KR20180011022A - Method and apparatus for configuration of multiple demodulation reference siganl structures in wireless cellular communication system - Google Patents

Abstract

The present disclosure relates to a communication technique that fuses a 5G communication system with IoT technology to support a higher data rate than a 4G system, and a system thereof. The present disclosure can be used for an intelligent service (for example, smart home, smart building, smart city, smart car or connected car, health care, digital education, retail, security and safety related service, etc.) based on 5G communication technology and IoT related technology. The present invention discloses a method of configuring a plurality of demodulation reference signal (DMRS) structures and determining uplink and downlink transmission timings for delay reduction. A method for processing a control signal includes a step of determining a control signal; a step of transmitting the control signal to a terminal; and a step of transmitting a DMRS to the terminal.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for setting a plurality of DMRS structures in a wireless cellular communication system,

The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for setting up a plurality of demodulation reference signal (DMRS) structures and determining uplink and downlink transmission timings for delay reduction.

Efforts are underway to develop an improved 5G or pre-5G communication system to meet the growing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G network) communication system or after a LTE system (Post LTE). To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In order to mitigate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave, in the 5G communication system, beamforming, massive MIMO, full-dimension MIMO (FD-MIMO ), Array antennas, analog beam-forming, and large scale antenna technologies are being discussed. In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Have been developed. In addition, in the 5G system, the Advanced Coding Modulation (ACM) scheme, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), the advanced connection technology, Filter Bank Multi Carrier (FBMC) (non-orthogonal multiple access), and SCMA (sparse code multiple access).

On the other hand, the Internet is evolving into an Internet of Things (IoT) network in which information is exchanged between distributed components such as objects in a human-centered connection network where humans generate and consume information. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired / wireless communication, network infrastructure, service interface technology and security technology are required. In recent years, sensor network, machine to machine , M2M), and MTC (Machine Type Communication). In the IoT environment, an intelligent IT (Internet Technology) service can be provided that collects and analyzes data generated from connected objects to create new value in human life. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, and advanced medical service through fusion of existing information technology . ≪ / RTI >

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as a sensor network, a machine to machine (M2M), and a machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antennas It is. The application of the cloud RAN as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

Also, unlike the LTE system, 5G wireless communication considers a system operating in a higher frequency band than the 6GHz frequency band. Since the channel characteristics depend on the frequency band, it is necessary to newly design the reference signal in consideration of this in the 5G system. In addition, low latency and high mobility are considered important in 5G wireless communication, and it is important to minimize the overhead of the reference signal.

It is an object of the present invention to provide a method of configuring and setting a plurality of demodulation reference signal (DMRS) structures in a 5G system operating in a higher frequency band than a frequency band of 6 GHz or lower, While minimizing the overhead of the reference signal.

Another object of the present invention is to minimize overhead of a reference signal by providing a method of constructing and feedbacking information necessary for a terminal to select a DMRS suitable for a transmission environment among the configurations of a plurality of DMRSs.

Another object of the present invention is to provide a method of determining a transmission timing such as a HARQ ACK / NACK transmission timing or a PUSCH transmission timing when a time required for signal processing of a Node B and a UE is reduced in an LTE system using FDD or TDD Thereby reducing the delay time for data transmission.

According to an aspect of the present invention, there is provided a base station (BS) method comprising: determining control information including at least one of symbol position information and symbol number information on a time axis on which a demodulation reference signal (DMRS) , Transmitting the control information to the terminal, and transmitting the DMRS corresponding to the determined control information to the terminal.

The base station according to an embodiment of the present invention includes a control unit for determining control information including at least one of symbol position information and symbol number information on a time axis on which a transmission and reception unit and a demodulation reference signal (DMRS) are transmitted, May transmit the control information to the terminal and control the transceiver to transmit the DMRS corresponding to the determined control information to the terminal.

A terminal method according to an embodiment of the present invention includes receiving control information including at least one of symbol position information and symbol number information on a time axis on which a demodulation reference signal (DMRS) is transmitted from a base station, And receiving the corresponding DMRS.

A terminal according to an embodiment of the present invention includes a transmitter and receiver for receiving control information including at least one of symbol position information and symbol number information on a time axis on which a demodulation reference signal (DMRS) is transmitted from a base station, And a controller for controlling the transceiver to receive the corresponding DMRS.

In another embodiment of the present invention, a method of a terminal includes receiving a first signal in an nk-th subframe from a base station, subframes to transmit a second signal corresponding to the first signal, 3-7a] and transmitting the second signal in the identified subframe.

[Table 3-7a]

In addition, in yet another embodiment of the present invention, the step of confirming the subframe for transmitting the second signal in the [Table 3-7a] may further comprise: receiving timing of the first signal in the [Table 3-7a] And determining transmission timing of the second signal corresponding to the received timing of the first signal.

Also, in another embodiment of the present invention, the first signal includes a physical downlink shared channel (PDSCH), and the second signal may include ACK / NACK information for the PDSCH.

According to another aspect of the present invention, there is provided a base station method comprising: transmitting a first signal in an nk-th subframe to a mobile station; and transmitting a subframe for receiving a second signal corresponding to the first signal, Confirming in [Table 3-7a], and receiving the second signal in the identified subframe.

[Table 3-7a]

In addition, in another embodiment of the present invention, the step of confirming the subframe for receiving the second signal in the [Table 3-7a] includes the steps of transmitting the first signal in the [Table 3-7a] And determining a reception timing of the second signal corresponding to the determined transmission timing of the first signal.

According to an embodiment of the present invention, a method of configuring a plurality of demodulation reference signals (DMRS) and setting a DMRS structure suitable for a transmission environment is provided. This makes it possible to effectively perform channel estimation according to low latency support and high mobility support environments in a channel environment of a 5G wireless communication system. Also, the transmission of the DMRS is environmentally adaptive, minimizing the overhead of the reference signal and enabling efficient transmission of radio resources.

According to another embodiment of the present invention, a base station provides a method of configuring and feedbacking necessary information in order to select a DMRS suitable for a transmission environment among a plurality of configurations of a demodulation reference signal (DMRS). It is possible to environmentally adaptively transmit the DMRS through the present invention to minimize the overhead of the reference signal.

In addition, according to another embodiment of the present invention, a method for determining a HARQ ACK / NACK transmission timing or a data transmission timing is provided to reduce a delay time.

1A is a diagram illustrating a downlink time-frequency domain transmission structure of an LTE or LTE-A system.
1B is a diagram illustrating an uplink time-frequency domain transmission structure of an LTE or LTE-A system.
1C is a diagram illustrating a radio resource of 1 RB which is a minimum unit that can be downlink-scheduled in an LTE or LTE-A system.
FIG. 1D, FIG. 1E, FIG. 1Fa, FIG. 1Fab, FIG. 1Fba, FIG. 1Fbb and FIG. 1g are views showing the structure of a plurality of DMRSs according to the first embodiment of the present invention.
1 HA and 1 HB are views illustrating an example of a method of supporting MU transmission orthogonally between terminals using different DMRS structures according to the first through third embodiments of the present invention.
1I is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention.
1J is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention.
1K is a diagram showing a position of the front-load DMRS in a case where the slot length is 7 or 14 OFDM symbols.
1L, 11B, 11C, 11D, 11E, and 11F illustrate a position where an extended / additional DMRS is transmitted, where a slot has a length of 7 or 14 OFDM symbols.
1M is a view for explaining a DMRS structure according to an embodiment of the present invention.
FIG. 1n is a view for explaining a method of mapping an antenna port to the unit DMRS structure proposed in FIG. 1m.
FIG. 10 is a diagram illustrating a method of mapping a larger number of antenna ports to the unit DMRS structure proposed in FIG.
2A, 2B, and 2C are diagrams illustrating a radio resource configuration of an LTE system.
FIG. 2D is an exemplary diagram showing feedback timing of information necessary for selection of a reference signal according to the embodiment 2-2 of the present invention. FIG.
FIG. 2E is a diagram illustrating a method of separating a reference signal based on feedback of information necessary for selecting a reference signal according to the second and third embodiments of the present invention. FIG.
2F is a block diagram illustrating an internal structure of a UE according to embodiments of the present invention.
2G is a block diagram illustrating an internal structure of a base station according to embodiments of the present invention.
3A is a diagram illustrating a downlink time-frequency domain transmission structure of an LTE or LTE-A system.
3B is a diagram illustrating an uplink time-frequency domain transmission structure of an LTE or LTE-A system.
3C is a diagram showing data allocated for eMBB, URLLC, and mMTC in frequency-time resources in the communication system.
FIG. 3D is a diagram showing data allocated for eMBB, URLLC, and mMTC in frequency-time resources in a communication system.
3E is a diagram illustrating a structure in which one transport block according to the embodiment is divided into several code blocks and CRC is added.
FIG. 3F is a diagram illustrating a structure in which an outer code according to the embodiment is applied and coded.
FIG. 3G is a block diagram of the outer code according to the embodiment of the present invention.
3H is a diagram illustrating a terminal operation according to Embodiments 3-1, 3-2, 3-3, and 3-4.
FIG. 3I is a diagram illustrating a terminal operation according to the 3-5th embodiment, the 3-6th embodiment, the 3-7th embodiment, and the 3-8th embodiment.
3J is a block diagram showing the structure of a terminal according to the embodiments.
3K is a block diagram illustrating the structure of a base station according to embodiments.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

For example, 3GPP's High Speed Packet Access (HSPA), LTE (Long Term Evolution or Evolved Universal Terrestrial Radio Access (E-UTRA)), LTE-Advanced To a broadband wireless communication system that provides high-speed, high-quality packet data services such as the LTE-A, 3GPP2 high rate packet data (HRPD), UMB (Ultra Mobile Broadband), and IEEE 802.16e communication standards. . In addition, a 5G or NR (new radio) communication standard is being produced with the fifth generation wireless communication system.

≪ Embodiment 1 >

In a wireless communication system, a base station must transmit a reference signal for estimating a channel. The UE can perform channel estimation using the reference signal and demodulate the received signal. Also, the UE can use the reference signal to grasp the channel state and feed back the channel state to the base station.

Generally, when a reference signal is transmitted, the transmission interval of the reference signal based on the frequency and the time is determined in consideration of the maximum delay spread and the maximum Doppler spread of the channel. As the transmission interval of the reference signal becomes narrower, the channel estimation performance improves and the demodulation performance of the signal can be improved. However, this results in increasing the overhead of the reference signal and limiting the data transmission rate.

Conventionally, a 4G LTE system operating in a frequency band of 2 GHz uses reference signals such as a CRS (cell-specific reference signal) and a DMRS (demodulation reference signal) in the downlink. If the interval of the reference signal in the frequency domain is represented by a subcarrier interval m of an orthogonal frequency division multiplexing (OFDM) signal and the interval of the reference signal is represented by a symbol interval n of the OFDM signal in time, a normal cyclic prefix (m, n) = (3, 4), the transmission interval based on the frequency and time of the reference signal corresponding to antenna ports 1 and 2 is CRS. In case of DMRS assuming normal CP, the transmission interval based on the frequency and time of the reference signal is (m, n) = (5, 7).

Unlike the LTE system, the 5G wireless communication system considers a system operating in a higher frequency band than the 6GHz frequency band. Since the channel characteristics depend on the frequency band, it is necessary to newly design the reference signal in consideration of this in the 5G system.

In the LTE / LTE-A system, a typical example of the broadband wireless communication system is an Orthogonal Frequency Division Multiplexing (OFDM) scheme in a downlink (DL) Carrier Frequency Division Multiple Access (CDMA) scheme. The uplink refers to a radio link through which a UE (User Equipment) or an MS (Mobile Station) transmits data or a control signal to a base station (eNode B or base station (BS) The term " wireless link " In the above multiple access scheme, time-frequency resources are allocated and operated so that time-frequency resources to transmit data or control information for each user do not overlap with each other, that is, orthogonality is established, Control information is distinguished.

1A is a diagram illustrating a basic structure of a time-frequency domain, which is a radio resource region in which the data or control channel is transmitted in the downlink in an LTE / LTE-A system.

In Fig. 1A, the abscissa represents the time domain and the ordinate axis represents the frequency domain. The minimum transmission unit in the time domain is an OFDM symbol, and N _symb (102) OFDM symbols constitute one slot 106, and two slots form one subframe 105. The length of the slot is 0.5 ms and the length of the subframe is 1.0 ms.

The radio frame 114 is a time domain including 10 subframes. The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the total system transmission bandwidth is composed of a total of N _BW (104) subcarriers.

In a time-frequency domain, a basic unit of a resource can be represented by an OFDM symbol index and a subcarrier index as a resource element (RE) 112. A resource block (RB or Physical Resource Block) 108 is defined as N _symb (102) consecutive OFDM symbols in the time domain and N _RB (110) consecutive subcarriers in the frequency domain. Thus, one RB 108 is comprised of N _symb x N _RB REs 112.

In general, the minimum transmission unit of data is the RB unit. In the LTE system, N _symb = 7, N _RB = 12, and N _BW and N _RB are generally proportional to the bandwidth of the system transmission band. The data rate increases in proportion to the number of RBs scheduled to the UE. The LTE system defines and operates six transmission bandwidths. In the case of an FDD system in which the downlink and the uplink are classified by frequency, the downlink transmission bandwidth and the uplink transmission bandwidth may be different from each other. The channel bandwidth represents the RF bandwidth corresponding to the system transmission bandwidth.

 [Table 1-1] shows the correspondence relationship between the system transmission bandwidth and the channel bandwidth defined in the LTE system. For example, an LTE system with a 10 MHz channel bandwidth has a transmission bandwidth of 50 RBs.

[Table 1-1]

1B is a diagram illustrating a basic structure of a time-frequency domain, which is a radio resource region in which data or a control channel is transmitted in an uplink in an LTE / LTE-A system.

Referring to FIG. 1B, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an SC-FDMA symbol 202, and N _symb ^UL SC-FDMA symbols form one slot 206. Then, two slots form one subframe 205. The minimum transmission unit in the frequency domain is a subcarrier, and the total system transmission bandwidth 204 is composed of a total of N _BW subcarriers. N _BW has a value proportional to the system transmission band.

The basic unit of resources in the time-frequency domain is a resource element (RE) 212, which can be defined as an SC-FDMA symbol index and a subcarrier index. A resource block pair (RB pair) 208 is defined as N _symb ^UL consecutive SC-FDMA symbols in the time domain and N _sc ^RB consecutive subcarriers in the frequency domain. Therefore, one RB consists of N _symb ^UL x N _sc ^RB REs. In general, the minimum transmission unit of data or control information is RB unit. In case of PUCCH, it is mapped to a frequency region corresponding to 1 RB and transmitted for 1 sub-frame.

1C shows a radio resource of 1 RB which is a minimum unit that can be downlink-scheduled in the LTE / LTE-A system. A plurality of different types of signals may be transmitted through the radio resources shown in FIG.

1. CRS (Cell Specific RS): A reference signal transmitted periodically for all UEs belonging to one cell and can be commonly used by a plurality of UEs.

2. Demodulation Reference Signal (DMRS): This is a reference signal transmitted for a specific terminal and is transmitted only when data is transmitted to the terminal. The DMRS can be composed of a total of 8 DMRS ports. In LTE / LTE-A, ports 7 to 14 correspond to DMRS ports, and ports maintain orthogonality so that they do not interfere with each other using CDM (Code Division Multiplexing) or FDM (Frequency Division Multiplexing).

3. Physical Downlink Shared Channel (PDSCH): A data channel transmitted in the downlink, which is used for the BS to transmit traffic to the UE, and is transmitted using the RE in which the reference signal is not transmitted in the data region of FIG.

4. Channel Status Information Reference Signal (CSI-RS): A reference signal transmitted for UEs belonging to one cell. A plurality of CSI-RSs can be transmitted to one cell.

5. Other control channels (PHICH, PCFICH, PDCCH): The terminal transmits ACK / NACK for providing control information necessary to receive PDSCH or Hybrid Automatic Repeat reQuest (HARQ) for uplink data transmission.

In this signal, CRS and DMRS are reference signals used for demodulating a signal received through channel estimation. Since the channel estimation performance directly affects the demodulation performance, the transmission interval based on the frequency and time of the reference signal is determined And maintaining. For example, if the interval of the reference signal on the frequency is expressed by the subcarrier interval m of the OFDM signal and the interval of the reference signal is represented by the symbol interval n of the OFDM signal in time, The transmission interval based on the frequency and time of the reference signal corresponding to 2 is (m, n) = (3, 4). Also, in case of DMRS assuming normal CP, the transmission interval based on the frequency and time of the reference signal is (m, n) = (5, 7).

Unlike the LTE system, the 5G wireless communication system considers a system operating in a higher frequency band than the 6GHz frequency band. Since the channel characteristics depend on the frequency band, it is necessary to design the reference signal in consideration of this in the 5G system. Also, in 5G wireless communication, it is important to support low latency of wireless signal transmission and support high mobility of wireless signals. In addition, it is important to minimize the overhead of the reference signal in 5G systems. Accordingly, the present invention provides a method of constructing a plurality of demodulation reference signal (DMRS) structures and a method of setting the DMRS to solve such a problem.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Embodiments of the present invention will be described below as an example of an LTE or LTE-A system, but the embodiments of the present invention can be applied to other communication systems having a similar technical background or channel form. For example, 5G mobile communication technology developed after LTE-A (5G, new radio, NR) could be included.

More specifically, the basic structure of the time-frequency domain in which signals are transmitted in downlink and uplink may differ from those shown in Figs. 1A and 1B. Also, the types of signals transmitted on the downlink and uplink may be different. Therefore, the embodiments of the present invention can be applied to other communication systems by a person skilled in the art without departing from the scope of the present invention.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification. Hereinafter, the base station may be at least one of an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing communication functions. In the present invention, a downlink (DL) is a wireless transmission path of a signal transmitted from a base station to a mobile station, and an uplink (UL) is a wireless transmission path of a signal transmitted from a mobile station to a base station.

The demodulation reference signal (DMRS) described below is transmitted by applying UE-specific precoding to the reference signal, so that the UE performs demodulation without further receiving precoding information It is assumed that the name used in the LTE system is used as it is. However, the term DMRS can be expressed in other terms depending on the intent of the user and the intended use of the reference signal. More specifically, the term DMRS is merely a specific example of the present invention in order to facilitate the understanding of the present invention, and is not intended to limit the scope of the present invention. That is, it is apparent to those skilled in the art that the present invention can be applied to a reference signal based on the technical idea of the present invention.

The structure of various DMRS according to the use case will be described in the embodiment 1-1 of the present invention to be described below. In Embodiment 1-2 of the present invention, a method of setting and transmitting a proper DMRS structure among a plurality of DMRS structures according to a transmission environment will be described. In Embodiments 1-3, a method of supporting Multiple-User (MU) transmission orthogonally between terminals using different DMRS structures when a plurality of DMRS structures are supported will be described.

[Example 1-1]

Embodiment 1-1 describes a method of configuring the structure of the DMRS, which is a reference signal of the present invention, according to a transmission environment.

Referring to FIG. 1C, the LTE system has one fixed DMRS structure. When the number of transmission layers is 2 or less, 12 DMRS REs are transmitted per RB. When the number of transmission layers exceeds 2, 24 DMRSs RE.

As described above, unlike the LTE system, the 5G wireless communication system considers not only a frequency band of 6 GHz or lower but also a system operating in a higher frequency band. Since the channel characteristics vary depending on the frequency band, the DMRS in the 5G system needs to be designed differently from the structure of the DMRS in LTE. In addition, low latency support and high mobility support are considered important for 5G systems. Therefore, a number of DMRS structures according to the transmission environment are required.

