KR20110133448A - Method for transmitting aperiodic srs and controlling for uplink transmit power of aperiodic srs based on aperiodic srs triggering - Google Patents

Abstract

PURPOSE: A sounding reference signal(SRS) transmission method based on aperiodic sounding reference signal triggering of a terminal and an uplink power control method for aperiodic SRS transmission are provided to improve communication performance by selectively transmitting an aperiodic SRS of specific aperiodic SRS composition information. CONSTITUTION: A plurality of aperiodic sounding reference signal(SRS) composition information is received from a base station. An indicator triggering aperiodic SRS transmission is received from the base station. The specific aperiodic SRS composition information is selected among the multiple aperiodic SRS composition information. The SRS composition information is based on one or more among a sub-frame index receiving the indicator, a time relation between an aperiodic SRS transmission sub-frame corresponding to a reception sub-frame of the indicator, and an uplink channel state. An aperiodic SRS with respect to the indicator is transmitted based on the selected aperiodic SRS composition information.

Description

Method for transmitting aperiodic SRS based on aperiodic SRS triggering method for transmitting aperiodic SRS based on aperiodic SRS and controlling for uplink transmit power for transmitting aperiodic SRS

The present invention relates to a wireless communication system, and more particularly, to an aperiodic sounding reference signal (SRS) triggering-based SRS transmission method and an uplink transmission power for transmitting an aperiodic SRS. It relates to a control method.

Wireless communication technology has been developed to LTE based on Wideband Code Division Multiple Access (WCDMA), but the demands and expectations of users and operators are continuously increasing. In addition, as other radio access technologies continue to be developed, new technological evolution is required to be competitive in the future. Reduced cost per bit, increased service availability, the use of flexible frequency bands, simple structure and open interface, and adequate power consumption of the terminal are required.

Recently, 3GPP has been working on standardization of follow-up technology for LTE. In the present specification, the above technique is referred to as 'LTE-A'. One of the major differences between LTE and LTE-A systems is the difference in system bandwidth and the introduction of repeaters. The LTE-A system aims to support broadband of up to 100 MHz, and to this end, carrier aggregation or bandwidth aggregation technology is used to achieve broadband using multiple frequency blocks. Doing. Carrier aggregation allows the use of multiple frequency blocks as one large logical frequency band to use a wider frequency band. The bandwidth of each frequency block may be defined based on the bandwidth of the system block used in the LTE system. Each frequency block is transmitted using a component carrier.

The 3GPP LTE-A system supports aperiodic SRS transmission in addition to the conventional periodic SRS transmission to ensure the accuracy of uplink channel estimation. In order to support such aperiodic SRS transmission, uplink transmission power control for aperiodic SRS configuration information and aperiodic SRS transmission is required. However, there are no concrete proposals for controlling specific aperiodic SRS configuration information for supporting aperiodic SRS transmission and a method for controlling uplink transmission power for aperiodic SRS transmission.

An object of the present invention is to provide an SRS transmission method based on aperiodic sounding reference signal (SRS) triggering.

Another object of the present invention is to provide a method for controlling uplink transmission power for transmitting aperiodic SRS by a terminal.

Another object of the present invention is to provide a terminal device for transmitting an aperiodic SRS based on an aperiodic sounding reference signal (SRS) triggering.

Another object of the present invention is to provide a terminal apparatus for controlling uplink transmission power for transmitting aperiodic SRS.

The technical problems to be solved by the present invention are not limited to the technical problems and other technical problems which are not mentioned can be understood by those skilled in the art from the following description.

In order to achieve the above technical problem, a method for transmitting an SRS based on an aperiodic sounding reference signal (SRS) triggering according to the present invention comprises a plurality of aperiodic SRS configurations from a base station. receiving configuration information; Receiving an indicator for triggering aperiodic SRS transmission from the base station; Based on at least one of a subframe index for receiving the aperiodic SRS transmission triggering indicator, a time relationship between a receiving subframe of the aperiodic SRS transmission triggering indicator, and a non-periodic SRS transmission subframe corresponding to the aperiodic SRS transmission triggering indicator, and an uplink channel state Selecting specific aperiodic SRS configuration information among the aperiodic SRS configuration information of the; And transmitting aperiodic SRS for the aperiodic SRS transmission triggering indicator based on the selected aperiodic SRS configuration information, wherein the plurality of aperiodic SRS configuration information corresponds to the aperiodic SRS transmission triggering indicator. It may include information about resources for transmitting the aperiodic SRS. Here, the transmission of the aperiodic SRS is the first aperiodic, which is the fastest subframe among the preconfigured periodic SRS transmission subframes subsequent from the subframe n, if the subframe receiving the aperiodic SRS transmission triggering indicator is subframe n. If the subframe receiving the SRS transmission subframe or the aperiodic SRS transmission triggering indicator is subframe n, a second aperiodic SRS that is the fastest subframe among the preconfigured periodic SRS transmission subframes after subframe n + 3. It may be performed through a transmission subframe.

If the subframe index n receiving the aperiodic SRS transmission triggering indicator is an even number, the partial band on the frequency axis of the first aperiodic SRS subframe or the second aperiodic SRS subframe in the step of transmitting the aperiodic SRS. The aperiodic SRS may be transmitted through (partial-band). If the transmission power is not sufficient to transmit the aperiodic SRS corresponding to the aperiodic SRS transmission triggering indicator, the aperiodic SRS is transmitted through a predefined fallback aperiodic SRS resource in the sub-band. Can be.

Or, if the subframe index n having received the aperiodic SRS transmission triggering indicator is odd, transmitting the aperiodic SRS on the frequency axis of the first aperiodic SRS subframe or the second aperiodic SRS subframe. The aperiodic SRS may be transmitted over a full band. If the transmission power is not sufficient to transmit the aperiodic SRS corresponding to the aperiodic SRS transmission triggering indicator, the aperiodic SRS is transmitted through a predefined fallback aperiodic SRS resource in the full-band. Can be.

Alternatively, when the time relationship between subframe n, which is a subframe that receives the aperiodic SRS transmission triggering indicator, and one or more periodic SRS transmission subframes allocated to the UE, is a time difference corresponding to four subframes, the plurality of ratios A first aperiodic SRS configuration may be selected among the periodic SRS configurations, and the aperiodic SRS may be transmitted through the first aperiodic SRS subframe according to the first aperiodic SRS configuration. Here, the aperiodic SRS may be transmitted through the full-band on the frequency axis of the first aperiodic SRS subframe.

Alternatively, if the time relationship between subframe n, which is a subframe receiving the aperiodic SRS transmission triggering indicator, and one or more periodic SRS transmission subframes allocated to the UE is not a time difference corresponding to four subframes, A second aperiodic SRS configuration may be selected among the aperiodic SRS configurations, and the aperiodic SRS may be transmitted through the second aperiodic SRS subframe according to the second aperiodic SRS configuration. Here, the aperiodic SRS may be transmitted through a partial-band on the frequency axis of the second aperiodic SRS subframe.

Alternatively, when the uplink channel state is not better than a predefined channel state, a second aperiodic SRS configuration is selected among the plurality of aperiodic SRS configurations, and the first non-periodic SRS configuration is selected. The aperiodic SRS may be transmitted through a partial-band on a frequency axis of the periodic SRS subframe or the second aperiodic SRS subframe.

Alternatively, when the uplink channel state is better than a predefined channel state, a first aperiodic SRS configuration is selected from the plurality of aperiodic SRS configurations, and the first aperiodic SRS configuration is selected according to the first aperiodic SRS configuration. The aperiodic SRS may be transmitted on a full frame on the frequency axis of the subframe or the second aperiodic SRS subframe.

According to an aspect of the present invention, there is provided a method for a terminal according to an embodiment of the present invention to control uplink transmission power for aperiodic sounding reference signal (SRS) transmission. Receiving a power offset value for the aperiodic SRS transmission from; Determining the aperiodic SRS transmission power value using the power offset value for the aperiodic SRS transmission; And transmitting the aperiodic SRS at the determined aperiodic SRS transmission power value. The power offset value for the aperiodic SRS transmission only may be a value received for each terminal as a value received through higher layer signaling. The method may further include receiving an indicator for triggering the aperiodic SRS transmission from the base station, and the aperiodic SRS transmission may be performed according to the aperiodic SRS transmission triggering indicator. In addition, the aperiodic SRS transmission power value determination may be determined in units of subframes.

In order to achieve the above technical problem, in a wireless communication system according to another embodiment of the present invention, a terminal controls uplink transmission power for aperiodic sounding reference signal (SRS) transmission. The method includes receiving a power offset value for periodic SRS transmission and a power offset value for aperiodic SRS transmission from a base station; Receiving an indicator from the base station to trigger aperiodic SRS transmission; And determining a transmission power value for the aperiodic SRS transmission using the power offset value for the aperiodic SRS transmission according to the aperiodic SRS transmission triggering indicator.

In order to solve the above another technical problem, the terminal apparatus for transmitting the SRS based on the aperiodic sounding reference signal (SRS) triggering, a plurality of aperiodic SRS configuration from the base station (configuration) A receiver receiving an indicator for triggering information and aperiodic SRS transmission; Based on at least one of a subframe index for receiving the aperiodic SRS transmission triggering indicator, a time relationship between a receiving subframe of the aperiodic SRS transmission triggering indicator, and a non-periodic SRS transmission subframe corresponding to the aperiodic SRS transmission triggering indicator, and an uplink channel state A processor for selecting specific aperiodic SRS configuration information among the aperiodic SRS configuration information of the processor; And a transmitter for transmitting an aperiodic SRS for the aperiodic SRS transmission triggering indicator based on the selected aperiodic SRS configuration information, wherein the plurality of aperiodic SRS configuration information corresponds to the aperiodic SRS transmission triggering indicator. It may include information about resources for transmitting the aperiodic SRS.

In order to solve the above technical problem, the terminal apparatus for controlling uplink transmission power for aperiodic sounding reference signal (SRS) transmission according to the present invention, the aperiodic from the base station A receiver receiving a power offset value for SRS transmission; A processor for determining the aperiodic SRS transmission power value using the power offset value for the aperiodic SRS transmission; And a transmitter for transmitting the aperiodic SRS at the determined aperiodic SRS transmission power value.

According to the aperiodic SRS configuration according to the present invention, the UE helps to estimate the uplink channel state more accurately by transmitting an aperiodic SRS. In addition, the UE may be configured based on a plurality of subframe indexes based on a subframe index for receiving the aperiodic SRS transmission triggering indicator, a time relationship between a reception subframe of the aperiodic SRS transmission triggering indicator, and a corresponding aperiodic SRS transmission subframe, or an uplink channel state. Communication performance can be improved by selecting specific aperiodic SRS configuration information among the aperiodic SRS configuration information and transmitting the aperiodic SRS.

In addition, it not only helps to more accurately estimate uplink channel state, but also through adaptive aperiodic SRS configuration switching, uplink signal interference in SRS coverage issues and co-channel HetNet scenarios. Solve problems efficiently

In addition, aperiodic SRS transmission power may be determined by using an uplink power control equation for aperiodic SRS transmission proposed in the present invention, and aperiodic SRS may be transmitted.

Effects obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description in order to provide a thorough understanding of the present invention, provide an embodiment of the present invention and together with the description, illustrate the technical idea of the present invention.
1 is a block diagram showing the configuration of a base station 205 and a terminal 210 in a wireless communication system 200 according to the present invention;
2 is a diagram illustrating a structure of a radio frame used in a 3GPP LTE system as an example of a mobile communication system;
3A and 3B illustrate structures of downlink and uplink subframes of a 3GPP LTE system as an example of a mobile communication system;
4 illustrates a downlink time-frequency resource grid structure used in the present invention;
5 is a configuration diagram of a general multiple antenna (MIMO) communication system,
6 shows a channel from NT transmit antennas to receive antenna i,
7A and 7B illustrate reference signal patterns in a 3GPP LTE system as an example of a mobile communication system, and FIG. 7A illustrates reference signal patterns when a normal CP is applied. 7 (b) is a view showing a reference signal pattern when extended CP is applied,
8 illustrates an example of an uplink subframe configuration including an SRS symbol;
9A and 9B illustrate examples of subframes for cell-specific periodic SRS transmission and examples of subframes for UE-specific periodic SRS transmission, respectively;
10A, 10B, and 10C illustrate an example of an operation of dynamically selecting a plurality of SRS configurations using a time relationship between a subframe receiving an aperiodic SRS triggering grant and a corresponding aperiodic SRS transmission subframe, respectively. Shown,
FIG. 11 is a diagram illustrating an aperiodic SRS operation when a subframe index classification at the time of arrival of an aperiodic SRS triggering grant is applied as another criterion. FIG.
12A and 12B illustrate an example of an aperiodic SRS subframe of an SRS configuration, respectively;
FIG. 13 is a diagram for describing switching of aperiodic SRS configuration operation according to the aperiodic SRS configuration of FIGS. 12A and 12B and a time point when a UE receives an aperiodic SRS triggering grant; FIG.
14A and 14B are diagrams for explaining fallback aperiodic SRS transmission, respectively;
15A to 15C are diagrams for describing a method of reusing a cell-specific SRS resource for efficient aperiodic SRS transmission when a cell-specific SRS resource (subframe) is allocated with a period of 2 ms, respectively.
16 illustrates a UE-specific periodic SRS subframe,
17A to 17C are diagrams for explaining an operation of dynamically selecting a plurality of SRS configurations using a time relationship between an aperiodic SRS triggering grant reception subframe and a corresponding aperiodic SRS transmission subframe, respectively;
18 is a diagram illustrating aperiodic SRS transmission corresponding to a case in which a subframe index classification at the time of receiving an aperiodic SRS triggering grant of a terminal is applied as another criterion;
19A and 19B illustrate an example of an aperiodic SRS subframe of an SRS configuration, respectively.
20 is a view for explaining the switching of the aperiodic SRS configuration operation according to the configuration of the aperiodic SRS of Figure 19a and 19b and when the terminal receives the aperiodic SRS triggering grant, and,
21A and 21B illustrate a new scheme of aperiodic SRS transmission in which some of the aperiodic SRS transmission resources are divided into fallback aperiodic SRS transmission resources and used.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. For example, the following detailed description will be described in detail on the assumption that the mobile communication system is a 3GPP LTE, LTE-A system, but is also applied to any other mobile communication system except for the specific matters of 3GPP LTE, LTE-A. Applicable

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

In the following description, it is assumed that the UE collectively refers to a mobile stationary or stationary user equipment such as a UE (User Equipment), an MS (Mobile Station), and an AMS (Advanced Mobile Station). In addition, it is assumed that the base station collectively refers to any node of the network side that communicates with the terminal such as a Node B, an eNode B, a base station (BS), and an access point (AP).

