Demodulation method, and device

Abstract

The present application relates to a demodulation method, and a device. The demodulation method comprises: a terminal device determining K activated CDM groups, K being a positive integer; the terminal device receiving first DCI signaling from a network device, and determining, according to the first DCI signaling, a DMRS port, in a CDM group, that is used for a PDSCH; and the terminal device demodulating the PDSCH on the basis of the DMRS port, in the CDM group, that is used for the PDSCH. In the embodiments of the present application, a DMRS port, in a CDM group, that is used for a PDSCH is indicated by means of DCI signaling, such that a method for simultaneous transmission of a plurality of nodes can be supported, and thus a throughput of downlink transmission can be improved.

Description

Demodulation method and device Technical Field

[0001] The present application relates to the field of communications, and more specifically, to a demodulation method and device. Background Art

[0002] In the NR system, the demodulation reference signal (DMRS) is designed to support up to 2 or 3 code division multiplexing (CDM) groups and can only support the joint transmission of two transmission reception points (TRP). However, in future systems such as cell-free systems, the base station will be replaced by a large number of sub-nodes, each of which only supports a small number of ports (such as 1, 2 or 4 ports) and transmission layers, and multiple nodes can transmit data to terminal devices at the same time. Since each sub-node requires a corresponding CDM group, the number of CDM groups in the existing DMRS is insufficient to support the joint transmission of a large number of sub-nodes, and the DMRS port indication in the existing downlink control information (DCI signaling) is also unable to support a large number of CDM groups. Due to the inability to support the joint transmission of a large number of sub-nodes, the downlink transmission throughput is low.

[0003] Summary of the Invention

[0004] The embodiments of the present application provide a demodulation method and device, which can improve the throughput of downlink transmission.

[0005] This embodiment of the present application provides a demodulation method, including:

[0006] The terminal device determines K activated CDM groups, where K is a positive integer;

[0007] The terminal device receives a first DCI signaling from a network device, and determines a DMRS port for a PDSCH in the CDM group according to the first DCI signaling;

[0008] The terminal device demodulates the PDSCH based on the DMRS port used for the PDSCH in the CDM group.

[0009] An embodiment of the present application provides a signal transmission method, including:

[0010] The network device determines K activated CDM groups, where K is a positive integer;

[0011] The network device sends a first DCI signaling, where the first DCI signaling is used to determine a DMRS port for the PDSCH in the CDM group.

[0012] An embodiment of the present application provides a terminal device, including:

[0013] A first determining unit, configured to determine K activated CDM groups, where K is a positive integer;

[0014] A second determining unit is configured to receive a first DCI signaling from a network device, and determine a DMRS port for the PDSCH in the CDM group according to the first DCI signaling;

[0015] The demodulation unit is configured to demodulate the PDSCH based on the DMRS port used for the PDSCH in the CDM group.

[0016] An embodiment of the present application provides a network device, including:

[0017] a third determining unit, configured to determine K activated CDM groups, where K is a positive integer;

[0018] A sending unit is configured to send a first DCI signaling, where the first DCI signaling is used to determine a DMRS port for a PDSCH in the CDM group.

[0019] An embodiment of the present application provides a communication device, comprising: a processor, a memory, and a transceiver, wherein the memory is used to store a computer program, the processor is used to call and run the computer program stored in the memory, and control the transceiver so that the communication device executes the above method.

[0020] The embodiment of the present application provides a chip for implementing the above method.

[0021] Specifically, the chip includes: a processor, which is used to call and run a computer program from a memory, so that a device equipped with the chip executes the above method.

[0022] An embodiment of the present application provides a computer-readable storage medium for storing a computer program, which enables a device to perform the above-mentioned method when the computer program is executed by the device.

[0023] An embodiment of the present application provides a computer program product, including computer program instructions, which enable a computer to execute the above method.

[0024] An embodiment of the present application provides a computer program, which, when executed on a computer, enables the computer to execute the above method.

[0025] The embodiment of the present application activates multiple CDM groups for the terminal device and uses DCI signaling to indicate the DMRS ports used for PDSCH in each CDM group, so that the terminal device can determine the multiple activated CDM groups and the DMRS ports used for PDSCH in each CDM group, and demodulate PDSCH based on the DMRS ports used for PDSCH in each CDM group, thereby supporting simultaneous transmission to multiple nodes and improving the throughput of downlink transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic diagram of an application scenario according to an embodiment of the present application.

[0027] FIG2A is a schematic diagram of a type 1 single-symbol DMRS.

[0028] FIG2B is a schematic diagram of a type 1 dual-symbol DMRS.

[0029] FIG2C is a schematic diagram of a type 2 single-symbol DMRS.

[0030] FIG2D is a schematic diagram of a type 2 dual-symbol DMRS.

[0031] FIG3A is a schematic diagram of a PDCCH-based downlink non-coherent transmission system.

[0032] FIG3B is a schematic diagram of the structure of a decellularized system.

[0033] FIG4 is a schematic flowchart of a demodulation method 400 according to an embodiment of the present application.

[0034] FIG5A is a first schematic diagram of a DMRS according to an embodiment of the present application.

[0035] FIG5B is a second schematic diagram of a DMRS according to an embodiment of the present application.

[0036] FIG5C is a third schematic diagram of a DMRS according to an embodiment of the present application.

[0037] FIG5D is a fourth schematic diagram of a DMRS according to an embodiment of the present application.

[0038] FIG6 is a schematic flowchart of a signal sending method 600 according to an embodiment of the present application.

[0039] FIG7 is a schematic block diagram of a terminal device 700 according to an embodiment of the present application.

[0040] FIG8 is a schematic block diagram of a network device 800 according to an embodiment of the present application.

[0041] FIG9 is a schematic block diagram of a communication device according to an embodiment of the present application.

[0042] FIG10 is a schematic block diagram of a chip according to an embodiment of the present application.

[0043] FIG11 is a schematic block diagram of a communication system according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0045] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Global System of Mobile communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, Advanced Long Term Evolution (LTE-A) system, New Radio (NR) system, NR system evolution system, LTE on unlicensed spectrum (LTE-U) system, NR on unlicensed spectrum (NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (Wireless Fidelity) system. Fidelity, WiFi), fifth-generation communication (5th-Generation, 5G) system or other communication systems, etc.

[0046] Generally speaking, traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communications, but will also support, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, or vehicle-to-everything (V2X) communication, etc. The embodiments of the present application can also be applied to these communication systems.

[0047] In one embodiment, the communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, and a standalone (SA) networking scenario.

[0048] In one embodiment, the communication system in the embodiment of the present application can be applied to an unlicensed spectrum, wherein the unlicensed spectrum can also be considered as a shared spectrum; or, the communication system in the embodiment of the present application can also be applied to an authorized spectrum, wherein the authorized spectrum can also be considered as an unshared spectrum.

[0049] The embodiments of the present application describe various embodiments in conjunction with network devices and terminal devices, wherein the terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

[0050] The terminal device can be a station (STAION, ST) in a WLAN, a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a next-generation communication system such as an NR network, or a terminal device in a future evolved Public Land Mobile Network (PLMN) network, etc.

[0051] In an embodiment of the present application, the terminal device can be deployed on land, including indoors or outdoors, handheld, wearable or vehicle-mounted; it can also be deployed on the water surface (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.).

[0052] In an embodiment of the present application, the terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home, etc.

[0053] As an example and not a limitation, in the embodiment of the present application, the terminal device may also be a wearable device. Wearable devices may also be called wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0054] In an embodiment of the present application, the network device may be a device for communicating with a mobile device. The network device may be an access point (AP) in WLAN, a base station (BTS) in GSM or CDMA, a base station (NodeB, NB) in WCDMA, an evolved base station (eNB or eNodeB) in LTE, or a relay station or access point, or a vehicle-mounted device, a wearable device, and a network device (gNB) in an NR network, or a network device in a future evolved PLMN network or a network device in an NTN network, etc.

[0055] In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0056] FIG1 exemplarily illustrates a communication system 100. The communication system includes a network device 110 and two terminal devices 120. In one embodiment, the communication system 100 may include multiple network devices 110, and each network device 110 may include a different number of terminal devices 120 within its coverage area, which is not limited in this embodiment of the present application.

[0057] In one embodiment, the communication system 100 may further include other network entities such as a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF), which is not limited in this embodiment of the present application.

[0058] Among them, the network equipment may include access network equipment and core network equipment. That is, the wireless communication system also includes multiple core networks for communicating with the access network equipment. The access network equipment can be an evolutionary base station (evolutional node B, abbreviated as eNB or e-NodeB) macro base station, micro base station (also called "small base station"), pico base station, access point (AP), transmission point (TP) or new generation base station (new generation Node B, gNodeB), etc. in a long-term evolution (LTE) system, a next-generation (mobile communication system) (next radio, NR) system or an authorized auxiliary access long-term evolution (LAA-LTE) system.

[0059] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system shown in Figure 1 as an example, the communication device may include a network device and a terminal device having a communication function. The network device and the terminal device may be specific devices in the embodiments of the present application and will not be described in detail here. The communication device may also include other devices in the communication system, such as a network controller, a mobility management entity, and other network entities, which are not limited in the embodiments of the present application.

[0060] It should be understood that the terms "system" and "network" are often used interchangeably herein. The term "and / or" is simply a description of an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " generally indicates that the related objects are in an "or" relationship.

[0061] It should be understood that the "indication" mentioned in the embodiments of this application can be a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" can mean that A directly indicates B, for example, B can be obtained through A; it can also mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; it can also mean that there is an association between A and B.

[0062] In the description of the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and being indicated, configuration and being configured, etc.

[0063] To facilitate understanding of the technical solutions of the embodiments of the present application, the relevant technologies of the embodiments of the present application are described below. The following relevant technologies can be arbitrarily combined with the technical solutions of the embodiments of the present application as optional solutions, and they all fall within the protection scope of the embodiments of the present application.

[0064] 1. Introduction to NR DMRS:

[0065] In the New Radio (NR) system, the demodulation reference signal (DMRS) can be divided into a pre-DMRS and a post-DMRS. The pre-DMRS is usually located in the first few orthogonal frequency division multiplexing (OFDM) symbols of the time slot, and the post-DMRS is a repetition of the pre-DMRS to ensure performance in high-speed scenarios. The pre-DMRS can contain one or two OFDM symbols and is configured by the network equipment. The position of the post-DMRS is fixed relative to the position of the pre-DMRS.

[0066] NR supports two DMRS types: Type 1 and Type 2. Different types of DMRS occupy resources in different ways.

[0067] Figures 2A and 2B are schematic diagrams of type 1 single-symbol DMRS and dual-symbol DMRS, respectively. Two code division multiplexing (CDM) groups (different patterns represent different CDM groups) can be supported on one OFDM symbol in each physical resource block (PRB). Each CDM group contains six subcarriers. Each CDM group can support two ports, which are orthogonalized by an orthogonal cover code (OCC). That is, the OCC code used by one port on different subcarriers is [+1+1+1+1+1+1], and the OCC code used by the other port on different subcarriers is [+1-1+1-1+1-1]. In this way, Type 1 DMRS can support up to 4 orthogonal ports on one OFDM symbol and up to 8 orthogonal ports on two OFDM symbols (Time Domain-Orthogonal Cover Code (TD-OCC) is used between the two OFDM symbols). Specifically, the first CDM group of the first DMRS symbol includes ports {1000, 1001}, and the second CDM group includes ports {1002, 1003}; the first CDM group of the second DMRS symbol includes ports {1004, 1005}, and the second CDM group includes ports {1006, 1007}. In Figure 2A, 2 CDM groups are supported on the third OFDM symbol of the PRB; in Figure 2B, 2 CDM groups are supported on the third OFDM symbol and the fourth OFDM symbol of the PRB; the positions of the OFDM symbols supporting the CDM groups can be fixed.

[0068] Figures 2C and 2D are schematic diagrams of type 2 single-symbol DMRS and dual-symbol DMRS, respectively. Three CDM groups (different patterns represent different CDM groups) can be supported on one OFDM symbol in each PRB, and each CDM group contains four adjacent subcarriers. Each CDM group can support two ports, and the two ports are orthogonalized by OCC, that is, the OCC code used by one port on different subcarriers is [+1+1+1+1], and the OCC code used by the other port on different subcarriers is [+1-1+1-1]. In this way, type 2 DMRS can support up to 6 orthogonal ports on one OFDM symbol and up to 12 orthogonal ports on two OFDM symbols. Specifically, the first CDM group of the first DMRS symbol includes ports {1000, 1001}, the second CDM group includes ports {1002, 1003}, and the third CDM group includes ports {1004, 1005}; the first CDM group of the second DMRS symbol includes ports {1006, 1007}, the second CDM group includes ports {1008, 1009}, and the third CDM group includes ports {1010, 1011}. In Figure 2C, three CDM groups are supported on the third OFDM symbol of the PRB; in Figure 2D, three CDM groups are supported on the third and fourth OFDM symbols of the PRB; the positions of the OFDM symbols supporting CDM groups can be fixed.

[0069] The DMRS ports within a CDM group are kept orthogonal by code division multiplexing, and different CDM groups are kept orthogonal by time division multiplexing (TDM) or frequency division multiplexing (FDM).

[0070] 2. Non-Coherent Joint Transmission (NCJT) based on Multiple Transmission and Reception Point (Multi-TRP):

[0071] Downlink non-coherent joint transmission based on Multi-TRP is introduced in the NR system. Figure 3A is a schematic diagram of a downlink non-coherent transmission system based on the physical downlink control channel (PDCCH). In downlink non-coherent transmission, the same downlink control information (DCI signaling) can be used to schedule data transmission of multiple different TRPs, wherein the data of different TRPs use different transmission layers. Among them, the network device can indicate up to two CDM groups, and the transmission layers from different TRPs use DMRS ports in different CDM groups for demodulation. Furthermore, the network device can be configured with up to two TCI states, and the transmission layers of different TRPs use different TCI states. Among them, the indication of the CDM group is realized through the DMRS port indication in the DCI signaling. The network device needs to indicate the DMRS ports from the two CDM groups and two TCI states in one DCI signaling. Each CDM group corresponds to one TCI state, thereby supporting different CDM groups to use different beams for transmission on different TRPs. In this case, the Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) feedback can reuse the mechanism in the existing protocol. In addition, the terminal must report the Rank Indication (RI) and Precoding Matrix Indicator (PMI) corresponding to different TRPs in a single CSI, as well as a joint Channel Quality Indicator (CQI) (used to determine the Modulation and Coding Scheme (MCS)).

