WO2025147174A1 - Method and apparatus for transmitting/receiving phase tracking reference signal - Google Patents

Abstract

A method according to one embodiment of the present specification comprises the steps of: receiving DCI from a base station; and transmitting a PTRS to the base station. The DCI includes a PTRS-DMRS association field. A PTRS port related to the PTRS is related to codebook-based uplink transmission based on one or more antenna ports. On the basis that the number of one or more antenna ports is 3 and two PTRS ports are configured, the number of bits of the PTRS-DMRS association field is 1. One of two DMRS ports that share a first PTRS port is indicated on the basis of the PTRS-DMRS association field, and the two DMRS ports are related to two antenna ports from among three antenna ports. A second PTRS port is associated with the remaining antenna port from among the three antenna ports.

Description

Method and device for transmitting and receiving phase tracking reference signals

The present specification relates to a method and device for transmitting and receiving a phase tracking reference signal.

Mobile communication systems were developed to provide voice services while ensuring user activity. However, mobile communication systems have expanded their scope to include data services as well as voice, and currently, due to the explosive increase in traffic, resource shortages are occurring and users are demanding higher-speed services, so more advanced mobile communication systems are required.

The requirements for the next generation mobile communication system are that it should be able to accommodate explosive data traffic, dramatically increase the data rate per user, accommodate a greatly increased number of connected devices, support very low end-to-end latency, and support high energy efficiency. To this end, various technologies are being studied, including dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband support, and device networking.

According to the existing operation, 1/2/4/8 Tx uplink transmission is supported and DMRS-PTRS association is indicated based on this. In case of rank 1 (antenna port), PTRS-DMRS association field is 0 bit, in case of rank 2~4 (2 or 4 antenna ports), PTRS-DMRS association field is 2 bit, and in case of rank > 4 (8 antenna ports), PTRS-DMRS association field is 4 bit.

In Rel-19 MIMO, 3Tx uplink transmission of a terminal with single or multiple panels is considered for a 3 Tx antenna UE. A method for indicating PTRS-DMRS association for each PTRS port that is configured to support 3 Tx uplink transmission introduced in Rel-19 is required.

The purpose of this specification is to propose a method for indicating PTRS-DMRS association in codebook-based uplink transmission based on three antenna ports.

The technical problems to be achieved in this specification are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary knowledge in the technical field to which this specification belongs from the description below.

A method according to one embodiment of the present disclosure includes the steps of receiving downlink control information (DCI) from a base station and transmitting a phase tracking reference signal (PTRS) to the base station.

The above DCI includes a PTRS-DMRS association field. The PTRS port associated with the PTRS is associated with codebook based UL transmission based on one or more antenna ports.

Based on the number of the one or more antenna ports being 3 and 2 PTRS ports being set: the number of bits of the PTRS-DMRS association field is 1. Based on the PTRS-DMRS association field, one of the two DMRS ports sharing the first PTRS port is indicated, and the two DMRS ports are associated with two of the three antenna ports. The second PTRS port is characterized in that it is associated with the remaining antenna port of the three antenna ports.

Wherein the number of the one or more antenna ports is 4, and based on the two PTRS ports being set: the number of bits of the PTRS-DMRS association field may be 2. One of the two first DMRS ports sharing the first PTRS port may be indicated based on a value of the MSB (Most Significant Bit) of the PTRS-DMRS association field. One of the two second DMRS ports sharing the second PTRS port may be indicated based on a value of the LSB (Least Significant Bit) of the PTRS-DMRS association field. The two first DMRS ports may be associated with two antenna ports among the four antenna ports, and the two second DMRS ports may be associated with the remaining two antenna ports among the four antenna ports.

Wherein the number of the one or more antenna ports is 8 and the two PTRS ports are set: the number of bits of the PTRS-DMRS association field may be 4. One of the four first DMRS ports sharing the first PTRS port may be indicated based on values of two Most Significant Bits (MSBs) of the PTRS-DMRS association field. One of the four second DMRS ports sharing the second PTRS port may be indicated based on values of two Least Significant Bits (LSBs) of the PTRS-DMRS association field. The four first DMRS ports may be associated with four antenna ports among the eight antenna ports. The four second DMRS ports may be associated with the remaining four antenna ports among the eight antenna ports.

The above DCI may include precoding information and number of layers fields.

A Transmitted Precoding Matrix Indicator (TPMI) may be indicated based on the above precoding information and layer number fields.

A precoding matrix based on the above TPMI may include at least one column consisting of three rows. The three rows may be associated with the three antenna ports.

The above precoding matrix may be associated with i) partial-coherent codebook based UL transmission or ii) non-coherent codebook based UL transmission.

The two antenna ports may be associated with two of three elements in the at least one column. Each of the two elements may be based on a value other than zero.

The above two antenna ports may be antenna ports 1000 and 1002. The remaining antenna port may be antenna port 1001.

Based on the number of the one or more antenna ports being 3 and 1 PTRS port being configured: the number of bits of the PTRS-DMRS association field may be 1. Based on the PTRS-DMRS association field, one of the two DMRS ports sharing the 1 PTRS port may be indicated.

The above two DMRS ports can be associated with specific two antenna ports among the above three antenna ports.

The above two specific antenna ports may be associated with partial-coherent codebook based UL transmission.

The above-mentioned two specific antenna ports may include i) one port determined from among two ports related to partial-coherent codebook based UL transmission and ii) one port remaining from among the three ports excluding the two ports.

The above two specific antenna ports can be determined based on the order of the antenna port index among the above three ports.

A terminal according to another embodiment of the present disclosure comprises one or more transceivers, one or more processors, and one or more memories coupled to the one or more processors and storing instructions.

The above instructions are characterized in that they cause the terminal to perform all steps of any one of the above methods based on being executed by the one or more processors.

In another embodiment of the present disclosure, a device comprises one or more memories and one or more processors functionally connected to the one or more memories, characterized in that the one or more memories store instructions that cause the device to perform all steps of any one of the above methods based on being executed by the one or more processors.

A non-transitory computer-readable storage medium according to another embodiment of the present disclosure stores instructions, characterized in that the instructions, when executed by one or more processors, cause a terminal to perform all steps of one of the methods.

A method according to another embodiment of the present specification includes the steps of transmitting downlink control information (DCI) to a terminal and receiving a phase tracking reference signal (PTRS) from the terminal.

The above DCI includes a PTRS-DMRS association field. The PTRS port associated with the PTRS is associated with codebook based UL transmission based on one or more antenna ports.

Based on the number of the one or more antenna ports being 3 and 2 PTRS ports being set: the number of bits of the PTRS-DMRS association field is 1. Based on the PTRS-DMRS association field, one of the two DMRS ports sharing the first PTRS port is indicated. The two DMRS ports are associated with two of the three antenna ports. The second PTRS port is characterized in that it is associated with the remaining antenna port of the three antenna ports.

A base station according to another embodiment of the present disclosure includes one or more transceivers, one or more processors, and one or more memories coupled to the one or more processors and storing instructions.

The above instructions are characterized in that they cause the base station to perform all steps of the method based on being executed by the one or more processors.

According to an embodiment of the present specification, the DCI overhead required to indicate PTRS-DMRS association related to 3Tx UL transmission can be reduced compared to the existing method in which the number of bits of a PTRS-DMRS association field is determined by considering the number of ranks.

The effects that can be obtained from this specification are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which this specification belongs from the description below.

Figure 1 is a diagram showing an example of uplink transmission and reception operations.

FIG. 2 is a flowchart illustrating a method according to one embodiment of the present specification.

FIG. 3 is a flowchart illustrating a method according to another embodiment of the present specification.

FIG. 4 is a drawing showing the configuration of a first device and a second device according to an embodiment of the present specification.

Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below together with the accompanying drawings is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present disclosure.

In some cases, to avoid ambiguity in the concepts of this specification, well-known structures and devices may be omitted or illustrated in block diagram format focusing on the core functions of each structure and device.

Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In the downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In the uplink, a transmitter may be part of a terminal, and a receiver may be part of a base station. The base station may be expressed as a first communication device, and the terminal may be expressed as a second communication device. A base station (BS) may be replaced by terms such as a fixed station, Node B, eNB (evolved-NodeB), gNB (Next Generation NodeB), BTS (base transceiver system), access point (AP: Access Point), network (5G network), AI system, RSU (road side unit), vehicle, robot, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device, etc. In addition, the terminal may be fixed or mobile, and may be replaced with terms such as UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), MTC (Machine-Type Communication) device, M2M (Machine-to-Machine) device, D2D (Device-to-Device) device, vehicle, robot, AI module, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device, etc.

DMRS (demodulation reference signal)

DMRS Reception Procedure

Let's look at DMRS related operations for PDSCH reception.

When receiving a PDSCH scheduled by DCI format 1_0 or before any dedicated higher layer configuration of the dmrs-AdditionalPosition, maxLength and dmrs-Type parameters, the UE assumes that no PDSCH exists in any symbol carrying DM-RS except for the PDSCH with an allocated duration of 2 symbols with PDSCH mapping type B, a single symbol front-loaded DM-RS of configuration type 1 is transmitted on DM-RS port 1000, and none of the remaining orthogonal antenna ports are associated with PDSCH transmission to other UEs.

