KR20190056515A - Method for indicating dmrs layers, antenna ports, and rate-matching in wireless communication system and apparatus thereof - Google Patents

Abstract

Provided are a method for ordering demodulation reference signal (DMRS) layers, antenna ports, and rate-matching in a wireless communication system, which is capable of reducing signal overhead, and an apparatus thereof. According to the present invention, a method for transmitting a DMRS to a terminal in a wireless communication system comprises the steps of: determining a DMRS configuration type of a DMRS transmitted to a terminal among a plurality of DMRS configuration types; transmitting information about the determined DMRS configuration type to the terminal through high layer signaling; determining a code division multiplexing (CDM) group to be used in accordance with a number of layers of the DMRS transmitted to the terminal in the determined DMRS configuration type, an antenna port number, a number of symbols, and multi-user multiple input multiple output (MU-MIMO) to transmit the determined information to the terminal; and configuring the DMRS in accordance with the determined information to transmit the configured DMRS to the terminal.

Description

TECHNICAL FIELD [0001] The present invention relates to a demodulation reference signal (DMRS) layers, antenna ports, and rate-matching indication methods and apparatuses in a wireless communication system. WIRELESS COMMUNICATION SYSTEM AND APPARATUS THEREOF}

The present invention relates to a method and apparatus for indicating information on demodulation reference signal (DMRS) layers, antenna ports and rate-matching for a new wireless communication system, will be.

The International Telecommunication Union (ITU) has been developing IMT (International Mobile Telecommunication) frameworks and standards, and is currently under discussion for 5G (5G) communication through a program called "IMT for 2020 and beyond" .

In order to meet the requirements of " IMT for 2020 and beyond ", the NR (New Radio) system of the 3rd Generation Partnership Project (3GPP) has a variety of subcarriers in consideration of various scenarios, service requirements, Are discussed in the direction of supporting subcarrier spacing (SCS). In addition, the NR system is designed to overcome a bad channel environment such as high-path-loss, phase-noise, and frequency offset occurring on a high carrier frequency The transmission of physical signals / channels through a plurality of beams is also considered. However, according to various SCSs supported by the NR system, a method of constructing a reference signal by considering transmission through a plurality of beams, and transmitting and receiving the reference signal have not yet been specifically defined.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method and apparatus for efficiently constructing a layer and an antenna port by considering both a Single-User Multiple Input Multiple Output (SU-MIMO) operation and a Multi-User MIMO A DMRS layer, an antenna port, and a rate-matching indication method, and a device therefor.

It is another object of the present invention to provide a DMRS layer, an antenna port, and a rate-matching indication method and apparatus that can prevent erroneous decoding between a DMRS and data.

Another object of the present invention is to provide a DMRS layer, an antenna port, and a rate-matching indication method and apparatus which can reduce signaling overhead.

According to an aspect of the present invention, a method of transmitting a Demodulation Reference Signal (DMRS) to a terminal in a wireless communication system includes determining a DMRS configuration type of a DMRS to be transmitted to a terminal among a plurality of DMRS configuration types, And transmitting the information to the MS through a high layer signaling; determining a CDM to be used according to the number of layers of the DMRS to be transmitted to the MS, the antenna port number, the number of symbols, and the MU- (Code Division Multiplexing) group, transmitting the determined information to the MS, and constructing the DMRS according to the determined information and transmitting the DMRS to the MS.

According to the present invention, layers and corresponding antenna ports can be efficiently configured and instructed in consideration of SU-MIMO and MU-MIMO operations in a DMRS used for demodulating data channels and the like.

 Also, according to the present invention, it is possible to prevent erroneous decoding between the DMRS and the data because it is known through rate-matching information whether the data is multiplexed in the FDM scheme in the symbol to which the DMRS is transmitted.

Also, according to the present invention, when indicating a co-scheduled CDM (Code Division Multiplexing) group for rate-matching, not all CDM groups scheduled together are indicated, but information defined according to a specific rule The signaling overhead can be reduced.

1 is a diagram illustrating a wireless communication system to which the present invention is applied.
FIG. 2 is a diagram illustrating a DMRS pattern when a first DMRS configuration type is applied and one symbol is used for the DMRS.
3 is a diagram illustrating a DMRS pattern when the first DMRS configuration type is applied and two symbols are used for the DMRS.
4 is a diagram illustrating a DMRS pattern when a second DMRS configuration type is applied and one symbol is used for the DMRS.
5 is a diagram illustrating a DMRS pattern when a second DMRS configuration type is applied and two symbols are used for DMRS.
6 is a diagram showing an example of mapping of OCC applied to the present invention.
7 is a diagram illustrating a method for transmitting a downlink DMRS according to an embodiment of the present invention.
8 is a diagram illustrating a method for transmitting an uplink DMRS in an embodiment of the present invention.
9 is a block diagram illustrating a wireless communication system in accordance with an embodiment of the present invention.

Hereinafter, the contents related to the present invention will be described in detail with reference to exemplary drawings and embodiments, together with the contents of the present invention. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments 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 disclosure rather unclear.

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal included in the network.

1 is a diagram illustrating a wireless communication system to which the present invention is applied.

The network structure shown in FIG. 1 may be a network structure of an NR (New Radio) system. Hereinafter, the radio communication system to which the present invention is applied is referred to as an NR system. The NR system may include a network structure that meets the criteria of " IMT (International Mobile Telecommunication) -2020 and beyond " defined by the International Telecommunication Union-Radiocommunication sector (ITU-R).

Referring to FIG. 1, a base station (BS) and a user equipment (UE) 12 in the NR system 10 can transmit and receive data wirelessly.

In the NR system 10, the base station 11 can provide a communication service through a specific frequency band to terminals existing within the coverage of the base station. The coverage served by the base station may also be expressed in terms of a site. A site may include a plurality of areas 15a, 15b, 15c, which may be referred to as sectors. Each of the sectors included in the site can be identified based on different identifiers. Each of the sectors 15a, 15b, and 15c can be interpreted as a partial area covered by the base station 11.

The base station 11 generally refers to a station that communicates with the terminal 12 and includes an evolved NodeB, an eNodeB, a gNodeB, a base transceiver system (BTS), an access point, A base station (Femto eNodeB), a home base station (HeNodeB), a home gNodeB, a relay, a remote radio head (RRH), and the like.

Also, the base station 11 may be referred to as various terms such as a megacell, a macrocell, a microcell, a picocell, a femtocell, etc., depending on the size of coverage provided by the corresponding base station. The cell may be used in terms of the frequency band provided by the base station, the coverage of the base station, or the term indicating the base station.

The terminal 12 may be fixed or mobile and may be a mobile station, a mobile terminal, a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA) , A wireless modem, a handheld device, and the like.

Hereinafter, a downlink refers to a communication or communication path from the base station 11 to the terminal 12, and an uplink refers to a communication or communication path from the terminal 12 to the base station 11 do. In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11.

On the other hand, there is no limitation in the multiple access technique applied to the wireless communication system 10. [ For example, a CDMA (Code Division Multiplexing), a CDMA (Code Division Multiple Access), a TDMA (Time Division Multiple Access), an IFDMA (Interleaved FDMA), a FDMA (Frequency Division Multiple Access), an Orthogonal Frequency Division Multiple Access (OFDMA) Various multiple access schemes such as SC-FDMA, OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA may be used. Also, a time division duplex (TDD) scheme or a frequency division duplex scheme (FDD) scheme using different frequencies may be used for uplink and downlink transmission.

Hereinafter, the numerology considered in the NR system will be described. For the design of a system, the numerical value of a fundamental element or factor that creates a resource grid on the time-frequency domain can be taken. For example, subcarrier spacing (SCS) is 15 kHz (or 7.5 kHz in the case of a MBSFN (Multicast-Broadcast Single-Frequency Network)) as an example of a download of the 3GPP LTE / LTE- . However, the terminology does not mean only limited to SCS, but also includes a CP (Cyclic Prefix) length, a TTI (Transmit Time Interval) length, A number of orthogonal frequency division multiplexing (OFDM) symbols, a duration of one OFDM symbol, and the like. That is, the different memorylesses can be distinguished from each other by having different values in at least one of the SCS, the CP length, the TTI length, the number of OFDM symbols within a predetermined time interval, or the duration of one OFDM symbol.

To meet the requirements of "IMT for 2020 and beyond", the NR system considers a plurality of neighbors for various scenarios, various service requirements, and compatibility with potential new systems. More specifically, with the existing radio communication systems, it is difficult to support a higher frequency band, faster moving speed, lower delay, etc. required by " IMT for 2020 and beyond " It is necessary to define.

For example, the NR system may support applications such as Enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (mMTC) / Ultra Machine Type Communications (uMTC), and URLLC (Ultra-Reliable and Low Latency Communications). In particular, the requirements for the user plane latency for the URLLC or eMBB service are 0.5ms in the uplink and 4ms in both the uplink and downlink, which is a requirement for 3GPP Long Term Evolution (LTE) and LTE- A (LTE-Advanced) system with a 10ms latency requirement.

In order to satisfy various scenarios and various requirements in one NR system, it is required to support various types of neurology. In particular, it is required to support a plurality of SCSs, as opposed to supporting one SCS in an existing LTE / LTE-A system.

To solve the problem that a wide bandwidth in a frequency range or a carrier such as 700 MHz or 2 GHz can not be used in a conventional NR system for a plurality of SCS supporting NR systems, May be determined on the assumption of a wireless communication system operating in a frequency range or carrier such as 6 GHz to 6 GHz or 52 GHz, but the scope of the present disclosure is not limited thereto.

  In the NR system, one radio frame may correspond to 10 ms on the time axis, and one subframe may correspond to 1 ms on the time axis. Also, one slot may correspond to 14 or 7 symbols on the time axis. Accordingly, the number of available slots and symbols according to each possible SCS within 10ms corresponding to one radio frame is summarized in Table 1 below. SCS of 480Khz in Table 1 may not be considered.

SCS Number of slots within 10ms
(14 symbols in one slot) Number of slots within 10ms
(7 symbols in one slot) Number of Symbols in 10ms 15Khz 10 20 140 30Khz 20 40 280 60KHz 40 80 560 120Khz 80 N / A 1120 240Khz 160 N / A 2240 480Khz 320 N / A 4480

One physical resource block (PRB) can be defined as a resource area corresponding to one slot on the time axis and 12 subcarriers on the frequency axis.

In such an NR system, a demodulation reference signal (DMRS) for demodulating a specific physical channel is required. For example, a DMRS for demodulating a physical data channel, a DMRS for demodulating a physical control channel, and the like can be defined in the NR system.

In detail, in the NR system, up to eight layers can be supported for transmission of SU-MIMO (multi-user MIMO), and up to 12 orthogonal Layers can be supported. These layers may be mapped to an antenna port (i.e., a logical antenna) and transmitted over a physical channel. Here, in order to properly demodulate a signal transmitted through each layer or an antenna port of a physical channel, a reference signal (RS) for the corresponding layer or antenna port is required, which may be defined as DMRS.

In the NR system, the number of DMRS orthogonal antenna ports (hereinafter, DMRS antenna ports) may be a maximum of 12. For example, the DMRS antenna port number may be defined as # 0 to # 11.

