSCH, c (2) is the sum of the P _{O _ PRE} and Δ _{PREAMBLE _ Msg3,} Here, the parameters P _{O_PRE} (preambleInitialReceivedTargetPower) and Δ _{PREAMBLE _ Msg3} are signaled from the upper layer.

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

PL _c is a dB value of an expected downlink path loss (PL, or path attenuation) value for the serving cell c calculated by the terminal, and can be obtained from "referenceSignalPower-higher layer filtered RSRP". Here, referenceSignalPower is a value provided by an upper layer and is a unit of dBm of an EPRE (Energy Per Resource Element) value of a downlink reference signal. Reference Signal Received Power (RSRP) is a reception power value of a reference signal for a reference serving cell. The serving cell selected as the reference serving cell, referenceSignalPower used for calculating the PL _c, and higher layer filtered RSRP are determined by the higher layer parameter pathlossReferenceLinking. Here, the reference serving cell configured by the pathlossReferenceLinking may be a primary serving cell or a DL SCC of a secondary serving cell corresponding to a UL CC and SIB2.

이다. 여기서, K_s는 각 서빙셀 c에 대하여 상위계층에서 deltaMCS-Enabled으로 제공되는 파라미터이며 1.25 또는 0이며, 특히, 전송 다이버시티(Transmit diversity)를 위한 모드인 전송 모드2(transmission mode 2)인 경우 K_s는 언제나 0이다. 또한, UL-SCH 데이터 없이 PUSCH를 통해 제어정보만이 전송되는 경우 BPRE=O_CQI/N_RE이고, 그 밖의 경우

인데, C는 코드블록의 개수이며, K_r은 코드블록의 크기이며, O_CQI는 CRC 비트수를 포함한 CQI/PMI 비트 개수이며, N_RE는 결정된 자원 요소(Resource Element)들의 개수(즉,

)이다. M^{PUSCH-initial} _sc는 동일한 전송 블록에 대한 초기(initial) PUSCH 전송을 위한 부반송파의 수이고, N^{PUSCH - initial} _Symb는 동일한 전송 블록에 대한 초기(initial) PUSCH 전송을 위한 서브프레임당 SC-FDMA 심벌의 수이다. 또한, 만일 PUSCH를 통해 UL-SCH 데이터 없이 제어정보만이 전송되는 경우 β^PUSCH _offset=β^CQI _offset로 설정하고, 그 이외의 경우는 β^PUSCH _offset는 항상 1로 설정한다.In addition, Δ _{TF ,c} (i) is a parameter to reflect the influence of the MCS (modulation coding scheme), and its value is

to be. Here, K _s is a parameter provided as deltaMCS-Enabled in the upper layer for each serving cell c, and is 1.25 or 0. In particular, in the case of transmission mode 2, which is a mode for transmit diversity K _s is always zero. In addition, when only control information is transmitted through PUSCH without UL-SCH data, BPRE = O _CQI /N _RE , in other cases

Where 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, and N _RE is the number of determined resource elements (i.e.,

)to be. M ^{PUSCH-initial} _sc is the number of subcarriers for initial PUSCH transmission for the same transport block, and N ^{PUSCH - initial} _Symb is an SC-FDMA symbol per subframe for initial PUSCH transmission for the same transport block. Is the number of In addition, if only control information is transmitted without UL-SCH data through PUSCH, β ^PUSCH _offset = β ^CQI _offset is set, and in other cases, β ^PUSCH _offset is always set to 1.

Further, δ _{PUSCH ,c} is a correction value, and may also be referred to as a "TPC command". δ _{PUSCH ,c} is included in the PDCCH/EPDCCH having DCI format 0 or 4 (0/4) for the serving cell c, or jointly coded with other TPC commands in the PDCCH having DCI format 3/3A. coded). In the DCI format 3/3A, since CRC parity bits are scrambled as TPC-PUSCH-RNTI, only terminals to which the RNTI value is assigned can check. The following Table 3 shows the mapping of the TPC command field in DCI format 0/3/4 to the accumulated or absolute TPC value, and Table 4 shows the mapping of the TPC command field in DCI format 3A to the absolute TPC value. Represents.

The PUSCH power control adjustment state for the current serving cell c is given by f _c (i).

For the PUSCH, it may be determined whether the TPC command operates in an accumulation mode or an absolute mode through RRC signaling. The accumulation mode is performed by adding or subtracting the TPC value received at the time point to the value accumulated up to the time point when the terminal receives the TPC command. In the absolute mode, the terminal applies the TPC value indicated in the TPC command immediately at the time point, and is maintained until the next TPC command is received. In particular, DCI format 3/3A transfers the TPC value in an accumulation mode regardless of RRC signaling. For PUCCH, it operates in an accumulation mode.

In the case of accumulation mode: If accumulation is activated by an upper layer in which accumulation is enabled for the serving cell c based on the accumulation-enabled parameter provided by higher layers, or the CRC is temporary When the TPC command δ _{PUSCH ,c} is included in the PDCCH/EPDCCH having DCI format 0 scrambled by -C-RNTI, f _c (i) is as shown in Equation 10 below.

In the case of an absolute mode: If accumulation is not activated for the serving cell c based on the accumulation-enabled parameter provided by higher layers, f _c (i) is expressed in Equation 11 below.

