KR102305472B1 - Method for multiplexing DMRS and data in new radio and Apparatuses thereof - Google Patents

Abstract

The present embodiments provide a method for transmitting and receiving data using empty resource elements (empty REs) located in DMRS symbols in a next-generation/5G radio access network. A method of transmitting to a terminal, comprising the steps of configuring one or more effective resource element patterns, transmitting information indicating an effective resource element pattern usable by the terminal among the effective resource element patterns to the terminal, and DMRS port allocation information to the terminal Including the step of transmitting, the above-described effective resource element pattern is composed of resource elements that are not allocated to the DMRS among the resource elements located on the symbol to which the DMRS can be allocated, through the resource elements in the effective resource element pattern There is provided a method characterized by receiving uplink data from a terminal or transmitting downlink data to the terminal.

Description

Method for multiplexing DMRS and data in a next-generation wireless network and an apparatus therefor

In the present embodiments, a DMRS port is allocated to a terminal in a next-generation/5G radio access network (hereinafter referred to as NR [New Radio] in the present invention) and data using empty resource elements (empty REs) located in the DMRS symbol. Describes how to transmit and receive

3GPP has recently approved "Study on New Radio Access Technology", a study item for research on next-generation/5G radio access technology, and based on this, RAN WG1 has frame structure, channel coding and modulation for NR (New Radio), respectively. , waveforms, and multiple access methods are being discussed. In contrast to LTE/LTE-Advanced, NR is required to be designed to satisfy various needs required for each subdivided and detailed usage scenario as well as an improved data rate compared to LTE/LTE-Advanced.

As representative usage scenarios of NR, eMBB (enhancement Mobile BroadBand), mMTC (massive machine type communication), and URLLC (Ultra Reliable and Low Latency Communications) are proposed, and LTE/LTE-Advanced to satisfy the needs of each usage scenario A flexible frame structure design is required.

In particular, for an empty resource element (empty RE) existing on a symbol in which the DMRS is located in the current NR, data is allocated to an empty resource element (empty RE), and a specific method for signaling data allocation information to the UE is determined. The need is growing.

The purpose of the present embodiments is to allocate a DMRS port and allocate data to empty resource elements (empty REs) located in the DMRS symbol in order to multiplex DMRS and data in the next-generation/5G radio access network. A specific method of allocating data is to provide

An embodiment devised to solve the above problem is a method in which a base station transmits DMRS (Demodulation Reference Signal) port allocation information to a terminal, configuring one or more effective resource element patterns, among the effective resource element patterns The terminal includes the steps of transmitting information indicating an available effective resource element pattern to the terminal and transmitting DMRS port allocation information to the terminal, wherein the above-described effective resource element pattern is located on a symbol to which DMRS can be allocated It is composed of resource elements that are not allocated to DMRS among resource elements, and provides a method characterized by receiving uplink data from a terminal or transmitting downlink data to the terminal through a resource element in an effective resource element pattern. .

In addition, an embodiment provides a method for a terminal to receive DMRS port assignment information from a base station, the method comprising: receiving, from a base station, information indicating an effective resource element pattern usable by the terminal among one or more effective resource element patterns configured by the base station; and receiving DMRS port allocation information from the base station, wherein the above-described effective resource element pattern is composed of resource elements not allocated to DMRS among resource elements located on symbols to which DMRS can be allocated, and effective resources There is provided a method characterized by receiving downlink data from a base station or transmitting uplink data to a base station through a resource element in an element pattern.

In addition, in an embodiment, in a base station transmitting DMRS (Demodulation Reference Signal) port assignment information to a terminal, a control unit constituting one or more effective resource element patterns and an effective resource element pattern usable by the terminal among the effective resource element patterns are indicated. and a transmitter for transmitting information to the terminal and transmitting DMRS port allocation information to the terminal, wherein the above-described effective resource element pattern is a resource element that is not allocated to DMRS among resource elements located on symbols to which DMRS can be allocated. and provides a base station characterized in that it receives uplink data from a terminal or transmits downlink data to the terminal through a resource element in an effective resource element pattern.

In addition, in one embodiment, in a terminal receiving DMRS port allocation information from a base station, information indicating an effective resource element pattern usable by the terminal among one or more effective resource element patterns configured by the base station is received from the base station, and from the base station A receiver for receiving DMRS port allocation information, wherein the above-described effective resource element pattern is composed of resource elements not allocated to DMRS among resource elements located on a symbol to which DMRS can be allocated, and within the effective resource element pattern There is provided a terminal characterized in that it receives downlink data from a base station or transmits uplink data to the base station through a resource element.

According to the present embodiments, in order to multiplex DMRS and data in the next-generation/5G radio access network, a specific method of allocating a DMRS port and allocating data to empty resource elements (empty REs) located in a DMRS symbol can provide

1 is a diagram illustrating the alignment of OFDM symbols in the case of using different subcarrier spacings according to the present embodiments.
2 is a diagram illustrating a downlink (DL) DMRS structure in LTE-A.
3 is a diagram illustrating a 1-symbol DMRS structure configured in a Comb2 + CS scheme.
4 is a diagram illustrating a 2-symbol DMRS structure configured in a Comb2 + CS scheme.
5 is a diagram illustrating a 1-symbol DMRS structure configured in a 2-FD-OCC scheme.
6 is a diagram illustrating a structure of a 2-symbol DMRS configured in a 2-FD-OCC scheme.
7 is a diagram illustrating a pattern of an empty resource element (empty RE) in a Comb + CS scheme.
8 is a diagram illustrating a pattern of an empty resource element (empty RE) in a 2-FD-OCC scheme.
9 is a diagram illustrating an example of a DMRS port allocation and data resource element region in consideration of multi-user pairing (MU pairing).
10 is a diagram illustrating a detailed procedure in which the base station transmits DMRS port allocation information to the terminal in this embodiment.
11 is a diagram illustrating a detailed procedure for the terminal to receive DMRS port allocation information from the base station in this embodiment.
12 is a diagram showing the configuration of a base station according to the present embodiments.
13 is a diagram showing the configuration of a terminal according to the present embodiments.