In MU-MIMO, up to 12 different layers can be supported in all terminals. For example, each layer used by each terminal in the MU-MIMO is allocated to the DMRS antenna port numbers # 0, # 1, # 2, # 3, # 4, # 5, # 6, # 7, # 8, 9, # 10, and # 11. However, the actual DMRS antenna port number may vary depending on the RS antenna port number corresponding to the first antenna port of the DMRS. If the RS antenna port number corresponding to the first RS antenna port of the DMRS is #A, the 12 DMRS antenna port numbers are #A, #A + 1, #A + 2, #A + 3, #A + # A + 5, # A + 6, # A + 7, # A + 8, # A + 9, # A + 10 and # A + 11.

Meanwhile, the DMRS pattern can be classified into the following four types according to which DMRS configuration is used for the uplink and downlink and how many symbols are used for the DMRS.

1. If a first DMRS configuration type based on IFDMA is applied and one symbol is used for DMRS

2. If the first DMRS configuration type based on IFDMA is applied and two symbols are used for DMRS

3. If the second DMRS configuration type based on CDM is applied and one symbol is used for DMRS

4. If the second DMRS configuration type based on CDM is applied and two symbols are used for DMRS

In addition, the maximum number of possible DMRS layers per UE can be defined as follows for SU-MIMO and MU-MIMO, respectively.

In the case of SU-MIMO, if a first DMRS configuration type is applied and one symbol is used for the DMRS, up to four distinct layers may be supported for the terminal. If the first DMRS configuration type is applied and two symbols are used for the DMRS, up to eight distinct layers may be supported for the terminal. Also, if DMRS configuration type 2 is applied and one symbol is used for DMRS, up to six distinct layers can be supported for the terminal. If DMRS configuration type 2 is applied and two symbols are used for DMRS, up to eight distinct layers can be supported for the terminal.

In the case of MU-MIMO, if a first DMRS configuration type is applied and one symbol is used for DMRS, up to two distinct layers may be supported for each terminal. If the first DMRS configuration type is applied and two symbols are used for the DMRS, up to four distinct layers may be supported for each terminal. If DMRS configuration type 2 is applied and one symbol is used for DMRS, up to four distinct layers can be supported for each terminal. Even if DMRS configuration type 2 is applied and two symbols are used for DMRS, up to four distinct layers can be supported for each terminal.

When the maximum number of possible DMRS layers per each terminal is N, each layer is allocated with DMRS antenna port numbers # 0, # 1, # 2, # 3, # 4, # 5, # 6, # 7, # 9, # 10, and # 11.

Hereinafter, the DMRS pattern for the NR system will be described in more detail with reference to the accompanying drawings.

FIG. 2 is a diagram illustrating a DMRS pattern when a first DMRS configuration type is applied and one symbol is used for the DMRS.

2 shows " Comb pattern A " and " Comb pattern B " in one symbol and 12 subcarriers (corresponding to one PRB in the frequency domain). The DMRS pattern shown in FIG. 2 is repeated with a plurality of PRBs as much as a bandwidth allocated for transmission of physical channels (e.g., Physical Downlink Shared Channel (PDSCH), Physical Uplink Shared Channel (PUSCH), etc.) And can be applied to each of the DMRS configuration (Front-loaded DMRS configuration or Additional DMRS configuration) within a slot in time axis. "Comb pattern A" may be defined as a DMRS pattern applied to even-numbered subcarriers, and "Comb pattern B" may be defined as a DMRS pattern applied to odd-numbered subcarriers.

As shown in FIG. 2, a total of six REs (Resource Elements) per comb pattern may be allocated to one symbol in one PRB. In this case, the configuration of the DMRS antenna port may be as shown in Table 2 below.

Comb pattern CS (Cyclic Shift) DMRS antenna port # 0 Comb pattern A CS valueA DMRS antenna port # 1 Comb pattern A CS value B DMRS antenna port # 2 Comb pattern B CS valueA DMRS antenna port # 3 Comb pattern B CS value B

Comb pattern in Table 2 is "Comb pattern A" or "Comb pattern B" shown in FIG. 2, and if CS (Cyclic Shift) is a range of possible values for the DMRS sequence, A " has a value of 0, and " CS value B " has a value of X / 2. For example, in the case of X = 12, the value of "CS value A" may be 0 and the value of "CS value B" may be 6. When X = 2?, The value of "CS value A" is 0 and the value of "CS value B" may be π, but is not limited thereto.

Referring to Table 2, the DMRS antenna port numbers are firstly divided into CS values, and then classified into Comb patterns. Comb pattern A can be applied to DMRS antenna port numbers # 0 and # 1, and Comb pattern B can be applied to DMRS antenna ports # 2 and # 3.

3 is a diagram illustrating a DMRS pattern when the first DMRS configuration type is applied and two symbols are used for the DMRS.

3 shows "Comb pattern A" and "Comb pattern n B" in two symbols and 12 subcarriers (corresponding to one PRB in the frequency domain). The DMRS pattern shown in FIG. 3 can be repeatedly extended by a plurality of PRBs by a bandwidth allocated for transmission of physical channels (e.g., PDSCH, PUSCH, etc.) of each terminal on the frequency axis, (Either a front-loaded DMRS configuration or an additional DMRS configuration).

As shown in FIG. 3, a total of six REs may be allocated to one symbol in one PRB per comb pattern. In this case, the configuration of the DMRS antenna port may be as shown in Table 3 below.

Comb pattern CS (Cyclic Shift) TD-OCC DMRS antenna port # 0 Comb pattern A CS valueA [+1, +1] DMRS antenna port # 1 Comb pattern A CS value B [+1, +1] DMRS antenna port # 2 Comb pattern B CS valueA [+1, +1] DMRS antenna port # 3 Comb pattern B CS value B [+1, +1] DMRS antenna port # 4 Comb pattern A CS valueA [+1, -1] DMRS antenna port # 5 Comb pattern A CS value B [+1, -1] DMRS antenna port # 6 Comb pattern B CS valueA [+1, -1] DMRS antenna port # 7 Comb pattern B CS value B [+1, -1]

The Comb pattern in Table 3 is " Comb pattern A " or " Comb pattern B " shown in FIG. In the case of CS, if the range of possible values for the delay value of the DMRS sequence is 0 to X, then "CS value A" may have a value of 0 and "CS value B" may have a value of X / 2. For example, in the case of X = 12, the value of "CS value A" may be 0 and the value of "CS value B" may be 6. When X = 2?, The value of "CS value A" is 0 and the value of "CS value B" may be π, but is not limited thereto.

  Further, TD-OCC (Time Domain-Orthogonal Cover Code) can be applied to two adjacent REs on the same subcarrier on the time axis within each Comb pattern. The value is [+1, +1] or [+1, -1] for [RE that gives priority on the time axis on the same subcarrier and time axis on the same subcarrier, 1 'or' -1 'may be multiplied by the sequence value of the DMRS sequence that is mapped to the corresponding RE.

Referring to Table 3, the DMRS antenna port number is divided into CS values, followed by Comb patterns, and finally TD-OCCs. Comb pattern A can be applied to DMRS antenna port numbers # 0, # 1, # 4 and # 5 and Comb pattern B can be applied to DMRS antenna port numbers # 2, # 3, # 6 and # 7.

4 is a diagram illustrating a DMRS pattern when a second DMRS configuration type is applied and one symbol is used for the DMRS.

FIG. 4 shows "CDM group A", "CDM group B" and "CDM group C" in one symbol and 12 subcarriers (corresponding to one PRB in the frequency domain). The DMRS pattern shown in FIG. 4 can be repeatedly extended by a plurality of PRBs by a bandwidth allocated for transmission of physical channels (e.g., PDSCH, PUSCH, etc.) of each terminal on the frequency axis, (Either a front-loaded DMRS configuration or an additional DMRS configuration).

As shown in FIG. 4, a total of four REs can be allocated to each symbol in one PRB, for each CDM group. In this case, the configuration of the DMRS antenna port may be as shown in Table 4 below.

CDM group FD-OCC DMRS antenna port # 0 CDM group A [+1, +1] DMRS antenna port # 1 CDM group A [+1, -1] DMRS antenna port # 2 CDM group B [+1, +1] DMRS antenna port # 3 CDM group B [+1, -1] DMRS antenna port # 4 CDM group C [+1, +1] DMRS antenna port # 5 CDM group C [+1, -1]

In Table 4, the CDM group is " CDM group A ", " CDM group B ", or " CDM group C " FD-OCC (Frequency Domain-Orthogonal Cover Code) can be applied to two adjacent REs on the same symbol on the frequency axis, within each CDM group. The value is [+1, +1] or [+1, -1] for [RE on the same symbol on the frequency axis, RE on the same symbol on the frequency axis for the next RE] 1 'or' -1 'may be multiplied by the sequence value of the DMRS sequence that is mapped to the corresponding RE.

Referring to Table 4, the DMRS antenna port numbers are firstly distinguished from FD-OCC, and then divided into CDM groups. The CDM group A can be applied to the DMRS antenna port numbers # 0 and # 1, the CDM group B can be applied to the DMRS antenna port numbers # 2 and # 3, and the CMD group C can be applied to the DMRS antenna port numbers # Can be applied.

5 is a diagram illustrating a DMRS pattern when a second DMRS configuration type is applied and two symbols are used for DMRS.

5 shows "CDM group A", "CDM group B", and "CDM group C" in two symbols and 12 subcarriers (corresponding to one PRB in the frequency domain). The DMRS pattern shown in FIG. 5 can be repeatedly extended by a plurality of PRBs as much as a bandwidth allocated for transmission of a physical channel (e.g., PDSCH, PUSCH, etc.) of each terminal in the frequency domain, (Either a front-loaded DMRS configuration or an additional DMRS configuration) within a slot of < RTI ID = 0.0 > As shown in FIG. 5, a total of four REs can be allocated to each symbol in one PRB for each CDM group. In this case, the configuration of the DMRS antenna port can be as shown in Table 5 below.

CDM group FD-OCC TD-OCC DMRS antenna port # 0 CDM group A [+1, +1] [+1, +1] DMRS antenna port # 1 CDM group A [+1, -1] [+1, +1] DMRS antenna port # 2 CDM group B [+1, +1] [+1, +1] DMRS antenna port # 3 CDM group B [+1, -1] [+1, +1] DMRS antenna port # 4 CDM group C [+1, +1] [+1, +1] DMRS antenna port # 5 CDM group C [+1, -1] [+1, +1] DMRS antenna port # 6 CDM group A [+1, +1] [+1, -1] DMRS antenna port # 7 CDM group A [+1, -1] [+1, -1] DMRS antenna port # 8 CDM group B [+1, +1] [+1, -1] DMRS antenna port # 9 CDM group B [+1, -1] [+1, -1] DMRS antenna port # 10 CDM group C [+1, +1] [+1, -1] DMRS antenna port # 11 CDM group C [+1, -1] [+1, -1]

In Table 5, the CDM group is "CDM group A", "CDM group B", or "CDM group C" shown in FIG. FD-OCC can be applied to two adjacent REs on the same symbol on the frequency axis, within each CDM group. The value is [+1, +1] or [+1, -1] for [RE on the same symbol on the frequency axis, RE on the same symbol on the frequency axis for the next RE] 1 'or' -1 'may be multiplied by the sequence value of the DMRS sequence that is mapped to the corresponding RE. Further, the TD-OCC can be applied to two adjacent REs on a time axis on the same subcarrier. The value is [+1, +1] or [+1, -1] for [RE on the same subcarrier on time axis, RE on the same subcarrier on time axis for next RE] 'Or' -1 'may be multiplied by the sequence value of the DMRS sequence that is mapped to the corresponding RE.