Additionally, for a PDSCH with mapping type A, the UE assumes that there are dmrs-AdditionalPosition='pos2' and at most two additional single-symbol DM-RS in the slot according to the PDSCH duration indicated in the DCI. For a PDSCH with an allocation duration of 7 symbols for a normal CP or 6 symbols for an extended CP with mapping type B, when a front-loaded DM-RS symbol is in the 1st or 2nd symbol of the PDSCH allocation duration, respectively, the UE assumes that one additional single-symbol DM-RS is present in the 5th or 6th symbol. Otherwise, the UE assumes that no additional DM-RS symbol is present. And, for a PDSCH having an allocation duration of 4 symbols with mapping type B, the UE assumes that no additional DM-RS exists, and for a PDSCH having an allocation duration of 2 symbols with mapping type B, the UE assumes that no additional DM-RS exists, and the UE assumes that the PDSCH exists within a symbol carrying the DM-RS.

When receiving a PDSCH scheduled by DCI format 1_1 by a PDCCH having a CRC scrambled by C-RNTI, MCS-C-RNTI or CS (configured scheduling)-RNTI,

- The terminal can be set to the upper layer parameter dmrs-Type, and the set DM-RS configuration type is used to receive PDSCH.

- The terminal can set the maximum number of front-loaded DM-RS symbols for PDSCH by the upper layer parameter maxLength given by DMRS-DownlinkConfig.

The terminal can schedule the number of DM-RS ports by antenna port index of DCI format 1_1.

The DMRS configuration type is configured by the dmrs-Type parameter in the DMRS-DownlinkConfig IE in Table 1. DMRS configuration type 1 has higher RS density in the frequency domain and supports up to 4(8) ports for single(double)-symbol DMRS. And, DMRS configuration type 1 supports length 2 F-CDM and FDM for single-symbol DMRS, and length 2 F/T-CDM and FDM for double-symbol DMRS. DMRS configuration type 2 supports more DMRS antenna ports and supports up to 6(12) ports for single(double)-symbol DMRS.

Table 1 below shows an example of the DMRS-DownlinkConfig IE used to configure downlink DMRS for PDSCH.

In Table 1, the dmrs-AdditionalPosition parameter indicates the position of additional DM-RS in DL, and if the parameter does not exist, the UE applies the value pos2. The dmrs-Type parameter indicates the selection of DMRS type to be used for DL, and if the parameter does not exist, the UE uses DMRS type 1. The maxLength parameter indicates the maximum number of OFDM symbols for DL front loaded DMRS, and len1 corresponds to the value 1. The PhaseTrackingRS parameter configures DL PTRS, and if the parameter does not exist or is terminated, the UE assumes that there is no DL PTRS.

For DM-RS configuration type 1,

- If the terminal is scheduled with one code word and the antenna port mapping is assigned with indices of {2, 9, 10, 11 or 30}, or if the terminal is scheduled with two code words,

The terminal can assume that none of the remaining orthogonal antenna ports are associated with PDSCH transmissions to other terminals.

For DM-RS configuration type 2,

- When a terminal is scheduled with one codeword and the antenna port mapping is assigned with indices of {2,10,23}, or when a terminal is scheduled with two codewords,

The terminal can assume that none of the remaining orthogonal antenna ports are associated with PDSCH transmissions to other terminals.

An example of the DL DMRS procedure is described below.

The base station transmits DMRS configuration information to the terminal.

The above DMRS configuration information may refer to DMRS-DownlinkConfig IE. The DMRS-DownlinkConfig IE may include a dmrs-Type parameter, a dmrs-AdditionalPosition parameter, a maxLength parameter, a phaseTrackingRS parameter, etc.

The above dmrs-Type parameter is a parameter for selecting the DMRS configuration type to be used for DL. In NR, DMRS can be divided into two configuration types: (1) DMRS configuration type 1 and (2) DMRS configuration type 2. DMRS configuration type 1 is a type with a higher RS density in the frequency domain, and DMRS configuration type 2 is a type with more DMRS antenna ports.

The above dmrs-AdditionalPosition parameter is a parameter indicating the position of an additional DMRS in the DL. If the parameter does not exist, the terminal applies the pos2 value. The first position of the front-loaded DMRS is determined according to the PDSCH mapping type (type A or type B), and an additional DMRS may be configured to support a high speed terminal. The front-loaded DMRS occupies 1 or 2 consecutive OFDM symbols and is indicated by RRC signaling and DCI (downlink control information).

The above maxLength parameter is a parameter indicating the maximum number of OFDM symbols for DL front-loaded DMRS. The above phaseTrackingRS parameter is a parameter that sets DL PTRS. If the parameter does not exist or is terminated, the terminal assumes that there is no DL PTRS.

The above base station generates a sequence used for DMRS.

The sequence for the above DMRS is generated according to the mathematical expression 1 below.

는 3gpp TS 38.211 5.2.1에 정의되어 있다. 즉,

는 2개의 m-sequence들을 이용하는 길이-31의 골드 시퀀스일 수 있다. 슈도-랜덤 시퀀스 생성기(pseudo-random sequence generator)는 아래 수학식 2에 의해 초기화된다.The above pseudo-random sequence

is defined in 3gpp TS 38.211 5.2.1, i.e.

can be a length-31 Gold sequence using two m-sequences. The pseudo-random sequence generator is initialized by the following mathematical expression 2.

은 슬롯 내 OFDM 심볼의 넘버(number)이며,

는 프레임 내 슬롯 넘버이다.Here,

is the number of OFDM symbols in the slot,

is the slot number within the frame.

는, 만약 제공되고, PDSCH가 C-RNTI, MCS-C-RNTI 또는 CS-RNTI에 의해 스크램블된 CRC를 가진 DCI format 1_1을 사용하는 PDCCH에 의해 스케쥴된 경우, DMRS-DownlinkConfig IE 내 higher-layer parameter scramblingID0 및 scramblingID1에 의해 각각 주어진다.and,

is provided and scheduled by PDCCH using DCI format 1_1 with CRC scrambled by C-RNTI, MCS-C-RNTI or CS-RNTI, respectively, given by higher-layer parameters scramblingID0 and scramblingID1 in DMRS-DownlinkConfig IE.

는 만약 제공되고, PDSCH가 C-RNTI, MCS-C-RNTI, 또는 CS-RNTI에 의해 스크램블된 CRC를 가진 DCI format 1_0을 사용하는 PDCCH에 의해 스케쥴된 경우 DMRS-DownlinkConfig IE 내 higher-layer parameter scramblingID0에 의해 주어진다.-

is provided, if PDSCH is scheduled by PDCCH using DCI format 1_0 with CRC scrambled by C-RNTI, MCS-C-RNTI, or CS-RNTI, given by the higher-layer parameter scramblingID0 in DMRS-DownlinkConfig IE.

, 그렇지 않으면, quantity

는 DCI format 1_1이 사용되는 경우, PDSCH 전송과 연관된 DCI 내 DMRS 시퀀스 초기화 필드에 의해 주어진다.-

, otherwise, quantity

is given by the DMRS sequence initialization field in the DCI associated with the PDSCH transmission when DCI format 1_1 is used.

The base station maps the generated sequence to a resource element. Here, the resource element may have a meaning including at least one of time, frequency, antenna port, or code.

The above base station transmits the DMRS to the terminal on the above resource element. The terminal receives the PDSCH using the received DMRS.

UE DMRS Transmission Procedure

Let's look at DMRS-related operations for PUSCH reception. As we have seen, UL means signal transmission (or communication) from a terminal to a base station. UL DMRS-related operations are similar to DL DMRS-related operations discussed above, and the names of DL-related parameters can be replaced with the names of UL-related parameters.

That is, DMRS-DownlinkConfig IE can be replaced with DMRS-UplinkConfig IE, PDSCH mapping type can be replaced with PUSCH mapping type, and PDSCH can be replaced with PUSCH. And, in DL DMRS related operations, the base station can be replaced with the terminal, and the terminal can be replaced with the base station. Sequence generation for UL DMRS can be defined differently depending on whether transform precoding is enabled.

More specifically, DMRS uses a PN sequence when CP-OFDM (cyclic prefix orthogonal frequency division multiplexing) is used (or when transform precoding is not enabled), and uses a ZC sequence with a length of 30 or more when DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) is used (when transform precoding is enabled).

Table 2 below shows an example of a DMRS-UplinkConfig IE used to configure uplink DMRS for PUSCH.

In Table 2, the dmrs-AdditionalPosition parameter indicates the position for additional DM-RS in UL, and if the parameter is not present, the UE applies the value pos2. The dmrs-Type parameter indicates the selection of DMRS type to be used for UL, and if the parameter is not present, the UE uses DMRS type 1.

The maxLength parameter indicates the maximum number of OFDM symbols for UL front loaded DMRS, and len1 corresponds to the value 1. The PhaseTrackingRS parameter configures UL PTRS. The transformPrecodingDisabled parameter indicates DMRS related parameters for Cyclic Prefix OFDM. The transformPrecodingEnabled parameter indicates DMRS related parameters for DFT-s-OFDM (Transform Precoding).

