Enhanced PTRS to DMRS port mapping for multi-codeword and multi-panel transmission

Abstract

The present disclosure describes several methods regarding how to perform an overhead efficient indication of phase tracking reference signal (PTRS) to demodulation reference signal (DMRS) mapping for a user equipment (UE) (20, 100) having up to 8 layers, up to 4 PTRS ports, up to 4 UE panels for simultaneous transmission, and up to 4 uplink (UL) codewords, each UE panel (110) having up to 8 layers, this may reduce downlink control information (DCI) overhead for UL communications.

Description

Technical Field

[0001] The present disclosure relates generally to a Phase Tracking Reference Signal (PTRS) for use in wireless communication systems, and more particularly to mapping of PTRS ports to uplink layers for uplink transmissions in a Multiple-Input Multiple-Output (MIMO) system. Background Art

[0002] In the current 3rd Generation Partnership Project (3GPP) specifications, Demodulation Reference Signal (DMRS) is used for coherent demodulation of physical layer data channels such as Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH). DMRS is confined to the resource blocks carrying the associated physical layer channels and mapped onto the allocated resource elements of the time-frequency resource grid so that the receiver can efficiently handle time / frequency selective fading radio channels.

[0003] In the new radio (NR), a phase tracking reference signal (PTRS) can also be configured for PUSCH transmission so that the receiver can correct phase noise related errors. In NR Release 15 (Rel-15), for waveforms based on cyclic prefix orthogonal frequency division multiplexing (CPOFDM), one or two PTRS ports for PUSCH are supported. Each PTRS port is associated with one of the DMRS ports for PUSCH.

[0004] In the current standard, PTRS to DMRS mapping (i.e., the indication used in the downlink control information (DCI) to specify which DMRS port a PTRS port should be associated with) is only designed for up to 2 PTRS ports, up to 4 uplink (UL) layers, and up to 1 UL codeword. In NR Rel-18, the number of UL layers will increase to 8, the number of simultaneously transmitting UE panels will increase to 2, and the number of UL codewords will most likely increase to 2. The extensions to the number of simultaneously transmitting UE panels, the maximum number of UL layers, and the maximum number of codewords are likely to be further extended in subsequent releases of NR and 6G, as multiple transmission-reception points (TRPs) (with more than 2 TRPs) and distributed multiple-input multiple-output (D MIMO) applications are expected to be introduced in 5G Advanced and / or 6G. In addition, UL is becoming a limiting factor in wireless communications, which has led to operators pushing for the introduction of further UL specification enhancements in 3GPP. In addition, more advanced UEs will be available in the market in the future, like fixed wireless access (DWA), connected vehicles, robots, machines, etc., in which more advanced transmit antenna architectures will be used (e.g., more than 2 UE panels at millimeter wave (mmWave) frequencies, and / or more than 2 ports per UE panel).

[0005] How to perform overhead efficient PTRS to DMRS mapping for cases with an extended number of UL layers, UL codewords, simultaneously transmitting UE panels, etc. is an open problem that needs to be solved. Summary of the invention

[0006] An object of the present invention may be to provide measures by which an overhead efficient PTRS to DMRS mapping can be achieved for the case of a UE panel with an extended number of UL layers, an extended number of UL codewords and / or an extended number of simultaneously transmitting.

[0007] The present disclosure describes several methods on how to perform overhead efficient indication of phase tracking reference signal (PTRS) to demodulation reference signal (DMRS) mapping for a user equipment (UE) having up to 8 layers, up to 4 PTRS ports, up to 4 simultaneously transmitting UE panels, and up to 4 uplink (UL) codewords, with each UE panel having up to 8 layers, which can reduce downlink control information (DCI) overhead for UL communications.

[0008] An exemplary embodiment of the present disclosure includes a method for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on an uplink. The method includes receiving a message containing a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one of one or more codewords for uplink transmission of a reference signal. The method further includes allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table, and transmitting the PTRS through the allocated PTRS ports.

[0009] Another exemplary embodiment of the present disclosure includes a method for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on an uplink. The method includes receiving a message including a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one antenna panel of a plurality of antenna panels for uplink transmission of a reference signal. The method further includes: allocating one or more PTRS ports to a corresponding uplink layer based on the specified entry in the mapping table, and transmitting the PTRS through the allocated PTRS port.

[0010] Another exemplary embodiment of the present invention includes a method for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on the uplink. The method includes indicating to a network node the ability to map PTRS to an uplink layer based on reciprocity. The method further includes: determining the strongest uplink layer based on reception of a downlink signal from the network node. The method further includes: adapting the mapping between sounding reference signal (SRS) ports or SRS resources so that the lowest SRS port index or the lowest SRS resource index is associated with the strongest uplink layer. The method further includes: allocating PTRS to the strongest uplink layer without explicit signaling from the network node to indicate the uplink layer used for PTRS.

[0011] Another exemplary embodiment of the present disclosure includes a method for receiving PTRS implemented by a network node in a wireless communication system using multi-layer transmission on an uplink. The method includes: sending a message containing a mapping parameter to a UE, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one of one or more codewords for uplink transmission of a reference signal, and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The method further includes: receiving PTRS through the allocated PTRS port.

[0012] Another exemplary embodiment of the present disclosure includes a method for receiving PTRS implemented by a network node in a wireless communication system using multi-layer transmission on an uplink. The method includes: sending a message including a mapping parameter to a UE, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry is associated with at least one of a plurality of antenna panels for uplink transmission of a reference signal, and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The method further includes: receiving PTRS via the allocated PTRS port.

[0013] Another exemplary embodiment of the present disclosure includes a method for receiving PTRS implemented by a network node in a wireless communication system using multi-layer transmission on an uplink. The method includes: receiving an indication of a UE capability to map PTRS to an uplink layer based on reciprocity from a UE. The method further includes: determining the strongest uplink layer. The method further includes: receiving PTRS from the UE on the strongest uplink layer without explicitly signaling the UE to indicate the uplink layer for PTRS.

[0014] Another exemplary embodiment of the present disclosure includes a wireless device in a wireless communication system using multi-layer transmission on an uplink, the wireless device being configured to transmit a PTRS. The wireless device is configured to receive a message containing a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one of one or more codewords for uplink transmission of a reference signal. The wireless device is further configured to allocate one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table, and transmit the PTRS through the allocated PTRS ports.

[0015] Another exemplary embodiment of the present disclosure includes a wireless device in a wireless communication system using multi-layer transmission on an uplink, the wireless device being configured to transmit a PTRS. The wireless device includes a communication circuit and a processing circuit for communicating with a network node. The processing circuit is configured to receive a message containing a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one of the one or more codewords for uplink transmission of a reference signal. The processing circuit is further configured to allocate one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table, and transmit the PTRS through the allocated PTRS ports.

[0016] Another exemplary embodiment of the present disclosure includes a wireless device in a wireless communication system using multi-layer transmission on an uplink, the wireless device being configured to transmit a PTRS. The wireless device is configured to receive a message containing a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one antenna panel of a plurality of antenna panels for uplink transmission of a reference signal. The wireless device is further configured to allocate one or more PTRS ports to a corresponding uplink layer based on the specified entry in the mapping table, and transmit the PTRS through the allocated PTRS ports.

[0017] Another exemplary embodiment of the present disclosure includes a wireless device in a wireless communication system using multi-layer transmission on an uplink, the wireless device being configured to transmit a PTRS. The wireless device includes a communication circuit and a processing circuit for communicating with a network node. The processing circuit is configured to receive a message containing a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one of a plurality of antenna panels for uplink transmission of a reference signal. The processing circuit is further configured to allocate one or more PTRS ports to a corresponding uplink layer based on the specified entry in the mapping table, and transmit the PTRS through the allocated PTRS port.

[0018] Another exemplary embodiment of the present disclosure includes a wireless device in a wireless communication system using multi-layer transmission on an uplink, the wireless device being configured to transmit PTRS. The wireless device is configured to indicate to a network node the ability to map PTRS to an uplink layer based on reciprocity. The wireless device is further configured to determine the strongest uplink layer based on reception of a downlink signal from a network node. The wireless device is further configured to adapt a mapping between SRS ports or SRS resources so that a lowest SRS port index or a lowest SRS resource index is associated with the strongest uplink layer. The wireless device is further configured to assign PTRS to the strongest uplink layer without explicit signaling from the network node to indicate the uplink layer used for PTRS.

[0019] Another exemplary embodiment of the present disclosure includes a wireless device in a wireless communication system using multi-layer transmission on an uplink, the wireless device being configured to transmit a PTRS. The wireless device includes a communication circuit for communicating with a network node. The processing circuit is configured to indicate to the network node the ability to map the PTRS to an uplink layer based on reciprocity. The processing circuit is further configured to determine the strongest uplink layer based on the reception of a downlink signal from the network node. The processing circuit is further configured to adapt the mapping between SRS ports or SRS resources so that the lowest SRS port index or the lowest SRS resource index is associated with the strongest uplink layer. The processing circuit is further configured to assign the PTRS to the strongest uplink layer without explicit signaling from the network node to indicate the uplink layer used for the PTRS.

[0020] Another exemplary embodiment of the present disclosure includes a network node in a wireless communication system using multi-layer transmission on an uplink, the network node being configured to receive PTRS from a UE. The network node is configured to send a message containing a mapping parameter to the UE, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry is associated with at least one of one or more codewords for uplink transmission of a reference signal, and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The network node is further configured to receive PTRS via the allocated PTRS port.

[0021] Another exemplary embodiment of the present disclosure includes a network node in a wireless communication system using multi-layer transmission on an uplink, the network node being configured to receive PTRS from a UE. The network node includes a communication circuit and a processing circuit for communicating with the UE. The processing circuit is configured to send a message containing a mapping parameter to the UE, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry is associated with at least one of one or more codewords for uplink transmission of a reference signal, and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The processing circuit is further configured to receive PTRS through the allocated PTRS port.

[0022] Another exemplary embodiment of the present disclosure includes a network node in a network node of a wireless communication system using multi-layer transmission on an uplink. The network node is configured to receive PTRS from a UE. The network node is further configured to send a message containing a mapping parameter to the UE, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry is associated with at least one of a plurality of antenna panels for uplink transmission of a reference signal, and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The network node is further configured to receive PTRS through the allocated PTRS port.