Referring to Table 5, the DMRS antenna port number is divided into FD-OCCs, then CDM groups, and finally TD-OCCs. CDM group A can be applied to DMRS antenna ports # 0, # 1, # 6 and # 7 and CDM group B can be applied to DMRS antenna ports # 2, # 3, # 8 and # DMRS antenna ports # 4, # 5, # 10, # 11.

6 is a diagram showing an example of mapping of OCC applied to the present invention.

6, "TD-OCC" in FIGS. 2 and 3, "FD-OCC" in FIGS. 3 and 4, and "FD-OCC and TD-OCC" Specific examples that are mapped are shown.

Referring to FIG. 6, when the value of the TD-OCC is [+1, +1], the DMRS sequence value mapped to the RE of the lower symbol index for the two REs corresponding to two consecutive symbols on the same subcarrier +1 is multiplied, and the DMRS sequence value mapped to the RE of the next symbol index can be multiplied by +1.

When the value of the TD-OCC is [+1, -1], the DMRS sequence value mapped to the RE of the lower symbol index is multiplied by +1 for two REs corresponding to two consecutive symbols on the same subcarrier, Then the DMRS sequence value mapped to the RE in the next symbol index may be multiplied by -1.

When the value of the FD-OCC is [+1, +1], the DMRS sequence value mapped to the RE of the lower subcarrier index is multiplied by +1 for two REs corresponding to two consecutive subcarriers on the same symbol , Then the DMRS sequence value mapped to the RE in the next subcarrier index may be multiplied by +1.

When the value of the FD-OCC is [+1, -1], the DMRS sequence value mapped to the RE of the lower subcarrier index is multiplied by +1 for two REs corresponding to two consecutive subcarriers on the same symbol , And the DMRS sequence value mapped to the RE of the next subcarrier index may be multiplied by -1.

When both the TD-ODD and the FD-OCC are applied, the OCC value can be multiplied by the time axis and the frequency axis with respect to the REs belonging to the same CDM group according to the above-described method.

Hereinafter, a signaling method for configuring and directing a layer and an antenna port for transmission of a DMRS in consideration of the following factors in a DMRS used for demodulating data channels and the like in an NR system will be described.

In the NR system, the DMRS may consist of a first DMRS configuration type based on IFDMA and a second DMRS configuration type based on CDM.

Each DMRS configuration can be divided into one symbol configuration or two symbol configurations. Therefore, the DMRS configuration is composed of (1) a first DMRS configuration type of one symbol, (2) a first DMRS configuration type of two symbols, (3) a second DMRS configuration type of one symbol, (4) And a second DMRS configuration type.

(1) a first DMRS configuration type of one symbol, (2) a first DMRS configuration type of two symbols, (3) a second DMRS configuration type of one symbol, (4) 8, 6, and 8 layers and their corresponding antenna ports can be distinguished from each other for the second DMRS configuration type of the first DMRS configuration type.

(1) the first DMRS configuration type of one symbol, (2) the first DMRS configuration type of two symbols, (3) the second DMRS configuration type of one symbol, (4) In the MU-MIMO, up to 12 layers and corresponding antenna ports can be allocated to all of the UEs in the MU-MIMO, Can be distinguished from each other.

Also, in the NR system, when designating a CDM group used by a specific terminal for rate-matching, a CDM group used by other terminals (hereinafter referred to as a scheduled CDM group) have. However, instead of instructing the all scheduled CDM groups together to reduce the signaling overhead when instructing the group of the scheduled CDMs together, it may indicate information defined according to a specific rule.

Hereinafter, indicating co-scheduled CDM groups for rate-matching will be described in more detail.

  For each DMRS configuration shown in FIGS. 2 through 5, the RE pattern can be summarized as follows.

If one symbol is used in the first DMRS configuration pattern based on IFDMA, Comb pattern A can be applied to DMRS antenna ports # 0 and # 1, and Comb pattern B can be applied to DMRS antenna ports # 2 and # 3 .

Comb pattern A may be applied to DMRS antenna ports # 0, # 1, # 4, and # 5, Comb pattern B may be applied to DMRS antenna ports # 2, # 3, # 6, # 7.

Comb pattern groups may be composed of antenna ports using the same RE pattern. The antenna ports in the Comb pattern group share the same RE resources and can be divided into CS value and / or FD-OCC. The Comb pattern group can be defined as a CDM group as in the second DMRS configuration type.

When one symbol is used in the second DMRS configuration pattern based on the CDM, the CDM group A can be applied to the DMRS antenna ports # 0 and # 1, and the CDM group B can be applied to the DMRS antenna ports # 2 and # 3 , And the CDM group B can be applied to the DMRS antenna ports # 4 and # 5.

If two symbols are used in the second DMRS configuration pattern based on the CDM, the CDM group A can be applied to the DMRS antenna ports # 0, # 1, # 6 and # 7, the CDM group B can be applied to the DMRS antenna ports # # 3, # 8, # 9, and the CDM group C can be applied to the DMRS antenna ports # 4, # 5, # 10, # 11.

The CDM group may be composed of antenna ports using the same RE pattern. The antenna ports in the CDM group share the same RE resources and can be divided into FD-OCC and / or TD-OCC.

The DMRS and data (NR-PDSCH or NR-PUSCH) can be multiplexed into FDM within the same symbol. However, in a MU-MIMO environment, when a specific terminal transmits a DMRS using an RE pattern corresponding to a first CDM group, the specific terminal may notify the other terminals of the RE pattern corresponding to the remaining CDM groups except for the first CDM group It can not be known whether or not it is used to transmit the DMRS. Therefore, in performing rate matching for data transmission, it is impossible to know whether or not the RE pattern corresponding to the remaining CDM group should be excluded or included. Assuming that the RE pattern corresponding to the remaining CDM group is always excluded from the data transmission, the RE pattern corresponding to the remaining CDM group is also excluded from the data transmission even when the other terminals do not transmit the DMRS, Resulting in performance deterioration. Assuming that the RE pattern corresponding to the remaining CDM group is always included in the data transmission, even if the other terminals transmit the DMRS to the RE pattern corresponding to the remaining CDM group, they are included in data transmission, This can also cause performance degradation. Therefore, in order to solve the above problem, when the BS indicates a CDM group for a DMRS to a specific UE, it may indicate a co-scheduled CDM group used by another UE for rate matching. Table 6 below shows all cases indicating the scheduled CDM group together.

Occation Configuring DMRS CDM group used by a specific terminal A co-scheduled CDM group used by another terminal Case 1 Configuration type 1 Comb pattern A None Case 2 Comb pattern A Comb pattern B Case 3 Comb pattern B None Case 4 Comb pattern B Comb pattern A Case 5 Comb pattern A, B No need for indication Case 6 Configuration type 2 CDM group A None Case 7 CDM group A CDM group B Case 8 CDM group A CDM group C Case 9 CDM group A CDM group B, C Case 10 CDM group B None Case 11 CDM group B CDM group A Case 12 CDM group B CDM group C Case 13 CDM group B CDM group A, C Case 14 CDM group C None Case 15 CDM group C CDM group A Case 16 CDM group C CDM group B Case 17 CDM group C CDM group A, B Case 18 CDM group A, B None Case 19 CDM group A, B CDM group C Case 20 CDM group A, C None Case 21 CDM group A, C CDM group B Case 22 CDM group B, C None Case 23 CDM group B, C CDM group A Case 24 CDM groups A, B, C No need for indication

Considering all cases where the CDM group is scheduled together for rate-matching as shown in Table 6, the signaling overhead becomes worse because the number of cases is too large. Therefore, instead of instructing all cases for a group of CDMs scheduled together to reduce the signaling overhead, only possible cases can be specified and specified only according to certain rules.

The specific rule is, for example, as follows.

1. For the DMRS configuration using one symbol in the first DMRS configuration type, if the total number of antenna ports considered in MU-MIMO is N, if N is '1' or '2', only Comb pattern A is used do. If N is '3' or '4', comb pattern A and comb pattern B are used.

2. In the DMRS configuration using two symbols in the first DMRS configuration type, if the number of total antenna ports considered in MU-MIMO is N, if N is one of '1' to '4' A only. If N is any one of '5' to '8', Comb pattern A and Comb pattern B are used.

3. For the DMRS configuration using one symbol in the second DMRS configuration type, if N is '1' or '2', the total number of antenna ports considered in MU-MIMO is N do. If N is '3' or '4', CDM group A and CDM group B are used. If N is '5' or '6', CDM group A, CDM group B and CDM group C are used.

4. In the case of the DMRS configuration using 2 symbols in the second DMRS configuration type 2, if N is one of '1' to '4' when the total number of antenna ports considered in MU-MIMO is N, Use only Group A. If N is any one of '5' to '8', CDM group A and CDM group B are used. If N is any one of '9' to '12', CDM group A, CDM group B and CDM group C are used.

That is, in the case of the first DMRS configuration type, N antenna ports can be allocated from Comb pattern A to the number N of total antenna ports used for a plurality of terminals in MU-MIMO, and then allocated to Comb pattern B .

In the case of the second DMRS configuration type, N antenna ports are allocated from the CDM group A to the number N of total antenna ports used for a plurality of terminals in MU-MIMO, then allocated to the CDM group B, Can be assigned to the next CDM group C.

Table 7 below shows all cases in which the CDM group scheduled together according to the above specific rules is indicated.

Occation Configuring DMRS CDM group used by a specific terminal A co-scheduled CDM group used by another terminal Case 1 Configuration type 1 Comb pattern A None Case 2 Comb pattern A Comb pattern B Case 3 Comb pattern B Comb pattern A Case 4 Comb pattern A, B No need for indication Case 5 Configuration type 2 CDM group A None Case 6 CDM group A CDM group B Case 7 CDM group A CDM group B, C Case 8 CDM group B CDM group A Case 9 CDM group B CDM group A, C Case 10 CDM group C CDM group A, B Case 11 CDM group A, B None Case 12 CDM group A, B CDM group C Case 13 CDM groups A, B, C No need for indication

Referring to Table 7, if Comb Pattern A is used for a particular UE, there may not be a co-scheduled CDM group used by other UEs (Case 1), and Comb Pattern B may be scheduled together (Case 2) .

Referring to Table 7, when Comb pattern B is used for a specific UE, the total antenna ports used for a plurality of UEs in MU-MIMO are allocated from Comb pattern A and then allocated to Comb pattern B, The scheduled CDM group is always Comb Pattern A (Case 3).

Referring to Table 7, when both the Comb pattern A and the Comb pattern B are used for a specific UE, it is unnecessary to separately designate the CDM group that is scheduled together (Case 4).

Referring to Table 7, if a CDM group A is used for a particular UE, there may not be a co-scheduled CDM group used by another UE (Case 5), a CDM group B may be scheduled together (Case 6) , CDM group B and CDM group C may be scheduled together (Case 7).

Referring to Table 7, if the CDM group B is used for a specific UE, the total antenna ports used for a plurality of UEs in the MU-MIMO are allocated from the CDM group A and then allocated to the next CDM group B, The co-scheduled CDM group used by CDM group A may be CDM group A (Case 8), CDM group A and CDM group C (Case 9).

Referring to Table 7, if CDM group C is used for a specific UE, the total antenna ports used for a plurality of UEs in MU-MIMO are allocated from CDM group A and CDM group B, then allocated to CDM group C , The co-scheduled CDM group used by the other terminals is always CDM group A and CDM group B (Case 10).