[0072] TYPE 1 and TYPE 2 DMRS can support up to 2 or 3 CDM groups and can only support the joint transmission of two TRPs. However, in systems such as cell-free systems, the base station will be replaced by a large number of sub-nodes. Figure 3B is a structural diagram of a cell-free system. In a cell-free system, multiple sub-nodes are included, and the base station will be replaced by a large number of sub-nodes. Each sub-node only supports a small number of ports (such as 1, 2 or 4 ports) and transmission layers, but multiple nodes can transmit data to the terminal device at the same time. For example, the network side can simultaneously schedule 6 or even more sub-nodes to transmit data to the terminal at the same time, thereby supporting more transmission layers through space division multiplexing and improving the system throughput. Since each sub-node requires a corresponding CDM group, the number of CDM groups in the existing DMRS is insufficient to support the joint transmission of a large number of nodes, and the DMRS port indication and transmission control information (Transceiver Control Interface, TCI) status indication in the existing downlink control information (DCI signaling) cannot support the indication of a large number of CDM groups and TCI status. For example, existing DCI signaling directly uses a table to indicate the DMRS ports to be used and the CDM groups to be rate-matched. These DMRS ports can come from up to two CDM groups. However, if the number of CDM groups and the number of possible DMRS ports to be used increases significantly, the number of possible combinations of CDM groups and DMRS ports will be too numerous to be covered using a table, and thus this method will become unusable.

[0073] FIG4 is a schematic flow chart of a demodulation method 400 according to an embodiment of the present application. The method 400 can be applied to the systems shown in FIG1-3 , but is not limited thereto. The method includes at least part of the following contents.

[0074] S410. The terminal device determines K activated CDM groups, where K is a positive integer.

[0075] S420: The terminal device receives DCI signaling from the network device, and determines a DMRS port for a physical downlink shared channel (PDSCH) in the CDM group according to the DCI signaling.

[0076] S430: The terminal device demodulates the PDSCH based on the DMRS port used for the PDSCH in the CDM group.

[0077] In an embodiment of the present application, the DMRS ports within a CDM group are maintained orthogonal by code division multiplexing (CDM) (e.g., by orthogonal DMRS sequences or OCC codes), and different CDM groups are maintained orthogonal by time division multiplexing (TDM) or frequency division multiplexing (FDM) (i.e., by different physical resources). In other words, the design of the CDM group in the embodiment of the present application is not necessarily the same as the DMRS design of the NR system, and it only needs to meet the above conditions.

[0078] K may be an integer greater than 3. For example, the terminal device determines, based on an instruction from the network device, K (K is greater than 3) activated CDM groups, each of which includes N DMRS ports. N is a positive integer, such as 2, 4, or another positive integer.

[0079] The terminal device can use a variety of methods to determine the K activated CDM groups. In some embodiments, the number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured for the network device. In some examples, the terminal device determines the K activated CDM groups from the L CDM groups agreed with the network device, where L is an integer greater than or equal to 3. For example, the terminal device has pre-agreed with the network device on L CDM groups, including CDM group 1, CDM group 2, ..., CDM group L; the terminal device can determine, from the L CDM groups, that K of the CDM groups are activated CDM groups. If K = L, all pre-agreed CDM groups are activated CDM groups.

[0080] Methods for determining the K activated CDM groups include at least the following:

[0081] Method 1:

[0082] The terminal device can receive high-layer signaling from the network device and determine the activated CDM group based on the high-layer signaling.

[0083] For example, high-level signaling may indicate a bitmap, where each bit in the bitmap corresponds to a CDM group, and the bit indicates whether the corresponding CDM group is an activated CDM group. The CDM group corresponding to the bit with a value of 1 is an activated CDM group, and the CDM group corresponding to the bit with a value of 0 is an inactivated CDM group. Alternatively, the CDM group corresponding to the bit with a value of 0 is an activated CDM group, and the CDM group corresponding to the bit with a value of 1 is an inactivated CDM group. The terminal device receives the bitmap indicated by the high-level signaling, and determines whether the corresponding CDM group is an activated CDM group based on each bit in the bitmap.

[0084] For another example, high-layer signaling may indicate the number K of activated CDM groups. The terminal device receives K indicated by the high-layer signaling and determines K activated CDM groups. For example, the terminal device may determine that the 1st to Kth CDM groups among the L CDM groups are activated CDM groups; or, the terminal device may determine that the last K CDM groups among the L CDM groups are activated CDM groups; or, the terminal device may adopt other rules to determine K CDM groups from the L CDM groups as activated CDM groups. This application does not limit the specific rules. That is, the high-layer signaling configures the value of K, and the terminal device determines the activated CDM group from the pre-agreed L CDM groups.

[0085] For another example, high-layer signaling can indicate the number of DMRS symbols. The terminal device receives the number of DMRS symbols indicated by the high-layer signaling and determines that the CDM group on the DMRS symbol corresponding to the number of DMRS symbols is an activated CDM group. In other words, the high-layer signaling configures the number S of DMRS symbols. According to the pre-agreed agreement between the terminal device and the network device, the terminal device can determine that the CDM group on the S DMRS symbols is an activated CDM group. The positions of the S DMRS symbols are pre-agreed between the terminal device and the network device.

[0086] For another example, the terminal device can receive radio resource control (RRC) signaling and media access control (MAC) control element (CE) from the network device, wherein the RRC signaling is used to indicate the number S of DMRS symbols, and the MAC CE is used to indicate the CDM group activated on the S DMRS symbols. The terminal device can determine the number S of DMRS symbols based on the RRC signaling, and according to the pre-agreed agreement between the terminal device and the network device, can determine the CDM group on the S DMRS symbols as the activated CDM group; and the terminal device can determine the CDM group activated on the S DMRS symbols based on the MAC CE. The positions of the S DMRS symbols are pre-agreed between the terminal device and the network device. That is, the RRC signaling configures the number S of DMRS symbols, and the MAC CE indicates the activated CDM group from the CDM groups on the S DMRS symbols, and the activation of the CDM group is completed through the combination of these two signalings.

[0087] Method 2:

[0088] The terminal device receives DCI signaling from the network device and determines the activated CDM group based on the DCI signaling.

[0089] For example, the DCI signaling may indicate a bitmap, where each bit in the bitmap corresponds to a CDM group, and the bit indicates whether the corresponding CDM group is an activated CDM group. The CDM group corresponding to the bit with a value of 1 is an activated CDM group, and the CDM group corresponding to the bit with a value of 0 is an inactivated CDM group. Alternatively, the CDM group corresponding to the bit with a value of 0 is an activated CDM group, and the CDM group corresponding to the bit with a value of 1 is an inactivated CDM group. The terminal device receives the bitmap indicated by the DCI signaling, and determines whether the corresponding CDM group is an activated CDM group based on each bit in the bitmap.

[0090] For another example, the DCI signaling may indicate the number of activated CDM groups K. The terminal device receives the number of DMRS symbols indicated by the DCI signaling, and determines that the CDM group on the DMRS symbol corresponding to the number of DMRS symbols is the activated CDM group. For example, the terminal device may determine that the 1st to Kth CDM groups among the L CDM groups are activated CDM groups; or, the terminal device may determine that the last K CDM groups among the L CDM groups are activated CDM groups; or, the terminal device may adopt other rules to determine K CDM groups from the L CDM groups as activated CDM groups. This application does not limit the specific rules. That is, the high-level signaling configures the value of K, and the terminal device determines the activated CDM group from the pre-agreed L CDM groups.

[0091] For another example, DCI signaling can indicate the number of DMRS symbols. The terminal device receives the number of DMRS symbols indicated by the DCI signaling and determines that the CDM group on the DMRS symbol corresponding to the number of DMRS symbols is an activated CDM group. In other words, the high-level signaling configures the number S of DMRS symbols. Based on the pre-agreed agreement between the terminal device and the network device, the terminal device can determine that the CDM groups on the S DMRS symbols are all activated CDM groups. The positions of the S DMRS symbols are pre-agreed between the terminal device and the network device.

[0092] For another example, the number of DMRS symbols is indicated by RRC signaling, and the CDM group activated on the DMRS symbol corresponding to the number of DMRS symbols is indicated by DCI signaling. The terminal device receives RRC signaling and DCI signaling from the network device. The terminal device can determine the number of DMRS symbols S according to the RRC signaling, and according to the pre-agreed agreement between the terminal device and the network device, the CDM group on the S DMRS symbols can be determined as the activated CDM group; and the terminal device can determine the CDM group activated on the S DMRS symbols according to the DCI signaling. The positions of the S DMRS symbols are pre-agreed between the terminal device and the network device. In other words, RRC signaling configures the number S of DMRS symbols, and DCI signaling indicates the activated CDM group from the CDM groups on these S DMRS symbols, and the activation of the CDM group is completed by the combination of these two signalings.

[0093] Method 3:

[0094] The terminal device determines the number of activated CDM groups based on the maximum number of transmission layers configured by the network device, and determines the activated CDM groups based on the number.

[0095] Method 4:

[0096] The terminal device determines the number of activated CDM groups based on the number of TCI states indicated in the DCI signaling, and determines the activated CDM groups based on the number of activated CDM groups.

[0097] The terminal device uses any of the above methods to determine the multiple activated CDM groups, and based on the received DCI signaling, the terminal device can determine the DMRS port corresponding to each CDM group in the multiple activated CDM groups. Each CDM group can be transmitted by a transmission node, so it can support simultaneous transmission of multiple nodes and improve the throughput of downlink transmission.

[0098] In some embodiments, DCI signaling may indicate the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups. Based on the DCI signaling, the terminal device may determine the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups; and determine the DMRS port for PDSCH in each CDM group in the K CDM groups based on the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups. There are at least three ways in which DCI signaling indicates the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups:

[0099] Method 1:

[0100] The DCI signaling may include a first information field, where the first information field indicates the number of PDSCH transmission layers corresponding to each of the K CDM groups;

[0101] Correspondingly, the terminal device can determine the number of PDSCH transmission layers corresponding to each of the K CDM groups based on the first information field.

[0102] For example, a correspondence between different values ​​of an index and different combinations of PDSCH transmission layers may be predefined, where the PDSCH transmission layer combination specifies the number of PDSCH transmission layers corresponding to each CDM group. The first information field may indicate the value of the index; the terminal device determines the number of PDSCH transmission layers corresponding to each of the K CDM groups based on the value of the index and the predefined correspondence.

[0103] The number of PDSCH transmission layers corresponding to each CDM group can be in the range of {1,2}, or {0,1,2}, or {1,2,3,4}, or {0,1,2,3,4}, or {0,1,2,NULL}, or {0,1,2,3,NULL}. The number of PDSCH transmission layers corresponding to each CDM group can be any value in the range.

[0104] 0 may indicate that the CDM group is not used to send DMRS, but the terminal device needs to perform rate matching on the resources occupied by the CDM group;

[0105] NULL may indicate that the CDM group is not used to send DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0106] 1, 2, 3 and 4 may indicate that the number of PDSCH transmission layers corresponding to the CDM group is 1, 2, 3 and 4, respectively.

[0107] Here, 0 and Null can also use other description methods to indicate the same meaning. For example, the physical meanings expressed by the two can be interchangeable. That is, NULL can indicate that the CDM group is not used to send DMRS, but the terminal device needs to perform rate matching on the resources occupied by the CDM group; 0 can indicate that the CDM group is not used to send DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0108] The above representation is only an example. The embodiment of the present application may also use other methods to represent the value range of the number of PDSCH transmission layers corresponding to the CDM group, which will not be enumerated here.

[0109] Method 2:

[0110] The DCI signaling includes a second information field and a third information field, wherein the second information field indicates the value of K (K is the number of activated CDM groups), and the third information field indicates a combination of K transmission layer numbers corresponding to the value of K; each transmission layer number in the combination is the transmission layer number corresponding to one CDM group in the K CDM groups.

[0111] Alternatively, the second information field may be indicated through higher layer signaling (such as MAC CE), and the third information field may be indicated through DCI signaling.

[0112] Accordingly, the terminal device can determine the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups based on the value of K indicated by the second information field and the combination of the number of K transmission layers corresponding to the value of K indicated by the third information field.

[0113] For example, for different values ​​of K, a correspondence between different values ​​of an index and different combinations of PDSCH transmission layers can be pre-specified. The PDSCH transmission layer combination specifies the number of PDSCH transmission layers corresponding to each CDM group. The third information field can indicate the value of the index. The terminal device first determines the corresponding relationship to be adopted based on the value of K indicated by the second information field; then, based on the corresponding relationship and the value of the index indicated by the third information field, determines the number of PDSCH transmission layers corresponding to each of the K CDM groups.

[0114] Method 3:

[0115] DCI signaling indicates the total number of transmission layers and how the transmission layers are allocated among the K activated CDM groups.

[0116] Accordingly, the terminal device may determine the number of PDSCH transmission layers corresponding to each of the K CDM groups according to the total number of transmission layers and the manner in which the transmission layers are allocated in the K CDM groups.

[0117] For example, a correspondence between different values ​​of an index and different transmission layer allocation methods can be specified, where the transmission layer allocation method specifies the number of PDSCH transmission layers corresponding to each CDM group. The DCI signaling can indicate the value of the index. The terminal device determines the number of PDSCH transmission layers corresponding to each of the K CDM groups based on the correspondence and the value of the index indicated by the DCI signaling.

[0118] For example, the number of activated CDM groups K = 4, the total number of transmission layers indicated in the DCI signaling is 5, and the 5 transmission layers are allocated in the 4 activated CDM groups as {2, 1, 1, 1}, that is, the number of transmission layers corresponding to the first activated CDM group is 2, and the number of transmission layers corresponding to the remaining activated CDM groups is 1.

[0119] In one example, the terminal device may only determine the number of transmission layers corresponding to the k CDM groups actually used for PDSCH DMRS transmission among the K activated CDM groups (k is less than or equal to K); the number of transmission layers corresponding to the other CDM groups among the K activated CDM groups defaults to 0, that is, not used for PDSCH DMRS transmission. For example, the allocation method of the transmission layer among the K CDM groups includes: a combination of k transmission layer numbers; where k is a positive integer less than or equal to K; where,

[0120] The k transmission layers correspond to the first k CDM groups among the K CDM groups; or

[0121] The k transmission layer numbers correspond to the k CDM groups indicated by the network devices in the K CDM groups.

[0122] In addition, among the k transmission layers, the difference between the maximum number of transmission layers corresponding to the CDM group and the minimum number of transmission layers is less than or equal to 1; or, among the k transmission layers, the difference between the maximum number of transmission layers and the minimum number of transmission layers is less than or equal to 2.

[0123] It can be seen that when the transmission layers are distributed among k CDM groups, the maximum difference between the number of transmission layers corresponding to different CDM groups does not exceed 1 or 2, thereby ensuring a relatively balanced distribution of the number of transmission layers among different CDM groups; when applied to multi-point transmission scenarios, it can ensure that the difference in the number of transmission layers between multiple nodes is small, and thus ensure that the difference in channel gain between multiple nodes is small, which is suitable for multi-point transmission.

[0124] After determining the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups using any of the above methods, the terminal device can determine the DMRS ports used for PDSCH in each of the K CDM groups based on the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups. For example, when the number of PDSCH transmission layers corresponding to a CDM group is n, where n is a positive integer; the terminal device determines that the n PDSCH transmission layers of the CDM group use the first n DMRS ports in the CDM group; or, the terminal device determines the n DMRS ports used for the n PDSCH transmission layers in the CDM group based on high-layer signaling or physical layer signaling instructions.