Here, δ _{PUSCH ,c} (iK _PUSCH ) is a TPC command in DCI format 0/4 or 3/3A in the PDCCH that was transmitted in the (iK _PUSCH )-th subframe, and f _c (0) is the first value after the reset of the accumulation to be.

For FDD, the K _PUSCH value is 4.

Regarding FDD, if the terminal is configured with more than one serving cell (configured with more than one serving cell) and the TDD UL/DL configurations of at least two configured serving cells are not the same, for serving cell c, "TDD UL /DL configuration" is interpreted as a UL-reference UL/DL configuration (refers to).

Regarding the TDD UL/DL configuration 1-6, K _PUSCH is given in Table 5 below.

Table 5 relates to an index K _PUSCH indicating the timing of the TPC command according to the subframe number (or index) and the TDD UL/DL configuration. Here, when the PUSCH is transmitted on the subframe i for the current serving cell c, the K _PUSCH is transmitted in the (iK _PUSCH )-th subframe in calculating the PUSCH power control adjustment state f _c (i) for the _PUSCH transmission. It indicates that it is based on the TPC command that was used. For example, when the TDD UL/DL configuration of the serving cell c is 1, when the UE transmits a PUSCH in subframe #9 (i=9) of the serving cell c, the PUSCH transmission power control for the PUSCH transmission is It may be performed based on the TPC command transmitted in the (iK _PUSCH )-th subframe of the serving cell c.

Regarding TDD UL/DL configuration 0, if PUSCH transmission in subframe 2 or 7 is scheduled with PDCCH/EPDCCH of DCI format 0/4, LSB (least significant bit) of UL index in DCI format 0/4 ) If the value is set to 1, K _PUSCH is 7.

For all other PUSCH transmissions, K _PUSCH is given in Table 3 above.

Meanwhile, the transmission power of the terminal for PUCCH transmission may also be set, and may be controlled by a TPC command. The TPC command for PUCCH transmission power is δ _PUCCH , which is a UE-specific correction value. The TPC command for PUCCH transmission power is included in the PDCCH carrying DCI format 1A/1B/1D/1/2A/2/2B/2C/2D for the primary serving cell. g(i) represents the current PUCCH power control adjustment state, and may be represented by the following equation.

In Equation 12, g(0) is an initial value after reset. For FDD, M=1 and k ₀ =4. If, P _{0 _ _} When the _{UE PUCCH} value is changed by an upper layer, and g (0) = 0, otherwise, g (0) = ΔP is _rampup + δ _msg2. Here, δ _msg2 is a TPC command indicated in the random access response, and corresponds to a random access preamble transmitted on the primary serving cell. ΔP _rampup is the total power ramp-up from the first to the last preamble in the primary serving cell provided by the upper layer.

Table 6 shows the mapping of the TPC command field in DCI format 1A/1B/1D/1/2A/2/2B/2C/2D/3 to the cumulative TPC value, and Table 7 shows the cumulative TPC command field in DCI format 3A. Represents mapping for TPC values.

TPC Command Field in
DCI format 1A/1B/1D/1/2A/2B/2C/2D/2/3 δ _PUCCH [dB] 0 -One One 0 2 One 3 3

TPC Command Field in
DCI format 3A δ _PUCCH [dB] 0 -One One One

Also, regardless of the accumulation mode or the absolute mode, the first values of δ _PUSCH,c and δ _PUCCH determined by the TPC command are determined through the RACH procedure.

When the first base station and the second base station configure dual connectivity for the terminal, when the terminal transmits a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH) to the first base station, the second base station is PRACH Transmission of a (physical random access channel) may be performed or a power filling technique may be applied. Power filling is a beneficial algorithm for a dedicated P _EMAX setting. Power filling is performed when there is sufficient power after transmission in the first cell group (CG) at the time of uplink transmission, and when transmission to the second cell group is insufficient, the first transmission to the second cell group is performed. This makes it possible to use more power of the cell group. In this way, when PUSCH or PUCCH transmission is affected by PRACH transmission or power filling, the UE may eventually perform PUSCH or PUCCH transmission to the first base station with less or more than the actually calculated transmission power (ie, uplink Transmit power fluctuation occurs). At this time, the network may erroneously recognize the fluctuation as a change in interference and may issue an incorrect TPC command. Therefore, there is a need for a method to avoid such erroneous TPC commands.

The present specification provides a terminal and a method of operating the terminal to avoid erroneous TPC commands. According to an embodiment, a method of rejecting an erroneous TPC command and a terminal performing the method are provided. According to another embodiment, a method of applying a TPC command by a terminal by itself compensating for a value changed through scaling down or power filling, and a terminal performing such a method are provided.

Here, if the priority of the first PRACH for the master base station is higher than the second PRACH for the secondary base station in the simultaneous PRACH transmission situation and scaling down occurs in the second PRACH transmission, the terminal is a TPC command transmitted through a random access response. Either reject the value or apply the TPC command by self-compensating for the changed value.

The RACH procedure includes a case where the UE performs PRACH transmission on a contention based basis and a case where PRACH transmission is performed on a non-contention based basis. For example, in order to perform PRACH transmission on a contention-free basis for the SeNB, a PDCCH order may be required for a secondary serving cell (or SCG or SeNB). However, in the case of a PSCell (SCell in which a PUCCH is configured), although it is a secondary serving cell, PRACH transmission may be performed in a contention based manner without a PDCCH indication.