For example, in order to support low latency, the channel estimation must be performed quickly. For this purpose, the DMRS needs to be located on the transmission time axis. In order to support high mobility, , And for this purpose, the DMRS needs to be transmitted at a high density based on one transmission time base. Here, the density may mean the amount of resources (for example, the number of REs) to which the DMRS is transmitted in an arbitrary transmission unit.

Also, for example, in a 5G system, a reference signal such as CRS may not be supported. In general, CRS guarantees channel estimation performance even in a low signal-interference plus noise ratio (SINR) region (for example, -10 to 0 dB) due to high reference signal density. When CRS is not transmitted, It may be difficult to guarantee the channel estimation performance in the region.

Accordingly, the present invention proposes a method of configuring the structure of the DMRS variously according to the transmission environment.

In order to configure the structure of the DMRS variously, it is first necessary to set a position where the DMRS can be transmitted. The base station according to an exemplary embodiment of the present invention may determine and transmit a DMRS structure required at a set location when a DMRS location that can be transmitted is set. The terminal according to an embodiment of the present invention needs to know the transmission possible position of the DMRS.

Unlike the LTE system, the 5G wireless communication system can be configured in a variety of frame structures and can operate in a variable TTI (Transmission Time Interval), so the location setting for the DMRS needs to be specified separately as a terminal. Also, unlike in LTE, in the 5G wireless communication system, the number of OFDM symbols and the number of subcarriers on the frequency may vary with the time of the subframe. In the present invention, the number of OFDM symbols constituting a subframe and the number of subcarriers on a frequency constituting a resource block are set to be equal to LTE in most of the drawings, but this can be set differently. For example, as shown in Figs. 1faa, 1fab, 1fba and 1fb, one resource block may have 12 subcarriers on the frequency or 16 subcarriers on the frequency.

More specifically, the setting of the position where the DMRS can be transmitted can be divided into the position in time and the position in frequency, and can be set as a combination of position in time and position in frequency.

First, there are two ways to consider the location of the time in which the DMRS can be transmitted. The first method is to set a position in time in which the DMRS is transmitted based on the subframe. This is generally a method considering location setting for a transmission resource in units of subframes.

For example, when the duration corresponding to one subframe is denoted by x, a method in which the position of the DMRS is set to a unit of y = x / 2 can be considered. 1Fa to 1FbA, if the DMRS is set to x = 14 (OFDM symbol), the position of the DMRS may be set to a unit of y = 7, and the temporal position of the settable DMRS in one subframe may be 3/6/9 / 12th OFDM symbol.

The second method is to set the position of the time when the DMRS is transmitted based on the starting point of the allocated data channel (ex. PDSCH). Unlike the LTE system, the 5G wireless communication system considers that the interval during which a data channel is transmitted in a subframe may be variously set. For example, based on the start point of the data channel, the time position of the settable DMRS may be 1/4/7/10 th OFDM symbol.

Next, the position on the frequency at which the DMRS can be transmitted can be set to have a density considering the channel environment of the 5G communication system covering various numerologies. Here, the numerology may mean subcarrier spacing (e.g., the frequency difference between subcarriers), and the length of the interval of the subcarriers on the frequency is the length of the symbol on the time axis . ≪ / RTI >

For example, a transmission position on the frequency of the DMRS may be set such that the DMRS is transmitted via at least two consecutive subcarriers. For example, as shown in FIGS. 1Fa-4-1 and 1Fa-4-2 in FIG. 1Fab, positions of two frequencies on which the DMRS can be transmitted are shown.

As described above, the setting of the position at which the DMRS can be transmitted can be set to a combination of the position in time and the position in frequency, and the DMRS setting actually used may be set to a subset of possible combinations for convenience . Also, the transmitted DMRS structure may be implicitly determined according to the position in time and the number of DMRS layers transmitted, in which the DMRS described above can be transmitted.

More specifically, the DMRS structure proposed in Figs. 1faa and 1fab will be described.

When the DMRS is set for only one OFDM symbol located on the time axis in one subframe in order to support low latency as shown in FIG. 1fa-2-1 and FIG. 1fa-2-2, layer can be distinguished according to the number of layers. For example, when the number of transmitted layers is 4 or less, a reference signal can be more densely allocated on the frequency as shown in FIG. 1fa-2-2. On the other hand, when the number of transmitted layers is larger than 4, a reference signal having a low density on the frequency can be allocated as shown in FIG. 1fa-2-1. However, the reference signal set to have a low density as shown in FIG. 1f-2-1 may be difficult to guarantee the channel estimation performance.

As another example, if the DMRS is set for two OFDM symbols in one subframe as shown in FIG. 1Fa-3-1 and FIG. 1Fa-3-2, if the number of transmitted layers is 4 or less, The reference signal can be allocated more dense on the frequency as shown in 3-2. Also, when the number of transmitted layers is larger than 4, a reference signal having a low density on the frequency can be allocated as shown in FIG. 1fa-3-1.

As another example, in order to supplement the environment where the degree of the Doppler effect is strong (hereinafter, it is used in combination with the term High Doppler) as shown in Fig. 1fa-4-1 and 1fa-4-2, When the number of transmitted layers is set to four or less on the time axis in the subframe, the reference signal can be allocated as shown in FIG. 1fa-4-2. In this case, if the reference signal is allocated more dense on the frequency, the overhead of the reference signal may become too large. If the number of transmitted layers is larger than 4, the reference signal can be allocated as shown in FIG. 1fa-4-1. However, in the high-speed transmission, the probability that the number of transmission layers is larger than 4 is very low.

If the number of transmitted layers is 4 or more, OCC (Orthogonal Cover Code) = 4 and OCC = 2 when the number of transmitted layers is 2 or less. The above example can be similarly applied to other DMRS structures. An example of the DMRS structure shown in Fig. 1Fba and Fig. 1Fbb can be similarly applied to a case where the number of subcarriers on the frequency side is 16 in one resource block.

Next, we propose a method of performing Doppler frequency measurement, phase noise compensation, and frequency offset correction using DMRS. In the conventional LTE system, it is possible to perform such an operation using the CRS. However, in the 5G communication system, when there is no signal to go out every subframe in the full band like CRS, the Doppler frequency measurement, the phase noise compensation, it may be difficult to perform operations such as offset correction.

In order to perform such an operation, a reference signal with a high temporal density is required. For example, when the DMRS is set only for one OFDM symbol in order to support low latency, it is impossible to perform the above operation using only the DMRS . Therefore, the base station can set the DMRS with high time density in the on-demand manner according to the request, and can perform operations such as Doppler frequency measurement, phase noise compensation, and frequency offset correction. More specifically, in order to perform such operations, the base station performs dynamic signaling and the terminal performs operations such as Doppler frequency measurement, phase noise compensation, and frequency offset correction using the set DMRS. For example, one bit can be added to DCI (dynamic control information) for signaling. Supporting a plurality of DMRS structures in the embodiment 1-1 is different from that of supporting a single fixed DMRS structure in the existing LTE system as follows. First, unlike existing LTE, the number of DMRS resource elements (REs) allocated per antenna port may not be fixed. For example, in an LTE system, the number of DMRS REs allocated per antenna port is fixed to 12. However, when a plurality of DMRS structures are supported, the number of DMRS REs allocated per antenna port is determined by which structure ≪ / RTI >

In addition, the number of supported antenna ports may vary depending on which structure is set among various DMRS structures. For example, in an environment where the overhead of the reference signal needs to be reduced, it is difficult to support a high rank. In this case, it is necessary to minimize the overhead of the reference signal by supporting only the minimum antenna port. Hereinafter, a concrete example of the above-mentioned differentiation can be confirmed through the various DMRS structures proposed.

For the reasons stated above, the first through eleventh embodiments of the present invention propose various DMRS structures according to transmission environments. Figure ID is a diagram illustrating a first example of various DMRS structures. 1D is a structure in which, for example, the DMRS can be transmitted on all subcarriers included in one OFDM symbol. However, the position of the DMRS proposed in the present invention is not limited to that shown in FIG. 1D.

More specifically, as shown in FIG. 1D-1, the DMRS can be located in each of the third OFDM symbol and the eleventh OFDM symbol. For example, as shown in FIG. 1D-1, the position of the DMRS can be transmitted through each of the third OFDM symbol and the twelfth OFDM symbol in one subframe for time balance. However, if the 5G system has a basic structure in a time-frequency domain different from that of the LTE / LTE-A system, the position of the DMRS may be changed.

As another example, in order to support low latency in the present invention, the position of the DMRS may be transmitted only through the third OFDM symbol in one subframe as shown in FIG. 1D-2. In this case, the UE can demodulate the received signal quickly because the channel can be estimated with the signal received up to the third OFDM symbol.

As another example, in order to support high mobility, the position of the DMRS can be transmitted through three different OFDM symbols in one subframe as shown in FIG. 1D-3.

The DMRS signal may be generated based on a pseudo-random sequence similar to the downlink DMRS in LTE, or may be generated based on a ZC (Zadoff-Chu) sequence similar to the uplink DMRS in LTE have. For example, when the uplink / downlink has the same DMRS structure, the DMRS signal generation can orthogonally support the uplink / downlink DMRS ports if the uplink and downlink are applied in the same manner.

Also, in FIG. 1D, it is possible to support a plurality of DMRS ports by applying OCC (Orthogonal cover code) on the frequency. When the OCC is applied to the frequency, there is an advantage that the power imbalance problem that may occur when OCC is applied in time does not occur. An example of this is shown in FIG.

FIG. 1E shows an example in which OCC is applied in a case where the number of subcarriers on a frequency is 16 in one resource block. In FIG. 1E, the DMRS port number is numbered from the 7th port to the 14th port based on the LTE system, which is an illustrative example. For example, the port number used in a 5G system may be different.

More specifically, FIG. 1E-1 shows an example of OCC applied when two ports (port 7, port 8) are used to transmit the DMRS. The OCC having the OCC length of 2 can be applied at the position where the port 7 and the port 8 are indicated as shown in FIG. 1E-1. Therefore, in FIG. 1E-1 and when the DMRS is transmitted using two ports, the DMRS may not be transmitted for all resources included in one OFDM symbol.

는 시퀀스 길이에 따른 시퀀스 값을 나타내며, OCC 크기가 2인 경우는

와

가 사용되며, OCC 크기가 4인 경우에는

가 모두 사용된다. 앞서 설명한 바와 같이 [표 1-2]도 LTE시스템을 기준으로 7번 포트부터 14번 포트로 넘버링을 하였지만, 이는 설명을 위한 예시이다. 예를 들어, 5G 시스템에서 사용되는 포트 넘버는 이와 다를 수 있다. The sequence for OCC is shown in [Table 1-2]. In Table 1-2,

Represents a sequence value according to the sequence length, and when the OCC size is 2

Wow

Is used, and when the OCC size is 4

Are all used. As described above, [Table 1-2] is numbered from port 7 to port 14 based on the LTE system, but this is an example for explanation. For example, the port number used in a 5G system may be different.

1E-2 shows an application example of OCC applied when four ports 7/8/9/10 are transmitted. An OCC having an OCC length of 2 can be applied at a position indicated by port 7/8/9/10 as shown in FIG. 1E-2. As shown in the figure, when four or more ports are transmitted, the DMRS can be transmitted for all the resources of the OFDM symbol. Next, FIG. 1e-3 shows an application example of OCC when 8 ports are transmitted. When more ports than four ports are used as in FIG. 1e-3, OCC length 4 is used.

Although FIG. 1E shows an example of OCC application for the case where 2/4/8 ports are transmitted, the application of 8 or fewer other ports can be easily extended from the example of FIG. 1E. For example, if only three ports are transmitted, only port 7/8/9 in FIG. 1e-1 is transmitted, so port 7/8 can be transmitted by applying OCC of length 2 at the corresponding position in FIG. 1e-1 However, the port 9 does not have the OCC of length 2 because there is no other port at the corresponding position of FIG. 1e-1.

[Table 1-2]

Next, Figs. 1faa, 1fab, 1fba and 1fbb show a second example of the proposed various DMRS structures. Figures 1faa, 1fab, 1fba, and 1fbb are modified constructions of the forms shown in Figures 1d and 1e above. Specifically, we propose a structure that can operate more effectively considering the overhead of the reference signal than the method shown in FIG. 1D and FIG. 1E through the DMRS position configuration and the antenna port mapping method on the proposed frequency.

The generation of the DMRS signal may be generated based on the pseudo-random sequence similar to the downlink DMRS in the LTE or may be generated based on the Zadoff-Chu (ZC) sequence similar to the uplink DMRS in the LTE. 1Fa and 1Fab show the structure when the number of subcarriers on the frequency constituting the resource block is 12. Fig. 1Fba and Fig. 1bbb show the structure when the number of subcarriers on the frequency constituting the resource block is 16. In Fig.

는 시퀀스 길이에 따른 시퀀스 값을 나타내며, OCC길이가 2인 경우는

와

가 사용되며, OCC 길이가 4인 경우에는

가 모두 사용된다. 도 1fa-1-2와 1fa-1-3에서 DMRS 포트 넘버를 LTE시스템을 기준으로 7번 포트부터 14번 포트로 넘버링을 하였지만, 이는 설명을 위한 예시이다. 예를 들어, 5G 시스템에서 사용되는 포트 넘버는 이와 다를 수 있다. First, Figs. 1Fa and 1Fab will be described. The method proposed in Figs. 1faa and 1fab can be used flexibly according to the transmission situation, as shown in Fig. 1fa-1-1. The OCC and antenna port mapping methods can be performed as shown in Figs. 1fa-1-2 and 1fa-1-3. In Table 1-2,

Indicates a sequence value according to the sequence length, and when the OCC length is 2

Wow

Is used, and when the OCC length is 4

Are all used. In FIGs. 1fa-1-2 and 1fa-1-3, the DMRS port numbers are numbered from the 7th port to the 14th port based on the LTE system, but this is an illustrative example. For example, the port number used in a 5G system may be different.

Referring to FIGS. 1Fa-1-2, a reference signal is not transmitted to a portion denoted by a lattice pattern but a reference signal may be transmitted only to a portion denoted by a hatched pattern. In this case, two ports 7/8 can be transmitted with OCC = 2 applied, and four ports 7/8/11/13 can be transmitted with OCC = 4 applied. On the other hand, when eight ports from port 7 to port 14 are transmitted, port 7/8/11/13 is transmitted with OCC = 4 applied in the hatched area, port 9 / 10/12/14 can be transmitted with OCC = 4 applied.

First, referring to FIG. 1fa-1-3, two ports 7/8 can be transmitted by applying OCC = 2 to the hatched portion, and four ports 7/8/11 / 13 may be transmitted with OCC = 4 applied. 1F-1-2 are methods for minimizing the overhead of the reference signal when the channel state is good, and FIGS. 1Fa-1-3 show the channel estimation performance by further using the reference signal when the channel state is not good . In FIGS. 1Fa-1-2 and 1Fa-1-3, a description has been given of a method in which the OCC is applied in the frequency domain, but the method in which the OCC is applied is not limited thereto.

As described above, the DMRS position shown in FIG. 1Fa-1-1 can be used flexibly according to the transmission situation in FIGS. 1Fa and 1Fab and FIGS. 1Fa-2-1 / 1fa-2-2 / 1fa-3-1 / 1fa-3-2 / 1fa-4-1 / 1fa-4-2 are examples of DMRS positions configurable according to transmission conditions. An embodiment of this will be described with reference to the above description.

As described above, Fig. 1Fba and Fig. 1Fbb show the structure in the case where the number of subcarriers on the frequency constituting the resource block is 16. The operation method for this is the same as in FIGS. 1Fa and 1Fab, and therefore, detailed description thereof will be omitted. The OCC and antenna port mapping method can be performed as shown in FIGS. 1Fb-1-2 and 1Fb-1-3, and the detailed operation is the same as in FIGS. 1Fa-1-2 and 1Fa-1-3. However, the method in which the OCC is applied in the present invention is not limited thereto.

The method proposed in FIG. 1fba and FIG. 1fbb can be flexibly used for the DMRS position shown in FIG. 1fb-1-1 depending on the transmission situation, and FIG. 1fb-2-1 / 1fb-3-1 / 1fb- 1fb-4-1 are examples of configurable DMRS locations.

Finally, FIG. 1g shows a third example of the various proposed DMRS structures. 1G is a structure in which the DMRS has a form similar to the current LTE system. Therefore, the OCC and antenna port mapping method applied in the DMRS of the LTE can be applied as it is. However, in the present invention, a DMRS structure different from the DMRS structure of the existing LTE system may be considered in order to satisfy the next generation communication requirement, depending on the channel environment. That is, the present invention proposes a method of constructing various DMRS structures by OFDM symbols according to the transmission environment by extending the DMRS structure of the existing LTE system.

FIG. 1G-1 shows the position of the DMRS that can be implemented in a general channel state. FIG. 1G-2 shows a structure in which additional DMRS is mapped on the time axis for high mobility support. FIGS. 1G-3-1 and 1G-3-2 show a method of lowering the DMRS density on the frequency axis in order to minimize the overhead of the reference signal in an environment with a small channel delay. Finally, to support low latency, a DMRS structure such as 1g-4-1 and 1g-4-2 can be used. As shown in FIG. 1G-4-1, when the position of the DMRS is transmitted only in the front OFDM symbol, only up to 4-layer transmission can be supported.

1D, 1Fa, 1Fab, 1Fba, 1Fbb and 1G, various DMRS structures according to transmission environments are shown. However, the DMRS structure in the present invention is not limited to the structure shown in the 1-1th embodiment. Therefore, the DMRS structure different from those of Figs. 1D, 1Fa, 1Fab, 1Fba, 1Fbb and 1g may be applied to the 1-2th embodiment and the 1-3th embodiment below.

Although the structure of the DMRS is described based on the downlink in the embodiment 1-1, the same DMRS structure may be set in the uplink in the 5G system. If the uplink / downlink has the same DMRS structure, the uplink / downlink DMRS ports can be operated more flexibly in an environment like TDD (Time Division Duplex) due to orthogonal canceling.

[Example 1-1-1 Example]

The 1-1-1 embodiment proposes another method of setting the structure of the DMRS proposed in the above 1-1 embodiment. In the 1-1-1 embodiment, it is noted that the configurable DMRS structure can be divided into a front-loaded DMRS and an extended / additional DMRS. First, the front-loaded DMRS can be defined by the following two criteria.

One. The number of OFDM symbols for front-loaded DMRS

● The front-loaded DMRS is mapped over 1 or 2 adjacent OFDM symbols

■ Front-loaded DMRS is mapped on 1 OFDM symbol for low rank transmission.

■ The front-loaded DMRS is mapped on 2 adjacent OFDM symbols for high rank transmission.

2. The location of time for front-loaded DMRS

● Opt. 1: The first symbol of the front-loaded DM-RS is fixed regardless of the first symbol of NR-PDSCH.

● Opt. 2: The first symbol of the front-loaded DM-RS is no later than the first symbol of the NR-PDSCH.

Specifically, the front-loaded DMRS may be configured into one or two adjacent OFDM symbols depending on the number of transmission layers. In addition, the front-loaded DMRS is located before the NR-PDSCH on the time axis, and its position can be fixed as described above, and the front-loaded RS can be located from the first symbol from which the NR-PDSCH starts.

The advantages and disadvantages of Opt. 1 and Opt. 2 will be described. In the case of Opt. 1, since the position of DMRS is fixed, it can be assumed that the DMRS of the next cell is always transmitted at the same position. However, in the case where the control channel region is set to be configurable, or in the case of a subframe in which the control channel is not transmitted, the DMRS of the data channel may not be positioned further before the decoding latency.