In a mobile communication system, a user equipment may receive information from a base station through downlink / backhaul downlink, and the terminal may also transmit information through uplink. The information transmitted or received by the terminal and the base station includes data and various control information, and various physical channels exist according to the type and purpose of the information transmitted or received by the terminal and the base station.

1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100.

Although one base station 105 and one terminal 110 are shown to simplify the wireless communication system 100, the wireless communication system 100 may include one or more base stations and / or one or more terminals. .

2, the base station 105 includes a transmit (Tx) data processor 115, a symbol modulator 120, a transmitter 125, a transmit / receive antenna 130, a processor 180, a memory 185, and a receiver ( 190, a symbol demodulator 195, and a receive data processor 197. The terminal 110 transmits (Tx) the data processor 165, the symbol modulator 170, the transmitter 175, the transmit / receive antenna 135, the processor 155, the memory 160, the receiver 140, and the symbol. It may include a demodulator 155 and a receive data processor 150. Although the antennas 130 and 135 are shown as one at the base station 105 and the terminal 110, respectively, the base station 105 and the terminal 110 are provided with a plurality of antennas. Accordingly, the base station 105 and the terminal 110 according to the present invention support a multiple input multiple output (MIMO) system. In addition, the base station 105 according to the present invention may support both a single user-MIMO (SU-MIMO) and a multi-user-MIMO (MU-MIMO) scheme.

On the downlink, the transmit data processor 115 receives the traffic data, formats the received traffic data, codes it, interleaves and modulates (or symbol maps) the coded traffic data, and modulates the symbols ("data"). Symbols "). The symbol modulator 120 receives and processes these data symbols and pilot symbols to provide a stream of symbols.

The symbol modulator 120 multiplexes the data and pilot symbols and sends them to the transmitter 125. In this case, each transmission symbol may be a data symbol, a pilot symbol, or a signal value of zero. In each symbol period, pilot symbols may be sent continuously. The pilot symbols may be frequency division multiplexed (FDM), orthogonal frequency division multiplexed (OFDM), time division multiplexed (TDM), or code division multiplexed (CDM) symbols.

Transmitter 125 receives the stream of symbols and converts it into one or more analog signals, and further adjusts (eg, amplifies, filters, and frequency upconverts) the analog signals to provide a wireless channel. Generates a downlink signal suitable for transmission through the antenna, and then, the antenna 130 transmits the generated downlink signal to the terminal.

In the configuration of the terminal 110, the antenna 135 receives the downlink signal from the base station and provides the received signal to the receiver 140. Receiver 140 adjusts the received signal (eg, filtering, amplifying, and frequency downconverting), and digitizes the adjusted signal to obtain samples. The symbol demodulator 145 demodulates the received pilot symbols and provides them to the processor 155 for channel estimation.

The symbol demodulator 145 also receives a frequency response estimate for the downlink from the processor 155 and performs data demodulation on the received data symbols to obtain a data symbol estimate (which is an estimate of the transmitted data symbols). Obtain and provide data symbol estimates to a receive (Rx) data processor 150. Receive data processor 150 demodulates (ie, symbol de-maps), deinterleaves, and decodes the data symbol estimates to recover the transmitted traffic data.

 The processing by symbol demodulator 145 and receiving data processor 150 is complementary to the processing by symbol modulator 120 and transmitting data processor 115 at base station 205, respectively.

The terminal 110 is on the uplink, and the transmit data processor 165 processes the traffic data to provide data symbols. The symbol modulator 170 may receive and multiplex data symbols, perform modulation, and provide a stream of symbols to the transmitter 175. The transmitter 175 receives and processes a stream of symbols to generate an uplink signal. The antenna 135 transmits the generated uplink signal to the base station 105.

In the base station 105, an uplink signal is received from the terminal 110 through the antenna 130, and the receiver 190 processes the received uplink signal to obtain samples. The symbol demodulator 195 then processes these samples to provide received pilot symbols and data symbol estimates for the uplink. The received data processor 197 processes the data symbol estimates to recover the traffic data transmitted from the terminal 110.

Processors 155 and 180 of the terminal 110 and the base station 105 respectively instruct (eg, control, coordinate, manage, etc.) operations at the terminal 110 and the base station 105, respectively. Respective processors 155 and 180 may be connected to memories 160 and 185 that store program codes and data. The memory 160, 185 is coupled to the processor 180 to store the operating system, applications, and general files.

The processors 155 and 180 may also be referred to as controllers, microcontrollers, microprocessors, microcomputers, or the like. The processors 155 and 180 may be implemented by hardware or firmware, software, or a combination thereof. When implementing embodiments of the present invention using hardware, application specific integrated circuits (ASICs) or digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) configured to perform the present invention. Field programmable gate arrays (FPGAs) may be provided in the processors 155 and 180.

Meanwhile, when implementing embodiments of the present invention using firmware or software, the firmware or software may be configured to include a module, a procedure, or a function for performing the functions or operations of the present invention, and to perform the present invention. The firmware or software configured to be may be provided in the processors 155 and 180 or stored in the memory 160 and 185 to be driven by the processors 155 and 180.

The layers of the air interface protocol between the terminal and the base station between the wireless communication system (network) are based on the lower three layers of the open system interconnection (OSI) model, which is well known in the communication system. ), And the third layer L3. The physical layer belongs to the first layer and provides an information transmission service through a physical channel. A Radio Resource Control (RRC) layer belongs to the third layer and provides control radio resources between the UE and the network. The terminal and the base station may exchange RRC messages through the wireless communication network and the RRC layer.

2 is a diagram illustrating a structure of a radio frame used in a 3GPP LTE system as an example of a mobile communication system.

Referring to FIG. 2, one radio frame has a length of 10 ms (327200 Ts) and consists of 10 equally sized subframes (subframes). Each subframe has a length of 1 ms and consists of two slots. Each slot has a length of 0.5 ms (15360 Ts). Here, Ts represents a sampling time and is represented by Ts = 1 / (15 kHz x 2048) = 3.2552 x 10 -8 (about 33 ns). The slot includes a plurality of OFDM symbols or SC-FDMA symbols in the time domain and a plurality of resource blocks in the frequency domain.

In the LTE system, one resource block includes 12 subcarriers x 7 (6) OFDM symbols or a single carrier-frequency division multiple access (SC-FDMA) symbol. Transmission time interval (TTI), which is a unit time for transmitting data, may be determined in units of one or more subframes. The structure of the above-described radio frame is only an example, and the number of subframes included in the radio frame or the number of slots included in the subframe, the number of OFDM symbols or SC-FDMA symbols included in the slot may be variously changed. have.

3A and 3B illustrate structures of downlink and uplink subframes of a 3GPP LTE system as an example of a mobile communication system.

Referring to FIG. 3A, one downlink subframe includes two slots in the time domain. Up to three OFDM symbols of the first slot in the downlink subframe are control regions to which control channels are allocated, and the remaining OFDM symbols are data regions to which a Physical Downlink Shared Channel (PDSCH) is allocated.

Downlink control channels used in 3GPP LTE include a Physical Control Format Indicator Channel (PCFICH), a Physical Downlink Control Channel (PDCCH), a Physical Hybrid-ARQ Indicator Channel (PHICH), and the like. The PCFICH transmitted in the first OFDM symbol of the subframe carries information about the number of OFDM symbols (that is, the size of the control region) used for transmission of control channels in the subframe. Control information transmitted through the PDCCH is called downlink control information (DCI). DCI indicates uplink resource allocation information, downlink resource allocation information, and uplink transmission power control command for arbitrary UE groups. The PHICH carries an ACK (Acknowledgement) / NACK (Not-Acknowledgement) signal for an uplink HARQ (Hybrid Automatic Repeat Request). That is, the ACK / NACK signal for the uplink data transmitted by the UE is transmitted on the PHICH.

Now, a PDCCH which is a downlink physical channel will be described.

The base station transmits resource allocation and transmission format of PDSCH (also referred to as DL grant), resource allocation information of PUSCH (also referred to as UL grant) through PDCCH, a set of transmission power control commands for individual terminals in any terminal group, and Enable activation of Voice over Internet Protocol (VoIP). A plurality of PDCCHs may be transmitted in the control region, and the terminal may monitor the plurality of PDCCHs. The PDCCH consists of an aggregation of one or several consecutive Control Channel Elements (CCEs). The PDCCH composed of one or several consecutive CCEs may be transmitted through the control region after subblock interleaving. CCE is a logical allocation unit used to provide a PDCCH with a coding rate according to a state of a radio channel. The CCE corresponds to a plurality of resource element groups. The format of the PDCCH and the number of possible bits of the PDCCH are determined by the correlation between the number of CCEs and the coding rate provided by the CCEs.

Control information transmitted through the PDCCH is called downlink control information (DCI). Table 1 below shows DCI according to DCI format.

DCI format 0 indicates uplink resource allocation information, DCI formats 1 to 2 indicate downlink resource allocation information, and DCI formats 3 and 3A indicate uplink transmit power control (TPC) commands for arbitrary UE groups. .

In the LTE system, a brief description will be given of a method for mapping a resource for transmitting a PDCCH by a base station.

이다). PDCCH는 다음 표 3에 나타낸 바와 같이 다중 포맷을 지원한다. n개의 연속 CCE들로 구성된 하나의 PDCCH는 i mod n =0을 수행하는 CCE부터 시작한다(여기서 i는 CCE 번호이다). 다중 PDCCH들은 하나의 서브프레임으로 전송될 수 있다. In general, the base station may transmit scheduling assignment information and other control information through the PDCCH. The physical control channel may be transmitted in one aggregation or a plurality of continuous control channel elements (CCEs). One CCE includes nine Resource Element Groups (REGs). The number of REGs not allocated to the Physical Control Format Indicator CHhannel (PCFICH) or the Physical Hybrid Automatic Repeat Request Indicator Channel (PHICH) is NREG. The CCEs available in the system are from 0 to NCCE-1 (where

to be). The PDCCH supports multiple formats as shown in Table 3 below. One PDCCH composed of n consecutive CCEs starts with a CCE that performs i mod n = 0 (where i is a CCE number). Multiple PDCCHs may be transmitted in one subframe.

Referring to Table 2, the base station may determine the PDCCH format according to how many areas, such as control information, to send. The UE may reduce overhead by reading control information in units of CCE. Similarly, the repeater can also read control information and the like in units of R-CCE. In the LTE-A system, a resource element (RE) may be mapped in units of a relay-control channel element (R-CCE) to transmit an R-PDCCH for an arbitrary repeater.

Referring to FIG. 3B, an uplink subframe may be divided into a control region and a data region in the frequency domain. The control region is allocated to a physical uplink control channel (PUCCH) that carries uplink control information. The data area is allocated to a Physical Uplink Shared CHannel (PUSCH) for carrying user data. In order to maintain a single carrier characteristic, one UE does not simultaneously transmit a PUCCH and a PUSCH. PUCCH for one UE is allocated to an RB pair in one subframe. RBs belonging to the RB pair occupy different subcarriers in each of two slots. The RB pair assigned to the PUCCH is frequency hopped at the slot boundary.

4 illustrates a downlink time-frequency resource grid structure used in the present invention.

×

개의 부반송파(subcarrier)와

개의 OFDM(Orthogonal Frequency Division Multiplexing) 심볼로 구성되는 자원 격자(resource grid) 구조로 이용한다. 여기서,

은 하향링크에서의 자원 블록(RB: Resource Block)의 개수를 나타내고,

는 하나의 RB을 구성하는 부반송파의 개수를 나타내고,

는 하나의 하향링크 슬롯에서의 OFDM 심볼의 개수를 나타낸다.

의 크기는 셀 내에서 구성된 하향링크 전송 대역폭에 따라 달라지며

≤

≤

을 만족해야 한다. 여기서,

는 무선 통신 시스템이 지원하는 가장 작은 하향링크 대역폭이며

는 무선 통신 시스템이 지원하는 가장 큰 하향링크 대역폭이다.

=6이고

=110일 수 있지만, 이에 한정되는 것은 아니다. 하나의 슬롯 내에 포함된 OFDM 심볼의 개수는 순환 전치(CP: Cyclic Prefix)의 길이 및 부반송파의 간격에 따라 다를 수 있다. 다중안테나 전송의 경우에, 하나의 안테나 포트 당 하나의 자원 격자가 정의될 수 있다.The downlink signal transmitted in each slot

×

Subcarriers and

It is used as a resource grid structure composed of orthogonal frequency division multiplexing (OFDM) symbols. here,

Represents the number of resource blocks (RBs) in downlink,

Represents the number of subcarriers constituting one RB,

Denotes the number of OFDM symbols in one downlink slot.

The size of depends on the downlink transmission bandwidth configured within the cell.

≤

≤

Must be satisfied. here,

Is the smallest downlink bandwidth supported by the wireless communication system.

Is the largest downlink bandwidth supported by the wireless communication system.

