Method for controlling transmission power, and apparatus for same

The present invention relates to a wireless communication system, and more particularly to a method for controlling uplink transmission power and a device for that purpose.

Wireless communication systems have been extensively deployed to provide a wide variety of communication services such as voice or data. In general, a wireless communication system is a multiple access system that can support communication with a plurality of users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple connection (TDMA) systems, orthogonal frequency division multiple connection (OFDMA) systems, and single carrier frequency division. There are multiple connection (SC-FDMA) systems, multiple carrier frequency division multiple connection (MC-FDMA) systems, and so on.

<p> An object of the present invention is to provide a method and an apparatus for efficiently controlling transmission power when transmitting a plurality of signals in a wireless communication system.</p><p> Another object of the present invention is to provide a method and an apparatus for efficiently controlling the transmission power when the sum of the transmission powers of the signals exceeds the maximum transmission power when transmitting a plurality of signals. ..</p><p> The technical problem to be solved by the present invention is not limited to the technical problem mentioned above, and another technical problem not mentioned is the ordinary knowledge in the technical field to which the present invention belongs from the following description. Will be clearly understood by those who have.</p>

<p> One aspect of the present invention is a method in which a terminal transmits a signal in a wireless communication system, in which a step of independently determining the transmission power of the first channel and the transmission power of the second channel and the transmission power of the first channel are described. And when the sum of the transmission powers of the second channel exceeds the maximum transmission power, at least one of the transmission power of the first channel or the transmission power of the second channel is reduced in consideration of the channel priority. A signal transmission method including a step of causing the base station to transmit a signal simultaneously through the first channel and the second channel is provided.</p><p> As another aspect of the present invention, a radio frequency (RF) unit configured to transmit and receive a radio signal to and from a base station, information to be transmitted and received between the base station, and necessary for the operation of the terminal. A memory for storing parameters and a processor connected to the RF unit and the memory and configured to control the RF unit and the memory for the operation of the terminal, wherein the processor includes the RF unit and a processor configured to control the memory. , Channel priority when the sum of the transmission power of the first channel and the transmission power of the second channel independently determines the transmission power of the first channel and the transmission power of the second channel exceeds the maximum transmission power. In consideration of the order, a step of reducing at least one of the transmission power of the first channel or the transmission power of the second channel and a signal to the base station are simultaneously transmitted to the base station through the first channel and the second channel. A terminal is provided that is configured to perform a transmission step and a signal transmission method including.</p><p> Here, the first channel and the second channel can each contain one or more SC-FDMA symbols. On the other hand, the channel priority may be determined in consideration of at least one of the channel type or the information on the channel. The first channel and the second channel can each include any one of a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a measurement reference signal (SRS).</p><p> Here, when both the first channel and the second channel are PUSCH, the channel priority is determined in consideration of at least one of the transmission format, whether or not it is retransmission, or the number of retransmissions. You may. Further, when the transmission power of the PUSCH is reduced, the modulation coding method (MCS) applied to the PUSCH can be controlled to be low in consideration of the amount of the reduced power. Further, when the first channel is the PUCCH carrying the ACK and the second channel is the PUSCH, a higher channel priority may be set for the PUSCH.</p><p> As yet another aspect of the present invention, in a method in which a terminal transmits a signal in a wireless communication system, the maximum transmission power (P_CC_MAX) for each component carrier wave and the maximum transmission power (P_UE_MAX) of the terminal are set for a plurality of component carrier waves. The step of checking, the step of calculating the transmission power of each of the multiple channels scheduled to be transmitted to the base station at the same time through one or more component carriers, and the step of not exceeding the above P_CC_MAX and the above P_UE_MAX. A signal transmission method including a step of independently adjusting the transmission power of the plurality of channels and a step of transmitting a signal to the base station through the plurality of channels in which the transmission power is adjusted is provided.</p><p> As yet another aspect of the present invention, an RF unit configured to transmit and receive radio signals to and from a base station, and a memory for storing information to be transmitted and received between the base stations and parameters necessary for the operation of the terminal. , The RF unit and a processor connected to the memory and configured to control the RF unit and the memory for the operation of the terminal, wherein the processor includes a plurality of component carriers. , At the stage of confirming the maximum transmission power (P_CC_MAX) by component carrier wave and the maximum transmission power (P_UE_MAX) of the above terminal, and for multiple channels scheduled to be transmitted to the base station simultaneously through one or more component carrier waves. Through the stage of calculating each transmission power, the stage of independently adjusting the transmission power of the plurality of channels so as not to exceed the above P_CC_MAX and the above P_UE_MAX, and the stage of adjusting the transmission power of the plurality of channels, the base A terminal is provided that is configured to perform a signal transmission method including a step of transmitting a signal to a station.</p><p> The information for setting the P_CC_MAX or the information for setting the P_UE_MAX may be notified through a broadcast message or a radio resource control (RRC) message.</p><p> The steps of adjusting the transmission power of the plurality of channels are the step of independently reducing the transmission power of each channel and the transmission power of each channel so that the sum of the transmission powers of the plurality of channels does not exceed the P_UE_MAX. After the reduction, the transmission power of the corresponding channel can be independently reduced so that the sum of the transmission powers of the corresponding channels does not exceed the corresponding P_CC_MAX for each component carrier wave. In this case, at least a portion of the power reduced from the corresponding channel above so as not to exceed the corresponding P_CC_MAX may be used to increase the transmit power of the other component carrier.</p><p> The step of adjusting the transmission power of the plurality of channels is the step of independently reducing the transmission power of the corresponding channel so that the sum of the transmission power of the corresponding channel does not exceed the corresponding P_CC_MAX for each component carrier wave. After reducing the transmission power of each of the channels, the step of independently reducing the transmission power of each channel so that the sum of the transmission powers of the plurality of channels does not exceed P_UE_MAX can be included.</p><p> The step of adjusting the transmission power for the plurality of channels can be performed by applying the attenuation coefficient independently for each channel.</p><p> Each channel can contain one or more SC-FDMA symbols. In this case, each channel can include any one of PUSCH, PUCCH or SRS.</p><p> As yet another aspect of the present invention, in a method in which a terminal transmits a signal in a wireless communication system, a step of calculating the transmission power of each of a plurality of antennas and the calculated transmission power of each antenna are combined with each other. When the maximum transmission power of the corresponding antenna is exceeded, the stage of calculating the transmission power attenuation ratio, the stage of applying the maximum attenuation ratio to the plurality of antennas in the same one or more transmission power attenuation ratios, and the above-mentioned plurality of stages. A signal transmission method including a step of transmitting a signal to a base station through an antenna is provided.</p>

<p> According to the embodiment of the present invention, when transmitting a plurality of signals in a wireless communication system, the transmission power can be efficiently controlled. Further, when the sum of the transmission powers of the signals exceeds the maximum transmission power, the transmission power can be efficiently controlled.</p>

The accompanying drawings, which are included as part of a detailed description to aid understanding of the present invention, provide examples of the present invention, and explain the technical idea of the present invention together with the detailed description, are described below. It's a street.<figref num="1">It is a figure which shows the network structure of the reinforced mobile communication system (E-UMTS).</figref><figref num="2">It is a figure which shows the wireless interface protocol structure between the terminal based on the 3GPP wireless connection network standard, and the terrestrial wireless connection network (E-UTRAN) for enhanced broadcasting.</figref><figref num="3">It is a block diagram which shows a transmitter and a receiver for OFDMA and SC-FDMA.</figref><figref num="4">It is a figure which shows the structure of the radio frame used in the long-term evolution system (LTE).</figref><figref num="5">It is a figure which shows the example which communicates under the single component carrier wave environment.</figref><figref num="6A">It is a figure which shows the structure of the uplink subframe used in LTE.</figref><figref num="6B">It is a figure which shows the structure of the uplink control channel used in LTE.</figref><figref num="7">It is a figure which shows the example which communicates under the multi-component carrier wave environment.</figref><figref num="8">It is a figure which shows the example which adjusts the transmission power according to the Example of this invention.</figref><figref num="9">It is a figure which shows the example of transmitting a plurality of signals by an Example of this invention.</figref><figref num="10">It is a figure which shows the example which adjusts the transmission power by the Example of this invention when the maximum transmission power is limited by one or more component carrier wave units.</figref><figref num="11">It is a figure which shows the other example which adjusts the transmission power by the Example of this invention when the maximum transmission power is limited by one or more component carrier wave units.</figref><figref num="12">It is a figure which shows the base station and the terminal which can apply to one Example of this invention.</figref>