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

In the present specification, a wireless communication system refers to a system for providing various communication services such as voice and packet data. A wireless communication system includes a user equipment (UE) and a base station (BS).

A user terminal is a comprehensive concept meaning a terminal in wireless communication, and as well as UE (User Equipment) in WCDMA, LTE, HSPA and IMT-2020 (5G or New Radio), etc., MS (Mobile Station) in GSM, UT (User Terminal), SS (Subscriber Station), and should be interpreted as a concept including all of the wireless device (wireless device).

A base station or cell generally refers to a station that communicates with a user terminal, and includes a Node-B (Node-B), an evolved Node-B (eNB), gNode-B (gNB), and a Low Power Node (LPN). ), sector, site, various types of antennas, base transceiver system (BTS), access point, point (eg, transmission point, reception point, transmission/reception point), relay node ( Relay Node), mega cell, macro cell, micro cell, pico cell, femto cell, RRH (Remote Radio Head), RU (Radio Unit), small cell (small cell), etc.

In the various cells listed above, since there is a base station controlling each cell, the base station can be interpreted in two meanings. 1) in relation to the radio area, it may be the device itself providing a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, or a small cell, or 2) may indicate the radio area itself. In 1), the devices providing a predetermined radio area are controlled by the same entity, or all devices interacting to form a radio area cooperatively are directed to the base station. A point, a transmission/reception point, a transmission point, a reception point, etc. become an embodiment of a base station according to a configuration method of a radio area. In 2), the radio area itself in which the signal is received or transmitted from the viewpoint of the user terminal or the neighboring base station may be indicated to the base station.

In the present specification, a cell is a component carrier having a coverage of a signal transmitted from a transmission/reception point or a coverage of a signal transmitted from a transmission/reception point, and the transmission/reception point itself. can

In this specification, the user terminal and the base station are used in an inclusive sense as two (Uplink or Downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by the term or word specifically referred to. does not

Here, the uplink (Uplink, UL, or uplink) refers to a method of transmitting and receiving data by the user terminal to the base station, and the downlink (Downlink, DL, or downlink) is transmitting and receiving data to the user terminal by the base station. means how to

For uplink transmission and downlink transmission, a time division duplex (TDD) scheme transmitted using different times may be used, and a frequency division duplex (FDD) scheme transmitted using different frequencies, a TDD scheme and an FDD scheme may be used. Mixed methods may be used.

In addition, in a wireless communication system, a standard is configured by configuring an uplink and a downlink based on one carrier or a pair of carriers.

The uplink and downlink transmit control information through a control channel such as a Physical Downlink Control CHannel (PDCCH), a Physical Uplink Control CHannel (PUCCH), etc., and a Physical Downlink Shared CHannel (PDSCH), a Physical Uplink Shared CHannel (PUSCH), etc. It consists of the same data channel and transmits data.

A downlink may mean a communication or communication path from a multi-transmission/reception point to a terminal, and an uplink may mean a communication or communication path from the terminal to a multi-transmission/reception point. In this case, in the downlink, the transmitter may be a part of multiple transmission/reception points, and the receiver may be a part of the terminal. Also, in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the multi-transmission/reception point.

Hereinafter, a situation in which signals are transmitted/received through channels such as PUCCH, PUSCH, PDCCH and PDSCH may be expressed in the form of 'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'.

Meanwhile, High Layer Signaling described below includes RRC signaling for transmitting RRC information including RRC parameters.

The base station performs downlink transmission to the terminals. The base station is a physical downlink for transmitting downlink control information such as scheduling required for reception of a downlink data channel, which is a main physical channel for unicast transmission, and scheduling grant information for transmission in an uplink data channel. A control channel may be transmitted. Hereinafter, the transmission and reception of a signal through each channel will be described in the form of transmission and reception of the corresponding channel.

There is no limitation on the multiple access scheme applied in the wireless communication system. Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Non-Orthogonal Multiple Access (NOMA), OFDM-TDMA, OFDM-FDMA, Various multiple access schemes such as OFDM-CDMA can be used. Here, NOMA includes Sparse Code Multiple Access (SCMA) and Low Density Spreading (LDS).

One embodiment of the present invention is asynchronous wireless communication that evolves to LTE/LTE-Advanced, IMT-2020 through GSM, WCDMA, HSPA, and synchronous wireless communication that evolves to CDMA, CDMA-2000 and UMB. can be applied.

In this specification, a machine type communication (MTC) terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. Alternatively, in the present specification, the MTC terminal may mean a terminal defined as a specific category for supporting low cost (or low complexity) and/or coverage enhancement.

In other words, in this specification, the MTC terminal may mean a newly defined 3GPP Release-13 low cost (or low complexity) UE category/type that performs LTE-based MTC-related operations. Alternatively, in this specification, the MTC terminal supports improved coverage compared to the existing LTE coverage, or a UE category/type defined in 3GPP Release-12 or lower that supports low power consumption, or a newly defined Release-13 low cost (or low complexity) UE category/type. Alternatively, it may mean a further Enhanced MTC terminal defined in Release-14.

In the present specification, a NB-IoT (NarrowBand Internet of Things) terminal means a terminal supporting wireless access for cellular IoT. The objectives of NB-IoT technology include improved indoor coverage, support for large-scale, low-speed terminals, low latency sensitivity, ultra-low-cost terminal cost, low power consumption, and optimized network structure.