= 6

= 110, but is not limited thereto. The number of OFDM symbols included in one slot may vary depending on the length of a cyclic prefix (CP) and the interval of subcarriers. In the case of multiple antenna transmission, one resource grid may be defined per one antenna port.

-1 중 어느 하나의 값을 갖고, l는 0,...,

-1 중 어느 하나의 값을 갖는다. Each element in the resource grid for each antenna port is called a resource element (RE) and is uniquely identified by an index pair (k, l) in the slot. Where k is the index in the frequency domain, l is the index in the time domain and k is 0, ...,

Has a value of -1 and l is 0, ...,

It has any one of -1.

개의 연속적인 OFDM 심볼과 주파수 영역의

개의 연속적인 부반송파로 정의된다. 여기서

과

는 미리 결정된 값일 수 있다. 예를 들어

과

는 다음 표 1과 같이 주어질 수 있다. 따라서 하나의 PRB는

×

개의 자원 요소로 구성된다. 하나의 PRB는 시간 영역에서는 하나의 슬롯에 대응되고 주파수 영역에서는 180kHz에 대응될 수 있지만 이에 한정되는 것은 아니다. The resource block shown in FIG. 4 is used to describe a mapping relationship between certain physical channels and resource elements. The RB may be divided into a physical resource block (PRB) and a virtual resource block (VRB). The one PRB is a time domain

Contiguous OFDM symbols and frequency domain

It is defined as two consecutive subcarriers. here

and

May be a predetermined value. E.g

and

Can be given as Table 1 below. So one PRB

×

It consists of four resource elements. One PRB may correspond to one slot in the time domain and 180 kHz in the frequency domain, but is not limited thereto.

-1 까지의 값을 갖는다. 주파수 영역에서의 PRB 넘버(number) n_PRB와 하나의 슬롯 내에서의 자원 요소 (k,l) 사이의 관계는

를 만족한다.PRB is at 0 in the frequency domain

It has a value up to -1. The relationship between the PRB number n _PRB in the frequency domain and the resource element (k, l) in one slot

.

The size of the VRB is equal to the size of the PRB. The VRB may be defined by being divided into a localized VRB (LVRB) and a distributed VRB (DVRB). For each type of VRB, a pair of VRBs in two slots in one subframe are assigned together a single VRB number n _VRBs .

개의 VRB들은 각각 0부터

-1 중 어느 하나의 인덱스 (Index)를 할당 받고, 위의 2개의 슬롯 중 제 2 슬롯에 속하는

개의 VRB들도 마찬가지로 각각 0부터

-1 중 어느 하나의 인덱스를 할당받는다.The VRB may have the same size as the PRB. Two types of VRBs are defined, the first type being a localized VRB (LVRB) and the second type being a distributed VRB (DVRB). For each type of VRB, a pair of VRBs are allocated over two slots of one subframe with a single VRB index (hereinafter may also be referred to as VRB number). In other words, belonging to the first slot of the two slots constituting one subframe

VRBs from 0 each

Is assigned an index of any one of -1, and belongs to the second one of the two slots

VRBs likewise start with 0

The index of any one of -1 is allocated.

Hereinafter, a general MIMO technology will be described. MIMO stands for "Multi-Input Multi-Output", and it is a method of improving transmission and reception data efficiency by adopting multiple transmission antennas and multiple reception antennas, instead of using one transmission antenna and one reception antenna. Say That is, a technique of increasing capacity or improving performance by using multiple antennas at a transmitting end or a receiving end of a wireless communication system. Hereinafter, "MIMO" will be referred to as "multi antenna".

Multi-antenna technology is an application of a technique of gathering and completing fragmented pieces of data received from multiple antennas without relying on a single antenna path to receive a whole message. This can improve the data transfer rate at a particular range or increase the system range for a particular data rate.

Next-generation mobile communication requires much higher data rates than conventional mobile communication, so efficient multi-antenna technology is required. In such a situation, MIMO communication technology is the next generation mobile communication technology that can be widely used in mobile communication terminals and repeaters, and attracts attention as a technology that can overcome the transmission limit of other mobile communication depending on the limit situation due to the expansion of data communication. have.

On the other hand, among the various transmission efficiency improvement technologies currently being studied, the multiple antenna (MIMO) technology using multiple antennas at both the transmitting and receiving ends is a method that can dramatically improve communication capacity and transmission / reception performance without additional frequency allocation or power increase. It is currently receiving the most attention.

5 is a configuration diagram of a general multiple antenna (MIMO) communication system.

As shown in FIG. 5, if the number of transmitting antennas is increased to NT and the number of receiving antennas is increased to NR at the same time, the theoretical channel transmission is proportional to the number of antennas, unlike when only a plurality of antennas are used in a transmitter or a receiver. Since the capacity increases, the transmission rate can be improved and the frequency efficiency can be significantly improved. The transmission rate according to the increase in the channel transmission capacity may be theoretically increased by multiplying the maximum transmission rate Ro by the following rate increase rate Ri in the case of using one antenna. The rate increase rate Ri may be expressed as in Equation 1 below.

In order to describe the communication method in the multi-antenna system as described above in more detail, mathematical modeling may be expressed as follows.

First, it is assumed that NT transmit antennas and NR receive antennas exist as shown in FIG. 5.

First, referring to the transmission signal, if there are NT transmission antennas as described above, since the maximum transmittable information is NT, it can be represented by a vector as shown in Equation 2 below.

에 있어 전송 전력을 달리할 수 있으며, 이 경우 각각의 전송 전력을 P1, P2, ...,

라 하면, 전송 전력이 조정된 전송 정보는 다음 수학식 3과 같은 벡터로 나타낼 수 있다.On the other hand, the respective transmission information S1, S2, ...,

In this case, the transmit power can be changed in this case, and in this case, each transmit power is P1, P2, ...,

In this case, the transmission information whose transmission power is adjusted may be represented by a vector as shown in Equation 3 below.

를 전송 전력의 대각행렬 P로 다음 수학식 4와 같이 나타낼 수 있다.Also,

Can be expressed by the diagonal matrix P of the transmission power as shown in Equation 4 below.

를 구성한다. 여기서, 가중치 행렬은 전송 정보를 전송 채널 상황 등에 따라 각 안테나에 적절히 분배해 주는 역할을 수행한다. 이와 같은 전송 신호 x1, x2, ... ,

를 벡터 x를 이용하여 다음 수학식 5와 같이 나타낼 수 있다.Meanwhile, the information vector whose transmission power is adjusted is then multiplied by the weight matrix W to actually transmit NT transmitted signals x1, x2, ...,

Configure Here, the weight matrix plays a role of properly distributing transmission information to each antenna according to a transmission channel situation. Such transmission signals x1, x2, ...,

Can be expressed as Equation 5 below using the vector x.

In Equation 5, w _ij represents a weight between the i th transmit antenna and the j th transmission information, and W is represented by a matrix. Such a matrix W is called a weight matrix or a precoding matrix.

On the other hand, the above-described transmission signal (x) can be considered divided into the case of using the spatial diversity and the case of using the spatial multiplexing.

In the case of using spatial multiplexing, since different signals are multiplexed and sent, the elements of the information vector s all have different values. In contrast, when spatial diversity is used, the same signal is sent through multiple channel paths. The elements of the vector s all have the same value.

을 벡터 y로 다음 수학식 6과 같이 나타내기로 한다.Of course, a method of mixing spatial multiplexing and spatial diversity is also conceivable. That is, for example, a case may be considered in which the same signal is transmitted using spatial diversity through three transmission antennas, and the remaining signals are spatially multiplexed from each other. Next, when there are N _R receiving antennas, the received signals are received signals y ₁ , y ₂ , ..., of each antenna.

Denote a vector y as shown in Equation 6 below.

Meanwhile, when modeling a channel in a multi-antenna communication system, channels may be classified according to the transmit / receive antenna index, and a channel passing through the receive antenna i from the transmit antenna j will be denoted as h _ij . Note that the order of the index of h _ij is that of the receiving antenna index first, and that of the transmitting antenna is later. These channels can be grouped together and displayed in vector and matrix form. An example of the vector display is described as follows.

6 is a diagram illustrating a channel from N _T transmit antennas to receive antenna i.

As shown in FIG. 6, a channel arriving from a total of N _T transmit antennas to a reception antenna i may be expressed as in Equation 7 below.

In addition, when all the channels passing through the NR receive antennas from the NT transmit antennas through the matrix representation as shown in Equation 7 can be expressed as Equation 8 below.

을 벡터로 표현하면 다음 수학식 9와 같다.On the other hand, since the real channel is added with white noise (AWGN) after passing through the channel matrix H as described above, white noise n1, n2, ..., added to each of the NR receiving antennas.

Is expressed as a vector as shown in Equation 9 below.

Through the modeling of the transmission signal, the reception signal, the channel, and the white noise as described above, each of the signals in the multi-antenna communication system may be represented by the following equation (10).

Meanwhile, the number of rows and columns of the channel matrix H indicating the state of the channel is determined by the number of transmit and receive antennas. As described above, in the channel matrix H, the number of rows becomes equal to the number NR of receive antennas, and the number of columns becomes equal to the number NT of transmit antennas. In other words, the channel matrix H becomes an NR x NT matrix.

In general, the rank of a matrix is defined as the minimum number of rows or columns that are independent of each other. Thus, the rank of the matrix cannot be greater than the number of rows or columns. For example, the rank (H) of the channel matrix H is limited as in Equation 11 below.

In a mobile communication system, when a transmitting end transmits a packet (or a signal) to a receiving end, a signal transmitted by a transmitting end may be transmitted through a wireless channel, and thus distortion of a signal may occur during transmission. In order to correctly receive the distorted signal at the receiver, the receiver can receive the correct signal by finding channel information and correcting distortion of the transmission signal by the channel information in the received signal. In order to find out the channel information, it is necessary to transmit a signal that is known to both the transmitter and the receiver. That is, when a signal known at the receiving end is received through a channel, a method of finding information of the channel with distortion degree of the signal is mainly used. In this case, a signal known to both a transmitting side and a receiving side is referred to as a reference signal or It is called a pilot signal.

In the past, when a transmitting end transmits a packet to a receiving end, one transmitting antenna and one receiving antenna have been used. However, in recent years, most mobile communication systems employ multiple transmission antennas and multiple reception antennas to improve transmission and reception data efficiency. When transmitting or receiving data using multiple antennas in order to increase capacity and improve communication performance at a transmitting end or a receiving end of a mobile communication system, a separate reference signal exists for each transmitting antenna. The receiving end can receive a signal transmitted from each transmitting antenna well by using a known reference signal for each transmitting antenna.

In a mobile communication system, a reference signal can be classified into two types according to its purpose. Reference signals include those used for channel information acquisition and data demodulation. In the former, since the UE can acquire downlink channel information, it needs to be transmitted over a wide band, and even a UE that does not receive downlink data in a specific subframe can receive and measure the reference signal. Should be In addition, the channel measurement reference signal may be used for the measurement of handover. The latter is a reference signal transmitted together with a corresponding resource when the base station transmits a downlink signal, and the terminal can estimate the channel by receiving the reference signal, and thus can demodulate the data. Such a demodulation reference signal should be transmitted to an area where data is transmitted.

7A and 7B illustrate reference signal patterns in a 3GPP LTE system as an example of a mobile communication system, and FIG. 7A illustrates reference signal patterns when a normal CP is applied. FIG. 7B is a diagram illustrating a reference signal pattern when extended CP is applied.

In the 3GPP LTE release-8 system, which is an example of a mobile communication system, two types of downlink reference signals are defined for unicast service. Common reference signal (CRS) and dedicated reference signal (DRS) used for data demodulation (corresponding to UE-specific reference signal) There are two reference signals called. In the LTE Release-8 system, UE-specific reference signals are used only for data demodulation, and CRS is used for both purposes of channel information acquisition and data demodulation. This CRS is a cell-specific reference signal, and the base station transmits the CRS every subframe over a wideband. In a cell-specific CRS, reference signals for up to four antenna ports are transmitted according to the number of transmit antennas of a base station.

As shown in (a) and (b) of FIG. 7, CRSs (1, 2, 3, and 4) for four antenna ports represent R0, R1, R2, and R3, which are reference signals for each antenna port, respectively. ) Is allocated so that time-frequency resources do not overlap in 1RB. When a CRS is mapped to a time-frequency resource in an LTE system, a reference signal for one antenna port on a frequency axis is mapped and transmitted to one RE per 6 REs. Since one RB consists of 12 REs on the frequency axis, two REs per RB are used for one antenna port.

As shown in FIGS. 7A and 7B, DRS (shown as “D”) is supported for single-antenna port transmission of the PDSCH. The terminal may receive information about whether or not there is a UE-specific RS from a higher layer. If data demodulation is required, a UE-specific RS is transmitted to the terminal through the resource element. On the other hand, the RS mapping rule to the resource block (RS) can be represented by the following equations (12) to (14). Equation 12 is an equation for representing a CRS mapping rule. Equation 13 is an equation for representing a mapping rule of a DRS to which a normal CP is applied, and Equation 14 is an equation for representing a mapping rule of a DRS to which an extended CP is applied.

, n_s,

는 각각 하향링크에 할당된 RB의 수, 슬롯 인덱스의 수, 셀 ID의 수를 나타낸다. RS의 위치는 주파수 도메인 관점에서 V_shift 값에 따라 달라진다.In Equations 12 to 14, k and p represent subcarrier indexes and antenna ports, respectively.

, n _s ,

Denotes the number of RBs, the number of slot indices, and the number of cell IDs, respectively. The position of RS depends on the value of V _{shift in} terms of frequency domain.

The 3GPP LTE-A system, which is the standard for the next generation mobile communication system, is expected to support CoMP (Coordinated Multi Point) and Multi User-MIMO (MU-MIMO) methods, which were not supported in existing systems, to improve data rates. Here, the CoMP system refers to a system in which two or more base stations or cells cooperate with each other to communicate with the terminal in order to improve communication performance between the terminal and the base station (cell or sector) in the shadow area.