Hereinafter, the configurations, actions and other features of the invention will be readily understood from the embodiments of the invention described with reference to the accompanying drawings. The embodiments of the present invention may be used for various wireless connection technologies such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, and MC-FDMA. CDMA can be implemented by general purpose terrestrial radio connectivity (UTRA) or radio technologies such as CDMA2000. TDMA can be realized by wireless technologies such as Global Mobile Communication Systems (GSM®) / General Packet Radio Service (GPRS) / GSM Evolutionary Enhanced Data Rate (EDGE). OFDMA can be realized by wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.11, and E-UTRA. UTRA is part of the Mobile Network Operator (UMTS) for general purpose. LTE in 3GPP is part of E-UMTS using E-UTRA. Advanced LTE (LTE-A) is an evolved version of 3GPP LTE.

The following examples will be described with reference to the case where the technical features of the present invention are applied to a 3GPP system, but this is exemplary and the present invention is not limited thereto.

FIG. 1 is a diagram showing a communication network structure of E-UMTS. E-UMTS is also called an LTE system. For the detailed contents of the UMTS and E-UMTS technical standards, refer to Release 7 and Release 8 of the "3rd Generation Partnership Project; Technical Specification Group Radio Access Network", respectively.

Referring to FIG. 1, E-UMTS is a connection barrier device located at the end of terminal (UE) 120, base station (eNB) 110a, 110b, and communication network (E-UTRAN) and connected to an external network. Including AG). Base stations can simultaneously transmit multiple data streams for broadcast services, multicast services and / or unicast services. One base station covers one or more cells. The cell can be any one of bandwidths such as 1.25, 2.5, 5, 10, 15, 20MHz. Different cells may have different bandwidths. The base station controls data transmission / reception to a large number of terminals. For downlink (DL) data, the base station sends downlink schedule information, and the time / frequency domain, encoding, data size, hybrid automatic repeat request (HARQ) related information at which the data is transmitted to the corresponding terminal. And so on. In addition, for uplink (UL) data, the base station sends uplink schedule information to the relevant terminal to provide the time / frequency domain, coding, data size, HARQ-related information, etc. that can be used by the relevant terminal. Inform. The core communication network (CN) can be composed of a communication network node or the like for user registration of AG and terminals. AG manages the mobility of terminals in units of tracking range (TA) consisting of multiple cells.

FIG. 2 is a diagram showing the structure of the control plane and the user plane of the wireless interface protocol between the terminal and E-UTRAN based on the 3GPP wireless connection network standard. The control plane means a route through which control messages used by terminals and communication networks to manage calls are transmitted. The user plane means a route through which data generated in the application layer, such as voice data or Internet packet data, is transmitted.

The physical layer (PHY), which is the first layer, provides an information transfer service to an upper layer using a physical channel. The physical layer is connected through an upper medium connection control (MAC) layer and a transport channel. Data moves between the MAC layer and the PHY layer through the transmission channel. Data moves between the transmitting PHY layer and the receiving PHY layer through a physical channel. Physical channels use time and frequency as radio resources. Specifically, the physical channel is modulated by the OFDMA method in the downlink and by the SC-FDMA method in the uplink.

The media connection control layer of the second layer provides services to the wireless link control (RLC) layer, which is an upper layer, through a logical channel. The second layer, RLC layer, supports highly reliable data transmission. The function of the RLC layer may be embodied by a functional block inside the MAC. The second layer, the Packet Data Fusion Protocol (PDCP) layer, performs a header compression function that reduces extra control information in order to efficiently transmit IP packets such as IPv4 or IPv6 over narrow bandwidth wireless interfaces.

The Radio Resource Control (RRC) layer, located at the bottom of the third layer, is defined only in the control plane. The RRC layer is responsible for controlling logical, transmit and physical channels in connection with the configuration, reconfiguration and deconfiguration of radio bearers (RBs). RB means the service provided by the second layer for the transmission of data between the terminal and the communication network. For this purpose, the RRC layer of the terminal and the communication network exchanges RRC messages. If there is an RRC connected between the RRC layers of the terminal and the communication network, the terminal is put into the RRC connection state, otherwise it is put into the RRC hibernation state. The non-connected layer (NAS) above the RRC layer performs functions such as session management and mobility management.

The downlink transmission channel that transmits data from the communication network to the terminal is a broadcast channel (BCH) that transmits system information, a paging channel (PCH) that transmits paging messages, and a downlink shared channel that transmits user traffic or control messages. (DL-SCH) and so on. On the other hand, the uplink transmission channel for transmitting data from the terminal to the communication network includes a random access channel (RACH) for transmitting an initial control message and an uplink shared channel (UL-SCH) for transmitting a user traffic or a control message. ..

FIG. 3 is a block diagram showing transmitters and receivers for OFDMA and SC-FDMA. In the uplink, transmitters 402-414 are part of the terminal and receivers 416-430 are part of the base station. In the downlink, the transmitter is part of the base station and the receiver is part of the terminal.

Referring to FIG. 3, the OFDM transmitters are series / parallel converter 402, subcarrier mapping module 406, M point inverse discrete Fourier transform (IDFT) module 408, cyclic prefix (CP) add module 410, parallel / series transform. Includes device 412 and RF / Digital-to-Analog Converter (DAC) module 414.

Signal processing in the OFDMA transmitter proceeds as follows. First, the bitstream is modulated into a data symbol sequence. The bitstream is obtained by performing various signal processing such as channel coding, interleaving, scrambling, etc. on the data block distributed from the MAC layer. A bitstream, also called a codeword, is equivalent to a block of data received from the MAC layer. Data blocks received from the MAC hierarchy are transport blocks. Also called block). Modulation schemes can include, but are not limited to, two-phase shift keying (BPSK), four-phase shift keying (QPSK), and n quadrature amplitude modulation (n-QAM). The series of data symbol sequences are then converted in parallel by N (402). N data symbols are mapped to the assigned N subcarriers out of a total of M subcarriers, and the remaining MN carriers are zero-packed (406). The data symbols mapped to the frequency domain are converted into a time domain sequence by the M point IDFT process (408). Then, in order to reduce intersymbol interference (ISI) and intercarrier interference (ICI), CP is added to the time domain sequence to generate an OFDMA symbol (410). The generated OFDMA symbols are converted from parallel to serial (412). The OFDMA symbol is then transmitted to the receiver through processes such as digital-to-analog conversion and frequency upward conversion (414). Other users are assigned the available subcarriers out of the remaining MN subcarriers. On the other hand, the OFDMA receivers are RF / analog-to-digital conversion (ADC) module 416, series / parallel converter 418, CP removal module 420, M point DFT module 422, subcarrier demapping / equalization module 424, parallel / series conversion. Includes instrument 428 and detection module 430. The signal processing of the OFDMA receiver has the reverse configuration of the OFDMA transmitter.

The SC-FDMA transmitter, on the other hand, further includes an N-point DFT module 404 before the subcarrier mapping module 406 as compared to the OFDM transmitter. The SC-FDMA transmitter significantly reduces the peak-to-average power ratio (PAPR) of the transmitted signal compared to the OFDM method by spreading multiple data over the frequency domain using DFT before IDFT processing. can do. The SC-FDMA receiver further includes an N-point IDFT module 426 after the subcarrier demapping module 424 as compared to the OFDM receiver. The signal processing of the SC-FDMA receiver has the opposite configuration to that of the SC-FDMA transmitter.

FIG. 4 is a diagram showing the structure of a radio frame used in LTE.