As a typical usage scenario in NR (New Radio) currently under discussion in 3GPP, eMBB (enhanced Mobile BroadBand), mMTC (massive machine type communication), and URLLC (Ultra Reliable and Low Latency Communication) are being raised.

In the present specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, and various messages related to NR (New Radio) in the present specification can be interpreted in various meanings used in the past or present or used in the future.

[5G NR ]

As a typical usage scenario in NR (New Radio) currently under discussion in 3GPP, eMBB (enhanced Mobile BroadBand), mMTC (massive machine type communication), and URLLC (Ultra Reliable and Low Latency Communication) are being raised.

In the present specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, and various messages related to NR (New Radio) in the present specification can be interpreted in various meanings used in the past or present or used in the future.

3GPP recently approved "Study on New Radio Access Technology", a study item for research on next-generation/5G radio access technology, and based on this, frame structure, channel coding and modulation, waveform and Discussion on multiple access schemes (frame structure, channel coding & modulation, waveform & multiple access scheme) has begun.

NR is required to be designed to satisfy various requirements required for not only an improved data rate compared to LTE/LTE-Advanced, but also for each segmented and detailed usage scenario. In particular, eMBB (enhancement Mobile BroadBand), mMTC (massive MTC), and URLLC (Ultra Reliable and Low Latency Communications) have been raised as representative usage scenarios of NR, and requirements for each usage scenario As a method to satisfy , a flexible frame structure design compared to LTE/LTE-Advanced is required.

Since each usage scenario has different requirements for data rates, latency, coverage, etc., each use through a frequency band constituting an arbitrary NR system Efficient multiplexing of radio resource units based on different numerology (eg subcarrier spacing, subframe, TTI, etc.) as a method for efficiently satisfying requirements for each usage scenario The need for a method for multiplexing is being raised.

As a method for this, for numerology with different subcarrier spacing (SCS) values, TDM, FDM or TDM / FDM based multiplexing and support through one NR carrier (carrier) Methods and methods for supporting one or more time units in configuring a scheduling unit in a time domain have been discussed. In this regard, in NR, a subframe is defined as a type of time domain structure, and reference numerology for defining the subframe duration is used. It was decided to define a single subframe duration consisting of 14 OFDM symbols of the same 15kHz Sub-Carrier Spacing (SCS)-based normal CP overhead as LTE. Accordingly, in NR, a subframe has a duration of 1 ms.

However, unlike LTE, a subframe of NR is an absolute reference time duration, and a slot and a mini-slot as a time unit that is the basis of actual up/downlink data scheduling. ) can be defined. In this case, the number of OFDM symbols constituting the corresponding slot, the y value, was determined to have a value of y=14 regardless of the number.

Accordingly, any slot may consist of 14 symbols, and all symbols are used for downlink transmission (DL transmission), or all symbols are used for uplink transmission ( UL transmission), or may be used in the form of a downlink portion (DL portion) + (gap) + an uplink portion (UL portion).

In addition, a mini-slot consisting of fewer symbols than the corresponding slot is defined in any numerology (or SCS), and based on this, a short-length time domain scheduling interval for uplink/downlink data transmission/reception (time-domain) is defined. scheduling interval) may be set, or a long time-domain scheduling interval for uplink/downlink data transmission/reception may be configured through slot aggregation.

In particular, in the case of transmission/reception of latency critical data such as URLLC, a 0.5ms (7 symbols) or 1ms (14 symbols) based slot defined in a pneumatology-based frame structure with a small SCS value such as 15kHz Since it may be difficult to satisfy the latency requirement when scheduling is performed in units, a mini-slot composed of fewer OFDM symbols than the corresponding slot is defined and based on this, a corresponding URLLC is defined. It can be defined to perform scheduling for latency critical data such as .

Alternatively, as described above, by multiplexing and supporting numerologies having different SCS values in one NR carrier in the TDM scheme or the FDM scheme, based on the slot (or mini-slot) length defined for each NR carrier. A method of scheduling data according to a latency requirement is also being considered. For example, when SCS is 60 kHz as shown in FIG. 1, since the symbol length is reduced by about 1/4 compared to the case of SCS 15 kHz, when one slot is configured with 7 OFDM symbols, the corresponding 15 kHz-based slot length is While it becomes 0.5ms, the slot length based on 60kHz is reduced to about 0.125ms.

As such, in NR, by defining different SCS or different TTI lengths, there is a discussion on how to satisfy the requirements of URLLC and eMBB, respectively.

[ NR DMRS ]

In the downlink DMRS (DL DMRS) of the existing LTE-A, a total of 8 antenna ports are defined from ports 7 to 14 to support 8-layer transmission. , can also be referred to as a DMRS port.)

2 shows a DMRS structure to which an orthogonal cover code (OCC) is applied for PDSCH transmission in LTE downlink. Referring to FIG. 2, antenna ports 7, 8, 11 and 13 use DMRS resource elements (RE) indicated by a pattern of ① in FIG. 2, and antenna ports 9, 10, 12, and 14 have a pattern of ②. The indicated DMRS RE may be used.

In this case, OCC is used to maintain orthogonality between antenna ports allocated to the same DMRS REs, and the values are shown in Table 1 below.

The content defined for the downlink DMRS of the current NR is as follows.

● For the DMRS pattern, the UE may be configured as either a front-loaded DMRS configuration type 1 or a front-loaded DMRS configuration type 2 through an upper layer. (A UE is configured by higher layers with DMRS pattern either from the front-loaded DMRS Configuration type 1 or from the front-loaded DMRS Configuration type 2 for DL/UL):

● Configuration type 1:

- One symbol:

Comb 2 + 2 CS, up to 4 ports

- Two symbols:

Comb 2 + 2 CS + TD-OCC ({1 1} and {1 -1}), up to 8 ports (Comb 2 + 2 CS + TD-OCC ({1 1} and {1 -1}), up to 8 ports)

(Note: It should be possible to schedule up to 4 ports without using both {1,1} and { 1,-1}.)