On the other hand, in the case of Opt.2, the advantage of the decoding latency problem is that the front-loaded DMRS is always located ahead of the data channel on the time axis. However, since the position of the front-loaded DMRS is varied, that is, the position of the DMRS is not fixed, thereby causing problems in inter-cell interference control and improved receiver operating. For this purpose, a method of introducing additional network signaling can be considered. However, in general, the method in which the DMRS position is fixed is advantageous for system operation.

Therefore, we propose a concrete method of setting the front-load DMRS to a fixed position for the above reasons. The position of the front-load DMRS is shown in FIG. 1k for the slot length of 7 or 14 OFDM symbols, respectively. Here, the position of the front-load DMRS can be determined by the area of the control channel. For example, when the control channel region is composed of a maximum of two OFDM symbols, the front-load DMRS is located in the third OFDM symbol as k-1. As another example, when the control channel region is composed of a maximum of three OFDM symbols, the front-load DMRS is located in the fourth OFDM symbol as shown at k-2.

As described above, if the position of the front-load DMRS is determined by the maximum size of the settable control channel region, if the control channel is not partially or completely set, the decoding latency may be reduced. Therefore, the present invention proposes another method of setting the position of the front-load DMRS by the extended method of Opt.1.

For example, when the area of the control channel is composed of a maximum of two OFDM symbols, the front-load DMRS is fixed to the third OFDM symbol as in k-1, and the front-load DMRS is set as shown in FIG. The setting for fixing to the first OFDM symbol can be set as one option. If the two settings are changed according to the situation, the disadvantage of Option 1 can be compensated.

Specifically, setting the positions of a plurality of front-load DMRSs can be performed in various ways. For example, a semi-static method may be considered through upper layer signaling such as RRC. In addition, for example, a DMRS position may be set in the system information such as the MIB or the SIB and transmitted. It is also possible to consider, for example, how to set the DMRS position dynamically via the DCI. Alternatively, it is possible to set the position of the DMRS through a semi-persistent scheduling (SPS).

Next, Extended / Additional DMRS is explained. The front-loaded DMRS described above has difficulty in accurately estimating the channel because it is impossible to treble the channel that changes rapidly in time in the high-doppler situation. In addition, it is impossible to perform a cross-correlation correction on the frequency offset only by the front-loaded DMRS. Therefore, it is necessary to transmit additional DMRS to the back side on the time axis rather than the position where the front-loaded DMRS is transmitted in one slot.

FIGS. 1A to 1F show positions where Extended / Additional DMRSs are transmitted in the case where the slot length is 7 or 14 OFDM symbols, respectively. It should be noted that Figures 1 la-lf illustrate Extended / Additional DMRS for k-1, k-2, and k-3, respectively, where the location of the front-loaded DMRS is set as described in Figure 1k.

Figs. I-1 and I-2 illustrate an embodiment in which an extended / additional DMRS position is set by avoiding the location where the CRS is transmitted in the LTE system. This has the advantage of reducing the influence of interference in LTE-NR coexistence situations. However, in the case of I-3, the position of the front-loaded DMRS overlaps with the position of the CRS in the LTE system as in the case of k-3.

If the length of the slot is 7 OFDM symbols, the location of the Extended / Additional DMRS can be set to one, whereas if the length of the slot is 14 OFDM symbols, the Extended / Additional DMRS can be set to one, as shown in FIGS. The position needs to be set to two depending on the Doppler situation.

For example, referring to FIG. 1, the location of Extended / Additional DMRS can be set as shown in FIG. 1 - 2 in a rapidly changing channel environment. In an environment where a channel changes very rapidly, It is necessary to set the position of the additional DMRS as shown in Fig. 1-3. In the above embodiment, FIG. 1K and FIGS. 1 la-1f show the basic positions in which the DMRS is set. If the DMRS transmission layer increases, the location where the DMRS is transmitted may be additionally set. This will be described in more detail by way of the DMRS port multiplexing in FIG.

Also, in the case of Extended / Additional DMRS, a plurality of DMRSs are set on the time axis, which may cause an overhead problem of the DMRS. In this case, it is possible to reduce the overhead of the DMRS by setting the DMRS to have a low density on the frequency axis. Through the proposed DMRS structure, the above-described front-load DMRS and extended / additional DMRS can be operated more flexibly.

Specifically, the DMRS structure proposed by the present invention will be described with reference to FIG. In the present invention, a unit DMRS structure based on one OFDM symbol is proposed. The Unit DMRS structure based on one OFDM symbol is advantageous for setting the position of the reference signal for various TTIs (Transmission Time Intervals), as well as for supporting the low latency and the reference signal for the Ultra-Reliable Low Latency Communication (URLLC) It is also advantageous in terms of location setting, and may be advantageous in terms of scalability such as antenna port expansion.

As shown in FIG. 1M, 12 subcarriers may be included in one OFDM symbol based on PRB, which is the minimum transmission unit of data. The density of the DMRS SC (subcarrier) in one OFDM symbol is configurable as in the identification numbers 3m10, 3m20, and 3m30. The identification number 3m10 and the identification number 3m20 indicate the DMRS structure for the case where the DMRS SC is 4 and 8 in the 12 subcarriers respectively and the identification number 3m30 is the DMRS structure for the case where the DMRS SC is composed of all 12 subcarriers .

The configuration of even number of DMRS SCs at identification numbers 3m10 and 3m20 may be advantageous if orphan RE does not occur when Space Frequency Block Coding (SFBC) is considered as a transmit diversity scheme. For example, if the SFBC is transmitted on two antenna ports, and the RE on which the DMRS is transmitted on the frequency does not exist in a multiple of 2, one RE (orphan RE) can not be used.

SCs that are not used as DMRS SCs in identification numbers 3m10 and 3m20 can be mapped to data or other reference signals, or can be emptied for DMRS power boosting. Here, emptying the SC not used for the DMRS SC for DMRS power boosting can be used as a method for improving the performance of the DMRS channel estimation in a low SNR (Signal to Noise Ratio) region. The DMRS structure of FIG. 1m can be used not only for data channels but also for other channels (e.g., control channels).

Some subcarriers that are not DMRS transmitted at identification numbers 3m10 and 3m20 may be used as DC (direct current) subcarriers. However, in the case of the identification number 3m30, since the DMRS is transmitted in all the subcarriers, it is necessary to vacate a part in order to transmit the DC.

In addition, the DMRS structure of the identification number 3m10 may be replaced with the structure of the identification number 3m40 in consideration of the DC subcarrier. The DMRS SC shown in FIGS. 3M10 to 3M40 may be generated based on a PN (Pseudo-random) sequence or may be generated based on a ZC (Zadoff-Chu) sequence. An example of a more specific utilization method, the DMRS structure with identification number 3m10 (or 3m40) and 3m20, can be used in a CP-OFDM system.

And can be set and used at the same time-frequency position on the uplink / downlink. If the uplink / downlink has the same DMRS structure, the DMRS port of the uplink / downlink can orthogonal cancel due to better channel estimation than the TDD environment.

In contrast, the DMRS structure of identification number 3m30 is based on a Zadoff-Chu (ZC) sequence similar to LTE and can be used in a DFT-s-OFDM system in the uplink. This enables operation for low peak-to-average power ratio (PAPR) similar to LTE. However, the present invention is not limited to the method of utilizing the DMRS structure of FIG. 3M10 to 3M40. For example, the DMRS structure with identification number 3m30 may be used for both CP-OFDM / DFT-s-OFDM and uplink / downlink.

In FIG. 1N, a method of mapping an antenna port to the unit DMRS structure proposed in FIG. 1M will be described. For convenience, the antenna ports are denoted as p = A, B, C, D, etc. in FIG. Note, however, that the antenna port number may be represented by a different number. Here, the mapping of the antenna port is to support multiple layer transmission and rank. Therefore, the antenna port matching specified below can be replaced with the term layer transmission or rank support.

Specifically, the identification number 3n10 and the identification number 3n20 represent a case where two antenna ports are mapped to the DMRS structure of the identification number 3m10. The identification number 3n10 is a method of mapping two antenna ports p = A and B to FDM (Code Division Multiplexing) / CDM (Code Division Multiplexing) by applying an OCC (Orthogonal Cover Code) of length 2. In addition, the identification number 3n20 shows a method in which the antenna port p = A, B is mapped by the FDM scheme without applying the OCC. As will be described later, 3n40 and 3n60 are examples of mapping antenna ports by applying the FDD scheme without applying OCC as in 3n20.

Next, the identification number 3n30 and the identification number 3n40 are used to map two antenna ports to the DMRS structure of the identification number 3m20. The DMRS of identification number 3m20 can improve the channel estimation performance by increasing the density of the reference signal as compared with the identification number 3m10. The identification number 3n30 indicates a method of mapping two antenna ports p = A and B to FDM / CDM by applying OCC of length 2. The identification number 3n40 is mapped to p = A and B in the FDM scheme without OCC, Lt; / RTI >

Next, the identification number 3n50 and the identification number 3n60 show the case where four antenna ports are mapped to the DMRS structure of the identification number 3m20. In particular, if four antenna ports are supported, the subcarrier in which the DMRS is not transmitted in the DMRS structure having the identification number 3m20 may be empty to improve the channel estimation performance, and may be used for DMRS power boosting. The identification number 3n50 shows a method of mapping four antenna ports p = A, B, C, and D to FDM / CDM by applying OCC and FDM of length 2, = A, B, C, and D are mapped.

The application of the OCC in the frequency domain in the identification numbers 3n10, 3n30, and 3n50 has an advantage that the power imbalance problem does not occur. In case of LTE system, there is a power imbalance problem when OCC is applied in time, and OCC is different in every PRB in two PRBs.

Finally, since the identification number 3n70 is the DMRS structure of the identification number 3m30 and the 12 subcarriers are all used as the DMRS in the identification number 3m30, the method of supporting the orthogonal DMRS antenna port using ZC (Zadoff-Chu) is considered . At this time, assuming that the subcarrier spacing is 15 kHz as in LTE, up to 8 orthogonal antenna ports can be supported by applying 8 cyclic shift (CS) fields. Another way to utilize the 3m30 DMRS structure is to support four orthogonal antenna ports by FDM at four subcarrier intervals.

The present invention is not limited to the method in which the antenna port is mapped to the DMRS structure proposed in Figures 3n10 to 3n70. For example, in the case of the identification number 3m30, as shown in FIG. 3n80, the DMRS SC is FDM and supports up to 8 orthogonal antenna ports by applying four cyclic shift fields. In the operation method as shown in FIG. 3n80, all the subcarriers in one OFDM symbol are used in the case of supporting a high rank, but only a part of subcarriers in one OFDM symbol are used as reference signals in an environment using a low rank, Can be used for data transmission. For example, in case of transmission of rank 4 or less in FIG. 3n80, orthogonality may be supported by four CSs using only the reference signal of odd subcarriers, and the remaining six even subcarriers may be used for data transmission.

In FIG. 10, a larger number of antenna ports are mapped to the proposed Unit DMRS structure than that shown in FIG. 1M. In order to map a larger number of antenna ports than that shown in FIG. 1N, the TDM, FDM, and CDM may be additionally provided in the unit DMRS structure.

Referring to FIG. 3M20, as shown in FIG. 3O10, FIG. 3M20 is time-shifted in time so that a maximum of eight antenna ports can be mapped. 3O20 shows a case where TDM is performed with three OFDM symbols in time and a maximum of 16 antenna port mapping extensions are possible. In case of extending the orthogonal antenna port using TDM, the RS density on the frequency is maintained, but the density of the DMRS increases in the transmission unit. In order to keep the density of the DMRS in the transmission unit low, the higher rank is extended in the orthogonal antenna port by using FDM or CDM considering that the channel condition is very good and the channel selectivity of the channel on the frequency is low. Can be considered.

As shown in FIG. 3O30, FIG. 3m20 shows a method of mapping up to eight antenna ports by FDM on the frequency. Also, as shown in FIG. 3O40, it is possible to map up to 8 antenna ports by applying an OCC length of 8 to FIG. 3m20.

Next, when all the subcarriers are composed of DMRS SC as shown in FIG. 3M30, various antenna ports can be extended according to the antenna port mapping method applied in FIG. 3M30 as described above. If the subcarrier interval is assumed to be 15 kHz and the ZC sequence is CS to support 8 orthogonal antenna ports in FIG. 3M30, it is possible to extend 16 orthogonal antenna ports by applying TDM as shown in FIG.

If FDM is used at four subcarrier intervals in FIG. 3M30, up to four orthogonal antenna ports can be supported. However, if additional FDM is considered as shown in FIG. 3O30, if FDM is used at 8 subcarrier intervals, Support is available.

The present invention is not limited to the antenna port extending method shown in FIG. TDM, FDM, and CDM, and it is possible to extend an orthogonal antenna port in various ways. For example, as described above, when the number of antenna ports is increased by using only TDM as in FIG. 3O10 or FIG. 3O20, the density of the DMRS increases in the transmission unit. To overcome this disadvantage, a CDM with an OCC length of 4 may be applied based on two consecutive slots as shown in FIG. 3 o60 or TDM based on two consecutive slots as shown in FIG.

3O50 and 3O60, the time unit in which TDM or CDM is applied in FIGS. 3O50 and 3O60 is not limited to the slot. Also, unlike the method of mapping up to 8 antenna ports by applying the OCC length 8 as in FIG. 3O40, if the DMRS is generated as a ZC sequence, it is possible to support additional antenna ports using CS as shown in FIG. It is possible. As shown in FIG. 3 o 70, when the CS is used instead of the OCC, the RS density on the frequency is maintained.

[Example 1-2]

The first to second embodiments describe a method in which a base station sets up a DMRS structure suitable for a transmission environment among a plurality of DMRS structures. When a plurality of DMRS structures are supported as in the first embodiment of the present invention, and a DMRS structure suitable for the transmission environment can be set as in the first embodiment, the base station changes the DMRS structure according to the transmission environment The overhead of the reference signal can be optimized.

More specifically, in a low SNR or high-speed transmission environment, it is necessary to improve the channel estimation performance by setting a DMRS structure with a high overhead of a reference signal. On the other hand, in a high SNR or low-speed transmission environment, it is necessary to improve the transmission efficiency by setting a DMRS structure with a low reference signal overhead. Thus, if the reference signal is adaptively transmitted to the transmission environment, unnecessary overhead of the reference signal can be minimized and the performance of the system can be maximized.

Below, a method of establishing a DMRS structure suitable for a transmission environment will be described in more detail. The DMRS configuration suitable for the transmission environment of the base station proposed in the present invention can be semi-static or dynamically set. Also, a DMRS structure suitable for the transmission environment may be implicitly set.

First, a method for semi-static setting of a DMRS structure suitable for a transmission environment by a base station will be described. The simplest way to set the DMRS structure semi-static is to configure the structure of the DMRS through higher layer signaling.

More specifically, it is possible to signal information on different DMRS structures by setting a DMRS-StructureId in the RRC as shown in [Table 1-3] below. In [Table 1-3], maxDMRS-Structure shows the number of configurable DMRS structures, and each set value can represent different DMRS structures. In this manner, the DMRS structure can be set semi-static via the RRC, and the UE according to the embodiment of the present invention can grasp the structure of the currently transmitted DMRS based on the value set in the RRC.

[Table 1-3]

For example, the DMRS structure can be divided into two structures, a front-loaded DMRS and an extended / additional DMRS. In this case, the value of the maxDMRS-Structure in Table 1-3 may be set to one. For example, when the value of maxDMRS-Structure is 0, it indicates a front-loaded DMRS. If the value of maxDMRS-Structure is 1, it can be set to indicate Extended / Additional DMRS. In Table 1-3, the DMRS-sturctureID may be changed to DMRS-configureID or some other terminology.

As another example, the value of maxDMRS-Structure can be increased to 1 or more when there is more than one structure of Extended / Additional DMRS. Also, as described in the 1-1-1 embodiment, when the DMRS density in the frequency domain is adjusted in the Unit DMRS structure, the maxDMRS-Structure value can be set to a larger value.

As another example, the DMRS time / frequency density can be set through additional configuration by distinguishing between the front-loaded DMRS and the Extended / Additional DMRS configuration. More specifically, it may be set in the same manner as in [Table 1-4].

[Table 1-4]

As another example, a method for dynamically setting a DMRS structure suitable for a transmission environment by a base station will be described. If the information on the DMRS is set to the MAC CE in a manner similar to the method of setting the DMRS information in the RRC, information on the DMRS structure can be set more dynamically.

As another example, the simplest way to set the DMRS structure dynamically is to send information about the DMRS structure to the DCI. In this case, a DCI format in which fields for dynamically operating the DMRS structure is not applied may be separately defined for the basic operation. If the DMRS structure is set using the DCI, the DMRS structure can be changed dynamically, which improves the transmission efficiency. On the other hand, there is a disadvantage that DCI overhead occurs to operate it.

Hereinafter, a method of setting the DMRS structure using the DCI will be described in more detail. As the structure of various reference signals is supported, the number of bits required for signaling the structure of the various reference signals will increase in DCI. However, as shown in [Table 1-5] or [Table 1-6] Can be used to include information on the structure of the DMRS in the DCI field. For example, [Table 1-5] shows an example of operating the structure of two reference signals using 1 bit.

[Table 1-5]

As another example, [Table 1-6] shows an example in which the structure of the reference signal is operated by 4 bits using 2 bits. The low density2 field in [Table 1-6] may be set to a field that does not transmit DMRS if necessary. The application to this will be described in the first to third embodiments. As described in the embodiment 1-1, the DMRS structure may be determined by a combination of the signaling of [Table 1-5] and [Table 1-6] and the number of DMRS transmission layers used.

[Table 1-6]

Unlike the method of signaling the RS density using [Table 1-5] or [Table 1-6] as described above by transmitting information on the DMRS structure to the DCI, And may specifically signal the location in time that the DMRS can be transmitted as described above.

In the first embodiment, a position in time when the DMRS is transmitted is set based on a subframe and a starting point of the allocated data channel (ex, PDSCH) As shown in Fig. At this time, it is possible to signal to the DCI information about the position in time when the DMRS is transmitted.

For example, when a method in which the position of a time in which a DMRS is transmitted is set based on a subframe is used, when a value indicating a subframe duration is defined as x, the position of the DMRS is set to a unit of y = x / 2 Can be considered. In this case, it is possible to indicate whether the DMRS density is high or low in y units using only 1 or 2 bits.

More specifically, a lower DMRS density on a time axis may be a DMRS composed of one OFDM symbol, and a higher DMRS density on a time axis may be a DMRS composed of two OFDM symbols. Also, the DMRS structure may be determined by a combination of the number of DMRS transmission layers used together. A concrete example of this will be described with reference to Embodiment 1-1 described above.

Meanwhile, since it is inefficient to include a field indicating the DMRS structure in each transmission every time the data is transmitted, a field indicating the DMRS structure is transmitted through the DCI based on a preset time interval May be considered. However, in this case, since the structure of the reference signal can be changed only when the field indicating the DMRS structure is transmitted, it may be difficult to operate the DMRS structure more dynamically than the method of directing the DMRS structure at each transmission.

Finally, another example of a method of implicitly setting a DMRS structure suitable for a transmission environment of a base station will be described. The first method is to set different DMRS structures according to the transmission mode (TM).

More specifically, TM A is set as a reference signal having a high density, TM B is set as a reference signal having an average density on a time axis, and TM C can be set as a reference signal having a low density on a time axis. In this case, TM A can be set to TM to support high mobility, and TM C can be set to TM to support low latency.