Refer to Fig. 4, the wireless frame is 10ms (327200 T)._s), And consists of 10 subframes of the same size. Each subframe has a length of 1 ms and is composed of two slots. Each slot is 0.5ms (15360 T)_s) Has a length. T_sRepresents the sampling time, T_s= 1 / (15kHz x 2048) = 3.2552 x 10^-8It is represented by (about 33ns). Slots contain multiple OFDM symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. In an LTE system, one resource block contains 12 subcarriers x 7 (6) OFDM symbols. The transmission time interval (TTI), which is the unit time for data transmission, can be determined in units of one or more subframes. The structure of the radio frame described above is merely an example, and the number of subframes, the number of slots, and the number of OFDM symbols included in the radio frame may be changed in various ways.

FIG. 5 is a diagram showing an example of communication in a single component carrier wave environment. Figure 5 corresponds to a communication example in an LTE system.

Referring to FIG. 5, in the frequency division duplex (FDD) system, communication is generally performed through one downlink band and one corresponding uplink band. Further, in the time division duplex (TDD) system, communication is performed through the downlink section and the corresponding uplink section. In the FDD system or the TDD system, data and / or control information can be transmitted / received in subframe units. The terminal uses the power control method to increase the power for transmission when the channel environment is not good, and lower the power for transmission when the channel environment is good. Optimize power usage by reducing interference with. If the channel environment is not good, the base station will instruct the terminal to increase its power, but the terminal's maximum transmit power (ie, transmit power limit; P.^UE_MaxOr P_Max) Is ignored.

FIG. 6A is a diagram showing the structure of the uplink subframe used in LTE.

Referring to FIG. 6A, the uplink subframe contains multiple (eg, 2) slots. Slots can contain a different number of SC-FDMA symbols depending on the CP length. As an example, for normal CP, the slot can contain 7 SC-FDMA symbols. Uplink subframes are divided into a data area and a control area. The data area includes a physical upling shared channel (PUSCH) and is used to transmit data signals such as audio and video. The power of the data signal is determined based on the power of the reference signal included in the same area. As an example, the power of the data signal may be determined based on the power of the demodulation reference signal (DMRS).

The control area includes a physical uplink control channel (PUCCH) and transmits various control information on the uplink. PUCCH contains RB pairs located at both ends of the data region on the frequency axis and hops at the slot boundary. The transmission power of the control information is determined based on the transmission power of the control channel reference signal located on the PUCCH. Details of the PUCCH structure will be described later with reference to FIG. 6B. The measurement reference signal (SRS) for uplink channel measurement is located at the last SC-FDMA symbol of the subframe and is transmitted through all or part of the band of the data area.

In the LTE system, the feature of uplink transmission is the single carrier characteristic using SC-FDMA, and PUSCH, PUCCH, and SRS are not allowed to be transmitted at the same time. SC-FDMA enables efficient use of power amplifiers by maintaining low PAPR compared to multiple carrier systems (eg OFDM). Therefore, when the data and the control signal are transmitted at the same time, the information to be transmitted by the PUCCH is multiplexed with the data in the PUSCH area by the piggyback method. Also, PUSCH or PUCCH is not transmitted to the SC-FDMA symbol to which SRS is transmitted. The power control of PUSCH and PUCCH is performed independently.

Figure 6B illustrates the PUCCH structure used in LTE.

Referring to FIG. 6B, in the case of a regular CP, the reference signal (UL RS) is carried by three consecutive symbols located in the middle of the slot, and the control information (that is, acknowledgment) is carried by the remaining four symbols. Responses and negative responses (ACK / NACK)) are carried. For extended CP, the slot contains 6 symbols and the 3rd and 4th symbols carry the reference signal. Control information further includes channel quality information (CQI), schedule request (SR), precoding matrix index (PMI), rank indicator (RI), and the like. The transmission power of the control information is determined based on the transmission power of the reference signal (UL RS). The PUCCH structure is UL depending on the type of control information. The number and position of RS are different. Resources for control information use separate cyclic shifts (CS) (frequency spread) and / or separate Walsh / DFT orthogonal signs (time spread) of computer-generated constant amplitude zero autocorrelation (CG-CAZAC) sequences. It is classified. W0, w1, w2, w3 that are multiplied after the IFFT have the same result even if they are multiplied before the IFFT. The reference signal may be multiplied by an orthogonal cover (OC) sequence of the appropriate length.

Figure 7 shows an example of communication under a multi-component carrier environment. Recently, wireless communication systems (eg, LTE-A systems) are carriers that use a larger uplink / downlink bandwidth by bundling multiple uplink / downlink frequency blocks to use a wider frequency band. Use carrier aggregation, or bandwidth aggregation technology. Each frequency block is transmitted using a component carrier (CC). In the present specification, the component carrier may mean a frequency block for carrier aggregation or a central carrier of a frequency block, depending on the context, and these may be mixed with each other.

With reference to Figure 7, five 20MHz CCs can be bundled on each uplink / downlink to support 100MHz bandwidth. The CCs may or may not be adjacent to each other in the frequency domain. FIG. 7 shows a case where the bandwidth of the uplink component carrier wave and the bandwidth of the downlink component carrier wave are both the same and symmetrical for convenience. However, the bandwidth of each component carrier may be determined independently. As an example, the bandwidth of the uplink component carrier is 5MHz (A)._UL) + 20MHz (B_UL) + 20MHz (C_UL) + 20MHz (D_UL) + 5MHz (E_UL) May be configured. It is also possible to perform asymmetric carrier aggregation in which the number of uplink component carriers and the number of downlink component carriers are different. Asymmetric carrier aggregation can occur due to restrictions on the available frequency bands or can be artificially done by network settings. As an example, even if the entire system band is composed of N CCs, the receivable frequency band of a specific terminal may be limited to M (&lt;N) CCs. Various parameters related to carrier wave aggregation may be set by cell identification, terminal group identification, or terminal identification method.

In LTE-A systems, the transmitting end can transmit multiple signal / (physical) channels simultaneously through a single or multiple CC. As an example, two or more identical or distinct channels selected from PUSCH, PUCCH or SRS can be transmitted simultaneously. Therefore, when transmitting multiple (physical) channels without maintaining the single carrier transmission characteristics, the terminal when the sum of the transmitted powers calculated for the multiple (physical) channels reaches the maximum transmission power limit. It is necessary to consider the operation of. Unless otherwise specified herein, a plurality of signal / (physical) channels means signal / (physical) channels in which transmission power is independently determined. As an example, a plurality of signal / (physical) channels include signal / (physical) channels associated with reference signals that are separate from each other. As used herein, transmitting a (physical) channel means transmitting a signal through the (physical) channel. As used herein, signals and (physical) channels are used together. Hereinafter, a method of controlling the transmission power will be specifically described with reference to FIGS. 8 to 11. For convenience, FIGS. 8 to 11 have been described from the standpoint of the terminal, but this is an example, and even when the base station transmits a plurality of signals, it can be easily applied by modifying it. In the embodiment according to the present invention, the transmission power can be expressed on a linear scale or a dB scale. Further, the operation according to the embodiment of the present invention may be executed in the power region or the amplitude region.

<u style="single">Example 1: Power control considering (channel) priority</u> FIG. 8 is a diagram showing an example of adjusting the transmission power according to the embodiment of the present invention. This embodiment proposes to adjust the transmission power of a physical channel in consideration of the (channel) priority when the sum of the transmission powers of a plurality of physical channels exceeds the maximum transmission power.

Referring to FIG. 8, the terminal can receive one or more transmit power control (TPC) instructions from the base station (S810). The TPC instruction may be included in the response message to the preamble for random access or may be transmitted through the PDCCH. There are various formats for PDCCH depending on the downlink control information (DCI), and the TPC instruction to be transmitted may differ depending on the format. For example, the terminal can receive PDCCH in various formats such as a format for a downlink schedule, a format for an uplink schedule, a TPC-dedicated format for PUSCH, and a TPC-dedicated format for PUCCH. The TPC instruction can also be used to determine the transmit power for each component carrier, the transmit power for a component carrier group, or the transmit power for the entire component carrier. The TPC instruction can also be used to determine the transmit power for each signal (eg PUSCH, PUCCH, etc.). TPC instructions include formats for downlink schedules, formats for uplink schedules, TPC-only formats for uplink data channels (eg PUSCH), TPC-only formats for uplink control channels (eg PUCCH), etc. It can be received through PDCCH in various formats.