[Embodiment 1] When PUCCH/PUSCH transmission is performed to one of the base stations (MeNB, SeNB) configuring dual connectivity, and PRACH transmission is performed to another base station, uplink power control is performed Is posted about how.

4 is a flowchart illustrating a method of performing uplink power control according to an example of the present invention. This is a case where PRACH transmission is performed to the SeNB.

Referring to FIG. 4, the master base station transmits an RRC message for configuring dual connectivity to the terminal (S400). Accordingly, the terminal receives an RRC message for configuring dual connectivity from the master base station. The RRC message for configuring a dual connection may be an RRC connection reconfiguration message.

The terminal calculates transmission power for each uplink channel (S405). It is assumed that the transmission power of the PUSCH calculated in step S405 is P _PUSCH , the transmission power of _PUCCH is P _PUCCH , and the PRACH transmission power is P _PRACH . Then, the terminal transmits the PUSCH and/or PUCCH to the first base station and transmits the PRACH to the second base station (S410). The first base station receives the PUSCH and/or PUCCH, and the second base station receives the PRACH.

Here, the transmission power of the PUSCH or PUSCH for the first base station was calculated as P _PUSCH or P _PUCCH in step S405, which causes simultaneous transmission of PUSCH and/or PUCCH and PRACH, and thereby occurs in PUSCH and/or PUCCH. According to the scaled power. Power scaling is only a temporary phenomenon due to simultaneous transmission of PRACH and PUSCH and/or PUCCH, and when PRACH is not considered, the UE may transmit the PUSCH and/or PUCCH with higher power. In FIG. 4, the first base station is indicated by MeNB and the second base station is indicated by SeNB, but the base stations through which PUSCH and/or PUCCH and PRACH are transmitted may be interchanged.

The first base station transmits a TPC command set based on the power of the received PUSCH and/or PUCCH to the terminal (S415). The TPC command in step S415 may be included in the DCI format and transmitted. Due to simultaneous transmission with the PRACH, the first base station receives the power scaled PUSCH and/or PUCCH. Since the first base station has received the PUSCH and/or PUCCH with low power, it can eventually transmit a TPC command requesting power increase. However, as described in step S410, when the PRACH is not transmitted at the same time, although the PUSCH and/or PUCCH can transmit high power without power scaling, the terminal receives the TPC command requesting power increase. Therefore, this corresponds to an unnecessary or incorrect TPC command.

The terminal may know that the TPC command of step S415 is unnecessary or incorrect. Accordingly, the terminal receiving the TPC command may perform uplink power control differently from (or irrespective of) the original TPC command (S420).

For example, since the TPC command may involve incorrect configuration, the UE does not apply the TPC command to the calculation of the next uplink power transmission. That is, the terminal maintains the previous value of the TPC command according to step S415. The previous value of the TPC command is an uplink transmission power parameter already calculated and stored by the terminal before the terminal receives the TPC command according to step S415, e.g., f _c (0), f _c (i), g (0 ), g(i), etc. The uplink power control in step S420 includes an operation of maintaining the previous value of the TPC command.

Alternatively, a value changed by scaling down or power filling generated by PRACH transmission may be calculated inside the terminal, and the TPC command value may be corrected and applied. That is, when the actual PUSCH and/or PUCCH transmission power fluctuation value is -2dB or 2dB due to scaling down or power filling, and the value received through the TPC command is 1dB, the terminal sends the TPC command 3dB (= 1dB + 2dB) or -1dB (=1dB-2dB), respectively, and used to calculate PUSCH and/or PUCCH transmission power. In this case, the uplink power control in step S420 includes an operation of calculating PUSCH and/or PUCCH transmission power by correcting the TPC command.

When the uplink power control is subdivided into embodiments in consideration of the type of the base station transmitting the PRACH and the priority (especially when the PRACH transmission for the SeNB has a higher priority than the uplink transmission for the MeNB), step S420 Uplink power control may include the following operations. The following description relates to the transmission power of the PUSCH, and the control of the transmission power of the PUCCH can be equally applied to the case of (1) the accumulation mode. However, in this case, g(*) will be used for PUCCH, not f _c (*).

(1) In the case of accumulation mode

As an example, when a terminal receives a TPC command from a serving cell c of another second serving cell group for the first time after performing PRACH transmission to a serving cell of a first serving cell group in dual connectivity, the TPC command is not accumulated. (If UE has received the first TPC command from serving cell c of one CG after PRACH transmission to any serving cell of the other CG in dual connectivity, the TPC command shall not be accumulated). In other words, i) dual connectivity is configured in the terminal, and ii) the terminal transmits PRACH to a random serving cell of the first base station (or first serving cell group: CG) configuring dual connectivity and the second The PUSCH and/or PUCCH is transmitted to the base station, and iii) the terminal receives the TPC command for the serving cell c in the second base station (or the second serving cell group) immediately after the PRACH transmission (the first reception Including), the terminal does not use the TPC command to calculate the PUSCH transmission power. That is, the TPC instruction is not accumulated in f _c (i).