Another way is to define two DCI formats in one TM. One of the two formats is set as a structure of a reference signal for transmitting the characteristics of the TM and the other is set in a fallback mode similar to DCI format 1A in LTE, Lt; / RTI > In this case, the UE can determine which DMRS structure is applied from the currently set TM mode or DCI format information.

The second method differs in the structure of the reference signal applied according to the modulation and coding scheme (MCS). More specifically, in a region where a low MCS is set, a reference signal having a high density may be mapped to improve channel estimation performance, and a reference signal having a low density may be mapped in a region where a high MCS is set. In this case, the UE can implicitly know the structure of the reference signal transmitted from the received MCS information.

The third method is a method in which different DMRS structures are set according to the frame structure. More specifically, the self-contained frame structure is set in an OFDM symbol ahead of the DMRS as shown in FIG. 1f-2-1 / 1fa-2-2, and in the general frame structure, It can be assumed that the DMRS is set to two OFDM symbols in time, as in -3-2.

As another setting method, when the PDCCH in the common search space is identified based on the LTE system, the structure of the reference signal for the PDSCH connected thereto can be mapped to have a high density. Similarly, when confirming a PDCCH in a UE-specific search space, a reference signal for a PDSCH connected to the PDSCH may be mapped to a reference signal having a low density as compared with a PDCCH connected to the common search space have. This is to improve the channel estimation performance because the common search space contains important information that all terminals should see. In this case, the UE implicitly recognizes the structure of the reference signal from the search space.

[Examples 1-3]

In the first to third embodiments, when a plurality of DMRS structures are supported unlike the existing LTE system, multiple-user transmissions using different DMRS structures can be supported, and each of the MU- We propose a method in which DMRS maintain orthogonality with each other. Even in the 5G system, there is a method of preventing the above problem by using a structure of a specific reference signal for terminals transmitting MU, but in this case, flexibility of MU transmission can be limited. Therefore, we propose two methods to maintain orthogonality between MU terminals when MU is transmitted between terminals using different DMRS structures.

The first method is a method of rate matching for overlapping parts in order to maintain orthogonality when different DMRS structures are overlapped. This method will be described in detail with reference to FIG. 1H. 1H-1 and 1H-2 show a method in which a base station performs rate matching for a region A in FIG. 1H-1 and transmits the same when a terminal using a different DMRS structure transmits MU .

This method is disadvantageous in that the base station must additionally signal the rate matching information to the terminal. The number of bits required for signaling may differ depending on the number of supported DMRS structures. Basically, when a plurality of DMRS structures are supported, the number of signaling bits needed to inform the DMRS structure of the other MUs is increased. However, as described in [Table 1-4] and [Table 1-5] in the 1-2 embodiment, when the DMRS structure is simplified by 2-4 types and operated, 1-2 bit signaling is applied to the terminal, The DMRS structure of the UE can be informed. At the same time, it is advantageous to perform power boosting on the reference signal of this part considering that different terminals rate-match the reference signal area where different DMRS structures overlap. However, this method is different from the LTE system in that the MU operation is no longer transparent to the UE.

The second method is to transmit an additional reference signal to the reference signal area where the DMRS structure overlaps to maintain orthogonality when different DMRS structures overlap. In other words, the second method is to set and transmit the same DMRS structure.

Referring to FIG. 1H, when a UE using different DMRS structures shown in FIGS. 1H-1 and 1H-2 is transmitted as an MU, the BS includes a reference signal in a region A of FIG. . In this case, it means that the base station using the DMRS structure of FIG. 1h-1 transmits using the DMRS structure of FIG. 1H-2. Unlike the first method, when using this method, there is an advantage that additional signaling is not required to the terminal using FIG. 1h-1.

On the other hand, the UE may vary depending on the implementation whether or not to additionally use the reference signal included in the area A in the channel estimation based on FIG. 1H-1. If the UE using the scheme of FIG. 1h-1 requires a low latency, the reference signal for the region A may not be used for fast signal processing. However, in this case, additional signaling may be required to indicate this. For example, the base station transmits information on the ACK / NACK timing to the UE through the DCI, so that the UE determines whether to use the reference signal for the region A on the basis of FIG. You can decide.

1H-3, 1H-4 and 1H-5 show a method of changing the DMRS density when a variable TTI (Transmission Time Interval) is applied. Also, we propose a method to maintain the orthogonality of the DMRS of the terminals at the MU.

More specifically, FIG. 1H-3 shows a case where a plurality of TTIs are combined and transmitted. At this time, it can be assumed that the same precoding is applied to the DMRS while a plurality of TTIs are transmitted. In particular, when the TTI duration is short, transmission of the DMRS with the same density on the frequency as shown in FIG. 1H-3 may be inefficient in terms of the overhead of the reference signal. Therefore, an example of changing the DMRS density in Figs. 1H-4 and 1H-5 is shown as a method of reducing the overhead of the reference signal.

First, a method of setting the DMRS for lowering the overhead of the reference signal in TTI-1 and TTI-2 in FIG. 1H-4 is possible. Alternatively, there may be a method in which the DMRS is not transmitted in the TTI-2 as shown in FIG. 1H-5. As described above, in the case of the MTI transmission in the TTI where the DMRS density is changed, the orthogonality may not be maintained due to the use of different DMRS structures by different terminals. In this case, as described above, in the case where different DMRS structures overlap, both of the two methods for maintaining orthogonality can be applied.

More specifically, when a rate matching method is applied, the base station signals the rate matching information to the UE before every TTI using the DCI. Alternatively, in the case of applying the second method, the base station may transmit to the different terminals in the TTI-2 without additional signaling, for example, as in the case of MU transmission in the TTI-2 of FIG. 1H-4 and FIG. 1H- The same DMRS structure can be set and transmitted. For example, the DMRS structure in TTI-1 can be transmitted in TTI-2.

In addition, we propose a method to efficiently support MUs between terminals using different OCC lengths. For example, a case where terminals using an OCC of length 2 and OCC of length 4 are transmitted to an MU will be described. For example, if 2-layer transmission is performed using OCC of length 4 based on [Table 1-2], 2-layer transmission is performed through ports 7 and 11, or 2-layer transmission is performed through ports 8 and 13 . This allows more orthogonal MU pairing than 2-layer transmission using ports 7 and 8 or 2-layer transmission using ports 11 and 13.

As described above, numbering from port 7 to port 14 is based on the LTE system in [Table 1-2], but this is an example for explanation. For example, the port number used in a 5G system may be different. Therefore, the proposed method can be applied based on the OCC sequence corresponding to each port in Table 1-2.

In order to perform the above-described embodiments of the present invention, the transmitter, the receiver and the processing unit of the UE and the base station are shown in FIGS. 1I and 1J, respectively. And a method of transmitting and receiving the base station and the terminal in order to provide a method of establishing the base station and the terminal. In order to accomplish this, the base station and the receiving unit, the processing unit, and the transmitting unit of the terminal must operate according to the embodiments, respectively.

1I is a block diagram illustrating an internal structure of a UE according to an embodiment of the present invention. 1 H, the terminal of the present invention may include a terminal receiving unit 1800, a terminal transmitting unit 1804, and a terminal processing unit 1802. The terminal receiving unit 1800 and the terminal may be collectively referred to as a transmitting unit 1804 in the embodiment of the present invention.

The transmitter / receiver of the terminal can transmit / receive signals to / from the base station. The signal may include control information and data. To this end, the transmitting and receiving unit of the terminal may include an RF (Radio Frequency) transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency. The transceiver of the terminal may receive the signal through the wireless channel, output the signal to the terminal processor 1802, and transmit the signal output from the terminal processor 1802 through the wireless channel.

The terminal processor 1802 may control a series of processes so that the terminal can operate according to the embodiment of the present invention described above. For example, when the terminal receiving unit 1800 receives the reference signal from the base station, the terminal processing unit 1802 can control to interpret the application method of the reference signal. Also, the terminal transmitting unit 1804 can transmit the reference signal in this manner.

1J is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention. As shown in FIG. 1I, the base station of the present invention may include a base station receiving unit 1901, a base station transmitting unit 1905, and a base station processing unit 1903. The base station receiving unit 1901 and the base station transmitting unit 1905 may be collectively referred to as a transmitting / receiving unit in the embodiment of the present invention.

The transmitting and receiving unit of the base station can transmit and receive signals to and from the terminal. The signal may include control information and data. To this end, the base transceiver unit may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency of the received signal.

The base transceiver unit may receive a signal through a wireless channel, output the signal to the base station processing unit 1903, and transmit the signal output from the base station processing unit 1903 through a wireless channel. The base station processor 1903 can control a series of processes so that the base station can operate according to the above-described embodiment of the present invention. For example, the base station processor 1903 can determine the structure of the reference signal and control the generation of configuration information of a reference signal to be transmitted to the terminal. Thereafter, the base station transmitter 1905 transmits the reference signal and configuration information to the terminal, and the base station receiver 1901 can receive the reference signal.

Also, according to an embodiment of the present invention, the base station processor 1903 can control processing for orthogonally supporting MU transmission among terminals using different DMRS structures. In addition, information necessary for control can be transmitted to the terminal using the base station transmitting unit 1905.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate the understanding of the present invention and are not intended to limit the scope of the present invention. That is, it will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible. Further, each of the above embodiments can be combined with each other as needed. For example, the base station and the terminal can be operated by combining the embodiments 1-1, 1-2, and 1-3 of the present invention. Although the above embodiments are presented on the basis of the FDD LTE system, other systems based on the technical idea of the above embodiment may be implemented in other systems such as a TDD LTE system, a 5G or NR system.

≪ Embodiment 2 >

In a wireless communication system, a base station must transmit a reference signal for estimating a channel. The UE can perform channel estimation using the reference signal and demodulate the received signal. Also, the UE can use the reference signal to grasp the channel state and feed back the channel state to the base station. Generally, when transmitting a reference signal, the transmission interval of the reference signal based on the frequency and time of the reference signal is determined in consideration of the maximum delay spread and the maximum Doppler spread of the channel. As the transmission interval of the reference signal becomes narrower, the channel estimation performance improves and the demodulation performance of the signal can be improved. However, this results in increasing the overhead of the reference signal and limiting the data transmission rate.

Conventionally, a 4G LTE system operating in a frequency band of 2 GHz uses reference signals such as a CRS (cell-specific reference signal) and a DMRS (demodulation reference signal) in the downlink. If the interval of the reference signal in the frequency domain is represented by a subcarrier interval m of an orthogonal frequency division multiplexing (OFDM) signal and the interval of the reference signal is represented by a symbol interval n of the OFDM signal in time, a normal cyclic prefix (m, n) = (3, 4), the transmission interval based on the frequency and time of the reference signal corresponding to antenna ports 1 and 2 is CRS. In case of DMRS assuming normal CP, the transmission interval based on the frequency and time of the reference signal is (m, n) = (5, 7).

Unlike the LTE system, the 5G wireless communication system considers a system operating in a higher frequency band than the 6GHz frequency band. Since the channel characteristics depend on the frequency band, it is necessary to newly design the reference signal in consideration of this in the 5G system. In 5G wireless communication, it is important to support low latency and high mobility. In addition, it is important to minimize the overhead of the reference signal in 5G systems.

In a wireless communication system, a base station must transmit a reference signal to a mobile station in order to measure a downlink channel condition. In the case of a 3GPP LTE-A (Long Term Evolution Advanced) system, a UE uses a CRS or a CSI-RS to transmit a channel state information between a Node B and a UE .

Several factors should be considered for the channel state, for example, the amount of interference in the downlink can be considered. The amount of interference in the downlink includes an interference signal and a thermal noise generated by the antennas included in each of the adjacent base stations and plays an important role in determining the channel condition of the downlink.

For example, when one transmission antenna included in one base station transmits a signal to one reception antenna included in one terminal, the terminal uses a reference signal received from the base station to transmit a signal per symbol The energy and the interference to be received together with the symbol during the interval in which the symbol is received should be determined and then the Es / Io should be determined. The determined Es / Io is converted to a data transmission rate or a value corresponding thereto, and is notified to the base station in the form of a channel quality indicator (CQI), thereby determining a transmission rate of the base station To make judgments.

In the LTE-A system, the UE feeds back information on the downlink channel state to the base station so that the base station can utilize the downlink scheduling. That is, the UE measures the channel state using the reference signal transmitted from the base station through the downlink, and feeds back the measured channel state information to the base station in a form defined by the LTE / LTE-A standard.

In the LTE / LTE-A, there are three channel state information (CSI) that the UE feeds back.

Rank Indicator (RI): The number of spatial layers that the UE can receive in the current channel state.

Precoder Matrix Indicator (PMI): Indicator for the preferred precoding matrix in the current channel state

Channel Quality Indicator (CQI): The maximum data rate that the terminal can receive in the current channel state. The CQI can be replaced by a SINR that can be used similar to the maximum data rate, a maximum error correction coding rate and modulation scheme, and data efficiency per frequency.

The RI, PMI, and CQI are related to each other and have a meaning. For example, the precoding matrix supported by LTE / LTE-A is defined differently for each rank. Therefore, the PMI value when RI has a value of 1 and the PMI value when RI has a value of 2 are interpreted differently even if their values are the same.

Also, the UE determines the CQI based on the assumption that the rank value and PMI value notified to the BS by the UE are applied to the BS. For example, when the UE reports RI_X, PMI_Y, and CQI_Z to the base station, it means that the UE can receive data according to the data rate corresponding to CQI_Z when rank is RI_X and precoding is PMI_Y. In this manner, the MS assumes a transmission scheme to the BS when calculating the CQI, so that the MS can obtain optimized performance when the BS actually transmits the transmission scheme.

In LTE / LTE-A, the UE's periodic feedback is set to one of the following four feedback modes depending on what information it contains:

One. Reporting mode 1-0: RI, wideband CQI (wCQI)

2. Reporting mode 1-1: RI, wCQI, PMI

3. Reporting mode 2-0: RI, wCQI, subband CQI (sCQI)

4. Reporting mode 2-1: RI, wCQI, sCQI, PMI

서브프레임이며, 오프셋은 N_OFFSET,CQI + N_OFFSET,RI이다.The feedback timing of each information for the four feedback modes is determined by values of N _pd , N _{OFFSET, CQI} , M _RI , and N _{OFFSET, RI} transmitted to a higher layer signal. In the feedback mode 1-0, the transmission period of wCQI is N _pd Frame, and the feedback timing is determined with the sub-frame offset value of N _{OFFSET and CQI} . Also, the transmission period of RI is

Frame, the offset is N _{OFFSET, CQI} + N _{OFFSET, RI} .

FIG. 2A is a diagram showing feedback timing of RI and wCQI in the case of N _pd = 2, M _RI = 2, N _{OFFSET, CQI} = 1, N _{OFFSET, and RI} = -1. In Fig. 2A, each timing represents a subframe index.

The feedback mode 1-1 differs from the mode 1-0 in that the wCQI and the PMI are transmitted together at the wCQI transmission timing for one of the antenna port, the two antenna ports, and the four antenna ports, .

서브프레임이며, 오프셋 값은 sCQI의 오프셋 값과 같이 N_OFFSET,CQI이다. 여기서,

로 정의되는데 K는 상위신호로 전달되며, J는 시스템 대역폭(bandwidth)에 따라 결정되는 값이다. 예를 들어, 10MHz 시스템에 대한 J 값은 3으로 정의된다. 결국, wCQI는 H번의 sCQI 전송마다 한번씩 이에 대체하여 전송된다. 그리고 RI의 주기는

서브프레임이며 오프셋은 N_OFFSET,CQI + N_OFFSET,RI이다. The feedback period for sCQI in feedback mode 2-0 is N _pd Frame, and the offset value is N _{OFFSET, CQI} . And the feedback period for wCQI is

Frame, and the offset value is N _{OFFSET, CQI} as the offset value of sCQI. here,

Where K is transmitted as an upper signal, and J is a value determined according to the system bandwidth. For example, the J value for a 10 MHz system is defined as 3. As a result, the wCQI is transmitted once instead of once every sCQI transmission of H times. And the cycle of RI

Subframe, offset is N _{OFFSET, CQI} + N _{OFFSET, RI} .

2B shows RI, sCQI, and wCQI feedback timings for N _pd = 2, M _RI = 2, J = 3 (10 MHz), K = 1, N _{OFFSET, CQI} = 1, N _OFFSET, Fig. The feedback mode 2-1 has the same feedback timing as mode 2-0 but the PMI is transmitted together with the wCQI transmission timing for the situation of one antenna port, two antenna ports, or four antenna ports I have.

The above-described feedback timing is for one, two, or four CSI-RS antenna ports, and as another example, the CSI-RS for any one of four antenna ports or eight antenna ports In the case of the allocated UE, two PMI information are fed back unlike the feedback timing. In this case, if the CSI-RS is allocated to one of the four antenna ports or the eight antenna ports, the feedback mode 1-1 may be divided into two submodes.

와 N_OFFSET,CQI + N_OFFSET,RI로 정의된다. For example, in the first submode, the RI is sent with the first PMI information and the second PMI information is sent with the wCQI. Here, the feedback period and offset for wCQI and the second PMI are defined as N _pd , N _{OFFSET, and CQI} , and the feedback period and the offset value for RI and the first PMI information are

And N _{OFFSET, CQI} + N _{OFFSET, RI} .

When both the first PMI (i1) and the second PMI (i2) are reported from the UE to the base station, the UE and the BS correspond to the combination of the first PMI and the second PMI in a codebook set The precoding matrix W (i1, i2) is a pre-coding matrix preferred by the UE.

In other words, when the precoding matrix corresponding to the first PMI is W1 and the precoding matrix corresponding to the second PMI is W2, the terminal and the base station determine that the precoding matrix preferred by the terminal is W1W2, which is the product of the two matrices Share information.

서브프레임이며 오프셋은 N_OFFSET,CQI + N_OFFSET,RI로 정의된다. When the feedback mode for 8 CSI-RS antenna ports is 2-1, precoding type indicator (PTI) information is added to the feedback information. At this time, the PTI is fed back with the RI,

Subframe, offset is N _{OFFSET, CQI} + N _{OFFSET, RI} .

이며 오프셋은 N_OFFSET,CQI이다. 여기서 H'은 상위신호로 전달된다. Specifically, when the PTI is 0, the first PMI, the second PMI, and the wCQI are both fed back. At this time, the wCQI and the second PMI are transmitted together at the same timing, the period is N _pd, and the offset is given as N _{OFFSET, CQI} . The period of the first PMI is

And the offset is N _{OFFSET, CQI} . Here, H 'is transmitted as an upper signal.

의 주기와 N_OFFSET,CQI의 오프셋을 가지고 피드백되며 H는 CSI-RS 안테나 포트 개수가 2인 경우와 같이 정의된다. On the other hand, if the PTI is 1, the wCQI is transmitted with the second wide PMI and the sCQI is fed back with the narrow second PMI at a separate timing. At this time, if the first PMI is not transmitted and the PTI is 0, the second PMI and the CQI are calculated after the latest PMI is calculated. The period and offset of the PTI and RI are the same as when the PTI is zero. The period of sCQI is defined as N _pd subframe, and the offset is defined as N _{OFFSET, CQI} . The wCQI and the second PMI

And the offset of N _{OFFSET and CQI} , and H is defined as the case where the number of CSI-RS antenna ports is two.

2C-1 and 2C-1 illustrate the case where N _pd = 2, M _RI = 2, J = 3 (10 MHz), K = 1, H '= 3, N _{OFFSET, CQI} = 1, N _OFFSET, The feedback timing in the case of PTI = 0 and PTI = 1, respectively, for the case of FIG.