[0125] In other implementations, the DCI signaling may respectively indicate the DMRS port used for PDSCH in each of the K CDM groups. Based on the DCI signaling, the terminal device may directly determine the DMRS port used for PDSCH in each of the K CDM groups.

[0126] For example, the DCI signaling indicates the DMRS port used for PDSCH in each of the K CDM groups. Accordingly, according to the DCI signaling, the terminal device can determine the DMRS port used for PDSCH in each of the K CDM groups.

[0127] The value range of the DMRS port for PDSCH in each CDM group may be {0, 1, 0-1}, or {0, 1, 0-1, Null}, or {0, 1, 2, 3, 0-1, 2-3, 0-2, 0-3}, or {0, 1, 2, 3, 0-1, 2-3, 0-2, 0-3, Null}. Among them, NULL can indicate that the CDM group is not used to send DMRS for terminal equipment, that is, there is no DMRS port for PDSCH in the CDM group; 0 indicates that the DMRS port used for PDSCH in the CDM group is port 0, "0-1" indicates that the DMRS ports used for PDSCH in the CDM group are port 0 and port 1, "0-2" indicates that the DMRS ports used for PDSCH in the CDM group are port 0, port 1 and port 2, "0-3" indicates that the DMRS ports used for PDSCH in the CDM group are port 0, port 1, port 2 and port 3, and "2-3" indicates that the DMRS ports used for PDSCH in the CDM group are port 2 and port 3.

[0128] Based on the above methods, the terminal device can determine the multiple activated CDM groups based on DCI signaling, and determine the DMRS port used for PDSCH transmission in each activated CDM group. Each CDM group can be used for transmission by one transmission node, so it can support simultaneous transmission of multiple nodes and improve the throughput of downlink transmission.

[0129] In some implementations, the terminal device may also determine the TCI states corresponding to the K CDM groups based on DCI signaling. The network device sends DCI signaling to the terminal device, where the DCI signaling indicates the TCI states corresponding to the CDM groups; based on the DCI signaling states, the terminal device may determine the TCI states corresponding to the multiple CDM groups.

[0130] For example, the DCI signaling indicates M TCI states, the M TCI states correspond one-to-one to the M CDM groups used for PDSCH transmission in the K CDM groups, and M is a positive integer; or,

[0131] The DCI signaling indicates N TCI states, and the terminal device determines the TCI state corresponding to each CDM group used for PDSCH transmission in the K CDM groups from the N TCI states based on the correspondence between the TCI states and CDM groups indicated in advance by the network device through high-layer signaling; N is a positive integer; or

[0132] The DCI signaling indicates a first TCI state, a second TCI state, and a bitmap, where the bitmap is used to indicate that K TCI states respectively adopt the first TCI state or the second TCI state.

[0133] In one example, CDM groups corresponding to the same TCI state are associated with the same phase-tracking reference signal (PTRS) port.

[0134] According to the instructions of the DCI signaling, the terminal device can determine the TCI state corresponding to each CDM group in the K activated CDM groups to ensure the reception of each PDSCH.

[0135] The following specific embodiments are used to introduce how the terminal device determines the activated CDM group, how the terminal device determines the number of PDSCH transmission layers corresponding to different CDM groups in K CDM groups, how the terminal device determines the DMRS port used for PDSCH in each CDM group, and how the terminal device determines the TCI status corresponding to each CDM group.

[0136] Example 1:

[0137] In this embodiment, the terminal device determines K activated CDM groups, each CDM group including N DMRS ports. Specifically, the terminal device determines K activated CDM groups from L CDM groups agreed with the network device, where L is an integer greater than or equal to 3.

[0138] In one implementation, to support multiple nodes with two ports, six CDM groups can be supported in one OFDM symbol, each containing two DMRS ports, thus supporting 12 ports in one OFDM symbol. Assuming there are S DMRS symbols, there are a total of 12*S DMRS ports (i.e., L = 6*S CDM groups). An example is shown in Figures 5A and 5B , where resources with the same pattern represent the same CDM group, and resources with different patterns represent resources in different CDM groups.

[0139] In another implementation, to support multiple nodes with four ports, three CDM groups can be supported in one OFDM symbol, each containing four DMRS ports, thus supporting 12 ports in one OFDM symbol. Assuming there are S DMRS symbols, and the CDM groups in different symbols are TDM, there are a total of 12*S DMRS ports (i.e., L = 3*S CDM groups). An example is shown in Figures 5C and 5D, where the same pattern represents resources in the same CDM group, and the different patterns represent resources in different CDM groups.

[0140] In another implementation, K=L, that is, all CDM groups are activated CDM groups.

[0141] The number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured on the network device.

[0142] The value of K can be greater than 3, which means that more CDM groups can be supported than the existing system.

[0143] Example 2:

[0144] In this embodiment, the terminal device determines K activated CDM groups, each of which contains N DMRS ports. The terminal device may determine the K activated CDM groups from the L CDM groups agreed upon with the network device, where L is an integer greater than or equal to 3. Specifically, the terminal device receives high-layer signaling from the network device and determines the activated CDM groups based on the high-layer signaling. For example, the K activated CDM groups may be determined in one of the following ways:

[0145] Mode 1: The terminal device receives a bitmap indicated by higher-layer signaling. Each bit in the bitmap corresponds to a CDM group, and the CDM group corresponding to the bit with a value of 1 is the activated CDM group. For example, assuming L = 12, the bitmap has a length of 12, and 100001000000 indicates that the first and sixth CDM groups are activated.

[0146] Method 2: The terminal device receives the number of activated CDM groups K indicated by higher-layer signaling and determines CDM groups 1 to K as activated CDM groups. In other words, higher-layer signaling configures the value of K and then determines the first K CDM groups among L CDM groups as activated CDM groups.

[0147] Method 3: The terminal device receives the number of DMRS symbols S indicated by higher-layer signaling and determines that the CDM groups on the S DMRS symbols are active CDM groups. In other words, if the higher-layer signaling configures the number of DMRS symbols S, then the CDM groups on these S DMRS symbols are all active CDM groups. The positions of the S DMRS symbols are pre-agreed between the terminal device and the network device.

[0148] Method 4: The terminal device receives Radio Resource Control (RRC) signaling and a Media Access Control Element (MAC CE) from the network device. The RRC signaling indicates the number of DMRS symbols (S), and the MAC CE indicates the CDM group activated on the S DMRS symbols. In other words, RRC signaling configures the number of DMRS symbols (S), while the MAC CE indicates the activated CDM group from the S OFDM CDM groups. The two signaling steps combine to activate the CDM group.

[0149] The number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured on the network device.

[0150] The value of K can be greater than 3, which means that more CDM groups can be supported than the existing system.

[0151] Example 3:

[0152] In this embodiment, the terminal device determines K activated CDM groups, each CDM group containing N DMRS ports. Specifically, the terminal device may determine the K activated CDM groups from the L CDM groups agreed upon with the network device, where L is an integer greater than or equal to 3. Specifically, the terminal device receives DCI signaling from the network device and determines the activated CDM groups based on the DCI signaling. Specifically, one of the following methods may be included:

[0153] Method 1: DCI signaling indicates a bitmap, where each bit in the bitmap corresponds to a CDM group, and the CDM group corresponding to the bit with a value of 1 is the activated CDM group. For example, assuming the bitmap is 6 in length, 101001 indicates activation of the 1st, 3rd, and 6th CDM groups.

[0154] Method 2: DCI signaling indicates the number of activated CDM groups, K, and the first to Kth CDM groups of the agreed L CDM groups are activated. In other words, DCI signaling configures the value of K and then determines the first K CDM groups of the L CDM groups as the activated CDM groups.

[0155] Method 3: DCI signaling indicates the number of DMRS symbols S, and the CDM groups corresponding to the S DMRS symbols are activated CDM groups. In other words, if DCI signaling configures the number of DMRS symbols S, then the CDM groups corresponding to the S DMRS symbols are all activated CDM groups.

[0156] Method 4: Determine that the number of activated CDM groups is equal to the number of TCI states indicated in the DCI signaling. That is, the network device does not need to specifically indicate the number of activated CDM groups, and the terminal device can determine the number of indicated TCI states as the number of activated CDM groups based on the TCI state indication information in the DCI signaling. After determining the number K of activated CDM groups, the terminal device can determine the first K CDM groups among the L CDM groups as activated CDM groups.

[0157] The number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured on the network device.

[0158] The value of K can be greater than 3, which means that more CDM groups can be supported than the existing system.

[0159] Example 4:

[0160] In this embodiment, the terminal device determines K activated CDM groups, each CDM group containing N DMRS ports. Specifically, the terminal device can determine the K activated CDM groups from the L CDM groups agreed with the network device, where L is an integer greater than or equal to 3. Specifically, the terminal device can determine that the number of activated CDM groups is equal to the maximum number of transmission layers configured by the network device. The maximum number of transmission layers configured by the network device can be indicated by RRC signaling. For example, after determining the number K of activated CDM groups, the terminal device can determine that the first K CDM groups among the L CDM groups are activated CDM groups.

[0161] The number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured on the network device.

[0162] The value of K can be greater than 3, which means that more CDM groups can be supported than the existing system.

[0163] Embodiment 5:

[0164] In this embodiment, the terminal device determines the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups, and / or the DMRS ports used for PDSCH in each CDM group.

[0165] Specifically, the terminal device receives the DCI signaling sent by the network device, and determines the number of physical downlink shared channel (PDSCH) transmission layers corresponding to each CDM group in the activated CDM group, or the DMRS port for PDSCH in each CDM group according to the DCI signaling.

[0166] Correspondingly, the network device sends DCI signaling, which is used to determine the PDSCH transmission layer corresponding to each of the activated K CDM groups, or the DMRS ports for PDSCH within each CDM group.

[0167] In some embodiments, the terminal device may only determine the transmission layers corresponding to the k CDM groups actually used for PDSCH DMRS transmission among the activated CDM groups, or the DMRS ports for PDSCH within these k CDM groups; the transmission layers corresponding to the other CDM groups are defaulted to 0 (if k < K), that is, the DMRS ports of the other CDM groups are not used for the terminal's PDSCH. That is to say, the transmission layers of some of the K CDM groups can be 0, that is, not used for PDSCH transmission, and the DMRS ports therein are also not used for the terminal's PDSCH.

[0168] In one embodiment, the terminal device still needs to perform rate matching on the physical resources occupied by the K - k CDM groups not used for DMRS transmission, because these CDM groups may be used for DMRS transmission of other multiplexed users.

[0169] In one embodiment, the DCI signaling includes a first information field, which respectively indicates the PDSCH transmission layer corresponding to each of the activated K CDM groups. The following gives two specific examples for a CDM group containing different numbers of DMRS ports:

[0170] (1) Example 1:

[0171] If a CDM group contains two DMRS ports, the value range of the PDSCH transmission layer corresponding to each CDM group can be {1, 2}, {0, 1, 2} or {0, 1, 2, NULL}; the PDSCH transmission layer corresponding to each CDM group can be any value in the value range. Among them,

[0172] 0 indicates that the CDM group is not used to send the terminal's DMRS, that is, the PDSCH transmission layer corresponding to this CDM group is 0; however, the terminal device needs to perform rate matching on the resources occupied by this CDM group;

[0173] 1 indicates that the CDM group is used to transmit 1 transmission layer, that is, the PDSCH transmission layer corresponding to this CDM group is 1;

[0174] 2 indicates that the CDM group is used to transmit 2 transmission layers, that is, the PDSCH transmission layer corresponding to this CDM group is 2;

[0175] Null indicates that the CDM group is not used to transmit the terminal's DMRS, that is, the number of PDSCH transmission layers corresponding to the CDM group is 0; and the terminal device does not need to perform rate matching on the resources occupied by the CDM group. Alternatively, other symbols can be used to represent the above situation. For example, 3 is used to indicate that the CDM group is not used to transmit the terminal's DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0176] The above representation is only an example, and this application does not limit the specific representation of different values ​​of the number of PDSCH transmission layers corresponding to the CDM group. Among them, 0 and Null can also be described in other ways. For example, the physical meanings expressed by 0 and Null are interchangeable, that is, Null indicates that the CDM group is not used to send the DMRS of the terminal, but the terminal device needs to perform rate matching on the resources occupied by the CDM group; 0 indicates that the CDM group is not used to send the DMRS of the terminal, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0177] For different value ranges of the number of PDSCH transmission layers corresponding to the CDM group, signaling of different lengths may be used to indicate the number of transmission layers.

[0178] For example, if the value range of the number of transmission layers is {1,2}, each CDM group can indicate the number of transmission layers through 1 bit of signaling, and a total of K bits of signaling are required to indicate the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups; if the value range of the number of transmission layers is {0,1,2}, each CDM group needs to indicate the number of transmission layers through 2 bits of signaling, and a total of 2K bits of signaling are required to indicate the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups; if the value range of the number of transmission layers is {0,1,2,NULL}, each CDM group needs to indicate the number of transmission layers through 2 bits of signaling, and a total of 2K bits of signaling are required to indicate the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups.

[0179] (2) Example 2:

[0180] If a CDM group contains 4 DMRS ports, the value range of the number of transmission layers corresponding to each CDM group can be {1,2,3,4}, {0,1,2,3,4} or {0,1,2,3,NULL}; the number of PDSCH transmission layers corresponding to each CDM group can be any value in the value range.

[0181] 0 means that the CDM group is not used to send the terminal's DMRS, that is, the number of PDSCH transmission layers corresponding to the CDM group is 0; but the terminal device needs to perform rate matching on the resources occupied by the CDM group;

[0182] 1 means that the CDM group is used to transmit 1 transmission layer, that is, the number of PDSCH transmission layers corresponding to the CDM group is 1;

[0183] 2 means that the CDM group is used to transmit 2 transmission layers, that is, the number of PDSCH transmission layers corresponding to this CDM group is 2;

[0184] 3 means that the CDM group is used to transmit 3 transmission layers, that is, the number of PDSCH transmission layers corresponding to this CDM group is 3;

[0185] 4 means that the CDM group is used to transmit 4 transmission layers, that is, the number of PDSCH transmission layers corresponding to this CDM group is 4;

[0186] Null indicates that the CDM group is not used to transmit the terminal's DMRS, that is, the number of PDSCH transmission layers corresponding to the CDM group is 0; and the terminal device does not need to perform rate matching on the resources occupied by the CDM group. Alternatively, other symbols can be used to represent the above situation. For example, 5 is used to indicate that the CDM group is not used to transmit the terminal's DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0187] The above representation is only an example, and this application does not limit the specific representation of different values ​​of the number of PDSCH transmission layers corresponding to the CDM group. Among them, 0 and Null can also be described in other ways. For example, the physical meanings expressed by 0 and Null are interchangeable, that is, Null indicates that the CDM group is not used to send the DMRS of the terminal, but the terminal device needs to perform rate matching on the resources occupied by the CDM group; 0 indicates that the CDM group is not used to send the DMRS of the terminal, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0188] For different value ranges of the number of PDSCH transmission layers corresponding to the CDM group, signaling of different lengths may be used to indicate the number of transmission layers.