If the terminal has multiple physical channels scheduled to be transmitted to the base station at the same time, the transmission power to the multiple uplink physical channels (P1, P2, ..., P)_N; N 2) is determined individually (S820). Each uplink physical channel contains one or more consecutive OFDMA symbols or SC-FDMA symbols. An example in which a terminal transmits a plurality of signals by uplink is shown in FIG. 9, but the present invention is not limited to this. With reference to FIG. 9, multiple physical channels can be transmitted simultaneously using a single component carrier or multiple component carriers. For example, a plurality of PUCCHs, a plurality of PUSCHs or a plurality of SRSs may be transmitted at the same time (cases 1 to 3), or a combination of PUCCHs, PUSCHs and / or SRSs may be transmitted at the same time (cases 4 to 7). .. In the case of PUCCH, detailed classification is possible, such as when transmitting ACK / NACK, CQI, SR.

Once the uplink transmit power is determined, the terminal sums up the transmit power of the uplink physical channels (ΣP)._n; 1 n N) is the maximum power value (P)_Max) Is greater than (S830). The maximum power value can be given in CC, CC group or whole CC unit. The maximum power value basically depends on the physical capacity of the terminal, but can be predetermined for each communication system. Further, the maximum power value can be changed in consideration of the allowable power in the cell, the load balance, and the like. Therefore, in the present specification, the maximum power value is mixed with the maximum available power value and can be replaced with each other. Information about the maximum power value may be broadcast in the cell through a broadcast message (eg, system information) or may be notified via an RRC message. In addition, information about the maximum power value can be transmitted to the terminal through a downlink control channel (eg, PDCCH). The maximum power value can be set permanently, semi-permanently or dynamically depending on the channel environment. If the maximum power value is limited by the notification of the base station, the maximum power value can have the same meaning as the allowable power value in the cell. For example, the maximum power value may be predetermined, or may be specified by a cell identification method, a terminal group identification method, a terminal identification method, a CC group identification method, or a CC identification method.

Sum of transmit power of uplink physical channels (ΣP)_n; 1 n N) is the maximum power value (P)_Max) In the following cases, the transmission power for the corresponding uplink physical channel is maintained as it is. On the other hand, when the sum of the transmission powers of the uplink physical channels is larger than the maximum transmission power value, one so that the sum of the transmission powers of the uplink physical channels does not exceed the maximum power value in consideration of the priority. Adjust the transmission power of the above uplink physical channels (S840). The priority can be determined by considering the type of uplink physical channel and the information on the uplink physical channel. The details of the priority will be described later. The transmission power may be adjusted for the entire band, or in CC group units or CC units.

When the transmit power for the uplink physical channel is adjusted, the terminal generates multiple uplink physical channels with the corresponding transmit power (S850). Control of transmit power over the uplink physical channel can, but is not limited to, in the frequency domain prior to IFFT (408 in Figure 3). In this case, the transmission power can be controlled in units of subcarriers, for example, by multiplying the modulation value mapped to the subcarrier by a weighted value. The weighted values may be multiplied using a diagonal matrix (power diagonal matrix) in which each element represents a value associated with the transmitted power. For multi-input, multi-output (MIMO) systems, the transmit power may be controlled using a precoding matrix that reflects the weighted values, or the precoded modulation values are controlled by multiplying the power diagonal matrix. You may. Therefore, even when a plurality of physical channels are included in the frequency band to which the same IFFT is applied, the transmission power of each physical channel can be easily controlled. Also, the transmission power control for the uplink physical channel may be performed in the time domain after the IFFT, with or separately from the power control in the frequency domain. Specifically, the transmission power control in the time domain can be performed by various functional blocks. As an example, transmission power control may be performed by a DAC block and / or an RF block (414 in FIG. 3). The terminal then transmits the generated multiple uplink physical channels to the base station through one or more CCs (S860). As used herein, simultaneous or identical periods include the same TTI or subframe.

In step S840 of FIG. 8, a method of adjusting the transmission power of the uplink channel in consideration of the priority will be specifically described. For convenience, the equivalent order or priority when only two channels exist will be described. However, the present invention is also applicable to three or more homologous, heterogeneous, or homologous and heterogeneous channel combinations.

For convenience of explanation, the symbols are defined as follows.

P_PUSCH: Represents the power calculated to be allocated to PUSCH. Due to power restrictions, the actual power allocated may be less than this. If there is no dB display, it means a linear scale.

P_PUCCH: Represents the power calculated to be allocated to PUCCH. Due to power restrictions, the actual power allocated may be less than this. If there is no dB display, it means a linear scale.

P_SRS: Represents the power calculated to be allocated to SRS. Due to power restrictions, the actual power allocated may be less than this. If there is no dB display, it means a linear scale.

<u style="single">Case 1-1: P</u>_{<u style="single">PUSCH</u>}<u style="single">+ P</u>_{<u style="single">PUSCH</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Case 1-1 is a case where the maximum power limit is reached when a plurality of PUSCHs are transmitted simultaneously in a plurality of separate CCs. In this case, the transmission power of each PUSCH can be reduced or dropped. Specifically, the following options can be considered.

Option 1: The same priority can be given between PUSCHs. When the priorities are the same, the power of the entire PUSCH can be reduced by the same rate or by the same amount. That is, the same attenuation ratio can be applied or the same value can be subtracted.

Option 2: Prioritize between PUSCHs, taking into account the transmission format on PUSCHs. For example, prioritize according to Transport Block Size (TBS) or modulation coding method (MCS), and sequentially reduce or drop transmission power from PUSCH with lower priority. Preferably, the priority is set low for PUSCH with a small TBS (data volume), low MCS (low code rate) or low modulation order. In this case, a higher attenuation ratio can be applied to the lower priority PUSCH. However, if the transmission power is exceeded even though only one PUSCH remains due to the PUSCH drop, the power of the PUSCH is changed to P._MaxReduce to and send.

<u style="single">Case 1-2: P</u>_{<u style="single">PUCCH</u>}<u style="single">(ACK / NACK) + P</u>_{<u style="single">PUSCH</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Case 1-2 is a case where the sum of the transmission powers of PUCCH and PUSCH that transmit ACK / NACK reaches the maximum power limit in different CCs or one CC. The following options can be considered.

Option 1: ACK / NACK can be prioritized. UL ACK / NACK reports whether DL data has been successfully received, and if this report is not made properly, DL resources will be wasted. Therefore, high priority is given to the transmission of ACK / NACK, and the transmission power of PUSCH is reduced to transmit or drop. When reducing the transmission power of the PUSCH, the transmission power may be allocated to the PUCCH first, and the remaining power may be allocated to the PUSCH. This can be expressed by the following formula. P_PUSCH= P_max-P_{PUCCH (ACK / NACK)}In this case, the following method can be further applied.

Option 1.1: PUSCH error rate increases because only the remaining power allocated to PUCCH is used for PUSCH. Therefore, the MCS of the data transmitted to the PUSCH is reduced and transmitted so that the PUSCH can be received with the same error rate as before the power was reduced. Therefore, the reduced MCS information may be notified to the base station.

Option 2: PUSCH can be prioritized. When reducing the power of the PUCCH that sends ACK / NACK, DL resource waste occurs due to UL ACK / NACK reception error. In particular, when NACK is recognized as ACK, re-transmission of the upper layer occurs, and the transmission delay of DL data increases. On the other hand, when ACK is recognized as NACK, only waste of retransmission in the physical layer occurs. Therefore, when transmitting urgent data, in case data delay occurs due to sustained low power PUSCH transmission, power is first allocated to PUSCH, and the remaining power (reduced power) is used for PUCCH transmission. You can consider allocating. In this case, the power reduction of PUCCH is preferably limited to the case of ACK.