Below, we will look at the UE DM-RS transmission procedure in more detail.

If the transmitted PUSCH is neither scheduled by DCI format 0_1 with CRC scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI nor corresponds to a configured grant, the UE uses a single symbol front-loaded DM-RS of configuration type 1 on DM-RS port 0, and the remaining REs that are not used for DM-RS in the symbols are not used for any PUSCH transmission except for a PUSCH with an allocated duration of 2 or less OFDM symbols with disabled transform precoding. Additional DM-RS can be transmitted depending on the scheduling type and the PUSCH duration considering whether frequency hopping is enabled.

When frequency hopping is disabled: The UE assumes that dmrs-AdditionalPosition is equal to 'pos2' and up to 2 additional DM-RS can be transmitted per PUSCH duration.

When frequency hopping is enabled: The UE assumes that dmrs-AdditionalPosition is equal to 'pos1' and at most one additional DM-RS can be transmitted per PUSCH duration.

When the transmitted PUSCH is scheduled by activation DCI format 0_0 with CRC scrambled by CS-RNTI, the UE uses a single symbol front-loaded DM-RS of a configuration type provided by a higher-layer parameter dmrs-Type of configuredGrantConfig on DM-RS port 0, and the remaining REs that are not used for DM-RS in the symbols are not used for any PUSCH transmission except for a PUSCH with an allocated duration of two or less OFDM symbols with disabled transform precoding, and an additional DM-RS having dmrs-AdditionalPosition from configuredGrantConfig can be transmitted based on the scheduling type and the PUSCH duration considering whether frequency hopping is enabled.

When the transmitted PUSCH corresponds to a scheduled or configured grant by DCI format 0_1 with a CRC scrambled by C-RNTI, CS-RNTI or MCS-RNTI,

- The terminal can be configured with the upper layer parameter dmrs-Type in DMRS-UplinkConfig, and the configured DM-RS configuration type is used for PUSCH transmission.

- The terminal can set the maximum number of front-loaded DM-RS symbols for PUSCH by the upper layer parameter maxLength in DMRS-UplinkConfig.

When a terminal transmitting a PUSCH sets the upper layer parameter phaseTrackingRS in DMRS-UplinkConfig, the terminal can assume that the following settings do not occur simultaneously for the transmitted PUSCH.

- For DM-RS configuration type 1 and type 2, any DM-RS port among 4-7 or 6-11 is scheduled for each UE, and PT-RS is transmitted from the UE.

For PUSCH scheduled by DCI format 0_1, by activated DCI format 0_1 with CRC scrambled by CS-RNTI or by configured grant type 1 configuration, the UE assumes that the DM-RS CDM group is not used for data transmission.

PTRS (Phase Tracking Reference Signal)

In the 5G NR standard, Phase-tracking reference signal (PTRS) is introduced to compensate for impairment caused by phase noise in high-frequency bands, as phase noise causes common phase error (CPE) and inter-carrier interference (ICI) in the frequency domain.

Below, the operations related to DL PTRS and UL PTRS are described in detail.

DL PTRS related actions

Below, an example of the DL PTRS procedure is described in detail.

The base station transmits PTRS configuration information to the terminal. The PTRS configuration information may refer to PTRS-DownlinkConfig IE. The PTRS-DownlinkConfig IE may include a frequencyDensity parameter, a timeDensity parameter, an epre-Ratio parameter, a resourceElementOffset parameter, etc.

The above frequencyDensity parameter is a parameter indicating the presence and frequency density of DL PTRS as a function of scheduled BW. The above timeDensity parameter is a parameter indicating the presence and time density of DL PTRS as a function of MCS (modulation and coding scheme). The above epre-Ratio parameter is a parameter indicating EPRE (Energy Per Resource Element) between PTRS and PDSCH.

The above base station generates a sequence used for PTRS. The sequence for PTRS is generated using a DMRS sequence of the same subcarrier as shown in Equation 3 below. Sequence generation for PTRS can be defined differently depending on whether transform precoding is enabled, and Equation 3 below shows an example when transform precoding is disabled.

는 위치

및 서브캐리어

에서 주어진 DMRS이다.Here,

is the location

and subcarriers

is the DMRS given in .

That is, the sequence of PTRS uses the sequence of DMRS, but more specifically, the sequence of PTRS in subcarrier k is identical to the sequence of DMRS in subcarrier k.

The base station maps the generated sequence to a resource element, where a resource element may have a meaning including at least one of time, frequency, antenna port, or code.

The position of PTRS in the time domain is mapped to a specific symbol interval starting from the start symbol of PDSCH allocation, and if a DMRS symbol exists, mapping is performed from the symbol following the DMRS symbol. The specific symbol interval may be 1, 2, or 4 symbols.

And, with respect to resource element mapping of PTRS, the frequency location of PTRS is determined by the frequency location of the associated DMRS port and the upper layer parameter UL-PTRS-RE-offset. Here, UL-PTRS-RE-offset is included in the PTRS configuration and indicates the subcarrier offset for UL PTRS for CP-OFDM.

For DL, a PTRS port is associated with the DMRS port with the lowest index among the scheduled DMRS ports. And, for UL, the base station configures which DMRS port is associated with a PTRS port through UL DCI.

The base station transmits the PTRS to the terminal on the above resource elements.

UL PTRS related actions

UL PTRS related operations are similar to DL PTRS related operations discussed above, and the names of parameters related to DL PTRS can be replaced with the names of parameters related to UL PTRS. That is, PTRS-DownlinkConfig IE can be replaced with PTRS-UplinkConfig IE, and in DL PTRS related operations, the base station can be replaced with the terminal, and the terminal can be replaced with the base station. Similarly, sequence generation for PTRS can be defined differently depending on whether transform precoding is enabled.

Downlink transmission and reception operation

The base station schedules downlink transmissions such as frequency/time resources, transmission layers, downlink precoder, MCS, etc. In particular, the base station can determine a beam for PDSCH transmission to the terminal through beam management operations.

And, the terminal receives downlink control information (DCI: Downlink Control Information) for downlink scheduling (i.e., including scheduling information of PDSCH) from the base station on the PDCCH. DCI format 1_0 or 1_1 may be used for downlink scheduling, and in particular, DCI format 1_1 includes the following information: DCI format identifier (Identifier for DCI formats), bandwidth part indicator, frequency domain resource assignment, time domain resource assignment, PRB bundling size indicator, rate matching indicator, ZP CSI-RS trigger, antenna port(s), transmission configuration indication (TCI: Transmission configuration indication), SRS request, DMRS (Demodulation Reference Signal) sequence initialization.

In particular, depending on each state/index indicated in the Antenna port(s) field, the number of DMRS ports can be scheduled, and also single-user (SU)/multi-user (MU) transmission scheduling is possible. Specifically, the order of DMRS ports corresponding to the number of CWs can be predefined according to dmrs-type and maxLength, and the number and/or order of DMRS ports can be indicated through the antenna port field of DCI.

In addition, the TCI field consists of 3 bits, and QCL for DMRS is dynamically indicated by indicating up to 8 TCI states according to the TCI field value. Then, the terminal receives downlink data from the base station on the PDSCH. When the terminal detects a PDCCH including DCI format 1_0 or 1_1, it decodes the PDSCH according to the indication by the corresponding DCI.

Here, when the terminal receives a PDSCH scheduled by DCI format 1_1, the terminal can set a DMRS configuration type by a higher layer parameter 'dmrs-Type', and the DMRS configuration type is used to receive the PDSCH. In addition, the terminal can set a maximum number of front-loaded DMRS symbols for the PDSCH by a higher layer parameter 'maxLength'.

For DMRS configuration type 1, if the terminal is scheduled for a single codeword and is assigned an antenna port mapped to an index of {2, 9, 10, 11, or 30}, or if the terminal is scheduled for two codewords, the terminal assumes that all remaining orthogonal antenna ports are not associated with PDSCH transmissions to another terminal. Alternatively, for DMRS configuration type 2, if the terminal is scheduled for a single codeword and is assigned an antenna port mapped to an index of {2, 10, or 23}, or if the terminal is scheduled for two codewords, the terminal assumes that all remaining orthogonal antenna ports are not associated with PDSCH transmissions to another terminal.

Uplink transmission and reception operation

Figure 1 is a diagram showing an example of uplink transmission and reception operation.

Referring to Fig. 1, the base station schedules uplink transmission such as frequency/time resources, transmission layers, uplink precoder, MCS, etc. (S110). In particular, the base station can determine a beam for PUSCH transmission by the terminal through beam management operations. Then, the terminal receives DCI for uplink scheduling (i.e., including scheduling information of PUSCH) from the base station on the PDCCH (S120). For uplink scheduling, DCI format 0_0 or 0_1 may be used, and in particular, DCI format 0_1 includes the following information: Identifier for DCI formats, UL/SUL (Supplementary uplink) indicator, UL/SUL indicator, Bandwidth part indicator, Frequency domain resource assignment, Time domain resource assignment, Frequency hopping flag, Modulation and coding scheme (MCS), SRS resource indicator (SRI), Precoding information and number of layers, Antenna port(s), SRS request, DMRS sequence initialization, UL-SCH (Uplink Shared Channel) indicator.