[0023] Another exemplary embodiment of the present disclosure includes a network node in a network node of a wireless communication system using multi-layer transmission on an uplink. The network node is configured to receive a PTRS from a UE. The network node includes a communication circuit for communicating with the UE. The network node further includes a processing circuit, which is configured to send a message containing a mapping parameter to the UE, and the mapping parameter has a value indicating one of a plurality of entries in a mapping table. Each entry is associated with at least one of a plurality of antenna panels for uplink transmission of a reference signal, and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The processing circuit is further configured to receive the PTRS through the allocated PTRS port.

[0024] Another exemplary embodiment of the present disclosure includes a network node in a wireless device in a wireless communication system using multi-layer transmission on an uplink. The network node is configured to transmit a PTRS from a UE. The wireless device is configured to receive an indication of a UE capability to map a PTRS to an uplink layer based on reciprocity from the UE. The wireless device is further configured to determine the strongest uplink layer. The wireless device is further configured to receive a PTRS from the UE on the strongest uplink layer without explicit signaling to the UE to indicate the uplink layer for the PTRS.

[0025] Another exemplary embodiment of the present disclosure includes a network node in a wireless device in a wireless communication system using multi-layer transmission on an uplink, the uplink being configured to transmit PTRS. The wireless device includes a communication circuit for communicating with the network node. The wireless device further includes a processing circuit configured to receive an indication of a UE capability of mapping PTRS to an uplink layer based on reciprocity from the UE. The processing circuit is further configured to determine the strongest uplink layer. The processing circuit is further configured to receive PTRS from the UE on the strongest uplink layer without explicit signaling to the UE to indicate the uplink layer for PTRS. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 An exemplary wireless communication network is shown.

[0027] Figure 2 The NR time domain structure with 15kHz subcarrier spacing is shown.

[0028] Figure 3 The NR physical resource grid is shown.

[0029] Figure 4 Demodulation reference signals (DMRS) for configuring type 1 and type 2 front loading are shown, where different code division multiplexing (CDM) groups are indicated by different shading.

[0030] Figure 5 An exemplary DMRS configuration for physical downlink shared channel (PDSCH) mapping type A is shown.

[0031] Figure 6 An exemplary DMRS configuration for PDSCH mapping type B is shown.

[0032] Figure 7 Exemplary PTRS resource elements (REs) in a resource block (RB) with a time density of 2 and a subcarrier offset of 4 are shown.

[0033] Figure 8 PTRS-DMRS association tables for one PTRS port, 1 UL codeword, with a maximum of 8 UL layers (left) and with a maximum of 4 UL layers (right) are shown according to some embodiments of the present disclosure.

[0034] Fig. 9 A PTRS-DMRS association table for one PTRS port, 1 UL codeword and having a maximum of 6 UL layers according to some embodiments of the present disclosure is shown, and wherein the number of entries in the table is rounded down to 4.

[0035] Fig.10A PTRS-DMRS association table for one PTRS port, 2 UL codewords and having a maximum of 8 UL layers according to some embodiments of the present disclosure is shown.

[0036] Fig.11 A PTRS-DMRS association table for one PTRS port, 4 UL codewords and having a maximum of 8 UL layers according to some embodiments of the present disclosure is shown.

[0037] Fig.12 SRS port to antenna port mapping according to some embodiments of the present disclosure is shown.

[0038] Fig.13 A PTRS-DMRS association table for 2 PTRS ports, 1 UL codeword, up to 8 UL layers and with 4 UE panels / antenna modules according to some embodiments of the present disclosure is shown.

[0039] Fig.14 A PTRS-DMRS association table for 2 PTRS ports, 2 codewords and up to 8 UL layers is shown, wherein the entries are divided into two parts for the first codeword and the second codeword, according to some embodiments of the present disclosure.

[0040] Fig.15 A PTRS-DMRS association table for 2 PTRS ports, 4 codewords and up to 8 UL layers is shown, wherein the entries are divided into two parts for the first codeword and the second codeword, according to some embodiments of the present disclosure.

[0041] Fig.16 A PTRS-DMRS association table for 2 configured UL PTRS ports and 4 configured UL codewords and up to 8 UL layers is shown according to some embodiments of the present disclosure.

[0042] Fig.17 A PTRS-DMRS association table for 2 PTRS ports, 1 or 2 UL codewords, and up to 4 UL layers according to some embodiments of the present disclosure is shown.

[0043] Fig.18 A PTRS-DMRS association table for 4 PTRS ports, 4 codewords, and up to 8 UL layers is shown according to some embodiments of the present disclosure.

[0044] Fig.19 A PTRS-DMRS association table for 4 PTRS ports and 4 SRS resource sets according to some embodiments of the present disclosure is shown.

[0045] Fig. 20An exemplary method implemented by a wireless device in a wireless communication system using multi-layer transmission on an uplink for transmitting a PTRS is shown.

[0046] Fig.21 A method for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on an uplink is shown.

[0047] Fig. 22 A method for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on an uplink is shown.

[0048] Fig.23 A method implemented by a network node in a wireless communication system using multi-layer transmission on uplink for receiving PTRS is shown.

[0049] Fig.24 A method implemented by a network node in a wireless communication system using multi-layer transmission on uplink for receiving PTRS is shown.

[0050] Fig.25 A method implemented by a network node in a wireless communication system using multi-layer transmission on uplink for receiving PTRS is shown.

[0051] Fig.26 A UE configured to transmit PTRS is shown.

[0052] Fig. 27 A base station / network node configured for receiving PTRS is shown. DETAILED DESCRIPTION

[0053] The present disclosure will be described in the context of a fifth generation (5G) network implementing a new radio (NR) air interface. Those skilled in the art will appreciate that the techniques described herein are more generally applicable to any wireless communication network implementing PTRS on the uplink.

[0054] Figure 1A multiple-input multiple-output (MIMO) wireless communication system 10 is shown, which includes a transmitting station 20 and a receiving station 30 communicating over a MIMO channel 15. For downlink communications, the transmitting station 20 includes a network node or base station, also referred to as a 5G NodeB (gNB) in NR, and the receiving station 30 includes a user equipment (UE). Examples of UEs include cellular phones, smart phones, tablets, notebooks, laptops, laptop-mounted equipment (LME), vehicle-to-vehicle (V2V) communication devices, vehicle-to-everything (V2X) communication devices, machine-type communication (MTC) devices, machine-to-machine M2M communication devices, etc. For uplink communications, the transmitting station 20 includes a UE, and the receiving station 30 includes a base station (e.g., a gNB). Both the transmitting station 20 and the receiving station 30 have multiple antennas 25, 35. The use of multiple antennas 25, 35 at both the transmitting station 20 and the receiving station 30 enables spatial multiplexing, which is a multi-antenna transmission technique in which multiple data streams are transmitted in different spatial layers using the same time / frequency resources. Spatial multiplexing enables higher data rates and more efficient use of spectrum resources. To enable spatial multiplexing, DMRS are transmitted on each spatial layer to enable coherent demodulation at the receiver, as described below.

[0055] NR frame structure and resource grid

[0056] Figure 2 The NR time domain structure with 15kHz subcarrier spacing is shown. NR uses cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) in both the downlink (i.e., from the network node, gNB or base station to the UE) and the uplink (i.e., from the UE to the gNB). Discrete Fourier transform (DFT) spread orthogonal frequency division multiplexing (DFT-S-OFDM) is also supported in the uplink. In the time domain, the NR downlink and uplink are organized into equal-sized subframes of 1ms each. The subframes are further divided into multiple slots of equal duration. The slot length depends on the subcarrier spacing. For a subcarrier spacing of Δf=15kHz, there is only one slot per subframe, and each slot consists of 14 OFDM symbols.

[0057] Data scheduling in NR is usually performed on a time slot basis. Figure 2 The example shown in is for an NR time domain structure with 15kHz subcarrier spacing and 14 symbol slots, the first two symbols containing the Physical Downlink Control Channel (PDCCH), and the remaining slots containing physical layer data channels, which may include a Physical Downlink Shared Channel (PDSCH) or a Physical Uplink Shared Channel (PUSCH).

[0058] Different subcarrier spacing values ​​are supported in NR. The supported subcarrier spacing values ​​(also called different parameter sets) are given by Δf=(15×2 μ )kHz, where μ∈0,1,2,3,4. Δf=15kHz is the basic subcarrier spacing. The time slot duration when different subcarrier spacing is taken is given by Given.

[0059] In the frequency domain, the system bandwidth is divided into resource blocks (RBs), each resource block corresponds to 12 consecutive subcarriers, and the RBs are numbered starting from 0 at one end of the system bandwidth. Figure 3 The basic NR physical time-frequency resource grid is shown in FIG, where only one RB within a slot of 14 symbols is shown. One OFDM subcarrier during one OFDM symbol interval forms one resource element (RE).

[0060] Downlink (DL) PDSCH transmission can be dynamically scheduled, i.e., in each slot, the gNB transmits downlink control information (DCI) via PDCCH (Physical Downlink Control Channel) about which UE the data will be transmitted to and on which RBs in the current downlink slot; or semi-persistently scheduled (SPS), where periodic PDSCH transmission is activated or deactivated via DCI. In NR, different DCI formats are defined for DL ​​PDSCH scheduling, including DCI format 1_0, DCI format 1_1, and DCI format 1_2.

[0061] Similarly, uplink grants carried in PDCCH can also be used to dynamically or semi-persistently schedule uplink (UL) PUSCH transmissions. NR supports two types of semi-persistent uplink transmissions, namely, type 1 configuration grants (CGs) and type 2 CGs, where type 1 CGs are configured and activated through radio resource control (RRC), and type 2 CGs are configured through radio resource control (RRC), but activated / deactivated through DCI. The DCI formats used to schedule PUSCH include DCI format 0_0, DCI format 0_1, and DCI format 0_2.

[0062] DMRS Configuration

[0063] Demodulation Reference Signal (DMRS) is used for coherent demodulation of physical layer data channels (i.e., PDSCH and PUSCH) and PDCCH. DMRS is confined to the resource blocks carrying the associated physical layer channels and mapped onto the allocated REs of the time-frequency resource grid so that the receiver can efficiently handle time / frequency selective fading radio channels.

[0064] The mapping of DMRS to RE is configurable in both frequency and time domains. There are two mapping types in the frequency domain, namely, type 1 and type 2. In addition, there are two mapping types in the time domain, namely, mapping type A and type B, which define the symbol position of the first OFDM symbol containing DMRS in the transmission interval.