<u style="single">Case 1-3: P</u>_{<u style="single">SRS</u>}<u style="single">+ P</u>_{<u style="single">PUSCH</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Case 1-3 is a case where the sum of the transmission powers of SRS and PUSCH reaches the maximum power limit in different CCs or one CC. The following options can be considered.

Option 1: You can prioritize SRS transmissions. SRS is used by base stations to measure UL channel status for optimal UL scheduling. Focusing on the efficiency of subsequent schedules, prioritize SRS and reduce the transmission power of PUSCH to transmit or drop. When reducing the transmission power of the PUSCH, the transmission power may be allocated to the SRS first, and the remaining power may be allocated to the PUSCH. This can be expressed by the following formula. P_PUSCH= P_Max-P_SRS In this case, the following method can be further applied.

Option 1.1: PUSCH error rate increases because only the remaining power allocated to SRS is used for PUSCH. Therefore, the MCS of the data transmitted to the PUSCH is reduced and transmitted so that the PUSCH can be received with the same error rate as before the power was reduced. For this purpose, the reduced MCS information may be notified to the base station.

Option 2: You can prioritize PUSCH transmissions. When transmitting with the SRS transmission power reduced, the base station does not know whether the received power has dropped due to the bad UL radio channel environment condition or the terminal has reduced the power for transmission, so the channel information is misjudged. May be done. Therefore, if the transmission power is insufficient, SRS may be dropped.

<u style="single">Case 1-4: P</u>_{<u style="single">PUCCH (ACK / NACK)</u>}<u style="single">+ P</u>_{<u style="single">PUCCH (ACK / NACK)</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Case 1-4 is a case where the sum of the transmission powers of a plurality of PUCCHs that transmit ACK / NACK reaches the maximum power limit. Reduce or drop the transmit power of each PUCCH. Specifically, the following options can be considered.

Option 1: PUCCHs that send ACK / NACK can have the same priority. If the priorities are the same, the PUCCH power is reduced by the same rate or by the same amount. That is, the same attenuation ratio may be applied or the same value may be subtracted.

Option 2: Prioritize and reduce or drop some PUCCH power.

Option 2.1: Misidentifying NACK as ACK results in more resource waste and delay than misidentifying ACK as NACK. Therefore, the transmission power of the PUCCH that transmits the ACK is preferentially reduced or dropped. It can also be considered to set a specific threshold and reduce the power to the threshold.

Option 2.2: Prioritize PUCCH based on PDSCH TBS or MCS corresponding to PUCCH ACK / NACK, and preferentially reduce or drop the transmission power of lower priority PUCCH. Preferably, the PDSCH of small TBS or low MCS is set low in priority. However, when dropping a PUCCH, if the transmission power is exceeded even though only one PUCCH remains, the power of the PUCCH is changed to P._maxReduce to and send.

<u style="single">Case 1-5: P</u>_{<u style="single">PUCCH (CQI)</u>}<u style="single">+ P</u>_{<u style="single">PUCCH (CQI)</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Cases 1-5 are cases in which the sum of the transmission powers of a plurality of PUCCHs transmitting CQI reaches the maximum power limit in different CCs. The CQI value allows you to grasp the status of the DL radio channel and perform an efficient DL schedule. The following options can be considered.

Option 1: PUCCH sending CQI can have the same priority. If the priorities are the same, the power of the entire PUCCH can be reduced by the same rate or by the same amount. That is, the same attenuation ratio may be applied or the same value may be subtracted.

Option 2: Prioritize and reduce or drop some PUCCH power. The base station selects a radio channel with a high CQI and schedules it to the terminal. Channels with low CQI are less likely to be selected by the base station, so accurate reception is less important. Therefore, at the time of transmission, the transmission power of PUCCH having a low CQI value is preferentially reduced or dropped. It can also be considered to set a specific threshold and reduce it to the threshold.

<u style="single">Case 1-6: P</u>_{<u style="single">PUCCH (ACK / NACK)</u>}<u style="single">+ P</u>_{<u style="single">PUCCH (CQI)</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Cases 1-6 are cases where the sum of the transmission powers of a plurality of PUCCHs that transmit CQI and ACK / NACK reaches the maximum power limit. As mentioned above, ACK / NACK has a high priority. CQI, on the other hand, is information that transmits the status of the DL channel to the base station and is used for an effective DL schedule. Even if a better channel is assigned to the terminal, if the normal reception of data cannot be confirmed accurately, unnecessary retransmissions will occur, and therefore CQI has a low priority. Therefore, power is preferentially allocated to the PUCCH that transmits ACK / NACK, and the remaining power is allocated to the PUCCH that transmits CQI, or the PUCCH that transmits CQI is dropped. On the other hand, PUSCH that transmits both CQI and ACK / NACK is treated in the same way as PUCCH that transmits ACK / NACK.

<u style="single">Case 1-7: P</u>_{<u style="single">PUCCH (SR)</u>}<u style="single">+ P</u>_{<u style="single">PUCCH (ACK / NACK)</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Cases 1-7 are cases where the sum of the transmission powers of a plurality of PUCCHs that transmit SR and ACK / NACK reaches the maximum power limit. The following options can be considered.

Option 1: High priority can be given to ACK / NACK transmissions. Therefore, power is first allocated to the PUCCH to which the ACK / NACK is transmitted, and the remaining power is allocated to the PUCCH to which the SR is transmitted, or the PUCCH to which the SR is transmitted is dropped. On the other hand, if ACK / NACK exists for a long time and PUCCH that sends SR is dropped, UL cannot be scheduled. To compensate for this, if the SR is delayed for a certain amount of time, the PUCCH that sends the ACK / NACK may be dropped.

Option 2: High priority can be given to SR transmission. Since the ACK / NACK error is eliminated by retransmission, the SR is prioritized with an emphasis on the schedule, and the transmission power of the PUCCH to which the ACK / NACK is transmitted is reduced and transmitted or dropped. When reducing the transmission power of the PUCCH, the transmission power may be allocated to the SR first, and the remaining power may be allocated to the PUCCH. This can be expressed by the following formula. P_{PUCCH (ACK / NACK)}= P_Max-P_SR

Option 3: The terminal sends ACK / NACK on PUCCH where SR is sent. In this case, the base station can detect the binary amplitude-modulated (On / Off Keying) SR from the PUCCH by energy detection, and can determine ACK / NACK by decoding the symbol. At this time, when there are a plurality of PUCCHs for transmitting ACK / NACK, the ACK / NACK bundle or PUCCH selective transmission can be used. The ACK / NACK bundle sends all ACKs when multiple DL PDSCHs are received without error, and sends one NACK when any one of the DL PDSCHs is incorrect. PUCCH selective transmission represents the result of a plurality of ACK / NACKs by transmitting a modulation value through one PUCCH resource selected from a plurality of occupied PUCCH resources when a plurality of DL PDSCHs are received.

<u style="single">Case 1-8: P</u>_{<u style="single">PUSCH (UCI)</u>}<u style="single">+ P</u>_{<u style="single">PUSCH</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Case 1-8 is a case where the sum of the transmission powers of PUSCH that transmits uplink control information (UCI) and PUCCH that transmits only data reaches the maximum power limit in separate CCs. You can consider the following options:

Option 1: Do not consider UCI and follow the prioritization method illustrated in Case 1-1. For example, PUSCH can be given the same priority. In this case, the power of PUSCH can be reduced by the same rate. Also, the PUSCH may be assigned a separate priority in consideration of the transmission format on the PUSCH.

Option 2: The UCI-piggybacked PUSCH contains control information so that UCI-piggybacked channels can be prioritized. Therefore, the transmission power of PUSCH, which carries only data, is reduced and transmitted or dropped. To reduce the transmit power of the PUSCH that carries only the data, the UCI may first allocate the transmit power to the piggybacked PUSCH and then allocate the remaining power to the PUSCH that carries only the data. This can be expressed by the following formula. P_PUSCH= P_Max-P_{PUCCH (UCI)} Further, when reducing the transmission power of the PUSCH that carries only data, a larger attenuation ratio may be applied to the PUSCH that carries only data. However, if the PUCCH drop exceeds the transmission power even though only one PUSCH remains, P the power of that PUSCH._MaxReduce to and send.