CoMP can be classified into cooperative MIMO type joint processing (CoMP-Joint Processing, CoMP-JP) and cooperative scheduling / beamforming (CoMP-CS / CB) through data sharing.

In the case of downlink, in a joint processing (CoMP-JP) scheme, the UE may simultaneously receive data from each base station performing CoMP and may improve reception performance by combining signals received from each base station. . In contrast, in the cooperative scheduling / beamforming scheme (CoMP-CS), the terminal may receive data through one base station through beamforming instantaneously.

In the case of uplink, in each joint processing (CoMP-JP) scheme, each base station may simultaneously receive a PUSCH signal from the terminal. In contrast, in a cooperative scheduling / beamforming scheme (CoMP-CS), only one base station receives a PUSCH, where the decision to use the cooperative scheduling / beamforming scheme is determined by the cooperative cells (or base stations). .

In the MU-MIMO technology, the base station allocates each antenna resource to another terminal, and selects and schedules a terminal capable of a high data rate for each antenna. The MU-MIMO scheme is a technique for improving system throughput.

8 illustrates an example of an uplink subframe configuration including an SRS symbol.

Referring to FIG. 8, a sounding reference signal (SRS) is not related to uplink data and / or control information transmission and is mainly used to evaluate channel quality to enable frequency-selective scheduling on uplink. . However, SRS may also be used for other purposes, such as providing various functions for the recently unscheduled terminal or improving power control. SRS is a reference signal used for uplink channel measurement, and is a pilot signal transmitted by each terminal to a base station, and is used by the base station to estimate a channel state from each terminal to the base station. The channel for transmitting the SRS may have a different transmission bandwidth and transmission period for each terminal according to each terminal state. Based on the channel estimation result, the base station may determine which UE's data channel is scheduled for every subframe.

Assuming that the radio channel is in a reciprocal relationship between uplink and downlink, the SRS can be used to estimate downlink channel quality. This assumption is valid in a time division duplex (TDD) system in which uplink and downlink share the same frequency domain and are separated in the time domain. The subframe in which the SRS is transmitted by the terminal in the cell may be indicated by cell-specific broadcast signaling. A 4-bit cell-specific 'srssubframeConfiguration' parameter indicates a set of 15 possible subframes in which an SRS can be transmitted within each radio frame. This configuration provides flexibility in adjusting SRS overhead. As shown in FIG. 9, the UE can transmit the SRS through the last SC-FDMA symbol in the configured subframe.

Accordingly, the SRS and the demodulation reference signal (DM-RS) are located in different SC-FDMA symbols in a subframe. Sounding reference signals of various terminals transmitted in the last SC-FDMA of the same subframe may be distinguished according to frequency positions. Since PUSCH data of the UE is not transmitted through an SC-FDMA symbol designed for SRS, in the worst case, 7% sounding overhead is generated by having an SRS symbol in every subframe.

)이다. 여기서

는 SRS 시퀀스이다.The SRS is generated by a constant Amplitude Zero Auto Correlation (CAZAC) sequence and the like, and the sounding reference signals transmitted from various terminals are CAZAC sequences having different cyclic shift values (α) according to Equation 15 below. (

)to be. here

Is an SRS sequence.

는 상위 계층에 의하여 각 단말에 설정되는 값으로, 0 내지 7 사이의 정수 값을 갖는다. 하나의 CAZAC 시퀀스로부터 순환 천이를 통하여 발생된 CAZAC 시퀀스들은 각자 자신과 다른 순환 천이 값을 갖는 시퀀스들과 영의 상관 값(zero-correlation)을 갖는 특성이 있다. 이러한 특성을 이용하여 동일한 주파수 영역의 SRS들은 CAZAC 시퀀스 순환 천이 값에 따라 구분될 수 있다. 각 단말의 SRS는 기지국에서 설정하는 파라미터에 따라 주파수 상에 할당된다. 단말은 상향링크 데이터 전송 대역폭 전체로 SRS를 전송할 수 있도록 사운딩 참조신호의 주파수 호핑(hopping)을 수행한다. here

Is a value set for each terminal by a higher layer and has an integer value between 0 and 7. CAZAC sequences generated through a cyclic shift from one CAZAC sequence have a characteristic of having zero-correlation with sequences having a cyclic shift value different from itself. Using these characteristics, SRSs in the same frequency domain may be classified according to CAZAC sequence cyclic shift values. The SRS of each terminal is allocated on the frequency according to a parameter set by the base station. The terminal performs frequency hopping of the sounding reference signal to transmit the SRS over the entire uplink data transmission bandwidth.

As mentioned above, in the 3GPP LTE Release 8/9 system, the SRS transmission of the terminal only supports periodic SRS transmission, through which the base station can estimate the uplink channel quality of each terminal. In this case, the channel estimated by the base station is used for functions such as frequency dependent scheduling, link level adaptation, timing estimation, and UL power control. . The base station transmits the SRS uplink configuration to each terminal through UE-specific or cell-specifically through higher layer signaling (eg, RRC signaling) through SRS parameters. I can send it. The base station may inform the terminal of the SRS uplink configuration information as a type of an SRS uplink information element (Information Element) message as shown in Table 4 below.

Table 5 below shows SRS configuration parameters included in the SoundingRS-UL-Config information element message type in Table 4 above.

Referring to Table 4 and Table 5, SRS configuration information (SRS configuration information) that the base station informs the terminal is an SRS configuration parameter srsBandwidthConfiguration parameter, srsSubframeConfiguration parameter, srsBandwidth parameter, frequencyDomainPosition parameter, SrsHoppingBandwidth parameter, duration parameter, srsConfigurationIndex parameter, transmissionComb It may include a parameter. The srsBandwidthConfiguration parameter indicates the maximum SRS bandwidth information in the cell, and the srsSubframeConfiguration parameter indicates the subframe set information for the UE to transmit the SRS in the cell. The base station may inform the terminal of the srsSubframeConfiguration parameter by cell-specific signaling. As shown in Table 4, the base station transmits the srsSubframeConfiguration parameter to the UE in 4-bit size (sc0, sc1, sc2, sc3, sc4, sc5, sc6, sc7 sc8 sc9 sc10, sc11, sc12, sc13, sc14, sc15). Can signal The srsBandwidth parameter indicates the SRS transmission bandwidth of the UE, the frequencyDomainPosition parameter indicates the position of the frequency domain, the SrsHoppingBandwidth parameter indicates the SRS frequency hopping size, the duration parameter indicates whether it is one SRS transmission or periodic SRS transmission, and the srsConfigurationIndex parameter indicates the SRS Periodicity (Periodicity) and subframe offset (for example, indicates a time unit from the first subframe of the frame to the first SRS transmitted), the transmissionComb parameter indicates a transmission comb offset.

The base station may inform the terminal of the srsBandwidthConfiguration parameter and the srsSubframeConfiguration parameter by cell-specific signaling.In contrast, the base station may specify the srsBandwidth parameter, the frequencyDomainPosition parameter, the SrsHoppingBandwidth parameter, the duration parameter, the srsConfigurationIndex parameter, and the transmissionComb parameter for each UE. This can be informed via -specific) signaling.

The 3GPP LTE Release 10 system supports aperiodic SRS transmission for more adaptive uplink channel quality estimation and efficient SRS resource usage than the existing system. A method of triggering the aperiodic SRS transmission is still under discussion, and as an example, the base station may trigger by a DL / UL grant in the PDCCH. That is, the base station may transmit through a DL grant or a UL grant including an aperiodic SRS transmission triggering indicator for triggering aperiodic SRS transmission of the UE, or may be defined and transmitted in a new message format. In the present invention, a message for triggering aperiodic SRS transmission of the UE will be described below based on this as aperiodic SRS triggering grant (or aperiodic SRS triggering indicator, etc.).

In the present invention, the base station may give the terminal information about multiple aperiodic SRS configurations through higher layer signaling. A plurality of aperiodic SRS configuration information transmitted by a base station includes a subframe index information from which an aperiodic SRS distanceing grant is received or a temporal relationship between a reception subframe of an aperiodic SRS triggering grant and a corresponding aperiodic SRS transmission subframe. For example, information about a resource for aperiodic SRS transmission may be included. The present invention proposes a method in which the UE selectively applies a plurality of aperiodic SRS configurations. In particular, the UE configures the aperiodic SRS by using the subframe index information from which the aperiodic SRS distanceing grant is received or the time relationship between the reception subframe of the aperiodic SRS triggering grant and the corresponding aperiodic SRS transmission subframe. ) Can be adaptively switched.

Here, the number of aperiodic SRS configurations differs depending on the subframe index classification criteria at the time of arrival of the aperiodic SRS triggering grant or the definition of the time relationship between the receiving subframe of the aperiodic SRS triggering grant and the corresponding aperiodic SRS transmission subframe. Can be. The scheme proposed in the present invention does not require additional signaling overhead for aperiodic SRS configuration switching, and also copes with the SRS coverage problem and co-channel through adaptive aperiodic SRS configuration switching. It is possible to efficiently solve the uplink signal interference problem of HetNet (Heterogeneous Network).

First, as a resource for transmitting the aperiodic SRS of the proposed scheme, a cell-specific periodic SRS resource and a terminal-specific aperiodic resource and a terminal-specific for each cell defined in a 3GPP LTE Release 8/9 system (UE-specific) Reuse of periodic SRS resources may be considered. Therefore, this method has less overhead and needs more efficient use of SRS resources than signaling methods for defining new additional aperiodic SRS resources.

Aperiodic SRS configurations transmitted by the base station through higher layer signaling may be variously defined by having different values such as SRS bandwidth, comb, hopping bandwidth, starting physical resource block (PRB) allocation, and the like.

The proposed scheme not only determines whether aperiodic SRS is transmitted or not through aperiodic SRS triggering grant, but also enables the UE to adaptively switch a plurality of aperiodic SRS configurations to further change the uplink channel state between the base station and the UE. There is an advantage to be able to respond efficiently. In particular, in a situation such as HetNet, an appropriate aperiodic SRS configuration may vary depending on the location of the terminal. To cover this, the base station provides the terminal with information about the resources of the plurality of aperiodic SRS configurations and the aperiodic SRS configuration in addition to the plurality of aperiodic SRS configurations, and the processor 255 of the terminal appropriately selects one of them. It needs to work. For example, the UE may be bound to a subframe in which the PDCCH is descended according to a timing at which the PDCCH including an UL grant (for example, an UL grant triggering an aperiodic SRS transmission or an UL grant triggering a PUSCH transmission) comes down ( tied) Aperiodic SRS configuration may be used.

Hereinafter, aperiodic SRS transmission timing of the UE will be described. Assuming that the UE has received an aperiodic SRS triggering grant in subframe n (ie, a subframe having a subframe index of n) of a specific frame, the aperiodic SRS transmission time point of the UE is, for example, the nearest in subframe n. It may be the cell-specific periodic SRS subframe or the closest cell-specific periodic SRS subframe after subframe n + 3. In addition to the cell-specific periodic SRS resource, the UE may perform aperiodic SRS transmission through the UE-specific aperiodic SRS resource and the UE-specific periodic SRS resource. However, it is not necessarily limited thereto.

In addition, when the non-periodic SRS transmission time of the different terminals overlap, and the available aperiodic SRS resources are insufficient, considering the factors such as the aperiodic SRS bandwidth of each terminal, the transmission period of the periodic SRS more than the aperiodic SRS transmission More priorities can be given.

9A and 9B illustrate examples of subframes for cell-specific periodic SRS transmission and examples of subframes for UE-specific periodic SRS transmission, respectively.

Referring to FIG. 9A, the base station may configure a periodic SRS subframe (subframes 1, 3, 5, 7, 9) (subframe region hatched in FIG. 9A) as a cell-specific periodic SRS configuration.

Referring to FIG. 9B, a UE-specific periodic SRS configuration is shown. The base station may allocate some sets of UE-specific periodic SRS subframes to specific UEs in a subframe set composed of cell-specific periodic SRS subframes. In FIG. 9B, as an example, the base station allocates a periodic SRS subframe (subframes 1, 5, 9) to a specific terminal at a 4 ms period as a UE-specific periodic SRS configuration. In this case, a specific UE allocated with a UE-specific periodic SRS subframe from the base station transmits a periodic UE-specific SRS in subframes having subframe indexes 1, 5, and 9 (subframe regions hatched in dots in FIG. 9B). Can be.

10A, 10B, and 10C illustrate an example of an operation of dynamically selecting a plurality of SRS configurations using a time relationship between a subframe receiving an aperiodic SRS triggering grant and a corresponding aperiodic SRS transmission subframe, respectively. Indicates.

10A, 10B, and 10C, the base station configures subframes 1, 3, 5, 7, and 9 as cell-specific periodic SRS subframes, and subframes 1, 5, and 9 are UE-specific periodic for a specific UE. Assume that it is configured as an SRS subframe.

The base station may set a plurality of aperiodic SRS configurations and inform the terminal of this. These aperiodic SRS configurations are referred to as a first aperiodic SRS configuration and a second aperiodic SRS configuration, respectively. The information about the plurality of aperiodic SRS configurations is informed by the base station through the higher layer signaling. The information about the aperiodic SRS configuration may include information about a time point at which the UE transmits the aperiodic SRS and information about resources for the aperiodic SRS transmission. In particular, the time point at which the UE transmits the aperiodic SRS is an example of the closest (or fast) cell-specific periodic SRS subframe or subframe n + 3 after receiving the aperiodic SRS triggering grant. It may be in a cell-specific periodic SRS subframe cell coming soon. In addition, the aperiodic SRS may be transmitted through the UE-specific aperiodic SRS resource and the UE-specific periodic SRS resource as well as the cell-specific periodic SRS resource. In the present invention, as an example, the aperiodic SRS configuration assumes that the time point at which the UE transmits the aperiodic SRS is set to the cell-specific periodic SRS subframe closest to the subframe (subframe n) receiving the aperiodic SRS triggering grant. Will be explained. In addition, as shown in FIG. 9A, the cell-specific periodic SRS transmission subframe is assumed to be set to a period of 2 ms as an example.