LTE / LTE-A supports not only periodic feedback but also aperiodic feedback of the terminal. When a base station desires to acquire aperiodic feedback information of a specific UE, the Node B performs specific non-periodic feedback with an aperiodic feedback indicator included in downlink control information (DCI) for uplink data scheduling of the UE So that uplink data scheduling of the corresponding terminal is performed.

At this time, if the UE receives an indicator set to perform aperiodic feedback in the nth subframe, the UE performs uplink transmission including the aperiodic feedback information in the data transmission in the n + kth subframe. Here, k is a parameter defined in the 3GPP LTE Release 11 standard, 4 for frequency division duplexing (FDD), and defined as [Table 2-1] for time division duplexing (TDD). [Table 2-1] shows k values for each subframe number n in the TDD UL / DL configuration.

[Table 2-1]

If the aperiodic feedback is set, the feedback information includes RI, PMI, and CQI as in the case of periodic feedback, and RI and PMI may not be fed back depending on the feedback setting. The CQI may include both wCQI and sCQI, and may include only wCQI information.

As described above, unlike the LTE system, 5G wireless communication considers a system operating in a frequency band of 6 GHz or lower, as well as in a higher frequency band. In addition, low latency support and high mobility support are considered important in 5G wireless communication. In addition, it is important to minimize the overhead of the reference signal in 5G systems. Therefore, unlike the LTE system, the 5G system can support many reference signals suitable for the transmission environment.

In this manner, when a plurality of reference signals are supported, the UE may need additional feedback information for selecting a reference signal suitable for a transmission environment as well as RI, PMI, and CQI. Accordingly, the present invention provides a method for the UE to feed back information necessary for selecting a reference signal to the base station so that the environment adaptive transmission of the reference signal can be performed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Embodiments of the present invention will be described below as an example of an LTE or LTE-A system, but the embodiments of the present invention can be applied to other communication systems having a similar technical background or channel form. For example, 5G mobile communication technology developed after LTE-A (5G, new radio, NR) could be included. More specifically, the method of periodically or non-periodically feeding back the channel information may be different from the LTE method described above. Although the present invention has been described with reference to the DMRS, it can be applied to other reference signals. Therefore, the embodiments of the present invention can be applied to other communication systems by a person skilled in the art without departing from the scope of the present invention.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification. Hereinafter, the base station may be at least one of an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing communication functions. In the present invention, a downlink (DL) is a wireless transmission path of a signal transmitted from a base station to a mobile station, and an uplink (UL) is a wireless transmission path of a signal transmitted from a mobile station to a base station.

The feedback information for selecting a reference signal suitable for the transmission environment described below is expressed by the term " pilot density indicator (PDI) ". However, the term for PDI can be expressed in other terms depending on the intent of the user and the intended use of the reference signal. For example, terms such as reference-signal density indicator (RDI), Doppler frequency indicator (DFI), delay spread indicator (DSI), or SI (SINR indicator). The abbreviation defined as PDI is merely a specific example of the present invention and is not intended to limit the scope of the present invention in order to facilitate understanding of the present invention. That is, it is apparent to those skilled in the art that the present invention can be applied to a reference signal based on the technical idea of the present invention.

In the embodiment 2-1 of the present invention described below, feedback information that can be included in the PDI will be described. In Embodiment 2-2 of the present invention, a method of feeding back PDI will be described. In Embodiment 2-3 of the present invention, a method of operating a base station using a PDI will be described.

[Example 2-1]

The embodiment 2-1 describes information that can be included in the PDI, which is feedback information proposed in the present invention. As described above, a plurality of structures of the reference signals required according to the transmission environment can be supported.

More specifically, in an environment where the degree of Doppler effect is high, it is necessary to enhance the channel estimation performance by increasing the density of the reference signal on the transmission time axis. On the other hand, in an environment in which the degree of the Doppler effect is small (hereinafter, it is used in combination with the term "Low Doppler"), it is necessary to reduce the overhead of the reference signal by lowering the density of the reference signal on the transmission time axis. In the high delay environment, it is necessary to improve the channel estimation performance by increasing the density of the reference signal on the transmission frequency axis. On the other hand, in the low delay environment, it is necessary to reduce the overhead of the reference signal by lowering the density of the reference signal on the transmission frequency axis. Also, in order to guarantee the channel estimation performance in the Low SNR (Signal to interference plus noise ratio) environment, the reference signal structure with high density is required. In the high SNR environment, It needs to be reduced.

The Doppler information, the channel delay information, and the SINR information that determine the structure of the reference signal are all information that the terminal can grasp through measurement. Therefore, PDI, which is feedback information proposed in the present invention, may include Doppler information, channel delay information, and SINR information. However, the information that can be included in the PDI of the present invention is not limited to the above information.

The UE may feed back the measured Doppler information, channel delay information, and SINR information to inform about the reference signal structure preferred in the channel environment. In the present invention, the PDI may include both Doppler information, channel delay information, and SINR information, or may include only some information.

More specifically, based on the information included in the PDI, a description will be given of a reference signal structure suitable for each situation.

If the PDI includes Doppler information, the UE can determine the structure of the reference signal suitable for the channel environment by measuring the Doppler frequency. For example, the UE can measure the Doppler frequency by performing time correlation on the basis of the reference signal. If Doppler frequency (Hz) is larger than X as shown in Equation 1 below, it can be indicated that transmission of a high-density reference signal on the transmission time axis is required.

[Equation 1]

Doppler frequency> X

를 나타낸다. 따라서, Doppler frequency는 캐리어 주파수(carrier frequency)와 단말 속도에 영향을 받음을 알 수 있다. In Equation (1), X (Hz) represents a threshold value for the Doppler frequency. And the Doppler frequency can be expressed as Doppler frequency = f * v / c. Where f is the carrier frequency (Hz), v (m / s) is the terminal speed, c is the speed of light

. Therefore, it can be seen that the Doppler frequency is influenced by the carrier frequency and the terminal speed.

For example, for f = 2.5 GHz and v = 350 km / h, the Doppler frequency is 810 Hz. For example, when the Doppler frequency is considered to be a High Doppler environment with a frequency of 800 Hz or higher, the threshold X for the Doppler frequency may be set to 800 Hz.

Unlike the LTE system, the 5G system considers the terminal speed up to 500 km / h, so the above method of adaptively changing the structure of the reference signal in consideration of the terminal speed can be very effective. In the present invention, when the Doppler frequency is greater than X as shown in Equation (1), a one-bit indicator may be fed back to indicate that transmission of a reference signal with a high density on the time axis is required.

Next, when the channel delay information is included in the PDI, the UE can determine the structure of the reference signal suitable for the channel environment by measuring the channel delay. For example, the UE can measure channel delay information using various methods based on a reference signal.

For example, the UE can measure the PDP (Power Delay Profile) by performing correlation on the frequency based on the reference signal. Delay spread information such as root mean square (RMS) delay spread and maximum delay spread can be obtained from the PDP information. If the delay spread (sec) is larger than Y as shown in Equation (2) below, it can be indicated that transmission of a reference signal having a high density on the transmission frequency is required.

&Quot; (2) "

Delay spread> Y

In Equation (2), Y (sec) represents a threshold for a delay spread. And the delay spread can be the RMS delay spread or the maximum delay spread. If it is based on the RMS delay spread, Y is set based on the RMS delay spread value and can be set differently based on the maximum delay spread value.

In general, the reference signal in the existing LTE system is designed assuming worst case for channel delay. Therefore, in a low channel delay environment, the reference signal having a lower density may be used to improve the transmission efficiency .

In addition, the 5G system considers the system not only in a frequency band of 6 GHz or lower but also in a higher frequency band, and accordingly, considering various subcarrier spacing support, unlike the existing LTE system, You need to design.

In the present invention, when the delay spread is larger than Y as in Equation (2), one bit indicator may be fed back to indicate that transmission of a reference signal with a high density on the frequency axis is required. However, if the reference signal is designed with a worst case assumption for the channel delay in the 5G system, an additional indication of delay information may not be required.

Finally, when the channel SINR information is included in the PDI, the UE can determine the structure of the reference signal suitable for the channel environment through the SINR measurement. For example, the UE can measure the SINR using various methods based on the received signal. If the SINR is greater than Z as shown in Equation (3) below, the structure of the reference signal having a high density can be indicated.

&Quot; (3) "

SINR> Z

In Equation (3), Z represents a threshold for SNR. In general, it is important to maintain system performance by improving the channel estimation performance using a reference signal having a high density in a low SINR range (-10 to 0 dB). In one embodiment, the threshold Z = 0 dB for the SINR may be set.

In the present invention, when SINR is greater than Z as in Equation (3), one bit indicator may be fed back to indicate that a reference signal having a high density is preferred. However, in Equation (3), the SINR is replaced with the CQI index defined in Table 7.2.3-1 of 3GPP LTE standard TS.36.213, the maximum error correction coding rate and modulation scheme, data efficiency per frequency, and the like It is possible.

If SINR is replaced with a CQI index in Equation (3), it is advantageous to feedback structure information of a reference signal implicitly through CQI feedback without using additional bits . In one embodiment, when the lowest CQI index is fed back, it can be indicated that a reference signal having a high density is preferred.

It is possible to determine which reference signal structure the terminal desires based on the information included in the PDI which is the feedback information proposed by the present invention and the information included in the PDI from the embodiment 2-1, A method of determining whether or not the transmission is required is described with reference to Equations 1 to 3 above. According to the above situation, the information necessary for the terminal to feed back to the base station may be set to 1 to 3 bits.

However, if a plurality of threshold values are set in Equations 1 to 3 as required, the structure of the reference signal preferred by the terminal can be further subdivided according to the threshold values. In this case, the number of bits of information necessary for the terminal to feed back to the base station may increase.

For example, if two thresholds X1 and X2 for the Doppler frequency are set as in Equation (4), the structure of the reference signal preferred by the UE can be classified into three types.

&Quot; (4) "

Doppler frequency> X1 (4-1)

 X2? Doppler frequency? X1 (4-2)

Doppler frequency <X2 (4-3)

In Equation (4), when there are three reference signal structures according to the density on the transmission time axis, Equation 4-1 indicates that the reference signal with the highest density is preferred over the transmission time axis, , And that Equation 4-3 indicates that the reference signal with a low density is preferred over the transmission time axis. The above method can also be applied to equations (2) and (3).

[Example 2-2]

The embodiment 2-2 describes a method of feeding back a pilot density indicator (PDI), which is feedback information proposed by the present invention, to a base station. In the LTE / LTE-A as described above, the UE may feed back PDI along with RI, PMI, and CQI, which are channel state information fed back to the base station.

First, in the case of using aperiodic feedback, the base station sets up an aperiodic feedback indicator included in the downlink control information for uplink data scheduling of the corresponding terminal to perform PDI feedback, so that PDI information is added to the uplink data of the corresponding terminal .

Next, consider the case of using aperiodic feedback. In the case of aperiodic feedback, the number of bits usable for feedback can be limited. Therefore, information required for feedback can be limited to 1 to 3 bits using Equations 1 to 3 of the above-mentioned Embodiment 2-1. The PDI feedback method proposed by the present invention can be classified as follows based on the CQI feedback of the LTE system.

One. When feedback is based on a wideband CQI (wCQI)

2. When feedback is performed based on a subband CQI (sCQI)

3. Separate feedback to wCQI and sCQI

Based on the assumption of FIG. 2A, FIG. 2D-1 shows a case where feedback is performed based on wCQI among the PDI feedback methods. 2D-1 shows that the PDI is transmitted together whenever the wCQI is fed back. In this case, a reference signal suitable for the channel state can be determined on the basis of the entire band.

Based on the assumption of FIG. 2B, FIG. 2D-2 shows a case of feedback based on sCQI among the PDI feedback methods. In this case, the reference signal suitable for the channel condition can be determined on the basis of the narrow band.

Based on the assumption of FIG. 2B, FIG. 2D-3 illustrates a case where the PDI feedback is separately fed back to wCQI and sCQI. In this case, the reference signal suitable for the channel condition of the base station can be determined on the basis of the wide band or the narrow band.

[Example 2-3]

The second to third embodiments describe the operation of the base station when the PDI, which is the feedback information proposed in the present invention, is fed back from the terminal to the base station. The base station can distinguish between the supportable reference signal and the environment as shown in [Table 2-2] or [Table 2-3] below.

[Table 2-2] shows an example of operating the structure of the reference signal in two, and [Table 2-3] shows an example of operating the structure of the reference signal in four. For example, if there are two structures of the reference signals that can be supported, it is possible to distinguish between the two reference signals according to [Table 2-2].

[Table 2-2]

As another example, when there are four types of structures of the reference signal that can be supported more variously, it is possible to distinguish the condition of each reference signal according to [Table 2-3].

[Table 2-3]

More specifically, the structure of the reference signal for [Table 2-3] is shown in FIG. 2E. When the transmission environment requires a low latency or a low Doppler environment, it is possible to use a structure of a reference signal having a low density on the time axis as shown in FIG. 2e-1. On the other hand, in an environment in which the transmission environment is low, it is possible to use the structure of the reference signal having a low density on the frequency as shown in FIG. 2E-2. On the other hand, in the high delay environment, it is possible to use the structure of the reference signal having a high frequency density as shown in FIG. 2e-3. In a high Doppler environment or a low SINR environment, it is possible to use a structure of a reference signal having a high density as shown in FIG. 2e-4.

In other words, it is possible to interpret as follows. The structure of FIG. 2E-1 shows the structure of a reference signal corresponding to low latency / low Doppler. The structure of FIG. 2E-2 shows the structure of the reference signal corresponding to the Low delay / High SINR. The structure of FIG. 2E-3 shows the structure of a reference signal corresponding to a high delay / high SINR. And the structure of FIG. 2E-4 shows the structure of the reference signal corresponding to the High Doppler / Low SINR.

A method of determining the structure of the reference signal suitable for the current environment when the base station receives the PDI, which is the feedback information proposed by the present invention, from the UE according to the embodiment 2-3 is exemplified. However, the method of determining the structure of the reference signal suitable for the transmission environment through PDI reception may vary depending on the structure of the reference signal supported by the base station as described above.

[Example 2-4]

In the present invention, when a plurality of reference signals are supported, a method of feeding back information on a reference signal preferred by the terminal is proposed. In the second to fourth embodiments, when a plurality of reference signals are supported, a method of setting a type and number of reference signals that can be supported by a specific terminal to a UE capability is proposed.

More specifically, the base station can inform the terminal of the type of the reference signal that can be set through the UE capability signaling, and the terminal can feedback information about the reference signal preferred by the terminal within the settable reference signal type . The fact that the base station informs the terminal of the type of the reference signal that can be set through the UE capability signaling is advantageous in that the terminal can easily select the reference signal preferred by the terminal within the type of the reference signal.

For example, the type and number of configurable reference signal structures may vary depending on the slot structure. More specifically, different types of reference signals can be used for a structure in which 14 symbols are used as one slot and a structure in which 7 symbols are used as one slot. Further, in the structure of the minislot, the structure or kind of the reference signal different from the slot structure described above can be used.

Also, the types of reference signals usable according to the terminal implementation may be limited on the terminal side as well. Specifically, a specific terminal may restrict the method of implementing the channel estimation on the reference signal, so that the structure of all the reference signals may not be supported.

Therefore, as in the case of the proposed method, a method in which a base station informs a terminal of a type of a reference signal that can be set through UE capability signaling, and a terminal selects a reference signal preferred by the terminal within the available reference signal type, Required in supported environments. Here, the UE capability signaling may be set in an RRC (Radio Resource Control) signaling, which is an upper layer signal.

In order to perform the above-described embodiments of the present invention, the transmitter, receiver and processing unit of the terminal and the base station are shown in FIGS. 2F and 2G, respectively. A method for transmitting / receiving a base station and a terminal to perform transmission and reception of a pilot density indicator (PDI), which is feedback information proposed in the present invention, is shown from the second to the first embodiment to the second and third embodiments, The receiving unit, the processing unit, and the transmitting unit of the base station and the terminal must operate according to the embodiment, respectively.

2F is a block diagram illustrating an internal structure of a UE according to an embodiment of the present invention. As shown in FIG. 2F, the terminal of the present invention may include a terminal receiving unit 1800, a terminal transmitting unit 1804, and a terminal processing unit 1802.

The terminal reception unit 1800 and the terminal transmission unit 1804 may be collectively referred to as a transmission / reception unit in the embodiment of the present invention. The transmitter / receiver of the terminal can transmit / receive signals to / from the base station. The signal may include control information and data. To this end, the transmitting and receiving unit of the terminal may include an RF (Radio Frequency) transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency.

The transceiver of the terminal may receive the signal through the wireless channel, output the signal to the terminal processor 1802, and transmit the signal output from the terminal processor 1802 through the wireless channel.

The terminal processor 1802 may control a series of processes so that the terminal can operate according to the embodiment of the present invention described above. For example, the terminal processing unit 1802 measures and interprets information that may be included in the PDI. In addition, the terminal processor 1802 may control the terminal transmitter 1804 to transmit the PDI information to the base station. Also, according to an embodiment of the present invention, the terminal processor 1802 can determine the transmission timing of the PDI periodically or non-periodically and control the PDI transmission timing.

2G is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention. As shown in FIG. 2G, the base station of the present invention may include a base station receiving unit 1901, a base station transmitting unit 1905, and a base station processing unit 1903. The base station receiving unit 1901 and the base station transmitting unit 1905 may be collectively referred to as a transmitting / receiving unit in the embodiment of the present invention.

The transmitting and receiving unit of the base station can transmit and receive signals to and from the terminal. The signal may include control information and data. To this end, the transmitting and receiving unit may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, an RF receiver for low-noise amplifying the received signal and down-converting the frequency.

The base transceiver unit may receive a signal through a wireless channel, output the signal to the base station processing unit 1903, and transmit the signal output from the base station processing unit 1903 through a wireless channel.

The base station processor 1903 can control a series of processes so that the base station can operate according to the above-described embodiment of the present invention. For example, the base station receiving unit 1901 receives PDIs fed back by the UE. The base station processor 1903 may analyze the PDI information received from the terminal and determine the structure of a reference signal suitable for the transmission environment. Then, the base station processor 1903 controls the base station transmitter 1905 to transmit the corresponding reference signal based on the structure of the reference signal selected based on the PDI. Also, according to an embodiment of the present invention, the base station processor 1903 can perform setting for controlling periodic or aperiodic reception of the PDI and controlling the PDI.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate the understanding of the present invention and are not intended to limit the scope of the present invention. That is, it will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible.

In addition, each of the above embodiments can be combined and operated as needed. For example, the embodiments 2-1, 2-2, and 2-3 may be combined with each other to operate through the base station and the terminal. Also, although the above embodiments are presented on the basis of the FDD LTE system, other systems based on the technical idea of the above embodiments may be implemented in other systems such as a TDD LTE system, a 5G or NR system.

&Lt; Third Embodiment >

In a wireless communication system, especially in a conventional LTE system, HARQ (Hybrid Automatic Repeat reQuest) ACK (Acknowledgment) or NACK (Negative Acknowledgment) information indicating success of data transmission in uplink after 3 ms after receiving downlink data To the base station. For example, if the HARQ ACK / NACK information of the physical downlink shared channel (PDSCH) received in the subframe n from the BS to the UE is a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) in the subframe n + To the base station.

