Communication method and communication apparatus

Abstract

A communication method and a communication apparatus, relating to the technical field of communications. The method comprises: sending first indication information to a terminal, the first indication information being used for indicating a port set for transmitting additional DMRSs, and frequency domain resources occupied by additional DMRSs transmitted by ports in the port set for the additional DMRSs being different from at least one of frequency domain resources occupied by transmission of front-load DMRSs; and sending the additional DMRSs to the terminal by means of the ports in the port set for the additional DMRSs. The method can increase the DMRS sending density, so that when a terminal performs channel estimation by using received DMRSs, the channel estimation accuracy can be improved.

Description

Communication methods and communication devices

[0001] This application claims priority to Chinese Patent Application No. 202510114631.4, filed with the State Intellectual Property Office of China on January 22, 2025, entitled "Communication Method and Communication Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, specifically to a communication method and a communication device. Background Technology

[0003] In wireless communication systems, a demodulation reference signal (DMRS) is used to estimate the data channel. If the terminal's channel conditions are poor or its movement speed is high, the network device will also configure an additional demodulation reference signal (DMRS) for the terminal to improve the quality of the terminal's channel estimation. That is, in each time slot, the first DMRS in terms of time is called the pre-DMRS, and in addition to the pre-DMRS, additional DMRS may also be included.

[0004] Currently, improving the accuracy of channel estimation using DMRS by terminals is an issue that needs attention. Summary of the Invention

[0005] This application provides a communication method that can improve the accuracy of channel estimation using DMRS by terminal devices.

[0006] In a first aspect, a communication method is provided, the method comprising: sending first indication information to a terminal, the first indication information being used to indicate a set of ports for transmitting additional DMRS, wherein at least one of the frequency domain resources occupied by the additional DMRS transmitted by the ports in the set of additional DMRS is different from the frequency domain resources occupied by the pre-transmission DMRS; and sending the additional DMRS to the terminal through the ports in the set of additional DMRS.

[0007] For example, the communication method can be implemented by a network device, or by modules, units, processors, circuits, chips or chip systems included in the network device.

[0008] The method provided in this application allows a network device to increase the density of transmitted DMRS by using frequency domain resources occupied by additional DMRS transmitted through ports in the port set of additional DMRS that are different from at least one of the frequency domain resources occupied by the transmission front DMRS. This increases the channel estimation accuracy when the terminal uses the received DMRS to perform channel estimation.

[0009] In a second aspect, a communication method is provided, the method comprising: receiving first indication information, the first indication information being used to indicate a set of ports for transmitting additional DMRS, wherein at least one of the frequency domain resources occupied by ports in the set of additional DMRS for transmitting additional DMRS is different from the frequency domain resources occupied by ports for transmitting prior DMRS; and receiving additional DMRS on time-frequency resources corresponding to the additional DMRS ports in the set of additional DMRS according to the first indication information.

[0010] For example, the entity executing the communication method can be a terminal, which can be a terminal device, a component (chip, chip system, or processor) that supports the terminal device in implementing the method, or a logic module or software that can implement all or part of the functions of the terminal device.

[0011] The method provided in this application involves a port transmission frequency domain resource occupied by the additional DMRS in the port set of the additional DMRS that is different from the frequency domain resource occupied by the pre-transmission DMRS. This increases the density of DMRS received by the terminal, thereby improving the accuracy of channel estimation when the terminal uses the received DMRS.

[0012] In some embodiments, the frequency domain resources occupied by the port transmission of the additional DMRS in the set of transmission additional DMRS ports are related to the frequency domain resources occupied by the transmission of the preceding DMRS, the subcarrier spacing of the preceding DMRS, and the number of configured additional DMRS symbols.

[0013] In this embodiment, based on the frequency domain resources occupied by the pre-DMRS, the frequency hopping of the additional DMRS is related to the subcarrier spacing of the pre-DMRS and the number of additional DMRS symbols.

[0014] In some embodiments, the time-domain units of two adjacent DMRS occupy the same offset of frequency-domain resources. The time-domain units of two adjacent DMRS include: two additional DMRS time-domain units that are adjacent in the time domain, or the time-domain units of a preceding DMRS and the time-domain units of an additional DMRS that are adjacent in the time domain.

[0015] In the embodiments of this application, the frequency domain resources occupied by the time domain units of two adjacent DMRS in the time domain are offset by the same amount, which can make the additional DMRS offset uniformly, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0016] In some embodiments, the offsets between the frequency domain resources occupied by the transmission of the pre-DMRS and the frequency domain resources occupied by the transmission of the first additional DMRS, the offsets between the frequency domain resources occupied by the transmission of the second additional DMRS and the frequency domain resources occupied by the transmission of the first additional DMRS, and the offsets between the frequency domain resources occupied by the transmission of the third additional DMRS and the frequency domain resources occupied by the transmission of the second additional DMRS are the same. The time domain resources occupied by the first additional DMRS are earlier than the time domain resources occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than the time domain resources occupied by the third additional DMRS.

[0017] In this embodiment of the application, when three additional DMRSs are configured, the offsets of the frequency domain resources occupied by the transmission front DMRS and the frequency domain resources occupied by the transmission first additional DMRS, the offsets of the frequency domain resources occupied by the transmission second additional DMRS and the frequency domain resources occupied by the transmission first additional DMRS, and the offsets of the frequency domain resources occupied by the transmission third additional DMRS and the frequency domain resources occupied by the transmission second additional DMRS are the same. This allows the first additional DMRS, the second additional DMRS, and the third additional DMRS to be offset evenly, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0018] In some embodiments, the additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the l-th additional DMRS satisfies the following formula:

[0019] Where X is the maximum number of DMRS ports that can be used for DMRS transmission; n = 0, 1, ...; Δ is the number of subcarrier intervals; S is the length of the frequency domain OCC used by the DMRS; k' = 0, 1, ..., S-1; r is the CDM group index where the transmission front-end DMRS is located; L is the total number of DMRS symbols; the resources occupied by the transmission front-end DMRS include the index l = l' of OFDM symbols, where l' = 0, 1, 2, ..., L-1.

[0020] In the embodiments of this application, the above formula can be used to achieve uniform offset of the first additional DMRS, the second additional DMRS, and the third additional DMRS, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0021] In some embodiments, the frequency domain resources occupied by the transmission of the preceding DMRS are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS, and the frequency domain resources occupied by the transmission of the second additional DMRS are adjacent to the frequency domain resources occupied by the transmission of the third additional DMRS. The offset between the frequency domain resources occupied by the transmission of the first additional DMRS and the frequency domain resources occupied by the transmission of the second additional DMRS is related to the number of subcarrier intervals. The time domain resources occupied by the first additional DMRS are earlier than the frequency domain resources occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than the frequency domain resources occupied by the third additional DMRS.

[0022] In this embodiment, the frequency domain resources occupied by the transmission of the pre-DMRS are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS, and the frequency domain resources occupied by the transmission of the second additional DMRS are adjacent to the frequency domain resources occupied by the transmission of the third additional DMRS. This allows the REs to be connected in pairs, making them more robust against noise.

[0023] In some embodiments, the index k of the subcarrier in the additional DMRS port set that transmits the frequency domain resources occupied by the first additional DMRS satisfies the following formula:

[0024] The subcarrier index k for transmitting the frequency domain resources occupied by the second additional DMRS satisfies the following formula:

[0025] The index k of the subcarriers transmitting the frequency domain resources occupied by the third additional DMRS satisfies the following formula:

[0026] In the embodiments of this application, based on the above formula, the frequency domain resources occupied by the transmission front DMRS and the frequency domain resources occupied by the transmission first additional DMRS are adjacent, and the frequency domain resources occupied by the transmission second additional DMRS and the frequency domain resources occupied by the transmission third additional DMRS are adjacent, which can make the REs connected together in pairs, making them more robust against noise.

[0027] In some embodiments, the additional DMRS is configured on two adjacent DMRS symbols, and the offset between the frequency domain resources occupied by the transmission of the preceding DMRS group and the frequency domain resources occupied by the transmission of the first additional DMRS group is related to the number of subcarrier intervals.