[0065] DMRS mapping in the time domain can also be single-symbol based or dual-symbol based, where the latter means that the DMRS is mapped to a pair of two adjacent OFDM symbols. For single-symbol based DMRS, one, two, three or four single-symbol DMRS (also called additional DMRS) can be configured for the UE in a time slot. For dual-symbol based DMRS, one or two such dual-symbol DMRS can be configured for the UE in a time slot. In scenarios with low Doppler, it may be sufficient to configure only the front-end loaded DMRS (i.e., one single-symbol DMRS or one dual-symbol DMRS). In scenarios with high Doppler, additional DMRS will be required in the time slot.

[0066] Figure 4 An example of a time domain mapping type A in which the first DMRS is in the third OFDM symbol of a transmission interval of 14 symbols is shown using type 1 and type 2 front-loading DMRS of single-symbol and double-symbol DMRS. Figure 4 As shown in , type 1 and type 2 are different in terms of mapping structure and the number of supported DMRS code division multiplexing (CDM) groups, where type 1 supports 2 CDM groups and type 2 supports 3 CDM groups.

[0067] DMRS antenna ports are mapped to REs within only one CDM group. For single-symbol DMRS, two antenna ports may be mapped to each CDM group, while for dual-symbol DMRS, four antenna ports may be mapped to each CDM group. Therefore, for DMRS type 1, the maximum number of DMRS ports is 4 for single-symbol based DMRS configuration and 8 for dual-symbol based DMRS configuration. For DMRS type 2, the maximum number of DMRS ports is 6 for single-symbol based DMRS configuration and 12 for dual-symbol based DMRS configuration.

[0068] An orthogonal cover code (OCC) of length 2 (ie, [+1, +1] or [+1, -1]) is used to separate antenna ports mapped in the same two REs within a CDM group. When dual-symbol DMRS is configured, OCC is applied in the frequency domain (FD) and in the time domain (TD). Figure 4 The OCC for CDM group 0 is shown in FIG.

[0069] In NR Rel-15, in 3GPP TS 38.211, e.g., V17.2.0 (2022-06), the mapping of the PDSCH DMRS sequence r(m), m=0, 1, ..., on antenna port p and subcarrier k for parameter set index μ in OFDM symbol l is specified as: k′=0,1 n=0,1,... Among them, w f (k′) represents a 2OCC code, and w t (l′) represents an OCC code with a time domain length of 2.

[0070] Table 1 and Table 2 show PDSCH DMRS mapping parameters for configuring Type 1 and Type 2, respectively.

[0071] Table 1. PDSCH DMRS mapping parameters for configuration type 1.

[0072] Table 2. PDSCH DMRS mapping parameters for configuration type 2.

[0073] For PDSCH mapping type A, DMRS mapping is relative to the slot boundary. That is, the first front-loaded DMRS symbol in DMRS mapping type A is in the 3rd or 4th symbol of the slot. In addition to the front-loaded DMRS, type A DMRS mapping can also contain up to 3 additional DMRS. Figure 5 Some examples for mapping type A DMRS are shown in FIG. 5 (note that a PDSCH length of 14 symbols is assumed in this example).

[0074] Figure 5 It is assumed that the PDSCH duration is a full slot. If the scheduled PDSCH duration is shorter than a full slot, the position of the DMRS changes according to specification TS 38.211, e.g., V17.2.0 (2022-06).

[0075] For PDSCH mapping type B, DMRS mapping is relative to the start of transmission. That is, the first DMRS symbol in DMRS mapping type B is in the first symbol of the start of type B PDSCH. Figure 6 Some examples for mapping type B DMRS are shown in FIG.

[0076] When transform precoding is not enabled, the same DMRS design for PDSCH also applies to PUSCH, where the sequence r(m) should be mapped to the DMRS ports according to the following formula The intermediate amount k′=0,1 n=0,1,… j=0,1,…,v-1 Among them, w f (k′), w t (l′) and Δ are given by Tables 6.4.1.1.3-1 and 6.4.1.1.3-2 in TS 38.211, e.g., V17.2.0 (2022-06) (these tables are reproduced below), and v is the number of PUSCH transmission layers. If Δ corresponds to For any other antenna port other than

[0077] Intermediate should be precoded as follows, multiplied by the amplitude scaling factor In order to comply with the transmit power specified in clause 6.2.2 of TS38.214, e.g. V17.2.0 (2022-06), and mapped to physical resources: Wherein, the precoding matrix W is given by clause 6.3.1.5 of TS 38.211, e.g., V17.2.0 (2022-06), {p0, ..., p p-1} is the set of physical antenna ports used to transmit PUSCH, and It is the set of DMRS ports used for PUSCH.

[0078] Table 6.4.1.1.3-1: Parameters for PUSCH DMRS configuration type 1.

[0079] Table 6.4.1.1.3-2: Parameters for PUSCH DMRS configuration type 2.

[0080] PTRS for PUSCH in NR

[0081] In NR, PTRS can be configured for PUSCH transmissions so that the receiver can correct for phase noise related errors. For PUSCH scheduled by DCI format 0_1 ​​or DCI format 0_2, PTRS can be configured using PTRS-UplinkConfig in the higher layer parameter DMRS-UplinkConfig.

[0082] In NR Rel.15, for CP OFDM-based waveforms, one or two PTRS ports for PUSCH are supported. Each PTRS port is associated with one of the DMRS ports for PUSCH.

[0083] If more than one DMRS port is scheduled, i.e., multi-layer MIMO transmission of PUSCH, from a performance point of view, it is desirable to transmit PTRS in the layer with the highest signal to interference plus noise ratio (SINR). This approach will maximize the phase tracking performance. The network knows which layer has the best SINR based on the measurement of the multi-port sounding reference signal (SRS). Therefore, the network can indicate which layer the UE should use to transmit PTRS when scheduling PUSCH from the UE. This indication is signaled using the PTRS-DMRS association as defined below.

[0084] Based on the need reported by the UE, the maximum number of configured PTRS ports is given by the higher layer parameter maxNrofPorts in PTRS-UplinkConfig. If the UE has reported the capability to support fully coherent UL transmissions, then one PTRS port is expected to be configured if needed.

[0085] In the frequency domain, for CP OFDM-based waveforms, PTRS can be in at most one subcarrier for every 2 physical resource blocks (PRBs). Moreover, the subcarrier used for the PTRS port must be one of the subcarriers that is also used for the DMRS port associated with that PTRS port. For DMRS configuration type 1, the DMRS port is mapped to every second subcarrier. Therefore, the associated PTRS can only be mapped to one of the 6 subcarriers. An offset can be configured to determine which subcarrier the DMRS is mapped to (see Table 6.4.1.2.2.1-1 in 3GPP TS 38.211, e.g., V17.2.0 (2022-06)).

[0086] In the time domain, PTRS can be configured with a time density of 1, 2, or 4, corresponding to PTRS in every OFDM symbol, every second OFDM symbol, or every fourth OFDM symbol in a slot, respectively. The modulation symbols used for PTRS are the same as the associated DMRS on the same subcarrier.

[0087] Figure 7An example of a PTRS RE with a time density of 2 in an RB and a subcarrier offset of 4 is shown for a CP OFDM based waveform. In this example, the PTRS port is associated with DMRS port 0 and has a subcarrier offset of 4 and a time density of 2.

[0088] For codebook or non-codebook based UL transmission, the association between UL PTRS port(s) and DMRS port(s) is signaled by the PTRSDMRS Association field in DCI format 0_1 ​​and DCI format 0_2.

[0089] If the UE is configured with one PTRS port, the DMRS port associated with the PTRS port is indicated by the DCI parameter PTRSDMRS association in DCI format 0_1 ​​and DCI format 0_2 in Table 7.3.1.1.2-25 of 3GPP TS 38.212, e.g., V17.2.0 (2022-06), which is reproduced below. As discussed above, the goal is to schedule PTRS to be transmitted on the strongest layer / DMRS port (since there is one DMRS port per layer).

[0090] Table 7.3.1.1.2-25: PTRS-DMRS association for UL PTRS port 0 value DMRS Port 0 First scheduled DMRS port 1 Second scheduled DMRS port 2 The third scheduled DMRS port 3 Fourth scheduled DMRS port

[0091] For non-codebook based UL transmission, the actual number of (one or more) PTRS ports to be transmitted is determined based on the (one or more) sounding reference signal (SRS) resource indicator SRI in DCI format 0_1 ​​and DCI format 0_2. The PTRS port index for each configured SRS resource is configured for the UE through the higher layer parameter ptrs-PortIndex configured by SRS-Config. If the PTRS port index associated with different SRIs is the same, the corresponding UL DMRS port is associated with one PTRS port.

[0092] For UL transmissions based on partially coherent and non-coherent codebooks, the actual number of UL PTRS ports (one or more) is determined based on the transmit precoding matrix indicator (TPMI) and / or the number of layers specified by the precoding information and number of layers field in DCI format 0_1 ​​and DCI format 0_2. If the UE is configured with 2 PTRS ports, the actual PTRS port (one or more) and the associated transmission layer (one or more) are derived from the specified TPMI as follows:

[0093] • PUSCH antenna ports 1000 and 1002 in the specified TPMI share PTRS port 0, and PUSCH antenna ports 1001 and 1003 in the specified TPMI share PTRS port 1.

[0094] PTRS port 0 is associated with a DMRS port that is transmitted with PUSCH antenna port 1000 and PUSCH antenna port 1002 in the specified TPMI, and PTRS port 1 is associated with another DMRS port that is transmitted with PUSCH antenna port 1001 and PUSCH antenna port 1003 in the specified TPMI, where these two DMRS ports are given by the DCI parameter 'PTRSDMRS association' in DCI format 0_1 ​​and DCI format 0_2 in Table 7.3.1.1.2-26 of 3GPP TS 38.212, e.g., V17.2.0 (2022-06), which is copied below.

[0095] Table 7.3.1.1.2-26: PTRS-DMRS association for UL PTRS ports 0 and 1

[0096] NR Rel-17 and Rel-18 enhancements for PUSCH transmission to two TRPs

[0097] In NR Rel-17, support for PUSCH repetition to two transmission-reception points (TRPs) was introduced. For this purpose, two SRS resource sets whose usage is set to be codebook-based or non-codebook-based are introduced, where each SRS resource set is associated with a TRP. PUSCH repetition to two TRPs can be scheduled by a DCI with two SRS resource indicators (SRIs), where the first SRI is associated with the first SRS resource set and the second SRI is associated with the second SRS resource set.