[0189] For example, if the value range of the number of transmission layers is {1,2,3,4}, each CDM group can indicate the number of transmission layers through 2 bits of signaling, and a total of 2K bits of signaling are required to indicate the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups; if the value range of the number of transmission layers is {0,1,2,3,4}, each CDM group can indicate the number of transmission layers through 3 bits of signaling, and a total of 3K bits of signaling are required to indicate the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups; if the value range of the number of transmission layers is {0,1,2,3,NULL}, each CDM group can indicate the number of transmission layers through 3 bits of signaling, and a total of 3K bits of signaling are required to indicate the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups.

[0190] In one embodiment, if the number of transmission layers is n, the first n DMRS ports of the corresponding CDM group can be used for DMRS transmission of the terminal. In another embodiment, the network device can additionally indicate 1 bit or 2 bits of information through high-layer signaling or physical layer signaling, and the information is used to indicate which DMRS ports in the CDM group are used to transmit DMRS. For example, in the case where a CDM group contains 2 ports, 1 bit can be used to indicate whether the first or second DMRS port is used to transmit DMRS; in the case where a CDM group contains 4 DMRS ports, 2 bits can be used to indicate that one of the four DMRS ports is used for DMRS transmission (corresponding to a PDSCH transmission layer number of 1), or 1 bit can be used to indicate whether the first two or the last two DMRS ports are used for DMRS transmission (corresponding to a PDSCH transmission layer number of 2).

[0191] In one embodiment, the DCI signaling includes an information field that indicates the DMRS ports used for PDSCH in each of the K activated CDM groups. The following are two specific examples of a CDM group containing different numbers of DMRS ports:

[0192] (1) Example 1:

[0193] If a CDM group contains two DMRS ports, the value range of the DMRS port used for PDSCH in each CDM group can be {0, 1, 0-1} or {0, 1, 0-1, Null}; the DMRS port used for PDSCH in each CDM group can be any value in the value range.

[0194] 0 means that the DMRS port used for PDSCH in the CDM group is port 0;

[0195] 1 indicates that the DMRS port used for PDSCH in the CDM group is port 1;

[0196] 0-1 indicates that the DMRS ports used for PDSCH in the CDM group are port 0 and port 1;

[0197] Invalid (Null) indicates that the CDM group is not used to send the DMRS of the terminal.

[0198] The above representation is only an example, and this application does not limit the specific representation of different values ​​of the number of PDSCH transmission layers corresponding to the CDM group. Among them, 0 and Null can also use other description methods to indicate the same meaning. For example, the physical meanings expressed by 0 and Null can also be interchangeable. That is, Null indicates that the DMRS port used for PDSCH in the CDM group is port 0, and 0 indicates that the CDM group is not used to send DMRS to the terminal.

[0199] For different value ranges of DMRS ports used for PDSCH in a CDM group, signaling of different lengths may be used to indicate the number of transmission layers.

[0200] For example, if the value range of the DMRS port is {0, 1, 0-1}, each CDM group needs to indicate the DMRS port through 2 bits of signaling, and a total of 2K bits are required to indicate the DMRS port used for PDSCH in each CDM group in the K CDM groups; if the value range of the DMRS port is {0, 1, 0-1, Null}, each CDM group needs to indicate the DMRS port through 2 bits of signaling, and a total of 2K bits are required to indicate the DMRS port used for PDSCH in each CDM group in the K CDM groups.

[0201] (2) Example 2:

[0202] If a CDM group contains two DMRS ports, the value range of the DMRS port used for PDSCH in each CDM group can be {0,1,2,3,0-1,2-3,0-2,0-3} or {0,1,2,3,0-1,2-3,0-2,0-3,Null}; the DMRS port used for PDSCH in each CDM group can be any value in the value range.

[0203] 0 means that the DMRS port used for PDSCH in the CDM group is port 0;

[0204] 1 indicates that the DMRS port used for PDSCH in the CDM group is port 1;

[0205] 0-1 means that the DMRS ports used for PDSCH in the CDM group are port 0 and port 1; and so on;

[0206] Invalid (Null) indicates that the CDM group is not used to send the DMRS of the terminal.

[0207] Here, 0 and Null can also use other description methods to indicate the same meaning. For example, the physical meanings expressed by the two can be interchanged. For example, invalid (Null) means that the DMRS port for PDSCH in the CDM group is port 0, and 0 means that the CDM group is not used to send the DMRS of the terminal. The above representation is only an example, and this application does not limit the specific representation methods of different values of the DMRS port for PDSCH in the CDM group.

[0208] For different value ranges of the DMRS port for PDSCH in the CDM group, signaling of different lengths can be used to indicate the number of transmission layers.

[0209] For example, if the value range of the DMRS port is {0, 1, 2, 3, 0-1, 2-3, 0-2, 0-3}, then each CDM group needs 3-bit signaling to indicate the DMRS port, and a total of 3K bits are required to indicate the DMRS port for PDSCH in each of the K CDM groups.

[0210] In the embodiments of this application, the number of transmission layers of PDSCH is the sum of the number of DMRS ports included in all CDM groups.

[0211] Embodiment Six:

[0212] In this embodiment, the terminal device determines the PDSCH transmission layer corresponding to each different CDM group among the K CDM groups.

[0213] Specifically, the terminal device receives the DCI signaling sent by the network device, and determines the PDSCH transmission layer corresponding to each CDM group among the K CDM groups according to the DCI signaling.

[0214] Correspondingly, the network device sends DCI signaling, and the DCI signaling is used to determine the PDSCH transmission layer corresponding to each CDM group among the K CDM groups.

[0215] In this embodiment, the terminal device can only determine the transmission layers corresponding to the k CDM groups actually used for PDSCH DMRS transmission among the K CDM groups, and the transmission layers corresponding to the other CDM groups are defaulted to 0 (if k < K), that is, not used for PDSCH DMRS transmission, so no special determination step is required.

[0216] In one implementation, the terminal device still needs to perform rate matching on the physical resources occupied by the K-k CDM groups not used for DMRS transmission, because these CDM groups may be used for DMRS transmission of other multiplexed users.

[0217] In one embodiment, the DCI signaling indicates the number of PDSCH transmission layers and the allocation method of the PDSCH transmission layers in K CDM groups; the terminal device can determine the number of PDSCH transmission layers corresponding to each CDM group based on the allocation method.

[0218] In one example, the allocation of transport layers in K CDM groups is a combination of k transport layer numbers, where the k transport layer numbers correspond to the first k CDM groups in the K CDM groups, or to the k CDM groups indicated by the network device in the K CDM groups, where k is less than or equal to K. In this case, the number of transport layers corresponding to the other Kk CDM groups is 0 (if k <K)。

[0219] For example, when k=1, if the combination of k transmission layer numbers is {2}, it means that only one CDM group is actually used for DMRS transmission, and the number of transmission layers corresponding to this CDM group is 2; if K>1, the number of transmission layers corresponding to other CDM groups is 0.

[0220] For example, when k = 3, if the combination of k transmission layer numbers is {1, 1, 2}, it means that three CDM groups are actually used for DMRS transmission, and the corresponding transmission layer numbers are 1, 1, and 2 respectively; if K>3, the transmission layer number corresponding to the other CDM groups is 0.

[0221] The network device may indicate k CDM groups through DCI signaling or higher-layer signaling, for example, through a K-bit bitmap. The bitmap is K bits long, with each bit corresponding to one of the K activated CDM groups. When a bit value is 1, it indicates that the corresponding CDM group is actually used for PDSCH DMRS transmission; when a bit value is 0, it indicates that the corresponding CDM group is not used for PDSCH DMRS transmission. In this bitmap, k bits have a value of 1, and the remaining bits have a value of 0.

[0222] In one embodiment, the difference between the maximum and minimum values ​​of the k transmission layer numbers does not exceed 0, where 0 = 1 or 2. That is, among the K CDM groups corresponding to the CDM groups actually used for PDSCH DMRS transmission, the difference between the maximum and minimum transmission layer numbers does not exceed 0. This restriction ensures the performance of multi-node transmission. If the number of transmission layers differs significantly between multiple nodes, it indicates that the channel gains between the multiple nodes vary significantly, making multipoint transmission unsuitable. This embodiment, by limiting the maximum difference in the number of transmission layers corresponding to different CDM groups, ensures that the channel gains between multiple nodes do not vary significantly, making multipoint transmission suitable.

[0223] In one embodiment, if the number of transmission layers corresponding to a CDM group is n, the first n DMRS ports of the corresponding CDM group are used for DMRS transmission of the terminal. In another embodiment, the network device may additionally indicate 1-2 bits of information through high-layer signaling or physical layer signaling, which is used to indicate which ports in the CDM group are used for DMRS transmission. For example, if a CDM group contains two ports, one bit may be used to indicate whether the first or second port is used for DMRS transmission.

[0224] In the following description, it is assumed that the difference between the maximum number of transmission layers and the minimum number of transmission layers does not exceed 1. If there is no such restriction, the corresponding table can be directly extended to support more combinations of transmission layer numbers.

[0225] In some implementations, the network device indicates an index through DCI signaling, where the index corresponds to a rank and a combination of transmission layers, where the rank is equal to the total number of transmission layers; the terminal can determine the number of transmission layers corresponding to the currently used CDM group based on this index.

[0226] The case where each CDM group contains two DMRS ports is shown in Table 1 or Table 2. Table 1 does not include layer flipping, while Table 2 does. The transmission layer numbers within a transmission layer combination in Table 1 can be interchanged without affecting the effect. For example, {1,2} and {2,1} are equivalent, and {1,1,2,2}, {1,2,1,2}, {1,2,2,1}, {2,1,2,1}, {2,1,1,2}, and {2,2,1,1} are also equivalent.

[0227] For example, in Table 1, when Index = 3, it indicates Rank = 3 (indicating a total of 3 transmission layers), and two CDM groups are used, where the first CDM group corresponds to 2 transmission layers and the second CDM group corresponds to 1 transmission layer (represented by {2,1} in Table 1). Since swapping the transmission layers within a transmission layer combination does not affect the effect, for example, in two CDM groups, the first CDM group corresponds to 1 transmission layer and the second CDM group corresponds to 2 transmission layers (such as can be represented by {1,2}) is equivalent to {2,1}, so Table 1 does not indicate the case of {1,2}. It can be seen that Table 1 does not include flipping between layers. In some examples, Rank = 3 is also used to indicate the case of {1,2}, but not {2,1}.

[0228] For example, in Table 2, when Index = 3, it indicates Rank = 3 (indicating a total number of transmission layers of 3), and two CDM groups are used, where the first CDM group corresponds to 2 transmission layers, and the second CDM group corresponds to 1 transmission layer (indicated by {2,1} in Table 1). In Table 2, when Index = 5, Rank = 3 (indicating a total number of transmission layers of 3), it indicates the use of two CDM groups, where the first CDM group corresponds to 1 transmission layer, and the second CDM group corresponds to 2 transmission layers (indicated by {1,2} in Table 2). As can be seen, Table 2 includes flipping between layers. When using Table 2, the interchange between transmission layer numbers corresponds to different allocation methods, and therefore needs to be indicated by different indices. For example, {1,2} and {2,1} are not equivalent.

[0229] In addition, in one implementation of Table 1 and Table 2, the Rank column is optional. The terminal device can sum the number of transmission layers corresponding to each CDM group to obtain the total Rank value, so there is no need to reflect the Rank in the table.

[0230] In another embodiment, the column for the number of CDM groups (i.e., K) is optional. The terminal device can derive the value of K based on the number of transmission layers indicated, so it does not need to be reflected in the table. For example, the transmission layer combination {1,2} corresponds to K = 2, and the transmission layer combination {1,2,2} corresponds to K = 3.

[0231] In Tables 1 and 2, there is a correlation between Rank (Rank equals the total number of transmission layers), the number of CDM groups used, and the transmission layer combination. For example, the sum of the transmission layer numbers corresponding to all CDM groups equals Rank. Furthermore, Tables 1 and 2 are based on the case where each CDM group contains two DMRS ports. Therefore, the value of each transmission layer number in the transmission layer combination can be 1 or 2.

[0232] In actual use, only a portion of Table 1 or a portion of Table 2 may be used.

[0233] For example, if the network device configures the terminal device to use only some of the Rank values ​​(for example, a Rank Indication Restriction (RI restriction) is configured), the table may only contain the content in the rows corresponding to the Rank values ​​configured by the network device; or, the terminal device only uses the rows corresponding to the Rank values ​​configured by the network device in the table, and does not use other rows. In one example, if the network device configures the terminal device to use only Rank = 1, 2, and 4, then in actual use, only the rows corresponding to Rank = 1, 2, and 4 are used.

[0234] For example, if the network device limits the maximum number of transmission layers (referred to as the maximum number of transmission layers), the table can only include the content in the rows whose Rank is less than or equal to the maximum number of transmission layers; or, the terminal device only uses the rows in the table whose Rank is less than or equal to the maximum number of transmission layers, and does not use other rows. In one example, if the network device is configured with a maximum number of transmission layers of 4, in actual use, only the rows corresponding to Rank less than or equal to 4 are used, that is, the rows corresponding to Rank = 1, 2, 3, and 4.

[0235] It is easy to understand that when only part of the content in the table is used, the length of the bit used to indicate the index value can be shortened. In subsequent tables, only part of the table can be used in actual use, and this application will not go into details.

[0236] In addition, in Table 1, as the index value increases, they are arranged in order from small to large according to Rank; for the same Rank, they are arranged in order from small to large according to the number of CDM groups. In other embodiments, as the index value increases, they can be arranged in order from small to large according to the number of CDM groups; for the same number of CDM groups, they can be arranged in order from small to large according to Rank. For example, index = 0 and 1 represent the case where the number of CDM groups = 1 (wherein, index = 0 represents the case where the number of CDM groups = 1 and Rank = 1, and index = 1 represents the case where the number of CDM groups = 1 and Rank = 2); index = 2, 3 and 4 represent the case where the number of CDM groups = 2, and so on. For the case where the table does not directly indicate the Rank or the number of CDM groups, the above method can still be used to arrange the number of transmission layer combinations, where the Rank value can be obtained by summing the number of transmission layers corresponding to each CDM group, and the value of K (i.e., the number of CDM groups used) can be obtained by the number of indicated transmission layers. That is to say, the combinations of transmission layer numbers indicated by the index can be arranged in ascending order according to the results of summing the numbers of transmission layers corresponding to each CDM group (if the results are the same, they can be arranged in ascending order according to the number of indicated transmission layers), or arranged in ascending order according to the number of indicated transmission layers (if the numbers are the same, they can be arranged in ascending order according to the results of summing the numbers of transmission layers corresponding to each CDM group).