● Configuration type 2:

- One symbol:

2-FD-OCC across adjacent REs in the frequency domain up to 6 ports

- Two symbols:

2-FD-OCC across adjacent REs in the frequency domain + TD-OCC ({1,1} and {1,-1}) of up to 12 ports in the frequency domain OCC (both {1,1} and {1,-1}) up to 12 ports)

(Note: It should be possible to schedule up to 6 ports without using both {1,1} and { 1,-1}.)

● From UE perspective, frequency domain CDMed DMRS ports are QCLed. (From UE perspective, frequency domain CDMed DMRS ports are QCLed.)

● FFS: Whether the front-load DMRS configuration type for a UE for UL and DL can be different or not.

● If there are significant complexity/performance issues involved in the above agreements, down-selection can still be discussed.

For the NR DMRS, a total of two types of DMRS may be supported. The type of DMRS used may be determined through configuration according to the maximum number of DMRS ports, respectively.

● Front-loaded DMRS configuration 1: Comb + CS structure + TD-OCC

● Front-loaded DMRS configuration 2: FD-OCC + TDM/TD-OCC

comb + cycle shift (Comb + CS) based DMRS structure (up to 8 DMRS port support)

In the aforementioned front-loaded DMRS configuration 1, two structures may be defined according to the number of symbols in which the DMRS is transmitted. This can be divided into a 1-symbol DMRS structure as shown in FIG. 3 and a 2-symbol DMRS structure as shown in FIG. 4 .

The 1-symbol DMRS refers to a DMRS composed of one symbol, and the 2-symbol DMRS refers to a DMRS composed of two symbols. Accordingly, a specific DMRS may be located in one or two symbol intervals on a resource block.

As an example, in FIG. 3, the DMRS may be located on a symbol indicated by symbol index 2, and in this case, the symbol indicated by symbol index 2 may be a DMRS symbol, that is, a symbol to which DMRS can be allocated on a resource block. .

As another example, in FIG. 4, DMRS may be located on symbols indicated by symbol indices 2 and 3, and in this case, symbols indicated by symbol indices 2 and 3 are DMRS symbols, that is, symbols to which DMRS can be allocated on resource blocks. this can be

A resource block (RB) is a unit used by a base station to schedule a data channel or a control channel with a terminal, and is configured in the form of a two-dimensional block on a frequency axis and a time axis. Each resource block may be composed of several resource elements (RE), and each resource element may be indicated through a specific symbol index and subcarrier index. Hereinafter, a case in which one resource block consists of 14 OFDM symbols on the time axis and 12 subcarriers on the frequency axis will be described as an example.

In this case, a comb refers to a method in which DMRSs are mapped on a resource block, and means that DMRSs configured to the same DMRS port are mapped to subcarriers having regular intervals. For example, Comb2 sets the difference of subcarrier indexes between DMRSs set to the same DMRS port to be 2 (eg DMRS set to DMRS port 0 is located at subcarrier indices 0,2,4,6,8,10 ), Comb4 means setting the difference between subcarrier indices set to the same DMRS port to be 4 (eg DMRS set to DMRS port 0 is located at subcarrier indices 0, 4, and 8).

3 is a diagram illustrating a 1-symbol DMRS structure configured in a Comb2 + CS scheme.

First, looking at the Comb2 + 2CS structure as shown in FIG. 3 , a total of two regions may exist for each subcarrier. Here, the region indicated by the pattern ① and the region indicated by the pattern ② are divided, and two cyclic shift values are applied to each region, thereby generating a total of four orthogonal ports.

4 is a diagram illustrating a 2-symbol DMRS structure configured in a Comb2 + CS scheme.

Referring to FIG. 4, a 2-symbol DMRS structure is shown in FIG. 4, and a pattern repeating the case of the 1-symbol DMRS structure may be used as the basic structure. However, the difference from the 1-symbol DMRS structure is in which method is applied for spreading in the time domain.

For example, in the case of TD-OCC={(1,1)}, it is a simple repeating structure, and the number of supported DMRS ports does not increase. However, in TD-OCC={(1,1),(1,-1)}, since two additional orthogonal codes are used, the maximum number of DMRS ports that can be supported can be doubled.

FD - OCC pattern based DMRS structure (up to 12 DMRS port support)

Even in the aforementioned front-loaded DMRS configuration 2, two modes may be defined according to the number of symbols in which the DMRS is transmitted. This can be divided into a 1-symbol DMRS as shown in FIG. 5 and a 2-symbol DMRS structure as shown in FIG. 6 .

5 is a diagram illustrating a 1-symbol DMRS structure configured in a 2-FD-OCC scheme.

First, looking at the structure of 2-FD-OCC up to 6 ports (2-FD-OCC up to 6 ports) of up to 6 ports as shown in FIG. 5, two consecutive subcarriers are adjacent to each other in the frequency domain and allocated to one DMRS. it can be seen that That is, the DMRS may be located in two subcarrier intervals instead of being located in one subcarrier interval as shown in FIGS. 3 and 4 .

In this case, since 2-FD-OCC basically uses OCC of length-2 (={(1,1),(1,-1)}), total It can support two DMRS ports. Accordingly, in FIG. 5, since there are three regions indicated by a total of ①, ②, and ③ patterns, a total of six DMRS ports can be supported.

6 is a diagram illustrating a structure of a 2-symbol DMRS configured in a 2-FD-OCC scheme.

Next, FIG. 6 shows a 2-symbol DMRS structure. It can be seen that the basic structure is based on a 1-symbol DMRS pattern, but TD-OCC is applied to support up to 12 ports.