[0028] In this embodiment, the first additional DMRS group is offset based on the frequency domain resources occupied by the preceding DMRS group. The offset is related to the subcarrier spacing, so that the first additional DMRS group can be offset evenly, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0029] In some embodiments, the additional DMRS is configured on two adjacent DMRS symbols, and the frequency domain resources occupied by the transmission of the front DMRS port group are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS group.

[0030] In this embodiment, the first additional DMRS group is offset by 1 based on the frequency domain resources occupied by the pre-DMRS group, so that the frequency domain resources occupied by the first additional DMRS group and the frequency domain resources occupied by the pre-DMRS group are adjacent, which can connect the REs in pairs, making them more robust against noise.

[0031] In some embodiments, the index k of the subcarriers in the additional DMRS port set that transmit the frequency domain resources occupied by the first additional DMRS group satisfies the following formula:

[0032] in, Or A = 1.

[0033] In the embodiments of this application, the above formula can be used to make the frequency domain resources occupied by the first additional DMRS group uniformly offset from the frequency domain resources occupied by the preceding DMRS group, or the above formula can be used to make the frequency domain resources occupied by the first additional DMRS group and the frequency domain resources occupied by the preceding DMRS group adjacent.

[0034] In some embodiments, the frequency domain resources occupied by the transmission of the first DMRS are the same as those occupied by the transmission of the second additional DMRS. The offset between the frequency domain resources occupied by the transmission of the second additional DMRS and those occupied by the transmission of the first DMRS is related to the number of subcarrier intervals. The frequency domain resources occupied by the transmission of the third additional DMRS are the same as those occupied by the transmission of the first additional DMRS. The time domain resources occupied by the first additional DMRS are earlier than those occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than those occupied by the third additional DMRS.

[0035] In this embodiment, the frequency domain resources occupied by the first additional DMRS and the third additional DMRS are offset based on the frequency domain resources occupied by the preceding DMRS, while the frequency domain resources occupied by the second additional DMRS remain unchanged. This improves the channel estimation accuracy while reducing signaling overhead.

[0036] In some embodiments, the additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the 2Nth additional DMRS satisfies the following formula, where N is greater than or equal to 1 and N is an integer:

[0037] The index k of the subcarrier that transmits the frequency domain resources occupied by the (2N-1)th additional DMRS satisfies the following formula:

[0038] In the embodiments of this application, the above formula can be used to offset the frequency domain resources occupied by the first additional DMRS and the third additional DMRS based on the frequency domain resources occupied by the preceding DMRS, while the frequency domain resources occupied by the second additional DMRS remain unchanged, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0039] Thirdly, a communication device is provided, comprising: a unit for performing each step in any possible implementation of the first to second aspects above.

[0040] Fourthly, a communication device is provided, the communication device including at least one processor coupled to a memory for storing programs or instructions, which, when executed by the processor, perform a method in any possible implementation of the first to second aspects above.

[0041] Fifthly, a communication device is provided, the communication device including at least one processor and a memory coupled together, the memory storing program instructions, which, when executed by the processor, perform a method in any of the possible implementations of the first to second aspects above.

[0042] In a sixth aspect, a communication device is provided, the communication device including at least one processor and an interface circuit for transmitting and / or receiving signals, such that the processor performs the method in any of the possible implementations of the first to second aspects above.

[0043] In a seventh aspect, a communication system is provided, comprising a network device and a terminal, the network device being configured to perform the method in any possible implementation of the first aspect above, and the terminal being configured to perform the method in any possible implementation of the second aspect above.

[0044] Optionally, the terminal can be a terminal device.

[0045] Eighthly, a computer program product is provided, comprising a computer program that, when executed by a processor, performs a method in any possible implementation of any of the first to second aspects.

[0046] Ninthly, a computer-readable storage medium is provided, which stores a computer program that, when executed, performs the method in any of the possible implementations of the first to second aspects above.

[0047] In a tenth aspect, a chip is provided, comprising: a processor for calling and running a computer program from a memory, causing a communication device on which the chip is installed to perform the methods in any of the possible implementations of the first to second aspects above. Attached Figure Description

[0048] Figure 1 shows a schematic diagram of an OFDM time-frequency resource provided in an embodiment of this application.

[0049] Figure 2 shows a schematic diagram of DMRS orthogonalization through different antenna port time slots provided in an embodiment of this application.

[0050] Figure 3 shows a schematic diagram of the single-symbol DMRS configuration 1 supported by the existing NR.

[0051] Figure 4 shows a schematic diagram of dual-symbol DMRS configuration 1 supported by the existing NR.

[0052] Figure 5 shows a schematic diagram of the single-symbol DMRS configuration 2 supported by the existing NR.

[0053] Figure 6 shows a schematic diagram of the dual-symbol DMRS configuration 2 supported by the existing NR.

[0054] Figure 7 shows a schematic diagram of subcarrier interference in a high-speed scenario.

[0055] Figure 8 shows a schematic diagram of an additional DMRS location provided in an embodiment of this application.

[0056] Figure 9 shows a schematic diagram of a communication system provided in an embodiment of this application.

[0057] Figure 10 shows a schematic diagram of another communication system provided in an embodiment of this application.

[0058] Figure 11 shows a schematic diagram of another example of a communication system provided in an embodiment of this application.

[0059] Figure 12 shows a schematic flowchart of a communication method 1200 provided in an embodiment of this application.

[0060] Figure 13 shows a schematic diagram of an example of DMRS transmission.

[0061] Figure 14 shows a schematic diagram of another example of DMRS transmission.

[0062] Figure 15 shows a schematic diagram of another example of DMRS transmission.

[0063] Figure 16 shows a schematic diagram of another example of DMRS transmission.

[0064] Figure 17 shows a schematic diagram of the block error rate (BLER) performance of a 4-port system.

[0065] Figure 18 shows a schematic block diagram of a communication device 1800 provided in an embodiment of this application.

[0066] Figure 19 shows a schematic block diagram of another communication device 1900 provided in an embodiment of this application.

[0067] Figure 20 shows a schematic diagram of the structure of a network device 2000 provided in an embodiment of this application.

[0068] Figure 21 shows a schematic diagram of a chip system provided in an embodiment of this application. Detailed Implementation

[0069] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0070] The technical solutions of this application embodiment can be applied to various communication systems, such as: Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, 5th Generation (5G) system, or future evolved communication systems (such as 6G), etc.

[0071] In this application, the terminal device can refer to user equipment, 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 equipment. The terminal device can also be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, vehicle-mounted device, wearable device, terminal device in a 5G network, or terminal device in a future evolved network, etc. This application does not limit the scope of the terminal device.

[0072] The network device in this application embodiment can be a device for communicating with terminal devices. The network device can be a base station (BTS) in a global system for mobile communications (GSM) or code division multiple access (CDMA) system, a base station (NodeB, NB) in a wideband code division multiple access (WCDMA) system, an evolved base station (eNB or eNodeB) in an LTE system, or a radio controller in a cloud radio access network (CRAN) scenario. Alternatively, the network device can be a relay station, access point, vehicle-mounted device, wearable device, or a network device in a 5G network or a network device in a future evolved network, etc. The embodiments of this application are not limited to these.

[0073] In the embodiments of this application, the terminal device or network device may include a hardware layer, and optionally, a software layer running on the hardware layer. The hardware layer may include a processor, and may also include hardware such as a memory management unit (MMU) or memory (also called main memory). The software layer stores computer instructions that facilitate the implementation of the methods in the various embodiments of this application. The embodiments of this application do not particularly limit the specific structure or hierarchy of the executing entity of the methods provided in the embodiments of this application. Any device that can communicate according to the methods provided in the embodiments of this application by running a program that records the code of the methods provided in the embodiments of this application can be considered a terminal device or network device implementing the embodiments of this application. For example, the executing entity of the methods provided in the embodiments of this application may be a communication module (e.g., a modem), a system-on-a-chip (SoC), or other functional modules in the terminal device or network device.