[0237] In Table 2, they are arranged in ascending order of Rank.

[0238] The physical meanings of the different index values ​​in Tables 1 and 2 are examples only and are not limited in this embodiment. Tables 1 and 2 only apply to the case where the maximum number of transmission layers is 8. For cases where the maximum number of transmission layers is greater than 8, a direct expansion can be performed based on the following table.

[0239] Table 1

[0240] Table 2

[0241] The case where each CDM group contains four DMRS ports is shown in Table 3 or Table 4. Table 3 does not include layer flipping, while Table 4 does. The transmission layer numbers within a transmission layer combination in Table 3 can be interchanged without affecting the performance. For example, {3,2} and {2,3} are equivalent, and {3,2,2}, {2,3,2}, and {2,2,3} are also equivalent.

[0242] For example, in Table 3, when Index = 4, it indicates Rank = 3 (indicating that the total number of transmission layers is 3), and two CDM groups are used, where the number of transmission layers corresponding to the first CDM group is 2 and the number of transmission layers corresponding to the second CDM group is 1 (indicated by {2,1} in Table 3). Since the transmission layer numbers within a transmission layer combination are interchanged without affecting the effect, for example, the number of transmission layers corresponding to the first CDM group in the two CDM groups is 1 and the number of transmission layers corresponding to the second CDM group is 2 (as can be represented by {1,2}), which is equivalent to {2,1}, Table 3 does not indicate the case of {1,2}. It can be seen that Table 3 does not include flipping between layers. In some examples, Rank = 3 is also used to indicate the case of {1,2}, but not {2,1}.

[0243] For example, in Table 4, when Index = 4, it indicates Rank = 3 (indicating a total of 3 transmission layers), and two CDM groups are used, where the first CDM group corresponds to 2 transmission layers, and the second CDM group corresponds to 1 transmission layer. In Table 4, when Index = 6, it indicates Rank = 3 (indicating a total of 3 transmission layers), and two CDM groups are used, where the first CDM group corresponds to 1 transmission layer, and the second CDM group corresponds to 2 transmission layers. As can be seen, Table 4 includes flipping between layers. When using Table 4, the interchange of transmission layer numbers corresponds to different allocation methods, and therefore needs to be indicated by different indices. For example, {1,2} and {2,1} are not equivalent.

[0244] In addition, in one implementation of Table 3 and Table 4, the Rank column is optional. The terminal device can sum the number of transmission layers corresponding to each CDM group to obtain the total Rank value, so there is no need to reflect the Rank in the table.

[0245] In another embodiment, the column for the number of CDM groups (i.e., K) is optional. The terminal device can obtain the value of K based on the number of transmission layers indicated, so it does not need to be reflected in the table. For example, the transmission layer combination {2,1} corresponds to K = 2, and the transmission layer combination {2,1,1} corresponds to K = 3.

[0246] In Tables 3 and 4, there is a correlation between Rank (Rank equals the total number of transmission layers), the number of CDM groups used, and the transmission layer combination. For example, the sum of the transmission layer numbers corresponding to all CDM groups equals Rank. Furthermore, Tables 3 and 4 are based on the case where each CDM group contains four DMRS ports. Therefore, the values ​​of the transmission layer numbers in each transmission layer combination can be 1, 2, 3, or 4.

[0247] In addition, in Table 3, as the index value increases, it is arranged in order of Rank from small to large; for the same Rank, it is arranged in order of the number of CDM groups from small to large. In other embodiments, it can be arranged in order of the number of CDM groups from small to large; for the same number of CDM groups, it can be arranged in order of Rank from small to large. For example, index = 0, 1, 2 and 3, represents the case where the number of CDM groups = 1 (wherein, index = 0 represents the case where the number of CDM groups = 1 and Rank = 1, index = 1 represents the case where the number of CDM groups = 1 and Rank = 2; index = 3 represents the case where the number of CDM groups = 1 and Rank = 3, index = 4 represents the case where the number of CDM groups = 1 and Rank = 4); index = 4, 5, 6, 7, 8 and 9 represent the case where the number of CDM groups = 2, and so on. For the case where the table does not directly indicate the Rank or the number of CDM groups, the above method can still be used to arrange the combinations of transmission layer numbers, wherein the Rank value can be obtained by summing the numbers of transmission layers corresponding to each CDM group, and the value of K (i.e., the number of CDM groups used) can be obtained by the number of indicated transmission layers. In other words, the combinations of transmission layer numbers indicated by the index can be arranged in ascending order according to the result of summing the numbers of transmission layers corresponding to each CDM group (if the results are the same, they are arranged in ascending order according to the number of indicated transmission layers), or in ascending order according to the number of indicated transmission layers (if the numbers are the same, they are arranged in ascending order according to the result of summing the numbers of transmission layers corresponding to each CDM group).

[0248] In Table 4, they are arranged in ascending order of Rank.

[0249] In Tables 3 and 4, the meanings of the different index values ​​are for illustrative purposes only and are not limited in the present application. Tables 3 and 4 only cover the case where the maximum number of transmission layers is 8. For cases where the maximum number of transmission layers is greater than 8, a direct expansion can be performed based on the following table.

[0250] In addition, in actual use, only a portion of Table 3 or a portion of Table 4 may be used. The specific method can refer to the above introduction to Table 1 and Table 2, which will not be repeated here.

[0251] Table 3

[0252] Table 4

[0253] In addition, the number of DMRS ports included in each CDM group can be configured by the network device. For example, the network device uses RRC signaling to configure the number of DMRS ports included in each CDM group, and the network device can be configured according to the capabilities of the terminal device and / or the capabilities of the sub-nodes. For example, if the network device pre-configures each CDM group to include 2 DMRS ports, the terminal device can determine the number of transmission layers corresponding to each CDM group according to Table 1 or Table 2 above; if the network device pre-configures each CDM group to include 4 DMRS ports, the terminal device can determine the number of transmission layers corresponding to each CDM group according to Table 3 or Table 4 above.

[0254] The network device sends the PDSCH and the DMRS on the corresponding DMRS port, which comes from the K activated CDM groups. The terminal device determines the corresponding DMRS port for each CDM group based on the number of transmission layers corresponding to each CDM group in the activated CDM groups, and then demodulates the PDSCH.

[0255] Embodiment seven:

[0256] In this embodiment, the terminal device determines the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups.

[0257] Specifically, the terminal device receives the DCI signaling sent by the network device, and determines the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups according to the DCI signaling.

[0258] Accordingly, the network device sends DCI signaling, where the DCI signaling is used to determine the number of PDSCH transmission layers corresponding to each of the K CDM groups.

[0259] In one embodiment, since the DCI signaling indicates the number of activated CDM groups, the DCI signaling can directly indicate the number of transmission layers corresponding to the activated CDM group. That is, for different values ​​of K, the number of transmission layers and the distribution method of the transmission layers in the K CDM groups can be indicated based on different tables through the same DCI signaling. Based on this method, the DCI signaling only needs to indicate the number of transmission layers from the combination of the number of transmission layers corresponding to one value of K, and does not need to indicate the number of transmission layers from the combination of the number of transmission layers corresponding to all values ​​of K (i.e., the method described in Example 7), thereby effectively reducing the overhead of the DCI signaling.

[0260] In one example, the allocation of transmission layers among the K CDM groups is a combination of K transmission layer numbers, and the K transmission layer numbers correspond one-to-one to the K activated CDM groups.

[0261] In one embodiment, the difference between the maximum and minimum values ​​of the K transmission layer numbers does not exceed 0, where 0=1 or 2. That is, the difference between the maximum and minimum transmission layer numbers of the K CDM groups corresponding to the CDM groups actually used for PDSCH DMRS transmission does not exceed 0.

[0262] In one embodiment, if the number of transmission layers corresponding to a CDM group is n, the first n DMRS ports of the corresponding CDM group are used for DMRS transmission of the terminal device. In another embodiment, the network device may additionally indicate 1-2 bits of information through high-layer signaling or physical layer signaling, which is used to indicate which ports in the CDM group are used for DMRS transmission.

[0263] In the following description, it is assumed that the difference between the maximum number of transmission layers and the minimum number of transmission layers does not exceed 1. If there is no such restriction, the corresponding table can be directly extended to support more combinations of transmission layer numbers.

[0264] Examples of each CDM group containing two DMRS ports are shown in Tables 5 to 11 or Tables 12 to 18. Tables 5 to 11 do not include flipping between layers (similar to the situations in Tables 1 and 3 above, refer to the descriptions of Tables 1 and 3); Tables 12 to 18 include flipping between layers (similar to the situations in Tables 2 and 4 above, refer to the descriptions of Tables 2 and 4). Among them, the transmission layer numbers within a transmission layer number combination in Tables 5 to 11 can be interchanged without affecting the effect. For example, {1,2} and {2,1} are equivalent, and {1,1,2,2}, {1,2,1,2}, {1,2,2,1}, {2,1,2,1}, {2,1,1,2}, and {2,2,1,1} are equivalent.

[0265] In Tables 5-18, there is a correlation between Rank (Rank equals the total number of transmission layers) and the number of transmission layers combined. For example, the sum of the number of transmission layers corresponding to all CDM groups equals Rank. Furthermore, Tables 5-18 are based on the case where each CDM group contains two DMRS ports. Therefore, the value of each transmission layer number in the transmission layer combination can be 1 or 2.

[0266] In addition, in one implementation of Tables 5-18, the Rank column is optional. The terminal device can sum the number of transmission layers corresponding to each CDM group to obtain the total Rank value, so there is no need to reflect the Rank in the table.

[0267] In Tables 5-18, as the index value increases, the transmission layer combinations are arranged in ascending order based on Rank (Rank is equal to the total number of transmission layers). For tables that do not directly indicate Rank, the transmission layer combinations indicated by the index can be arranged in ascending order based on the sum of the transmission layer numbers corresponding to each CDM group.

[0268] The network device indicates an index through DCI signaling. The index corresponds to a Rank value and a combination of transmission layers, where Rank is equal to the total number of transmission layers. Based on this index, the terminal can determine the number of transmission layers corresponding to the K CDM groups from the table corresponding to the current K. In other words, different K values ​​correspond to different tables. The terminal device determines which table to use to obtain the combination of transmission layers based on the K value indicated by the DCI signaling. The terminal device then determines the specific combination of transmission layers from the table corresponding to the K value through the index indicated by the DCI signaling. The length of the index can be determined according to the number of transmission layer combinations it indicates. For example, if three transmission layer combinations are indicated in Table 6, the length of the index can be set to 3 bits. The three values ​​of the index are used to indicate the three transmission layer combinations, and the remaining five values ​​are reserved values.

[0269] Tables 5-11 are used to determine the transmission layer combinations for K activated CDM groups when K = 1, 2, 3, 4, 5, 6, and 7, respectively. Tables 12-18 are used to determine the transmission layer combinations for K activated CDM groups when K = 1, 2, 3, 4, 5, 6, and 7, respectively. When K = 8, the transmission layer combination does not need to be indicated through DCI signaling, and the only transmission layer combination is {1, 1, 1, 1, 1, 1, 1}.

[0270] For example, when each CDM group contains 2 DMRS ports, when K=2, the terminal device determines to use Table 6 or Table 13 to obtain the transmission layer combination based on the K value; and then determines the transmission layer combination from Table 6 or Table 13 through the index indicated by the DCI signaling.

[0271] It should be noted that this embodiment is only for the case where the maximum number of transmission layers is 8. For the case where the number of transmission layers is greater than 8, direct expansion can be performed based on the following table.

[0272] Table 5 Number of activated CDM groups K=1

[0273] Table 6 Number of activated CDM groups K=2

[0274] Table 7 Number of activated CDM groups K=3

[0275] Table 8 Number of activated CDM groups K=4

[0276] Table 9 Number of activated CDM groups K=5

[0277] Table 10 Number of activated CDM groups K=6

[0278] Table 11 Number of activated CDM groups K=7

[0279] Table 12 Number of activated CDM groups K=1

[0280] Table 13 Number of activated CDM groups K=2

[0281] Table 14 Number of activated CDM groups K=3

[0282] Table 15 Number of activated CDM groups K=4

[0283] Table 16 Number of activated CDM groups K=5

[0284] Table 17 Number of activated CDM groups K=6

[0285] Table 18 Number of activated CDM groups K=7

[0286] Examples of each CDM group containing 4 DMRS ports are shown in Tables 19 to 25 or Tables 26 to 32. Tables 19 to 25 do not include flipping between layers (similar to the above cases in Tables 1 and 3, refer to the descriptions of Tables 1 and 3); Tables 26 to 32 include flipping between layers (similar to the above cases in Tables 2 and 4, refer to the descriptions of Tables 2 and 4). Among them, the transmission layer numbers within a transmission layer number combination in Tables 19 to 25 can be interchanged without affecting the effect. For example, {3,2} and {2,3} are equivalent, and {2,2,3,3} and {2,3,3,2} are equivalent.

[0287] In Tables 19-32, there is a correlation between Rank (Rank equals the total number of transmission layers) and the number of transmission layers combined. For example, the sum of the number of transmission layers corresponding to all CDM groups equals Rank. Furthermore, Tables 19-32 are based on the case where each CDM group contains four DMRS ports. Therefore, the number of transmission layers in each transmission layer combination can be 1, 2, 3, or 4.

[0288] In addition, in one implementation of Tables 19-32, the Rank column is optional. The terminal device can sum the number of transmission layers corresponding to each CDM group to obtain the total Rank value, so there is no need to reflect the Rank in the table.

[0289] In Tables 19-32, as the index value increases, the transmission layer combinations are arranged in ascending order based on Rank (Rank is equal to the total number of transmission layers). For tables that do not directly indicate Rank, the transmission layer combinations indicated by the index can be arranged in ascending order based on the sum of the transmission layer numbers corresponding to each CDM group.

[0290] Tables 19-25 are used to determine the transmission layer combinations for K activated CDM groups when K = 1, 2, 3, 4, 5, 6, and 7, respectively. Tables 26-32 are used to determine the transmission layer combinations for K activated CDM groups when K = 1, 2, 3, 4, 5, 6, and 7, respectively. When K = 8, the transmission layer combination does not need to be indicated through DCI signaling, and the only transmission layer combination is {1, 1, 1, 1, 1, 1, 1}.

[0291] For example, when each CDM group contains 4 DMRS ports, when K is 3, the terminal device determines to use Table 21 or Table 28 to obtain the transmission layer combination based on the K value; and then determines the transmission layer combination from Table 21 or Table 28 through the index indicated by the DCI signaling.

[0292] It should be noted that this embodiment is only for the case where the maximum number of transmission layers is 8. For the case where the number of transmission layers is greater than 8, direct expansion can be performed based on the following table.