The second aperiodic SRS configuration is to transmit aperiodic SRS in subframe n + 2 with respect to the aperiodic SRS triggering grant received by the UE in subframe n (n = 1, 2,...). The first aperiodic SRS configuration is for the UE to transmit aperiodic SRS in subframe n + 2 for the aperiodic SRS triggering grant received in subframe n + 1. As such, the processor 255 of the terminal may select a specific SRS configuration among the plurality of SRS configurations based on a time relationship between a subframe receiving the aperiodic SRS triggering grant and the corresponding aperiodic SRS transmission subframe. The selected SRS configuration operation can be performed. Here, as an example, it is assumed that in one 3GPP LTE and LTE-A system, one frame includes 10 subframes, and an index of each subframe included in one frame is assigned from 1 to 10.

Referring to FIG. 10A, as a second aperiodic SRS configuration, a time relationship between a subframe receiving an aperiodic SRS triggering grant and a corresponding aperiodic SRS transmission subframe (ie, a sub receiving an aperiodic SRS triggering grant) If the frame and the index difference between the corresponding aperiodic SRS transmission subframe) is 2, the UE subframes the aperiodic SRS with respect to the aperiodic SRS triggering grant received in subframe n (n = 1, 2, ...). Transmit at n + 2 (in this case, the time difference between when the aperiodic SRS triggering grant is received and when the aperiodic SRS is transmitted is 2), where the partial band (eg, part on the frequency axis of subframe n + 2) Band). That is, if the terminal is configured to receive the aperiodic SRS transmission triggering grant in subframe 1 and transmit the aperiodic SRS in subframe 3, the terminal may transmit the aperiodic SRS through the sub-band 1010 of subframe 3. have. Similarly, if the terminal is configured to receive the aperiodic SRS transmission triggering grant in subframe 5 and transmit the aperiodic SRS in subframe 7, the terminal may transmit the aperiodic SRS over the sub-band 1020 of subframe 7. have.

In contrast, referring to FIG. 10B, as a first aperiodic SRS configuration, a time relationship (ie, aperiodic SRS triggering grant) between a subframe receiving an aperiodic SRS triggering grant and an aperiodic SRS transmission subframe corresponding thereto is determined. If the difference between the indexes of the received subframe and the corresponding aperiodic SRS transmission subframe) is 1, the UE decrements the aperiodic SRS triggering grant received in the subframe n + 1 (n = 1, 2, ...). The periodic SRS may be transmitted in subframe n + 2, and may be configured to be transmitted through the entire band (for example, the entire band on the frequency axis of subframe n + 2) 1030 and 1040.

Here, the partial-band SRS transmission operation means that the terminal transmits the SRS using only a partial band in the band of the subframe allocated for SRS transmission, and the full-band SRS transmission operation refers to the terminal for SRS transmission. The transmission of the SRS using the entire band in the band of the allocated subframe.

Full-band aperiodic SRS transmission may be selected mainly when the uplink channel condition between the base station and the terminal is good, for example, using the same transmission band as the terminal adjacent to the base station or the macro base station (MeNB). A macro terminal (MUE) far from the home base station (HeNB) may perform a full-band aperiodic SRS transmission operation. On the other hand, the partial-band aperiodic SRS transmission operation may be selected when the uplink channel condition between the base station and the terminal is not good, for example, the same transmission band as the terminal or the macro base station located at the cell edge. A macro terminal transmitting an uplink signal located in or near an area of a home base station that uses the UE may perform a partial-band aperiodic SRS transmission operation.

The processor 255 of the terminal adaptively switches the proposed aperiodic SRS configuration and the second aperiodic SRS configuration flexibly based on the current network conditions, communication environment, aperiodic SRS triggering grant time, etc. It can efficiently cope with the coverage problem and the uplink signal interference problem of co-channel HetNet.

In particular, the second aperiodic SRS configuration shown in FIG. 10A is a transmission scheme through frequency hopping partial-bands 1010 and 1020 in a partial-band aperiodic SRS transmission scheme. In this case, the UE concentrates its transmission power on a part of the entire SRS resource region, thereby effectively solving the SRS coverage problem.

According to the first aperiodic SRS configuration shown in FIG. 10B, if the UE is configured to receive the aperiodic SRS transmission triggering grant in subframe 2 and transmit the aperiodic SRS in subframe 3, the UE is configured to receive the entire subframe 3 in subframe 3. Aperiodic SRS may be transmitted through the band 1030. Similarly, if the terminal is configured to receive the aperiodic SRS transmission triggering grant in subframe 6 and transmit the aperiodic SRS in subframe 7, the terminal can transmit the aperiodic SRS over the full-band 1040 of subframe 7. have.

Although the aperiodic SRS configuration shown in FIG. 10C is set to a partial-band aperiodic SRS transmission scheme like the second aperiodic SRS configuration, an uplink signal of a co-channel HetNet It can be set in a non-frequency-hopping manner to solve the interference problem. Here, the uplink signal transmission bands of the macro terminal and the home terminal are designated as fixed partial-bands 1050 and 1060 that are orthogonal to each other.

In addition, the first aperiodic SRS configuration and the second aperiodic SRS configuration may be defined by any one of the combinations of FIGS. 10A and 10B or the combinations of FIGS. 10B and 10C, respectively, and the base station may define defined combination information and / or The selected combination information can be delivered to the terminal through higher layer signaling.

FIG. 11 illustrates an aperiodic SRS operation when a subframe index classification at the time of arrival of an aperiodic SRS triggering grant is applied as another criterion.

Referring to FIG. 11, the base station allocates subframes 1, 3, 5, 7, and 9 to cell-specific periodic SRS subframes, and assigns subframes 1, 5, and 9 to terminal-specific periodic SRS subframes. Suppose you assigned it. According to the aperiodic SRS configuration shown in FIG. 11, when the processor 255 of the UE has an odd number of indexes of a subframe in which the aperiodic SRS triggering grant arrives among a plurality of SRS configurations (n = 1, 3, 5,? (9), (in this case, when the subframe index is indexed to the first subframe of 1), the first aperiodic SRS configuration may be selected, and the index of the subframe in which the aperiodic SRS triggering grant arrives. If is an even number, the second aperiodic SRS configuration may be selected.

For example, when the UE receives the aperiodic SRS transmission triggering grant in subframe 1, which is an odd index subframe, the full-band 1110 may be determined in subframe 3, which is the cell-specific periodic SRS subframe that is closest to subframe 1. Through the aperiodic SRS can be transmitted. In addition, when the UE receives the aperiodic SRS transmission triggering grant in subframe 6 which is an even index subframe, the UE receives the aperiodic SRS through the sub-band 1120 in subframe 7 which is the closest cell-specific periodic SRS subframe. Can be transmitted.

As another embodiment of FIG. 11, when the UE-specific periodic SRS subframe index allocated by the base station to a specific UE in a specific frame is n (eg, n = 1, 5, 9). In this case, a subframe in which an aperiodic SRS triggering grant is received is divided into a subframe at n-4 or a subframe other than n-4. Here, the definition of the n-4 time point may be variously designated as another value. In FIG. 11, when the UE receives an aperiodic SRS triggering grant in a subframe having subframe index 1 (ie, the first subframe (subframe 1)), subframe 1 is a subframe having subframe index 5 (ie, subframe index 5). Since the subframe corresponds to a subframe at n-4 of subframe 5), the UE is then full-band in subframe 3, which is the closest (or fast) cell-specific periodic SRS subframe that follows subframe 1. The SRS transmission operation may be performed through the at 1110. In addition, when the UE receives the aperiodic SRS triggering grant in a subframe having the subframe index 6 (ie, the subframe 6), the subframe 6 is n-4 of the subframe having the subframe index 9 (ie, the subframe 9). Since the terminal is not a subframe of the view, the UE may perform an SRS transmission operation through the sub-band 1120 in subframe 7, which is a cell-specific periodic SRS subframe closest to subframe 6.

As such, when the UE receives the aperiodic SRS triggering grant in a subframe at n-4 time points, the UE operates in full-band aperiodic sounding, that is, operates in the third aperiodic SRS configuration. It may operate with partial-band aperiodic sounding, ie with the fourth aperiodic SRS configuration. Here, the content common to the first and second aperiodic SRS configuration uses a scheme in which the UE transmits the aperiodic SRS through the cell-specific periodic SRS subframe closest to the subframe in which the aperiodic SRS triggering grant is received. Is that. The third and fourth aperiodic SRS configurations may be set by the base station, and the base station may inform the terminal through higher layer signaling.

12A and 12B are diagrams illustrating an example of a subframe of an aperiodic SRS configuration, respectively.

Referring to FIG. 12A, as a fifth aperiodic SRS configuration, the base station may configure the terminal to transmit the aperiodic SRS through the sub-bands of subframes having subframe indexes 1, 5, and 9. As shown in FIG. 12A, in the fifth aperiodic SRS configuration, the SRS transmission period and the subframe offset are 4 ms and 0 ms, respectively, so that the UE may transmit the SRS through partial bands in subframes 1, 5, and 9.

In addition, referring to FIG. 12B, the base station may configure the terminal to transmit the aperiodic SRS through the full-band of the subframes having subframe indexes 3 and 7 as the sixth aperiodic SRS configuration. As shown in FIG. 12B, in the sixth aperiodic SRS configuration, the SRS transmission period and the subframe offset are 4 ms and 2 ms, respectively, so that the UE may transmit the SRS through the entire band in subframes 3 and 7. In this case, since the resources for the aperiodic SRS transmission subframes in the fifth and sixth aperiodic SRS configurations reuse the resources for the cell-specific periodic SRS transmission, the period of the subframe in which the aperiodic SRS is transmitted is the cell- It may be specified as a multiple of the specific periodic SRS subframe period or the same value. Such fifth and sixth aperiodic SRS configuration information (including information on SRS transmission subframes according to these SRS configurations) may be informed by the base station to the terminal through higher layer signaling.

FIG. 13 is a diagram for describing switching of the aperiodic SRS configuration operation according to the aperiodic SRS configuration of FIGS. 12A and 12B and a time point when the UE receives the aperiodic SRS triggering grant.

When the UE performs aperiodic SRS transmission through the closest cell-specific periodic SRS subframe in the subframe receiving the aperiodic SRS triggering grant, the SRS of the closest cell-specific periodic SRS subframe transmitting the aperiodic SRS Depending on the configuration, aperiodic SRS transmission can be different.

For example, as shown in FIG. 13, the base station allocates subframes 1, 3, 5, 7, and 9 as a periodic SRS transmission subframe as a cell-specific periodic SRS configuration. In addition, the base station may allocate subframes 1, 5, and 9 as UE-specific periodic SRS transmission subframes. When the UE receives the aperiodic SRS triggering grant in subframe 1, the UE may transmit the aperiodic SRS through subframe 3, which is a cell-specific periodic SRS subframe closest to subframe 1. In this case, since the closest cell-specific aperiodic SRS subframe 3 when the aperiodic SRS triggering grant is received corresponds to a subframe configured with the sixth aperiodic SRS configuration in FIG. 12B, the UE is the entire subframe 3. Aperiodic SRS may be transmitted through the full-band 1310. In another embodiment, similar to the third aperiodic SRS configuration, subframe 1 in which the UE receives the aperiodic SRS triggering grant corresponds to n-4 time points for subframe 5 which is a cell-specific periodic SRS subframe. Since the UE is a subframe, the UE can transmit the aperiodic SRS through the full-band 1310 of subframe 3.

In addition, when the UE receives the aperiodic SRS triggering grant in subframe 8, the UE may transmit the aperiodic SRS through subframe 9, which is the cell-specific periodic SRS subframe closest to subframe 8. In this case, since the cell-specific aperiodic SRS subframe 9 that is closest to the time of receiving the aperiodic SRS triggering grant is a subframe configured with the fifth aperiodic SRS configuration illustrated in FIG. 12A, the UE is part of subframe 9. Aperiodic SRS may be transmitted through the band 1320. In another embodiment, similar to the fourth SRS configuration, since the subframe 8 that has received the aperiodic SRS triggering grant does not correspond to the subframe that is n-4 time points for the subframe 3, the UE is part of the subframe 8 Aperiodic SRS may be transmitted over the band 1320. In addition, subframe 9 is allocated to a UE-specific periodic SRS subframe to perform periodic SRS transmission by default. However, when the UE overlaps with a non-periodic SRS transmission time point, the UE cancels the periodic SRS and transmits the aperiodic SRS. do.

14A and 14B are diagrams for describing fallback aperiodic SRS transmission, respectively.

The seventh aperiodic SRS configuration and the eighth aperiodic SRS configuration illustrated in FIGS. 14A and 14B, respectively, correspond to a time between receiving aperiodic SRS transmission triggering granule (for example, a subframe index) and a time point for transmitting aperiodic SRS. The terminal is configured to transmit the aperiodic SRS through the full-band or partial-band using a time difference.

The base station may allocate the SRS subframe as shown in FIG. 14A as the seventh aperiodic SRS configuration. The seventh aperiodic SRS configuration is a configuration for transmitting the aperiodic SRS over the entire band similarly to the aperiodic SRS triggering scheme shown in FIG. 10B (ie, the first SRS aperiodic configuration scheme). However, in the seventh aperiodic SRS configuration, the existing aperiodic SRS resources through the full-band are referred to as 'reconfigured full-band aperiodic SRS resources' 1410 and 'fallback aperiodic SRS resources' ( 1415), which is a non-periodic SRS configuration.