[0098] In NR Rel-18, simultaneous multi-panel UL transmissions will be specified, where a UE will transmit PUSCH from two different UE panels to two different TRPs simultaneously. It is expected that the transmission from each UE panel is associated with one SRS resource set (i.e., one SRS resource set per UE panel / TRP as in Rel-17 PUSCH repetition) or with one SRS resource (i.e., one SRS resource per UE panel / TRP).

[0099] The present disclosure describes several methods on how to perform overhead efficient indication of PTRS to DMRS mapping for UEs with up to 8 layers, up to 4 PTRS ports, up to 4 UE panels transmitting simultaneously, up to 4 UL codewords and up to 8 layers per UE panel, which can reduce the DCI overhead for UL communications.

[0100] In one embodiment, for a single configured UL PTRS port and a single configured UL codeword, the number of entries of the associated PTRSDMRS association table is equal to the maximum number of configured UL layers.

[0101] Figure 8 Two examples of PTRSDMRS mapping are shown. Figure 8 The table on the left in FIG. 1 is for a UE configured with one PTRS port, one codeword and a maximum of 8 UL layers, which results in 8 entries of the PTRSDMRS association table. Figure 8 The table on the right in the middle is for a UE configured with one PTRS port, one codeword and a maximum of 4 UL layers, which results in 4 entries of the PTRSDMRS association table. In one embodiment, a different table is provided for each possible configuration of the maximum number of UL layers.

[0102] Currently in NR, PTRS is mainly targeted at millimeter wave (mmWave) frequencies. Moreover, since one PTRS per UE panel (i.e., per local oscillator (LO)) is usually sufficient, and since UE panels are usually equipped with 2 transmit (TX) chains, support for a single PTRS and up to 8 layers in NR may be considered unnecessary. However, new frequency bands (6GHz–24GHz) between frequency range 1 (FR1) and frequency range 2 (FR2) will be specified in NR, where there may be antenna architectures using up to 8 ports for one UE panel, while still requiring PTRS. Furthermore, in 6G, digital beamforming may become available also at very high frequencies. Therefore, in 6G, it is possible that up to 8 layers may be required for a single PTRS port.

[0103] Because the number of code points required for the PTRS to UL layer mapping bit field (for example, the "PTRS-DMRS association" bit field in DCI formats 0_1, 0_2 in NR) depends on the number of entries in the PTRSDMRS association table, the number of bits required for PTRS to UL layer mapping can be reduced when a smaller maximum number of UL layers is configured for the UE, which will reduce the DCI overhead when the UE is configured with less than the maximum number of UL layers it supports.

[0104] In one embodiment, the number of entries in the PTRSDMRS association table is configurable. For example, even if the UE is configured with a maximum value of 8 UL layers, it is possible to have an RRC configuration in which the maximum number of layers to which the PTRS can be associated (i.e., the number of entries in the PTRSDMRS association table) is configured to be a smaller number. In one example, even if the UE is configured with a maximum value of 8 UL layers, the UE is only configured with 4 entries in the PTRSDMRS association table, which means that only the PTRS to DMRS mapping associated with one of the 4 first DMRS ports can be indicated to the UE (this will reduce the DCI overhead from 3 bits to 2 bits). For example, if the UE can determine the strongest UL layer based on DL reception and reciprocity, this may be useful. In this case, the UE can adapt the SRS transmission in the following manner: the SRS port with the lowest SRS port index (in the case of UL transmission based on non-coherent codebook) or the SRS resource with the lowest SRS resource index (in the case of UL transmission based on non-codebook) is associated with the strongest UL layer.

[0105] In one embodiment, for a single configured UL PTRS port and a single configured UL codeword, the number of entries in the PTRSDMRS association table is automatically equal to the maximum number of configured UL layers, but rounded down to a number that is a factor of 2 (ie, 2, 4, 8, etc.). Fig. 9 A PTRSDMRS association table is shown, where the UE is configured with one PTRS port, one UL codeword, a maximum of 6 UL layers, and only 4 of the first layers can be associated with PTRS. This mapping reduces the number of bits required to specify the PTRS to DMRS mapping (e.g., the PTRSDMRS association bit field in DCI format 0_1 ​​in NR) in an overhead efficient manner. For example, if the UE is configured with a maximum of 6 UL layers, the UE would instead require 6 code points (3 bits) in the PTRS to UL layer mapping bit field. However, in this example, the number of code points is rounded down to 4, which means that 2 bits are required instead of 3 bits.

[0106] In some embodiments, for a single configured UL PTRS port, the number of entries in the PTRSDMRS association table is equal to the maximum number of configured UL layers divided by the maximum number of configured UL codewords. The entries of the PTRSDMRS association table are associated with the UL layers, which are associated with the UL codewords with the highest MCS (because the strongest UL layer is likely to be associated with the strongest UL codeword).

[0107] Fig.10An example of a PTRSDMRS association table is shown, where the UE is configured with one PTRS port, up to 8 UL layers, and two UL codewords, and where the number of entries is equal to the maximum number of UL layers (8) divided by the number of UL codewords (2), e.g., 8 / 2=4. In this example, the entries in the table are associated with UL layers, which are associated with UL codewords with the highest modulation and coding scheme (MCS). This mapping will reduce the number of bits required in the PTRS to DMRS mapping (e.g., the PTRSDMRS association bit field in DCI format 0_1 ​​in NR) from 3 bits to 2 bits. In the case where two UL codewords have the same MCS, one of them can be selected based on another criterion. For example, in the case where two UL codewords share the same (e.g., highest) MCS, one can be selected based on the lowest codeword identifier (ID).

[0108] Fig.11 A PTRSDMRS association table for one PTRS port, four UL codewords, and up to 8 UL layers is shown, wherein the number of entries in the table is equal to the maximum number of UL layers divided by the number of UL codewords. In this example, according to some embodiments of the present disclosure, the entries in the table are associated with UL layers, and the UL layers are associated with the UL codewords with the highest MCS.

[0109] In one embodiment, the UE has reported a reciprocity-based PTRS to UL layer mapping capability. In this case, it is assumed that the UE can determine the strongest UL layer(s) based on DL reception. Based on the determined strongest layers, the UE adapts the SRS port / resource to UE antenna mapping in such a way as to associate PTRS with the strongest UL layer(s). By adapting the mapping at the UE, the network does not need to indicate to the UE which UL layer the UE should associate PTRS with, and therefore the PTRS to UL layer mapping bit field can be cancelled (which saves DCI overhead).

[0110] Fig.12An exemplary embodiment according to the present disclosure is shown, in which the UE adapts the SRS port to antenna port mapping to ensure that the UE antenna with the strongest link to the serving TRP is associated with the SRS port with the lowest SRS port index so that the PTRS is always mapped to the strongest layer. This example is for a non-coherent UE with two UE antennas, in which the UE is configured with a dual-port SRS resource with a usage 'codebook'. The UE is configured with a non-coherent codebook and can therefore be scheduled using one of the following candidate precoders: [1,0] (i.e., single layer PUSCH transmission on the first UE antenna), [0,1] (i.e., single layer PUSCH transmission on the second UE antenna), or [1,1] (i.e., two layers of PUSCH transmission, one layer for each antenna). It is further assumed that one PTRS port is configured for the UE. Given that the UE is scheduled for two-layer UL transmission (i.e., precoder [1,1]), a bit field in the DCI (PTRS to UL layer mapping bit field) would traditionally be used to indicate which is the strongest UL layer, and therefore to which UL layer (or DMRS port) the UE should associate the PTRS. However, in this example, the UE uses DL reception to determine which UE antenna is the strongest, and maps the SRS port with the lowest SRS port ID to that UE antenna. In this way, if it is assumed that the PTRS should be associated with the first specified DMRS port for PUSCH, and that first specified DMRS port is associated with the SRS port with the lowest SRS port ID, the UE will automatically assign the PTRS to the stronger UL layer, and the DCI indication (PTRS to UL layer mapping bit field) can be canceled. This is in Fig.12 , where the UE in the first case detects (based on, for example, DL reception) that UE antenna 1 has the strongest link to the serving TRP and therefore transmits SRS port 1 from UE antenna 1. Fig.12 ), the UE detects that UE antenna 2 has the strongest link to the serving TRP and then maps SRS port 1 to UE antenna 1. In both cases, if a single PTRS is configured for the UE and the UE is scheduled with rank 2, the PTRS will be automatically associated with the strongest layer (the first DMRS port), which means that no DCI indication for PTRS is required (PTRS to UL layer mapping bit field).

[0111] Fig.12 The SRS port to antenna port mapping for a single PTRS and the strongest UL layer is shown, however, the SRS port to antenna port mapping can be easily extended to the case where N PTRS are mapped to the N strongest layers. Similarly, Fig.12A non-coherent codebook is assumed, however, for partially coherent or fully coherent UL codebooks, the SRS port to antenna port mapping can be performed in a similar manner. For fully coherent UEs, the UE needs to determine the phase of each SRS for each antenna port as follows: The strongest precoder will correspond to the first column in the precoding matrix as specified in (TS 38.211 e.g. V17.2.0 (2022-06) Table 6.3.1.5-4 to Table 6.3.1.5-7).

[0112] In one embodiment, the same approach is used for non-codebook based UL transmissions, where the UE determines the SRS precoder based on DL reference signal measurements and reciprocity. By transmitting the SRS port / resource with the lowest SRS port / SRS resource index in the strongest direction towards the network, the PTRS will automatically be associated with the strongest layer and the PTRS to UL layer mapping bit field can be eliminated. This approach can be easily extended to X PTRS by precoding the X SRS ports / resources with the lowest SRS port ID / resource ID in the X strongest directions.

[0113] Example involving 2 PTRS ports

[0114] In one embodiment, for two configured UL PTRS ports, a single configured UL codeword, and in the case where the UE is equipped with 4 UE panels / UE antenna modules (for simultaneous UL transmission), the PTRSDMRS association table and the corresponding PTRS to UL layer mapping bit field are divided into multiple parts: the first part is used to indicate which / which of the multiple UE panels / UE antenna modules the PTRS should be associated with. The remaining parts indicate which UL layers the PTRS should be associated with that are associated with the (one or more) specified UE panels / UE antenna modules.