[0293] Table 19 Number of activated CDM groups K=1

[0294] Table 20 Number of activated CDM groups K=2

[0295] Table 21 Number of activated CDM groups K=3

[0296] Table 22 Number of activated CDM groups K=4

[0297] Table 23 Number of activated CDM groups K=5

[0298] Table 24 Number of activated CDM groups K=6

[0299] Table 25 Number of activated CDM groups K=7

[0300] Table 26 Number of activated CDM groups K=1

[0301] Table 27 Number of activated CDM groups K=2

[0302] Table 28 Number of activated CDM groups K=3

[0303] Table 29 Number of activated CDM groups K=4

[0304] Table 30 Number of activated CDM groups K=5

[0305] Table 31 Number of activated CDM groups K=6

[0306] Table 32 Number of activated CDM groups K=7

[0307] In actual use, only part of the content in Table 5-Table 32 may be used. For example, the network device configures the terminal device to only use part of the Rank values ​​(for example, the rank indication restriction (RI restriction) is configured), or the maximum value of the total number of transmission layers is configured (referred to as the maximum number of transmission layers, that is, the maximum value of Rank in the table), then the table may only contain the content in the rows corresponding to the partial Rank values ​​that meet the network device configuration; or, the terminal device only uses the rows in the table corresponding to the partial Rank values ​​that meet the network device configuration, and does not use other rows. For details, please refer to the above introduction to Tables 1-4, which will not be repeated here.

[0308] The network device sends the PDSCH and the DMRS on the corresponding DMRS port, which comes from the K activated CDM groups. The terminal device determines the corresponding DMRS port for each CDM group based on the number of transmission layers corresponding to each CDM group in the activated CDM groups, and then demodulates the PDSCH.

[0309] Embodiment 8:

[0310] In this embodiment, the terminal device determines the TCI state corresponding to the CDM group.

[0311] For example, the terminal device can determine the TCI status corresponding to different CDM groups in the activated CDM groups based on DCI signaling. One of the following methods can be used:

[0312] Method 1: M TCI states are indicated in the DCI signaling, and the M TCI states correspond one-to-one to the M CDM groups currently used for PDSCH transmission in the K TCI states.

[0313] In one example, the network device activates multiple TCI state groups through MAC CE, and different TCI state groups contain different numbers of TCI states. The DCI signaling is then used to indicate the group containing M TCI states, where M is the number of CDM groups currently used for PDSCH transmission.

[0314] In one example, a network device activates multiple TCI state groups through MAC CE, each TCI state group contains K TCI states (i.e., M=K), where K is the number of currently activated CDM groups indicated by the network device through high-layer signaling, and the K TCI states correspond one-to-one to the K activated CDM groups.

[0315] In one example, a network device activates multiple TCI state groups through MAC CE, each TCI state group contains M TCI states, where M is the number of CDM groups currently used for PDSCH transmission indicated by the network device through high-layer signaling; and then indicates one of the TCI state groups through DCI signaling.

[0316] Method 2: DCI signaling indicates M TCI states. The terminal device determines the TCI state corresponding to each CDM group currently used for PDSCH transmission among the K activated CDM groups based on the correspondence between TCI states and CDM groups indicated in advance by the network device through higher-layer signaling. For example, the network device may indicate that several CDM groups correspond to the first TCI state, several CDM groups correspond to the second TCI state, and so on.

[0317] Method 3: DCI signaling indicates two TCI states and a bitmap. The bitmap is used to indicate whether the TCI state corresponding to each CDM group in the K CDM groups adopts the first or second TCI state. For example, the bitmap is K bits long, with each bit corresponding to a CDM group. When a bit in the bitmap is 1, it indicates that the CDM group corresponding to the bit adopts the first TCI state; when the bit is 0, it indicates that the CDM group corresponding to the bit adopts the second TCI state. Alternatively, when a bit in the bitmap is 0, it indicates that the CDM group corresponding to the bit adopts the first TCI state; when the bit is 1, it indicates that the CDM group corresponding to the bit adopts the second TCI state.

[0318] In one implementation, CDM groups corresponding to the same TCI state are associated with the same PTRS port.

[0319] In the above embodiments, embodiments 1 to 4 introduce various ways for the terminal device to determine the K activated CDM groups. Embodiments 5 to 7 introduce various ways for the terminal device to determine the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups, and / or the DMRS ports used for PDSCH in each CDM group. Embodiment 8 introduces a specific way for the terminal device to determine the TCI state corresponding to the CDM group. The above embodiments can be combined arbitrarily. For example, by adopting any of the methods described in embodiments 1 to 4, the network device can activate a large number of CDM groups for the terminal device; and, by adopting any of the methods described in embodiments 5 to 7, the network device indicates the DMRS ports and / or the number of PDSCH transmission layers corresponding to each CDM group to the terminal device; and, by adopting embodiment 7, the network device indicates the TCI state corresponding to each CDM group to the terminal device, thereby indicating that a large number of low-port nodes are supported for joint transmission at the same time, thereby improving the throughput of downlink transmission.

[0320] The present application also provides a signal transmission method. FIG6 is a schematic flowchart of a signal transmission method 600 according to an embodiment of the present application. The method can be applied to the systems shown in FIG1-3, but is not limited thereto. The method includes at least part of the following contents.

[0321] S610. The network device determines K activated CDM groups, where K is a positive integer.

[0322] S620: The network device sends a DCI signaling, where the DCI signaling is used to determine a DMRS port for a PDSCH in a CDM group.

[0323] The above K may be greater than 3.

[0324] In some implementations, the method further includes: the network device sending a PDSCH and a DMRS on a corresponding DMRS port, where the DMRS port comes from the K CDM groups.

[0325] In some embodiments, DCI signaling is used by a terminal device to determine the number of PDSCH transmission layers corresponding to different CDM groups in K CDM groups, and to determine the DMRS port used for PDSCH in the CDM group based on the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups.

[0326] In some implementations, the DCI signaling includes first information, where the first information indicates the number of PDSCH transmission layers corresponding to each of the K CDM groups.

[0327] In some implementations, the number of PDSCH transmission layers corresponding to each CDM group ranges from {1, 2}, or {0, 1, 2}, or {1, 2, 3, 4}, or {0, 1, 2, 3, 4}, or {0, 1, 2, NULL}, or {0, 1, 2, 3, NULL}. The number of PDSCH transmission layers corresponding to each CDM group can be any value within the range.

[0328] 0 can indicate that the CDM group is not used to send DMRS, but the terminal device needs to perform rate matching on the resources occupied by the CDM group; NULL can indicate that the CDM group is not used to send DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group. 0 and Null can also be described in other ways to indicate the same meaning, for example, the two indication contents are interchangeable.

[0329] In some implementations, the DCI signaling includes second information and third information, where the second information indicates a value of K, and the third information indicates a combination of K transmission layers corresponding to the value of K.

[0330] In some implementations, the DCI signaling indicates the total number of transmission layers and the allocation of the transmission layers among the K CDM groups.

[0331] In some embodiments, the allocation of transmission layers in the K CDM groups includes: a combination of k transmission layer numbers; wherein k is a positive integer less than or equal to K; wherein,

[0332] The k transmission layers correspond to the first k CDM groups among the K CDM groups; or

[0333] The k transmission layer numbers correspond to the k CDM groups indicated by the network devices in the K CDM groups.

[0334] In some embodiments, among the k transmission layer numbers, the difference between the maximum number of transmission layers and the minimum number of transmission layers is less than or equal to 1; or, among the k transmission layer numbers, the difference between the maximum number of transmission layers and the minimum number of transmission layers is less than or equal to 2.

[0335] In some embodiments, at least one of the following is further included:

[0336] The network device sends a high-layer signaling to the terminal device, where the high-layer signaling is used to determine the activated CDM group;

[0337] The network device sends DCI signaling to the terminal device, where the DCI signaling is used to determine the activated CDM group;

[0338] The network device sends DCI signaling to the terminal device, where the DCI signaling is used to indicate the number of TCI states.

[0339] In some implementations, the network device sends higher-layer signaling to the terminal device, where the higher-layer signaling is used to determine an activated CDM group, including at least one of the following:

[0340] The network device sends a bitmap indicated by higher-layer signaling. Each bit in the bitmap corresponds to a CDM group, and each bit is used to determine whether the corresponding CDM group is an active CDM group.

[0341] The network device sends K indicated by higher-layer signaling, where K is used to determine the corresponding K activated CDM groups;

[0342] The network device sends a DMRS symbol number indicated by high-layer signaling. The DMRS symbol number is used to determine whether the CDM group on the corresponding DMRS symbol is an activated CDM group.

[0343] The network device sends RRC signaling and MAC CE, where the RRC signaling is used to determine the number of DMRS symbols, and the MAC CE is used to determine the CDM group activated on the DMRS symbols corresponding to the number of DMRS symbols.

[0344] In some implementations, the network device sends DCI signaling to the terminal device, where the DCI signaling is used to determine an activated CDM group, including at least one of the following:

[0345] The network device sends a bitmap indicated by DCI signaling. Each bit in the bitmap corresponds to a CDM group, and each bit is used to determine whether the corresponding CDM group is an activated CDM group.

[0346] The network device sends DCI signaling indicating K, where K is used to determine the corresponding K activated CDM groups;

[0347] The network device sends the number of DMRS symbols indicated by DCI signaling, and the number of DMRS symbols is used to determine whether the CDM group on the corresponding DMRS symbol is an activated CDM group.

[0348] In some implementations, the number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured for the network device.

[0349] In some implementations, the DCI signaling indicates the DMRS port used for the PDSCH in each of the K CDM groups.

[0350] The value range of the DMRS port for PDSCH in each CDM group can be {0,1,0-1}, or {0,1,0-1,Null}, or {0,1,2,3,0-1,2-3,0-2,0-3}, or {0,1,2,3,0-1,2-3,0-2,0-3,Null}. NULL can indicate that the CDM group is not used to send the DMRS of the terminal device.

[0351] In some implementations, the method further includes: the network device sending DCI signaling, where the DCI signaling is used to determine the TCI state corresponding to the CDM group.

[0352] In one example, M TCI states are indicated in the DCI signaling, and the M TCI states correspond one-to-one to the M CDM groups used for PDSCH transmission in the K CDM groups, where M is a positive integer.

[0353] In one example, N TCI states are indicated in the DCI signaling, and the N TCI states are used by the terminal device to determine the TCI state corresponding to each CDM group used for PDSCH transmission in the K CDM groups from the N TCI states according to the correspondence between the TCI state and the CDM group indicated in advance by the network device through high-level signaling; N is a positive integer.

[0354] In one example, the DCI signaling indicates a first TCI state, a second TCI state, and a bitmap, where the bitmap is used to indicate that K TCI states respectively adopt the first TCI state or the second TCI state.

[0355] In some implementations, CDM groups corresponding to the same TCI state are associated with the same PTRS port.

[0356] By adopting the signal sending method proposed in the embodiment of the present application, the network device can activate a large number of CDM groups for the terminal device and indicate the DMRS port, transmission layer number or TCI status corresponding to each CDM group, thereby supporting a large number of low-port nodes to perform joint transmission at the same time and improving the throughput of downlink transmission.

[0357] In summary, an embodiment of the present application proposes a DMRS signal indication method, in which a network device activates a CDM group for a terminal device, and indicates the CDM group currently used for DMRS transmission through DCI signaling, as well as at least one of the transmission layer, DMRS port and TCI status corresponding to each CDM group; in this way, a CDM group can be allocated to each subnode in a multi-node communication system, thereby supporting simultaneous transmission of multiple nodes in a cell-free scenario and improving the throughput of downlink transmission.

[0358] The method proposed in the embodiment of the present application can support more CDM groups, each CDM group supports multiple ports (such as each CDM group supports 2 or 4 ports), thereby supporting more DMRS ports for simultaneous transmission of multiple nodes. The embodiment of the present application proposes multiple methods for activating CDM groups, and the activated CDM groups can be used to transmit DMRS or for rate matching. The embodiment of the present application can indicate the number of PDSCH transmission layers corresponding to each activated CDM group, or the DMRS port used by each activated CDM group, or the transmission layer allocation method corresponding to the activated CDM group through DCI signaling. Furthermore, the embodiment of the present application can also indicate the TCI status corresponding to each activated CDM group through DCI signaling. Using the DCI signaling, high-layer signaling, etc. received from the network device, the terminal device can determine the CDM group activated by the network device for the terminal device, and at least one of the DMRS port, transmission layer number and TCI status corresponding to each activated CDM, thereby supporting the joint transmission of a large number of low-port nodes and improving the throughput of downlink transmission.

[0359] The present application also provides a terminal device. FIG7 is a schematic block diagram of a terminal device 700 according to an embodiment of the present application. The terminal device 700 may include:

[0360] A first determining unit 710 is configured to determine K activated CDM groups, where K is a positive integer;

[0361] A second determining unit 720 is configured to receive DCI signaling from a network device, and determine a DMRS port for the PDSCH in the CDM group according to the DCI signaling;

[0362] The demodulation unit 730 is configured to demodulate the PDSCH based on the DMRS port used for the PDSCH in the CDM group.

[0363] Among them, K can be greater than 3.

[0364] In some embodiments, the second determination unit 720 is used to determine the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups based on the DCI signaling; and determine the DMRS port used for PDSCH in the CDM group according to the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups.

[0365] In some embodiments, the DCI signaling includes first information, where the first information indicates the number of PDSCH transmission layers corresponding to each of the K CDM groups;

[0366] In some implementations, the second determining unit 720 is configured to determine, based on the first information, the number of PDSCH transmission layers corresponding to each of the K CDM groups.

[0367] In some implementations, the number of PDSCH transmission layers corresponding to each CDM group ranges from {1, 2}, or {0, 1, 2}, or {1, 2, 3, 4}, or {0, 1, 2, 3, 4}, or {0, 1, 2, NULL}, or {0, 1, 2, 3, NULL}. The number of PDSCH transmission layers corresponding to each CDM group can be any value within the range.

[0368] In some implementations, the 0 indicates that the CDM group is not used to send DMRS, but the terminal device needs to perform rate matching on the resources occupied by the CDM group;

[0369] The NULL indicates that the CDM group is not used to send DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0370] In some embodiments, the DCI signaling includes second information and third information, where the second information indicates a value of K, and the third information indicates a combination of K transmission layers corresponding to the value of K;

[0371] In some embodiments, the second determining unit 720 is configured to determine the number of PDSCH transmission layers corresponding to each of the K CDM groups according to the value of K and a combination of the number of K transmission layers corresponding to the value of K.

[0372] In some embodiments, the DCI signaling indicates the total number of transmission layers and the allocation of the transmission layers among the K CDM groups;

[0373] In some embodiments, the second determining unit 720 is configured to determine the number of PDSCH transmission layers corresponding to each of the K CDM groups according to the total number of transmission layers and the manner in which the transmission layers are allocated in the K CDM groups.

[0374] In some embodiments, the allocation of transmission layers in the K CDM groups includes: a combination of k transmission layer numbers; wherein k is a positive integer less than or equal to K; wherein,

[0375] The k transmission layers respectively correspond to the first k CDM groups in the K CDM groups; or,

[0376] The k transmission layer numbers respectively correspond to the k CDM groups indicated by the network equipment in the K CDM groups.