[0074] Furthermore, various aspects or features of this application can be implemented as methods, apparatus, or articles of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" as used herein encompasses a computer program accessible from any computer-readable device, carrier, or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks, or magnetic tapes), optical discs (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards, and flash memory devices (e.g., erasable programmable read-only memory (EPROMs), cards, sticks, or key drives, etc.). Additionally, the various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and / or carrying instructions and / or data.

[0075] In the description of the embodiments of this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can represent A or B. "And / or" in the embodiments of this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, in the description of the embodiments of this application, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. Additionally, to facilitate a clear description of the technical solutions of the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or the order of execution, and that the words "first" and "second" do not necessarily imply that they are different.

[0076] In the various method embodiments of this application, the order of the sequence numbers does not imply the order of execution. The execution order should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0077] It is understood that in the embodiments of this application, descriptions such as "under the circumstances," "if," "when," and "if..." can be used interchangeably. Furthermore, these descriptions all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not limited to a specific time, nor do they require any judgment action during implementation, nor do they imply any other limitations.

[0078] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0079] In the embodiments of this application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments of this application, and in the various implementation methods / methods / implementations within each embodiment, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments and between the various implementation methods / methods / implementations within each embodiment are consistent and can be mutually referenced. The technical features in different embodiments and the various implementation methods / methods / implementations within each embodiment can be combined according to their inherent logical relationships to form new embodiments, implementation methods, methods, or implementation approaches. The embodiments of this application described below do not constitute a limitation on the scope of protection of this application.

[0080] In current wireless communication systems, orthogonal frequency division multiplexing (OFDM) is generally used as the signal modulation method.

[0081] Figure 1 is a schematic diagram of an OFDM time-frequency resource provided in an embodiment of this application. As shown in Figure 1, in the OFDM time-frequency resource, in the time domain dimension, it is divided into multiple OFDM symbols, with each cell representing one OFDM symbol; in the frequency domain dimension, it is divided into multiple subcarriers, with each cell representing one subcarrier. A resource element (RE) refers to a time-frequency resource that occupies one OFDM symbol length in time and one subcarrier in frequency. That is, one square in Figure 1 represents one RE. On each RE, one modulated symbol (e.g., quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), such as 16QAM, etc.) can be transmitted.

[0082] In Figure 1, the numbers on the horizontal axis represent the index of a symbol in a time slot, and the numbers on the vertical axis represent the index of a subcarrier in a resource block (RB). Furthermore, the embodiments in this application are illustrated using a time slot containing 14 symbols as an example. In actual implementation, the number of symbols in a time slot may not be 14, for example, it may be 12. This situation also applies to this application.

[0083] From the perspective of each RE, the received signal can be viewed as the product of the transmitted signal and the channel coefficients. For example, the signal received on a single RE can be represented as:

[0084] y = hx + n

[0085] Where y represents the received signal, x is the signal transmitted on the RE, h is the response coefficient of the wireless channel, and n represents additive noise.

[0086] The channel coefficient h is a random variable that changes with transmission conditions. To recover the transmitted signal x from the received signal y, the channel coefficient h needs to be estimated, and its impact on the received signal needs to be offset. The process of estimating the channel response coefficient h is called channel estimation. To perform channel estimation, a known signal needs to be transmitted on some REs agreed upon by the transmit and receive parties. This signal is called the demodulation reference signal (DMRS). In 5G NR systems, the DMRS acts as a pilot signal, used for channel estimation, and the estimated channel information is used for data demodulation. Thus, the channel coefficient can be estimated using the received and transmitted signals.

[0087] With the introduction of multi-antenna technology into wireless communication systems, the transmitting end can transmit multiple streams of data on the same time-frequency resources, thereby increasing the system capacity. Multi-antenna technology refers to the use of multiple antennas at the transmitting end, receiving end, or both. In this case, multiple streams of data can be transmitted on the same time-frequency resources and all data can be recovered at the receiving end.

[0088] To perform channel estimation for a multi-antenna system, the transmitter needs to send DMRSs that are known to both the transmitter and receiver. It should be noted that in order to help the receiver estimate the channel response coefficients one by one, the transmitting antennas need to send DMRSs on different resources.

[0089] Figure 2 is a schematic diagram of DMRS orthogonalization through different antenna port time slots provided in an embodiment of this application. As shown in Figure 2, (a) in Figure 2 represents the signal transmitted by antenna 1. DMRS is transmitted on REs with subcarrier numbers 0, 2, 4, 6, 8, and 10 on the second and ninth OFDM symbols, while no data is transmitted on REs with subcarrier numbers 1, 3, 5, 7, 9, and 11. Data is transmitted on the other OFDM symbols.

[0090] Figure 2(b) shows the signal transmitted by antenna 2. On the second OFDM symbol and the ninth OFDM symbol, no data is transmitted on the REs with subcarrier numbers 0, 2, 4, 6, 8, and 10. DMRS is transmitted on the REs with subcarrier numbers 1, 3, 5, 7, 9, and 11, while data is transmitted on the other OFDM symbols.

[0091] As described above, in the signals transmitted by antenna 1 and antenna 2, the OFDM symbols corresponding to the DMRS are the same. In the signal transmitted by antenna 1, no data is transmitted at the RE position corresponding to the DMRS transmitted by antenna 2, and in the signal transmitted by antenna 2, no data is transmitted at the RE position corresponding to the DMRS transmitted by antenna 1. Thus, the DMRS transmitted by antenna 1 and antenna 2 do not interfere with each other, and are therefore said to be orthogonal. This allows the receiver to estimate the channel coefficients corresponding to the two antennas separately without causing interference.

[0092] From the existing NR DMRS configuration, in order to ensure the orthogonality of multiple ports, frequency-division multiplexing (FDM), time-division multiplexing (TDM), and code-division multiplexing (CDM) are used to make the channel estimation of multiple ports independent of each other, that is, to minimize interference.

[0093] FDM divides the carrier bandwidth into sub-bands or channels of different frequency bands. Each user can transmit their own signal simultaneously in different sub-channels. Therefore, for all users using FDM, they occupy different bandwidth resources at the same time.

[0094] TDM allows multiple users to share a channel on the same frequency band through time division. Each user is allocated one or more time slots to transmit information within a cycle, meaning each user occupies the same bandwidth at different times.

[0095] In contrast to CDM, each user can use the same frequency band to communicate at the same time. Since each user uses a specially selected different code pattern, there will be no interference between users. For example, orthogonal cover code (OCC) can be used to achieve code division multiplexing.

[0096] The time-frequency code domain resources used by DMRS are called DMRS antenna ports. Using different antenna ports can ensure the orthogonality of DMRS. For example, in Figure 2, antenna 1 and antenna 2 use different antenna ports to transmit DMRS.

[0097] Figure 3 illustrates a schematic diagram of single-symbol DMRS configuration 1 supported by the existing NR. As shown in Figure 3, for single-symbol type 1 DMRS, in the frequency domain, the DMRS sequence is mapped on one subcarrier every other subcarrier (or, the DMRS sequence is mapped on one of every two subcarriers), and in the time domain, the DMRS sequence is mapped on one symbol. Each port is mapped to the corresponding RE within the RB. In the frequency domain, frequency division can be used between CDM groups, i.e., frequency division is used between CDM groups consisting of ports 1000 and 1001, and between CDM groups consisting of ports 1002 and 1003. A code division configuration scheme within a CDM group (2 ports) is also used, i.e., code division is used between ports 1000 and 1001, and between ports 1002 and 1003. In the example of single-symbol DMRS configuration 1, multiplexing of up to 4 orthogonal DMRS ports can be achieved using a 2-frequency division and 2-code division (OCC length of 2) approach.