In particular, SRS resources set within the SRS resource set associated with the upper layer parameter 'usage' can be indicated by the SRS resource indicator field. In addition, 'spatialRelationInfo' can be set for each SRS resource, and its value can be one of {CRI, SSB, SRI}.

And, the terminal transmits uplink data to the base station on the PUSCH (S130). When the terminal detects a PDCCH including DCI format 0_0 or 0_1, it transmits the corresponding PUSCH according to the instructions of the corresponding DCI. For PUSCH transmission, two transmission methods are supported: codebook-based transmission and non-codebook-based transmission.

For codebook-based transmission, when the upper layer parameter 'txConfig' is set to 'codebook', the terminal is configured for codebook-based transmission. On the other hand, when the upper layer parameter 'txConfig' is set to 'nonCodebook', the terminal is configured for non-codebook based transmission. If the upper layer parameter 'txConfig' is not set, the terminal does not expect to be scheduled by DCI format 0_1. When PUSCH is scheduled by DCI format 0_0, PUSCH transmission is based on a single antenna port. For codebook-based transmission, PUSCH can be scheduled by DCI format 0_0, DCI format 0_1 or semi-statically. When this PUSCH is scheduled by DCI format 0_1, the UE determines a PUSCH transmission precoder based on the SRI, the Transmit Precoding Matrix Indicator (TPMI) and the transmission rank from the DCI, as given by the SRS resource indicator field and the Precoding information and number of layers field. The TPMI is used to indicate a precoder to be applied across antenna ports and corresponds to an SRS resource selected by the SRI when multiple SRS resources are configured. Or, when a single SRS resource is configured, the TPMI is used to indicate a precoder to be applied across antenna ports and corresponds to the single SRS resource. A transmission precoder is selected from an uplink codebook having the same number of antenna ports as the upper layer parameter 'nrofSRS-Ports'. When the upper layer in which the UE is set to 'codebook' is configured with the parameter 'txConfig', the UE is configured with at least one SRS resource. The SRI indicated in slot n is associated with the most recent transmission of the SRS resource identified by the SRI, where the SRS resource precedes the PDCCH carrying the SRI (i.e., slot n).

For non-codebook based transmission, PUSCH can be scheduled in DCI format 0_0, DCI format 0_1 or semi-statically. When multiple SRS resources are configured, the UE can determine the PUSCH precoder and transmission rank based on the wideband SRS, where the SRI is given by the SRS resource indicator in the DCI or the higher layer parameter 'srs-ResourceIndicator'. The UE uses one or multiple SRS resources for SRS transmission, where the number of SRS resources can be configured for simultaneous transmission within the same RB based on the UE capability. Only one SRS port is configured for each SRS resource. Only one SRS resource can be configured with the higher layer parameter 'usage' set to 'nonCodebook'. The maximum number of SRS resources that can be configured for non-codebook based uplink transmission is 4. The SRI indicated in slot n is associated with the most recent transmission of the SRS resource identified by the SRI, where the SRS transmission precedes the PDCCH carrying the SRI (i.e., slot n).

Description of STxMP (Simultaneous Transmission across Multi-panels)

In R18, a method for a UE to simultaneously transmit multiple channels/RS of the same type or multiple channels/RS of different types is discussed. In the case of a conventional UE, the operation of transmitting multiple channels/RS at a time is restricted (e.g., it is possible to simultaneously transmit multiple SRS resources of different SRS sets for UL beam measurement, but it is impossible to simultaneously transmit multiple PUSCHs). However, advanced UEs in the future may ease this restriction and transmit multiple channels or RSs simultaneously using multiple transmission panels. Such a UE is called an STxMP UE. For example, two PUSCHs corresponding to two UL TBs are scheduled on the same RE, and Spatial relation RS 1 and PC parameter Set 1 (i.e., UL TCI state 1) and Spatial relation RS 2 and PC parameter Set 2 (i.e., UL TCI state 2) are set for PUSCH 1 and 2 transmission, respectively. The UE transmits PUSCH 1 using panel 1 corresponding to UL TCI state 1 and simultaneously transmits PUSCH 2 using panel 2 corresponding to UL TCI state 2.

When the base station schedules PUSCH through DCI, it can indicate whether the PUSCH will be transmitted as STxMP, single panel, or MTRP PUSCH repetition. Of course, the UE must have STxMP capability, and the STxMP mode must be enabled in advance through RRC signaling, etc. To this end, the existing SRS resource set indication field can be redefined and used, or a new DCI field can be introduced.

There are two methods being considered for the R18 STxMP transmission technique: SFN and SDM.

The SFN method is a method of transmitting the same channel as the one transmitted from one panel to another panel. However, since the UL channels of each panel are different, they are transmitted with different precoders, different transmission powers, and different transmission beams (i.e., spatial relation RS indicated by UL TCI) for each panel.

The SDM method is a method that can be transmitted from rank 2 and above, and it is a method in which panel 1 transmits some of the multi-layers and panel 2 transmits the remaining layers. For example, in 2-layer transmission, panel 1 transmits the 1st layer and panel 2 transmits the 2nd layer. Even in this case, since the UL channels of each panel are different, different precoder, different transmission power, and different transmission beam (i.e., spatial relation RS indicated by UL TCI) are transmitted for each panel.

Panel is not a term used in the standard, and other resources/terms corresponding to panel are used. For example, different panels can be mapped to and used for different SRS resource sets or SRS resources. For example, the first panel is mapped to SRS resource set 0, the second panel is mapped to SRS resource set 1, and the SRS resources of SRS resource set 0 can mean the transmission antenna port of the first panel, and the SRS resources of SRS resource set 1 can mean the transmission antenna port of the second panel.

Description of the Unified TCI framework

In R17, not only the DL TCI state but also the UL TCI state can be indicated through DL DCI (e.g. DCI format 1-1 or 1-2) or only the UL TCI state can be indicated without indicating the DL TCI state. Accordingly, the methods used in the existing R15/R16 to set the UL beam and power control (PC) are replaced in R17 with the above UL TCI state indication method. More specifically, in R17, one UL TCI state can be indicated through the TCI field of DL DCI, and the corresponding UL TCI state is applied to all PUSCHs and all PUCCHs after a certain time called beam application time, and can be applied to some or all of the indicated SRS resource sets. In R18, a method in which multiple UL TCI states (and/or DL TCI states) are indicated through the TCI field of DL DCI is under discussion.

AIML related explanation

With the advancement of AI/ML (Artificial intelligence/machine learning) technology, the node(s) and terminal(s) that make up the wireless communication network are becoming more intelligent/advanced. In particular, with the intelligence of the network/base station, it is expected that various network/base station decision parameter values (e.g., transmission/reception power of each base station, transmission power of each terminal, precoder/beam of base station/terminal, time/frequency resource allocation for each terminal, duplex method of each base station, etc.) can be quickly optimized and derived/applied according to various environmental parameters (e.g., distribution/location of base stations, distribution/location/material of buildings/furniture, etc., location/movement direction/speed of terminals, climate information, etc.).

The contents examined above (DMRS, PTRS, UL transmission/reception operation, AI/ML, etc.) can be applied in combination with the methods proposed in this specification, which will be described later, or can be supplemented to clarify the technical characteristics of the methods proposed in this specification. The methods described below are distinguished only for the convenience of explanation, and it goes without saying that some components of one method can be replaced with some components of another method, or can be applied in combination with each other.

In this specification, 'port' and 'antenna port' can be interpreted as having the same meaning. For example, PTRS (DMRS) port means PTRS (DMRS) antenna port, and vice versa can be interpreted equally.

In this specification, 'DMRS (or PTRS)' may mean 'DM-RS (or PT-RS)' and vice versa.

3Tx can be applied for UL PUSCH transmission in NR MIMO Rel19 or later standards. According to the existing standards, 1/2/4/8 Tx uplink transmission is supported. In order to support 3 Tx uplink transmission introduced in Rel 19 as shown in the WID below, a method for PTRS-DMRS association is required.

“Specify non-coherent UL codebook to facilitate 3-antenna-port codebook-based transmissions, without enhancement on UL full power transmission and without enhancement on SRS resource

Note: UL full power transmission mode 1 and 2 are not supported.”

To support 3 Tx UL, a method and device for PTRS-DMRS association are proposed as follows.

The proposed method is explained based on the UE PTRS transmission procedure, but can be applied to the PTRS reception procedure in the same way. However, in the PTRS transmission procedure, the PTRS-DMRS association can be determined by Rank indicated by SRI or PMI.

Below, we describe in detail the existing operations related to PTRS-DMRS association.

DMRS type 1 has a total of 8 ports, ports 0 to 8, for 1 FL symbol. When the maximum number of PTRS ports is set to 1, PTRS-DMRS association can be performed based on a 2-bit table. This example can be applied to a case where two codewords are scheduled for a terminal. Specifically, a PTRS port can be associated with one of the 1st to 8th scheduled DMRS ports indicated based on a 2-bit PTRS-DMRS association field of DCI for a codeword having a Higher MCS.