As another example, when the UE receives a TPC command from the serving cell c of the SCG for the first time after performing PRACH transmission to a random serving cell of the MCG in dual connectivity, the TPC command is not accumulated (If UE has received the first TPC command from serving cell c of SCG after PRACH transmission to any serving cell of MCG in dual connectivity, the TPC command shall not be accumulated). In other words, i) a dual connection is configured to the terminal, and ii) a second PRACH is transmitted to a random serving cell of the first base station (or master cell group: MCG) in which the terminal configures the dual connection. When a UE receives a TPC command for a serving cell c in a second base station (or secondary cell group: SCG) immediately after transmission of the PUSCH and/or PUCCH to the base station, and iii) immediately after transmission of the PRACH (Including the case of first reception), the UE does not use the TPC command to calculate the PUSCH transmit power, that is, the TPC command is not accumulated in f _c (i).

As another example, when a terminal receives a TPC command for the first time from a serving cell c of another second serving cell group after performing PRACH transmission to a serving cell of a first serving cell group in dual connectivity, the TPC command is It is corrected and accumulated as scaling down (or up) (If UE has received the first TPC command from serving cell c of one CG after PRACH transmission to any serving cell of the other CG in dual connectivity, the TPC command shall be compensated as scaling down (or up) and accumulated). In other words, i) dual connectivity is configured in the terminal, and ii) the terminal transmits PRACH to a random serving cell of the first base station (or the first serving cell group (CG)) configuring the dual connectivity and simultaneously to the second base station. PUSCH and/or PUCCH is transmitted, and iii) the UE receives the TPC command for the serving cell c in the second base station (or the second serving cell group) immediately after transmission of the PRACH (including the first reception) , The UE scales up or down the TPC command by a predetermined size and uses it to calculate PUSCH transmission power. That is, the TPC instruction is scaled up or down and accumulated in f _c (i).

As another example, when the terminal receives a TPC command from the serving cell c of the SCG for the first time after performing PRACH transmission to a random serving cell of the MCG in dual connectivity, the TPC command is corrected such as scaling down (or up) (If UE has received the first TPC command from serving cell c of one CG after PRACH transmission to any serving cell of the other CG in dual connectivity, the TPC command shall be compensated as scaling down (or up) and accumulated) . In other words, i) dual connectivity is configured to the terminal, ii) the terminal performs PRACH transmission to a random serving cell of the first base station (or master serving cell group (MCG)) configuring dual connectivity, and iii) the PRACH Immediately after transmission, when the terminal receives a TPC command for a serving cell c in a second base station (or a secondary serving cell group (SCG) (including the case that it is initially received)), the terminal scales up the TPC command by a predetermined size. ) Or down and used to calculate the PUSCH transmission power, that is, the TPC command is scaled up or down and accumulated in f _c (i).

(2) Absolute mode

As an example, in dual connectivity, for a subframe that first receives a TPC command from a serving cell c of another second serving cell group after performing PRACH transmission to a serving cell of a first serving cell group, f _c (i )=f _c (i-1) is established (f _c (i)=f _c (i-1) for a subframe where UE has received the first TPC command from serving cell c of one CG after PRACH transmission to any serving cell of the other CG in dual connectivity). In other words, i) dual connectivity is configured in the terminal, and ii) the terminal transmits PRACH to a random serving cell of the first base station (or the first serving cell group (CG)) configuring the dual connectivity and simultaneously to the second base station. PUSCH and/or PUCCH is transmitted, and iii) for the subframe in which the terminal receives the TPC command for the serving cell c in the second base station (or the second serving cell group) immediately after transmission of the PRACH (when first received Including), the terminal calculates f _c (i) according to Equation 13 below.

According to this, the terminal does not use the TPC command to calculate PUSCH transmission power. That is, the TPC instruction is not accumulated in f _c (i).

As another example, for a subframe that receives a TPC command for the first time from a serving cell c of the SCG after the UE performs PRACH transmission to an arbitrary serving cell of the MCG in dual connectivity, f _c (i) = f _c (i- 1) This is established (f _c (i) = f _c (i-1) for a subframe where UE has received the first TPC command from serving cell c of SCG after PRACH transmission to any serving cell of the MCG in dual connectivity) . In other words, i) dual connectivity is configured in the terminal, and ii) PUSCH to the second base station simultaneously with PRACH transmission to a random serving cell of the first base station (or master serving cell group (MCG)) in which the terminal configures dual connectivity And/or PUCCH transmission, and iii) immediately after transmission of the PRACH, with respect to the serving cell c in the second base station (or the secondary serving cell group (SCG)), for the subframe in which the terminal receives the TPC command (when initially received Including), the terminal calculates f _c (i) according to Equation 13. According to this, the terminal does not use the TPC command to calculate the PUSCH transmission power, that is, the TPC command is in f _c (i). Does not accumulate.

이 성립한다(

for a subframe where UE has received the first TPC command from serving cell c of one CG after PRACH transmission to any serving cell of the other CG in dual connectivity). 다시 말하면, i) 단말에 이중 연결이 구성되고, ii) 단말이 이중연결을 구성하는 제1 기지국(또는 제1 서빙셀 그룹(CG))의 임의 서빙셀로 PRACH 전송과 동시에 제2 기지국으로의 PUSCH 및/또는 PUCCH의 전송을 수행하며, iii) 상기 PRACH 전송 직후 제2 기지국(또는 제2 서빙셀 그룹)내의 서빙셀 c에 관하여 단말이 TPC 명령을 수신한 경우(최초로 수신한 경우를 포함), 단말은 다음의 수학식 14에 따라 f_c(i)를 계산한다. As another example, in dual connectivity, for a subframe that receives a TPC command for the first time from a serving cell c of another second serving cell group after performing PRACH transmission to a serving cell of a first serving cell group,

This is established (

for a subframe where UE has received the first TPC command from serving cell c of one CG after PRACH transmission to any serving cell of the other CG in dual connectivity). In other words, i) dual connectivity is configured in the terminal, and ii) the terminal transmits PRACH to a random serving cell of the first base station (or the first serving cell group (CG)) configuring the dual connectivity and simultaneously to the second base station. PUSCH and/or PUCCH is transmitted, and iii) the UE receives the TPC command for the serving cell c in the second base station (or the second serving cell group) immediately after transmission of the PRACH (including the first reception) , The terminal calculates f _c (i) according to Equation 14 below.