Referring to Table 7, if a CDM group A and a CDM group B are used for a specific terminal, there may not be a co-scheduled CDM group used by another terminal (Case 11), and the CDM group C may be scheduled together (Case 12).

 Referring to Table 7, if the CDM group A, the CDM group B, and the CDM group C are all used for a specific terminal, the CDM group used together by other terminals need not be separately instructed (Case 13).

On the other hand, a co-scheduled CDM group used by another UE may be represented by the number of CDM groups scheduled together, which are additionally considered. Therefore, Table 7 can be described in other ways as shown in Table 8 below.

Occation Configuring DMRS The specific terminal uses
CDM Group The number of scheduled CDM groups that are additionally considered together Case 1 Configuration type 1 Comb pattern A 0 Case 2 Comb pattern A 1 (Comb pattern B) Case 3 Comb pattern B 1 (Comb pattern A) Case 4 Comb pattern A, B 0 Case 5 Configuration type 2 CDM group A 0 Case 6 CDM group A 1 (CDM group B) Case 7 CDM group A 2 (CDM group B, C) Case 8 CDM group B 1 (CDM group A) Case 9 CDM group B 2 (CDM group A, C) Case 10 CDM group C 2 (CDM group A, B) Case 11 CDM group A, B 0 Case 12 CDM group A, B 1 (CDM group C) Case 13 CDM groups A, B, C 0

Referring to Table 8, if Comb Pattern A is used for a particular UE in the case of the first DMRS configuration type, the number of the simultaneously scheduled CDM groups to be considered together may be 0 (Case 1) or 1 Case 2, in this case Comb pattern B together scheduling).

Referring to Table 8, if Comb Pattern B is used for a specific UE in the case of the first DMRS configuration type, the total antenna ports used for a plurality of UEs in MU-MIMO are allocated from Comb pattern A, The number of simultaneously scheduled CDM groups considered together is always 1 (Case 3, in which case Comb pattern A is also scheduled together).

Referring to Table 8, if Comb Pattern A and Comb Pattern B are used for a specific UE in the case of the first DMRS configuration type, the number of CDM groups to be scheduled together is always 0 (Case 4).

Referring to Table 8, if the CDM group A is used for a particular UE in the case of the second DMRS configuration type, the number of additional co-scheduled CDM groups may be 0 (Case 5), 1 Case 6, in this case CDM group B together scheduling), 2 (Case 7, in this case CDM group B and CDM group C scheduling together).

Referring to Table 8, if the CDM group B is used for a specific UE in the case of the second DMRS configuration type, the total antenna ports used for a plurality of UEs in the MU-MIMO are allocated from the CDM group A, (Case 8, in this case the scheduling of the CDM group A together), it may be 2 (Case 9, in which case the CDM group A and the CDM Group C together).

Referring to Table 8, if the CDM group C is used for a specific UE in the case of the second DMRS configuration type, the total antenna ports used for a plurality of UEs in the MU-MIMO are allocated from the CDM group A and the CDM group B And then allocated to the CDM group C, the number of scheduling CDM groups that are additionally considered together is always 2 (Case 10, in which case CDM group A and CDM group B together scheduling).

Referring to Table 8, if the CDM group A and the CDM group B are used for a specific UE in the case of the second DMRS configuration type, the number of the CDM groups to be additionally considered together may be 0 (Case 11) (Case 12, in this case CDM group C scheduling together).

Referring to Table 8, if the CDM group A, the CDM group B, and the CDM group C are used for a specific terminal in the case of the second DMRS configuration type, the number of the CDM group to be scheduled together is not zero Case 13).

Hereinafter, an antenna port number configured according to the number of codewords and the number of layers will be described. It is assumed here that a maximum of two code words are used. One codeword (codeword 0) may be used when one to four layers are used for each terminal, two codewords (codeword 0, codeword 1) may be used when five to eight layers are used, Can be used.

If one layer is used in the first DMRS configuration type based on the IFDMA, the codeword 0 is set to any one of the DMRS antenna ports # 0 to # 7 (# 1 or # 2 or # 3 or # 4 or # 5 or # or # 7). In this case, codeword 1 is disabled.

When two layers are used in the first DMRS configuration type, codeword 0 can be used as antenna ports # 0 to # 1 or # 2 to # 3 or # 4 to # 5 or # 6 to # 7. Considering that Comb pattern A is assigned to antenna ports {# 0, # 1} and Comb pattern B is assigned to antenna ports {# 2, # 3} when Comb pattern is composed of one symbol, The DMRS antenna port for the base station may be {# 0, # 1} or {# 2, # 3}. When Comb pattern is composed of two symbols, Comb pattern A is assigned to antenna ports {# 0, # 1, # 4, # 5} DMRS antenna ports for two layers can be assigned to either {# 0, # 1} or {# 4, # 5} or {# 2, # 3} or {# 6, # 7 }. In this case, codeword 1 is not used.

 When three layers are used in the first DMRS configuration type, codeword 0 may be used as antenna ports # 0 to # 2 or # 0 / # 1 / # 4 or # 2 / # 3 / # 6. Considering that Comb pattern A is assigned to antenna ports {# 0, # 1} and Comb pattern B is assigned to antenna ports {# 2, # 3} when Comb pattern is composed of one symbol, , The DMRS antenna port for the mobile station may be {# 0, # 1, # 2}. When Comb pattern is composed of two symbols, Comb pattern A is assigned to antenna ports {# 0, # 1, # 4, # 5} The DMRS antenna port for three layers may be {# 0, # 1, # 4} or {# 2, # 3, # 6}. In this case, codeword 1 is not used.

When four layers are used in the first DMRS configuration type, codeword 0 is transmitted to antenna ports # 0 to # 3 or # 0 / # 1 / # 4 / # 5 or # 2 / # 3 / # 6 / Can be used. Considering that Comb pattern A is assigned to antenna ports {# 0, # 1} and Comb pattern B is assigned to antenna ports {# 2, # 3} when Comb pattern is composed of one symbol, The DMRS antenna port for the mobile station may be {# 0, # 1, # 2, # 3}. When Comb pattern is composed of two symbols, Comb pattern A is assigned to antenna ports {# 0, # 1, # 4, # 5} DMRS antenna ports for three layers may be {# 0, # 1, # 4, # 5} or {# 2, # 3, # 6, # 7} . In this case, codeword 1 is not used.

If five layers are used in the first DMRS configuration type, codeword 0 may be used for antenna ports # 0 to # 1 and codeword 1 may be used for antenna ports # 2 / # 3 / # 6. When Comb pattern is composed of two symbols, Comb pattern A is assigned to antenna ports {# 0, # 1, # 4, # 5} Considering that Comb pattern B is allocated, the DMRS antenna port for five layers may be {# 0, # 1} for codeword 0 and {# 2, # 3, # 6} for codeword 1 . That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to two antenna ports in descending order of the antenna port index of the Comb pattern A, and the antenna ports transmitted through the codeword 1 are the Comb pattern B May be three antenna ports in descending order of the antenna port index.

If six layers are used in the first DMRS configuration type, codeword 0 may be used for antenna ports # 0 / # 1 / # 4 and codeword 1 may be used for antenna ports # 2 / # 3 / # 6. When Comb pattern is composed of two symbols, Comb pattern A is assigned to antenna ports {# 0, # 1, # 4, # 5} DMRS antenna port for six layers is {# 0, # 1, # 4} for codeword 0 and {# 2, # 3, # 6} for codeword 1, Lt; / RTI > That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to three antenna ports in descending order of the antenna port index among the antenna ports corresponding to the Comb pattern A, and the antenna ports transmitted through the codeword 1 are the Comb pattern B May be three antenna ports in descending order of the antenna port index.

If seven layers are used in the first DMRS configuration type, codeword 0 may be used for antenna ports # 0 / # 1 / # 4 and codeword 1 may be used for antenna ports # 2 / # 3 / # 6 / have. When Comb pattern is composed of two symbols, Comb pattern A is assigned to antenna ports {# 0, # 1, # 4, # 5} DMRS antenna port for seven layers is {# 0, # 1, # 4} for codeword 0 and {# 2, # 3, # 6, # 7}. That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to three antenna ports in descending order of the antenna port index among the antenna ports corresponding to the Comb pattern A, and the antenna ports transmitted through the codeword 1 are the Comb pattern B The antenna ports corresponding to four antenna ports in descending order of the antenna port index.

When eight layers are used in the first DMRS configuration type, codeword 0 is used for antenna ports # 0 / # 1 / # 4 / # 5 and codeword 1 is used for antenna ports # 2 / # 3 / # 6 / . When Comb pattern is composed of two symbols, Comb pattern A is assigned to antenna ports {# 0, # 1, # 4, # 5} DMRS antenna port for eight layers is {# 0, # 1, # 4, # 5} for code word 0 and {# 2, # 3, # 6, # 7}. That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to four antenna ports in descending order of the antenna port index of the Comb pattern A, and the antenna ports transmitted through the codeword 1 are the Comb pattern B The antenna ports corresponding to four antenna ports in descending order of the antenna port index.

If one layer is used in the second DMRS configuration type based on the CDM, the codeword 0 is set to any one of the DMRS antenna ports # 0 to # 11 (# 1 or # 2 or # 3 or # 4 or # 5 or # 6 or # 7 or # 8 or # 9 or # 10 or # 11). In this case, codeword 1 is not used.

If two layers are used in the second DMRS configuration type, codeword 0 is assigned to antenna ports # 0 to # 1 or # 2 to # 3 or # 4 to # 5 or # 6 to # 7 or # # 10 to # 11. When the CDM group is composed of one symbol, the CDM group A is allocated to the antenna ports {# 0, # 1}, the CDM group B is allocated to the antenna ports {# 2, # 3} 5, the DMRS antenna port for two layers can be {# 0, # 1} or {# 2, # 3} or {# 4, # 5}. Also, when the CDM group is composed of two symbols, the CDM group A is allocated to the antenna ports {# 0, # 1, # 6, # 7} And the DMRS antenna port for the two layers is {# 0, # 1}, considering that the CDM group B is allocated to the antenna ports {# 4, # 5, # 10, # 11} Or may be {# 6, # 7} or {# 2, # 3} or {# 8, # 9} or {# 4, # 5} or {# 10, # 11}. In this case, codeword 1 is not used.

If three layers are used in the second DMRS configuration type, codeword 0 is assigned to antenna ports # 0 to # 2 or # 3 to # 5 or # 0 / # 1 / # 6 or # 2 / # 3 / # 4 / # 5 / # 10 or # 7 / # 9 / # 11. When the CDM group is composed of one symbol, the CDM group A is allocated to the antenna ports {# 0, # 1}, the CDM group B is allocated to the antenna ports {# 2, # 3} 5, the DMRS antenna port for three layers may be {# 0, # 1, # 2} or {# 3, # 4, # 5}. Also, when the CDM group is composed of two symbols, the CDM group A is allocated to the antenna ports {# 0, # 1, # 6, # 7} And the CDM group C is allocated to the antenna ports {# 4, # 5, # 10, # 11}, the DMRS antenna ports for the three layers are allocated to {# 0, # 1, # 6, or {# 2, # 3, # 8} or {# 4, # 5, # 10} or {# 7, # 9, # 11}. Here, antenna ports {# 7, # 9, # 11} may not be used. In this case, codeword 1 is not used.