[0115] In some embodiments, the first part of the table / bit field may be associated with a UL-RS (SRS) resource set or a UL-RS (SRS) resource. Thus, the first part of the table / bit field may be used to indicate a UL-RS resource set or a UL-RS resource instead of a UE panel. It is also possible that an explicit UE panel ID or a virtual UE panel ID may be introduced in NR or 6G, in which case the first part of the table / bit field may be used to indicate a virtual UE panel ID or an explicit UE panel ID.

[0116] Fig.13An example PTRS-DMRS association table for one PTRS port, one UL codeword, up to 8 UL layers, and 4 UE panels / antenna modules is shown. The first part of the table is used to indicate which UE panels / UE antenna modules the PTRS should be associated with, and the remainder indicates which UL layer of the indicated UE panel / UE antenna module the PTRS should be associated with. In this case, the first three bits of the PTRS to UL layer mapping bit field are used to indicate which UE panels / UE antenna modules the fourth and fifth bits of the PTRS to UL layer mapping bit field are associated with. This will reduce the number of bits required compared to explicitly indicating which DMRS port the first PTRS port should be associated with (8 code points) and then indicating which DMRS port the second PTRS port should be associated with (6 code points) (which requires 6 bits, rather than the 5 bits required in this example).

[0117] In some embodiments, the UE panel is not explicitly defined in the specification. Instead, the UE panel indication may be associated with an SRS resource set or an SRS resource. In this case, for example, instead of Fig.13 The UE panel ID in the table in may be replaced by SRS resource ID and / or SRS resource set ID in the specification.

[0118] In one embodiment shown, for two configured UL PTRS ports and two configured UL codewords, the entries of the PTRSDMRS association table are divided into two parts, wherein the first part is used to indicate the PTRS to DMRS mapping for the first codeword, and the second part is used to indicate the PTRS to DMRS mapping for the second codeword. Fig.14 An example PTRS-DMRS association table for two UL PTRS ports and two UL codewords is shown, wherein entries of the PTRS-DMRS association table are divided into two parts, a first part indicating a PTRS to DMRS mapping for a first codeword, and a second part indicating a PTRS to DMRS mapping for a second codeword.

[0119] exist Fig.15 In one embodiment shown in , for two configured UL PTRS ports and four configured UL codewords, the entries of the PTRSDMRS association table are divided into two parts. The first part indicates the PTRS to DMRS mapping for the first codeword, and the second part indicates the PTRS to DMRS mapping for the second codeword. The first codeword is the codeword with the highest MCS, and the second codeword is the codeword with the second highest MCS. In case two UL codewords have the same MCS, one of them is selected based on another criterion, such as based on the lowest codeword ID.

[0120] exist Fig.16In one embodiment shown in , for two configured UL PTRS ports and four configured UL codewords, the PTRSDMRS association table is divided into multiple parts. The first part indicates which of the codewords the PTRS should be associated with. The remaining parts indicate which UL layers the PTRS should be associated with that are associated with the specified codewords. Fig.16 In the example, the first three bits of the PTRS to UL layer mapping bit field are used to indicate which codewords the fourth and fifth bits of the PTRS to UL layer mapping bit field are associated with. This reduces the number of bits required compared to explicitly indicating which DMRS port the first PTRS port should be associated with (8 code points) and then indicating which DMRS port the second PTRS port should be associated with (6 code points), which requires 6 bits instead of the 5 bits required in this example.

[0121] exist Fig.17 In one embodiment shown in , a UE is configured with two UL PTRS ports and two SRS resource sets for simultaneous transmission (STxMP) from multiple panels on a total of up to 4 layers, with a maximum of two layers per UE panel. The UE is configured with two SRS resource sets with usage 'codebook' and / or 'non-codebook', each SRS resource set having two SRS ports. In this case, the first bit of the PTRS to UL layer mapping bit field is used to indicate which of the two layers associated with the first SRS resource set the first PTRS should be mapped to, and the second bit of the PTRS to UL layer mapping bit field is used to indicate which of the two layers associated with the second SRS resource set the second PTRS should be mapped to. In one embodiment, the SRS resource sets are changed to SRS resources.

[0122] Embodiment involving 4 PTRS ports

[0123] Four PTRS ports may be introduced in 5G Advanced and / or 6G to handle UEs with 4 panels or 4 antenna modules (where the UE can transmit from all 4 panels / antenna modules simultaneously).

[0124] exist Fig.18 In one embodiment shown in , for four configured UL PTRS ports and four configured UL codewords, the entries of the PTRSDMRS association table are divided into four parts, wherein the first part is used to indicate the PTRS to DMRS mapping for the first codeword, the second part is used to indicate the PTRS to DMRS mapping for the second codeword, the third part is used to indicate the PTRS to DMRS mapping for the third codeword, and the fourth part is used to indicate the PTRS to DMRS mapping for the fourth codeword.

[0125] exist Fig.19In one embodiment shown in , the UE is configured with four UL PTRS ports and four SRS resource sets for STxMP operation on a total of up to 8 layers, with up to four UE panels and a maximum of two layers per UE panel. The UE is configured with four SRS resource sets (each with two SRS ports) with usage 'codebook' and / or 'non-codebook'. In this case, the first bit of the PTRS to UL layer mapping bit field is used to indicate which of the two layers associated with the first SRS resource set the first PTRS should be mapped to, the second bit of the PTRS to UL layer mapping bit field is used to indicate which of the two layers associated with the second SRS resource set the second PTRS should be mapped to, the third bit of the PTRS to UL layer mapping bit field is used to indicate which of the two layers associated with the third SRS resource set the third PTRS should be mapped to, and the fourth bit of the PTRS to UL layer mapping bit field is used to indicate which of the two layers associated with the fourth SRS resource set the fourth PTRS should be mapped to. In one embodiment, the SRS resource set is changed to SRS resources.

[0126] Fig. 20 A method 2000 for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on an uplink according to an exemplary embodiment of the present disclosure is shown. The method includes receiving a message including a mapping parameter at 2010, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one of one or more codewords for uplink transmission of a reference signal. The one or more codewords may include a plurality of (e.g., two or more) codewords. The method further includes: allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table at 2020; and transmitting the PTRS through the allocated PTRS ports at 2030.

[0127] In some embodiments of method 2000, the number of entries in the mapping table is less than the number of configured uplink layers.

[0128] In some embodiments of the method 2000, the number of entries in the mapping table is equal to the number of configured uplink layers divided by the number of codewords used for uplink data transmission.

[0129] In some embodiments of method 2000, the number of PTRS ports is 1, and the entry in the mapping table is associated with a codeword having a highest modulation and coding scheme (MCS) among the one or more codewords.

[0130] In some embodiments of method 2000, the number of entries in the mapping table is equal to the maximum number of codewords in the configured uplink layer.

[0131] In some embodiments of method 2000, when the highest MCS is shared by two or more codewords of the one or more codewords, the entry in the mapping table is associated with the one of the two or more codewords having the lowest codeword index.

[0132] In some embodiments of method 2000, when the MCS is the same for one or more codewords, the entry in the mapping table is associated with the codeword having the lowest codeword index among the one or more codewords.

[0133] In some embodiments of method 2000, allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table includes: determining an uplink codeword with the highest MCS; and allocating PTRS to the uplink layer associated with the uplink codeword with the highest MCS.

[0134] In some embodiments of method 2000, the number of PTRS ports is n>1, and the entries in the mapping table are associated with n codewords having the highest MCS among the one or more codewords.

[0135] In some embodiments of method 2000, the number of entries in the mapping table is equal to the maximum number of codewords in the n uplink layers.

[0136] In some embodiments of method 2000, when two or more of the one or more codewords share a highest MCS, the entry in the mapping table is associated with a codeword having a lowest codeword index among the two or more codewords.

[0137] In some embodiments of method 2000, allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table includes: determining a codeword with a highest MCS; and allocating PTRS to the uplink layer associated with the codeword with the highest MCS.

[0138] In some embodiments of method 2000, the mapping parameters include a first part and a second part, the first part indicating which codewords of a plurality of codewords are associated with entries in a mapping table, and the second part indicating one or more uplink layers associated with the (one or more) codewords indicated by the first part.

[0139] In some embodiments of the method 2000, the mapping parameter comprises a bitmap indicating an uplink layer associated with each codeword of the plurality of codewords.

[0140] In some embodiments of the method 2000, the bitmap indicates the uplink layer associated with the first codeword and the second codeword having the highest modulation and coding scheme.

[0141] Fig.21 Another exemplary method 2100 for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on an uplink is shown. The method includes receiving a message including a mapping parameter at 2110, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one antenna panel of a plurality of antenna panels for uplink transmission of a reference signal. The method further includes: allocating one or more PTRS ports to corresponding uplink layers based on the indicated entries in the mapping table at 2120; and transmitting the PTRS through the allocated PTRS ports at 2130.

[0142] In some embodiments of method 2100, the mapping parameters include a first part and a second part, the first part indicating which antenna panels of a plurality of antenna panels are associated with an entry in a mapping table, and the second part indicating one or more uplink layers associated with the (one or more) antenna panels indicated by the first part.

[0143] In some embodiments of the method 2100, the second portion includes a bitmap that specifies an uplink layer for each antenna panel specified in the first portion.

[0144] In some embodiments of method 2100, the bitmap includes a single bit for each antenna panel that specifies the uplink layer associated with the antenna panel.

[0145] In some embodiments of the method 2100, the mapping parameters include a bitmap that indicates an uplink layer for each of the two or more antenna panels.

[0146] In some embodiments of method 2100, the antenna panel is specified by a sounding reference signal resource or a set of sounding reference signal resources.

[0147] In some embodiments of method 2100, when the wireless device is configured with two PTRS ports and is configured for STxMP operation, the first bit in the bitmap indicates an association between PTRS port 0 and (one or more) DMRS ports associated with the first TPMI / SRI field, and the second bit in the bitmap indicates an association between PTRS port 1 and (one or more) DMRS ports associated with the second TPMI / SRI field.

[0148] In some embodiments of method 2100, when the wireless device is configured with four PTRS ports and is configured for STxMP operation, the first bit in the bitmap indicates an association between PTRS port 0 and (one or more) DMRS ports associated with the first TPMI / SRI field, the second bit in the bitmap indicates an association between PTRS port 1 and (one or more) DMRS ports associated with the second TPMI / SRI field, and the third bit in the bitmap indicates an association between PTRS port 2 and (one or more) demodulation reference signal (DMRS) ports associated with the third TPMI / SRI field, and the fourth bit in the bitmap indicates an association between PTRS port 3 and (one or more) DMRS ports associated with the fourth TPMI / SRI field.