[0098] Figure 4 illustrates a schematic diagram of dual-symbol DMRS configuration 1 supported by the existing NR. As shown in Figure 4, for dual-symbol type 1 DMRS, in the frequency domain, the DMRS sequence is mapped on one subcarrier every other subcarrier (or, the DMRS sequence is mapped on one of every two subcarriers). In the time domain, the DMRS sequence is mapped on two symbols. Therefore, in the frequency domain, frequency division can be used between two CDM groups, namely, the CDM group consisting of ports 1000, 1001, 1004, and 1005, and the CDM group consisting of ports 1002, 1003, 1006, and 1007. The code division configuration scheme within a CDM group (4 ports) is as follows: code division is used between ports 1000, 1001, 1004, and 1007, and between ports 1002, 1003, 1006, and 1007. In the example of dual-symbol DMRS configuration 1, up to 8 orthogonal DMRS ports can be multiplexed using a 2-frequency division and 4-code division (OCC length of 4) approach.

[0099] It should be understood that, in the embodiments of this application, DMRS sequences mapped onto the same time and frequency resources belong to the same CDM group. That is, a CDM group indicates one or a group of physical resources (time and frequency resources), and different CDM groups correspond to different physical resources.

[0100] As shown in Figure 3, the DMRS sequence mapped to port 1000 (i.e., port number 1000) and the DMRS sequence mapped to port 1001 occupy the same time-frequency resources. This means that port 1000 (or DMRS port 1000) and port 1001 (or DMRS port 1001) belong to the same CDM group, specifically CDM group 0. Similarly, ports 1002 and 1003 belong to CDM group 1, indicating that this mapping method supports two CDM groups.

[0101] As shown in Figure 4, ports 1000, 1001, 1004, and 1005 belong to the same CDM group, namely CDM group 0. Ports 1002, 1003, 1006, and 1007 belong to the same CDM group, namely CDM group 1. That is, the mapping method supports two CDM groups.

[0102] Since different CDM groups correspond to different frequency domain resources, the DMRS ports included in different CDM groups can be orthogonally multiplexed using FDM. For example, orthogonal multiplexing of ports 1000 and 1002, or ports 1001 and 1003, or ports 1004 and 1006, or ports 1005 and 1007 can be achieved using FDM, etc.

[0103] Figure 5 illustrates a schematic diagram of the single-symbol DMRS configuration 2 supported by the existing NR. As shown in Figure 5, for single-symbol type 2 DMRS, in the frequency domain, the DMRS sequence is mapped on two consecutive subcarriers after every four subcarriers (or, the DMRS sequence is mapped on two consecutive subcarriers out of every six subcarriers). In the time domain, the DMRS sequence is mapped on one symbol. In the frequency domain, up to three orthogonal DMRS ports can be multiplexed using FDM, i.e., supporting three CDM groups. For example, as shown in Figure 5(a), ports 1000 and 1001 belong to the same CDM group, both CDM group 0; ports 1002 and 1003 belong to the same CDM group, both CDM group 1; and ports 1004 and 1005 belong to the same CDM group, both CDM group 2. That is, this mapping method supports three CDM groups. In the example of single-symbol DMRS configuration 2, up to 6 orthogonal DMRS ports can be multiplexed using a 3-frequency division and 2-code division (OCC length of 2) approach.

[0104] Figure 6 illustrates a schematic diagram of the dual-symbol DMRS configuration 2 supported by the existing NR. As shown in Figure 6, for dual-symbol type 2 DMRS, the DMRS sequence is mapped on two consecutive subcarriers after every four subcarrier intervals (or, on two consecutive subcarriers out of every six subcarriers). In the time domain, the DMRS sequence is mapped on two symbols. In the frequency domain, up to three orthogonal DMRS ports can also be multiplexed using FDM, supporting three CDM groups. For example, as shown in Figure 6, ports 1000, 1001, 1006, and 1007 belong to the same CDM group (CDM group 0); ports 1002, 1003, 1008, and 1009 belong to the same CDM group (CDM group 1); and ports 1004, 1005, 1010, and 1011 belong to the same CDM group (CDM group 2). That is, this mapping method supports three CDM groups. In the example of dual-symbol DMRS configuration 2, up to 12 orthogonal DMRS ports can be multiplexed using a 3-frequency division and 4-code division (OCC length of 4) approach.

[0105] Based on the above introduction of DMRS configuration method one and configuration method two, continuous placement of pilots in the frequency domain leads to severe inter-carrier interference (ICI) in high-speed scenarios, causing severe interference between pilot data. In DMRS configuration method two, when the four ports are code-divided, it is required that the channel frequency response remain constant within two DMRS symbol periods. However, in high-speed scenarios, the channel response changes rapidly, which leads to the failure to meet this assumption and ultimately results in severe destruction of the orthogonality of the four ports within the same OCC.

[0106] Figure 7 illustrates subcarrier interference in high-speed scenarios. As shown in Figure 7, ICI refers to inter-carrier interference in OFDM multi-carrier modulation. Generally, wireless channels experience two-dimensional fading, meaning the channel response distorts the signal in both time and frequency dimensions, resulting from multipath propagation and the Doppler effect. In typical scenarios, the user and base station are usually relatively stationary, meaning there is no relative movement speed (i.e., no Doppler effect). In this scenario, OFDM can address frequency-selective fading caused by multipath delay by adding a cyclic prefix. However, in scenarios where the user and base station are moving, i.e., when the Doppler effect exists, the subcarriers within an OFDM symbol will no longer be orthogonal, leading to inter-carrier interference.

[0107] In a multi-user multiple-input multiple-output system, if the channel conditions of the terminal device are poor or the terminal device moves at a high speed, the network device will configure an additional demodulation reference signal (DMRS) for the terminal device to improve the quality of the channel estimation of the terminal device.

[0108] Specifically, in each time slot, the first DMRS in terms of time is called the front load DMRS. In addition to the front load DMRS, after the network device and the terminal device establish a connection, if the channel conditions of the terminal device are poor or the terminal device moves at a high speed, the network device can configure additional DMRS for the terminal device to improve the quality of channel estimation by the terminal device.

[0109] Figure 8 shows a schematic diagram of an additional DMRS location provided in an embodiment of this application. As shown in Figure 8, the OFDM symbols configured by the network device for transmitting the additional DMRS can be 0 to 3, and these configurations are represented by "pos0" to "pos3". As shown in Figure 8(a), the configuration of OFDM symbols used for transmitting DMRS can be represented by "pos0", that is, there is only one pre-DMRS and 0 additional DMRS; as shown in Figure 8(b), the configuration of OFDM symbols used for transmitting DMRS can be represented by "pos1", that is, there is 1 pre-DMRS and 1 additional DMRS, which is located in the 9th OFDM symbol; as shown in Figure 8(c), the configuration of OFDM symbols used for transmitting DMRS can be represented by "pos2", that is, there is 1 pre-DMRS and 2 additional DMRS, which are located in the 6th and 9th OFDM symbols respectively; as shown in Figure 8(d), the configuration of OFDM symbols used for transmitting DMRS can be represented by "pos3", that is, there is 1 pre-DMRS and 3 additional DMRS, which are located in the 5th, 8th and 11th OFDM symbols respectively.

[0110] As can be seen from Figure 8, whether one additional DMRS is configured or multiple additional DMRS are configured, the frequency domain resources occupied by the additional DMRS are the same as those occupied by the front-end DMRS. When the terminal device is in a high-speed scenario, the accuracy of the terminal device when using DMRS for channel estimation is limited due to insufficient DMRS density.

[0111] In view of this, this application provides a communication method that increases the frequency domain resource density of the transmitted DMRS by using different frequency domain resources than the transmitted DMRS, thereby improving the accuracy of channel estimation by the terminal using DMRS signals in high-speed scenarios.

[0112] The communication method provided in this application will be described below. To facilitate understanding of the embodiments of this application, the communication system applicable to the embodiments of this application will be introduced first with reference to FIG4.