<u style="single">Case 1-9: P</u>_{<u style="single">PUSCH (Retransmission)</u>}<u style="single">+ P</u>_{<u style="single">PUSCH</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Case 1-9 is a case where the sum of the transmission powers of the PUSCH carrying the retransmission data and the PUSCH carrying the new data reaches the maximum power limit.

Option 1: Follow the prioritization method illustrated in Case 1-1 without considering retransmissions. For example, PUSCH can be given the same priority. In this case, the power of PUSCH can be reduced by the same rate. Also, the PUSCH may be assigned a separate priority in consideration of the transmission format on the PUSCH.

Option 2: Retransmission may be due to a decrease in transmit power during the preceding transmission, so higher priority of the PUSCH to be retransmitted can improve the PUSCH reception rate.

Cases 1-10: P_{PUSCH (Retransmission)}+ P_{PUSCH (Retransmission)}&gt; P_Max

Cases 1-10 are cases where the sum of the transmission powers of the PUSCHs that carry the retransmission data reaches the maximum power limit. You can consider the following options:

Option 1: Follow the prioritization method illustrated in Case 1-1 without considering retransmissions. For example, PUSCH can be given the same priority. In this case, the power of PUSCH can be reduced by the same rate. Also, the PUSCH may be assigned a separate priority in consideration of the transmission format on the PUSCH.

Option 2: Retransmits can result from reduced transmit power during the preceding transmit, so PUSCHs with more retransmissions are given higher priority and receive more retransmitted PUSCHs. Improve the rate further.

<u style="single">Case 1-11: P</u>_{<u style="single">PUSCH (Retransmission)</u>}<u style="single">+ P</u>_{<u style="single">PUCCH</u>}<u style="single">/ P</u>_{<u style="single">SRS</u>}<u style="single">&gt; P</u>_{<u style="single">Max</u>} Cases 1-11 are cases where the sum of the transmission powers of PUSCH and PUCCH / SRS that carry the retransmission data reaches the maximum power limit. You can consider the following options:

Option 1: The prioritization methods illustrated in Cases 1-2 and 1-3 can be followed without considering retransmissions.

Option 2: Retransmission may result from a reduction in transmit power during the preceding transmission, so the PUSCH being retransmitted can be prioritized and the reception rate of that PUSCH can be improved.

<u style="single">Example 2: Power control by CC (group)</u> The terminal transmission power control method described above is suitable for a power control method when the terminal has one power amplifier. However, in LTE-A, a plurality of CCs may be assigned to the terminal, and these assigned CCs may be continuous bands on the frequency axis or may be separate bands. When the allocated CCs exist as separate bands, the terminal may require multiple power amplifiers because it is difficult to amplify power in a wide frequency domain with just one power amplifier. In this case, each power amplifier may be responsible for power amplification of only one CC or only a CC group composed of several CCs. Therefore, by extending the method proposed above to the power control method for each CC or CC group, it can be naturally applied even in a situation where the terminal has a large number of power amplifiers.

In the following, in an environment where both the transmission power limit by CC (group) and the total transmission power limit of the terminal exist, the terminal reaches the transmission power limit of a specific CC (group), reaches the terminal total transmission power limit, Alternatively, the terminal operation according to the embodiment of the present invention when both power limits are reached at the same time will be described.

In general, the uplink transmission power of the terminal can be limited as in Equation 1.

(Equation 1)<maths num="1"><img file="JP5508563B2_D0001.tif" /></maths>

When the quantization level of the power amplifier of the terminal is sufficiently high, the equal sign may hold in the above inequality as in Equation 2.

(Equation 2)<maths num="2"><img file="JP5508563B2_D0002.tif" /></maths>

The symbols used in the above equation are defined as follows.

P^UE: Indicates the uplink transmission power of the terminal.

P^UE_Max(P_Max): Indicates the maximum transmission power value (or transmission power limit value) of the terminal. That is, it represents the maximum transmission power (or transmission power limit value) of the terminal with respect to the entire CC. The maximum transmission power value of the terminal may be determined by the total transmittable power of the terminal, or may be determined in combination with the value set in the communication network (eg, base station). Further, the information regarding the maximum transmission power value of the terminal may be instructed by the notification of the upper layer. For example, the information regarding the maximum transmission power value of the terminal may be notified by the cell identification method through the broadcast message, or may be notified by the terminal identification method or the terminal group identification method through the RRC message.

P^{CC = i}_Max: Indicates the maximum transmission power value (or transmission power limit value) in the i-th CC (group). The maximum transmission power value for each CC (group) may be determined by the total transmittable power of the terminal or the transmittable power for each CC (group), or set for each CC (group) in the communication network (eg, base station). It may be determined in combination with the specified value. Further, the information on the maximum transmission power value for each CC (group) may be instructed by the notification of the upper layer. For example, information on the maximum transmission power value for each CC (group) may be notified by a cell identification method through a broadcast message, or may be notified by a terminal identification method or a terminal group identification method through an RRC message. On the other hand, the maximum transmission power value for each CC (group) may be notified in consideration of interference information (or coverage) with other terminals (or CC (group)). In this case, the information regarding the maximum transmission power value for each CC (group) can include information regarding interference (or coverage) with another terminal (or CC (group)). The maximum transmission power for each CC (group) can have the same value in any CC (group).

P^{CC = i}_{Ch = j}: Represents the transmission power of the j-th channel of the i-th CC (group).

<u style="single">Case 2-1:</u><maths num="3"><img file="JP5508563B2_D0003.tif" /></maths> In Case 2-1 the sum of the maximum transmission powers of the CCs (groups) is smaller than the maximum transmission power of the terminals in any CC (group), and at the same time, the sum of the transmission powers of the channels in all CCs (groups) is the terminal. This is a case that is smaller than the maximum transmission power of. Since the transmission power of the terminal is not limited to the total transmission power value, it can be simplified as in Equation 3.

(Equation 3)<maths num="4"><img file="JP5508563B2_D0004.tif" /></maths>

When the quantization level of the power amplifier of the terminal is sufficiently high, the equal sign may hold in the above inequality as in Equation 4.

(Equation 4)<maths num="5"><img file="JP5508563B2_D0005.tif" /></maths>

In equations 3 and 4, the set S means a CC (group) set in which the sum of the transmission powers of the channels exceeds the maximum transmission power value of the CC (group) in the CC (group). For example<maths num="6"><img file="JP5508563B2_D0006.tif" /></maths> In this case, the sum of the channel transmission powers is adjusted so as not to exceed the CC (group) maximum transmission power value only within the set S. Power control can be performed by introducing an attenuation coefficient. For example, the power control is set to the attenuation coefficient α for the transmission power of each channel as shown in Equation 5.ⁱ_j(0 αⁱ_jIt can be simplified to the method of searching for 1).

(Equation 5)<maths num="7"><img file="JP5508563B2_D0007.tif" /></maths>

<u style="single">Case 2-2:</u><maths num="8"><img file="JP5508563B2_D0008.tif" /></maths> Case 2-2 is a case where the maximum transmission power of the terminal is smaller than the sum of the maximum transmission powers of CCs (groups) and at the same time smaller than the sum of the transmission powers of all channels. Since the transmission power of the terminal is limited to the maximum transmission power value, it is expressed by Equation 6.

(Equation 6) P^UE P^UE_Max

When the quantization level of the power amplifier of the terminal is sufficiently high, the equal sign may hold in the above inequality as in Equation 7.

(Equation 7) P^UE= P^UE_Max

In this case, as in Case 2-1 the transmission power of the terminal can be reduced to the maximum transmission power value of the terminal. In this case, the sum of the transmission powers of each channel in each CC (group) must be smaller than the maximum transmission power value of the CC (group), and the sum of the transmission powers of all CCs (groups). Must be less than the terminal's maximum transmit power value. Power control has an attenuation coefficient α for the transmission power of each channel, as shown in Equation 8.ⁱ_j(0 αⁱ_jIt can be simplified to the method of searching for 1).