If four layers are used in the second DMRS configuration type, codeword 0 is assigned to antenna ports # 0 to # 3 or # 0 / # 1 / # 6 / # 7 or # 2 / # 3 / # 8 / # 4 / # 5 / # 10 / # 11. When the CDM group is composed of one symbol, the CDM group A is allocated to the antenna ports {# 0, # 1}, the CDM group B is allocated to the antenna ports {# 2, # 3} 5}, the DMRS antenna ports for the four layers may be {# 0, # 1, # 2, # 3}. Also, when the CDM group is composed of two symbols, the CDM group A is allocated to the antenna ports {# 0, # 1, # 6, # 7} And the CDM group C is allocated to the antenna ports {# 4, # 5, # 10, # 11}, the DMRS antenna ports for the four layers are assigned to {# 0, # 1, # 6, # 7} or {# 2, # 3, # 8, # 9} or {# 4, # 5, # 10, # 11}. In this case, codeword 1 is not used.

If five layers are used in the second DMRS configuration type, codeword 0 may be used for antenna ports # 0 to # 1 and codeword 1 may be used for antenna ports # 2 to # 4. This corresponds to the case where the CDM group is composed of one symbol, the CDM group A is allocated to the antenna port {# 0, # 1}, the CDM group B is allocated to the antenna port {# 2, # 3} # 4, # 5}, the DMRS antenna port for the five layers may be {# 0, # 1, # 2, # 3, # 4}.

Or 5th layer in the second DMRS configuration type, codeword 0 may be used for antenna ports # 0 to # 1 and codeword 1 may be used for antenna ports # 2 / # 3 / # 8. This corresponds to the case where the CDM group is composed of two symbols, and the CDM group A is assigned to the antenna ports {# 0, # 1, # 6, # 7} # 9}, and the CDM group C is allocated to the antenna ports {# 4, # 5, # 10, # 11}, DMRS antenna ports for five layers are assigned to {# 0, # 1, # 2, # 3, # 8}. That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to two antenna ports in descending order of the antenna port index among the antenna ports corresponding to the CDM group A. The antenna ports transmitted through the codeword 1 are the CDM group B May be three antenna ports in descending order of the antenna port index.

If six layers are used in the second DMRS configuration type, codeword 0 may be used for antenna ports # 0 to # 2, and codeword 1 may be used for antenna ports # 3 to # 5. This corresponds to the case where the CDM group is composed of one symbol, the CDM group A is allocated to the antenna port {# 0, # 1}, the CDM group B is allocated to the antenna port {# 2, # 3} # 4, # 5}, the DMRS antenna port for six layers may be {# 0, # 1, # 2, # 3, # 4, # 5}.

Or 6th layer in the second DMRS configuration type, codeword 0 may be used for antenna ports # 0 / # 1 / # 6 and codeword 1 may be used for antenna ports # 2 / # 3 / # 8. This corresponds to the case where the CDM group is composed of two symbols, and the CDM group A is assigned to the antenna ports {# 0, # 1, # 6, # 7} # 9} and the CDM group C is allocated to the antenna ports {# 4, # 5, # 10, # 11}, the DMRS antenna ports for the six layers are assigned to {# 0, # 1, # 6, # 2, # 3, # 8}. That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to three antenna ports in descending order of the antenna port index among the antenna ports corresponding to the CDM group A. The antenna ports transmitted through the codeword 1 are the CDM group B May be three antenna ports in descending order of the antenna port index.

When seven layers are used in the second DMRS configuration type, codeword 0 is used as antenna port # 0 / # 1 / # 6 and codeword 1 can be used as antenna port # 2 / # 3 / # 8 / have. The CDM group A is allocated to the antenna ports {# 0, # 1, # 6, # 7}, and the antenna ports {# 2, # 3, # 8, # 9}, and the CDM group C is allocated to the antenna ports {# 4, # 5, # 10, # 11}, the DMRS antenna port for the seven layers is {0, # 1, # 6, # 2, # 3, # 8, # 9}. That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to three antenna ports in descending order of the antenna port index among the antenna ports corresponding to the CDM group A. The antenna ports transmitted through the codeword 1 are the CDM group B The antenna ports corresponding to four antenna ports in descending order of the antenna port index.

When eight layers are used in the second DMRS configuration type, codeword 0 is used for antenna ports # 0 / # 1 / # 6 / # 7 and codeword 1 is used for antenna ports # 2 / # 3 / # 8 / . The CDM group A is allocated to the antenna ports {# 0, # 1, # 6, # 7}, and the antenna ports {# 2, # 3, # 8, # 9}, and the CDM group C is allocated to the antenna ports {# 4, # 5, # 10, # 11}, the DMRS antenna ports for the eight layers are assigned to {# 0, # 1, # 6, # 7, # 2, # 3, # 8, # 9}. That is, the antenna ports transmitted through the codeword 0 are antenna ports corresponding to four antenna ports in descending order of the antenna port index among the antenna ports corresponding to the CDM group A. The antenna ports transmitted through the codeword 1 are the CDM group B The antenna ports corresponding to four antenna ports in descending order of the antenna port index.

개에 해당하는 안테나 포트들이며, 코드워드 1을 통해 전송되는 안테나 포트들은 Comb 패턴 B에 해당하는 안테나 포트들 중 안테나 포트 인덱스가 낮은 순으로

개에 해당하는 안테나 포트들일 수 있다.(N = 5, 6, 7, 8) in which a particular terminal transmits N DMRSs using two codewords in the first DMRS configuration type of two of the above cases, one of the two codewords The antenna ports transmitted through codeword 0 and the antenna ports transmitted through codeword 1 are antenna ports belonging to different CDM groups. Specifically, the antenna ports transmitted through the codeword 0 are arranged in descending order of the antenna port index among the antenna ports corresponding to the Comb pattern A

And the antenna ports transmitted through the codeword 1 are the antenna ports corresponding to the Comb pattern B,

Antenna ports.

개에 해당하는 안테나 포트들이며, 코드워드 1을 통해 전송되는 안테나 포트들은 CDM 그룹 B에 해당하는 안테나 포트들 중 안테나 포트 인덱스가 낮은 순으로

개에 해당하는 안테나 포트들일 수 있다.In a case where a specific terminal transmits N DMRSs (N = 5, 6, 7, 8) using two codewords in a second DMRS configuration type of two symbols among the above cases, Antenna ports transmitted through codeword 0 and antenna ports transmitted through codeword 1 are antenna ports belonging to different CDM groups. Specifically, the antenna ports transmitted through the codeword 0 are arranged in descending order of the antenna port indexes of the antenna ports corresponding to the CDM group A

And the antenna ports transmitted through the codeword 1 are the antenna ports corresponding to the CDM group B in descending order of the antenna port index

Antenna ports.

Hereinafter, a method for the BS to configure and direct the information for the DMRS in the NR system will be described.

In a first embodiment, the base station may use the number of DMRS symbols (1 or 2), the number of layers, the antenna port number and the scheduled CDM group The number of scheduled CDM groups) can be indicated as one table. Here, the number of layers and the corresponding antenna port number can be considered as follows.

In SU-MIMO, up to 4 layers can be distinguished for a DMRS configuration of one symbol, and up to 8 layers and an antenna port for a DMRS configuration of two symbols can be distinguished.

- In MU-MIMO, up to 2 layers can be distinguished for a DMRS configuration of one symbol per terminal, and up to 4 layers and an antenna port for a DMRS configuration of 2 symbols.

- In MU-MIMO, up to four DMRS configuration of one symbol and up to eight layers and corresponding antenna port of DMRS configuration of two symbols can be distinguished from all UEs.

Lt; RTI ID = 0.0 > CDM < / RTI > In this case, when the BS indicates the CDM group scheduled for the corresponding MS, the BS does not indicate all the CDM groups scheduled together for the other MSs, but instead indicates the CDM group scheduled according to the rules described in Tables 7 and 8 (Or the number of CDM groups scheduled together).

Here, the table may be included as a signaling field of downlink control information (DCI) for each UE.

If one codeword (codeword 0 is used and codeword 1 is not used), the table is shown in Table 9 below.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number (Number of)
Co-scheduled CDM group (s) 0 One One #0 0 One One One #0 1 (Comb pattern B) 2 One One #One 0 3 One One #One 1 (Comb pattern B) 4 One One #2 1 (Comb pattern A) 5 One One # 3 1 (Comb pattern A) 6 One 2 # 0, # 1 0 7 One 2 # 0, # 1 1 (Comb pattern B) 8 One 2 # 2, # 3 1 (Comb pattern A) 9 One 3 # 0 ~ # 2 0 10 One 4 # 0 ~ # 3 0 11 2 One #0 0 12 2 One #0 1 (Comb pattern B) 13 2 One #One 0 14 2 One #One 1 (Comb pattern B) 15 2 One #2 1 (Comb pattern A) 16 2 One # 3 1 (Comb pattern A) 17 2 One #4 0 18 2 One #4 1 (Comb pattern B) 19 2 One # 5 0 20 2 One # 5 1 (Comb pattern B) 21 2 One # 6 1 (Comb pattern A) 22 2 One # 7 1 (Comb pattern A) 23 2 2 # 0, # 1 0 24 2 2 # 0, # 1 1 (Comb pattern B) 25 2 2 # 2, # 3 1 (Comb pattern A) 26 2 2 # 4, # 5 0 27 2 2 # 4, # 5 1 (Comb pattern B) 28 2 2 # 6, # 7 1 (Comb pattern A) 29 2 3 # 0, # 1, # 4 0 30 2 3 # 0, # 1, # 4 1 (Comb pattern B) 31 2 3 # 2, # 3, # 6 1 (Comb pattern A) 32 2 4 # 0, # 1, # 4, # 5 0 33 2 4 # 0, # 1, # 4, # 5 1 (Comb pattern B) 34 2 4 # 2, # 3, # 6, # 7 1 (Comb pattern A) 35 Reserved ... ... 63 Reserved

The order of the bit values in Table 9 may be reversed, but the messages included in Table 9 are the same, and the specific contents thereof may be in accordance with FIGS. 2 to 6 and Tables 2 to 8.

The DMRS antenna ports corresponding to Comb pattern A and Comb pattern B in Table 9 are as follows.

In the case of the first DMRS configuration type using one symbol, the DMRS antenna ports corresponding to Comb pattern A are # 0 and # 1, and the DMRS antenna ports corresponding to Comb pattern B are # 2 and # 3.

The DMRS antenna ports corresponding to the Comb pattern A are # 0, # 1, # 4 and # 5, and the DMRS antenna ports corresponding to the Comb pattern B are the # 2, # 3, # 6, and # 7.

Here, the Comb pattern group is composed of antenna ports using the same RE pattern. The antenna ports share the same RE resources and can be divided into a CS value and / or an FD-OCC, and can be defined as a CDM group as in the second DMRS configuration type.

On the other hand, if two codewords (codeword 0 and codeword 1 are used) are indicated, the table is shown in Table 10 below.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number (Number of)
Co-scheduled CDM group (s) 0 2 5 # 0, # 1,
# 2, # 3, # 6 0 One 2 6 # 0, # 1, # 4,
# 2, # 3, # 6 0 2 2 7 # 0, # 1, # 4,
# 2, # 3, # 6, # 7 0 3 2 8 # 0, # 1, # 4, # 5,
# 2, # 3, # 6, # 7 0 4 Reserved ... ... 63 Reserved

The order of the bit values in Table 10 may be reversed, but the messages included in Table 10 are the same, and the specific contents thereof may be in accordance with FIGS. 2 to 6 and Tables 2 to 8.