Also, in a frequency division duplex (LTE) system, a base station may transmit downlink control information (DCI) including uplink resource allocation information to a mobile station or request retransmission through a physical hybrid ARQ indicator channel (PHICH) When the uplink data transmission scheduling is received in the subframe n, the UE performs uplink data transmission in the subframe n + 4. That is, the PUSCH transmission is performed in the subframe n + 4. In the LTE system using TDD (Time Division Duplex), the HARQ ACK / NACK transmission timing and the PUSCH transmission timing are different according to the uplink-downlink subframe setting in the LTE system using the FDD. , Which is performed according to a predetermined rule.

In the LTE system using FDD or TDD, the HARQ ACK / NACK transmission timing or the PUSCH transmission timing is predetermined according to the case where the time required for signal processing of the base station and the terminal is about 3 ms. However, if the signal processing time is reduced to 1 ms or 2 ms, the delay time for data transmission will be reduced. The reduction of the signal processing time to 1 ms or 2 ms may be accomplished by limiting the number of allocated physical resource blocks (PRBs), Modulation and Coding Scheme (MCS), and Transport Block Size (TBS).

Efforts are underway to develop an improved 5G or pre-5G communication system to meet the growing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G network) communication system or a system after a LTE system (Post LTE).

To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In order to mitigate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave, in the 5G communication system, beamforming, massive MIMO, full-dimension MIMO (FD-MIMO ), Array antennas, analog beam-forming, and large scale antenna technologies are being discussed.

Further, in order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP) and interference cancellation (CoMP) Have been developed.

In addition, in the 5G system, the Advanced Coding Modulation (ACM) scheme, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), the advanced connection technology, Filter Bank Multi Carrier (FBMC) (non-orthogonal multiple access), and SCMA (sparse code multiple access).

On the other hand, the Internet is evolving into an Internet of Things (IoT) network in which information is exchanged between distributed components such as objects in a human-centered network where humans generate and consume information. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired / wireless communication, network infrastructure, service interface technology and security technology are required. In recent years, sensor network, machine to machine , M2M), and MTC (Machine Type Communication).

In the IoT environment, an intelligent IT (Internet Technology) service can be provided that collects and analyzes data generated from connected objects to create new value in human life. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, and advanced medical service through fusion of existing information technology . &Lt; / RTI &gt;

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, machine to machine (M2M), and machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antennas, which are 5G communication technologies will be. The application of the cloud RAN as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

As described above, a plurality of services can be provided to a user in the communication system, and a method and a device using the method that can provide each service within the same time interval in accordance with the characteristics to provide the plurality of services to the user are required .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In this specification, it will be understood that each block of the process flow diagrams and combinations of flow diagram diagrams may be performed by computer program instructions. These computer program instructions may be loaded into a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, so that those instructions, which are executed through a processor of a computer or other programmable data processing apparatus, Thereby creating means for performing functions. These computer program instructions may also be stored in a computer usable or computer readable memory capable of directing a computer or other programmable data processing apparatus to implement the functionality in a particular manner so that the computer usable or computer readable memory The instructions stored in the block diagram (s) are also capable of producing manufacturing items containing instruction means for performing the functions described in the flowchart block (s). Computer program instructions may also be stored on a computer or other programmable data processing equipment so that a series of operating steps may be performed on a computer or other programmable data processing equipment to create a computer- It is also possible for the instructions to perform the processing equipment to provide steps for executing the functions described in the flowchart block (s).

In addition, each block may represent a portion of a module, segment, or code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative implementations, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may actually be executed substantially concurrently, or the blocks may sometimes be performed in reverse order according to the corresponding function.

Herein, the term &quot; part &quot; used in the present embodiment means a hardware component such as software or an FPGA or an ASIC, and 'part' performs certain roles. However, 'part' is not meant to be limited to software or hardware. &Quot; to &quot; may be configured to reside on an addressable storage medium and may be configured to play one or more processors. Thus, by way of example, 'parts' may refer to components such as software components, object-oriented software components, class components and task components, and processes, functions, , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and components may be further combined with a smaller number of components and components or further components and components. In addition, the components and components may be implemented to play back one or more CPUs in a device or a secure multimedia card. Also, in an embodiment, 'to' may include one or more processors.

At least one service of Enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (mMTC) and Ultra-Reliable and Low-latency Communications (URLLC) may be provided to the terminal in a wireless communication system including the fifth generation. The services can be provided to the same terminal during the same time period. In the embodiment, the eMBB may be a high-speed transmission of high-capacity data, the mMTC may be a terminal power minimization and a connection of a plurality of terminals, and the URLLC may be a service aiming at high reliability and low latency. The above three services may be a major scenario in a LTE system or a system such as 5G / NR (new radio, next radio) after LTE. In the embodiment, coexistence of eMBB and URLLC, coexistence of mMTC and URLLC, and apparatus using the same will be described.

When the BS schedules data corresponding to the eMBB service in a specific transmission time interval (TTI), when the situation of transmitting URLLC data occurs in the TTI, the eMBB data is scheduled and transmitted The generated URLLC data can be transmitted without transmitting a part of the eMBB data. Here, the UEs scheduled for the eMBB and the UEs scheduled for the URLLC may be the same UE or different UEs.

In such a case, there is a possibility that the eMBB data is damaged because a part of the eMBB data that has already been scheduled and transmitted is not transmitted. In this case, it is necessary to determine a method of processing a signal received from a terminal that has been scheduled for eMBB or a terminal that is scheduled for URLLC and a signal reception method.

Therefore, in the embodiment of the present invention, when information according to eMBB and URLLC is shared by sharing some or all frequency bands, information is simultaneously scheduled according to mMTC and URLLC, or information according to mMTC and eMBB is simultaneously scheduled , Or coexistence between heterogeneous services that can transmit information according to each service when the information according to eMBB, URLLC and mMTC are scheduled at the same time.

Hereinafter, the base station may be at least one of an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing communication functions.

In the present invention, a downlink (DL) is a wireless transmission path of a signal transmitted from a base station to a mobile station, and an uplink (UL) is a wireless transmission path of a signal transmitted from a mobile station to a base station. In the following, embodiments of the present invention will be described as an example of an LTE or LTE-A system, but embodiments of the present invention may be applied to other communication systems having a similar technical background or channel form. For example, 5G mobile communication technology developed after LTE-A (5G, new radio, NR) could be included. In addition, embodiments of the present invention may be applied to other communication systems by a person skilled in the art without departing from the scope of the present invention.

In the LTE system, an OFDM (Orthogonal Frequency Division Multiplexing) scheme is used in a downlink (DL) and a Single Carrier Frequency Division Multiple (SC-FDMA) scheme is used in an uplink Access) method.

The uplink refers to a wireless link that transmits data or control signals to a terminal (User Equipment, UE) or a mobile station (MS) to a base station (eNode B or base station (BS) In the above multiple access scheme, time / frequency resources to transmit data or control information for each user are not overlapped with each other, that is, orthogonality So that data or control information of each user can be distinguished.

The LTE system adopts a Hybrid Automatic Repeat reQuest (HARQ) scheme in which a physical layer resends data when a decoding failure occurs in an initial transmission. In the HARQ scheme, if a receiver fails to correctly decode (decode) data, the receiver transmits information indicating a decoding failure (NACK: Negative Acknowledgment) to the transmitter so that the transmitter can retransmit the corresponding data in the physical layer. The receiver combines the data retransmitted by the transmitter with the previously decoded data to improve data reception performance. In addition, when the receiver correctly decodes the data, an acknowledgment (ACK) indicating the decoding success is transmitted to the transmitter so that the transmitter can transmit new data.

FIG. 3A is a diagram illustrating a basic structure of a time-frequency domain, which is a radio resource region in which the data or control channel is transmitted in the downlink in an LTE system or a similar system.

Referring to FIG. 3A, the horizontal axis indicates time domain and the vertical axis indicates frequency domain. The minimum transmission unit in the time domain is an OFDM symbol, and N _symb (102) OFDM symbols constitute one slot 106, and two slots form one subframe 105. The length of the slot is 0.5 ms and the length of the subframe is 1.0 ms. The radio frame 114 is a time domain including 10 subframes. The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the total system transmission bandwidth is composed of a total of N _BW (104) subcarriers. However, such specific values can be applied variably.

In a time-frequency domain, a basic unit of a resource can be represented by an OFDM symbol index and a subcarrier index as a resource element (RE) 112. A resource block (RB or Physical Resource Block) 108 may be defined as N _symb (102) consecutive OFDM symbols in the time domain and N _RB (110) consecutive subcarriers in the frequency domain. Thus, one RB 108 in one slot may include N _symb x N _RB REs 112.

In general, the minimum frequency-domain allocation unit of data is the RB. In the LTE system, N _symb = 7, N _RB = 12, and N _BW and N _RB may be proportional to the bandwidth of the system transmission band. The data rate increases in proportion to the number of RBs scheduled to the UE. The LTE system can define and operate six transmission bandwidths. In the case of an FDD system in which the downlink and the uplink are classified by frequency, the downlink transmission bandwidth and the uplink transmission bandwidth may be different from each other. The channel bandwidth represents a radio frequency (RF) bandwidth corresponding to the system transmission bandwidth.

[Table 3-1] shows correspondence between system transmission bandwidth and channel bandwidth defined in LTE system. For example, an LTE system with a 10 MHz channel bandwidth can have a transmission bandwidth of 50 RBs.

[Table 3-1]

The downlink control information may be transmitted within the first N OFDM symbols in the subframe. In the embodiment, N = {1, 2, 3} in general. Therefore, the N value can be variably applied to each subframe according to the amount of control information to be transmitted in the subframe. The transmitted control information may include a control channel transmission period indicator indicating how many OFDM symbols control information is transmitted, scheduling information for downlink data or uplink data, and HARQ ACK / NACK information.

In the LTE system, scheduling information for downlink data or uplink data is transmitted from a base station to a mobile station through downlink control information (DCI). The DCI is defined according to various formats, and it is determined according to each format whether the scheduling information (UL grant) for the uplink data or the scheduling information (DL grant) for the downlink data, whether the size of the control information is compact DCI , Whether to apply spatial multiplexing using multiple antennas, whether or not DCI is used for power control, and the like. For example, DCI format 1, which is scheduling control information (DL grant) for downlink data, may include at least one of the following control information.

- Resource allocation type 0/1 flag: Indicates whether the resource allocation scheme is Type 0 or Type 1. Type 0 allocates resources by resource block group (RBG) by applying bitmap method. In the LTE system, the basic unit of scheduling is an RB represented by time and frequency domain resources, and the RBG is composed of a plurality of RBs and becomes a basic unit of scheduling in the type 0 scheme. Type 1 allows a specific RB to be allocated within the RBG.

- Resource block assignment: Indicates the RB allocated to the data transmission. The resources to be represented are determined according to the system bandwidth and the resource allocation method.

- Modulation and coding scheme (MCS): Indicates the modulation scheme used for data transmission and the size of the transport block, which is the data to be transmitted.

- HARQ process number: Indicates the HARQ process number.

- New data indicator: Indicates whether HARQ is initial transmission or retransmission.

- Redundancy version: Indicates the redundancy version of HARQ.

- Transmit Power Control (TPC) command for PUCCH for Physical Uplink Control CHannel: Indicates a transmission power control command for the uplink control channel PUCCH.

The DCI is a physical downlink control channel (PDCCH) (or control information), or an Enhanced PDCCH (Enhanced PDCCH) (or enhanced control information, hereinafter referred to as &quot; It may be used on a mixed basis).

Generally, the DCI is scrambled with a specific Radio Network Temporary Identifier (RNTI) (or a mobile station identifier) independently of each mobile station, and a cyclic redundancy check (CRC) is added, channel-coded and then composed of independent PDCCHs . In the time domain, the PDCCH is mapped and transmitted during the control channel transmission period. The frequency domain mapping position of the PDCCH is determined by the identifier (ID) of each terminal, and can be transmitted over the entire system transmission band.

The downlink data may be transmitted on a physical downlink shared channel (PDSCH), which is a physical channel for downlink data transmission. PDSCH may be transmitted after the control channel transmission interval, and scheduling information such as a specific mapping position and a modulation scheme in the frequency domain is determined based on the DCI transmitted through the PDCCH.

The base station notifies the UE of a modulation scheme and a transport block size (TBS) to be transmitted to the UE through the MCS among the control information included in the DCI. In an embodiment, the MCS may be composed of 5 bits or more or fewer bits. The TBS corresponds to a size before channel coding for error correction is applied to data (transport block, TB) to be transmitted by the base station.

The modulation schemes supported by the LTE system are QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), and 64QAM, and the respective modulation order (Qm) corresponds to 2, 4, and 6. That is, 2 bits per symbol for QPSK modulation, 4 bits per symbol for 16QAM modulation, and 6 bits per symbol for 64QAM modulation. In addition, 256QAM or more modulation method can be used according to the system modification.

3B is a diagram illustrating a basic structure of a time-frequency domain, which is a radio resource region in which an uplink data or control channel is transmitted in an LTE-A system.

Referring to FIG. 3B, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an SC-FDMA symbol 202, and N _symb ^UL SC-FDMA symbols can be gathered to form one slot 206. [ Then, two slots form one subframe 205. The minimum transmission unit in the frequency domain is a subcarrier, and the total system transmission bandwidth 204 is composed of a total of N _BW subcarriers. N _BW may have a value proportional to the system transmission band.

The basic unit of resources in the time-frequency domain is a resource element (RE) 212, which can be defined as an SC-FDMA symbol index and a subcarrier index. A resource block pair (RB pair) 208 may be defined as N _symb ^UL consecutive SC-FDMA symbols in the time domain and N _sc ^RB consecutive subcarriers in the frequency domain. Therefore, one RB consists of N _symb ^UL x N _sc ^RB REs. In general, the minimum transmission unit of data or control information is RB unit. In case of PUCCH, it is mapped to a frequency region corresponding to 1 RB and transmitted for 1 sub-frame.

In the LTE system, an uplink physical channel PUCCH or PUSCH, to which HARQ ACK / NACK corresponding to a PDCCH / EPDDCH including a physical channel for downlink data transmission or a semi-persistent scheduling release (SPS release) Can be defined. For example, in an LTE system operating in a frequency division duplex (FDD), a HARQ ACK / NACK corresponding to a PDCCH / EPDCCH including PDSCH or SPS release transmitted in an n-4th subframe is transmitted in a PUCCH or PUSCH Lt; / RTI &gt;

In the LTE system, the downlink HARQ employs an asynchronous HARQ scheme in which the data retransmission time is not fixed. That is, when HARQ NACK is fed back from the UE to the initial transmission data transmitted from the BS, the BS freely determines the transmission time point of the retransmission data by the scheduling operation. The UE may perform buffering on the data determined to be an error as a result of decoding the received data for HARQ operation, and then perform the combining with the next retransmission data.

The HARQ ACK / NACK information of the PDSCH transmitted in the subframe nk is transmitted from the UE to the Node B through the PUCCH or PUSCH in the subframe n, where k is the FDD or TDD (time division duplex) of the LTE system, May be defined differently depending on the frame setting.

For example, in the case of the FDD LTE system, the k is fixed at 4. Meanwhile, in the TDD LTE system, k may be changed according to the subframe setting and the subframe number. In addition, the value of k may be differently applied according to the TDD setting of each carrier at the time of data transmission through a plurality of carriers. In the case of the TDD, the k value is determined according to the TDD UL / DL setting as shown in [Table 3-2].

[Table 3-2]

Unlike the downlink HARQ in the LTE system, the uplink HARQ adopts a synchronous HARQ scheme in which the data transmission time is fixed. That is, a physical uplink shared channel (PUSCH), a downlink control channel (PDCCH), and a physical hybrid (PHICH) physical channel, in which a downlink HARQ ACK / NACK corresponding to the PUSCH is transmitted, Indicator Channel) can be transmitted and received according to the following rule.

When the UE receives the PDCCH including the uplink scheduling control information transmitted from the base station in the subframe n or the PHICH in which the downlink HARQ ACK / NACK is transmitted, the UE transmits uplink data corresponding to the control information in the subframe n + k PUSCH. Here, k may be defined differently according to the FDD or TDD (time division duplex) of the LTE system and its setting. For example, in the case of an FDD LTE system, k may be fixed to 4. [ Meanwhile, in the TDD LTE system, k may be changed according to the subframe setting and the subframe number. In addition, the value of k may be differently applied according to the TDD setting of each carrier at the time of data transmission through a plurality of carriers. In the case of the TDD, the k value is determined according to the TDD UL / DL setting as shown in [Table 3-3].

[Table 3-3]

On the other hand, the HARQ-ACK information of the PHICH transmitted in the subframe i is related to the PUSCH transmitted in the subframe i-k. For FDD systems, k is given as 4. That is, the HARQ-ACK information of the PHICH transmitted in the subframe i in the FDD system is related to the PUSCH transmitted in the subframe i-4. In case of a TDD system, if a terminal for which Enhanced Interference Mitigation and Traffica Adaptation (EIMTA) is not set is set to only one serving cell or all of them have the same TDD UL / DL setting, the TDD UL / DL setting is 1 to 6 , K value can be given according to the following [Table 3-4].

[Table 3-4]

That is, for example, in the TDD UL / DL setting 1, the PHICH transmitted in the subframe 6 may be the HARQ-ACK information of the PUSCH transmitted in the subframe 2 which is four subframes before.

If the HARQ-ACK is received in the PHICH resource corresponding to I _PHICH = 0 when the TDD UL / DL is set to 0, the PUSCH indicated by the HARQ-ACK information is transmitted from the subframe ik, Table 3-4]. If the HARQ-ACK is received in the PHICH resource corresponding to I _PHICH = 1 when the TDD UL / DL is set to 0, the PUSCH indicated by the HARQ-ACK information is transmitted in the subframe i-6.

The description of the wireless communication system is based on the LTE system, and the contents of the present invention are not limited to the LTE system but can be applied to various wireless communication systems such as NR and 5G. Also, in a case where the present invention is applied to another wireless communication system, the k value may be changed and applied to a system using a modulation scheme corresponding to the FDD.

FIGS. 3C and 3D show data allocated for eMBB, URLLC, and mMTC, which are services to be considered in a 5G or NR system, in frequency-time resources.

Referring to FIGS. 3C and 3D, it is possible to see how frequency and time resources are allocated for information transmission in each system.

In FIG. 3C, data for eMBB, URLLC, and mMTC are allocated in the entire system frequency band 300. if the URLLC data 303, 305 and 307 are generated while the eMBA 301 and the mMTC 309 are allocated and transmitted in a specific frequency band and transmission is required, the eNB 302 and the mMTC 309 are allocated to the eMBB 301 and the mMTC 309 And may transmit the URLLC data 303, 305, 307 without transmitting the eMBB 301 and the mMTC 309.

Since URLLC needs to reduce the delay time, the URLLC data may be allocated (303, 305, 307) to a part of the resource 301 to which the eMBB is allocated. Of course, when URLLC is additionally allocated and transmitted in the resource to which the eMBB is allocated, the eMBB data may not be transmitted in the overlapping frequency-time resources, thereby lowering the transmission performance of the eMBB data. That is, in the above case, eMBB data transmission failure due to URLLC allocation may occur.

In FIG. 3D, the entire system frequency band 400 may be divided into subbands 402, 404, and 406, and used to transmit services and data in the respective subbands 402, 404, and 406. The information related to the subband setting can be predetermined, and the information can be transmitted to the base station through the upper signaling.

Alternatively, information related to the subbands may be provided by the base station or the network node without any separate subband configuration information being transmitted to the terminal. In FIG. 3D, subband 402 is used for eMBB data transmission, subband 404 is used for URLLC data transmission, and subband 406 is used for mMTC data transmission.