Referring to Equation 14, the UE scales up or down a value δ _{PUSCH ,c} (iK _PUSCH ) according to the TPC command by a predetermined size ΔP _scaling , and uses it to calculate PUSCH transmission power. That is, the TPC instruction is scaled up or down and accumulated in f _c (i).

이 성립한다(

for a subframe where UE has received the first TPC command from serving cell c of SCG after PRACH transmission to any serving cell of the MCG in dual connectivity). 다시 말하면, i) 단말에 이중 연결이 구성되고, ii) 단말이 이중연결을 구성하는 제1 기지국(또는 마스터 서빙셀 그룹(MCG))의 임의 서빙셀로 PRACH 전송과 동시에 제2 기지국으로의 PUSCH 및/또는 PUCCH의 전송을 수행하며, iii) 상기 PRACH 전송 직후 제2 기지국(또는 세컨더리 서빙셀 그룹(SCG)내의 서빙셀 c에 관하여 단말이 TPC 명령을 수신한 경우(최초로 수신한 경우를 포함), 단말은 상기 수학식 14에 따라 f_c(i)를 계산한다. 이에 따르면 단말은 TPC 명령에 따른 값 δ_{PUSCH ,c}(i-K_PUSCH)을 소정 크기 ΔP_scaling 만큼 스케일링 업(scaling up) 또는 다운(down)하여 PUSCH 전송 전력의 계산에 사용한다. 즉, TPC 명령은 스케일링 업 또는 다운되어 f_c(i)에 누적된다. As another example, for a subframe that receives a TPC command for the first time from a serving cell c of the SCG after the UE performs PRACH transmission to a random serving cell of the MCG in dual connectivity,

This is established (

for a subframe where UE has received the first TPC command from serving cell c of SCG after PRACH transmission to any serving cell of the MCG in dual connectivity). In other words, i) dual connectivity is configured in the terminal, and ii) PUSCH to the second base station simultaneously with PRACH transmission to a random serving cell of the first base station (or master serving cell group (MCG)) in which the terminal configures dual connectivity And/or performing PUCCH transmission, and iii) when the terminal receives the TPC command for the serving cell c in the second base station (or secondary serving cell group (SCG)) immediately after transmission of the PRACH (including the case of initial reception) , The UE calculates f _c (i) according to Equation 14. Accordingly, the UE scales up or down the values δ _{PUSCH ,c} (iK _PUSCH ) according to the TPC command by a predetermined size ΔP _scaling ( down) and used to calculate PUSCH transmission power, that is, the TPC command is scaled up or down and accumulated in f _c (i).

4 illustrates a case in which PUSCH and/or PUCCH transmission to the MeNB has a lower priority than PRACH transmission to the SeNB as an example. If PUSCH and/or PUCCH transmission to the MeNB has a higher priority than PRACH transmission to the SeNB, the TPC command by the MeNB may be applied in the same manner as in the general case, not this embodiment.

Meanwhile, according to the present embodiment, the UE can adaptively correct or maintain uplink power control for a TPC command transmitted in error by the network due to PRACH transmission or power filling in dual connection.

5 is a flowchart illustrating a method of performing uplink power control according to another example of the present invention. This is a case where PRACH transmission is performed to the MeNB.

5, the master base station transmits an RRC message for configuring dual connectivity to the terminal (S500). The RRC message for configuring dual connectivity may be an RRC connection reconfiguration message.

The UE calculates transmission power for each uplink channel (S505). It is assumed that the transmission power of the PUSCH calculated in step S505 is P _PUSCH , the transmission power of the _PUCCH is P _PUCCH , and the PRACH transmission power is P _PRACH . Then, the terminal transmits the PRACH to the first base station, and transmits the PUSCH and/or the PUCCH to the second base station (S510). The second base station receives the PUSCH and/or PUCCH, and the first base station receives the PRACH.

Here, the transmission power of the PUSCH or the PUSCH for the second base station was calculated as P _PUSCH or P _PUCCH in step S505, which causes simultaneous transmission of PUSCH and/or PUCCH and PRACH, and thereby occurs in PUSCH and/or PUCCH. According to the scaled power. Power scaling is only a temporary phenomenon due to simultaneous transmission of PRACH and PUSCH and/or PUCCH, and when PRACH is not considered, the UE may transmit the PUSCH and/or PUCCH with higher power. In FIG. 5, the first base station is indicated by SeNB and the second base station is indicated by MeNB, but the base stations through which PUSCH and/or PUCCH and PRACH are transmitted may be interchanged.