(Equation 8)<maths num="9"><img file="JP5508563B2_D0009.tif" /></maths>

The method illustrated in Cases 2-1 and 2-2 finds the attenuation coefficient through optimization for two limits (total transmit power limit, CC (group) transmit power limit), which makes the optimization a little more complicated. There can be a problem. Therefore, a method for efficiently calculating the damping coefficient will be illustrated with reference to FIGS. 10 and 11.

In FIGS. 10 and 11, the horizontal axis represents CC (group) and the vertical axis represents power intensity. The hatched boxes in each CC (group) represent the channels within that CC (group). The hatches are multiplied for convenience to represent the channels, and each hatch may mean a separate channel or the same channel. Further, in FIGS. 10 and 11, the sum of the transmission powers of the CCs (groups) is larger than the maximum transmission power value (P_UE_MAX) of the terminal, and the sum of the transmission powers of the channels in the CCs (groups) 1 and 3 is the sum of the transmission powers of the channels. It is assumed that the maximum transmission power (P_CC1_MAX and P_CC3_MAX) of CC (group) is exceeded ((a) in FIG. 10 and (a) in FIG. 11). CCs (groups) 1 and 3 constitute the set S described in equations 3 and 4.

FIG. 10 illustrates a method of obtaining an attenuation coefficient for power control according to an embodiment of the present invention. With reference to FIG. 10, the attenuation coefficient for power control is obtained in two steps. The first step is to attenuate the transmit power of the channels in the set S in order to meet the transmit power limit criteria of the CC (group). In the first stage, the damping coefficient αⁱ_jMay be determined independently according to the conditions of Equation 9.

(Equation 9)<maths num="10"><img file="JP5508563B2_D0010.tif" /></maths>

With reference to (b) of FIG. 10, it can be seen that the sum of the transmission powers of the channels in CC (group) 1 and 3 is reduced to the maximum transmission power value of the corresponding CC (group).

However, in (b) of FIG. 10, the sum of the transmission powers of CC (group) is still larger than the maximum transmission power value (P_UE_MAX) of the terminal. In this way, when the transmission power of the channels belonging to the set S is reduced but the total transmission power limit of the terminal is still not satisfied, the second step is to reduce all the channels of the entire CC (group). The transmission power of the terminal can be reduced to match the total transmission power limit of the terminal. In the second stage, the damping coefficient βⁱ_jMay be determined independently according to the conditions of Equation 10.

(Equation 10)<maths num="11"><img file="JP5508563B2_D0011.tif" /></maths>

With reference to (c) in FIG. 10, it can be seen that the sum of the transmission powers of all channels has been reduced to the total transmission power limit value (P_UE_MAX) of the terminal. For simplicity, β of the channel in set Sⁱ_jSet to 1 and β only for the coset of Sⁱ_jMay be determined. Alternatively, β of the channel in the coset of Sⁱ_jSet to 1 and β for S onlyⁱ_jMay be determined.

FIG. 11 illustrates a method of determining the damping coefficient according to another embodiment of the present invention. With reference to FIG. 11, the damping coefficient for power control is basically determined in two steps and can further include one step for power compensation. In the first stage, the transmit power of the channel in all CCs (groups) may be attenuated to meet the total transmit power limit criteria of the terminal. Attenuation coefficient βⁱ_jMay be determined independently according to the conditions of Equation 11.

(Equation 11)<maths num="12"><img file="JP5508563B2_D0012.tif" /></maths>

Referring to (b) in FIG. 11, the channel transmit power is reduced in all CCs (groups) so that the sum of the transmit powers of all channels matches the terminal's total transmit power limit (P_UE_MAX). You can see that.

However, in FIG. 11 (b), the sum of the transmit powers of the CC (group) 3 channels is still greater than the CC (group) 3 power limit (P_CC3_MAX). Thus, when there are CCs (groups) (ie, sets S) that have reduced the channel's transmit power in all CCs (groups) but still cannot meet the transmit power limits in the CCs (groups). , As a second step, the transmit power of all CC (group) channels in the set S may be reduced. Attenuation coefficient αⁱ_jMay be determined independently according to the conditions of Equation 12.

(Equation 12)<maths num="13"><img file="JP5508563B2_D0013.tif" /></maths>

Referring to (c) of FIG. 11, the sum of the transmission powers of the channels of CC (group) 3 (that is, set S) is reduced according to the maximum transmission power value (P_CC3_MAX) of the corresponding CC (group). I understand.

Then, as a third step, the amount of power reduced from the channel of set S<maths num="14"><img file="JP5508563B2_D0014.tif" /></maths>May be compensated for in the channels in the coset of S. Here, it is desirable that the compensated power of each channel does not exceed the maximum transmission power value in the corresponding CC (group). With reference to (d) in FIG. 11, it can be seen that the power reduced from CC (group) 3 in the second stage was compensated by CC (group) 2. Contrary to (d) in FIG. 11, the power reduced from CC (group) 3 in the second stage may be compensated to CC (group) 1. The following can be considered as the power compensation method.

(1) Priority Criteria: Priority is assigned to each channel based on the urgency or importance of the message in the channel (PUCCH, PUSCH, SRS), and the channel with the higher priority is compensated for more power. (2) Same compensation amount: Compensation is performed with the same power for all channels in the residual set of S. (3) Same compensation rate: Compensation is performed at the same rate for all channels in the co-set of S. (4) Compensate for power using possible combinations of (1), (2) and (3).

Attenuation coefficient (α) described with reference to FIGS. 10 and 11.ⁱ_j, βⁱ_j) Can be determined in various ways. Not limited to this, but the damping coefficient (α)ⁱ_j, βⁱ_j) Can be considered as a criterion for determining the priority, the same amount of attenuation, the same attenuation factor, or a combination thereof.

The priority-based method assigns a priority to each channel based on the urgency or importance of the message on the channel (eg PUCCH, PUSCH, SRS) and applies the higher attenuation factor in the order of higher priority channels. That is, the higher the priority channel, the better the reception rate, and the lower the priority channel, the lower the reception rate stochastically. Therefore, the power is preferentially reduced from the channel having the lower priority. Channel priorities may be determined as described in Cases 1-1 to 1-11, and priorities between component carriers may be further considered. As an example, when a terminal attempts uplink transmission using multiple component carriers, some important control information or important messages in the uplink transmission message may first be transmitted to a particular component carrier. In this case, a high priority may be assigned to a specific carrier wave to which important control information is transmitted.

The priority criterion method can be modified to a simpler method by limiting the damping coefficient to 0 or 1 (αij, βij {0,1}). That is, the transmission power is set to 0 in order from the channel with the lowest priority in the CC (group), and the sum of the transmission powers of the channels is the transmission power limit value (P) in the CC (group).^{CC = i}_Max) Can be smaller. As a result, the lower priority channel is not transmitted, and the higher priority channel is transmitted with the original transmission power.

The same attenuation reference method reduces the same amount from the power of all channels within each CC (group) beyond the transmit power limit in the CC (group). That is, all channels within the CC (group) are subject to equal power attenuation penalties. This method is useful when the difference between the sum of the transmission powers of the channels in the CC (group) and the maximum transmission power value of the CC (group) is small. In the same attenuation ratio reference method, the same attenuation coefficient can be applied to all channels in each CC (group) beyond the transmission power limit in the CC (group). The same attenuation reference method is a method of reducing by the same amount on a linear scale, and the same attenuation ratio reference method is a method of reducing by the same amount on a dB scale.

<u style="single">Example 3: Power control by antenna with MIMO</u> The power control method exemplified above can be similarly applied when using transmission diversity or spatial multiplexing using MIMO. In this case, the methods described above correspond to operations in layers, streams or antennas. If the terminal has multiple transmit antennas, the maximum transmit power in the power amplifier for each antenna is P.^{antenna, n}_maxCan be limited to (where n is the antenna index). The maximum transmit power of each antenna may be limited by the characteristics of the power amplifier (eg, class) or (additionally) by broadcast or RRC notification. The upper limit of the usable transmission power of the terminal is limited by the sum of the maximum transmission powers of each antenna and the minimum value of the maximum transmission powers of the terminals, as in Equation 13.