[0113] Figure 9 shows a schematic diagram of a communication system provided in an embodiment of this application. As shown in Figure 9, the communication system includes three communication devices, such as a network device 910, a terminal device 920, and a terminal device 930. The network device 910 can perform data communication with at least one of the terminal devices 920 and 930. For example, the network device 910 can transmit downlink signals to the terminal device 920 or the terminal device 930 using the communication method provided in this application. Of course, the terminal device 920 or the terminal device 930 can also transmit uplink signals to the network device 910 using the communication method provided in this application.

[0114] It should be understood that the communication system shown in Figure 9 may also include more network nodes, such as terminal devices or network devices. The network devices or terminal devices included in the communication system shown in Figure 9 can be the various forms of network devices or terminal devices described above. Embodiments of this application are not shown one by one in the figures.

[0115] Figure 10 shows a schematic diagram of another communication system provided in an embodiment of this application. As shown in Figure 10, the communication system includes two satellites, such as satellite 1010 and satellite 1020. Satellite 1010 and satellite 1020 are respectively composed of a communication module, a transceiver module, an acquisition, pointing, and tracking (APT) module, and an APT transmission and reception module. The communication module is responsible for the transmission of information between satellites and is the main body of the inter-satellite communication system; the transceiver module is used to send and receive wireless signals; the APT module is responsible for the acquisition, pointing, and tracking between satellites, wherein determining the direction of arrival of the incident signal is called acquisition, adjusting the transmitted wave to aim at the receiving direction is called pointing, and continuously adjusting the pointing and acquisition during the entire communication process is called tracking; the APT transmission and reception module is responsible for sending and receiving APT signals. Satellite 1010 can transmit information with satellite 1020 through the communication method provided in this application.

[0116] Figure 11 shows a schematic diagram of another example of a communication system provided in this application. As shown in Figure 11(a), the cellular communication system or wireless local area network communication system includes network device 1110, terminal device 1120, and terminal device 1130, that is, one network device can transmit signals to multiple terminals through the communication method provided in this application. As shown in Figure 11(b), the cellular communication system or wireless local area network communication system includes terminal device 1140, network device 1150, and network device 1160, that is, one terminal device can transmit signals to multiple network devices through the communication method provided in this application.

[0117] The communication method provided in this application will be described in detail below with reference to Figure 12. Figure 12 shows a schematic flowchart of a communication method 1200 provided in an embodiment of this application. This method 1200 can be applied in the scenarios shown in Figures 9, 10 or 11, and of course it can also be applied in other communication scenarios. This application embodiment does not limit it here.

[0118] It should also be understood that, in the embodiments of this application, the terminal device and network device are used as examples to illustrate the method. As an example and not a limitation, the executing entity of the method can also be a chip, chip system, or processor applied to the terminal device and network device. The following describes the communication method provided in the embodiments of this application using a network device as the sending end and a terminal device as the receiving end as an example.

[0119] As shown in Figure 12, method 1200 may include steps S1210 to S1240. The steps of method 1200 will be described in detail below with reference to Figure 12.

[0120] S1210. The network device sends a first indication information to the terminal. The first indication information is used to indicate the set of ports for transmitting additional DMRS. The frequency domain resources occupied by the additional DMRS transmitted by the ports in the set of additional DMRS are different from at least one of the frequency domain resources occupied by the pre-transmission DMRS.

[0121] In the embodiments of this application, at least one of the frequency domain resources occupied by the additional DMRS transmitted on the ports in the port set of the additional DMRS is different from the frequency domain resources occupied by the pre-transmission DMRS. In one possible implementation, both the frequency domain resources occupied by the additional DMRS and the frequency domain resources occupied by the pre-transmission DMRS are different.

[0122] In some embodiments, in order to make the frequency domain resources occupied by the additional DMRS transmitted on the ports in the port set of the additional DMRS different from at least one of the frequency domain resources occupied by the preceding DMRS, the network device may offset at least one of the frequency domain resources occupied by the additional DMRS based on the frequency domain resources occupied by the preceding DMRS.

[0123] Optionally, the offset in at least one frequency domain resource occupied by the additional DMRS is related to the frequency domain resource occupied by the transmission front DMRS, the subcarrier spacing of the front DMRS, and the number of configured additional DMRS symbols.

[0124] In some embodiments, the network device can uniformly offset the frequency domain resources occupied by the additional DMRS based on the frequency domain resources occupied by the preceding DMRS. That is, the frequency domain resources occupied by the time domain units of two adjacent DMRSs are offset by the same amount.

[0125] It should be understood that the time-domain units of two adjacent DMRSs include: two adjacent time-domain units of additional DMRSs, or the time-domain units of the preceding DMRS and the time-domain units of the additional DMRSs that are adjacent in the time domain.

[0126] In the embodiments of this application, the frequency domain resources occupied by the time domain units of two adjacent DMRS in the time domain are offset by the same amount, which can make the additional DMRS offset uniformly, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0127] In some embodiments, the offsets between the frequency domain resources occupied by the transmission pre-DMRS and the frequency domain resources occupied by the transmission first additional DMRS, the offsets between the frequency domain resources occupied by the transmission second additional DMRS and the frequency domain resources occupied by the transmission first additional DMRS, and the offsets between the frequency domain resources occupied by the transmission third additional DMRS and the frequency domain resources occupied by the transmission second additional DMRS are the same. The time domain resources occupied by the first additional DMRS are earlier than the time domain resources occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than the time domain resources occupied by the third additional DMRS.

[0128] In this embodiment of the application, when three additional DMRSs are configured, the offsets of the frequency domain resources occupied by the transmission front DMRS and the frequency domain resources occupied by the transmission first additional DMRS, the offsets of the frequency domain resources occupied by the transmission second additional DMRS and the frequency domain resources occupied by the transmission first additional DMRS, and the offsets of the frequency domain resources occupied by the transmission third additional DMRS and the frequency domain resources occupied by the transmission second additional DMRS are the same. This allows the first additional DMRS, the second additional DMRS, and the third additional DMRS to be offset evenly, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0129] Optionally, when two additional DMRSs are configured, the offset of the frequency domain resources occupied by the transmission front DMRS from the frequency domain resources occupied by the transmission first additional DMRS, and the offset of the frequency domain resources occupied by the transmission second additional DMRS from the frequency domain resources occupied by the transmission first additional DMRS are the same.

[0130] In some embodiments, the additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the l-th additional DMRS satisfies the following formula:

[0131] Where X is the maximum number of DMRS ports that can be used for DMRS transmission; n = 0, 1, ...; Δ is the number of subcarrier intervals; S is the length of the frequency domain OCC used by DMRS; k' = 0, 1, ..., S-1; r is the CDM group index where the transmission front-end DMRS is located; L is the total number of DMRS symbols; the resources occupied by the transmission front-end DMRS include the index l = l' of OFDM symbols, where l' = 0, 1, 2, ..., L-1.

[0132] In the embodiments of this application, the above formula can be used to achieve uniform offset of the first additional DMRS, the second additional DMRS, and the third additional DMRS, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0133] For example, Figure 13 shows a schematic diagram of an example DMRS transmission pattern. As shown in Figure 13, there are a total of 4 DMRS symbols in one time slot, where OFDM#1 is the pre-DMRS, OFDM#5 is the first additional DMRS, OFDM#8 is the second additional DMRS, and OFDM#11 is the third additional DMRS. OFDM#1 places the DMRS signal on the second subcarrier starting from the first subcarrier at an interval of Δ. However, for OFDM#5, the DMRS signal on the second subcarrier starts from the third subcarrier at an interval of Δ. OFDM#8 places the DMRS signal on the second subcarrier starting from the fifth subcarrier at an interval of Δ. OFDM#11 places the DMRS signal on the second subcarrier starting from the seventh subcarrier at an interval of Δ.

[0134] In other embodiments, the frequency domain resources occupied by the transmission pre-DMRS are adjacent to the frequency domain resources occupied by the transmission first additional DMRS, the frequency domain resources occupied by the transmission second additional DMRS are adjacent to the frequency domain resources occupied by the transmission third additional DMRS, the offset between the frequency domain resources occupied by the transmission first additional DMRS and the frequency domain resources occupied by the transmission second additional DMRS is related to the number of subcarrier intervals, the time domain resources occupied by the first additional DMRS are earlier than the frequency domain resources occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than the frequency domain resources occupied by the third additional DMRS.