The second base station transmits a TPC command set based on the power of the received PUSCH and/or PUCCH to the terminal (S515). The TPC command in step S515 may be included in the DCI format and transmitted. Due to simultaneous transmission with the PRACH, the second base station receives the power scaled PUSCH and/or PUCCH. Since the second base station has received the PUSCH and/or PUCCH with low power, it may eventually transmit a TPC command requesting power increase. However, this is, as described in step S510, when the PRACH is not transmitted at the same time, although the PUSCH and/or PUCCH can transmit high power without power scaling, the terminal receives a TPC command requesting power increase. Therefore, this corresponds to an unnecessary or incorrect TPC command.

The terminal may know that the TPC command in step S515 is unnecessary or incorrect. Accordingly, the terminal receiving the TPC command may perform uplink power control differently from (or irrespective of) the original TPC command (S520). For example, since the TPC command may involve incorrect configuration, the UE does not apply the TPC command to the calculation of the next uplink power transmission. That is, the terminal maintains the previous value of the TPC command according to step S515. The previous value of the TPC command is an uplink transmission power parameter that has already been calculated and stored before the terminal receives the TPC command according to step S415, for example, f _c (0), f _c (i), g (0), and g(i). Accordingly, the uplink power control in step S520 includes an operation of maintaining the previous value of the TPC command. Alternatively, a value changed by scaling down or power filling generated by PRACH transmission may be calculated inside the terminal, and the TPC command value may be corrected and applied. That is, when the actual PUSCH and/or PUCCH transmission power fluctuation value is -2dB or 2dB due to scaling down or power filling, when the value received through the TPC command is 1dB, the terminal sends the TPC command 3dB or -1dB. Each is corrected to and used for calculation of PUSCH and/or PUCCH transmission power. In this case, the uplink power control in step S520 includes performing uplink power control by correcting the TPC command and using it for calculation of PUSCH and/or PUCCH transmission power.

When the uplink power control is subdivided into embodiments in consideration of the type of the base station transmitting the PRACH and the priority (especially, when the PRACH transmission for the SeNB has a higher priority than the uplink transmission for the MeNB), step S520 The same scheme as described in FIG. 4 may be applied to the uplink power control.

[Embodiment 2] When PRACH transmission is performed to all base stations (MeNB and SeNB) configuring dual connectivity, a method of performing uplink power control is disclosed. The following description relates to the transmission power of the PUSCH, and can be equally applied to the control of the transmission power of the PUCCH. However, in this case, g(*) will be used for PUCCH, not f _c (*).

6 is a flowchart illustrating a method of performing uplink power control according to another example of the present invention.

6, the master base station transmits an RRC message for configuring dual connectivity to the terminal (S600). The RRC message for configuring dual connectivity may be an RRC connection reconfiguration message.

The terminal calculates the transmission power for each uplink channel (S605). It is assumed that the transmission power of PRACH1 for the SeNB calculated in step S605 is P _PRACH1 , and the transmission power of PRACH2 for the MeNB is P _PRACH2 . Then, the UE transmits PRACH1 to the SeNB and simultaneously transmits PRACH2 to the MeNB (S610). Then, the SeNB receives PRACH1 and the MeNB receives PRACH2.

The SeNB transmits a TPC command to the terminal (S615). The TPC command of step S615 is included in a random access response (RAR) for PRACH1 and transmitted. Here, the TPC command may be determined based on the power of PRACH2 received by the SeNB. In this case, the TPC command may be used to set the first value for f _c (*). The initial value for f _c (*) is f _c (0), which can be calculated as in Equation 15 below.

Referring to Equation 15, δ _{msg2 ,c} corresponds to a TPC command value included in the RAR in the serving cell c. In addition, ΔP _rampup is a total power ramp-up from the first to the last preamble in the primary serving cell (or secondary primary serving cell) provided by the upper layer.

The terminal may know that the TPC command of step S615 is unnecessary or incorrect. Accordingly, the terminal receiving the TPC command may perform uplink power control differently from (or irrespective of) the original TPC command (S620). The uplink power control according to step S620 may include the following embodiments.

As an example, since the TPC command may involve incorrect configuration, the terminal does not apply the TPC command to the calculation of the next uplink power transmission. That is, the terminal maintains the value of f _c (*) before the TPC command according to step S615 is received. The previous f _c (*) value may be a value previously stored in the terminal. In this case, the uplink power control in step S620 includes an operation of maintaining the value of f _c (*) before the TPC command is received. For example, the terminal may set δ _{msg2 ,c} = 0 in Equation 15.

As another example, the UE calculates a value that is changed by scaling down or power filling caused by PRACH transmission, corrects the received TPC command value based on the changed value, and uses the corrected value as PUSCH and/or PUCCH. It can also be applied to the calculation of the transmission power. For example, the terminal is a TPC command value δ _{msg2 , c} = P _scaling in Equation 15 It can be corrected (or set) _{up / down} , and f _c (0) can be calculated by substituting the corrected δ _{msg2 ,c} into Equation 15. Where P _{scaling up / down} corresponds to a value that has changed due to power scaling down or scaling up.

6 shows an embodiment applied when the PRACH2 transmission to the MeNB has a lower priority than the PRACH1 transmission to the SeNB and when the priority is the same. If the PRACH2 transmission to the MeNB has a higher priority than the PRACH1 transmission to the SeNB, the TPC command by the MeNB may be applied in the same manner as in the general case, not in this embodiment.

7 is a flowchart illustrating a method of performing uplink power control according to another example of the present invention.

Referring to FIG. 7, the master base station transmits an RRC message for configuring dual connectivity to the terminal (S700). The RRC message for configuring dual connectivity may be an RRC connection reconfiguration message.