For example, in TD-OCC={(1,1),(1,-1)}, since two additional orthogonal codes are used, there are 6 ports per symbol for a total of 2 symbols, 6*2 = 12 It can be seen that the port can be supported.

Hereinafter, various embodiments of a method of multiplexing data and DMRS in a DMRS symbol according to the two DMRS configurations described above will be described in detail.

When DMRS ports are not all allocated to all resource elements (REs) existing on a DMRS symbol, that is, a symbol in which DMRS exists, the remaining resource elements (REs) become empty resource elements (empty REs). Accordingly, various approaches to a method of additionally allocating data to such an empty resource element (empty RE) are being discussed.

In the embodiments described below, a method for indicating the location and number of available resource elements (available REs) that can be used for data transmission using only a minimum information field will be described.

The embodiments described below may be applied to both a front-loaded DMRS symbol region and an additional DMRS symbol region.

The embodiments described below may be applied individually or in any combination.

Example One. DMRS Only the number of possible patterns of the empty resource element (empty RE) excluding to the terminal instruction

In general, in order to multiplex DMRS and data, a method of basically instructing the UE with information on DMRS port configuration is being considered. In this case, considering MU-MIMO, not only the DMRS port used by the UE, but also DMRS port configuration information for multi-user pairing UEs (MU pairing UEs) sharing the same time period resource and frequency resource should also be transmitted.

In this way, in order to transmit DMRS port configuration information for multi-user pairing UEs as well, a lot of signaling overhead may occur, and since it violates the basic concept of MU-MIMO, transparent pairing, the specification of Changes can be very demanding.

In this case, being transparent means that each UE does not need to know or consider whether it operates in SU-MIMO or MU-MIMO.

Therefore, in this embodiment, when considering the multi-user pairing situation of the terminal, if the DMRS port allocation information is directly indicated, the size of the DMRS indication information becomes too large, and the above-described transparent pairing is violated. .

Therefore, in this embodiment, it is proposed that the base station transmits only information on an available RE region to each terminal.

The available resource element (available RE) area basically means resource elements to which DMRS is not allocated in the DMRS symbol. And the pattern for the effective resource element means bundled information about the corresponding effective resource element. At this time, according to the DMRS configuration described above, the structure of the pattern for the effective resource element may be different from each other.

Such an effective resource element pattern may also be referred to as a DMRS Code Division Multiplexing (CDM) group, and is not limited by terms or words.

In the following embodiment, a method of first defining a pattern of an available resource element (available RE) before transmitting information on the available resource element (available RE) to the terminal will be described.

Example 1-1. DMRS In configuration 1 (Comb+CS) DMRS All other resource elements (RE) except for the resource element (RE) are composed of one data allocation pattern.

In this embodiment, as shown in FIG. 7 , a method of defining a pattern of an available RE region in DMRS configuration 1 (Comb + CS) is presented. Hereinafter, a method of defining a pattern of an available RE region based on a Comb2 structure will be described as an example. (However, the same method may be applied to Comb4)

For example, suppose that the DMRS port index is defined as 0,1,2,3,4,5,6,7 (total 8 orthogonal ports). (At this time, the specific value of the corresponding index may be changed to another value. can.)

Assuming that the UE is assigned DMRS port 0, DMRS mapping (area indicated by the pattern of ①) as shown in FIG. 7(a) may be performed. In this case, since two cyclic shifts may be applied to the same DMRS resource element RE, DMRS ports 0 and 1 may be allocated as a result.

In this case, the UE may receive an indication of DMRS port allocation information for itself through the downlink DCI (DL DCI) of the PDCCH. At this time, only one entire pattern of available resource elements (available REs) may exist in both the case of FIG. 7(a) and the case of FIG. 7(b).

Therefore, even if the available resource element (available RE) pattern uses only 1-bit information, whether data is transmitted to the empty RE area on the available RE pattern may be indicated to the terminal.

That is, the following information may be included in the field of DCI indicating DMRS port allocation information to the terminal.

● DMRS port indication field (DMRS port indication field): DMRS port assignment information for the terminal

● Valid resource element pattern indication field (Available RE pattern indication field): information indicating whether data is mapped to an empty resource element (empty RE) existing in the DMRS symbol

Here, the UE may interpret as follows according to the 1-bit information value allocated to the Available RE pattern indication field.

● '0': data is not transmitted through an empty resource element (empty RE)

● '1': Data is transmitted through an empty resource element (empty RE)

In this case, the UE operates based on the above-described effective resource element pattern indication field regardless of whether MU-MIMO pairing is performed in its own time interval resource and frequency resource domain. Therefore, the base station, if the DMRS port of another terminal in the DMRS symbol of the terminal is mapped to an empty resource element (empty RE), the effective resource element pattern indication field (Available RE pattern indication field) set to '0' to the terminal Mapping information of the correct data resource element (data RE) can be delivered to

Additionally, since the length of the available RE pattern indication field, that is, the number of bits may vary according to the DMRS configuration described above, the available RE pattern indication field determined according to the DMRS configuration. ) can be unified with the bit value of the larger number among the number of bits.

That is, if the number of bits of the available RE pattern indication field in DMRS configuration 2 (2-FD-OCC) is 2 bits, the effective resource element pattern indication field in DMRS configuration 1 (Comb + CS) ( The number of bits of the Available RE pattern indication field) can be unified to 2 bits. This can be applied in the same way even when the above-mentioned number of bits becomes 3 bits, 4 bits, 5 bits and more.

Example 1-2. DMRS configuration 2(2- FD - OCC ) in their own DMRS All resource elements (RE) except for the resource element (DMRS RE) are composed of two groups of data allocation patterns

In this embodiment, as shown in FIG. 8, a method for DMRS configuration 2 (2-FD-OCC) is presented.

For example, suppose that the DMRS port index is defined as 0,1,2,3,4,5,6,7,8,9,10,11 (total 12 orthogonal ports). Specific values can be changed to other values.)