As shown in FIG. 14A, the fallback aperiodic SRS resource 1415 may use some reduced resource block (RB) region 1415 of the allocated full-band aperiodic SRS resource 1410. Alternatively, the fallback aperiodic SRS resource 1415 may be previously defined as a resource region that is disjoint from the full-band aperiodic SRS resource.

The methods represented by the fallback aperiodic SRS resources in FIGS. 14A and 14B are the two fallback aperiodic SRS resource allocation methods mentioned above ('reconfigured full-band aperiodic SRS resources' and 'fallback aperiodic'). SRS resources'), not just any one, but both. In addition, the fallback aperiodic SRS resource 1415 occupies a relatively smaller area than the reconstructed full-band aperiodic SRS resource 1410, and the fallback aperiodic SRS resources 1415 and 1425 for each SRS transmission subframe. May be assigned a frequency hopping pattern.

Switching between the reconstructed full-band aperiodic SRS resource and the fallback aperiodic SRS resource requires the processor 255 of the terminal to successfully transmit the aperiodic SRS on the reconstructed full-band aperiodic SRS resource 1410. Compare the amount with the amount of power currently available, and if sufficient, allow the SRS to be sent over the reconfigured full-band aperiodic SRS resource 1410, and if not, fall back to the fallback aperiodic SRS resource 1415 to Send it. In this case, since the switching to the fallback aperiodic SRS resource 1415 is performed by the determination and determination of the processor 255 of the terminal, the base station needs to find the resource region to which the aperiodic SRS is transmitted through blind decoding. The processor 255 of the terminal determines whether the transmission power is sufficient, and if it is determined that the transmission power is sufficient, the terminal determines that the full-band aperiodic SRS resource 1410 reconstructed in subframe 3 is present. SRS can be transmitted through the SRS. In addition, if the UE receives the aperiodic SRS triggering grant in subframe 6 and the processor 255 of the UE determines that the transmission power is insufficient, the UE switches to the fallback aperiodic SRS transmission scheme in subframe 7 to fallback aperiodically. Aperiodic SRS may be transmitted through the SRS resource 1415. This operation can also be applied to the partial-band aperiodic sounding scheme.

The base station may configure an SRS subframe as shown in FIG. 14B as an eighth aperiodic SRS configuration. Referring to FIG. 14B, an eighth aperiodic SRS configuration operates by dividing a partial-band aperiodic SRS resource into a reconfigured partial-band aperiodic SRS resource 1430 and a fallback aperiodic SRS resource 1440. Aperiodic SRS transmission scheme is shown. Here, the aperiodic SRS triggering method follows the same method as the method used in FIG. 10A (that is, the second aperiodic SRS configuration) described above, and the fallback aperiodic SRS resource 1440 is partially-band aperiodic as shown in FIG. 14B. It may be defined in advance as a resource region that is disjoint from the SRS resource 1430. Alternatively, a partial reduced RB region of the partial-band aperiodic SRS resource allocated to the fallback aperiodic SRS resource 1440 may be used.

In FIG. 14B, if the UE receives the aperiodic SRS triggering grant in subframe 1 and the processor 255 of the UE determines whether the transmission power is sufficient, the UE determines that the transmission power is sufficient, and the UE determines the partial-band aperiodic SRS with sufficient transmission power. The SRS transmission may be successfully performed through the resource 1430. In addition, if the UE receives the aperiodic SRS triggering grant in subframe 5 and the processor 255 of the UE determines that the transmission power is insufficient, the UE switches to the fallback aperiodic SRS scheme to fallback aperiodic SRS of the subframe 7. Aperiodic SRS may be transmitted through the resource 1450. In this case, the UE may perform aperiodic SRS transmission through the fallback aperiodic SRS resource 1450. Accordingly, the UE can efficiently solve the SRS coverage problem by adaptively falling back an aperiodic SRS resource. When the UE transmits the aperiodic SRS through the fallback aperiodic SRS resource, the base station needs to find the resource region where the aperiodic SRS is transmitted through blind decoding.

Here, although the processor 255 of the terminal determines whether to switch by the fallback aperiodic SRS method is determined whether the power is sufficient, in addition, the serving cell from the neighbor cell neighboring cell is strong for a specific band When the UE is notified of neighbor cell interference information such as information causing interference, it may operate in a fallback aperiodic SRS scheme for the specific band. For example, if UE A located at the edge of neighbor cell A transmits SRS in a specific band of subframe 1, if this SRS uplink transmission acts as strong interference to cell B, cell B is uplinked. In consideration of the interference, signaling (for example, 1 bit) such as instructing the UE in the cell to transmit the aperiodic SRS through the fallback aperiodic SRS resource may be delivered. Then, the UE in the cell B may transmit the SRS through the fallback aperiodic SRS resource in subframe 1 based on this signaling. Cells A and B may exchange information related to such uplink interference through a backhaul, and may allocate SRS resources of UEs in a cell in consideration of uplink interference due to SRS transmission of neighbor cells.

15A is a diagram illustrating a cell-specific SRS subframe configuration and a configuration of cell-specific SRS resources, FIG. 15B is a diagram illustrating an SRS configuration in which cell-specific periodic SRS resources and cell-specific aperiodic SRS resources are multiplexed. 15C is a diagram illustrating an example of an aperiodic SRS subframe configuration.

First, referring to FIG. 15A, the base station configures the cell-specific SRS subframes into subframes 1, 3, 5, 7, and 9 every 2 ms according to a rule previously set for the cell-specific SRS subframes. SRS resources can be allocated. The UE may transmit an aperiodic SRS through a subframe in which cell-specific periodic SRS resources and cell-specific aperiodic SRS resources are multiplexed or aperiodic SRS subframes. .

15B and 15C, the base station multiplexes a 'cell-specific periodic SRS resource and aperiodic SRS resource, such as subframes 1, 5, and 9, among the cell-specific SRS subframes configured in FIG. 15A. Frame ”and“ aperiodic SRS subframes ”such as subframes 3 and 7. Here, the subframe in which the cell-specific periodic SRS resource and the aperiodic SRS resource are multiplexed is a method of dividing the cell-specific SRS resource into 'periodic SRS resource' 1510 and 'aperiodic SRS resource' 1520.

The cell-specific SRS resource division scheme divides into two regions orthogonal in the frequency domain (for example, two subbands) or separates the entire set of available comb and pairs of cyclic shifts. After dividing into two disjoint subsets, each may be allocated to a periodic SRS resource and an aperiodic SRS resource. As an example of the latter method, two usable combs are divided into full-band sounding and partial-band sounding purposes, and the eight cyclic shifts that can be combined with each comb are divided in half and the periodic SRS resource and It can be allocated as an aperiodic SRS resource.

For example, the UE A transmits aperiodic SRS through the aperiodic SRS resource 1520 in subframe 1, and at the same time, the UE B transmits the periodic SRS through the periodic SRS resource 1510 in subframe 1. have. That is, the aperiodic SRS of the terminal A and the periodic SRS of the terminal B may be multiplexed in subframe 1 and transmitted. In addition, one UE may transmit the non-periodic SRS and the periodic SRS by multiplexing in subframe 1, in which a different bandwidth is applied to the periodic SRS and the non-periodic SRS so that channel estimation of a specific bandwidth may be more efficient. can do.

Referring to FIG. 15C, the base station may allocate resources to the full-band 1530 for aperiodic SRS transmission in subframes 3 and 7 among the cell-specific SRS subframes configured in FIG. 15A.

As shown in FIGS. 15B and 15C, the base station may alternately allocate cell-specific SRS subframes allocated to subframes in which cell-specific periodic and aperiodic SRS resources are multiplexed and aperiodic SRS subframes, respectively. have. For example, the base station is configured to multiplex cell-specific periodic and aperiodic SRS resources in cell-specific SRS subframe 1, followed by cell-specific SRS subframe 3 as aperiodic SRS subframes, Cell-specific SRS subframe 5 that follows may be configured to multiplex cell-specific periodic and aperiodic SRS resources again (ninth aperiodic SRS configuration). The rules used here can be defined in various ways. In addition, the division of the periodic SRS resource and the non-periodic SRS resource shown in FIG. 15B is not limited to being divided as a result of using only one of the two cell-specific SRS resource partitioning methods mentioned above, and both SRS resource partitioning methods It may be divided into the result using.

Additionally, when aperiodic SRS transmission is required in a subframe in which cell-specific periodic SRS resources and aperiodic SRS resources are multiplexed, the terminal may transmit the SRS through a designated aperiodic SRS resource. Since the UE does not know when the aperiodic SRS triggering indicator (for example, grant) will come, the base station may predetermine and allocate resources for transmitting the aperiodic SRS of the UEs in advance. In the subframes in which cell-specific periodic and aperiodic SRS resources are multiplexed, periodic SRS transmission is determined as a basic scheme. However, in case of overlapping with aperiodic SRS transmission, the UE cancels periodic SRS transmission and aperiodic SRS transmission. May be performed first.

FIG. 16 illustrates a UE-specific periodic SRS subframe configuration.

The base station may allocate an SRS transmission subframe to a specific terminal as shown in FIG. 16 as a tenth SRS configuration. The tenth SRS configuration allocates UE-specific periodic SRS subframes in a 2 ms period in a specific frame. For example, subframes 1, 3, 5, 7, and 9 are allocated as UE-specific periodic SRS subframes in a specific frame. Some subframes among the UE-specific periodic SRS subframes may be configured as subframes in which cell-specific periodic SRS and aperiodic SRS resources are multiplexed, which is indicated by a dotted line in FIG. 16. In a subframe indicated by a dotted line in FIG. 16, cell-specific periodic SRS and aperiodic SRS resources are illustrated in a frequency division multiplexing scheme, but are not limited thereto. In subframes 1, 5, and 9, cell-specific periodic SRS and aperiodic SRS may be multiplexed and transmitted. For example, in subframes 1, 5, and 9, UE A may transmit periodic SRS and UE B may transmit aperiodic SRS. Or, in the subframes 1, 5, and 9, the terminal A may multiplex the periodic SRS and the aperiodic SRS in one subframe and transmit the same. The period of the periodic SRS subframe specifically allocated to each UE may be a multiple of the subframe period in which cell-specific periodic and aperiodic SRS resources are multiplexed or may be designated with the same value.

17A to 17C are diagrams for explaining an operation of dynamically selecting a plurality of SRS configurations using a time relationship between an aperiodic SRS triggering grant reception subframe and a corresponding aperiodic SRS transmission subframe, respectively.

Here, the terminal has two aperiodic SRS configurations, which are represented by an eleventh SRS configuration and a twelfth SRS configuration, respectively. In addition, it is assumed that the aperiodic SRS transmission time point of the UE is designated as the closest (or fast) cell-specific SRS subframe subsequent to the subframe receiving the aperiodic SRS triggering grant, and the period of the cell-specific SRS subframe is It was set to 2ms.

The base station may allocate an SRS subframe as shown in FIG. 17A as the eleventh SRS configuration. When the terminal receives the aperiodic SRS triggering grant in subframe n (eg, n = 5, 9), the processor 255 of the terminal may select the eleventh SRS configuration and according to the eleventh SRS configuration The UE may transmit the aperiodic SRS through the subbands 1710 and 1720 in subframe n + 2 (that is, n + 2 = 7, 1). In particular, in the eleventh SRS configuration, the partial bands 1710 and 1720 in which the UE transmits the aperiodic SRS are configured in the form of frequency hopping.

The base station may allocate the SRS subframe as shown in FIG. 17B as the twelfth SRS configuration. When the UE receives the aperiodic SRS triggering grant in subframe n (n = 2, 8), the processor 255 of the UE may select the 12th SRS configuration, and the UE may select the aperiodic SRS according to the 12th SRS configuration. Can be transmitted over the entire band in subframe n + 1 (that is, n + 1 = 3, 9).

Here, as an example, it is assumed that in one 3GPP LTE and LTE-A system, one frame includes 10 subframes, and an index of each subframe included in one frame is assigned from 1 to 10. When the time relationship between the subframe receiving the aperiodic SRS triggering grant and the subframe for transmitting the aperiodic SRS is 2, the index difference between the subframe index for receiving the aperiodic SRS triggering grant and the subframe index for the aperiodic SRS is 2, For example, as shown in FIG. 17A, when the UE receives an aperiodic SRS triggering grant in subframe 5, the processor 255 of the UE selects an eleventh SRS configuration, and subframe 7 according to the eleventh SRS configuration. In the sub-band 1710, the aperiodic SRS transmission operation can be performed. On the other hand, the time difference between the UE receiving subframe of the aperiodic SRS triggering grant and the subframe for transmitting the aperiodic SRS has an index difference between the subframe index for receiving the aperiodic SRS triggering grant and the subframe index for transmitting the aperiodic SRS is 1 For example, when receiving the aperiodic SRS triggering grant in subframe 8 as shown in FIG. 17B, the processor 255 of the terminal selects the twelfth SRS configuration and in full subband 9 in subframe 9. Aperiodic SRS transmission operation is performed. In subframe 9 of FIG. 17B, a resource in which an aperiodic SRS is transmitted is indicated by a dotted line 1740, but is actually transmitted through the entire band. That is, the aperiodic SRS may be divided into periodic SRS transmission, comb, cyclic shift, and the like, and may be transmitted together over the entire band.

In addition, when full-band or partial-band aperiodic SRS transmission is required in a subframe multiplexed with cell-specific periodic and aperiodic SRS, the UE may perform a configuration according to the first aperiodic SRS configuration through a designated aperiodic SRS resource. SRS transmission or SRS transmission according to the second aperiodic SRS configuration may be performed.

As shown in FIG. 17A, the partial-band aperiodic SRS resource may be allocated with a frequency hopping pattern (ie, allocated as in 1710 and 1720) to effectively solve the SRS coverage problem through diversity gain.