The UE calculates transmission power for each uplink channel (S705). It is assumed that the transmission power of PRACH1 for the SeNB calculated in step S705 is P _PRACH1 , and the PUSCH and PUCCH transmission powers for the MeNB are P _PUCCH and P _PUSCH , respectively. Then, the UE transmits PRACH1 to the SeNB, and simultaneously transmits the PUSCH and/or PUCCH to the MeNB (S710). And, SeNB receives PRACH1, MeNB receives PUSCH and/or PUCCH.

The MeNB can transmit the TPC to the terminal through DCI (S715), and the SeNB can transmit the TPC command to the terminal through RAR (S720). The TPC command of step S720 is included in a random access response (RAR) for PRACH1 and transmitted. Here, the TPC command may be determined based on the power of PRACH2 received by the SeNB. In this case, the TPC command may be used to set the first value for f _c (*). The initial value for f _c (*) is f _c (0), which can be calculated as in Equation 16 below.

Referring to Equation 16, δ _{msg2 ,c} corresponds to a TPC command value included in the RAR in the serving cell c. In addition, ΔP _rampup is a total power ramp-up from the first to the last preamble in the primary serving cell (or secondary primary serving cell) provided by the upper layer.

The terminal may know that the TPC command of step S720 is unnecessary or incorrect. Accordingly, the terminal receiving the TPC command may perform uplink power control differently from (or irrespective of) the original TPC command (S725). The uplink power control according to step S725 may include the following embodiments.

As an example, since the TPC command may involve incorrect configuration, the terminal does not apply the TPC command to the calculation of the next uplink power transmission. That is, the terminal maintains the value of f _c (*) before the TPC command according to step S720 is received. The previous f _c (*) value may be a value previously stored in the terminal. In this case, the uplink power control in step S725 includes an operation of maintaining the value of f _c (*) before the TPC command is received. For example, the terminal may set δ _{msg2 ,c} = 0 in Equation 16.

As another example, the UE calculates a value that is changed by scaling down or power filling caused by PRACH transmission, corrects the received TPC command value based on the changed value, and uses the corrected value as PUSCH and/or PUCCH. It can also be applied to the calculation of the transmission power. For example, the terminal is a TPC command value δ _{msg2 , c} = P _scaling in Equation 16 It can be corrected (or set) _{up / down} , and f _c (0) can be calculated by substituting the corrected δ _{msg2 ,c} into Equation 16. Where P _{scaling up / down} corresponds to a value that has changed due to power scaling down or scaling up.

7 shows an embodiment applied when PUSCH or PUCCH transmission to the MeNB has a lower priority than PRACH1 transmission to the SeNB, and when the priority is the same. If PUSCH or PUCCH transmission to the MeNB has a higher priority than PRACH1 transmission to the SeNB, the TPC command by the MeNB may be applied in the same manner as in the general case, not in this embodiment.

Priorities posted in this specification may be determined according to various embodiments. Table 8 below is an embodiment showing the priority between an uplink channel or uplink signals transmitted to the MeNB and SeNB constituting dual connectivity.

Example Priority One MeNB’s PRACH>SeNB’s PRACH>MeNB’s PUCCH>SeNB’s PUCCH>MeNB’s PUSCH with UCI>SeNB’s PUSCH with UCI>MeNB’s PUSCH without UCI>SeNB’s PUSCH without UCI>SRS 2 MeNB’s PRACH>SeNB’s PRACH>MeNB’s PUCCH>MeNB’s PUSCH with UCI>MeNB’s PUSCH without UCI>SeNB’s PUCCH>SeNB’s PUSCH with UCI>SeNBs’ PUCCH without UCI>SRS 3 MeNB’s transmission(PRACH>PUCCH>PRACH with UCI >PRACH without UCI)>SeNB’s transmission(PRACH>PUCCH>PRACH with UCI>PRACH without UCI)>SRS 4 MeNB’s PRACH=SeNB’s PRACH>MeNB’s PUCCH>SeNB’s PUCCH>MeNB’s PUSCH with UCI>SeNB’s PUSCH with UCI>MeNB’s PUSCH without UCI>SeNB’s PUSCH without UCI>SRS 5 MeNB’s PRACH=SeNB’s PRACH>MeNB’s PUCCH>MeNB’s PUSCH with UCI>MeNB’s PUSCH without UCI>SeNB’s PUCCH>SeNB’s PUSCH with UCI>SeNBs’ PUCCH without UCI>SRS

Referring to Table 8, x>y indicates that x has a higher priority than y. For example, since MeNB's PRACH>SeNB's PRACH in Embodiment 1, it indicates that the PRACH of the MeNB has a higher priority than the PRACH of the SeNB. In either case, the SRS is always the lowest priority.

Meanwhile, according to the present embodiment, the UE can adaptively correct or maintain uplink power control for a TPC command transmitted in error by the network due to PRACH transmission or power filling in dual connection.

8 is a block diagram showing a wireless communication system in which an embodiment of the present invention is implemented.

Referring to FIG. 8, a terminal 800 includes a radio frequency (RF) unit 805, a processor 810, and a memory 815. The memory 815 is connected to the processor 810 and stores various pieces of information for driving the processor 810. The RF unit 805 is connected to the processor 810 and transmits and/or receives a radio signal. For example, the RF unit 805 may receive an RRC message for dual connectivity posted in this specification from the base station 850. In addition, the RF unit 805 may transmit an uplink channel or uplink signal such as PUSCH, PUCCH, and PRACH published in this specification to the base station 850.