If it is assumed that the UE is assigned DMRS port 0, DMRS mapping (area indicated by the pattern of ①) as shown in FIG. 8(a) is performed. In this case, since OCC of length-2 may be applied to the same DMRS resource element (RE), DMRS ports 0 and 1 may be allocated as a result.

At this time, as in the embodiment 1-1, the UE may receive an indication of DMRS port assignment information for itself through the downlink DCI (DL DCI) of the PDCCH. In this case, the entire pattern of available resource elements (available REs) may exist up to two in any case as in (a), (b), (c) of FIG. 8 . Therefore, the pattern indicating the available resource element (available RE) requires 2 bits or more, and through this, it is possible to express whether data is transmitted to the empty resource element (empty RE) area on the available resource element (available RE) pattern. .

That is, the following contents may be included in the DCI field.

That is, the following information may be included in the field of DCI indicating DMRS port allocation information to the terminal as in Example 1-1.

● DMRS port indication field (DMRS port indication field): DMRS port assignment information for the terminal

● Valid resource element pattern indication field (Available RE pattern indication field): information indicating whether data is mapped to an empty resource element (empty RE) existing in the DMRS symbol

Here, the UE may interpret as follows according to the 2-bit information value allocated to the Available RE pattern indication field.

● '00': data is not transmitted through an empty resource element (empty RE)

● '01': Data is transmitted through the empty resource element (empty RE) on the available RE pattern 1

● '10': Data is transmitted through an empty RE on the available RE pattern 2

● '11': Data is transmitted through the empty resource element (empty RE) on the available resource element pattern 1 (Available RE pattern 1) and the available resource element pattern 2 (Available RE pattern 2)

In this case, the UE operates based on the above-described effective resource element pattern indication field regardless of whether MU-MIMO pairing is performed in its own time interval resource and frequency resource domain. Therefore, the base station, if the DMRS port of another terminal in the DMRS symbol of the terminal is mapped to an empty resource element (empty RE), using the available RE pattern indication field (Available RE pattern indication field) to the terminal of the other terminal The DMRS port may instruct the UE to exclude the mapped area from data transmission.

For example, as shown in (b) of FIG. 8, it is assumed that the terminal is allocated a DMRS port for the area indicated by the pattern of ②.

At this time, if another terminal is assigned a DMRS port to a resource element on the available resource element pattern 1 by MU-MIMO pairing, the available resource element pattern indication field delivered to the terminal (Available RE pattern indication field) ) = '10', and the UE can know that data is mapped only to resource elements on the available RE pattern 2 (Available RE pattern 2).

Additionally, in this embodiment, the available RE pattern may be relatively determined according to the location of the DMRS resource element (RE) allocated to the UE.

For example, even in the same available RE pattern 1, positions indicating the available resource elements may be different as shown in (a) to (c) of FIG. 8 . In the case of (a) of FIG. 8, the effective resource element pattern 1 (Available RE pattern 1) indicates the RE on the subcarrier index (4,5, 10, 11), and in the case of FIG. 8 (b), the subcarrier RE on index (0,1,6,7) may be indicated, and in the case of FIG. 8(c), RE on subcarrier index (2,3,8,9) may be indicated.

Example 1-3. MU- MIMO pairing When this occurs, the base station DMRS Allocating data for the remaining empty resource elements (empty REs) excluding resource elements Priority After selection, to the terminals Delivers data allocation indication information

MU-MIMO pairing should be basically transparent. Therefore, the UE should not be able to know whether it is in the current MU-MIMO situation.

Therefore, in this embodiment, whether data is allocated to a resource element (RE) in a DMRS symbol regardless of MU-MIMO pairing is defined as a specific pattern, and only information on whether data is mapped to a corresponding resource element (RE) is valid It is proposed to transmit the resource element pattern indication field (Available RE pattern indication field).

At this time, in this embodiment, it is assumed that the base station and two or more terminals form MU-MIMO pairing.

For example, as shown in FIG. 9 , a scenario in which two terminals of a base station, a terminal (UE) #1, and a terminal (UE) #2 form MU-MIMO pairing may be assumed.

In this case, the DMRS allocated to the two terminals UE#1 and UE#2 may be multiplexed using an orthogonal cover code (OCC) on the same DMRS resource element (RE) as shown in FIG. , may be allocated to different DMRS resource elements (REs) as shown in FIG. 9 (b). At this time, one of the following four options can be applied to map data to the remaining available resource elements (available REs) to which the DMRS port is not allocated. can be decided differently.

● Option 1: Allocate all empty resource elements (empty REs) to a specific UE

For example, in FIG. 9(a), all empty resource elements on an available RE pattern are allotted to one of UE#1 or UE#2.

● Option 2: Allocate some of the empty resource elements (empty RE) to a specific UE

For example, in FIG. 9 (a), an empty resource element for one of the available RE pattern 1 or 2 is allocated only to UE#1.

● Option 3: Allocate empty resource elements (empty RE) equally to MU-MIMO paired terminals

For example, in FIG. 9(a), an empty resource element for one available RE pattern is allocated to UE#1 and UE#2, respectively.

● Option 4: Allocate empty resource elements (empty REs) alternately in units of slots

For example, in slot index #N (N is an arbitrary integer), all empty resource elements on an available RE pattern are allocated to UE#1, and in slot index #(N+1), UE#2 is Allocate all empty resource elements on the available RE pattern

Example 1-4. DMRS symbol Defined or changed the allocation pattern or position of my empty resource elements (empty RE) on a specific slot (s) or subframe (s) basis

The aforementioned NR DMRS may set various DMRS patterns in units of 1-symbol and 2-symbol. In this case, in order to map data to empty resource elements (empty REs) in addition to the DMRS resource elements (REs) in the DMRS symbol, the above-described embodiments 1-1 to 1-3 may be used.