[0149] Fig. 22 Another exemplary method 2200 for transmitting PTRS implemented by a wireless device in a wireless communication system using multi-layer transmission on the uplink is shown. The method includes 2210 indicating to a network node the ability to map PTRS to an uplink layer based on reciprocity. The method further includes 2220 determining the strongest uplink layer based on reception of a downlink signal from the network node. The method further includes 2230 adapting the mapping between SRS ports or SRS resources so that the lowest SRS port index or the lowest SRS resource index is associated with the strongest uplink layer. The method further includes 2240 allocating PTRS to the strongest uplink layer without explicit signaling from the network node to indicate the uplink layer used for PTRS.

[0150] Fig.23 Another exemplary method 2300 for receiving PTRS implemented by a network node in a wireless communication system using multi-layer transmission on the uplink is shown. The method includes 2310 sending a message including a mapping parameter to a UE, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry in the mapping table is associated with at least one of one or more codewords for uplink transmission of a reference signal, and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The one or more codewords may include a plurality of (e.g., two or more) codewords. The method further includes 2320 receiving PTRS via the allocated PTRS port.

[0151] In some embodiments of method 2300, the number of entries in the mapping table is less than the number of configured uplink layers.

[0152] In some embodiments of the method 2300, the number of entries in the mapping table is equal to the number of configured uplink layers divided by the number of codewords used for uplink data transmission.

[0153] In some embodiments of method 2300, the number of PTRS ports is 1, and the entry in the mapping table is associated with a codeword having a highest modulation and coding scheme (MCS) among the one or more codewords.

[0154] In some embodiments of method 2300, the number of entries in the mapping table is equal to the maximum number of codewords in the configured uplink layer.

[0155] In some embodiments of method 2300, when the highest MCS is shared by two or more of the one or more codewords, the entry in the mapping table is associated with the one of the two or more codewords having the lowest codeword index.

[0156] In some embodiments of method 2300, when the MCS is the same for one or more codewords, the entry in the mapping table is associated with the codeword having the lowest codeword index among the one or more codewords.

[0157] In some embodiments of method 2300, when the number of PTRS ports is n>1, the entries in the mapping table are associated with n codewords having the highest MCS among the plurality of codewords.

[0158] In some embodiments of method 2300, the number of entries in the mapping table is equal to the maximum number of codewords in the n uplink layers.

[0159] In some embodiments of method 2300, when two codewords share the same MCS, the entry in the mapping table is associated with a codeword having a lowest codeword index among the plurality of codewords having a highest modulation and coding scheme (MCS).

[0160] In some embodiments of method 2300, the mapping parameters include a first part and a second part, the first part indicating which codewords of a plurality of codewords are associated with entries in a mapping table, and the second part indicating one or more uplink layers associated with the (one or more) codewords indicated by the first part.

[0161] In some embodiments of the method 2300, the mapping parameter comprises a bitmap indicating an uplink layer associated with each codeword in the plurality of codewords.

[0162] In some embodiments of the method 2300, the bitmap indicates the uplink layer associated with the first codeword and the second codeword having the highest modulation and coding scheme.

[0163] Fig.24Another exemplary method 2400 for receiving PTRS implemented by a network node in a wireless communication system using multi-layer transmission on the uplink is shown. The method includes 2410 sending a message including a mapping parameter to a UE, the mapping parameter having a value indicating one of a plurality of entries in a mapping table. Each entry is associated with at least one antenna panel of a plurality of antenna panels for uplink transmission of a reference signal and indicates an allocation of one or more PTRS ports to a corresponding uplink layer. The method further includes 2420 receiving PTRS through the allocated PTRS port.

[0164] In some embodiments of method 2400, the mapping parameters include a first part and a second part, the first part indicating which antenna panels of a plurality of antenna panels are associated with an entry in a mapping table, and the second part indicating one or more uplink layers associated with the (one or more) antenna panels indicated by the first part.

[0165] In some embodiments of method 2400, the second portion includes a bitmap that specifies an uplink layer for each antenna panel specified in the first portion.

[0166] In some embodiments of method 2400, the bitmap includes a single bit for each antenna panel that specifies the uplink layer associated with the antenna panel.

[0167] In some embodiments of the method 2400, the mapping parameters include a bitmap that indicates an uplink layer for each of the two or more antenna panels.

[0168] In some embodiments of method 2400, the antenna panel is specified by a sounding reference signal resource or a set of sounding reference signal resources.

[0169] In some embodiments of method 2400, when the wireless device is configured with two PTRS ports and is configured for STxMP operation, the first bit in the bitmap indicates an association between PTRS port 0 and (one or more) DMRS ports associated with the first TPMI / SRI field, and the second bit in the bitmap indicates an association between PTRS port 1 and (one or more) DMRS ports associated with the second TPMI / SRI field.

[0170] In some embodiments of method 2400, when the wireless device is configured with four PTRS ports and is configured for STxMP operation, the first bit in the bitmap indicates an association between PTRS port 0 and (one or more) DMRS ports associated with the first TPMI / SRI field, the second bit in the bitmap indicates an association between PTRS port 1 and (one or more) DMRS ports associated with the second TPMI / SRI field, and the third bit in the bitmap indicates an association between PTRS port 2 and (one or more) demodulation reference signal (DMRS) ports associated with the third TPMI / SRI field, and the fourth bit in the bitmap indicates an association between PTRS port 3 and (one or more) DMRS ports associated with the fourth TPMI / SRI field.

[0171] Fig.25 Another exemplary method 2500 of receiving PTRS implemented by a network node in a wireless communication system using multi-layer transmission on the uplink is shown. The method includes receiving an indication of a UE capability to map PTRS to an uplink layer based on reciprocity from a UE at 2510. The method further includes determining the strongest uplink layer at 2520. The method further includes receiving PTRS from the UE on the strongest uplink layer at 2530 without explicit signaling to the UE to indicate the uplink layer for PTRS.

[0172] The device can perform any of the methods described herein by implementing any functional component, module, unit or circuit. For example, in one embodiment, the device includes a corresponding circuit module or circuit configured to perform the steps shown in the method diagram. In this regard, the circuit module or circuit may include a circuit module dedicated to performing a certain functional processing and / or one or more microprocessors combined with a memory. For example, the circuit may include one or more microprocessors or microcontrollers, and other digital hardware, and other digital hardware may include a digital signal processor (DSP), dedicated digital logic, etc. The processing circuit may be configured to execute the program code stored in the memory, and the memory may include one or more types of memory, such as read-only memory (ROM), random access memory, cache memory, flash memory device, optical storage device, etc. In several embodiments, the program code stored in the memory may include program instructions for executing one or more telecommunications and / or data communication protocols, and instructions for implementing one or more of the technologies described herein. In an embodiment using a memory, the memory stores program code, and the program code, when executed by one or more processors, implements the technologies described herein.

[0173] Fig.26A UE 100 according to an exemplary embodiment is shown. The UE 100 generally includes one or more antenna panels 110 (each antenna panel includes multiple antennas or antenna elements 115), communication circuits 120 for communicating with a network via a wireless communication channel, processing circuits 130 for controlling the operation of the UE 100, and a memory 140 for storing programs and data required by the UE 100.

[0174] The communication circuit 120 is coupled to the antenna panel(s) 110 and includes the radio frequency circuitry required to communicate with the network through a wireless channel. The radio frequency circuitry may include an RF transmitter and an RF receiver configured to operate according to the 5G standard or other applicable standards.

[0175] The processing circuit 130 controls the overall operation of the UE 100. The processing circuit 130 may include one or more microprocessors, hardware, firmware, or a combination thereof. In a representative embodiment, the UE 100 is configured to execute Figure 20 to Figure 22 One or more of the methods.

[0176] The memory 140 includes both volatile memory and non-volatile memory for storing computer program code and data required for the processing circuit 130 to operate. The memory 140 may include any tangible, non-temporary computer-readable storage medium for storing data, including electronic, magnetic, optical, electromagnetic or semiconductor data storage devices. The memory 140 stores a computer program 150 including executable instructions, which configure the processing circuit 130 to implement one or more of the methods described herein. In this regard, the computer program 150 may include one or more code modules corresponding to the above-mentioned components or units. In general, computer program instructions and configuration information are stored in non-volatile memories such as ROM, erasable programmable read-only memory (EPROM) or flash memory. Temporary data generated during operation may be stored in volatile memories such as random access memory (RAM). In some embodiments, the computer program 150 for configuring the processing circuit 130 as described herein may be stored in a removable memory such as a portable compact disk, a portable digital video disk or other removable media. The computer program 150 may also be implemented in a carrier such as an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium. In one embodiment, the computer program 150 configures the processing circuit 130 to execute Figure 20 to Figure 22 One or more of those methods.

[0177] Fig. 27A base station 200 according to an exemplary embodiment is shown. The base station 200 generally includes one or more antenna panels 210 (each antenna panel includes multiple antennas or antenna elements 215), communication circuits 220 for communicating with a network via a wireless communication channel, processing circuits 230 for controlling the operation of the base station 200, and memory 240 for storing programs and data required by the base station 200.

[0178] The communication circuit 220 is coupled to the antenna panel 210 and includes the radio frequency circuits required to communicate with the network through a wireless channel. The radio frequency circuits may include an RF transmitter and an RF receiver configured to operate according to the 5G standard or other applicable standards.

[0179] Processing circuit 230 controls the overall operation of base station 200. Processing circuit 230 may include one or more microprocessors, hardware, firmware, or a combination thereof. In a representative embodiment, base station 200 is configured as a UDR, and processing circuit 230 is configured to perform Figure 23 to Figure 25 One or more of those methods.

[0180] The memory 240 includes both volatile memory and non-volatile memory for storing computer program code and data required for the operation of the processing circuit 230. The memory 240 may include any tangible, non-temporary computer-readable storage medium for storing data, including electronic, magnetic, optical, electromagnetic or semiconductor data storage devices. The memory 240 stores a computer program 250 including executable instructions, which configure the processing circuit 230 to implement one or more of the methods described herein. In this regard, the computer program 250 may include one or more code modules corresponding to the above-mentioned components or units. In general, computer program instructions and configuration information are stored in non-volatile memories such as ROM, erasable programmable read-only memory (EPROM) or flash memory. Temporary data generated during operation may be stored in volatile memories such as random access memory (RAM). In some embodiments, the computer program 250 for configuring the processing circuit 230 as described herein may be stored in a removable memory such as a portable compact disk, a portable digital video disk or other removable media. The computer program 250 may also be implemented in a carrier such as an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium. In one embodiment, the computer program 250 configures the processing circuit 230 to execute Figure 23 to Figure 25 One or more of those methods.