[0135] In this embodiment, the frequency domain resources occupied by the transmission pre-DMRS are adjacent to the frequency domain resources occupied by the transmission first additional DMRS, and the frequency domain resources occupied by the transmission second additional DMRS are adjacent to the frequency domain resources occupied by the transmission third additional DMRS. This allows the REs to be connected in pairs, making them more robust against noise.

[0136] In some embodiments, the index k of the subcarrier in the additional DMRS port set that transmits the frequency domain resources occupied by the first additional DMRS satisfies the following formula (2):

[0137] The subcarrier index k of the frequency domain resources occupied by the transmission of the second additional DMRS satisfies the following formula (3):

[0138] The index k of the subcarriers that transmit the frequency domain resources occupied by the third additional DMRS satisfies the following formula (4):

[0139] In the embodiments of this application, based on the above formula, the frequency domain resources occupied by the transmission front DMRS and the frequency domain resources occupied by the transmission first additional DMRS are adjacent, and the frequency domain resources occupied by the transmission second additional DMRS and the frequency domain resources occupied by the transmission third additional DMRS are adjacent, which can make the REs connected together in pairs, making them more robust against noise.

[0140] For example, Figure 14 shows a schematic diagram of an example DMRS transmission pattern. As shown in Figure 14, there are a total of 4 DMRS symbols in one time slot, where OFDM#1 is the pre-DMRS, OFDM#5 is the first additional DMRS, OFDM#8 is the second additional DMRS, and OFDM#11 is the third additional DMRS. OFDM#1 places the DMRS signal on the second subcarrier starting from the first subcarrier at a interval of Δ. However, for OFDM#5, the DMRS signal on the second subcarrier starts from the second subcarrier at a interval of Δ. OFDM#8 places the DMRS signal on the second subcarrier starting from the fifth subcarrier at a interval of Δ. OFDM#11 places the DMRS signal on the second subcarrier starting from the sixth subcarrier at a interval of Δ.

[0141] As can be seen from Figure 14, the frequency domain resources on OFDM#5 occupied by the first additional DMRS are adjacent to the frequency domain resources on OFDM#1 occupied by the pre-transmission DMRS, and the frequency domain resources on OFDM#8 occupied by the second additional DMRS are adjacent to the frequency domain resources on OFDM#11 occupied by the third DMRS. However, the shift between the frequency domain resources on OFDM#5 occupied by the first additional DMRS and the frequency domain resources on OFDM#8 occupied by the second additional DMRS is Δ / 2.

[0142] In other embodiments, the additional DMRS is configured on two adjacent DMRS symbols, and the offset between the frequency domain resources occupied by the transmission front DMRS group and the frequency domain resources occupied by the transmission first additional DMRS group is related to the number of subcarrier intervals.

[0143] In this embodiment, the first additional DMRS group is offset based on the frequency domain resources occupied by the preceding DMRS group. The offset is related to the subcarrier spacing, so that the first additional DMRS group can be offset evenly, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0144] In some embodiments, the additional DMRS is configured on two adjacent DMRS symbols, and the frequency domain resources occupied by the transmission of the front DMRS port group are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS group.

[0145] In this embodiment, the first additional DMRS group is offset by 1 based on the frequency domain resources occupied by the pre-DMRS group, so that the frequency domain resources occupied by the first additional DMRS group and the frequency domain resources occupied by the pre-DMRS group are adjacent, which can connect the REs in pairs, making them more robust against noise.

[0146] In some embodiments, the index k of the subcarriers in the additional DMRS port set that transmit the frequency domain resources occupied by the first additional DMRS group satisfies the following formula (5):

[0147] in, Or A = 1.

[0148] In the embodiments of this application, the above formula can be used to make the frequency domain resources occupied by the first additional DMRS group uniformly offset from the frequency domain resources occupied by the preceding DMRS group, or the above formula can be used to make the frequency domain resources occupied by the first additional DMRS group and the frequency domain resources occupied by the preceding DMRS group adjacent.

[0149] For example, Figure 15 shows a schematic diagram of an example DMRS transmission pattern. As shown in Figure 15, there are a total of 4 DMRS symbols in one time slot, where OFDM#0 and OFDM#1 are both pre-emerging DMRS, and OFDM#8 and OFDM#9 are both supplementary DMRS. OFDM#0 and OFDM#1 can also be referred to as the pre-emerging DMRS group, and OFDM#8 and OFDM#9 can also be referred to as the supplementary DMRS group. OFDM#0 and OFDM#1 place the DMRS signal on the second subcarrier at an interval of Δ starting from the first subcarrier. However, for OFDM#8 and OFDM#9, the DMRS signal on the second subcarrier is placed at an interval of Δ starting from the fifth subcarrier.

[0150] In some other embodiments, the frequency domain resources occupied by the transmission of the pre-transmission DMRS are the same as those occupied by the transmission of the second additional DMRS, the offset between the frequency domain resources occupied by the transmission of the second additional DMRS and those occupied by the transmission of the first DMRS is related to the number of subcarrier intervals, the frequency domain resources occupied by the transmission of the third additional DMRS are the same as those occupied by the transmission of the first additional DMRS, the time domain resources occupied by the first additional DMRS are earlier than those occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than those occupied by the third additional DMRS.

[0151] In this embodiment, the frequency domain resources occupied by the first additional DMRS and the third additional DMRS are offset based on the frequency domain resources occupied by the preceding DMRS, while the frequency domain resources occupied by the second additional DMRS remain unchanged. This improves the channel estimation accuracy while reducing signaling overhead.

[0152] In some embodiments, the additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the 2Nth additional DMRS satisfies the following formula (6), where N is greater than or equal to 1 and N is an integer:

[0153] The index k of the subcarrier that transmits the frequency domain resources occupied by the 2N-1th additional DMRS satisfies the following formula (7):

[0154] In the embodiments of this application, the above formula can be used to offset the frequency domain resources occupied by the first additional DMRS and the third additional DMRS based on the frequency domain resources occupied by the preceding DMRS, while the frequency domain resources occupied by the second additional DMRS remain unchanged, thereby improving the channel estimation accuracy while reducing signaling overhead.

[0155] It should be understood that in the existing protocol, OFDM#5, OFDM#8, and OFDM#11 are three additional DMRS. In the embodiments of this application, the frequency domain resources occupied by transmitting the second additional DMRS are the same as those occupied by transmitting the first additional DMRS, and the frequency domain resources occupied by transmitting the first additional DMRS are the same as those occupied by transmitting the third DMRS. Furthermore, they are all offset by Δ / 2 relative to the frequency domain resources occupied by the first additional DMRS.

[0156] Of course, if the communication protocol supports more additional DMRS, then odd DMRS will be offset and even DMRS will not be offset, or odd DMRS will not be offset and even DMRS will be offset. This application does not specifically limit this.

[0157] For example, Figure 16 shows a schematic diagram of another example of DMRS transmission. As shown in Figure 16, there are a total of 4 DMRS symbols in one time slot, where OFDM#2 is the pre-installed DMRS, and OFDM#5, OFDM#8, and OFDM#11 are additional DMRS. OFDM#1 places the DMRS signal on the second subcarrier starting from the first subcarrier at an interval of Δ. OFDM#8 also places the DMRS signal on the second subcarrier starting from the first subcarrier at an interval of Δ. However, for OFDM#5, the DMRS signal on the second subcarrier starts from the fifth subcarrier at an interval of Δ. OFDM#11 also places the DMRS signal on the second subcarrier starting from the fifth subcarrier at an interval of Δ.

[0158] S1220: The terminal determines the time and frequency resources for receiving the additional DMRS based on the first instruction information.

[0159] Accordingly, the terminal receives the first indication information and determines the time and frequency resources for receiving the additional DMRS based on the port set for transmitting the additional DMRS indicated by the first indication information.