At this time, an available RE pattern was defined to map data to empty REs. At this time, the value of the index indicating the available RE pattern is a specific value. It can be defined or changed as a criterion.

That is, in a specific slot index #N (N is an arbitrary integer) in the same time interval and frequency interval position, an effective resource element pattern 1 (available RE pattern 1) may be used, and in the slot index #(N+1), an effective resource element Pattern 2 (available RE pattern 2) may be used. As such, a value that can be used as a reference value for indicating an available RE pattern is as follows.

● Subframe/Slot Index

● Symbol index

● Cell ID

● Antenna port

10 is a diagram illustrating a detailed procedure for the base station to transmit DMRS port allocation information to the terminal in this embodiment.

Referring to FIG. 10, first, the base station may configure one or more effective resource element patterns (S1000).

In this case, the above-described effective resource element pattern may be composed of resource elements not allocated to DMRS among resource elements located on DMRS symbols, ie, symbols to which DMRS can be allocated in a resource block. The base station may transmit/receive data to/from the terminal, ie, receive uplink data from the terminal, or transmit downlink data to the terminal by using all or part of the resource elements constituting the corresponding effective resource element pattern.

Also, the base station may transmit information indicating an effective resource element pattern usable to the terminal among the one or more effective resource element patterns configured in step S1000 to the terminal (S1010). In this case, the information indicating the effective resource element pattern usable by the above-described terminal may be transmitted to the terminal through downlink control information (DCI).

And when the base station transmits information indicating an effective resource element pattern usable by the terminal to the terminal, the indication information is a field indicating antenna port information instead of using a separate independent field in the aforementioned downlink control information. may be included in and transmitted to the terminal.

In addition, information indicating the effective resource element patterns usable by the terminal may include information indicating the number of effective resource element patterns usable by the terminal. For example, the number of effective resource element patterns usable by the terminal may be 1, 2, or 3, and the terminal can determine which effective resource element pattern can be used based on the number information (eg, if 1, the first effective resource element pattern, if it is 2, the first effective resource element pattern and the second effective resource element pattern, if it is 3, the first effective resource element pattern, the second effective resource element pattern, and the third effective resource element pattern) can be known.

In addition, the base station may include the step of transmitting the DMRS port allocation information to the aforementioned terminal (S1020).

11 is a diagram illustrating a detailed procedure for the terminal to receive DMRS port allocation information from the base station in this embodiment.

Referring to FIG. 11 , first, the terminal may receive information indicating an effective resource element pattern usable by the terminal from the base station ( S1100 ).

In this case, the above-described effective resource element pattern may be composed of resource elements not allocated to DMRS among resource elements located on DMRS symbols, ie, symbols to which DMRS can be allocated in a resource block. The terminal may transmit/receive data to/from the base station, ie, receive downlink data from the base station or transmit uplink data to the base station, by using all or part of the resource elements constituting the corresponding effective resource element pattern.

In this case, the information indicating the effective resource element pattern usable by the aforementioned terminal may be received through downlink control information (DCI).

At this time, when the terminal receives information indicating a usable effective resource element pattern from the base station, the corresponding indication information uses the antenna port information instead of using a separate independent field in the aforementioned downlink control information. It may be included in the indicated field and received from the base station.

In addition, information indicating the effective resource element patterns usable by the terminal may include information indicating the number of effective resource element patterns usable by the terminal. For example, the number of effective resource element patterns usable by the terminal may be 1, 2, or 3, and the terminal can determine which effective resource element pattern can be used based on the number information (eg, if 1, the first effective resource element pattern, if it is 2, the first effective resource element pattern and the second effective resource element pattern, if it is 3, the first effective resource element pattern, the second effective resource element pattern, and the third effective resource element pattern) can be known.

In addition, the terminal may include the step of receiving the DMRS port allocation information from the above-described base station (S1110).

12 is a diagram showing the configuration of a base station according to the present embodiments.

Referring to FIG. 12 , the base station 1200 includes a controller 1210 , a transmitter 1220 , and a receiver 1230 .

The controller 1210 may configure one or more effective resource element patterns.

In this case, the above-described effective resource element pattern may be composed of resource elements not allocated to DMRS among resource elements located on DMRS symbols, ie, symbols to which DMRS can be allocated in a resource block. The base station may transmit/receive data to/from the terminal, ie, receive uplink data from the terminal, or transmit downlink data to the terminal by using all or part of the resource elements constituting the corresponding effective resource element pattern.

The transmitter 1220 and the receiver 1230 are used to transmit/receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

Specifically, the transmitter 1220 may transmit information indicating an effective resource element pattern usable by the terminal among the above-described effective resource element patterns to the terminal, and may transmit DMRS port allocation information to the terminal.

In this case, the information indicating the effective resource element pattern usable by the above-described terminal may be transmitted to the terminal through downlink control information (DCI).

And when the base station transmits information indicating an effective resource element pattern usable by the terminal to the terminal, the indication information is a field indicating antenna port information instead of using a separate independent field in the aforementioned downlink control information. may be included in and transmitted to the terminal.

In addition, information indicating the effective resource element patterns usable by the terminal may include information indicating the number of effective resource element patterns usable by the terminal. For example, the number of effective resource element patterns usable by the terminal may be 1, 2, or 3, and the terminal can determine which effective resource element pattern can be used based on the number information (eg, if 1, the first effective resource element pattern, if it is 2, the first effective resource element pattern and the second effective resource element pattern, if it is 3, the first effective resource element pattern, the second effective resource element pattern, and the third effective resource element pattern) can be known.

13 is a diagram showing the configuration of a terminal according to the present embodiments.

Referring to FIG. 13 , the terminal 1300 includes a receiver 1310 , a controller 1320 , and a transmitter 1330 .