When the maximum number of PTRS ports is set to 2, PTRS-DMRS association can be performed based on a 4-bit table. For example, the value of the MSB 2 bit of the PTRS-DMRS association field indicates one of the 1st to 4th DMRS ports sharing PTRS port 0. The value of the LSB 2 bit of the PTRS-DMRS association field indicates one of the 1st to 4th DMRS ports sharing PTRS port 1.

For NCB PUSCH case, the 1st to 4th DMRS ports sharing PTRS port 0 can be identified by the PTRS port index=0 set in the SRS resource indicated by SRI. The 1st to 4th DMRS ports sharing PTRS port 1 can be identified in the same way.

For 1 CW (one codeword) of CB PUSCH case, DMRS ports corresponding to layers using PUSCH antenna ports 1000 and 1002 share PTRS 0, and DMRS ports corresponding to layers using PUSCH antenna ports 1001 and 1003 share PTRS 1. And for 2 CW (two codewords), DMRS ports corresponding to layers using PUSCH antenna ports 1000, 1001, 1004, and 1005 share PTRS 0, and DMRS ports corresponding to layers using PUSCH antenna ports 1002, 1003, 1006, and 1007 share PTRS 1.

The behavior according to the existing standards is as follows:

For non-codebook based UL transmission, the actual number of UL PT-RS ports to be transmitted is determined based on the SRI in DCI format 0_1, 0_2 or 0_3 or the higher layer parameter sri-ResourceIndicator in rrc-ConfiguredUplinkGrant. When two SRS resource sets are configured in srs-ResourceSetToAddModList or srs-ResourceSetToAddModListDCI-0-2 and the higher layer parameter usage of SRS-ResourceSet is set to 'noncodebook', the actual number of UL PT-RS ports to be transmitted for each SRS resource set is determined based on the SRI corresponding to the associated SRS resource set or the higher layer parameter sri-ResourceIndicator or sri-ResourceIndicator2 in rrc-ConfiguredUplinkGrant. When the upper layer parameter phaseTrackingRS in DMRS-UplinkConfig is set in the UE, the PT-RS port index for each configured SRS resource by the upper layer parameter ptrs-PortIndex set by SRS-Config is set in the UE. If the PT-RS port index associated with another SRI is the same, the corresponding UL DM-RS port is associated with one UL PT-RS port ( For non-codebook based UL transmission, the actual number of UL PT-RS port(s) to transmit is determined based on SRI(s) in DCI format 0_1, 0_2 or 0_3 or higher layer parameter sri-ResourceIndicator in rrc-ConfiguredUplinkGrant . When two SRS resource sets are configured in srs-ResourceSetToAddModList or srs-ResourceSetToAddModListDCI-0-2 with higher layer parameter usage in SRS-ResourceSet set to 'noncodebook', the actual number of UL PT-RS port(s) to transmit corresponding to each SRS resource set is determined based on SRI(s) corresponding to the associated SRS resource set or higher layer parameter sri-ResourceIndicator or sri-ResourceIndicator2 corresponding to the associated SRS resource set in rrc-ConfiguredUplinkGrant . A UE is configured with the PT-RS port index for each configured SRS resource by the higher layer parameter ptrs-PortIndex configured by SRS-Config if the UE is configured with the higher layer parameter phaseTrackingRS in DMRS-UplinkConfig . If the PT-RS port index associated with different SRIs are the same, the corresponding UL DM-RS ports are associated to the one UL PT-RS port).

When the higher layer parameter multipanelScheme is set to 'sdmscheme' and two SRS resource sets are configured in srs-ResourceSetToAddModList or srs-ResourceSetToAddModListDCI-0-2 with higher layer parameter usage in SRS-ResourceSet set to 'codebook'/'nonCodebook' and higher layer parameter maxNrofPortsforSDM in PTRS-UplinkConfig set to n2 , the actual number of UL PT-RS ports to be transmitted corresponding to the SRS resource set is 2. n2, the actual number of UL PT-RS port(s) to transmit corresponding to SRS resource sets is 2 ).

When the higher layer parameter multipanelScheme is set to 'SFNscheme' and two SRS resource sets are configured in srs-ResourceSetToAddModList or srs-ResourceSetToAddModListDCI-0-2 with higher layer parameter usage in SRS-ResourceSet set to 'codebook'/'nonCodebook' and the higher layer parameter maxNrofPorts in PTRS-UplinkConfig is set to n2 , the actual number of UL PT-RS ports to be transmitted for each SRS resource set is determined by the 1st TPMI Codepoint field for ' codebook' or the 1st SRI(s) Codepoint field for ' nonCodebook '. 'codebook'/'nonCodebook' and the higher layer parameter maxNrofPorts in PTRS-UplinkConfig is set to n2 , the actual number of UL PT-RS port(s) to transmit corresponding to each SRS resource set is determined based on 1st TPMI codepoint field for 'codebook' or 1 ^st SRI(s) codepoint field for 'nonCodebook').

For partial-coherent and non-coherent codebook-based UL transmission, the actual number of UL PT-RS port(s) is determined based on TPMI(s) and/or number of layers which are indicated by ' Precoding information and number of layers' field(s) in DCI format 0_1, 0_2 or 0_3 or configured by higher layer parameter precodingAndNumberOfLayers .

- if the UE is configured with the higher layer parameter maxNrofPorts in PTRS-UplinkConfig set to 'n2', the actual UL PT- RS port (s) and the associated transmission layer(s) are derived from indicated TPMI(s) as:.

- PUSCH antenna ports 1000 and 1002 in indicated TPMI(s) share PT-RS port 0, and PUSCH antenna ports 1001 and 1003 in indicated TPMI(s) share PT-RS port 1.

- UL PT-RS port 0 is associated with UL layer 'x' among the layers transmitted to PUSCH antenna port 1000 and PUSCH antenna port 1002 in the indicated TPMI(s), and UL PT-RS port 1 is associated with UL layer 'y' among the layers transmitted to PUSCH antenna port 1001 and PUSCH antenna port 1003 in the indicated TPMI(s). Wherein 'x' and/or 'y' are given by DCI parameter 'PTRS-DMRS association' as shown in DCI format 0_1 , 0_2 and 0_3 described in Clause 7.3.1 of [5, TS38.212].

If a UE is scheduled with two codewords,

- When the upper layer parameter maxNrofPorts of PTRS-UplinkConfig in the UE is set to 'n1', the PT-RS port is associated with one of the DM-RS ports indicated by the DCI field PTRS-DMRS ASSOCIATION for a codeword with a higher MCS. If the MCS indices of two codewords are the same, the PT-RS antenna port is associated with codeword 0. When a codeword is scheduled to transmit PUSCH for retransmission, the MCS for determining PT-RS association to codeword is obtained from the DCI for the same transport block in the initial transmission (- if the UE is configured with the higher layer parameter maxNrofPorts in PTRS-UplinkConfig set to 'n1', the PT-RS port is associated with the one of DM-RS ports indicated by DCI field PTRS-DMRS association for the codeword with the higher MCS. If the MCS indices of the two codewords are the same, the PT-RS antenna port is associated with codeword 0. When a codeword is scheduled to transmit PUSCH for retransmission, the MCS for determining PT-RS association to codeword is obtained from the DCI for the same transport block in the initial transmission).

- When the upper layer parameter maxNrofPorts of PTRS-UplinkConfig in the UE is set to 'n2', each PT-RS port is associated with one of the DM-RS ports indicated by the DCI field PTRS-DMRS Association. PUSCH antenna ports 1000, 1001, 1004 and 1005 share PT-RS port 0, and PUSCH antenna ports 1002, 1003, 1006 and 1007 share PT-RS port 1 (- if the UE is configured with the higher layer parameter maxNrofPorts in PTRS-UplinkConfig set to 'n2', each PT-RS port is associated with the one of DM-RS ports indicated by DCI field PTRS-DMRS association. PUSCH antenna ports 1000, 1001, 1004 and 1005 share PT-RS port 0, and PUSCH antenna ports 1002, 1003, 1006 and 1007 share PT-RS port 1).

Technical issues to be resolved

According to the Rel-18 standard, the maximum number of PTRS ports is set to 2 (when the rank is greater than 4), and PTRS-DMRS association is indicated based on a 4-bit table in 4 Tx partial coherent transmission. Specifically, the value of the MSB 2 bits of the 4-bit PTRS-DMRS association field indicates one of the 1st to 4th DMRS ports sharing PTRS port 0. The 1st to 4th DMRS ports sharing PTRS port 0 can be associated with PUSCH antenna ports 1000, 1001, 1004, and 1005 sharing PTRS port 0. The value of the LSB 2 bits of the 4-bit PTRS-DMRS association field indicates one of the 1st to 4th DMRS ports sharing PTRS port 1. The 1st to 4th DMRS ports sharing PTRS port 1 can be associated with PUSCH antenna ports 1002, 1003, 1006, and 1007 sharing PTRS port 1.

In the case of 3 Tx Partial coherent transmission, it can be assumed that only 2 ports are capable of coherent transmission. In a port configuration of 2+1 or 1+2, only 2 ports may be capable of coherent transmission. For example, the configuration method of the 3Tx Partial coherent codebook as shown in Table 3 below can be considered.