[0160] For example, as shown in FIG13, the port set indicated by the first indication information includes port 1000 and port 1001. The time-frequency resources for the terminal device to receive the first additional DMRS are the third subcarrier and the eleventh subcarrier in the OFDM#5 frequency domain in the time domain; the time-frequency resources for receiving the second additional DMRS are the fifth subcarrier and the thirteenth subcarrier in the OFDM#8 frequency domain in the time domain; and the time-frequency resources for receiving the third additional DMRS are the seventh subcarrier and the fifteenth subcarrier in the OFDM#11 frequency domain in the time domain.

[0161] For example, as shown in Figure 14, the port set indicated by the first indication information includes port 1000 and port 1001. The time-frequency resources for the terminal device to receive the first additional DMRS are the second and tenth subcarriers in the OFDM#5 frequency domain; the time-frequency resources for receiving the second additional DMRS are the fifth and thirteenth subcarriers in the OFDM#8 frequency domain; and the time-frequency resources for receiving the third additional DMRS are the sixth and fourteenth subcarriers in the OFDM#11 frequency domain.

[0162] For example, as shown in Figure 15, the port set indicated by the first indication information includes port 1000, port 1001, port 1002 and port 1003. The time-frequency resources of the terminal device receiving the first additional DMRS group are OFDM#8 and OFDM#11 in the time domain and the fifth subcarrier and the thirteenth subcarrier in the frequency domain.

[0163] For example, as shown in Figure 16, the port set indicated by the first indication information includes port 1000. The time-frequency resources for the terminal device to receive the first additional DMRS are OFDM#5 in the time domain and the first and ninth subcarriers in the frequency domain; the time-frequency resources for receiving the second additional DMRS are OFDM#8 in the time domain and the fourth and twelfth subcarriers in the frequency domain; and the time-frequency resources for receiving the third additional DMRS are OFDM#11 in the time domain and the first and ninth subcarriers in the frequency domain.

[0164] S1230. The network device sends additional DMRS through a port in the additional DMRS port set.

[0165] S1240. The terminal receives additional DMRS on the time-frequency resources of each DMRS port to perform channel estimation.

[0166] In some embodiments, the terminal receives additional DMRS based on determined time-frequency resources for receiving additional DMRS. Since the frequency domain resources occupied by the additional DMRS are different from those occupied by the preceding DMRS, the density of the additional DMRS received by the terminal is greater, and the accuracy of channel estimation is better when the received additional DMRS is finally used.

[0167] For example, please refer to Figure 13. The right side of Figure 13 shows the equivalent diagrams of OFDM#1, OFDM#5, OFDM8 and OFDM#11. It can be seen from the figure that the DMRS allocated in the time domain is more dense after the equivalent, so the terminal has better accuracy when using the denser DMRS for channel estimation.

[0168] For example, as shown in Figure 14, the right side of Figure 14 displays the DMRS symbol resulting from the merging of OFDM#1 and OFDM#5, and the DMRS symbol resulting from the merging of OFDM8 and OFDM#11. It can be seen from the figure that in the DMRS symbol resulting from the merging of OFDM#1 and OFDM#5, every pair of REs is adjacent; similarly, in the DMRS symbol resulting from the merging of OFDM8 and OFDM#11, every pair of REs is adjacent, making it more robust against noise.

[0169] The method provided in this application increases the density of transmitted DMRS by using a port in the port set of the additional DMRS that occupies at least one of the frequency domain resources occupied by the port of the additional DMRS that occupies the port of the transmission preceding DMRS. This allows the terminal to improve the channel estimation accuracy when using the received DMRS.

[0170] Figure 17 illustrates the block error rate (BLER) performance of a 4-port system. As shown in Figure 17, the horizontal axis represents the signal-to-noise ratio (SNR), and the vertical axis represents BLER. Case 4-2: proposed DMRS + changed SCS + enhancement. This curve is represented by a gray line and circular markers. It shows the BLER performance when the DMRS (demodulation reference signal) is modified, the SCS (subcarrier spacing) is changed, and enhancement measures are applied. Case 0 (baseline / REF): NR DMRS pattern 1. This curve is represented by a black line and diamond markers. It shows the BLER performance in the baseline or reference case, using NR DMRS pattern 1. As can be seen from Figure 17, the modification proposed in Case 4-2 results in a lower BLER than the baseline Case 0 across the entire SNR range shown. It should be understood that the curve shown in Case 4-2 represents the solution provided in the embodiments of this application, demonstrating that the error rate performance of the system is improved by the solution provided in this application.

[0171] The foregoing has detailed examples of the communication methods provided in this application. It is understood that terminal devices and network devices, in order to achieve the above functions, include corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0172] The communication device provided in this application will be described below.

[0173] For example, FIG18 shows a schematic block diagram of a communication device 1800 provided in an embodiment of the present application. The communication device 1800 may correspond to the network device or terminal device described in the various embodiments of the method 1200 above, or it may be applied in a chip or component of a network device or terminal device. Furthermore, each module or unit in the communication device 1800 is used to execute the various actions or processing procedures performed by the network device or terminal device described in the various embodiments of the method 1200 above.

[0174] As shown in Figure 18, the communication device 1800 includes a processing unit 1810 and a transceiver unit 1820. The transceiver unit 1820 is used to perform specific signal transmission and reception under the drive of the processing unit 1810.

[0175] In some embodiments:

[0176] The transceiver unit 1820 sends first indication information to the terminal. The first indication information is used to indicate the set of ports for transmitting additional DMRS. The frequency domain resources occupied by the additional DMRS transmitted by the ports in the set of additional DMRS are different from at least one of the frequency domain resources occupied by the transmission of the pre-DMRS.

[0177] The transceiver unit 1820 is also configured to send the additional DMRS to the terminal via a port in the port set of the additional DMRS.

[0178] In other embodiments:

[0179] Transceiver unit 1820: is used to receive first indication information, the first indication information being used to indicate a set of ports for transmitting additional DMRS, wherein at least one of the frequency domain resources occupied by the additional DMRS transmitted by the ports in the set of additional DMRS is different from the frequency domain resources occupied by the preceding DMRS.

[0180] The transceiver unit 1820 is further configured to receive the additional DMRS on the time-frequency resources corresponding to the additional DMRS port in the port set of the additional DMRS, according to the first indication information.

[0181] Optionally, the frequency domain resources occupied by the transmission of the additional DMRS in the ports of the transmission additional DMRS port set are related to the frequency domain resources occupied by the transmission of the pre-DMRS, the subcarrier spacing of the pre-DMRS, and the number of the configured additional DMRS symbols.

[0182] Optionally, the time-domain units of two adjacent DMRS occupy the same offset of frequency-domain resources. The time-domain units of two adjacent DMRS include: two adjacent additional DMRS time-domain units, or the time-domain units of the preceding DMRS and the additional DMRS that are adjacent in the time domain.

[0183] Optionally, the offsets between the frequency domain resources occupied by the pre-DMRS and the frequency domain resources occupied by the first additional DMRS, the offsets between the frequency domain resources occupied by the second additional DMRS and the frequency domain resources occupied by the first additional DMRS, and the offsets between the frequency domain resources occupied by the third additional DMRS and the frequency domain resources occupied by the second additional DMRS are the same. The time domain resources occupied by the first additional DMRS are earlier than the time domain resources occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than the time domain resources occupied by the third additional DMRS.

[0184] Optionally, the additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the l-th additional DMRS satisfies the following formula:

[0185] Where X is the maximum number of DMRS ports that can be used for DMRS transmission; n = 0, 1, ...; Δ is the number of subcarrier intervals; S is the length of the frequency domain OCC used by the DMRS; k' = 0, 1, ..., S-1; r is the CDM group index where the first DMRS port is located; L is the total number of DMRS symbols; and the index l = l' of the OFDM symbols included in the resources occupied by the DMRS transmitted by the first DMRS port is where l' = 0, 1, 2, ..., L-1.