In the case of the first DMRS configuration type based on the IFDMA, the base station transmits the number of the DMRS symbols (one or two), the number of layers, the antenna port number and the scheduled CDM group (or the scheduled CDM group (The first table according to Table 9 and the second table according to Table 10) for each codeword. In this case, the first table has 35 substantial bit values (bit value 0 to bit value 34) except for the "Reserved" bit value. The second table has four practical bit values (bit value 0 to bit value 3) except for the " Reserved " bit value. Each table value can be indicated via a 6-bit signaling field included in the DCI. This is because 6 bits of signaling are required considering the maximum 35 configurations shown in Table 9. [

In the case of the first DMRS configuration type based on the IFDMA, the base station can also determine the number (one or two) of DMRS symbols used for the corresponding terminal, the number of layers, the antenna port number, and the scheduled CDM group Can be indicated as three tables for each symbol and codeword. In this case, the first table may consist of only one symbol in Table 9. [ That is, the first table may include only one symbol configuration when the codeword is one of the configurations of Table 9. In this case, the first table has 11 substantial bit values (bit value 0 to bit value 10) except for the "Reserved" bit value. The second table may consist of only two symbols in Table 9. That is, a second codeword can be included in the second table only in the case of a two-symbol configuration. At this time, the second table has 24 actual bit values (bit value 11 to bit value 34) except for the "Reserved" bit value. The third table may have the configuration shown in Table 10. In this case, the third table has four substantial bit values (bit value 0 to bit value 3) except for the "Reserved" bit value. Each table value can be indicated via a 5-bit signaling field included in the DCI. This is because 5-bit signaling is required considering a maximum of 24 configurations of two symbol configurations in Table 9. [ In this case, it can be indicated through a separate 1-bit signaling field included in the DCI whether the corresponding table is composed of one symbol or two symbols.

In the case of the second DMRS configuration type based on the CDM, the BS also calculates the number (1 or 2) of the DMRS symbols used for the corresponding UE, the number of layers, the antenna port number and the scheduled CDM group Number of groups) can be designated as one table. In this case, the number of layers and the corresponding antenna port number may be considered as follows.

- In SU-MIMO, up to six layers can be distinguished for a DMRS configuration of one symbol, and up to eight layers and corresponding antenna ports for a DMRS configuration of two symbols.

In the MU-MIMO, up to four DMRS configurations of one symbol per terminal and up to four layers of DMRS configuration of two symbols and corresponding antenna ports can be distinguished.

- In MU-MIMO, up to six DMRS configurations of one symbol and up to twelve layers of DMRS configuration of two symbols and corresponding antenna ports can be distinguished from all terminals in the MU-MIMO.

Lt; RTI ID = 0.0 > CDM < / RTI > In this case, when the BS indicates the CDM group scheduled for the corresponding MS, the BS does not indicate all the CDM groups scheduled together for the other MSs, but instead indicates the CDM group scheduled according to the rules described in Tables 7 and 8 (Or the number of CDM groups scheduled together).

Here, the table may be included as a DCI signaling field for each UE.

If one codeword (codeword 0 is used and codeword 1 is not used), the table is as shown in Table 11 below.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number (Number of)
Co-scheduled CDM group (s) 0 One One #0 0 One One One #0 1 (CDM group B) 2 One One #0 2 (CDM group B, C) 3 One One #One 0 4 One One #One 1 (CDM group B) 5 One One #One 2 (CDM group B, C) 6 One One #2 1 (CDM group A) 7 One One #2 2 (CDM group A, C) 8 One One # 3 1 (CDM group A) 9 One One # 3 2 (CDM group A, C) 10 One One #4 2 (CDM group A, B) 11 One One # 5 2 (CDM group A, B) 12 One 2 # 0, # 1 0 13 One 2 # 0, # 1 1 (CDM group B) 14 One 2 # 0, # 1 2 (CDM group B, C) 15 One 2 # 2, # 3 1 (CDM group A) 16 One 2 # 2, # 3 2 (CDM group A, C) 17 One 2 # 4, # 5 2 (CDM group A, B) 18 One 3 # 0, # 1, # 2 0 19 One 3 # 0, # 1, # 2 1 (CDM group C) 20 One 3 # 3, # 4, # 5 1 (CDM group A) 21 One 4 # 0, # 1, # 2, # 3 0 22 One 4 # 0, # 1, # 2, # 3 1 (CDM group C) 23 2 One #0 0 24 2 One #0 1 (CDM group B) 25 2 One #0 2 (CDM group B, C) 26 2 One #One 0 27 2 One #One 1 (CDM group B) 28 2 One #One 2 (CDM group B, C) 29 2 One #2 1 (CDM group A) 30 2 One #2 2 (CDM group A, C) 31 2 One # 3 1 (CDM group A) 32 2 One # 3 2 (CDM group A, C) 33 2 One #4 2 (CDM group A, B) 34 2 One # 5 2 (CDM group A, B) 35 2 One # 6 0 36 2 One # 6 1 (CDM group B) 37 2 One # 6 2 (CDM group B, C) 38 2 One # 7 0 39 2 One # 7 1 (CDM group B) 40 2 One # 7 2 (CDM group B, C) 41 2 One #8 1 (CDM group A) 42 2 One #8 2 (CDM group A, C) 43 2 One # 9 1 (CDM group A) 44 2 One # 9 2 (CDM group A, C) 45 2 One # 10 2 (CDM group A, B) 46 2 One # 11 2 (CDM group A, B) 47 2 2 # 0, # 1 0 48 2 2 # 0, # 1 1 (CDM group B) 49 2 2 # 0, # 1 2 (CDM group B, C) 50 2 2 # 2, # 3 1 (CDM group A) 51 2 2 # 2, # 3 2 (CDM group A, C) 52 2 2 # 4, # 5 2 (CDM group B, C) 53 2 2 # 6, # 7 0 54 2 2 # 6, # 7 1 (CDM group B) 55 2 2 # 6, # 7 2 (CDM group B, C) 56 2 2 # 8, # 9 1 (CDM group A) 57 2 2 # 8, # 9 2 (CDM group A, C) 58 2 2 # 10, # 11 2 (CDM group B, C) 59 2 3 # 0, # 1, # 6 0 60 2 3 # 0, # 1, # 6 1 (CDM group B) 61 2 3 # 0, # 1, # 6 2 (CDM group B, C) 62 2 3 # 2, # 3, # 8 1 (CDM group A) 63 2 3 # 2, # 3, # 8 2 (CDM group A, C) 64 2 3 # 4, # 5, # 10 2 (CDM group A, B) 65 2 3 # 7, # 9, # 11 0 66 2 4 # 0, # 1, # 6, # 7 0 67 2 4 # 0, # 1, # 6, # 7 1 (CDM group B) 68 2 4 # 0, # 1, # 6, # 7 2 (CDM group B, C) 69 2 4 # 2, # 3, # 8, # 9 1 (CDM group A) 70 2 4 # 2, # 3, # 8, # 9 2 (CDM group A, C) 71 2 4 # 4, # 5, # 10, # 11 2 (CDM group A, B) 72 Reserved .... ... 127 Reserved

The order of the bit values in Table 11 can be reversed, but the messages included in Table 11 are the same, and the concrete contents thereof can be followed from FIGS. 2 to 6 and Tables 2 to 8.

In Table 11, the DMRS antenna ports corresponding to CDM group A, CDM group B and CDM group C are as follows.

In the case of the second DMRS configuration type using one symbol, the DMRS antenna ports corresponding to the CDM group A are # 0 and # 1, the DMRS antenna ports corresponding to the CDM group B are # 2 and # 3, The DMRS antenna ports corresponding to C are # 4 and # 5.

The DMRS antenna ports corresponding to the CDM group A are # 0, # 1, # 6 and # 7, and the DMRS antenna ports corresponding to the CDM group B are # 2, # 3, # 8, and # 9, and the DMRS antenna ports corresponding to the CDM group C are # 4, # 5, # 10, and # 11.

Here, the CDM group is composed of antenna ports using the same RE pattern. The antenna ports share the same RE resources and can be divided into FD-OCC and / or FD-OCC.

On the other hand, if two codewords (codeword 0 and codeword 1 are used) are indicated, the table is shown in Table 12 below.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number (Number of)
Co-scheduled CDM group (s) 0 One 5 # 0, # 1,
# 2, # 3, # 4 0 One One 6 # 0, # 1, # 2,
# 3, # 4, # 5 0 2 2 5 # 0, # 1,
# 2, # 3, # 8 0 3 2 6 # 0, # 1, # 6,
# 2, # 3, # 8 0 4 2 7 # 0, # 1, # 6,
# 2, # 3, # 8, # 9 0 5 2 8 # 0, # 1, # 6, # 7
# 2, # 3, # 8, # 9 0 6 Reserved .... ... 127 Reserved

The order of the bit values in Table 12 may be reversed, but the messages included in Table 12 are the same, and the specific contents thereof may be in accordance with FIGS. 2 to 6 and Tables 2 to 8.

In the case of the second type of DMRS configuration based on the CDM, the base station uses the number of DMRS symbols (one or two) used for the corresponding terminal, the number of layers, the antenna port number, and the scheduled CDM group (The first table according to Table 11 and the second table according to Table 12) for each codeword. In this case, the first table has 72 actual bit values (bit value 0 to bit value 71) except for the " Reserved " bit value. The second table has six actual bit values (bit value 0 to bit value 5) except for the " Reserved " bit value. Each table value can be indicated via a 7-bit signaling field included in the DCI. This is because 7-bit signaling is required in consideration of the maximum 72 configurations of Table 11.

In the case of the second DMRS configuration type based on the CDM, the base station can determine the number (one or two) of DMRS symbols used for the corresponding terminal, the number of layers, the antenna port number, and the scheduled CDM group Can be indicated by four tables for each symbol and codeword. In this case, the first table may consist of only one symbol in Table 11. That is, the first table may include only one symbol configuration when one of the configurations of Table 11 is used. At this time, the first table has 23 substantial bit values (bit value 0 to bit value 22) except for the "Reserved" bit value. The second table may consist of only two symbols in Table 11. That is, the second table may include only two symbol configurations when the codeword is one of the configurations of Table 11. [ At this time, the second table has 49 substantial bit values (bit value 23 to bit value 71) except for the "Reserved" bit value. The third table may consist of only one symbol in Table 12. That is, the third table may include only one symbol configuration when there are two coat words among the configurations of Table 12. At this time, the third table has two substantial bit values (bit value 0 to bit value 1) except for the "Reserved" bit value. The fourth table may consist of only two symbols in Table 12. That is, the fourth table may include only two symbol configurations when there are two codewords among the configurations of Table 12. [ In this case, the fourth table has four substantial bit values (bit value 2 to bit value 5) except for the "Reserved" bit value. Each table value can be indicated via a 6-bit signaling field included in the DCI. This is because 6-bit signaling is required considering a maximum of 49 configurations of two symbol configurations in Table 11. In this case, it can be indicated through a separate 1-bit signaling field included in the DCI whether the corresponding table is composed of one symbol or two symbols.

Meanwhile, the BS may follow the rules mentioned in Table 13 below in order to indicate the CDM group scheduled together for rate-matching in the case of the second DMRS configuration type based on the CDM.