Table 3 illustrates a 2+1 port mapping codebook (Precoding Matrix). Table 4 below illustrates a 1+2 port mapping codebook.

In Table 4, each of x and y can be one of {1, j, -1, -j}. For codebook flexibility, the alphabet size can be set/indicated by the base station.

The 2+1 and 1+2 port mapping orders are agreed upon in advance, and one of the two codebooks can be set/instructed to the terminal based on the codebook configuration or the terminal's capability report.

In case that only 2 ports are capable of coherent transmission in 3 Tx Partial coherent transmission, a PTRS-DMRS association indication method should be considered. More specifically, a method for PTRS-DMRS association needs to be defined for the cases where 2 PTRS ports are configured/indicated and 1 PTRS port is configured/indicated during PUSCH transmission of a 3Tx terminal.

For convenience of explanation, the following embodiments assume that only two of the three ports are capable of coherent transmission, but this is not intended to limit the scope of application of the embodiments of the present specification. The embodiments described below can be applied to codebook-based uplink transmission based on three ports.

Method 1-1

In 3 Tx partial coherent transmission, when the (maximum) number of PTRS ports is set to 2, 1-bit DCI field for PTRS-DMRS association is required for 2 ports (e.g., antenna port 1000, 1001 or antenna port 1000, 1002). 1-bit DCI field for PTRS-DMRS association is not required for the remaining 1 port (e.g., antenna port 1002 or antenna port 1001).

The terminal does not expect different PTRS port combinations to be indicated for each DMRS port in the 3 Tx.

For example, in the case of 2+1 mapping of the CB PUSCH case in Table 3, the DMRS ports corresponding to the layers using PUSCH antenna ports 1000 and/or 1001, which are non-zero elements in the codebook, share PTRS pot 0. Here, the layers using PUSCH antenna ports 1000 and/or 1001 may mean layers to which a precoder having non-zero first and/or second rows in the precoding matrix of the codebook is applied. The DMRS ports corresponding to the layer using PUSCH antenna port 1002 share the remaining PTRS port 1. Here, the layer using PUSCH antenna port 1002 may mean layers to which a precoder having non-zero third rows in the precoding matrix of the codebook is applied.

For example, in the case of 1+2 mapping of the CB PUSCH case in Table 4, the DMRS port corresponding to the layer using PUSCH antenna port 1000, which is a non-zero element in the codebook, shares PTRS 0. Here, the layer using PUSCH antenna port 1000 may mean a layer to which a precoder having a non-zero first row in the precoding matrix of the codebook is applied. The DMRS port corresponding to the layer using PUSCH antenna port 1001 and/or 1002 shares the remaining PTRS 1 port. Here, the layer using PUSCH antenna port 1001 and/or 1002 may mean a layer to which a precoder having a non-zero second and/or third row in the precoding matrix of the codebook is applied.

However, the above examples are described on the assumption that the two coherent ports are PUSCH antenna ports 1000, 1001 (or PUSCH antenna ports 1001, 1002) associated with the first row and the second row (or the second row and the third row) of a codebook (or precoding matrix). This is an example for convenience of explanation and the technical idea of the present embodiment is not intended to be limited to the example. As a specific example, the present embodiment can also be applied to PUSCH antenna ports 1000, 1002, where the two coherent ports are associated with the first row and the third row of a codebook (or precoding matrix). In this case, PUSCH antenna ports 1000, 1002 share PTRS port 0. One of the two DMRS ports sharing PTRS port 0 can be indicated based on a 1-bit PTRS-DMRS association field. The above two DMRS ports may be associated with PUSCH antenna ports 1000, 1002. More specifically, the above two DMRS ports may be associated with layers transmitted based on PUSCH antenna ports 1000, 1002. The remaining one port (PUSCH antenna port 1001) may be associated with PTRS port 1.

According to this embodiment, the following effects are achieved. (coherent) 2 ports require a 1-bit DCI field, but the remaining 1 port does not require a DCI field. The existing number of bits (2 bits) of DCI fields for PTRS-DMRS association is reduced by 1 bit.

Method 1-2

In 3 Tx partial coherent transmission, when the (maximum) number of PTRS ports is set to 2, one PTRS port can be associated with a DMRS port based on a specific DMRS port index (e.g., lower/higher DMRS port index) among the coherent 2 DMRS ports, and the remaining one PTRS port can be associated with the remaining one DMRS port. For example, in the case of 2+1 mapping of CB PUSCH case, it can be assumed that only 2 ports among 3 DMRS ports are capable of coherent transmission. PTRS port 0 can be associated with a specific DMRS port index (e.g., lower/higher DMRS port index) among the 2 ports, and PTRS port 1 can be associated with the remaining one DMRS port. As described above, PTRS-DMRS association can be defined/configured without DCI field. DCI field is not required for PTRS-DMRS association in 3 Tx. Therefore, compared to the existing method, the DCI overhead can be reduced by the number of bits of the PTRS-DMRS association field.

Method 2-1

In case the (maximum) number of PTRS ports is set to 1 port in 3 Tx Partial coherent transmission, PTRS-DMRS association can be indicated only for 2 ports among 3 DMRS ports capable of coherent transmission. For example, in case of 2+1 mapping of CB PUSCH case in Table 3, PTRS can be mapped to only one port among 2 DMRS ports corresponding to the layer using PUSCH antenna port 1000 and/or 1001 capable of coherent transmission. The layer using PUSCH antenna port 1000 and/or 1001 may mean a layer to which a precoder having non-zero first and/or second row in the precoding matrix of the codebook is applied. PTRS mapping may not be allowed for one DMRS port corresponding to the layer using the remaining PUSCH antenna port 1002.

In this case, the remaining one DMRS port is difficult to use because it cannot estimate phase error, but the two DMRS ports to which PTRS-DMRS association is directed can be used because phase error estimation is possible. When two PTRS ports are required but the terminal supports only one PTRS port, configuring PTRS on two coherent ports is more advantageous in securing phase estimation and performance than configuring PTRS on the remaining one port. For example, coherent 2 ports are more likely to have the same phase noise source (e.g. panel, amplifier, etc.). Therefore, when only 1 PTRS port needs to be transmitted, it is more advantageous to map the PTRS port in the direction of utilizing the 2 Tx with more similar phase noise properties among the 3 Tx (even if the remaining 1 Tx is ignored).

In the conventional method, a 2-bit DCI field is required to indicate a PTRS-DMRS association related to one DMRS port among three layers. According to the present embodiment, the number of bits of the DCI field for indicating the PTRS-DMRS association is reduced from 2 bits to 1 bit.

Method 2-2

In 3 Tx Partial coherent transmission, when the (maximum) number of PTRS ports is set to 1 port, one of the 2 DMRS ports among the 3 DMRS ports may be indicated based on a 1-bit PTRS-DMRS association field. For example, the 2 DMRS ports may include one port (e.g., lower/higher DMRS port index) selected by a set rule among the 2 ports (capable of coherent transmission) and the remaining 1 port.

For example, in the case of 2+1 mapping of CB PUSCH case, only 2 ports out of 3 DMRS ports can support coherent transmission. Among the 2 ports, a specific DMRS port index (e.g., lower/higher DMRS port index) or the remaining DMRS ports can be indicated as being associated with a PTRS port. In this case, one of the 2 ports capable of coherent transmission or the remaining 1 port can be indicated based on a 1-bit field. If indicated as above, the DCI field for PTRS-DMRS association is reduced from 2 bits to 1 bit.

Method 2-3

In 3 Tx Partial coherent transmission, when the (maximum) number of PTRS ports is set to 1, two ports can be selected from among three DMRS ports according to a set rule, regardless of coherency DMRS port distinction. For example, the lowest DMRS port index and the next DMRS port index can be selected. Among the two DMRS ports, the DMRS port associated with the PTRS port can be indicated based on a 1-bit field. If indicated as above, the DCI field for PTRS-DMRS association is reduced from 2 bits to 1 bit.

The above suggestions can be finally applied through a combination/combination.

In terms of implementation, the operations of the base station/terminal according to the embodiments described above (e.g., operations based on at least one of Method 1-1, Method 1-2, Method 2-1, Method 2-2, and Method 2-3) can be processed by the device (e.g., 100, 200) of FIG. 4 described below.

In addition, the operations of the base station/terminal according to the above-described embodiments (e.g., operations based on at least one of Method 1-1, Method 1-2, Method 2-1, Method 2-2, and Method 2-3) may be stored in a memory (e.g., 140, 240 of FIG. 4) in the form of commands/programs (e.g., instructions, executable codes) for driving at least one processor (e.g., 110, 210 of FIG. 4).

The embodiments described below are specifically described with reference to FIGS. 2 and 3 in terms of the operation of the terminal and the base station. The methods described below are distinguished only for the convenience of explanation, and it goes without saying that some components of one method may be substituted for some components of another method or may be applied in combination with each other.

FIG. 2 is a flowchart illustrating a method according to one embodiment of the present specification.

Referring to FIG. 2, a method according to one embodiment of the present specification includes a DCI receiving step (S210) and a PTRS transmitting step (S220).