[0181] Those skilled in the art will also appreciate that the embodiments herein further include corresponding computer programs. The computer program includes instructions that, when executed on at least one processor of a device, cause the device to perform any of the above-mentioned corresponding processes. In this regard, the computer program may include one or more code modules corresponding to the above-mentioned components or units.

[0182] The embodiment further includes a carrier embodying such a computer program.Such a carrier may include one of an electronic signal, an optical signal, a radio signal or a computer-readable storage medium.

[0183] In this regard, embodiments herein also include a computer program product stored on a non-transitory computer-readable (storage or recording) medium and including instructions that, when executed by a processor of a device, cause the device to perform as described above.

[0184] The embodiments further include a computer program product including a program code portion for performing the steps of any of the embodiments herein when the computer program product is executed by a computing device. This computer program product may be stored on a computer readable recording medium.

Claims

1. A method (2000) for transmitting a phase tracking reference signal (PTRS) implemented by a wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the method comprising: receiving (2010) a message including a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry in the mapping table is associated with at least one codeword of one or more codewords used for uplink transmission of a reference signal; allocating (2020) one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table; and The PTRS is transmitted (2030) through the assigned PTRS port.

2. The method (2000) according to claim 1, wherein: The number of entries in the mapping table is less than the number of configured uplink layers.

3. The method (2000) according to claim 2, wherein: The number of entries in the mapping table is equal to the number of configured uplink layers divided by the number of codewords used for uplink data transmission.

4. The method (2000) according to claim 3, wherein: When the number of PTRS ports is 1, the entry in the mapping table is associated with a codeword having a highest modulation and coding scheme (MCS) among the one or more codewords.

5. The method (2000) according to claim 4, wherein: The number of entries in the mapping table is equal to the maximum number of codewords in the configured uplink layer.

6. The method (2000) according to claim 4 or 5, wherein: When the highest MCS is shared by two or more of the one or more codewords, the entry in the mapping table is associated with one of the two or more codewords having a lowest codeword index.

7. The method (2000) of claim 4, wherein: When the MCS is the same for the one or more codewords, the entry in the mapping table is associated with a codeword having a lowest codeword index among the one or more codewords.

8. The method (2000) according to any one of claims 4 to 7, wherein: Allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table includes: determining an uplink codeword having the highest MCS; and The PTRS is assigned to an uplink layer associated with the uplink codeword having the highest MCS.

9. The method (2000) of claim 4, wherein: When the number of PTRS ports is n>1, the entries in the mapping table are associated with n codewords having the highest MCS among the one or more codewords.

10. The method (2000) of claim 8, wherein: The number of entries in the mapping table is equal to the maximum number of codewords in the n uplink layers.

11. The method (2000) according to claim 8 or 10, wherein: When two or more of the one or more codewords share the highest MCS, the entry in the mapping table is associated with one of the two or more codewords having a lowest codeword index.

12. The method (2000) according to any one of claims 8 to 11, wherein: Allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table includes: determining a codeword having the highest MCS; and The PTRS is assigned to an uplink layer associated with the codeword having the highest MCS.

13. The method (2000) of claim 1, wherein: The mapping parameters include a first part that specifies which of a plurality of codewords are associated with the entry in the mapping table, and a second part that specifies one or more uplink layers associated with the one or more codewords specified by the first part.

14. The method (2000) of claim 1, wherein: The mapping parameters include a bitmap that indicates an uplink layer associated with each codeword of a plurality of codewords.

15. The method (2000) of claim 14, wherein: The bitmap indicates uplink layers associated with a first codeword and a second codeword having the highest modulation and coding scheme.

16. A method (2100) of transmitting a phase tracking reference signal (PTRS) implemented by a wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the method (2100) comprising: receiving (2110) a message including a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry in the mapping table is associated with at least one antenna panel of a plurality of antenna panels for uplink transmission of a reference signal; allocating (2120) one or more PTRS ports to a corresponding uplink layer based on the specified entry in the mapping table; The PTRS is transmitted (2130) through the assigned PTRS port.

17. The method (2100) of claim 16, wherein: The mapping parameters include a first part and a second part, wherein the first part indicates which antenna panels of a plurality of antenna panels are associated with the entry in the mapping table, and the second part indicates one or more uplink layers associated with the one or more antenna panels indicated by the first part.

18. The method (2100) of claim 17, wherein: The second portion includes a bitmap that specifies an uplink layer for each antenna panel specified in the first portion.

19. The method (2100) of claim 18, wherein: The bitmap includes a single bit for each antenna panel that specifies the uplink layer associated with the antenna panel.

20. The method (2100) of claim 16, wherein: The mapping parameters include a bitmap that indicates an uplink layer for each of the two or more antenna panels.

21. The method (2100) according to any one of claims 16-20, wherein: The antenna panel is indicated by a sounding reference signal resource or a sounding reference signal resource set.

22. The method (2100) of claim 15, wherein: When the wireless device (20, 100) is configured with two PTRS ports and is configured for simultaneous transmission from multiple panels (STxMP) operation, the first bit in the bitmap indicates an association between PTRS port 0 and one or more demodulation reference signal (DMRS) ports associated with a first transmit precoding matrix indicator (TPMI) / sounding reference signal (SRS) resource indicator (SRI) field, and the second bit in the bitmap indicates an association between PTRS port 1 and one or more DMRS ports associated with a second TPMI / SRI field.

23. The method (2100) of claim 15, wherein: When the wireless device (20, 100) is configured with four PTRS ports and is configured for simultaneous transmission from multiple panels (STxMP) operation, the first bit in the bitmap indicates an association between PTRS port 0 and one or more demodulation reference signal (DMRS) ports associated with a first transmit precoding matrix indicator (TPMI) / sounding reference signal (SRS) resource indicator (SRI) field, the second bit in the bitmap indicates an association between PTRS port 1 and one or more DMRS ports associated with a second TPMI / SRI field, and the third bit in the bitmap indicates an association between PTRS port 2 and one or more demodulation reference signal (DMRS) ports associated with a third TPMI / SRI field, and the fourth bit in the bitmap indicates an association between PTRS port 3 and one or more DMRS ports associated with a fourth TPMI / SRI field.

24. A method (2200) of transmitting a phase tracking reference signal (PTRS) implemented by a wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the method comprising: indicating (2210) to a network node (30, 200) a capability to map PTRS to an uplink layer based on reciprocity; determining (2220) the strongest uplink layer based on reception of a downlink signal from the network node (30, 200); Adapting (2230) a mapping between sounding reference signal (SRS) ports or SRS resources such that a lowest SRS port index or a lowest SRS resource index is associated with the strongest uplink layer; and The PTRS is assigned (2240) to the strongest uplink layer without explicit signaling from the network node (30, 200) to indicate the uplink layer to use for the PTRS.

25. A method (2300) implemented by a network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, receiving a phase tracking reference signal (PTRS), the method (2300) comprising: sending (2310) a message including a mapping parameter to a user equipment (UE), the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry is associated with at least one of one or more codewords for uplink transmission of a reference signal and indicates an assignment of one or more PTRS ports to a corresponding uplink layer; and The PTRS is received (2320) through the assigned PTRS port.

26. The method (2300) of claim 25, wherein: The number of entries in the mapping table is less than the number of configured uplink layers.

27. The method (2300) of claim 26, wherein: The number of entries in the mapping table is equal to the number of configured uplink layers divided by the number of codewords used for uplink data transmission.

28. The method (2300) of claim 27, wherein: When the number of PTRS ports is 1, the entry in the mapping table is associated with a codeword having a highest modulation and coding scheme (MCS) among the one or more codewords.

29. The method (2300) of claim 28, wherein: The number of entries in the mapping table is equal to the maximum number of codewords in the configured uplink layer.

30. The method (2300) of claim 28 or 29, wherein: When the highest MCS is shared by two or more of the one or more codewords, the entry in the mapping table is associated with one of the two or more codewords having a lowest codeword index.

31. The method (2300) of claim 28, wherein: When the MCS is the same for the one or more codewords, the entry in the mapping table is associated with a codeword having a lowest codeword index among the one or more codewords.

32. The method (2300) of claim 27, wherein: When the number of PTRS ports is n>1, the entries in the mapping table are associated with n codewords having the highest MCS among the multiple codewords.

33. The method (2300) of claim 32, wherein: The number of entries in the mapping table is equal to the maximum number of codewords in the n uplink layers.

34. The method (2300) of claim 32 or 33, wherein: When two codewords share the same MCS, the entry in the mapping table is associated with a codeword having a lowest codeword index among the plurality of codewords having the highest modulation and coding scheme (MCS).

35. The method (2300) of claim 25, wherein: The mapping parameters include a first part that specifies which of a plurality of codewords are associated with the entry in the mapping table, and a second part that specifies one or more uplink layers associated with the one or more codewords specified by the first part.

36. The method (2300) of claim 25, wherein: The mapping parameters include a bitmap that indicates an uplink layer associated with each codeword of a plurality of codewords.

37. The method (2300) of claim 36, wherein: The bitmap indicates uplink layers associated with a first codeword and a second codeword having the highest modulation and coding scheme.

38. A method (2400) implemented by a network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, receiving a phase tracking reference signal (PTRS), the method (2400) comprising: sending (2410) a message including a mapping parameter to a user equipment (UE) (20, 100), the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry is associated with at least one of a plurality of antenna panels for uplink transmission of a reference signal and indicates an assignment of one or more PTRS ports to a corresponding uplink layer; and The PTRS is received (2420) through the assigned PTRS port.

39. The method (2400) of claim 38, wherein: The mapping parameters include a first part and a second part, wherein the first part indicates which antenna panels of a plurality of antenna panels are associated with the entry in the mapping table, and the second part indicates one or more uplink layers associated with the one or more antenna panels indicated by the first part.

40. The method (2400) of claim 39, wherein: The second portion includes a bitmap that specifies an uplink layer for each antenna panel specified in the first portion.

41. The method (2400) of claim 40, wherein: The bitmap includes a single bit for each antenna panel that specifies the uplink layer associated with the antenna panel.

42. The method (2400) of claim 38, wherein: The mapping parameters include a bitmap that indicates an uplink layer for each of the two or more antenna panels.