Occation Configuring DMRS The specific terminal uses
CDM Group The number of scheduled CDM groups that are additionally considered together Case 1 Configuration type 1 Comb pattern A 0 Case 2 Comb pattern A 1 (Comb pattern B) Case 3 Comb pattern B 1 (Comb pattern A) Case 4 Comb pattern A, B 0 Case 5 Configuration type 2 CDM group A 0 Case 6 CDM group A 2 (CDM group B, C) Case 7 CDM group B 1 (CDM group A) Case 8 CDM group B 2 (CDM group A, C) Case 9 CDM group C 2 (CDM group A, B) Case 10 CDM group A, B 0 Case 11 CDM group A, B 1 (CDM group C) Case 12 CDM groups A, B, C 0

In Table 8, when the CDM group used by a particular UE for the second DMRS configuration type is CDM group A, the number of the simultaneously scheduled CDM groups considered together may be 0 or 1 (in this case, CDM group B (In this case, the CDM group B and the CDM group C are scheduled together), and so on.

However, in Table 13, if the CDM group used by a particular terminal for the second DMRS configuration type is a CDM group A, then the number of concurrently scheduled CDM groups to be considered together may be 0, or may be 1 or 2 The CDM group B is scheduled together, or the CDM group B and the CDM group C are scheduled together).

  That is, in order to reduce the number of cases in Table 13, when the CDM group used by the specific terminal for the second DMRS configuration type is the CDM group A, the number of the simultaneously scheduled CDM groups to be considered together is two Can be signaled together. In this case, since the UE does not know whether the scheduled CDM group is one or two, it can perform rate matching on the assumption that there are two CDM groups. Accordingly, Table 11 can be changed to the following Table 14 according to the rules mentioned in Table 13. In this case, however, Table 12 can be used as it is.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number (Number of)
Co-scheduled CDM group (s) 0 One One #0 0 One One One #0 2 (CDM group B, C) 2 One One #One 0 3 One One #One 2 (CDM group B, C) 4 One One #2 1 (CDM group A) 5 One One #2 2 (CDM group A, C) 6 One One # 3 1 (CDM group A) 7 One One # 3 2 (CDM group A, C) 8 One One #4 2 (CDM group A, B) 9 One One # 5 2 (CDM group A, B) 10 One 2 # 0, # 1 0 11 One 2 # 0, # 1 2 (CDM group B, C) 12 One 2 # 2, # 3 1 (CDM group A) 13 One 2 # 2, # 3 2 (CDM group A, C) 14 One 2 # 4, # 5 2 (CDM group A, B) 15 One 3 # 0, # 1, # 2 0 16 One 3 # 0, # 1, # 2 1 (CDM group C) 17 One 3 # 3, # 4, # 5 1 (CDM group A) 18 One 4 # 0, # 1, # 2, # 3 0 19 One 4 # 0, # 1, # 2, # 3 1 (CDM group C) 20 2 One #0 0 21 2 One #0 2 (CDM group B, C) 22 2 One #One 0 23 2 One #One 2 (CDM group B, C) 24 2 One #2 1 (CDM group A) 25 2 One #2 2 (CDM group A, C) 26 2 One # 3 1 (CDM group A) 27 2 One # 3 2 (CDM group A, C) 28 2 One #4 2 (CDM group A, B) 29 2 One # 5 2 (CDM group A, B) 30 2 One # 6 0 31 2 One # 6 2 (CDM group B, C) 32 2 One # 7 0 33 2 One # 7 2 (CDM group B, C) 34 2 One #8 1 (CDM group A) 35 2 One #8 2 (CDM group A, C) 36 2 One # 9 1 (CDM group A) 37 2 One # 9 2 (CDM group A, C) 38 2 One # 10 2 (CDM group A, B) 39 2 One # 11 2 (CDM group A, B) 40 2 2 # 0, # 1 0 41 2 2 # 0, # 1 2 (CDM group B, C) 42 2 2 # 2, # 3 1 (CDM group A) 43 2 2 # 2, # 3 2 (CDM group A, C) 44 2 2 # 4, # 5 2 (CDM group B, C) 45 2 2 # 6, # 7 0 46 2 2 # 6, # 7 2 (CDM group B, C) 47 2 2 # 8, # 9 1 (CDM group A) 48 2 2 # 8, # 9 2 (CDM group A, C) 49 2 2 # 10, # 11 2 (CDM group B, C) 50 2 3 # 0, # 1, # 6 0 51 2 3 # 0, # 1, # 6 2 (CDM group B, C) 52 2 3 # 2, # 3, # 8 1 (CDM group A) 53 2 3 # 2, # 3, # 8 2 (CDM group A, C) 54 2 3 # 4, # 5, # 10 2 (CDM group A, B) 55 2 3 # 7, # 9, # 11 0 56 2 4 # 0, # 1, # 6, # 7 0 57 2 4 # 0, # 1, # 6, # 7 2 (CDM group B, C) 58 2 4 # 2, # 3, # 8, # 9 1 (CDM group A) 59 2 4 # 2, # 3, # 8, # 9 2 (CDM group A, C) 60 2 4 # 4, # 5, # 10, # 11 2 (CDM group A, B) 61 Reserved 62 Reserved 63 Reserved

Meanwhile, in the case of the second DMRS configuration type, the BS determines the number (1 or 2) of DMRS symbols used for the UE, the number of layers, the antenna port number, and the scheduled CDM group (or the number of the scheduled CDM groups) (The first table according to Table 14 and the second table according to Table 13) for each codeword. In this case, the first table has 61 actual bit values (bit value 0 to bit value 60) except for the " Reserved " bit value. The second table has six actual bit values (bit value 0 to bit value 5) except for the " Reserved " bit value. Each table value can be indicated via a 6-bit signaling field included in the DCI. This is because 6-bit signaling is required considering a maximum of 61 configurations shown in Table 14.

As a second embodiment, the base station follows the rules mentioned in Table 13 and Table 14 for the first DMRS configuration type and the same as the first embodiment for the second DMRS configuration type, Rather than follow the rules mentioned in Tables 7 and 8 for directing the CDM group, the rules mentioned in Table 15 below can be followed.

Occation Configuring DMRS The specific terminal uses
CDM Group Additional Scheduled CDM Group Together Considered Case 1 Configuration type 1 Comb pattern A 0 Case 2 Comb pattern A One Case 3 Comb pattern B 0 Case 4 Comb pattern A, B 0 Case 5 Configuration type 2 CDM group A 0 Case 6 CDM group A One Case 7 CDM group B 0 Case 8 CDM group B One Case 9 CDM group C 0 Case 10 CDM group A, B 0 Case 11 CDM group A, B One Case 12 CDM groups A, B, C 0

Referring to Table 15, a value of 0 or 1 is indicated for values of the co-scheduled CDM group type to be considered additionally. If the value is 0, for the first DMRS configuration type, 1) if the CDM group used by the specific terminal is Comb Pattern A, it is regarded that only Comb Pattern A is used for all terminals paired with MU-MIMO (Case 1), and 2) when the CDM group used by the specific terminal is Comb Pattern B, it is assumed that Comb Pattern A and Comb Pattern B are used for all terminals paired with MU-MIMO (Case 3, Comb Pattern A is assigned and the Comb pattern B is assigned), and 3) when the CDM group used by the specific terminal is Comb Pattern A and Comb Pattern B, Comb Pattern A And Comb pattern B are used (Case 4).

If the value is 0, it is assumed that 1) the CDM group used by the specific terminal is the CDM group A, and that only the CDM group A is used for all terminals paired with MU-MIMO (Case 5), and 2) when the CDM group used by a particular UE is a CDM group B, only CDM group A and CDM group B are considered to be used for all UEs paired with MU-MIMO A is allocated and then CDM group B is allocated), and 3) when the CDM group used by the specific UE is the CDM group C, the CDM group A and the CDM group B are allocated to all the UEs paired with the MU- And CDM group C are assumed to be used (Case 9, CDM group A is allocated, CDM group B is allocated, and CDM group C is then allocated), and 4) CDM group In the case of the CDM group A and the CDM group B, the MU- (CDM group A and CDM group B) (Case 10), and 5) when the CDM group used by the specific terminal is CDM group A, CDM group B and CDM group C, MU-MIMO It is assumed that CDM group A, CDM group B and CDM group C are used for all paired terminals (Case 11).

  That is, when 0 is indicated as a value for the scheduled CDM group type to be considered additionally, only up to the CDM group used by a specific UE can be used for all UEs paired with MU-MIMO. For example, if the CDM group used by a particular UE is a CDM group A, only the CDM group A is allocated to the CDM group B, and the CDM group A is assigned to the CDM group B, C, CDM group A, CDM group B and CDM group C are all applicable since CDM group A is allocated, CDM group B is allocated, and CDM group C is assigned.

If the value is 1, it can be regarded that the CDM group is used for all terminals paired with the MU-MIMO. That is, in the case of the first DMRS configuration type, the Comb pattern A and the Comb pattern B are all used (Case 2). In the case of the second DMRS configuration type, the CDM group A, the CDM group B and the CDM group C are all used (Case 6, Case 8, Case 11).

Thus, considering Table 15, Table 16 and Table 17 below may be used for the first DMRS configuration type for the second embodiment, and Table 18 and Table 19 below may be used for the second DMRS configuration type.

The following Table 16 shows a case where one codeword (codeword 0 is used and codeword 1 is not used) for the first DMRS configuration type is indicated.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number Type of
Co-scheduled CDM group (s) 0 One One #0 0 One One One #0 One 2 One One #One 0 3 One One #One One 4 One One #2 0 5 One One # 3 0 6 One 2 # 0, # 1 0 7 One 2 # 0, # 1 One 8 One 2 # 2, # 3 0 9 One 3 # 0 ~ # 2 0 10 One 4 # 0 ~ # 3 0 11 2 One #0 0 12 2 One #0 One 13 2 One #One 0 14 2 One #One One 15 2 One #2 0 16 2 One # 3 0 17 2 One #4 0 18 2 One #4 One 19 2 One # 5 0 20 2 One # 5 One 21 2 One # 6 0 22 2 One # 7 0 23 2 2 # 0, # 1 0 24 2 2 # 0, # 1 One 25 2 2 # 2, # 3 0 26 2 2 # 4, # 5 0 27 2 2 # 4, # 5 One 28 2 2 # 6, # 7 0 29 2 3 # 0, # 1, # 4 0 30 2 3 # 0, # 1, # 4 One 31 2 3 # 2, # 3, # 6 0 32 2 4 # 0, # 1, # 4, # 5 0 33 2 4 # 0, # 1, # 4, # 5 One 34 2 4 # 2, # 3, # 6, # 7 0 35 Reserved ... ... 63 Reserved

The order of the bit values in Table 16 may be reversed, but the messages included in Table 16 are the same, and the specific contents thereof may be in accordance with FIGS. 2 to 6 and Tables 2 to 5 and Table 15.

In Table 16, DMRS antenna ports corresponding to Comb pattern A and Comb pattern B are as follows.

In the case of the first DMRS configuration type using one symbol, the DMRS antenna ports corresponding to Comb pattern A are # 0 and # 1, and the DMRS antenna ports corresponding to Comb pattern B are # 2 and # 3.

The DMRS antenna ports corresponding to the Comb pattern A are # 0, # 1, # 4 and # 5, and the DMRS antenna ports corresponding to the Comb pattern B are the # 2, # 3, # 6, and # 7.