In S210, the terminal receives downlink control information (DCI) from the base station. For example, the DCI may be based on a DCI format for scheduling a physical uplink shared channel (PUSCH).

In S220, the terminal transmits a phase tracking reference signal (PTRS) to the base station. For example, the PTRS may be related to the PUSCH.

For example, the DCI may include a PTRS-DMRS association field. An association between PTRS port(s) and DMRS port(s) may be indicated based on the PTRS-DMRS association field.

In one embodiment, the PTRS port(s) associated with the PTRS may be associated with a codebook based UL transmission based on one or more antenna ports. For example, the codebook based UL transmission may be i) a partial-coherent codebook based UL transmission or ii) a non-coherent codebook based UL transmission.

Below, embodiments related to PTRS-DMRS association for supporting 3Tx uplink transmission are specifically described.

In one embodiment, based on the number of the one or more antenna ports being 3 and 2 PTRS ports being configured: the number of bits of the PTRS-DMRS association field may be 1. Based on the PTRS-DMRS association field, one of the two DMRS ports sharing a first PTRS port (e.g., PTRS port 0) may be indicated. The two DMRS ports may be associated with two of the three antenna ports. The second PTRS port (e.g., PTRS port 1) may be associated with the remaining antenna port of the three antenna ports. The present embodiment may be based on Method 1-1 and/or Method 1-2.

For example, the two antenna ports may be antenna ports 1000, 1002 (e.g., PUSCH antenna port 1000, 1002). The remaining antenna port may be antenna port 1001 (e.g., PUSCH antenna port 1001).

As a specific example, PUSCH antenna ports 1000 and 1002 share PTRS port 0, and PUSCH antenna port 1001 is associated with PTRS port 1. The PTRS-DMRS association field (1 bit) may indicate one of the two DMRS ports (1 ^st DMRS port, 2 ^nd DMRS port) sharing PTRS port 0. The PTRS port 0 may be associated with a layer among the layers transmitted based on PUSCH antenna ports 1000 and 1002. The layer may be associated with one of the two DMRS ports (1 ^st DMRS port, 2 ^nd DMRS port) indicated/determined based on the PTRS-DMRS association field (1 bit).

For example, the DCI may include a precoding information and number of layers field. A Transmitted Precoding Matrix Indicator (TPMI) may be indicated based on the precoding information and number of layers field.

For example, the precoding matrix based on the TPMI may include at least one column consisting of three rows. The three rows may be associated with the three antenna ports. As a specific example, the precoding matrix may be one of the matrices according to the Rank (number of layers) of Table 3 (or Table 4). The precoding matrix may be associated with i) partial-coherent codebook based UL transmission or ii) non-coherent codebook based UL transmission.

Below, the precoding matrix for each type of coherent codebook is specifically described.

For fully-coherent codebook-based uplink transmission, all elements of the precoding matrix are non-zero elements.

와 같은 형태를 갖는 행렬일 수 있다. Non-zero element/zero element의 배치와 각 element의 값은 코드북(프리코딩 행렬) 구현 방식에 따라 달라질 수 있다.For partial-coherent codebook-based uplink transmission, the precoding matrix includes at least one element that is 0. For example, the precoding matrix associated with the partial-coherent codebook is

It can be a matrix having the same form as . The arrangement of non-zero elements/zero elements and the values of each element can vary depending on the codebook (precoding matrix) implementation method.

와 같은 형태를 갖는 행렬일 수 있다. Non-zero element의 배치와 해당 element의 값은 코드북(프리코딩 행렬) 구현 방식에 따라 달라질 수 있다.For uplink transmission based on a non-coherent codebook, each column of the precoding matrix has only one non-zero element, and each row of the precoding matrix also has only one non-zero element. As a specific example, a precoding matrix associated with a non-coherent codebook is

It can be a matrix having the same form as . The arrangement of non-zero elements and the values of the corresponding elements can vary depending on the implementation method of the codebook (precoding matrix).

In the above-described precoding matrix, the first row is associated with the first antenna port among three antenna ports (e.g., PUSCH antenna port 1000), the second row is associated with the second antenna port among three antenna ports (e.g., PUSCH antenna port 1001), and the third row is associated with the third antenna port among three antenna ports (e.g., PUSCH antenna port 1002).

In one embodiment, the two antenna ports may refer to two ports among the three antenna ports capable of the above-described coherent transmission. More specifically, the two antenna ports may be PUSCH antenna ports 1000, 1002 associated with a first row and a third row based on non-zero elements of the precoding matrix. Specifically, the two antenna ports may be associated with two elements out of three elements in the at least one column. Each of the two elements may be based on a value other than zero.

In one embodiment, the number of the one or more antenna ports is 4, and based on the two PTRS ports being set, PTRS-DMRS association may be indicated according to a conventional method. Specifically, the number of bits of the PTRS-DMRS association field may be 2. Based on the value of the MSB (Most Significant Bit) of the PTRS-DMRS association field, one of the two first DMRS ports sharing the first PTRS port may be indicated. Based on the value of the LSB (Least Significant Bit) of the PTRS-DMRS association field, one of the two second DMRS ports sharing the second PTRS port may be indicated. The above two first DMRS ports may be associated with two antenna ports (e.g., PUSCH antenna port 1000, 1002) among four antenna ports (e.g., PUSCH antenna port 1000-1003), and the above two second DMRS ports may be associated with the remaining two antenna ports (e.g., PUSCH antenna port 1001, 1003) among the four antenna ports.

In one embodiment, the number of the one or more antenna ports is 8, and based on the two PTRS ports being set, PTRS-DMRS association may be indicated according to a conventional method. Specifically, the number of bits of the PTRS-DMRS association field may be 4. One of the four first DMRS ports sharing the first PTRS port may be indicated based on the values of two MSBs (Most Significant Bits) of the PTRS-DMRS association field. One of the four second DMRS ports sharing the second PTRS port may be indicated based on the values of two LSBs (Least Significant Bits) of the PTRS-DMRS association field. The above four first DMRS ports may be associated with four antenna ports (e.g., PUSCH anntenna ports 1000, 1001, 1004, 1005) among eight antenna ports (e.g., PUSCH antenna ports 1000-1007), and the above four second DMRS ports may be associated with the remaining four antenna ports (e.g., PUSCH anntenna ports 1002, 1003, 1006, 1007) among the eight antenna ports.

In one embodiment, based on the number of the one or more antenna ports being 3 and one PTRS port being configured: the number of bits of the PTRS-DMRS association field may be 1. Based on the PTRS-DMRS association field, one of the two DMRS ports sharing the one PTRS port may be indicated. The present embodiment may be based on at least one of Methods 2-1 to 2-3.

For example, the two DMRS ports may be associated with specific two antenna ports among the three antenna ports.

For example, the above-mentioned two specific antenna ports may be related to partial-coherent codebook based UL transmission. The present embodiment may be based on Method 2-1.

For example, the specific two antenna ports may include i) one port determined from among two ports associated with partial-coherent codebook based UL transmission and ii) one port remaining from among the three ports except the two ports. The present embodiment may be based on Method 2-2.

For example, the two specific antenna ports may be determined based on the order of the antenna port index among the three ports. The present embodiment may be based on Method 2-3.

The operations based on S210 to S220 described above can be implemented by the device of Fig. 4. For example, the terminal (200) can control one or more transceivers (230) and/or one or more memories (240) to perform the operations based on S210 to S220.

The embodiments described below are specifically described in terms of base station operation.

S310 to S320 described below correspond to S210 to S220 described in FIG. 2. Considering the above correspondence, redundant descriptions are omitted. That is, specific descriptions of base station operations described below may be replaced with descriptions/embodiments of FIG. 2 corresponding to the corresponding operations. For example, descriptions/embodiments of S210 to S220 of FIG. 2 may be additionally applied to base station operations of S310 to S320 described below.

FIG. 3 is a flowchart illustrating a method according to another embodiment of the present specification.

Referring to FIG. 3, a method according to another embodiment of the present specification includes a DCI transmission step (S310) and a PTRS reception step (S320).

In S310, the base station transmits downlink control information (DCI) to the terminal.

In S320, the base station receives a phase tracking reference signal (PTRS) from the terminal.

For example, the DCI may include a PTRS-DMRS association field.

For example, the PTRS port(s) associated with the PTRS may be associated with codebook based UL transmission based on one or more antenna ports.

In one embodiment, based on the number of the one or more antenna ports being 3 and 2 PTRS ports being configured: the number of bits of the PTRS-DMRS association field may be 1. Based on the PTRS-DMRS association field, one of the two DMRS ports sharing a first PTRS port (e.g., PTRS port 0) may be indicated. The two DMRS ports may be associated with two of the three antenna ports. The second PTRS port (e.g., PTRS port 1) may be associated with the remaining antenna port of the three antenna ports. The present embodiment may be based on Method 1-1 and/or Method 1-2.

The operations based on S310 to S320 described above can be implemented by the device of Fig. 4. For example, the base station (100) can control one or more transceivers (130) and/or one or more memories (140) to perform the operations based on S310 to S320.