43. The method (2400) of any one of claims 38-42, wherein: The antenna panel is indicated by a sounding reference signal resource or a sounding reference signal resource set.

44. The method (2400) of claim 38, wherein: When the wireless device (20, 100) is configured with two PTRS ports and is configured for simultaneous transmission from multiple panels (STxMP) operation, the first bit in the bitmap indicates an association between PTRS port 0 and one or more demodulation reference signal (DMRS) ports associated with a first transmit precoding matrix indicator (TPMI) / sounding reference signal (SRS) resource indicator (SRI) field, and the second bit in the bitmap indicates an association between PTRS port 1 and one or more DMRS ports associated with a second TPMI / SRI field.

45. The method (2400) of claim 38, wherein: When the wireless device (20, 100) is configured with four PTRS ports and is configured for simultaneous transmission from multiple panels (STxMP) operation, the first bit in the bitmap indicates an association between PTRS port 0 and one or more demodulation reference signal (DMRS) ports associated with a first transmit precoding matrix indicator (TPMI) / sounding reference signal (SRS) resource indicator (SRI) field, the second bit in the bitmap indicates an association between PTRS port 1 and one or more DMRS ports associated with a second TPMI / SRI field, and the third bit in the bitmap indicates an association between PTRS port 2 and one or more demodulation reference signal (DMRS) ports associated with a third TPMI / SRI field, and the fourth bit in the bitmap indicates an association between PTRS port 3 and one or more DMRS ports associated with a fourth TPMI / SRI field.

46. ​​A method (2500) implemented by a network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, receiving a phase tracking reference signal (PTRS), the method comprising: receiving (2510) from a user equipment (UE) an indication of a UE (20, 100) capability to map PTRS to an uplink layer based on reciprocity; determining (2520) the strongest uplink layer; and The PTRS is received (2530) from the UE (20, 100) on the strongest uplink layer without explicit signaling to the UE (20, 100) to indicate the uplink layer to use for PTRS.

47. A wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the wireless device (20, 100) being configured to transmit a phase tracking reference signal (PTRS), the wireless device (20, 100) being configured to: A message is received including a mapping parameter having a value that specifies one of a plurality of entries in a mapping table, wherein: Each entry in the mapping table is associated with at least one codeword of a plurality of codewords used for uplink transmission of a reference signal; allocating one or more PTRS ports to a corresponding uplink layer based on the specified entries in the mapping table; as well as The PTRS is transmitted through the assigned PTRS port.

48. The wireless device (20, 100) of claim 44, further configured to perform the method of any one of claims 2-15.

49. A wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the wireless device (20, 100) being configured to transmit a phase tracking reference signal (PTRS), the wireless device (20, 100) comprising: A communication circuit (120) for communicating with a network node (30, 200); as well as A processing circuit (130), wherein the processing circuit (130) is configured to: receiving a message including a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry in the mapping table is associated with at least one codeword of a plurality of codewords for uplink transmission of a reference signal; allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table; and The PTRS is transmitted through the assigned PTRS port.

50. The wireless device (20, 100) of claim 49, further configured to perform the method of any one of claims 2-15.

51. A wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the wireless device (20, 100) being configured to transmit a phase tracking reference signal (PTRS), the wireless device (20, 100) being configured to: A message is received including a mapping parameter having a value that specifies one of a plurality of entries in a mapping table, wherein: Each entry in the mapping table is associated with at least one antenna panel of a plurality of antenna panels used for uplink transmission of a reference signal; allocating one or more PTRS ports to a corresponding uplink layer based on the specified entries in the mapping table; as well as The PTRS is transmitted through the assigned PTRS port.

52. The wireless device (20, 100) of claim 51, further configured to perform the method of any one of claims 17-23.

53. A wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the wireless device (20, 100) being configured to transmit a phase tracking reference signal (PTRS), the wireless device (20, 100) comprising: A communication circuit (120) for communicating with a network node (30, 200); as well as A processing circuit (130), wherein the processing circuit (130) is configured to: receiving a message including a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry in the mapping table is associated with at least one antenna panel of a plurality of antenna panels for uplink transmission of a reference signal; allocating one or more PTRS ports to corresponding uplink layers based on the specified entries in the mapping table; and The PTRS is transmitted through the assigned PTRS port.

54. The wireless device (20, 100) of claim 53, further configured to perform the method of any one of claims 17-23.

55. A wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the wireless device (20, 100) being configured to transmit a phase tracking reference signal (PTRS), the wireless device (20, 100) being configured to: Indicating to a network node (30, 200) the ability to map PTRS to an uplink layer based on reciprocity; determining the strongest uplink layer based on reception of downlink signals from the network node (30, 200); Adapting a mapping between sounding reference signal (SRS) ports or SRS resources such that a lowest SRS port index or a lowest SRS resource index is associated with the strongest uplink layer; and The PTRS is assigned to the strongest uplink layer without explicit signaling from the network node (30, 200) to indicate the uplink layer to use for the PTRS.

56. A wireless device (20, 100) in a wireless communication system using multi-layer transmission on an uplink, the wireless device (20, 100) being configured to transmit a phase tracking reference signal (PTRS), the wireless device (20, 100) comprising: A communication circuit (120) for communicating with a network node (30, 200); as well as A processing circuit (130), wherein the processing circuit (130) is configured to: Indicating to a network node (30, 200) the ability to map PTRS to an uplink layer based on reciprocity; determining the strongest uplink layer based on reception of downlink signals from the network node (30, 200); Adapting a mapping between sounding reference signal (SRS) ports or SRS resources such that a lowest SRS port index or a lowest SRS resource index is associated with the strongest uplink layer; and The PTRS is assigned to the strongest uplink layer without explicit signaling from the network node (30, 200) to indicate the uplink layer to use for the PTRS.

57. A network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, the network node (30, 200) being configured to receive a phase tracking reference signal (PTRS) from a user equipment (UE), the network node (30, 200) being configured to: A message is sent to a user equipment (UE) including a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein: Each entry is associated with at least one of a plurality of codewords for uplink transmission of a reference signal and specifies an allocation of one or more PTRS ports to a corresponding uplink layer; as well as The PTRS is received through the assigned PTRS port.

58. The network node (30, 200) according to claim 57, further configured to perform the method of any of claims 26-37.

59. A network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, the network node (30, 200) being configured to receive a phase tracking reference signal (PTRS) from a user equipment (UE) (20, 100), the network node (30, 200) comprising: A communication circuit (220) for communicating with the UE (20, 100); as well as A processing circuit (230), wherein the processing circuit (230) is configured to: sending a message including a mapping parameter to a user equipment (UE), the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry is associated with at least one of a plurality of codewords for uplink transmission of a reference signal and indicates an assignment of one or more PTRS ports to a corresponding uplink layer; as well as The PTRS is received through the assigned PTRS port.

60. The network node (30, 200) of claim 59, further configured to perform the method of any of claims 26-37.

61. A network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, the network node (30, 200) being configured to receive a phase tracking reference signal (PTRS) from a user equipment (UE), the network node (30, 200) being configured to: A message is sent to a user equipment (UE) including a mapping parameter, the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein: Each entry is associated with at least one antenna panel of a plurality of antenna panels used for uplink transmission of a reference signal and specifies an assignment of one or more PTRS ports to a corresponding uplink layer; as well as The PTRS is received through the assigned PTRS port.

62. The network node (30, 200) according to claim 61, further configured to perform the method of any of claims 39-45.

63. A network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, the network node (30, 200) being configured to receive a phase tracking reference signal (PTRS) from a user equipment (UE), the network node (30, 200) comprising: A communication circuit (220) for communicating with the UE (20, 100); as well as A processing circuit (230), wherein the processing circuit (230) is configured to: sending a message including a mapping parameter to a user equipment (UE), the mapping parameter having a value indicating one of a plurality of entries in a mapping table, wherein each entry is associated with at least one antenna panel of a plurality of antenna panels for uplink transmission of a reference signal and indicates an assignment of one or more PTRS ports to a corresponding uplink layer; as well as The PTRS is received through the assigned PTRS port.

64. The network node (30, 200) according to claim 63, further configured to perform the method of any of claims 39-45.

65. A network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, the network node (30, 200) being configured to transmit a phase tracking reference signal (PTRS) from a user equipment (UE), the wireless device (20, 100) being configured to: receiving, from the UE, an indication of a UE (20, 100) capability to map PTRS to an uplink layer based on reciprocity; Determine the strongest uplink layer; as well as The PTRS is received from the UE on the strongest uplink layer without explicit signaling to the UE (20, 100) to indicate the uplink layer to use for PTRS.

66. A network node (30, 200) in a wireless communication system using multi-layer transmission on an uplink, the uplink being configured to transmit a phase tracking reference signal (PTRS), the wireless device (20, 100) comprising: A communication circuit (220) for communicating with a UE (20, 100); as well as A processing circuit (230), wherein the processing circuit (230) is configured to: receiving, from the UE, an indication of a UE (20, 100) capability to map PTRS to an uplink layer based on reciprocity; Determine the strongest uplink layer; as well as The PTRS is received from the UE on the strongest uplink layer without explicit signaling to the UE (20, 100) to indicate the uplink layer to use for PTRS.

67. A computer program (150) comprising executable instructions which, when executed by a processing circuit (130) in a user equipment (20, 100) in a wireless communication network (10), cause the user equipment to perform the method of any one of claims 1-24.

68. A carrier comprising the computer program (150) of claim 67, wherein: The carrier is one of an electronic signal, an optical signal, a radio signal or a computer-readable storage medium.

69. A non-transitory computer-readable storage medium (140) containing a computer program (150), the computer program (150) comprising executable instructions which, when executed by a processing circuit (130) in a user equipment (20, 100) in a wireless communication network (10), causes the user equipment to perform the method of any one of claims 1-24.

70. A computer program (250) comprising executable instructions which, when executed by processing circuitry in a network node (30, 200) in a wireless communication network (10), cause the network node (30, 200) to perform the method of any one of claims 25-46.

71. A carrier comprising the computer program (250) of claim 70, wherein: The carrier is one of an electronic signal, an optical signal, a radio signal or a computer-readable storage medium.

72. A non-transitory computer-readable storage medium (240) containing a computer program, the computer program comprising executable instructions which, when executed by a processing circuit in a network node (30, 200) in a wireless communication network (10), cause the network node (30, 200) to perform the method of any one of claims 25-46.

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