The length of the transmission time interval (TTI) used in the URLLC transmission in the first embodiment may be shorter than the TTI length used in the eMBB or mMTC transmission. In addition, the response of the information related to the URLLC can be transmitted faster than the eMBB or mMTC, and thus the information can be transmitted and received with a low delay.

3E is a diagram illustrating a process in which one transport block is divided into a plurality of code blocks and a CRC is added.

3E, a CRC (Cyclic Redundancy Check) 503 may be added to the last or first part of one transport block (TB) 501 to be transmitted in the uplink or the downlink. The CRC may have 16 bits or 24 bits or a predetermined number of bits or a variable number of bits depending on a channel condition or the like and may be used to determine whether channel coding is successful or not.

The blocks 501 and 503 to which the TB and the CRC are added can be divided into a plurality of code blocks 507, 509, 511, and 513 (505). The code block may be divided based on a predetermined maximum size. In this case, the last code block 513 may be smaller than the other code blocks, or may be set to 0, a random value, Can be adjusted to be the same.

CRCs 517, 519, 521, and 523 may be added to the divided code blocks 515, respectively. The CRC may have 16 bits or 24 bits, or a predetermined number of bits, and may be used to determine whether channel coding is successful. However, the CRC 503 added to the TB and the CRCs 517, 519, 521, and 523 added to the code block may be omitted depending on the type of the channel code to be applied to the code block. For example, when low-density parity-check (LDPC) codes are applied to code blocks rather than turbo codes, the CRCs 517, 519, 521, and 523 to be inserted per code block may be omitted. However, even when the LDPC is applied, the CRCs 517, 519, 521, and 523 may be added to the code block as they are. Also, CRC can be added or omitted even when polar codes are used.

FIG. 3F is a diagram illustrating a manner in which an outer code is used and transmitted. FIG. 3G is a block diagram illustrating a structure of a communication system in which the outer code is used.

Referring to FIGS. 3F and 3G, a method of transmitting a signal using an outer code can be described.

In FIG. 3F, one transport block is divided into a plurality of code blocks, and bits or symbols 604 located at the same position in each code block are encoded with a second channel code to generate parity bits or symbols 606 (602). Thereafter, CRCs may be added to the respective code blocks and the parity code blocks generated by the second channel code encoding, respectively (608, 610). The addition of the CRC may vary depending on the type of the channel code. For example, when the turbo code is used as the first channel code, the CRCs 608 and 610 are added, but then each code block and parity code blocks can be encoded with the first channel code encoding.

If an outer code is used, the data to be transmitted passes through a second channel coding encoder 709. The channel code used for the second channel coding may be, for example, a Reed-Solomon code, a Bose-Chaudhuri-Hocquenghem code, a Raptor code, or a parity bit generation code. The bits or symbols that have passed through the second channel coding encoder 709 pass through the first channel coding encoder 711. The channel code used for the first channel coding includes a convolutional code, an LDPC code, a turbo code, and a polar code.

When the channel coded symbols are received by the receiver through the channel 713, the receiver side can sequentially operate the first channel coding decoder 715 and the second channel coding decoder 717 based on the received signal . The first channel coding decoder 715 and the second channel coding decoder 717 may perform operations corresponding to the first channel coding encoder 711 and the second channel coding encoder 709, respectively.

On the other hand, in the channel coding block diagram in which no outer code is used, only the first channel coding encoder 711 and the first channel coding decoder 705 are used in the transceiver, and the second channel coding encoder and the second channel coding decoder are used It does not. Even when the outer code is not used, the first channel coding encoder 711 and the first channel coding decoder 705 can be configured in the same way as in the case where the outer code is used.

The eMBB service described below will be referred to as a first type service and the eMBB data will be referred to as first type data. The first type service or the first type data is not limited to the eMBB, but may be applied to a case where high-speed data transmission is required or a broadband transmission is performed. The URLLC service is referred to as a second type service, and the URLLC data is referred to as second type data. The second type service or second type data is not limited to the URLLC, but may be applicable to other systems requiring low latency or high reliability transmission or requiring low latency and high reliability at the same time.

The mMTC service is called a third type service, and the mMTC data is called a third type data. The third type service or the third type data is not limited to mMTC but may be applied to a case where a low speed, wide coverage, or low power is required. Further, in describing the embodiment, it can be understood that the first type service includes or does not include the third type service.

The structure of the physical layer channel used for each type may be different in order to transmit the three services or data. For example, at least one of a transmission time interval (TTI) length, a frequency resource allocation unit, a control channel structure, and a data mapping method may be different.

Although three services and three pieces of data have been described above, there are more kinds of services and corresponding data. In this case, the contents of the present invention can be applied.

The terms physical channel and signal in a conventional LTE or LTE-A system may be used to describe the method and apparatus proposed in the embodiments. However, the present invention can be applied to wireless communication systems other than LTE and LTE-A systems.

As described above, the embodiment defines transmission and reception operations of a first type, a second type, a third type service, and a terminal and a base station for data transmission, and transmits terminals having different types of services or data scheduling to the same system We suggest a concrete method to operate together. In the present invention, the first type, the second type and the third type terminals are respectively referred to as terminals of type 1, type 2, type 3, or data scheduling. In an embodiment, the first type terminal, the second type terminal and the third type terminal may be the same terminal or may be different terminals.

Hereinafter, at least one of the PHICH, the uplink scheduling grant signal and the downlink data signal is referred to as a first signal. Also, in the present invention, at least one of an uplink data signal for uplink scheduling grant and an HARQ ACK / NACK for a downlink data signal is referred to as a second signal. In an exemplary embodiment, a signal transmitted from a base station to a mobile station may be a first signal if it is a signal expecting a response from the mobile station, and a response signal from a mobile station corresponding to the first signal may be a second signal. Also, in the embodiment, the service type of the first signal may be at least one of eMBB, URLLC, and mMTC, and the second signal may also correspond to at least one of the services.

For example, in LTE and LTE-A systems, PUCCH format 0 or 4 and PHICH may be the first signal, and the corresponding second signal may be PUSCH. For example, in the LTE and LTE-A systems, the PDSCH may be the first signal, and the PUCCH or PUSCH including the HARQ ACK / NACK information of the PDSCH may be the second signal.

In the following embodiments, the TTI length of the first signal may indicate the length of time during which the first signal is transmitted with a time value related to the first signal transmission. Also, in the present invention, the TTI length of the second signal may indicate the length of time that the second signal is transmitted with the time value associated with the second signal transmission, and the TTI length of the third signal may be related to the third signal transmission The time value may indicate the length of time the third signal is transmitted. In the present invention, the second signal transmission timing is information on when the terminal transmits the second signal and when the base station receives the second signal, and may be referred to as a second signal transmission / reception timing.

Also, in the following embodiments, when the BS transmits the first signal in the n-th TTI, and the MS transmits the second signal in the n + k-th TTI, the BS informs the MS of the timing to transmit the second signal Is equivalent to telling k value. Assuming that the base station transmits the first signal in the n-th TTI and the terminal transmits the second signal in the n + 4 + a-th TTI, when the base station informs the terminal of the timing to transmit the second signal, It is like telling the value a. An offset can be defined by various methods such as n + 3 + a and n + 5 + a in place of the n + 4 + a. Hereinafter, the n + 4 + It can be defined.

The contents of the present invention are applicable to FDD and TDD systems.

In the present invention, upper signaling is a signal transmission method that is transmitted from a base station to a base station using a downlink data channel of a physical layer or from a mobile station to a base station using an uplink data channel of a physical layer. A radio resource control (RRC) Signaling, or Packet Data Convergence Protocol (PDCP) signaling, or a MAC (medium access control) MAC control element (MAC CE).

In the present invention, a method of determining the timing of transmitting the second signal after the terminal or the base station receives the first signal has been described. However, the method of sending the second signal can be performed by various methods. For example, the timing of transmitting the HARQ ACK / NACK information corresponding to the PDSCH to the BS after receiving the PDSCH, which is the downlink data, follows the method described in the present invention. However, the timing of selecting the PUCCH format to be used, Or a method of mapping HARQ ACK / NACK information to the PUSCH may be performed according to another method. For example, the selection of the PUCCH format used, the selection of the PUCCH resource, or the mapping of the HARQ ACK / NACK information to the PUSCH may be determined based on the contents of the LTE standard.

In the present invention, a delay reduction terminal, a terminal with delay reduction, a terminal with a reduced processing time, or a terminal with a reduced processing time can be mixed.

[Example 3-1]

The 3-1 embodiment describes a method for determining the timing of the PUSCH transmission when the UE receives the PDCCH / EPDCCH including the PHICH or the DCI for conveying the UL scheduling information. The PHICH may not be used if delay reduction is transmitted to the UE with the delay reduction, and in this case, it may be applied when the DCI which carries the uplink scheduling information is received. In this case, since the HARQ ACK-NACK information for the uplink transmission transmitted with the delay reduction is not received by the PHICH, the UE can omit PHICH decoding in the corresponding subframe.

When the UE receives one of the PDCCH / EPDCCHs including the PHICH or the DCI for transmitting the uplink scheduling information in the subframe n, the PUSCH associated with the PDCCH / EPDCCH is allocated to the subframe n + k , And the k is given by the following [Table 3-5].

[Table 3-5]

When the PDCCH / EPDCCH with the MSB (Most Significant Bit) of the UL index of the UL index of the uplink DCI format is 1 when the TDD UL / DL setting is 0, the PHICH is received by the subframe 1 or 6, When the PHICH is received in the subframe 0 or 5 where the I _PHICH resource is 0, the k value can be determined according to the [Table 3-5]. When the TDD UL / DL setting is 0, PDCCH / EPDCCH with LSB (Least Signigicant Bit) of the UL index of the uplink DCI format is 1, or PHICH is received from subframe 0 or 5 in the place where I _PHICH resource is 1 And the k value can be determined to be 7 when it is received. If both the MSB and the LSB of the UL index of the uplink DCI format are 1, it is possible to transmit the PUSCH in the case of k = 7 and in the subframe n + k when k follows the above [Table 3-5] .

The method when the TDD UL / DL setting is 0 is not only the above method but also a slight modification. For example, when the TDD UL / DL setting is 0, the PDCCH / EPDCCH having the MSB of the UL index of the uplink DCI format is received, the PHICH is received in the subframe 1 or 6, or the PHICH is received in the subframe 0 or 5 When the I _PHICH resource is received at 1, the k value can be determined according to [Table 3-5].

When the PDCCH / EPDCCH with the LSB of the UL index of the uplink DCI format is 1 when the TDD UL / DL setting is 0, or when the PHICH is received with the I _PHICH resource with 0 in the subframe 0 or 5, The value can be determined to be 7. Another example is that when the TDD UL / DL setting is 0, the PDCCH / EPDCCH having the MSB of the UL index of the uplink DCI format is received, the PHICH is received in the subframe 0 or 5, or the PHICH is received in the subframe 1 or 6, when the I _PHICH resource is received at 1, the k value can be determined according to the [Table 3-5].

When the PDCCH / EPDCCH having the LSB of the UL index of the UL index of the uplink DCI format is received when the TDD UL / DL setting is 0, or when the PHICH is received in the subframe 1 or 6 where the I _PHICH resource is 0, The value can be determined to be 6.

[Example 3-2]

The third to second embodiments describe a method for determining a timing of transmitting a PUSCH when a mobile station receives a PDCCH / EPDCCH including a PHICH or a DCI for transmitting uplink scheduling information. The PHICH may not be used if delay reduction is transmitted to the UE with the delay reduction, and in this case, it may be applied when the DCI which carries the uplink scheduling information is received. In this case, since the HARQ ACK-NACK information for the uplink transmission transmitted with the delay reduction is not received by the PHICH, the UE can omit PHICH decoding in the corresponding subframe.

When the UE receives the PHICH or the PDCCH / EPDCCH including the DCI for transmitting the uplink scheduling information in the subframe n, among the values of k greater than 2, when the subframe of n + k is capable of uplink transmission , The UE transmits the PUSCH in the subframe n + k. For example, a UE receiving an uplink DCI in a subframe n transmits a PUSCH in a subframe capable of uplink transmission from n + 3. If n + 3 is the downlink subframe and n + 4 is the uplink transmission, the PUSCH is transmitted in subframe n + 4.

[Example 3-3]

The third to third embodiments describe a method for determining a timing of transmitting a PUSCH when a UE receives a PDCCH / EPDCCH including a PHICH or a DCI for transmitting uplink scheduling information. The PHICH may not be used if delay reduction is transmitted to the UE with the delay reduction, and in this case, it may be applied when the DCI which carries the uplink scheduling information is received. In this case, since the HARQ ACK-NACK information for the uplink transmission transmitted with the delay reduction is not received by the PHICH, the UE can omit PHICH decoding in the corresponding subframe.

When the UE receives one of the PDCCH / EPDCCHs including the PHICH or the DCI for transmitting the uplink scheduling information in the subframe n, the PUSCH associated with the PDCCH / EPDCCH is allocated to the subframe n + k , And the k is given by [Table 3-6].

[Table 3-6]

When the TDD UL / DL setting is 0, the PDCCH / EPDCCH having the MSB of the UL index of the uplink DCI format is received, the PHICH is received in the subframe 0 or 5, or the PHICH is received in the subframe 1 or 6 in the I _PHICH When the resource is received at zero, the k value can be determined according to [Table 3-6].

When the PDCCH / EPDCCH with the LSB of the UL index of the UL index of the uplink DCI format is received when the TDD UL / DL setting is 0, or when the PHICH is received by the I _PHICH resource with 1 at the subframe 1 or 6, The value can be determined to be 3. If the MSB and the LSB of the UL index of the uplink DCI format are both 1, the PUSCH can be transmitted both in the case of k = 3 and in the subframe n + k when k follows the above [Table 3-5] .

The method when the TDD UL / DL setting is 0 is not only the above method but also a slight modification.

[Example 3-4]

The third to fourth embodiments describe a method of determining a timing of PUSCH transmission when a UE receives a PHICH or a PDCCH / EPDCCH including a DCI for conveying uplink scheduling information. The PHICH may not be used if delay reduction is transmitted to the UE with the delay reduction, and in this case, it may be applied when the DCI which carries the uplink scheduling information is received. In this case, since the HARQ ACK-NACK information for the uplink transmission transmitted with the delay reduction is not received by the PHICH, the UE can omit PHICH decoding in the corresponding subframe.

When the UE receives the PHICH or the PDCCH / EPDCCH including the DCI for transmitting the uplink scheduling information in the subframe n, when k is a subframe in which n + k subframes are capable of uplink transmission, , The UE transmits the PUSCH in the subframe n + k. For example, a UE receiving an uplink DCI in a subframe n transmits a PUSCH in a subframe capable of uplink transmission from n + 2. If n + 2 is the downlink subframe and n + 3 is the uplink transmission, the PUSCH is transmitted in the subframe n + 3.

The 3-1 embodiment and the 3-3 embodiment may be used depending on the base station setting to the terminal or may be used according to the information transmitted from the DCI. In addition, the third to eighth embodiments and the third to fourth embodiments may be used according to the base station setting to the terminal, or may be used according to the information transmitted from the DCI. Also, in the above-described embodiments 3-1 to 3-4, the BS may attempt PUSCH decoding in a subframe in which the UE transmits the PUSCH.

FIG. 3h illustrates the operation of the terminal. When the UE receives the PHICH or the PDCCH / EPDCCH including the UL scheduling information, the UE checks at least one of the upper signaling setting, the PHICH resource location, and the DCI information (804). In FIG. 3H, the first timing setting 806 uses the PUSCH transmission timing in the conventional LTE / LTE-A, and may indicate a case where the minimum signal processing time of the terminal is about 3 ms including the TA value . Therefore, if the UE confirms the first timing setting 806, it is equal to the PUSCH transmission timing in the conventional LTE / LTE-A. For example, in the FDD, if UL scheduling information is received in the PDCCH in the subframe n, The PUSCH is transmitted in the frame n + 4 (808).

In FIG. 3h, the second timing setting 810 may indicate a case where the minimum signal processing time of the terminal is about 2 ms including the TA value. Accordingly, when the UE confirms the second timing setting 810, the UE determines timing according to the third or the third embodiment. For example, in FDD, the uplink scheduling information is transmitted from the subframe n to the PDCCH If received, the PUSCH is transmitted in subframe n + 3 (812).

In FIG. 3H, the third timing setting 814 may indicate a case where the minimum signal processing time of the terminal is about 1 ms including the TA value. Accordingly, when the UE confirms the third timing setting 814, it determines the timing according to the 3-3 embodiment or the 3-4 embodiment. For example, in the FDD, the uplink scheduling information is transmitted from the subframe n to the PDCCH If received, the PUSCH is transmitted in subframe n + 2 (816). It is also possible to support only one of the second timing setting 810 and the third timing setting 814 according to the terminal or the base station.

Further, it is also possible that the above-mentioned Embodiment 3-1 and Embodiment 3-3 are combined. For example, when the UE receives a DCI that the uplink scheduling information is transmitted by the PDCCH / EPDCCH, the transmission timing of the PUSCH is determined as in Example 3-1, and the UE receives the PHICH, May be determined as in the third to third embodiments. That is, when the uplink scheduling is performed in the subframe n using the DCI, if the UE transmits the PUSCH to the subframe n + 3 or thereafter and instructs the uplink retransmission using the PHICH, +2 or later, the PUSCH can be transmitted.

In the third to seventh embodiments to the third to fourth embodiments, PHICH denotes information corresponding to HARQ NACK for uplink transmission. Therefore, the reception of the PHICH can be interpreted to mean that the mobile station needs retransmission.

[Example 3-5]

The third to fifth embodiments describe a method for determining a timing for a UE to receive downlink data PDSCH transmission and to transmit an HARQ ACK / NACK for the PDSCH to an uplink channel such as a PUCCH or a PUSCH.

The HARQ ACK / NACK information of the PDSCH transmitted in the subframe n-k is transmitted in the subframe n, and the k may be changed according to the TDD UL / DL setting and the subframe position as shown in Table 3-7 below. In the present embodiment, the PDSCH may be a PDSCH scheduled by a PDCCH / EPDCCH or a PDSCH configured by an SPS.

[Table 3-7]

The order of the numbers written in each column of the table may be modified and applied differently.

In Table 3-7, when there are a plurality of k values, it means that HARQ ACK / NACK information for one or more PDSCHs can be transmitted together in subframe n. For example, HARQ ACK / NACK information corresponding to the PDSCHs transmitted in the UL / DL configuration 1 and before 6 subframes before and 3 subframes in the subframe 2 is transmitted.

[Table 3-7] above can be modified and used as shown in [Table 3-7a].

[Table 3-7a]

The order of the numbers written in each column of the table may be modified and applied differently.

[Example 3-6]

The third to sixth embodiments describe a method for determining a timing for a UE to receive downlink data PDSCH transmission and transmit HARQ ACK / NACK for the PDSCH to an uplink channel such as a PUCCH or a PUSCH.

If the base station transmits the PDSCH to the UE in the subframe n, the UE transmits the HARQ ACK / NACK information related to the PDSCH in a case where k is greater than 2, and the subframe of n + k is uplink- , And the UE transmits in the PUCCH or PUSCH in the subframe n + k. For example, a UE receiving a PDSCH in a subframe n transmits HARQ ACK / NACK information for the PDSCH to a base station in a PUCCH or a PUSCH in a subframe capable of uplink transmission from n + 3. If n + 3 is a downlink subframe and n + 4 is capable of uplink transmission, HARQ ACK / NACK information is transmitted from the subframe n + 4 to the PUCCH or PUSCH.