(Equation 13)<maths num="15"><img file="JP5508563B2_D0015.tif" /></maths>

When there is a limit on the transmission power for each CC (group), the upper limit of the transmission power that can be used by the terminal can be expressed as in Equation 14.

(Equation 14)<maths num="16"><img file="JP5508563B2_D0016.tif" /></maths>

Hereinafter, the terminal operation when the power control is performed independently for each antenna is proposed as follows. For convenience, the case where only two antennas are present is illustrated, but it is also applicable when three or more antennas are used. Define the following symbols.

P^{antenna, n}_X-CH: Represents the power calculated to be assigned to the nth antenna. Due to power restrictions, the actual power allocated may be less than this. If there is no dB display, it means a linear scale. X-CH represents all physical channels transmitted to antenna n (eg, PUSCH, PUCCH, SRS or a combination thereof).

P^{antenna, n}_X-CH&gt; P^{antenna, n}_max, P^{antenna, m}_X-CH P^{antenna, m}_maxIn the case of, one of the antennas reaches the maximum power limit and the other antenna does not reach the maximum power limit. In this case, power control can be performed for each antenna as described below.

Step 1: Maximum transmit power limit by CC (group) (P)^{CC = i}_Max), The transmission power for each CC (group) can be adjusted as in the second embodiment. That is, for each CC (group), the sum of the channel transmission powers of all antennas is P.^{CC = i}_MaxIf it exceeds, adjust the transmission power. Stage 1 is included only when power control is performed by CC (group).

Step 2: Considering the maximum transmit power of the antennas, the transmit power of each antenna can be adjusted as with the options below. The transmission power of the antenna may be adjusted by applying various methods (examples, priorities) exemplified in the first and second embodiments.

Option 1: If a large number of transmitting antennas are used, they may be precoded for transmission. In order to decode the precoded signal at the receiving end, it is necessary to know the precoding matrix used at the transmitting end and decode it in the reverse order of the transmitting end. However, if the power ratio of each antenna is not maintained by the power limitation of the antenna, the precoding matrix applied from the transmitting end is distorted and the reception error rate increases. Therefore, distortion of the precoding matrix can be prevented by adjusting the power of the antenna without the transmission power limit at the same ratio according to the antenna having the transmission power limit. That is, the transmission power of the antenna that does not reach the maximum power limit is reduced together with the transmission power of the antenna that exceeds the power limit so that the transmission power ratio is maintained the same. When there are three or more antennas, the transmission power of the remaining antennas may be adjusted at the same ratio according to the antenna transmission power reduced at the maximum ratio. Power actually used for transmission in option 1<maths num="17"><img file="JP5508563B2_D0017.tif" /></maths>Is as follows.

(Equation 15)<maths num="18"><img file="JP5508563B2_D0018.tif" /></maths>

Equation 15 represents the actual transmission power when there is no power limit.

(Equation 16)<maths num="19"><img file="JP5508563B2_D0019.tif" /></maths>

Equation 16 represents the actual transmission power when there is a power limit. Referring to Equation 16, the actual transmission power of the antenna n is limited to the maximum transmission power because the sum of the transmission powers of the channels of the antenna n exceeds the maximum transmission power. On the other hand, for the antenna m, P so that the sum of the transmission powers of the channels does not exceed the maximum transmission power, but the ratio of the transmission power to the antenna n is maintained.^{antenna, n}_Max/ P^{antenna, n}_X-CHThe transmission power decreases at the rate of.

Option 2: If the power ratio of each antenna indicated by the power control signal is not maintained by one of the power limits, the precoding matrix applied from the transmitting end will be distorted and the degree of distortion will be recognized at the receiving end. If this is not possible, the reception error rate will increase. However, when the precoding matrix used at the transmitting end is indirectly estimated from the dedicated reference signal (DRS), the distortion of the precoding matrix according to the change in the transmission power ratio of the antenna can also be estimated. In this case, it is not necessary to reduce the transmission power of the antenna having no power limit in order to match the transmission power ratio as in option 1. Therefore, only the transmission power of the antenna that has reached the maximum power limit may be transmitted by clipping the maximum transmission power of the corresponding antenna. The power actually used for transmission in Option 2 is as follows.

(Equation 17)<maths num="20"><img file="JP5508563B2_D0020.tif" /></maths>

Equation 17 represents the actual transmission power when there is no power limit.

(Equation 18)<maths num="21"><img file="JP5508563B2_D0021.tif" /></maths>

Equation 18 represents the actual transmission power when there is a power limit. Referring to Equation 18, the actual transmit power of antenna n is limited to the maximum transmit power because the sum of the transmit powers of the channels of antenna n exceeds the maximum transmit power. On the other hand, the antenna m is transmitted without power adjustment because the sum of the transmission powers of the channels does not exceed the maximum transmission power.

FIG. 12 is a diagram showing base stations and terminals to which Examples can be applied to the present invention.

With reference to FIG. 12, the wireless communication system includes a base station (BS) 110 and a terminal (UE) 120. In the downlink, the transmitter is part of base station 110 and the receiver is part of terminal 120. In the uplink, the transmitter is part of terminal 120 and the receiver is part of base station 110. Base station 110 includes processor 112, memory 114 and radio frequency (RF) unit 116. Processor 112 may be configured to embody the procedures and / or methods proposed in the present invention. The memory 114 is connected to the processor 112 and stores various information related to the operation of the processor 112. The RF unit 116 is connected to the processor 112 to transmit and / or receive radio signals. Terminal 120 includes processor 122, memory 124 and RF unit 126. Processor 122 may be configured to embody the procedures and / or methods proposed in the present invention. The memory 124 is connected to the processor 122 and stores various information related to the operation of the processor 122. RF unit DOO 126 is coupled to the processor 122, transmits and / or receives a radio signal. The base station 110 and / or the terminal 120 may include a single antenna or may include multiple antennas.

The examples described above are a combination of the components and features of the present invention. Each component or feature shall be considered as selective unless otherwise explicitly mentioned. Each component or feature may be implemented in a form that is not combined with other components or features, or some components and / or features may be combined to form an embodiment of the present invention. The order of operations described in the examples of the present invention can be changed. A partial configuration or feature of one embodiment may be included in another embodiment or replaced with a corresponding configuration or feature of another embodiment. It is clear that in the claims, claims that are not explicitly cited can be combined to form an example, or can be included as a new claim by post-application amendment.

In the present specification, the embodiment of the present invention has been described focusing on the data transmission / reception relationship between the terminal and the base station. In some cases, the specific operation performed by the base station in the present specification may be performed by its higher-level node. That is, it is clear that various operations performed for communication with a terminal in a communication network consisting of a large number of communication network nodes including a base station may be performed by the base station or another communication network node other than the base station. Is. Base stations can be replaced with terms such as fixed station, node B, enhanced node B (eNB), and access point. In addition, the terminal can be replaced with terms such as a user device (UE), a mobile device (MS), and a mobile subscriber station (MSS).

The embodiments according to the present invention can be embodied by various means such as hardware, firmware, software or a combination thereof. In the case of hardware implementation, one embodiment of the invention is one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs). ), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

In the case of realization by firmware or software, one embodiment of the present invention may be embodied in the form of a module, procedure, function or the like that performs the function or operation described above. The software code may be stored in a memory unit and driven by a processor. The memory unit is provided inside or outside the processor and can exchange data with the processor by various already known means.

It is obvious to those skilled in the art that the present invention can be embodied in another particular form without departing from the features of the present invention. Therefore, the above detailed description should not be construed in a restrictive manner in any respect and should be considered as an example. The scope of the invention should be determined by reasonable interpretation of the appended claims, and any modifications within the equal scope of the invention are within the scope of the invention.

The present invention can be applied to wireless communication systems. In particular, the present invention can be applied to a method for controlling uplink transmission power and a device for that purpose.