The operations/terms based on the embodiments described above have been described assuming a 5G system. However, this is for the convenience of explanation and is not intended to limit the scope of application of the technical problems and problem-solving means to be solved by this specification to a specific system. That is, the technical problems/technical issues/problems mentioned in this specification may equally exist in other systems (e.g., 6G systems). It is obvious that the embodiments of this specification may be extended and applied to solve problems equally existing in the other systems. Therefore, for the extended application of the embodiments of this specification to other systems, the terms defined/described based on the 5G system may be replaced/changed with terms defined in the other systems (or generalized terms not specific to one system). For example, PRACH, PUSCH, PUCCH or SRS may be replaced/changed with uplink signals (or uplink channels). For example, SSB, CSI-RS, PDSCH, PDCCH may be replaced/changed with downlink signals (or downlink channels).

Below, a device to which an embodiment of the present specification can be applied (a device that implements a method/operation according to an embodiment of the present specification) is described with reference to FIG. 4.

FIG. 4 is a drawing showing the configuration of a first device and a second device according to an embodiment of the present specification.

The first device (100) may include a processor (110), an antenna unit (120), a transceiver (130), and a memory (140).

The processor (110) performs baseband-related signal processing and may include an upper layer processing unit (111) and a physical layer processing unit (115). The upper layer processing unit (111) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (115) may process operations of a PHY layer. For example, when the first device (100) is a base station device in base station-terminal communication, the physical layer processing unit (115) may perform uplink reception signal processing, downlink transmission signal processing, etc. For example, when the first device (100) is a first terminal device in terminal-to-terminal communication, the physical layer processing unit (115) may perform downlink reception signal processing, uplink transmission signal processing, sidelink transmission signal processing, etc. In addition to performing baseband-related signal processing, the processor (110) may also control the overall operation of the first device (100).

The antenna unit (120) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (130) may include an RF (Radio Frequency) transmitter and an RF receiver. The memory (140) may store information processed by the processor (110), and software, an operating system, applications, etc. related to the operation of the first device (100), and may also include components such as a buffer.

The processor (110) of the first device (100) may be configured to implement operations of the base station in base station-to-terminal communication (or operations of the first terminal device in terminal-to-terminal communication) in the embodiments described in the present disclosure.

The second device (200) may include a processor (210), an antenna unit (220), a transceiver (230), and a memory (240).

The processor (210) performs baseband-related signal processing and may include an upper layer processing unit (211) and a physical layer processing unit (215). The upper layer processing unit (211) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (215) may process operations of a PHY layer. For example, when the second device (200) is a terminal device in base station-terminal communication, the physical layer processing unit (215) may perform downlink reception signal processing, uplink transmission signal processing, etc. For example, when the second device (200) is a second terminal device in terminal-to-terminal communication, the physical layer processing unit (215) may perform downlink reception signal processing, uplink transmission signal processing, sidelink reception signal processing, etc. In addition to performing baseband-related signal processing, the processor (210) may also control the overall operation of the second device (210).

The antenna unit (220) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (230) may include an RF transmitter and an RF receiver. The memory (240) may store information processed by the processor (210), and software, an operating system, applications, etc. related to the operation of the second device (200), and may also include components such as a buffer.

The processor (210) of the second device (200) may be configured to implement operations of a terminal in base station-to-terminal communication (or operations of a second terminal device in terminal-to-terminal communication) in the embodiments described in the present disclosure.

In the operation of the first device (100) and the second device (200), the matters described for the base station and the terminal (or the first terminal and the second terminal in the terminal-to-terminal communication) in the examples of the present disclosure can be applied equally, and redundant descriptions are omitted.

Here, the wireless communication technology implemented in the device (100, 200) of the present disclosure may include LTE, NR, and 6G, as well as Narrowband Internet of Things (NB-IoT) for low-power communication. For example, the NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and/or LTE Cat NB2, and is not limited to the above-described names.

Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure may perform communication based on LTE-M technology. For example, the LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, the LTE-M technology may be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) LTE M, and is not limited to the above-described names.

Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure may include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create PAN (personal area networks) related to small/low-power digital communication based on various standards such as IEEE 802.15.4, and may be called by various names.

Claims (18)

In terms of method, A step of receiving downlink control information (DCI) from a base station; and A step of transmitting a phase tracking reference signal (PTRS) to the base station; Including, The above DCI includes a PTRS-DMRS association field, The PTRS port associated with the above PTRS is associated with codebook based UL transmission based on one or more antenna ports, Based on the number of the above one or more antenna ports being 3 and 2 PTRS ports being configured: The number of bits in the above PTRS-DMRS association field is 1, Based on the PTRS-DMRS association field, one of the two DMRS ports sharing the first PTRS port is indicated, and the two DMRS ports are associated with two of the three antenna ports, A method characterized in that the second PTRS port is associated with the remaining antenna ports among the three antenna ports. In the first paragraph, Based on the number of the above one or more antenna ports being 4 and the above two PTRS ports being set: The number of bits in the above PTRS-DMRS association field is 2, One of the two first DMRS ports sharing the first PTRS port is indicated based on the value of the MSB (Most Significant Bit) of the PTRS-DMRS association field, One of the two second DMRS ports sharing the second PTRS port is indicated based on the value of the LSB (Least Significant Bit) of the PTRS-DMRS association field, A method characterized in that the two first DMRS ports are associated with two antenna ports among the four antenna ports, and the two second DMRS ports are associated with the remaining two antenna ports among the four antenna ports. In the first paragraph, Based on the number of said one or more antenna ports being 8 and said two PTRS ports being set: The number of bits in the above PTRS-DMRS association field is 4, One of the four first DMRS ports sharing the first PTRS port is indicated based on the values of the two MSBs (Most Significant Bits) of the PTRS-DMRS association field, One of the four second DMRS ports sharing the second PTRS port is indicated based on the values of the two LSBs (Least Significant Bits) of the PTRS-DMRS association field. A method characterized in that the four first DMRS ports are associated with four antenna ports among the eight antenna ports, and the four second DMRS ports are associated with the remaining four antenna ports among the eight antenna ports. In the first paragraph, The above DCI includes precoding information and number of layers field, A method characterized in that a Transmitted Precoding Matrix Indicator (TPMI) is indicated based on the above precoding information and layer number fields. In the fourth paragraph, The precoding matrix based on the above TPMI includes at least one column consisting of three rows, A method characterized in that the above three rows are associated with the above three antenna ports. In clause 5, A method characterized in that the above precoding matrix is related to i) partial-coherent codebook based UL transmission or ii) non-coherent codebook based UL transmission. In Article 6, The above two antenna ports are associated with two of the three elements in the at least one column, A method characterized in that each of the above two components is based on a value other than zero. In the first paragraph, The above two antenna ports are antenna ports 1000 and 1002, A method characterized in that the remaining antenna port is antenna port 1001. In the first paragraph, Based on the number of the above one or more antenna ports being 3 and 1 PTRS port being configured: The number of bits in the above PTRS-DMRS association field is 1, A method characterized in that one of two DMRS ports sharing one PTRS port is indicated based on the PTRS-DMRS association field. In Article 9, A method characterized in that the above two DMRS ports are associated with specific two antenna ports among the above three antenna ports. In Article 10, A method characterized in that the above specific two antenna ports are related to partial-coherent codebook based UL transmission. In Article 10, A method characterized in that the above two specific antenna ports include i) one port determined from among two ports related to partial-coherent codebook based UL transmission and ii) one port remaining from among the three ports excluding the two ports. In Article 10, A method characterized in that the above two specific antenna ports are determined based on the order of the antenna port index among the above three ports. At the terminal, One or more transmitters and receivers; one or more processors; and comprising one or more memories connected to said one or more processors and storing instructions; A terminal characterized in that the instructions, based on being executed by the one or more processors, cause the terminal to perform all steps of the method according to any one of claims 1 to 13. In a device comprising one or more memories and one or more processors functionally connected to the one or more memories, A device characterized in that said one or more memories store instructions that cause said device to perform all steps of a method according to any one of claims 1 to 13, based on being executed by said one or more processors. In a non-transitory computer-readable storage medium storing instructions, A non-transitory computer-readable storage medium characterized in that the instructions, when executed by one or more processors, cause a terminal to perform all steps of a method according to any one of claims 1 to 13. In terms of method, A step of transmitting downlink control information (DCI) to a terminal; and A step of receiving a phase tracking reference signal (PTRS) from the terminal; Including, The above DCI includes a PTRS-DMRS association field, The PTRS port associated with the above PTRS is associated with codebook based UL transmission based on one or more antenna ports, Based on the number of the above one or more antenna ports being 3 and 2 PTRS ports being configured: The number of bits in the above PTRS-DMRS association field is 1, Based on the PTRS-DMRS association field, one of the two DMRS ports sharing the first PTRS port is indicated, and the two DMRS ports are associated with two of the three antenna ports, A method characterized in that the second PTRS port is associated with the remaining antenna ports among the three antenna ports. At the base station, One or more transmitters and receivers; one or more processors; and comprising one or more memories connected to said one or more processors and storing instructions; A base station, characterized in that said instructions, based on being executed by said one or more processors, cause said base station to perform all steps of the method according to claim 17.

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