[Example 3-7]

The third to seventh embodiments describe a method for determining a timing for a UE to receive downlink data PDSCH transmission and to transmit an HARQ ACK / NACK for the PDSCH to an uplink channel such as a PUCCH or a PUSCH.

The HARQ ACK / NACK information of the PDSCH transmitted in the subframe n-k is transmitted in the subframe n, and the k may be changed according to the TDD UL / DL setting and the subframe location as shown in Table 3-8 below. In the present embodiment, the PDSCH may be a PDSCH scheduled by a PDCCH / EPDCCH or a PDSCH configured by an SPS.

[Table 3-8]

The order of the numbers written in each column of the table may be modified and applied differently.

In Table 3-8, when there are a plurality of k values, it means that HARQ ACK / NACK information for one or more PDSCHs can be transmitted together in subframe n. For example, HARQ ACK / NACK information corresponding to PDSCHs transmitted before 3 subframes before 2 subframes in UL / DL configuration 1 and in subframe 2 is transmitted.

[Table 3-8] can be modified and used in the following [Table 3-8a].

[Table 3-8a]

The order of the numbers written in each column of the table may be modified and applied differently.

[Example 3-8]

The third to eighth embodiments describe a method for determining a timing for a UE to receive downlink data PDSCH transmission and transmit HARQ ACK / NACK for the PDSCH to an uplink channel such as a PUCCH or a PUSCH.

If the base station transmits the PDSCH to the UE in the subframe n, the UE transmits the HARQ ACK / NACK information related to the PDSCH to a subframe in which n + k subframes are available for uplink transmission, , And the UE transmits in the PUCCH or PUSCH in the subframe n + k. For example, a UE receiving a PDSCH in a subframe n transmits HARQ ACK / NACK information for the PDSCH to a base station in a PUCCH or a PUSCH in a subframe capable of uplink transmission from n + 2. If n + 2 is a downlink subframe and n + 3 is available for uplink transmission, HARQ ACK / NACK information is transmitted from the subframe n + 3 to the PUCCH or PUSCH.

The third to fifth embodiments and the third to seventh embodiments may be used depending on the base station setting to the terminal or may be used according to the information to be transmitted in the DCI. In addition, the third to sixth embodiments and the third to eighth embodiments may be used according to the base station setting to the terminal, or may be used according to the information to be transmitted in the DCI. In the 3-5th to the 3-8th embodiments, the Node B may attempt to perform PUCCH or PUSCH decoding in a subframe in which the UE transmits PUCCH or PUSCH including HARQ ACK / NACK information for the PDSCH There will be.

3I illustrates the operation of the terminal. When the UE receives the PDSCH, the UE checks at least one of higher signaling setting, DCI information, and the like (903). The first timing setting 905 in FIG. 3I uses HARQ ACK / NACK information transmission timing with the PUCCH or PUSCH in the conventional LTE / LTE-A, and the minimum signal processing time of the terminal is about 3ms Quot; and &quot; when &quot; Therefore, if the UE confirms the first timing setting 905, it is equal to the HARQ ACK / NACK information transmission timing in the conventional LTE / LTE-A. For example, if the PDSCH is received in the subframe n in the FDD, n + 4 transmits HARQ ACK / NACK information through PUCCH or PUSCH (907).

The second timing setting 909 in FIG. 3I may indicate a case where the minimum signal processing time of the terminal is about 2 ms including the TA value. Therefore, if the UE confirms the second timing setting 909, it determines the timing according to the 3-5th embodiment or the 3-6th embodiment. For example, in the FDD, if the PDSCH is received in the subframe n, n + 3 transmits HARQ ACK / NACK information through the PUCCH or PUSCH (911).

The third timing setting 913 in FIG. 3I may indicate a case where the minimum signal processing time of the terminal is about 1 ms including the TA value. Therefore, if the UE confirms the third timing setting 913, it determines the timing according to the 3-7 embodiment or the 3-8 embodiment. For example, in the FDD, if the PDSCH is received in the subframe n, n + 2 transmits HARQ ACK / NACK information through the PUCCH or PUSCH (915). It may be possible to support only one of the second timing setting 909 and the third timing setting 913 depending on the terminal or the base station.

[Example 3-9]

The third to ninth embodiments describe timing at which the terminal controls the power used for uplink transmission.

A UE that can not simultaneously transmit PUCCH and PUSCH can calculate power P _{PUSCH, c} (i) used for PUSCH transmission to be transmitted in subframe i in a specific serving cell c as follows.

A UE capable of simultaneously transmitting PUCCH and PUSCH can calculate power P _{PUSCH, c} (i) used for PUSCH transmission to be transmitted in subframe i in a specific serving cell c as follows.

는 P_CMAX,c(i)의 선형 변화된 값이며,

는 PUCCH 전송 전력인 P_PUCCH(i)의 선형변화된 값이다. M_PUSCH,c(i)는 서빙셀 c에서 서브프레임 i에 PUSCH 전송에 사용하도록 할당된 PRB 수이다.

는 상위 시그널링으로 전달된 파라미터들로 만들어지는 값이다. α_c는

값들 중에 하나로 상위에서 전달될 수 있다. P_Lc는 하향링크 패스로스(pathloss) 추정값으로 단말이 계산할 수 있다. In the above equations, P _{CMAX, c} (i) is the set power that the UE can transmit in sub-frame i in serving cell c.

Is a linearly changed value of P _{CMAX, c} (i)

Is a linearly changed value of P _PUCCH (i) which is the PUCCH transmission power. M _{PUSCH, c} (i) is the number of PRBs allocated for use in PUSCH transmission in subframe i in serving cell c.

Is a value made up of the parameters passed in the upper signaling. α _c is

It can be passed on from one of the values. P _Lc can be calculated by the UE as a downlink pathloss estimation value.

는 PUSCH에서 전송되는 제어신호 부분에 따라 결정될 수 있는 값이다. δ_PUSCH.c는 PDCCH 또는 EPDCCH의 DCI 포맷 0/4 혹은 DCI 포맷 3/3A에 포함된 TPC(Transmission Power Control) 명령에 따라 설정될 수 있는 값이며, 이는 하기와 같은 수식에 따라 적용될 수 있다. 누적 전력 계산이 가능하도록 설정된다면

, 누적 설정이 되어있지 않다면

와 같이 계산한다.

Is a value that can be determined according to the control signal portion transmitted from the PUSCH. ? _PUSCH.c is a value that can be set according to the TPC (Transmission Power Control) command included in the DCI format 0/4 or DCI format 3 / 3A of the PDCCH or EPDCCH, which can be applied according to the following equation. If it is set to enable cumulative power calculation

, And if the cumulative setting is not made

.

The K _PUSCH for determining the timing in the above can be delivered to the upper signaling. For example, if the minimum signal processing time is 1 ms and the delay reduction terminal is set, the terminal can assume that the K _PUSCH is 2. In the above, K _PUSCH is 2 means that the power of the PUSCH to be transmitted in subframe i is determined according to the power control command transmitted in i-2.

Alternatively, an indicator indicating the K _PUSCH value may be included in the DCI format in which the power control command is transmitted. For example, K _PUSCH is 2 when the indicator is 0, and K _PUSCH is 3 when the indicator is 1. The information of the K _PUSCH value indicated by the indicator of the DCI format may be mapped in various ways.

Although the above example is based on the FDD system, the values indicated in the TDD may be provided in the following Table 3-9.

[Table 3-9]

In the TDD UL / DL set 16 will have a K _PUSCH may be determined in accordance with the sub-frame i based on the above table. In the case of the TDD UL / DL setting 0, the method of determining the K _PUSCH value may vary according to the embodiments 3-1 to 3-4.

For example, when the TDD UL / DL setting is 0 in the embodiment 3-1, the PDCCH / EPDCCH having the MSB of 1 in the UL index of the uplink DCI format is received, the PHICH is received in the subframe 1 or 6, When the PHICH is received in the subframe 0 or 5 where the I _PHICH resource is 0, the k value can be determined according to the [Table 3-5]. In addition, when the PDCCH / EPDCCH having the UL index of the UL index of the uplink DCI format is 1, or when the PHICH is received in the subframe 0 or 5 with the I _PHICH resource of 1, the k value can be determined to be 7. Also, when both the MSB and the LSB of the UL index of the uplink DCI format are 1, the method of transmitting the PUSCH in all of the subframe n + k when k is 7 and k is according to Table 3-5 _{Lt; /} RTI &gt; may be determined as follows.

In one example of the 3-1 embodiment, the DCI information for scheduling the PUSCH that can be transmitted in the subframe 3 or 8 may be transmitted in the subframe 0 or 5 of the frame, 0 &lt; / RTI &gt; Therefore, it is necessary to specify in which subframe the PUSCH that can be transmitted in subframe 3 or 8 is scheduled for power control.

In this example, if i is subframe 3 or 8, i.e., if the PUSCH transmission is transmitted in subframe 3 or 8, the LSB of the UL index portion of the DCI format 0 or 4 or other DCI format provided on the PDCCH or EPDCCH is If it is 1, it can be judged to be 7.

[Example 3-10]

The third to tenth embodiments describe at which timing the PHICH including the HARQ-ACK information following the PUSCH transmission is transmitted. Or, it may be described when the PHICH including the HARQ-ACK information received by the UE is associated with the transmitted PUSCH.

The UE with delay reduction can determine that the HARQ-ACK information of the PHICH transmitted in the subframe i is associated with the PUSCH transmitted in the subframe i-k. For FDD systems, k is given as 3. That is, the HARQ-ACK information of the PHICH transmitted in the subframe i in the FDD system is related to the PUSCH transmitted in the subframe i-3. In case of the TDD system, if a terminal with no EIMTA set has only one serving cell or all of them have the same TDD UL / DL setting, when the TDD UL / DL setting is 1 to 6, K &lt; / RTI &gt;

[Table 3-10]

That is, for example, in the TDD UL / DL setting 1, the PHICH transmitted in the subframe 6 may be the HARQ-ACK information of the PUSCH transmitted in the subframe 2 which is four subframes before.

If the HARQ-ACK is received in the PHICH resource corresponding to I _PHICH = 0 when the TDD UL / DL is set to 0, the PUSCH indicated by the HARQ-ACK information is transmitted from the subframe ik, Table 3-4]. If the HARQ-ACK is received in the PHICH resource corresponding to I _PHICH = 1 when the TDD UL / DL is set to 0, the PUSCH indicated by the HARQ-ACK information is transmitted in the subframe i-6. The above method will be used as a method of applying to the delay reduction terminal capable of n + 3.

Alternatively, it may be modified as follows.

The UE with delay reduction can determine that the HARQ-ACK information of the PHICH transmitted in the subframe i is associated with the PUSCH transmitted in the subframe i-k. For FDD systems, k is given as 2. That is, the HARQ-ACK information of the PHICH transmitted in the subframe i in the FDD system is related to the PUSCH transmitted in the subframe i-2. In case of the TDD system, if a terminal with no EIMTA set has only one serving cell or has all the same TDD UL / DL settings, when the TDD UL / DL setting is 1 to 6, K &lt; / RTI &gt;

[Table 3-11]

That is, for example, in the TDD UL / DL setting 1, the PHICH transmitted in the subframe 6 may be the HARQ-ACK information of the PUSCH transmitted in the subframe 3 which is three subframes before.

If the HARQ-ACK is received in the PHICH resource corresponding to I _PHICH = 0 when the TDD UL / DL is set to 0, the PUSCH indicated by the HARQ-ACK information is transmitted from the subframe ik, 4. If the HARQ-ACK is received in the PHICH resource corresponding to I _PHICH = 1 when the TDD UL / DL is set to 0, the PUSCH indicated by the HARQ-ACK information is transmitted in the subframe i-3.

The operation methods corresponding to [Table 3-10] and [Table 3-11] can be selectively operated according to the upper signaling from the base station.

When referring to a subframe i-k or n-k in the present invention, when i-k or n-k is smaller than 0, the subframe i-k or n-k may mean a subframe 10 + i-k or 10 + n-k of the previous radio frame.

The third to tenth embodiments are set and used as in the third to third embodiments, the third to eighth embodiments, the third to third embodiments, and the third to fourth embodiments, And can be used to reduce the retransmission delay time.

[Example 3-11]

In the third to eleventh embodiments, a method for determining a timing of receiving a downlink data PDSCH and transmitting the HARQ ACK / NACK for the PDSCH to an uplink channel such as a PUCCH or a PUSCH will be described. This embodiment can be applied in the case of carrier aggregation, particularly when the Pcell (Primary cell) is the TDD system and the Scell (Secondary cell) is the FDD. The FDD may correspond to a frame structure 1 of LTE, and the TDD may correspond to a frame structure 2 of LTE.

The HARQ ACK / NACK information of the PDSCH transmitted in the subframe n-k is transmitted in the subframe n, and the k may be changed according to the TDD UL / DL setting and the subframe location as shown in Table 3-12 below. In the present embodiment, the PDSCH may be a PDSCH scheduled by a PDCCH / EPDCCH or a PDSCH configured by an SPS.

[Table 3-12]

The order of the numbers written in each column of the table may be modified and applied differently.

In Table 3-12, when there are a plurality of k values, it means that HARQ ACK / NACK information for one or more PDSCHs can be transmitted together in a subframe n.

[Table 3-13] or [Table 3-14] below may be applied instead of using the above [Table 3-12].

[Table 3-13]

[Table 3-14]

[Table 3-13] can be applied for the purpose of minimizing the delay time, and [Table 3-14] can allow the number of HARQ-ACK bits transmitted in one subframe to be maintained in a similar manner. The UL-DL configuration 6 can be applied in combination with the reference UL-DL configuration in the [Table 3-13] and [Table 3-14]. [Table 3-15] and [Table 3-16 And can be applied in a modified manner.

[Table 3-15]

[Table 3-16]

In order to perform the above-described embodiments of the present invention, the transmitter, receiver and processing unit of the terminal and the base station are shown in FIGS. 3J and 3K, respectively. In order to determine the transmission and reception timing of the second signal and the terminal transmission power from the third to the eleventh embodiments to the third to ninth embodiments and to perform the operation according to the transmission and reception timing, The receiving unit, the processing unit, and the transmitting unit of the terminal must operate according to the embodiment, respectively.

3J is a block diagram showing an internal structure of a terminal according to an embodiment of the present invention. As shown in FIG. 3J, the terminal of the present invention may include a terminal receiving unit 1200, a terminal transmitting unit 1204, and a terminal processing unit 1202. The terminal receiving unit 1200 and the terminal may be collectively referred to as a transmitting unit 1204 in the embodiment of the present invention.

The transmitter / receiver of the terminal can transmit / receive signals to / from the base station. The signal may include control information and data. To this end, the transmitting and receiving unit of the terminal may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency.

The transceiver of the terminal may receive the signal through the wireless channel, output the signal to the terminal processor 1202, and transmit the signal output from the terminal processor 1202 through the wireless channel. The terminal processing unit 1202 can control a series of processes so that the terminal can operate according to the embodiment of the present invention described above. For example, the terminal reception unit 1200 receives a signal including the second signal transmission timing information from the base station, and the terminal processing unit 1202 can control to interpret the second signal transmission timing. Thereafter, the terminal transmitter 1204 transmits the second signal according to the above timing.

3K is a block diagram illustrating an internal structure of a base station according to an embodiment of the present invention. As shown in FIG. 3K, the base station of the present invention may include a base station receiving unit 1301, a base station transmitting unit 1305, and a base station processing unit 1303. The base station receiving unit 1301 and the base station transmitting unit 1305 may collectively be referred to as a transmitting and receiving unit in the embodiment of the present invention.

The transmitting and receiving unit of the base station can transmit and receive signals to and from the terminal. The signal may include control information and data. To this end, the base transceiver unit may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency of the received signal.

In addition, the base transceiver unit can receive a signal through a wireless channel, output it to the base station processing unit 1303, and transmit the signal output from the terminal processing unit 1303 through a wireless channel. The base station processing unit 1303 can control a series of processes so that the base station can operate according to the above-described embodiment of the present invention. For example, the base station processor 1303 may determine the second signal transmission timing and control to generate the second signal transmission timing information to be transmitted to the terminal. Then, the base station transmitting unit 1305 transmits the timing information to the terminal, and the base station receiving unit 1301 receives the second signal based on the timing.

Also, according to an embodiment of the present invention, the base station processor 1303 may control to generate downlink control information (DCI) including the second signal transmission timing information. In this case, the DCI may indicate the second signal transmission timing information.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate the understanding of the present invention and are not intended to limit the scope of the present invention. That is, it will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible. Further, each of the above embodiments can be combined with each other as needed. For example, the base station and the terminal can be operated by combining the embodiments 3-1, 3-2, and 3-3 of the present invention with each other. Also, although the above embodiments are presented on the basis of the LTE / LTE-A system, other systems based on the technical idea of the above embodiment may be applicable to other systems such as 5G and NR systems.

Claims (15)

A base station method in a wireless communication system,
Determining control information including at least one of symbol position information and symbol number information on a time axis on which a demodulation reference signal (DMRS) is transmitted;
Transmitting the control information to a terminal; And
And transmitting the DMRS corresponding to the determined control information to the UE. The method according to claim 1,
Wherein the symbol position information on the time axis includes information on a maximum size of a control channel region set in a transmission unit or information on a starting point of a data channel region. The method according to claim 1,
The number of symbol numbers is one or two,
Wherein when the number of symbols is two, the two symbols are continuous to each other. The method according to claim 1,
Wherein the control information is included in an RRC (Radio Resource Control) message or a DCI (Downlink Control Information) message. The method according to claim 1,
Wherein rate matching is performed on the same symbol among the DMRSs for the first UE when it is determined that the DMRS for the first UE and the DMRS for the second UE are transmitted through the same symbol Base station method. A base station of a wireless communication system,
A transmission / reception unit; And
A control unit for determining control information including at least one of symbol position information and symbol number information on a time axis on which a demodulation reference signal (DMRS) is transmitted,
Wherein the control unit transmits the control information to the terminal and controls the transmission / reception unit to transmit the DMRS corresponding to the determined control information to the terminal. The method according to claim 6,
Wherein the symbol position information on the time axis includes information on a maximum size of a control channel region set in a transmission unit or information on a starting point of a data channel region. The method according to claim 6,
The number of symbol numbers is one or two,
Wherein when the number of symbols is two, the two symbols are continuous to each other. The method according to claim 6,
Wherein the control information is included in an RRC (Radio Resource Control) message or a DCI (Downlink Control Information) message. The method according to claim 6,
If the DMRS for the first UE and the DMRS for the second UE are determined to be transmitted through the same symbol, the controller performs rate matching on the same symbol among the DMRS for the first UE . A terminal method in a wireless communication system,
Receiving control information including at least one of symbol position information and symbol number information on a time axis from which a demodulation reference signal (DMRS) is transmitted from a base station; And
And receiving the DMRS corresponding to the determined control information. 12. The method of claim 11,
Wherein the symbol position information on the time axis includes information on a maximum size of a control channel region set in a transmission unit or information on a starting point of a data channel region. 12. The method of claim 11,
The number of symbol numbers is one or two,
Wherein when the number of symbols is two, the two symbols are continuous with each other. In a terminal of a wireless communication system,
A transmission / reception unit for receiving control information including at least one of symbol position information and symbol number information on a time axis on which a demodulation reference signal (DMRS) is transmitted from a base station; And
And a controller for controlling the transceiver to receive the DMRS corresponding to the determined control information. 15. The method of claim 14,
The symbol position information on the time axis includes information on a maximum size of a control channel region set in a transmission unit or information on a start point of a data channel region,
The number of symbol numbers is one or two,
Wherein when the number of symbols is two, the two symbols are continuous with each other.

Images