The receiver 1310 may receive information indicating an effective resource element pattern usable by the terminal from the base station, and may receive DMRS port assignment information from the base station.

In this case, the above-described effective resource element pattern may be composed of resource elements not allocated to DMRS among resource elements located on DMRS symbols, ie, symbols to which DMRS can be allocated in a resource block. The terminal may transmit/receive data to/from the base station, ie, receive downlink data from the base station or transmit uplink data to the base station, by using all or part of the resource elements constituting the corresponding effective resource element pattern.

In this case, the information indicating the effective resource element pattern usable by the aforementioned terminal may be received through downlink control information (DCI).

At this time, when the terminal receives information indicating a usable effective resource element pattern from the base station, the corresponding indication information uses the antenna port information instead of using a separate independent field in the aforementioned downlink control information. It may be included in the indicated field and received from the base station.

In addition, information indicating the effective resource element patterns usable by the terminal may include information indicating the number of effective resource element patterns usable by the terminal. For example, the number of effective resource element patterns usable by the terminal may be 1, 2, or 3, and the terminal can determine which effective resource element pattern can be used based on the number information (eg, if 1, the first effective resource element pattern, if it is 2, the first effective resource element pattern and the second effective resource element pattern, if it is 3, the first effective resource element pattern, the second effective resource element pattern, and the third effective resource element pattern) can be known.

The standard contents or standard documents mentioned in the above-described embodiment are omitted to simplify the description of the specification and constitute a part of the present specification. Accordingly, it should be construed as falling within the scope of the present invention to add the contents of the standard contents and some of the standard documents to the present specification or to be described in the claims.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

Claims (20)

In the method for the base station to transmit DMRS (Demodulation Reference Signal) port assignment information to the terminal,
constructing one or more valid resource element patterns;
transmitting information indicating an effective resource element pattern usable by the terminal among the available resource element patterns to the terminal; and
Comprising the step of transmitting DMRS port allocation information to the terminal,
The effective resource element pattern is,
Consists of resource elements that are not allocated to DMRS among resource elements located on symbols to which DMRS can be allocated,
A method characterized in that receiving uplink data from the terminal or transmitting downlink data to the terminal through a resource element in the effective resource element pattern.
The method of claim 1,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
Method characterized in that it is transmitted to the terminal through downlink control information.
3. The method of claim 2,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
The method according to claim 1, wherein the information is included in a field indicating antenna port information in the downlink control information and transmitted to the terminal.
The method of claim 1,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
Method characterized by including information indicating the number of effective resource element patterns usable by the terminal among the available resource element patterns.
5. The method of claim 4,
The number of effective resource element patterns usable by the terminal among the effective resource element patterns is one, two, or three.
In a method for a terminal to receive DMRS port allocation information from a base station,
receiving, from the base station, information indicating an effective resource element pattern usable by the terminal from among one or more effective resource element patterns configured by the base station; and
Receiving DMRS port assignment information from the base station,
The effective resource element pattern is,
Consists of resource elements that are not allocated to DMRS among resource elements located on symbols to which DMRS can be allocated,
A method characterized in that receiving downlink data from the base station or transmitting uplink data to the base station through a resource element in the effective resource element pattern.
7. The method of claim 6,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
Method characterized in that it is received from the base station through downlink control information.
8. The method of claim 7,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
The method according to claim 1, wherein the information is included in a field indicating antenna port information in the downlink control information and received from the base station.
7. The method of claim 6,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
Method characterized by including information indicating the number of effective resource element patterns usable by the terminal among the available resource element patterns.
10. The method of claim 9,
The number of effective resource element patterns usable by the terminal among the effective resource element patterns is one, two, or three.
In the base station for transmitting DMRS (Demodulation Reference Signal) port allocation information to the terminal,
a control unit configuring one or more effective resource element patterns; and
A transmitter for transmitting information indicating an effective resource element pattern usable by the terminal among the effective resource element patterns to the terminal, and transmitting DMRS port allocation information to the terminal,
The effective resource element pattern is,
Consists of resource elements that are not allocated to DMRS among resource elements located on symbols to which DMRS can be allocated,
A base station, characterized in that receiving uplink data from the terminal or transmitting downlink data to the terminal through a resource element in the effective resource element pattern.
12. The method of claim 11,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
A base station, characterized in that it is transmitted to the terminal through downlink control information.
13. The method of claim 12,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
A base station, characterized in that it is included in a field indicating antenna port information in the downlink control information and transmitted to the terminal.
12. The method of claim 11,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
The base station, characterized in that it includes information indicating the number of effective resource element patterns usable by the terminal among the effective resource element patterns.
15. The method of claim 14,
The number of effective resource element patterns usable by the terminal among the effective resource element patterns is one, two, or three base stations.
In the terminal receiving the DMRS from the base station,
A receiving unit for receiving information indicating an effective resource element pattern usable by the terminal among one or more effective resource element patterns configured by the base station from the base station, and receiving DMRS port assignment information from the base station,
The effective resource element pattern is,
Consists of resource elements that are not allocated to DMRS among resource elements located on symbols to which DMRS can be allocated,
A terminal for receiving downlink data from the base station or transmitting uplink data to the base station through a resource element in the effective resource element pattern.
17. The method of claim 16,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
A terminal, characterized in that it is received from the base station through downlink control information.
18. The method of claim 17,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
The terminal is included in a field indicating antenna port information in the downlink control information and is received from the base station.
17. The method of claim 16,
Information indicating an effective resource element pattern usable by the terminal among the available resource element patterns is,
The terminal, characterized in that it includes information indicating the number of available resource element patterns available to the terminal among the available resource element patterns.
20. The method of claim 19,
The number of effective resource element patterns usable by the terminal among the effective resource element patterns is one, two or three.

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