[0377] In some embodiments, among the k transmission layer numbers, the difference between the maximum transmission layer number and the minimum transmission layer number is less than or equal to 1; or,

[0378] Among the k transmission layer numbers, a difference between a maximum transmission layer number and a minimum transmission layer number is less than or equal to 2.

[0379] In some embodiments, when the number of PDSCH transmission layers corresponding to the CDM group is n, and n is a positive integer;

[0380] The second determination unit 720 is used to determine that the n PDSCH transmission layers of the CDM use the first n DMRS ports in the CDM group; or, according to high-layer signaling or physical layer signaling instructions, determine the n DMRS ports in the CDM group used for the n PDSCH transmission layers.

[0381] In some implementations, the first determining unit 710 is configured to determine K activated CDM groups from L CDM groups agreed upon with the network device, where L is an integer greater than or equal to 3.

[0382] In some implementations, the first determining unit 710 is configured to perform at least one of the following:

[0383] receiving a higher layer signaling from a network device, and determining an activated CDM group according to the higher layer signaling;

[0384] receiving DCI signaling from a network device, and determining an activated CDM group according to the DCI signaling;

[0385] Determining the number of activated CDM groups according to the maximum number of transmission layers configured for the network device, and determining the activated CDM groups according to the number;

[0386] The number of activated CDM groups is determined according to the number of TCI states indicated in the DCI signaling, and the activated CDM groups are determined according to the number.

[0387] In some implementations, the first determining unit 710 is configured to perform at least one of the following:

[0388] receiving a bitmap indicated by higher-layer signaling, where each bit in the bitmap corresponds to a CDM group, and the terminal device determines, based on each bit, whether the corresponding CDM group is an activated CDM group;

[0389] receiving the K indicated by higher layer signaling, and determining corresponding K activated CDM groups;

[0390] receiving a DMRS symbol number indicated by a higher layer signaling, and determining that a CDM group on a DMRS symbol corresponding to the DMRS symbol number is an activated CDM group;

[0391] Receive RRC signaling and MAC CE from the network device, determine the number of DMRS symbols according to the RRC signaling, and determine the CDM group activated on the DMRS symbol corresponding to the number of DMRS symbols according to the MAC CE.

[0392] In some implementations, the first determining unit 710 is configured to perform at least one of the following:

[0393] receiving a bitmap indicated by the DCI signaling, where each bit in the bitmap corresponds to a CDM group, and the terminal device determines, according to each bit, whether the corresponding CDM group is an activated CDM group;

[0394] receiving the K indicated by the DCI signaling, and determining corresponding K activated CDM groups;

[0395] The number of DMRS symbols indicated by the DCI signaling is received, and a CDM group on the DMRS symbols corresponding to the number of DMRS symbols is determined to be an activated CDM group.

[0396] In some implementations, the number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured for the network device.

[0397] In some embodiments, the DCI signaling respectively indicates a DMRS port for the PDSCH in each of the K CDM groups;

[0398] In some implementations, the second determining unit 720 is configured to determine, according to the DCI signaling, a DMRS port for the PDSCH in each of the K CDM groups.

[0399] In some implementations, the value range of the DMRS port for PDSCH in each CDM group is {0, 1, 0-1}, or {0, 1, 0-1, Null}, or {0, 1, 2, 3, 0-1, 2-3, 0-2, 0-3}, or {0, 1, 2, 3, 0-1, 2-3, 0-2, 0-3, Null}.

[0400] In some implementations, NULL indicates that the CDM group is not used to send the DMRS of the terminal device.

[0401] In some implementations, the second determining unit 720 is further configured to receive DCI signaling; and determine, according to the DCI signaling status, a TCI status corresponding to the CDM group.

[0402] In some implementations, the DCI signaling indicates M TCI states, the M TCI states correspond one-to-one to the M CDM groups used for PDSCH transmission in the K CDM groups, and M is a positive integer; or,

[0403] The DCI signaling indicates N TCI states, and the terminal device determines the TCI state corresponding to each CDM group used for PDSCH transmission in the K CDM groups from the N TCI states according to the correspondence between the TCI states and the CDM groups indicated in advance by the network device through high-layer signaling; N is a positive integer; or

[0404] The DCI signaling indicates a first TCI state, a second TCI state, and a bitmap, and the bitmap is used to indicate that the K TCI states respectively adopt the first TCI state or the second TCI state.

[0405] In some implementations, CDM groups corresponding to the same TCI state are associated with the same PTRS port.

[0406] The terminal device 700 of the embodiment of the present application can implement the corresponding functions of the terminal device in the aforementioned method embodiment. The processes, functions, implementation methods and beneficial effects corresponding to the various modules (sub-modules, units or components, etc.) in the terminal device can be found in the corresponding descriptions in the above-mentioned method embodiments, and will not be repeated here. It should be noted that the functions described by the various modules (sub-modules, units or components, etc.) in the terminal device of the embodiment of the application can be implemented by different modules (sub-modules, units or components, etc.) or by the same module (sub-module, unit or component, etc.).

[0407] The present application also provides a network device. FIG8 is a schematic block diagram of a network device 800 according to an embodiment of the present application. The terminal device 800 may include:

[0408] A third determining unit 810 is configured to determine K activated CDM groups, where K is a positive integer;

[0409] The sending unit 820 is configured to send DCI signaling, where the DCI signaling is used to determine a DMRS port for the PDSCH in the CDM group.

[0410] Among them, K can be greater than 3.

[0411] In some implementations, the sending unit 820 is further configured to send the PDSCH and a DMRS on a corresponding DMRS port, where the DMRS port comes from the K CDM groups.

[0412] In some embodiments, DCI signaling is used by a terminal device to determine the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups, and to determine the DMRS port used for PDSCH in the CDM group based on the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups.

[0413] In some implementations, the DCI signaling includes first information, where the first information indicates the number of PDSCH transmission layers corresponding to each of the K CDM groups.

[0414] In some implementations, the number of PDSCH transmission layers corresponding to each CDM group ranges from {1, 2}, or {0, 1, 2}, or {1, 2, 3, 4}, or {0, 1, 2, 3, 4}, or {0, 1, 2, NULL}, or {0, 1, 2, 3, NULL}. The number of PDSCH transmission layers corresponding to each CDM group can be any value within the range.

[0415] In some embodiments, 0 indicates that the CDM group is not used to send DMRS, but the terminal device needs to perform rate matching on the resources occupied by the CDM group; NULL indicates that the CDM group is not used to send DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

[0416] In some implementations, the DCI signaling includes second information and third information, where the second information indicates a value of K, and the third information indicates a combination of K transmission layers corresponding to the value of K.

[0417] In some implementations, the DCI signaling indicates the total number of transmission layers and the allocation of the transmission layers among the K CDM groups.

[0418] In some embodiments, the allocation of transmission layers in the K CDM groups includes: a combination of k transmission layer numbers; wherein k is a positive integer less than or equal to K; wherein,

[0419] The k transmission layers correspond to the first k CDM groups in the K CDM groups; or

[0420] The k transmission layer numbers respectively correspond to the k CDM groups indicated by the network device in the K CDM groups.

[0421] In some embodiments, among the k transmission layer numbers, the difference between the maximum transmission layer number and the minimum transmission layer number is less than or equal to 1; or,

[0422] Among the k transmission layer numbers, a difference between a maximum transmission layer number and a minimum transmission layer number is less than or equal to 2.

[0423] In some implementations, the sending unit 820 is further configured to perform at least one of the following:

[0424] Sending high-layer signaling to the terminal device, wherein the high-layer signaling is used to determine the activated CDM group;

[0425] Sending DCI signaling to the terminal device, where the DCI signaling is used to determine the activated CDM group;

[0426] Send DCI signaling to the terminal device, where the DCI signaling is used to indicate the number of TCI states.

[0427] In some embodiments, the sending unit 820 is configured to perform at least one of the following:

[0428] Sending a bitmap indicated by higher layer signaling, where each bit in the bitmap corresponds to a CDM group, and each bit is used to determine whether the corresponding CDM group is an activated CDM group;

[0429] Sending the K indicated by higher layer signaling, where the K is used to determine the corresponding K activated CDM groups;

[0430] Sending the number of DMRS symbols indicated by higher-layer signaling, where the number of DMRS symbols is used to determine that the CDM group on the corresponding DMRS symbol is an activated CDM group;

[0431] RRC signaling and MAC CE are sent, where the RRC signaling is used to determine the number of DMRS symbols, and the MAC CE is used to determine the CDM group activated on the DMRS symbol corresponding to the number of DMRS symbols.

[0432] In some implementations, the sending unit 820 is configured to perform at least one of the following:

[0433] Sending a bitmap indicated by DCI signaling, where each bit in the bitmap corresponds to a CDM group, and each bit is used to determine whether the corresponding CDM group is an activated CDM group;

[0434] Sending the K indicated by DCI signaling, where K is used to determine the corresponding K activated CDM groups;

[0435] The number of DMRS symbols indicated by the DCI signaling is sent, where the number of DMRS symbols is used to determine whether the CDM group on the corresponding DMRS symbol is an activated CDM group.

[0436] In some implementations, the number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured for the network device.

[0437] In some implementations, the DCI signaling indicates the DMRS port used for the PDSCH in each of the K CDM groups.

[0438] In some embodiments, the value range of the DMRS port for PDSCH in each CDM group is {0, 1, 0-1}, or {0, 1, 0-1, Null}, or {0, 1, 2, 3, 0-1, 2-3, 0-2, 0-3}, or {0, 1, 2, 3, 0-1, 2-3, 0-2, 0-3, Null}. NULL may indicate that the CDM group is not used to send the DMRS of the terminal device.

[0439] In some implementations, the sending unit 820 is further configured to send DCI signaling, where the DCI signaling is used to determine a TCI state corresponding to the CDM group.

[0440] In some implementations, the DCI signaling indicates M TCI states, the M TCI states correspond one-to-one to the M CDM groups used for PDSCH transmission in the K CDM groups, and M is a positive integer; or,

[0441] The DCI signaling indicates N TCI states, and the N TCI states are used by the terminal device to determine the TCI state corresponding to each CDM group used for PDSCH transmission in the K CDM groups from the N TCI states according to the correspondence between the TCI states and the CDM groups indicated in advance by the network device through high-layer signaling; N is a positive integer; or

[0442] The DCI signaling indicates a first TCI state, a second TCI state, and a bitmap, where the bitmap is used to indicate that the K TCI states respectively adopt the first TCI state or the second TCI state.

[0443] In some implementations, CDM groups corresponding to the same TCI state are associated with the same PTRS port.

[0444] The network device 800 of the embodiment of the present application can implement the corresponding functions of the network device in the aforementioned method embodiment. The processes, functions, implementation methods and beneficial effects corresponding to each module (sub-module, unit or component, etc.) in the network device can be found in the corresponding description in the above method embodiment, and will not be repeated here. It should be noted that the functions described in the various modules (sub-module, unit or component, etc.) in the network device of the embodiment of the application can be implemented by different modules (sub-module, unit or component, etc.) or by the same module (sub-module, unit or component, etc.).

[0445] Figure 9 is a schematic structural diagram of a communication device 900 according to an embodiment of the present application. The communication device 900 includes a processor 910, which can call and run a computer program from a memory to enable the communication device 900 to implement the method in the embodiment of the present application.

[0446] In one embodiment, the communication device 900 may further include a memory 920. The processor 910 may call and execute a computer program from the memory 920 to enable the communication device 900 to implement the method in the embodiment of the present application.

[0447] The memory 920 may be a separate device independent of the processor 910 , or may be integrated into the processor 910 .

[0448] In one embodiment, the communication device 900 may further include a transceiver 930 , and the processor 910 may control the transceiver 930 to communicate with other devices. Specifically, the transceiver 930 may send information or data to other devices, or receive information or data sent by other devices.

[0449] The transceiver 930 may include a transmitter and a receiver. The transceiver 930 may further include an antenna, and the number of antennas may be one or more.

[0450] In one embodiment, the communication device 900 may be a terminal device of an embodiment of the present application, and the communication device 900 may implement the corresponding processes implemented by the terminal device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0451] In one embodiment, the communication device 900 may be a network device of an embodiment of the present application, and the communication device 900 may implement the corresponding processes implemented by the network device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0452] 10 is a schematic structural diagram of a chip 1000 according to an embodiment of the present application. The chip 1000 includes a processor 1010, which can call and execute a computer program from a memory to implement the method according to the embodiment of the present application.

[0453] In one embodiment, the chip 1000 may further include a memory 1020. The processor 1010 may call and execute a computer program from the memory 1020 to implement the method executed by the terminal device or the network device in the embodiment of the present application.

[0454] The memory 1020 may be a separate device independent of the processor 1010 , or may be integrated into the processor 1010 .

[0455] In one embodiment, the chip 1000 may further include an input interface 1030. The processor 1010 may control the input interface 1030 to communicate with other devices or chips, and specifically, may obtain information or data sent by other devices or chips.

[0456] In one embodiment, the chip 1000 may further include an output interface 1040. The processor 1010 may control the output interface 1040 to communicate with other devices or chips, and specifically, may output information or data to other devices or chips.

[0457] In one embodiment, the chip can be applied to the terminal device in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the terminal device in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0458] In one embodiment, the chip can be applied to the network device in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the network device in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0459] The chips used in the terminal device and the network device can be the same chip or different chips.

[0460] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0461] The processor mentioned above may be a general-purpose processor, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or other programmable logic devices, transistor logic devices, discrete hardware components, etc. The general-purpose processor mentioned above may be a microprocessor or any conventional processor, etc.

[0462] The memory mentioned above may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM).

[0463] It should be understood that the above-mentioned memories are exemplary but not restrictive. For example, the memories in the embodiments of the present application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM RAM (DR RAM), etc. In other words, the memories in the embodiments of the present application are intended to include, but are not limited to, these and any other suitable types of memories.

[0464] FIG11 is a schematic block diagram of a communication system 1100 according to an embodiment of the present application. The communication system 1100 includes a terminal device 1110 and a network device 1120 .

[0465] Terminal device 1110 includes:

[0466] A first determining unit, configured to determine K activated CDM groups, where K is a positive integer;

[0467] A second determining unit is configured to receive DCI signaling from a network device, and determine a DMRS port for PDSCH in the CDM group according to the DCI signaling;

[0468] The demodulation unit is configured to demodulate the PDSCH based on the DMRS port used for the PDSCH in the CDM group.

[0469] Network device 1120 includes:

[0470] a third determining unit, configured to determine K activated CDM groups, where K is a positive integer;

[0471] The sending unit is used to send DCI signaling, where the DCI signaling is used to determine the DMRS port used for the PDSCH in the CDM group.

[0472] The terminal device 1110 can be used to implement the corresponding functions implemented by the terminal device in the above method, and the network device 1120 can be used to implement the corresponding functions implemented by the network device in the above method. For the sake of brevity, they are not described here in detail.