Here, the Comb pattern group is composed of antenna ports using the same RE pattern. The antenna ports share the same RE resources and can be divided into a CS value and / or an FD-OCC. This may be defined as a CDM group as in the second DMRS configuration pattern.

Table 17 below shows the case where two codewords (codeword 0 and codeword 1 are used) for the first DMRS configuration type are indicated.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number Type of
Co-scheduled CDM group (s) 0 2 5 # 0, # 1,
# 2, # 3, # 6 0 One 2 6 # 0, # 1, # 4,
# 2, # 3, # 6 0 2 2 7 # 0, # 1, # 4,
# 2, # 3, # 6, # 7 0 3 2 8 # 0, # 1, # 4, # 5,
# 2, # 3, # 6, # 7 0 4 Reserved ... ... 63 Reserved

The order of the bit values in Table 17 can be reversed, but the messages included in Table 17 are the same, and the detailed contents thereof can be in accordance with FIGS. 2 to 6 and Tables 2 to 5 and Table 15.

The following Table 18 shows a case where one codeword (codeword 0 is used and codeword 1 is not used) for the second DMRS configuration type is indicated.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number Type of
Co-scheduled CDM group (s) 0 One One #0 0 One One One #0 One 2 One One #One 0 3 One One #One One 4 One One #2 0 5 One One #2 One 6 One One # 3 0 7 One One # 3 One 8 One One #4 0 9 One One # 5 0 10 One 2 # 0, # 1 0 11 One 2 # 0, # 1 One 12 One 2 # 2, # 3 0 13 One 2 # 2, # 3 One 14 One 2 # 4, # 5 0 15 One 3 # 0, # 1, # 2 0 16 One 3 # 0, # 1, # 2 One 17 One 3 # 3, # 4, # 5 0 18 One 4 # 0, # 1, # 2, # 3 0 19 One 4 # 0, # 1, # 2, # 3 One 20 2 One #0 0 21 2 One #0 One 22 2 One #One 0 23 2 One #One One 24 2 One #2 0 25 2 One #2 One 26 2 One # 3 0 27 2 One # 3 One 28 2 One #4 0 29 2 One # 5 0 30 2 One # 6 0 31 2 One # 6 One 32 2 One # 7 0 33 2 One # 7 One 34 2 One #8 0 35 2 One #8 One 36 2 One # 9 0 37 2 One # 9 One 38 2 One # 10 0 39 2 One # 11 0 40 2 2 # 0, # 1 0 41 2 2 # 0, # 1 One 42 2 2 # 2, # 3 0 43 2 2 # 2, # 3 One 44 2 2 # 4, # 5 0 45 2 2 # 6, # 7 0 46 2 2 # 6, # 7 One 47 2 2 # 8, # 9 0 48 2 2 # 8, # 9 One 49 2 2 # 10, # 11 0 50 2 3 # 0, # 1, # 6 0 51 2 3 # 0, # 1, # 6 One 52 2 3 # 2, # 3, # 8 0 53 2 3 # 2, # 3, # 8 One 54 2 3 # 4, # 5, # 10 0 55 2 3 # 7, # 9, # 11 0 56 2 4 # 0, # 1, # 6, # 7 0 57 2 4 # 0, # 1, # 6, # 7 One 58 2 4 # 2, # 3, # 8, # 9 0 59 2 4 # 2, # 3, # 8, # 9 One 60 2 4 # 4, # 5, # 10, # 11 0 61 Reserved 62 Reserved 63 Reserved

The order of the bit values in Table 18 may be reversed, but the messages included in Table 18 are the same, and the specific contents thereof may be in accordance with FIGS. 2 to 6 and Tables 2 to 5 and Table 15.

In Table 18, the DMRS antenna ports corresponding to CDM group A, CDM group B and CDM group C are as follows.

In the case of the second DMRS configuration type using one symbol, the DMRS antenna ports corresponding to the CDM group A are # 0 and # 1, the DMRS antenna ports corresponding to the CDM group B are # 2 and # 3, The DMRS antenna ports corresponding to C are # 4 and # 5.

The DMRS antenna ports corresponding to the CDM group A are # 0, # 1, # 6 and # 7, and the DMRS antenna ports corresponding to the CDM group B are # 2, # 3, # 8, and # 9, and the DMRS antenna ports corresponding to the CDM group C are # 4, # 5, # 10, and # 11.

Here, the CDM group is composed of antenna ports using the same RE pattern. The antenna ports share the same RE resources and can be divided into FD-OCC and / or FD-OCC.

The following Table 19 shows the case where two codewords (codeword 0 and codeword 1 are used) are indicated for the second DMRS configuration type.

Bit value Number of
Symbol (s) Number of
layer (s) Antenna port number (Number of)
Co-scheduled CDM group (s) 0 One 5 # 0, # 1,
# 2, # 3, # 4 0 One One 6 # 0, # 1, # 2,
# 3, # 4, # 5 0 2 2 5 # 0, # 1,
# 2, # 3, # 8 0 3 2 6 # 0, # 1, # 6,
# 2, # 3, # 8 0 4 2 7 # 0, # 1, # 6,
# 2, # 3, # 8, # 9 0 5 2 8 # 0, # 1, # 6, # 7
# 2, # 3, # 8, # 9 0 6 Reserved .... ... 127 Reserved

The order of the bit values in Table 19 can be reversed, but the messages included in Table 19 are the same, and the concrete contents thereof can be followed from FIGS. 2 to 6 and Tables 2 to 5 and Table 15.

7 is a diagram illustrating a method for transmitting a downlink DMRS according to an embodiment of the present invention.

7, if the DMRS configuration type of the DMRS (DL DMRS) to be transmitted to the UE is determined among the first DMRS configuration type and the second DMRS configuration type in the downlink (S710), the base station transmits information on the DMRS to the RRC (S720) through a high layer signaling such as Resource Control. Then, the BS determines the CDM group (s) to be used according to the number of layers of the DMRS, the antenna port number, the number of symbols and the MU-MIMO to be transmitted to the MS in the determined DMRS configuration type (S730) To the terminal (S730). At this time, the base station may configure the DCI according to at least one of the specific rules mentioned in Tables 1 to 19 above.

Then, the base station transmits information about the CDM group (s) to be used according to the determined DMR configuration type, the number of layers of the DMRS to be transmitted to the UE in the determined DMRS configuration type, the antenna port number, the number of symbols, and the MU- (S750), and transmits the downlink DMRS to the mobile station (S760).

In this case, the terminal checks the DMRS configuration type of the DMRS received from the base station through an RRC message received from the base station, and determines the number of layers of the DMRS transmitted from the base station to the terminal in the DMRS configuration type, , The number of symbols and the information about the scheduled CDM group together with the DCI received from the BS and then constructs a DMRS based on the received DCI and compares the DMRS with the DMRS received from the BS to perform channel estimation (S770).

8 is a diagram illustrating a method for transmitting an uplink DMRS in an embodiment of the present invention.

Referring to FIG. 8, the BS determines the DMRS configuration type of the DMRS (UL DMRS) to be transmitted to the BS by the first DMRS configuration type and the second DMRS configuration type in the uplink (S810) (Step S820). The MS determines the CDM group (s) to use according to whether the number of the DMRS layer, the antenna port number, the number of symbols, and the MU-MIMO to be transmitted to the BS in the determined DMRS configuration type (S830) (S840).

The terminal checks the DMRS configuration type of the DMRS to be transmitted to the base station through an RRC message or the like received from the base station. The number of layers, the antenna port number, and the number of symbols of the DMRS to be transmitted from the terminal to the base station in the DMRS configuration type After confirming the information on the scheduled CDM group through the DCI received from the BS, the DMRS can be configured based on the DCRS (S850) and transmitted to the BS (S860).

In step S870, the base station configures the DMRS according to the information and performs channel estimation by comparing the DMRS with the DMRS received from the terminal.

9 is a block diagram illustrating a wireless communication system in accordance with an embodiment of the present invention.

Referring to FIG. 9, the wireless communication system according to the present invention includes a base station 900 and a terminal 950.

The base station 900 includes a processor 905, an RF unit (radio frequency unit) 910, and a memory 915. The memory 915 is coupled to the processor 905 and stores various information for driving the processor 905. [ The RF unit 910 is coupled to the processor 905 to transmit and / or receive wireless signals. For example, the RF unit 910 may transmit a downlink signal including information related to the published DMRS configuration from the terminal 950, or may transmit the configured DMRS. Also, the RF unit 915 can receive the uplink DMRS from the terminal 950.

The processor 905 implements the functions, processes and / or methods suggested herein. Specifically, the processor 905 can control the above-described operation of the base station 900 to be performed.

For example, the processor 905 may include a DMRS configuration type determination unit 906, a DCI information generation unit 907, and a channel estimation unit 908.

The DMRS configuration type determination unit 906 may determine a DMRS configuration type to be used for the terminal 950 among the first DMRS configuration type and the second DMRS configuration type.

The DCI information generation unit 907 generates a DMRS to be transmitted to the terminal 950 in the DMRS configuration type determined by the DMRS configuration type determination unit 906 or a layer number, an antenna port number, a symbol number, and an MU -MIMO can be used to determine the CDM group (s) to use. For this, the DCI information generation unit 907 may use at least one of the specific rules mentioned in Tables 1 to 19 published herein.

The channel estimation unit 908 compares the DMRS configured based on the information determined by the DMRS configuration type determination unit 906 and the DCI information generation unit 907 with the DMRS (UL DMRS) received through the RF unit 910, Estimation can be performed.

The memory 915 stores at least one of the information for Tables 1 through 19 disclosed herein and may provide it to the processor 905 in accordance with the requirements of the processor 905. [

The terminal 950 includes an RF unit (radio frequency unit) 955, a processor 960, and a memory 965. The memory 965 is coupled to the processor 960 to store various information for driving the processor 960. The RF unit 955 is connected to the processor 960 to transmit and / or receive wireless signals. Processor 960 implements the functions, processes, and / or methods suggested herein. The operation of the terminal 950 in the above-described embodiments may be implemented by the processor 960. [ The processor 960 configures the DMRS according to the DMRS-related information received from the base station 900, and performs channel estimation.

For example, the processor 960 may include a DMRS configuration verifier 961, a DMRS configurer 962, and a channel estimator 963.

The DMRS configuration confirmation unit 961 can confirm the configuration of the DMRS applied to the terminal 950 through the RRC message received from the base station 900, the DCI, and the like.

The DMRS configuration unit 962 may configure a DMRS to be transmitted to the base station 900 based on the information confirmed by the DMRS configuration confirmation unit 961. [

The channel estimation unit 963 can estimate the channel by comparing the DMRS configured based on the information confirmed by the DMRS configuration confirmation unit 961 with the DMRS received from the base station 900. [

Claims (1)

A method for transmitting a Demodulation Reference Signal (DMRS) to a terminal in a wireless communication system,
Determining a DMRS configuration type of a DMRS to be transmitted to a terminal among the plurality of DMRS configuration types;
Transmitting information on the determined DMRS type to the terminal through high layer signaling;
Determining a Code Division Multiplexing (CDM) group to be used according to the number of layers of the DMRS, the antenna port number, the number of symbols, and the MU-MIMO of the DMRS to be transmitted to the UE in the determined DMRS configuration type and transmitting the determined information to the MS ; And
Configuring the DMRS according to the determined information and transmitting the DMRS to the terminal
/ RTI >

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