Processor 810 implements the proposed function, process and/or method. Specifically, the processor 810 performs steps S405, S420, S505, S520, S605, S620, S705, and S725 according to FIGS. 4 to 6. For example, the processor 810 may control uplink transmission power according to an embodiment of the present invention. In all embodiments of the present specification, the operation of the terminal 800 may be implemented by the processor 810.

The memory 815 may store uplink power control parameters such as fc(*) and g(*) according to the present specification, and provide the corresponding parameters to the processor 810 according to the request of the processor 810.

The base station 850 includes a processor 855, a memory 860, and a radio frequency (RF) unit 53. The memory 860 is connected to the processor 855 and stores various information for driving the processor 855. The RF unit 865 is connected to the processor 855 and transmits and/or receives a radio signal. Processor 855 implements the proposed functions, processes and/or methods. In the above-described embodiment, the operation of the base station may be implemented by the processor 855. The processor 855 generates an RRC message published in this specification, sets a TPC command, and generates a DCI format including a TPC command or an RAR including a TPC command. The RF unit 865 transmits an RRC message, a DCI format including a TPC command, or an RAR including a TPC command to the terminal 800.

The present invention may include an embodiment in which the memories 815 and 860 are omitted from among the components constituting the terminal 800 and the base station 850.

The processor may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and/or a data processing device. The memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and/or other storage device. The RF unit may include a baseband circuit for processing a radio signal. When the embodiment is implemented as software, the above-described technique may be implemented as a module (process, function, etc.) that performs the above-described functions. The modules are stored in memory and can be executed by the processor. The memory may be inside or outside the processor, and may be connected to the processor by various well-known means.

In the exemplary system described above, the methods are described on the basis of a flowchart as a series of steps or blocks, but the present invention is not limited to the order of the steps, and certain steps may occur in a different order or concurrently with the steps described above. I can. In addition, those skilled in the art will appreciate that the steps shown in the flowchart are not exclusive, other steps are included, or one or more steps in the flowchart may be deleted without affecting the scope of the present invention.

Claims (10)

As a method for controlling uplink transmission power by a terminal in a wireless communication system supporting dual connectivity,
Receiving a radio resource control (RRC) message for the configuration of the dual connection from a first base station;
Calculating a first transmission power for a first physical channel to be transmitted to the first base station and a second transmission power for a second physical channel to be transmitted to a second base station, wherein the first transmission power is a priority Scaled according to or adjusted by power filling, wherein at least one of the first physical channel and the second physical channel is a physical random access channel (PRACH);
Simultaneously transmitting the first physical channel and the second physical channel to the first base station and the second base station, respectively;
Receiving a transmit power control (TPC) command from the first base station; And
Unlike the TPC command, performing uplink power control for the first physical channel
Including, wherein the TPC command is set by the first base station based on the first transmission power, the first physical channel is transmitted on the serving cell c,
The step of performing uplink power control,
Correcting a value indicated by the TPC command based on at least one of the scaling and the power filling; And
Reflecting the correction to a current power control adjustment state of the first physical channel for the serving cell c
Uplink power control method further comprising a. The method of claim 1,
The first physical channel is transmitted on the serving cell c,
The performing of uplink power control includes maintaining a current power control adjustment state of the first physical channel for the serving cell c as it is. delete The method of claim 1,
The first physical channel is at least one of a physical uplink common channel (PUSCH) and a physical uplink control channel (PUCCH), and the second physical channel is a PRACH,
The method of controlling uplink power, characterized in that both the first physical channel and the second physical channel are PRACHs. The method of claim 1,
Any one of the first base station and the second base station is a master base station, and the other is a secondary base station. As a terminal controlling uplink transmission power in a wireless communication system supporting dual connectivity,
A radio frequency (RF) unit for receiving a radio resource control (RRC) message for configuring the dual connection from a first base station; And
A processor for calculating a first transmission power for a first physical channel to be transmitted to the first base station and a second transmission power for a second physical channel to be transmitted to a second base station,
The first transmission power is scaled according to a priority or adjusted by power filling, and at least one of the first physical channel and the second physical channel is a physical random access channel (PRACH),
The RF unit simultaneously transmits the first physical channel and the second physical channel to the first base station and the second base station, respectively, and transmits a transmit power control (TPC) command from the first base station. Receive,
Unlike the TPC command, the processor performs uplink power control for the first physical channel, wherein the TPC command is set by the first base station based on the first transmission power,
The RF unit transmits the first physical channel on a serving cell c,
The processor corrects the value indicated by the TPC command based on at least one of the scaling and the power filling, and reflects the correction to the current power control adjustment state of the first physical channel for the serving cell c. Terminal characterized by. The method of claim 6,
The RF unit transmits the first physical channel on a serving cell c,
Wherein the processor maintains a current power control adjustment state of the first physical channel for the serving cell c as it is. delete The method of claim 6,
The first physical channel is at least one of a physical uplink common channel (PUSCH) and a physical uplink control channel (PUCCH), and the second physical channel is a PRACH,
The terminal, characterized in that both the first physical channel and the second physical channel are PRACH The method of claim 6,
Any one of the first base station and the second base station is a master base station, and the other is a secondary base station.

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