The base station may allocate an SRS subframe as shown in FIG. 17C as the thirteenth SRS configuration. The thirteenth aperiodic SRS configuration shown in FIG. 17C is an example of another partial-band aperiodic SRS configuration that is different from the SRS configuration of FIG. 17A and is a partial-band aperiodic SRS scheme that does not use a frequency hopping scheme. In the thirteenth aperiodic SRS configuration, partial-band aperiodic SRS transmission that does not use a frequency hopping scheme is configured. When the UE receives the aperiodic SRS triggering grant in subframe 5, the UE may transmit the aperiodic SRS through the partial band 1750 of subframe 7, which is the fastest subframe subsequent to subframe 5. In addition, when the UE receives the aperiodic SRS triggering grant in subframe 9, the UE may transmit the aperiodic SRS through the partial band 1760 of subframe 1 of the next frame subsequent to subframe 9. Partial-band aperiodic SRS transmission without frequency hopping is very effective in mitigating the uplink signal interference problem caused by using co-channel between heterogeneous networks.

FIG. 18 is a diagram for describing aperiodic SRS transmission corresponding to a case where a subframe index classification at the time of receiving an aperiodic SRS triggering grant of a terminal is applied as another criterion.

In FIG. 18, when the index of the subframe in which the UE receives the aperiodic SRS triggering grant is an odd number (eg, subframe 1 as shown in FIG. 18), the UE completes in subframe 3. Aperiodic SRS transmission operation can be performed through the band. Meanwhile, when the UE has an even index (eg, subframe 6 as shown in FIG. 18) of the reception subframe of the aperiodic SRS triggering grant, the UE performs a partial-band aperiodic SRS transmission operation in subframe 7. Can be performed.

In addition, as another embodiment with reference to FIG. 18, when a UE-specific periodic SRS subframe index allocated to a specific UE is n, a subframe in which the UE receives an aperiodic SRS triggering grant is determined. This method is divided into subframes at index n-4 and other subframes. Here, the definition of the subframe n-4 at index n-4 may be variously designated as another value.

When the UE receives the aperiodic SRS triggering grant at subframe n-4, the aperiodic SRS may be transmitted through the full-band of the periodic SRS subframe closest to the subframe n. On the contrary, when the UE receives the aperiodic SRS triggering grant in a subframe different in subframe n-4, the UE transmits the aperiodic SRS through the sub-band of the periodic SRS subframe closest to the subframe n. Can be. In both SRS configurations, a UE uses a method in which aperiodic SRS transmission is transmitted on a periodic SRS subframe closest to a subframe in which the aperiodic SRS triggering grant is received.

As shown in FIG. 18, for example, when the UE receives an aperiodic SRS triggering grant in subframe 1, the subframe 1 is a subframe of n-4 time points in subframe 5 (n = 5). May perform the operation of transmitting the aperiodic SRS over the full-band 1810. In addition, when the UE receives the aperiodic SRS triggering grant in subframe 6, the subframe 6 does not correspond to the subframe at the time of n-4 of subframe 9 (n = 9). In operation 1820, an aperiodic SRS is transmitted.

19A and 19B are diagrams illustrating an example of an aperiodic SRS subframe having an SRS configuration, respectively.

In FIG. 19A and FIG. 19B, a frame subsequent to the second frame exists, but the second frame is shown and described for convenience of description. As shown in FIG. 19A, the SRS configuration for transmitting the SRS through the partial-band may have an SRS transmission period and a subframe offset of 4 ms and 2 ms, respectively. The base station may configure subframes 3 and 7 of the first frame and subframes 1 and 5 of the second frame as SRS subframes through the partial-band. That is, the UE may transmit the SRS through the sub-bands in subframes 3 and 7 in the first frame and subframes 1 and 5 in the second frame subsequent to the first frame. As shown in FIG. 19B, in the SRS configuration for transmitting the SRS over the full-band, the SRS transmission period and the subframe offset may be set to 4 ms and 0 ms, respectively. The base station may configure subframes 1, 5, 9 of the first frame, subframe 3 of the second frame, etc. as SRS subframes over the full-band. The UE may transmit the SRS over the entire band in subframes 1, 5, subframe 9 of the first frame, and subframe 3 of the second frame subsequent to the first frame.

At this time, since the resources for the SRS transmission subframe in each SRS configuration reuses the resources for cell-specific periodic SRS transmission, the period of the subframe in which the aperiodic SRS is transmitted is a multiple of the cell-specific periodic SRS subframe period. It can be specified in the form or the same value. As such, information about a subframe for transmitting the SRS through the partial-band and a subframe for transmitting the SRS through the full-band may be previously set between the base station and the terminal and may be known in advance. You can also send it via.

FIG. 20 is a diagram for describing switching of the aperiodic SRS configuration operation according to the aperiodic SRS configuration of FIGS. 19A and 19B and a time point when the UE receives the aperiodic SRS triggering grant.

The base station allocates SRS resources to all-bands in subframes 1, 5, and 9, but may configure a subframe multiplexed with cell-specific periodic SRS resources and cell-specific aperiodic SRS resources. The base station divides the SRS resources in this multiplexed subframe into two orthogonal regions (e.g., two subbands), or separates the entire set of available combs and pairs of cyclic shifts. After dividing into two disjoint subsets, each may be allocated to a periodic SRS resource and an aperiodic SRS resource.

In FIG. 20, it is assumed that a UE determines a transmission time of an aperiodic SRS as a cell-specific SRS subframe closest to a subframe in which the aperiodic SRS triggering grant is received. As shown in FIG. 20, as an example, when the UE receives an aperiodic SRS triggering grant in subframe 2, the UE may perform non-subframe over subframe 3, which is a cell-specific SRS subframe that comes soonest in subframe 2. Periodic SRS may be transmitted. In this case, since the subframe 3 is configured as the SRS transmission subframe through the partial-band in FIG. 19A, the UE transmits the aperiodic SRS through the sub-band 2010 in the subframe 3. In addition, when the UE receives the aperiodic SRS triggering grant in subframe 8, the UE transmits the aperiodic SRS through the closest cell-specific SRS subframe 9. In this case, since the subframe 9 in which the SRS is transmitted is configured as a subframe transmitting the SRS through the full-band in FIG. 19B, the UE transmits the aperiodic SRS through the full-band 2020 in the subframe 9. 21A and 21B illustrate a new scheme of aperiodic SRS transmission in which some of the aperiodic SRS transmission resources are divided and used as fallback aperiodic SRS transmission resources.

Here, the fallback aperiodic SRS resource 2115 may use a portion of the reduced resource block (RB) of the allocated aperiodic SRS transmission resource 2110. Alternatively, the fallback aperiodic SRS resource may be divided into two subsets previously separated from the aperiodic SRS transmission resource and disjoint the entire set of resource regions, pairs of available combs and cyclic shifts. After dividing by, it may be defined by dividing into aperiodic SRS resources and fallback aperiodic SRS resources. The allocated fallback aperiodic SRS transmission resource illustrated in FIGS. 21A and 21B does not refer to only one of the two fallback aperiodic SRS transmission resource allocation schemes mentioned above, but includes both schemes.

The partial-band aperiodic SRS transmission scheme illustrated in FIG. 21A is a scheme of transmitting a full-band aperiodic SRS in a non-periodic SRS triggering scheme similar to FIG. 20. When the UE receives the aperiodic SRS triggering grant in subframe 2, the UE may transmit the aperiodic SRS through the sub-band 2110 of subframe 3, which is the cell-specific periodic SRS subframe closest to subframe 2. . When the UE receives the aperiodic SRS triggering grant in subframe 6, the UE may transmit the aperiodic SRS in subframe 7, which is the cell-specific periodic SRS subframe closest to subframe 6. In this case, the processor 255 of the terminal may switch to transmit the SRS through the fallback aperiodic SRS transmission resource 2120 due to insufficient transmission power or the like in subframe 7.

In addition, the full-band aperiodic SRS transmission shown in FIG. 21B is a full-band aperiodic SRS transmission scheme similar to that of FIG. 20. When the UE receives the aperiodic SRS triggering grant in subframe 3 according to the full-band aperiodic SRS transmission scheme illustrated in FIG. 21B, the UE corresponds to a cell-specific periodic SRS transmission subframe closest to subframe 3. In frame 5, the SRS may be transmitted. In this case, the UE may transmit the aperiodic SRS through the fallback aperiodic SRS resource 2130 in subframe 5. In addition, when the UE receives the aperiodic SRS triggering grant in subframe 8, the UE transmits the SRS through the entire band 2140 in subframe 9 corresponding to the cell-specific periodic SRS transmission subframe closest to subframe 8. Can be.

The SRS configuration information of FIG. 21A and FIG. 21B may inform the base station of the terminal through higher layer signaling.

So far, a method of transmitting aperiodic SRS by a UE in a system after 3GPP LTE Release 10 has been described. The purpose of introducing aperiodic SRS in the 3GPP LTE Release 10 system is to improve the quality of channel estimation of the base station and to perform channel estimation more accurately and adaptively while reducing the overhead of periodic SRS transmission.

As another embodiment of the present invention, when performing aperiodic SRS transmission by various aperiodic SRS triggering schemes, to increase the accuracy and efficiency of the channel estimation result of the base station obtained through the aperiodic SRS transmission of the terminal aperiodic It is newly proposed to use a method different from the periodic SRS transmit power control for the SRS transmit power control. The scheme proposed in the present invention can be applied to various aperiodic SRS duration environments.

 The existing SRS transmit power equation may be represented by Equation 16 below.

Here, i is a subframe index, and P _SRS (i) refers to SRS power transmitted in subframe i (that is, subframe of index i). In Equation 16, parameters that the base station determines by semi-statically determined by the upper layer signaling and informs the terminal and parameters that are dynamically determined and informed through the TPC (Transmit Power Control) command of the PDCCH Consists of.

,

,

,

,

는 기지국이 상위 계층 신호를 통해 단말에게 알려주며,

는 기지국이 PDCCH의 TPC command를 통해 단말에게 동적으로 알려준다.

은 SRS 전송을 위한 전력 옵셋값인 단말-특정 파라미터로서(예를 들어, 4 비트) 상위 레이어에서 반-고정적으로(semi-statically) 구성되는 값으로 기지국이 단말에게 시그널링해주는 값이다.

는 현재 PUSCH 파워 제어 조정 상태를 나타내는 값으로서, 현재의 절대값 또는 축적된 값으로 표현될 수 있다. α(j)는 상위 계층에서 기지국이 예를 들어 3 비트로 전송해 주는 셀-특정 파라미터로서 j=0 또는 1일 때, α∈{0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}이고, j=2일때, α(j)=1이다. α(j)는 기지국이 단말에게 알려주는 값이다.

,

,

,

,

The base station informs the terminal through a higher layer signal.

The base station dynamically informs the terminal through the TPC command of the PDCCH.

Is a terminal-specific parameter (eg, 4 bits) that is a power offset value for SRS transmission and is semi-statically configured in an upper layer and is a value signaled by the base station to the terminal.

Is a value indicating a current PUSCH power control adjustment state and may be expressed as a current absolute value or an accumulated value. α (j) is a cell-specific parameter that the base station transmits in 3 bits, for example, when j = 0 or 1, and α∈ {0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1} And when j = 2, α (j) = 1. α (j) is a value that the base station informs the terminal.

P _CMAX denotes a transmission power of a configured UE, M _SRS denotes a bandwidth of SRS transmission in subframe i expressed by the number of resource blocks, and P _{O _ PUSCH} (j) denotes a cell-specific nominal component ( nominal component) A parameter composed of a sum of P _{O _ NOMINAL _ PUSCH} (j) and a UE-specific component P _{O _ UE _ PUSCH} (j) provided from an upper layer.

PL is a downlink path loss (or signal loss) estimate calculated by the terminal in dB and is represented by PL = referenceSignalPower-higher layer filteredRSRP.

Equations for controlling the transmission power of the periodic SRS and the non-periodic SRS may be defined by redefining the configuration parameters of Equation 16 or adding a new parameter.

The power control equation for the SRS transmission proposed in the present invention can be expressed as Equation 17 below.

,

,

,

, PL,

에 대한 값들은 공통으로 하며, V값만이 다르게 적용된다.Here, V denotes a power offset applied only during aperiodic SRS transmission, and the base station may signal the terminal with one or more values through an upper layer signal. When V is set to one value, the same aperiodic SRS power offset may always be applied regardless of the type of the DCI format (0/3 / 3A) and the Accumulation - enabled value, which is a UE-specific parameter. On the other hand, when V is set to one or more values, aperiodic power offset may be applied differently according to a combination of DCI format (0/3 / 3A) and Accumulation - enabled value. As an example, the power offset applied after the TPC command of the PDCCH may be set differently according to the type of SRS transmitted by the UE in subframe i. At this time, the periodic and non-periodic SRS

,

,

,

, PL,

The values for are common and only the V values apply differently.

를 아래의 수학식 18과 같이 재정의할 수 있다. 이와 같은 동작 방식의 경우,

,

,

,

, PL 값들이 주기적 SRS와 비주기적 SRS 사이에서 공유되며,

값만이 다르게 적용된다.Another power control equation for SRS transmission proposed in the present invention may be expressed as Equation 18 below. This power control equation allows the transmission power offsets of periodic and aperiodic SRSs to be calculated and operated completely independently. That is, the equation (17)

Can be redefined as in Equation 18 below. For this type of operation,

,

,

,

, PL values are shared between periodic and aperiodic SRS,

Only values are applied differently.

는 기존의

와 동일한 계산 방식을 따르지만, DCI 포맷(0/3/3A)과 Accumulation - enabled 값의 조합에 따라 선택되는 δ _PUSCH값을 다르게 설정할 수 있다. 또한,

를

와 완전히 다른 계산 방식과 δ _PUSCH값으로 정의할 수 도 있다. here,

Existing

According to the same calculation method as, but the δ _PUSCH value selected according to the combination of DCI format (0/3 / 3A) and Accumulation - enabled value can be set differently. Also,

To

It can also be defined as a completely different calculation method and δ _PUSCH value.