[0473] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function in accordance with the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode to another website, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0474] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A demodulation method, comprising: The terminal device determines K activated code division multiplexing CDM groups, where K is a positive integer; The terminal device receives a first downlink control information DCI signaling from a network device, and determines a demodulation reference signal DMRS port for a physical downlink shared channel PDSCH in the CDM group according to the first DCI signaling; The terminal device demodulates the PDSCH based on the DMRS port used for the PDSCH in the CDM group.

2. The method according to claim 1, wherein: The terminal device determines, according to the first DCI signaling, a DMRS port for a PDSCH in the CDM group, including: The terminal device determines the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups based on the first DCI signaling; and determines the DMRS port used for PDSCH in the CDM group according to the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups.

3. The method according to claim 2, wherein: The first DCI signaling includes first information, and the first information respectively indicates the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups; The terminal device determines the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups based on the first DCI signaling, including: the terminal device determines the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups according to the first information.

4. The method according to claim 3, wherein: The value range of the number of PDSCH transmission layers corresponding to each CDM group is {1,2}, or {0,1,2}, or {1,2,3,4}, or {0,1,2,3,4}, or {0,1,2,NULL}, or {0,1,2,3,NULL}.

5. The method according to claim 4, wherein: The 0 indicates that the CDM group is not used to send DMRS, but the terminal device needs to perform rate matching on the resources occupied by the CDM group; The NULL indicates that the CDM group is not used to send DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

6. The method according to claim 2, wherein: The first DCI signaling includes second information and third information, the second information indicates a value of K, and the third information indicates a combination of K transmission layers corresponding to the value of K; The terminal device determines the number of PDSCH transmission layers corresponding to the CDM group based on the first DCI signaling, including: The terminal device determines the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups according to the value of K and the combination of the number of K transmission layers corresponding to the value of K.

7. The method according to claim 2, wherein: The first DCI signaling indicates the total number of transmission layers and the allocation manner of the transmission layers in the K CDM groups; The terminal device determines the number of PDSCH transmission layers corresponding to the CDM group based on the first DCI signaling, including: The terminal device determines the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups according to the total number of transmission layers and the allocation method of the transmission layers in the K CDM groups.

8. The method according to claim 7, wherein: The allocation method of the transmission layer in the K CDM groups includes: a combination of k transmission layer numbers; wherein k is a positive integer less than or equal to K; wherein, The k transmission layers respectively correspond to the first k CDM groups among the K CDM groups; or, The k transmission layer numbers respectively correspond to the k CDM groups indicated by the network devices in the K CDM groups.

9. The method according to claim 8, wherein: Among the k transmission layer numbers, the difference between the maximum number of transmission layers and the minimum number of transmission layers is less than or equal to 1; or, Among the k transmission layer numbers, a difference between a maximum transmission layer number and a minimum transmission layer number is less than or equal to 2.

10. The method according to any one of claims 2 to 9, wherein: When the number of PDSCH transmission layers corresponding to the CDM group is n, where n is a positive integer; The terminal device determines that the n PDSCH transmission layers of the CDM use the first n DMRS ports in the CDM group; or, The terminal device determines n DMRS ports in the CDM group for the n PDSCH transmission layers according to high-layer signaling or physical layer signaling instructions.

11. The method according to any one of claims 1 to 10, wherein: The terminal device determines K activated CDM groups, including: The terminal device determines K activated CDM groups from L CDM groups agreed upon with the network device, where L is an integer greater than or equal to 3.

12. The method according to any one of claims 1 to 10, wherein: The terminal device determines K activated CDM groups, including at least one of the following: The terminal device receives a high-layer signaling from a network device, and determines an activated CDM group according to the high-layer signaling; The terminal device receives a second DCI signaling from the network device, and determines an activated CDM group according to the second DCI signaling; The terminal device determines the number of activated CDM groups according to the maximum number of transmission layers configured by the network device, and determines the activated CDM groups according to the number; The terminal device determines the number of activated CDM groups according to the number of TCI states indicated by the transmission configuration indication in the third DCI signaling, and determines the number of activated CDM groups according to the number.

13. The method according to claim 12, wherein: The terminal device receives a high-layer signaling from a network device, and determines an activated CDM group according to the high-layer signaling, including at least one of the following: The terminal device receives a bitmap indicated by high-level signaling, each bit in the bitmap corresponds to a CDM group, and the terminal device determines whether the corresponding CDM group is an activated CDM group according to each bit; The terminal device receives the K indicated by the high-level signaling, and determines the corresponding K activated CDM groups; The terminal device receives the number of DMRS symbols indicated by high-level signaling, and determines that the CDM group on the DMRS symbol corresponding to the number of DMRS symbols is an activated CDM group; The terminal device receives radio resource control RRC signaling and media access control element MAC CE from the network device, determines the number of DMRS symbols according to the RRC signaling, and determines the CDM group activated on the DMRS symbol corresponding to the number of DMRS symbols according to the MAC CE.

14. The method according to claim 12, wherein: The terminal device receives a second DCI signaling from a network device, and determines an activated CDM group according to the second DCI signaling, including at least one of the following: The terminal device receives a bitmap indicated by the second DCI signaling, each bit in the bitmap corresponds to a CDM group, and the terminal device determines whether the corresponding CDM group is an activated CDM group according to each bit; The terminal device receives the K indicated by the second DCI signaling, and determines the corresponding K activated CDM groups; The terminal device receives the number of DMRS symbols indicated by the second DCI signaling, and determines that the CDM group on the DMRS symbol corresponding to the number of DMRS symbols is an activated CDM group; The terminal device receives radio resource control RRC signaling and the second DCI signaling from the network device, determines the number of DMRS symbols according to the RRC signaling, and determines the CDM group activated on the DMRS symbol corresponding to the number of DMRS symbols according to the second DCI signaling.

15. The method according to any one of claims 1 to 14, wherein: The number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured by the network device.

16. The method according to any one of claims 1 to 15, wherein: The first DCI signaling respectively indicates a DMRS port for PDSCH in each CDM group of the K CDM groups; The determining the DMRS port for PDSCH in the CDM group according to the first DCI signaling includes: determining the DMRS port for PDSCH in each CDM group in the K CDM groups according to the first DCI signaling.

17. The method according to claim 16, wherein: The value range of the DMRS port used for PDSCH in each CDM group is {0,1,0-1}, or {0,1,0-1,Null}, or {0,1,2,3,0-1,2-3,0-2,0-3}, or {0,1,2,3,0-1,2-3,0-2,0-3,Null}.

18. The method according to claim 17, wherein: The NULL indicates that the CDM group is not used to send the DMRS of the terminal device.

19. The method according to any one of claims 1-18 further includes: the terminal device receiving a fourth DCI signaling; and determining a TCI state corresponding to the CDM group according to the fourth DCI signaling.

20. The method according to claim 19, wherein: The fourth DCI signaling indicates M TCI states, the M TCI states correspond one-to-one to M CDM groups used for PDSCH transmission in the K CDM groups, and M is a positive integer; or, The fourth DCI signaling indicates N TCI states, and the terminal device determines the TCI state corresponding to each CDM group used for PDSCH transmission in the K CDM groups from the N TCI states according to the correspondence between the TCI state and the CDM group indicated in advance by the network device through high-layer signaling; N is a positive integer; or, The fourth DCI signaling indicates a first TCI state, a second TCI state and a bitmap, and the bitmap is used to indicate that the K TCI states respectively adopt the first TCI state or the second TCI state.

21. The method according to claim 19 or 20, wherein: The CDM groups corresponding to the same TCI state are associated with the same phase tracking reference signal PTRS port.

22. The method according to any one of claims 1 to 21, wherein: The K is greater than 3.

23. A signal sending method, comprising: The network device determines K activated CDM groups, where K is a positive integer; The network device sends a first DCI signaling, where the first DCI signaling is used to determine the DMRS for the PDSCH in the CDM group port.

24. The method according to claim 23, further comprising, the network device transmitting the PDSCH and a DMRS on a corresponding DMRS port, the DMRS port being from the K CDM groups.

25. The method according to claim 23 or 24, wherein: The first DCI signaling is used by the terminal device to determine the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups, and to determine the DMRS port used for PDSCH in the CDM group according to the number of PDSCH transmission layers corresponding to different CDM groups in the K CDM groups.

26. The method according to claim 25, wherein: The first DCI signaling includes first information, and the first information indicates the number of PDSCH transmission layers corresponding to each CDM group in the K CDM groups.

27. The method according to claim 26, wherein: The value range of the number of PDSCH transmission layers corresponding to each CDM group is {1,2}, or {0,1,2}, or {1,2,3,4}, or {0,1,2,3,4}, or {0,1,2,NULL}, or {0,1,2,3,NULL}.

28. The method according to claim 27, wherein: The 0 indicates that the CDM group is not used to send DMRS, but the terminal device needs to perform rate matching on the resources occupied by the CDM group; The NULL indicates that the CDM group is not used to send DMRS, and the terminal device does not need to perform rate matching on the resources occupied by the CDM group.

29. The method according to claim 25, wherein: The first DCI signaling includes second information and third information, wherein the second information indicates a value of K, and the third information indicates a combination of K transmission layers corresponding to the value of K.

30. The method of claim 25, wherein: The first DCI signaling indicates the total number of transmission layers and the allocation method of the transmission layers in the K CDM groups.

31. The method according to claim 30, wherein: The allocation method of the transmission layer in the K CDM groups includes: a combination of k transmission layer numbers; wherein k is a positive integer less than or equal to K; wherein, The k transmission layers respectively correspond to the first k CDM groups among the K CDM groups; or, The k transmission layer numbers respectively correspond to the k CDM groups indicated by the network devices in the K CDM groups.

32. The method according to claim 31, wherein: Among the k transmission layer numbers, the difference between the maximum number of transmission layers and the minimum number of transmission layers is less than or equal to 1; or, Among the k transmission layer numbers, a difference between a maximum transmission layer number and a minimum transmission layer number is less than or equal to 2.

33. The method according to any one of claims 23 to 32, further comprising at least one of the following: The network device sends a high-layer signaling to the terminal device, where the high-layer signaling is used to determine an activated CDM group; The network device sends a second DCI signaling to the terminal device, where the second DCI signaling is used to determine an activated CDM group; The network device sends a third DCI signaling to the terminal device, where the third DCI signaling is used to indicate the number of TCI states.

34. The method of claim 33, wherein: The network device sends a high-layer signaling to the terminal device, where the high-layer signaling is used to determine the activated CDM group, including at least one of the following: The network device sends a bitmap indicated by high-layer signaling, each bit in the bitmap corresponds to a CDM group, and each bit is used to determine whether the corresponding CDM group is an activated CDM group; The network device sends the K indicated by the high-layer signaling, where the K is used to determine the corresponding K activated CDM groups; The network device sends a DMRS symbol number indicated by a high-level signaling, where the DMRS symbol number is used to determine that a CDM group on a corresponding DMRS symbol is an activated CDM group; The network device sends RRC signaling and MAC CE, the RRC signaling is used to determine the number of DMRS symbols, and the MAC CE is used to determine the CDM group activated on the DMRS symbol corresponding to the number of DMRS symbols.

35. The method of claim 32, wherein: The network device sends a second DCI signaling to the terminal device, where the second DCI signaling is used to determine the activated CDM group, including at least one of the following: The network device sends a bitmap indicated by the second DCI signaling, each bit in the bitmap corresponds to a CDM group, and each bit is used to determine whether the corresponding CDM group is an activated CDM group; The network device sends the K indicated by the second DCI signaling, where the K is used to determine the corresponding K activated CDM groups; The network device sends a DMRS symbol number indicated by a second DCI signaling, where the DMRS symbol number is used to determine whether a CDM group on a corresponding DMRS symbol is an activated CDM group.

36. The method according to any one of claims 1 to 35, wherein: The number K of activated CDM groups is less than or equal to the maximum number of transmission layers configured by the network device.

37. The method according to any one of claims 23 to 36, wherein: The first DCI signaling respectively indicates a DMRS port used for PDSCH in each CDM group of the K CDM groups.

38. The method of claim 37, wherein: The value range of the DMRS port used for PDSCH in each CDM group is {0,1,0-1}, or {0,1,0-1,Null}, or {0,1,2,3,0-1,2-3,0-2,0-3}, or {0,1,2,3,0-1,2-3,0-2,0-3,Null}.

39. The method of claim 38, wherein: The NULL indicates that the CDM group is not used to send the DMRS of the terminal device.

40. The method according to any one of claims 23-39 further includes: the network device sending a fourth DCI signaling, wherein the fourth DCI signaling is used to determine the TCI state corresponding to the CDM group.

41. The method according to any one of claims 23 to 40, wherein: The fourth DCI signaling is used to determine the TCI state corresponding to the CDM group, including: The fourth DCI signaling indicates M TCI states, the M TCI states correspond one-to-one to M CDM groups used for PDSCH transmission in the K CDM groups, and M is a positive integer; or, The fourth DCI signaling indicates N TCI states, and the N TCI states are used by the terminal device to determine the TCI state corresponding to each CDM group used for PDSCH transmission in the K CDM groups from the N TCI states according to the correspondence between the TCI state and the CDM group indicated in advance by the network device through high-level signaling; N is a positive integer; or, The fourth DCI signaling indicates a first TCI state, a second TCI state and a bitmap, and the bitmap is used to indicate that the K TCI states respectively adopt the first TCI state or the second TCI state.

42. The method according to claim 40 or 41, wherein: CDM groups corresponding to the same TCI state are associated with the same PTRS port.

43. The method according to any one of claims 23 to 42, wherein: The K is greater than 3.

44. A terminal device, comprising: A first determining unit, configured to determine K activated CDM groups, where K is a positive integer; A second determining unit is used to receive a first DCI signaling from a network device, and determine a DMRS port for the PDSCH in the CDM group according to the first DCI signaling; The demodulation unit is used to demodulate the PDSCH based on the DMRS port used for the PDSCH in the CDM group.

45. A network device comprising: A third determining unit, configured to determine K activated CDM groups, where K is a positive integer; A sending unit is used to send a first DCI signaling, where the first DCI signaling is used to determine a DMRS port for a PDSCH in the CDM group.

46. ​​A communication device comprising: A processor, a memory and a transceiver, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory and control the transceiver so that the communication device executes the method as described in any one of claims 1 to 22 or any one of claims 23 to 43.

47. A chip, comprising: A processor, configured to call and run a computer program from a memory so that a device equipped with the chip executes a method as claimed in any one of claims 1 to 22 or any one of claims 23 to 43.

48. A computer-readable storage medium for storing a computer program, which, when executed by a device, causes the device to perform the method as claimed in any one of claims 1 to 22 or any one of claims 23 to 43.

49. A computer program product comprising computer program instructions for causing a computer to perform the method of any one of claims 1 to 22 or any one of claims 23 to 43.

50. A computer program causing a computer to perform the method of any one of claims 1 to 22 or any one of claims 23 to 43.

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