값이 주기적 SRS 전송을 위한 전력 제어식과 비주기적 SRS 전송을 위한 전력 제어식에서 공통되지 않고 독립적이다. 이와 같이,

를 주기적 SRS 전송과 비주기적 SRS 전송에 대해 독립적으로 적용하는 실시 예로서, 비주기적 SRS 트리거링을 위해 전송되는 DCI 포맷의 TPC 정보를 이용하는 방식을 제안한다. 기지국이 비주기적 SRS 트리거링을 위해 사용되는 DCI 포맷은 비주기적 SRS 트리거링 비트를 포함한 기존의 DCI 포맷을 이용하거나 비주기적 SRS 트리거링 만을 위해 새롭게 정의된 DCI 포맷을 사용할 수도 있다. 또한, 비주기적 SRS 트리거링을 위한 DCI 포맷은 항상 2 비트의 TPC 정보를 가지고 있다고 가정한다. 상기 제안된 방식은 이러한 조건하에서, 기지국이 2 비트의 TPC 정보를 통해서 단말에게 전력 옵셋 값을 직접적으로 동적으로 알려주는 것이다. 전력 옵셋은 절대값(absolute) 또는 누적된 값(accumulated)일 수 있으며, 이 전력 옵셋은 비주기적 SRS의 전송 전력 제어에만 영향을 미친다. Additionally, as shown in Equation 18, in the power control equation

The values are not common and independent in power control for periodic SRS transmission and power control for aperiodic SRS transmission. like this,

As an embodiment of independently applying to periodic SRS transmission and aperiodic SRS transmission, a method of using TPC information of DCI format transmitted for aperiodic SRS triggering is proposed. The DCI format used by the base station for aperiodic SRS triggering may use an existing DCI format including an aperiodic SRS triggering bit or a newly defined DCI format only for aperiodic SRS triggering. In addition, it is assumed that the DCI format for aperiodic SRS triggering always has 2 bits of TPC information. According to the proposed scheme, under this condition, the base station directly and dynamically informs the terminal of the power offset value through 2 bits of TPC information. The power offset may be absolute or accumulated, which only affects transmit power control of aperiodic SRS.

Another power control equation for the SRS transmission proposed in the present invention can be expressed as Equation 19 below.

값을 하나가 아닌 2개로 시그널링하여 SRS의 종류에 따라 서로 다른 전력 옵셋이 적용되도록 한다. 기지국은 주기적 SRS 전송과 비주기적 SRS 전송을 구분하여 별도로

값을 단말에게 시그널링해 줄 수 있다. 예를 들어, 트리거 타입 0 (trigger type 0)으로 기지국은 주기적 SRS 전송을 위한 전력 옵셋값을 상위 계층 시그널링으로 단말에게 알려줄 수 있다. 또한, 트리거 타입 1(trigger type 1)으로 기지국은 비주기적 SRS 전송을 위한 전력 옵셋값을 상위 계층 시그널링으로 단말에게 알려줄 수 있다. 여기서, 기지국은 비주기적 SRS 전송을 위한 전력 옵셋값을 FDD 및 TDD 시스템에서는 DCI 포맷 0/4/1A를 통해 단말에게 전송해 줄 수 있고, 또는 TDD 시스템에서 대해서는 DCI 포맷 2B/2C 포맷을 통해 단말에게 전송해 줄 수 있다. 트리거 타입 0과 트리거 타입 1이 동일 서브프레임에서 트리거링(혹은 발생)되는 경우에는, 단말은 트리거 타입 1 SRS 전송(즉, 비주기적 SRS 전송)만을 수행할 수 있다.In this scheme, the base station is UE-specific through higher layer signals.

Signaling the value as two instead of one allows different power offsets to be applied according to the type of SRS. The base station distinguishes periodic SRS transmission and aperiodic SRS transmission separately.

The value can be signaled to the terminal. For example, as a trigger type 0, the base station may inform the terminal of a power offset value for periodic SRS transmission through higher layer signaling. In addition, as a trigger type 1, the BS may inform the UE of a power offset value for aperiodic SRS transmission through higher layer signaling. Here, the base station may transmit a power offset value for aperiodic SRS transmission to the terminal through DCI format 0/4 / 1A in the FDD and TDD systems, or via the DCI format 2B / 2C format in the TDD system. Can be sent to When trigger type 0 and trigger type 1 are triggered (or generated) in the same subframe, the terminal may perform only trigger type 1 SRS transmission (ie, aperiodic SRS transmission).

을 제외한 모든 파라미터들은 주기적 SRS를 전송하기 위한 전력 제어 식과 비주기적 SRS를 전송하기 위한 전력 제어 식에서 공통된다. 또한,

대신

를 이용하여 동일한 동작을 수행할 수도 있다. 따라서, 단말의 프로세서(255)는 기지국으로부터 상위 계층 시그널링 등을 통해 수신한 주기적 SRS 전송을 위한 전력 옵셋값과 비주기적 SRS 전송을 위한 전력 옵셋값에 기초하여, 해당 모드에 따라 SRS 옵셋값을 적용하여 주기적 SRS 전송을 위한 상향링크 전송 전력값, 비주기적 SRS 전송 전력값을 계산할 수 있다. in this case,

All parameters except for are common to a power control equation for transmitting a periodic SRS and a power control equation for transmitting an aperiodic SRS. Also,

instead

The same operation may be performed using. Accordingly, the processor 255 of the terminal applies the SRS offset value according to the corresponding mode based on the power offset value for periodic SRS transmission and the power offset value for aperiodic SRS transmission received from the base station through higher layer signaling. The uplink transmission power value and the aperiodic SRS transmission power value for periodic SRS transmission can be calculated.

Another power control equation for SRS transmission proposed by the present invention can be expressed as Equation 20 below.

This method is a hybrid method, which is a combination of the first method described in Equation 17 and the third method described in Equation 19, and the UE provides power for periodic SRS transmission and power for aperiodic SRS transmission. Can be set differently. For example, after setting the power offset for the aperiodic SRS transmission power using Equation 19, the power offset of Equation 17 may be additionally applied to widen the range of offset value selection. In another embodiment, the transmit power offset of the aperiodic SRS set through Equation 19 is configured to be an inaccurate value, and the power offset applied through Equation 17 is a relatively fine value. Setting this to allow more detailed power control than conventional methods. The same effects and results can also be obtained by a combination of the method using Equation 18 and the method using Equation 19.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above detailed description should not be interpreted as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Claims (20)

A method for transmitting an SRS based on aperiodic sounding reference signal (SRS) triggering in a wireless communication system,
Receiving a plurality of aperiodic SRS configuration information from a base station;
Receiving an indicator for triggering aperiodic SRS transmission from the base station;
Based on at least one of a subframe index for receiving the aperiodic SRS transmission triggering indicator, a time relationship between a receiving subframe of the aperiodic SRS transmission triggering indicator, and a non-periodic SRS transmission subframe corresponding to the aperiodic SRS transmission triggering indicator, and an uplink channel state Selecting specific aperiodic SRS configuration information among the aperiodic SRS configuration information of the; And
Transmitting the aperiodic SRS for the aperiodic SRS transmission triggering indicator based on the selected aperiodic SRS configuration information,
Wherein the plurality of aperiodic SRS configuration information includes information on resources for transmitting aperiodic SRS in response to the aperiodic SRS transmission triggering indicator. The method of claim 1,
The aperiodic SRS transmission is a first aperiodic SRS transmission, which is the fastest subframe among the preconfigured periodic SRS transmission subframes subsequent to the subframe n, if the subframe receiving the aperiodic SRS transmission triggering indicator is a subframe n. If the subframe or the subframe receiving the aperiodic SRS transmission triggering indicator is subframe n, the second aperiodic SRS transmission sub which is the fastest subframe among the preconfigured periodic SRS transmission subframes after subframe n + 3. Aperiodic SRS Triggering-based SRS Transmission Method Through Frames The method of claim 2,
If the subframe index n receiving the aperiodic SRS transmission triggering indicator is even,
Aperiodic SRS for transmitting the aperiodic SRS on a partial-band on a frequency axis of the first aperiodic SRS subframe or the second aperiodic SRS subframe in the step of transmitting the aperiodic SRS Triggering based SRS transmission method. The method of claim 2,
If the subframe index n receiving the aperiodic SRS transmission triggering indicator is odd, the entire band on the frequency axis of the first aperiodic SRS subframe or the second aperiodic SRS subframe in the step of transmitting the aperiodic SRS. Aperiodic SRS triggering based SRS transmission method for transmitting the aperiodic SRS over a full-band. The method of claim 2,
If the time relationship between subframe n, which is a subframe receiving the aperiodic SRS transmission triggering indicator, and one or more periodic SRS transmission subframes allocated to the UE, is a time difference corresponding to four subframes, the plurality of aperiodic SRSs Select a first aperiodic SRS configuration among the configurations, and according to the first aperiodic SRS configuration
And transmitting the aperiodic SRS through the first aperiodic SRS subframe. 6. The method of claim 5,
Wherein the aperiodic SRS transmits on the full-band on the frequency axis of the first aperiodic SRS subframe. The method of claim 2,
If the time relationship between subframe n, which is a subframe receiving the aperiodic SRS transmission triggering indicator, and one or more periodic SRS transmission subframes allocated to the UE, is not a time difference corresponding to four subframes, the plurality of aperiodic periods And selecting a second aperiodic SRS configuration among the SRS configurations, and transmitting the aperiodic SRS through the second aperiodic SRS subframe according to the second aperiodic SRS configuration. The method of claim 7, wherein
Wherein the aperiodic SRS transmits on a partial-band on the frequency axis of the second aperiodic SRS subframe. The method of claim 2,
If the uplink channel state is not better than a predefined channel state, a second aperiodic SRS configuration is selected from the plurality of aperiodic SRS configurations, and the first aperiodic SRS configuration is determined according to the second aperiodic SRS configuration. And transmitting the aperiodic SRS over a partial-band on the frequency axis of the subframe or the second aperiodic SRS subframe. The method of claim 2,
When the uplink channel state is better than a predefined channel state degree, a first aperiodic SRS configuration is selected from among the plurality of aperiodic SRS configurations, and the first aperiodic SRS substructure is configured according to the first aperiodic SRS configuration. And transmitting the aperiodic SRS over a full-band on a frame or frequency axis of the second aperiodic SRS subframe. The method of claim 3, wherein
If the transmit power is not sufficient to transmit the aperiodic SRS corresponding to the aperiodic SRS transmission triggering indicator, the aperiodic SRS is transmitted through a predefined fallback aperiodic SRS resource in the sub-band. ARS transmission method based on aperiodic SRS triggering. The method of claim 4, wherein
If the transmit power is not sufficient to transmit the aperiodic SRS corresponding to the aperiodic SRS transmission triggering indicator, the aperiodic SRS is transmitted through a predefined fallback aperiodic SRS resource in the full-band. ARS transmission method based on aperiodic SRS triggering. A method for controlling uplink transmission power for aperiodic sounding reference signal (SRS) transmission in a wireless communication system, the terminal comprising:
Receiving a power offset value for aperiodic SRS transmission from a base station;
Determining the aperiodic SRS transmission power value using the power offset value for the aperiodic SRS transmission; And
And transmitting the aperiodic SRS with the determined aperiodic SRS transmission power value. The method of claim 13,
The power offset value for only aperiodic SRS transmission is a value received through higher layer signaling, which is a specific value for each terminal, uplink transmission power control method for aperiodic SRS transmission. The method of claim 13,
Receiving an indicator for triggering the aperiodic SRS transmission from the base station,
The aperiod SRS transmission is performed according to the aperiodic SRS transmission triggering indicator, uplink transmission power control method for aperiodic SRS transmission. A method for controlling uplink transmission power for aperiodic sounding reference signal (SRS) transmission in a wireless communication system, the terminal comprising:
Receiving a power offset value for periodic SRS transmission and a power offset value for aperiodic SRS transmission from a base station;
Receiving an indicator from the base station to trigger aperiodic SRS transmission; And
Determining a transmission power value for the aperiodic SRS transmission using the power offset value for the aperiodic SRS transmission according to the aperiodic SRS transmission triggering indicator. Control method. 17. The method of claim 16,
And transmitting the aperiodic SRS with the determined aperiodic SRS transmission power value. 17. The method of claim 16,
The determination of the aperiodic SRS transmission power value is determined in units of a subframe, uplink transmission power control method for aperiodic SRS transmission. A terminal apparatus for transmitting an SRS based on an aperiodic sounding reference signal (SRS) triggering in a wireless communication system,
A receiver for receiving a plurality of aperiodic SRS configuration information from a base station and an indicator for triggering aperiodic SRS transmission from the base station;
Based on at least one of a subframe index for receiving the aperiodic SRS transmission triggering indicator, a time relationship between a receiving subframe of the aperiodic SRS transmission triggering indicator, and a non-periodic SRS transmission subframe corresponding to the aperiodic SRS transmission triggering indicator, and an uplink channel state A processor for selecting specific aperiodic SRS configuration information among the aperiodic SRS configuration information of the processor; And
And a transmitter for transmitting an aperiodic SRS for the aperiodic SRS transmission triggering indicator based on the selected aperiodic SRS configuration information.
The plurality of aperiodic SRS configuration information includes information on resources for transmitting aperiodic SRS in response to the aperiodic SRS transmission triggering indicator. A terminal apparatus for controlling uplink transmission power for aperiodic sounding reference signal (SRS) transmission in a wireless communication system,
A receiver for receiving a power offset value for periodic SRS transmission, a power offset value for aperiodic SRS transmission, and an indicator for triggering aperiodic SRS transmission from a base station; And
And a processor for determining a transmission power value for the aperiodic SRS transmission using the power offset value for the aperiodic SRS transmission according to the aperiodic SRS transmission triggering indicator.

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