[0186] Optionally, the frequency domain resources occupied by the transmission of the pre-DMRS are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS, and the frequency domain resources occupied by the transmission of the second additional DMRS are adjacent to the frequency domain resources occupied by the transmission of the third additional DMRS. The offset between the frequency domain resources occupied by the transmission of the first additional DMRS and the frequency domain resources occupied by the transmission of the second additional DMRS is related to the number of subcarrier intervals. The time domain resources occupied by the first additional DMRS are earlier than the frequency domain resources occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than the frequency domain resources occupied by the third additional DMRS.

[0187] Optionally, the index k of the subcarrier in the additional DMRS port set that transmits the frequency domain resources occupied by the first additional DMRS satisfies the following formula:

[0188] The subcarrier index k for transmitting the frequency domain resources occupied by the second additional DMRS satisfies the following formula:

[0189] The index k of the subcarriers transmitting the frequency domain resources occupied by the third additional DMRS satisfies the following formula:

[0190] Optionally, the additional DMRS is configured on two adjacent DMRS symbols, and the offset between the frequency domain resources occupied by the transmission of the preceding DMRS group and the frequency domain resources occupied by the transmission of the first additional DMRS group is related to the number of subcarrier intervals.

[0191] Optionally, the additional DMRS is configured on two adjacent DMRS symbols, and the frequency domain resources occupied by the transmission of the front-end DMRS port group are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS group.

[0192] Optionally, the index k of the subcarriers in the additional DMRS port set that transmit the frequency domain resources occupied by the first additional DMRS group satisfies the following formula:

[0193] in, Or A = 1.

[0194] Optionally, the frequency domain resources occupied by the transmission of the first DMRS are the same as those occupied by the transmission of the second additional DMRS. The offset between the frequency domain resources occupied by the transmission of the second additional DMRS and those occupied by the transmission of the first DMRS is related to the number of subcarrier intervals. The frequency domain resources occupied by the transmission of the third additional DMRS are the same as those occupied by the transmission of the first additional DMRS. The time domain resources occupied by the first additional DMRS are earlier than those occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than those occupied by the third additional DMRS.

[0195] Optionally, the additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the 2Nth additional DMRS satisfies the following formula, where N is greater than or equal to 1 and N is an integer:

[0196] The index k of the subcarrier that transmits the frequency domain resources occupied by the (2N-1)th additional DMRS satisfies the following formula:

[0197] It should be understood that the specific process by which each unit in the communication device 1800 performs the above-described corresponding steps is described in the preceding text in conjunction with method 1200 and the relevant embodiments in Figure 12 regarding the network device or terminal device. For example, the transceiver unit 1820 can perform the receiving and sending steps involved in the above method embodiments, while the processing unit 1810 can perform steps other than receiving and sending. Various specific processes are as described in the method embodiments. For the sake of brevity, they will not be elaborated here.

[0198] It should be understood that the transceiver unit 1820 may be a transceiver, an input / output interface, or an interface circuit. The storage unit may be a memory. The processing unit 1810 may be implemented by a processor. Figure 19 shows a schematic block diagram of another example of a communication device 1900 provided in an embodiment of this application. As shown in Figure 19, the communication device 1900 may include a processor 1910, a memory 1920, and a transceiver 1930.

[0199] The communication device 1800 shown in Figure 18 or the communication device 1900 shown in Figure 19 can implement the steps performed by the network device or terminal device in the various embodiments of the aforementioned method 1200. Similar descriptions can be found in the descriptions of the corresponding methods described above. To avoid repetition, they will not be repeated here.

[0200] It should also be understood that the communication device 1800 shown in Figure 18 or the communication device 1900 shown in Figure 19 can be a network device or a terminal device.

[0201] It should also be understood that the division of units in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, all units in the device can be implemented entirely through software calls from processing elements; all units can be implemented entirely in hardware; or some units can be implemented through software calls from processing elements, while others are implemented in hardware. For example, each unit can be a separate processing element, or it can be integrated into a chip within the device. Alternatively, it can be stored as a program in memory, and its function can be called and executed by a processing element within the device. Here, the processing element can also be called a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above units can be implemented through integrated logic circuits in the processor element or through software calls from processing elements.

[0202] In one example, a unit in any of the above devices can be one or more integrated circuits configured to implement the methods described above, such as one or more application-specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these forms of integrated circuits. As another example, when a unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor capable of calling programs. Furthermore, these units can be integrated together to implement a system-on-a-chip (SOC).

[0203] Figure 20 is a schematic diagram of the structure of a network device 2000 provided in an embodiment of this application, which can be used to implement the functions of the network device in the above method. The network device 2000 includes one or more radio frequency (RF) units, such as a remote radio unit (RRU) 2001 and one or more baseband units (BBU) 2002. The RRU 2001 can be called a transceiver unit, transceiver, transceiver circuit, or transceiver, etc., and may include at least one antenna 2011 and an RF unit 20012. The RRU 2001 is mainly used for transmitting and receiving RF signals and converting RF signals to baseband signals, for example, for sending signaling messages as described in the above embodiment to a terminal device. The BBU 2002 is mainly used for baseband processing and controlling the base station. The RRU 2001 and BBU 2002 can be physically arranged together or physically separated, i.e., a distributed base station.

[0204] The BBU2002 serves as the control center of the base station, also known as the processing unit. It primarily performs baseband processing functions such as channel coding, multiplexing, modulation, and spread spectrum. For example, the BBU (processing unit) 2002 can control the base station to execute the network device operation procedures described in the above method embodiments.

[0205] In one example, the BBU2002 can be composed of one or more single boards. Multiple single boards can collectively support a single access standard wireless access network (such as an LTE system or a 5G system), or they can each support wireless access networks with different access standards. The BBU2002 also includes a memory 20021 and a processor 20022. The memory 20021 is used to store necessary instructions and data. For example, the memory 20021 stores the codebook as described in the above embodiments. The processor 20022 is used to control the base station to perform necessary actions, such as controlling the base station to execute the operation procedures related to the network device in the above method embodiments. The memory 20021 and processor 20022 can serve one or more single boards. That is, each single board can have its own memory and processor, or multiple single boards can share the same memory and processor. Furthermore, each single board can also have necessary circuitry.

[0206] In one possible implementation, with the development of system-on-chip (SoC) technology, all or part of the functions of parts 2002 and 2001 can be implemented by SoC technology, for example, by a base station function chip. This base station function chip integrates a processor, memory, antenna interface, and other devices. The program for base station-related functions is stored in the memory, and the processor executes the program to implement the relevant functions of the base station. Optionally, the base station function chip can also read external memory to implement the relevant functions of the base station.

[0207] It should also be understood that the division of units in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, all units in the device can be implemented entirely through software calls from processing elements; all units can be implemented entirely in hardware; or some units can be implemented through software calls from processing elements, while others are implemented in hardware. For example, each unit can be a separate processing element, or it can be integrated into a chip within the device. Alternatively, it can be stored as a program in memory, and its function can be called and executed by a processing element within the device. Here, the processing element can also be called a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above units can be implemented through integrated logic circuits in the processor element or through software calls from processing elements. In one example, a unit in any of the above devices can be one or more integrated circuits configured to implement the methods described above, such as one or more application-specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these forms of integrated circuits. As another example, when a unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor capable of calling programs. Furthermore, these units can be integrated together to implement a system-on-a-chip (SOC).

[0208] This application also provides a chip system, as shown in FIG21, which includes at least one processor 2110 and at least one interface circuit 2120. The processor 2110 and the interface circuit 2120 can be interconnected via lines. For example, the interface circuit 2120 can be used to receive signals from other devices (e.g., the memory of network device 2100). As another example, the interface circuit 2120 can be used to send signals to other devices (e.g., processor 2010). Exemplarily, the interface circuit 2120 can read instructions stored in memory and send the instructions to the processor 2110. When the instructions are executed by the processor 2110, the terminal device can perform the various steps executed by the terminal device in the above embodiments. Of course, the chip system may also include other discrete devices, which are not specifically limited in this application.

[0209] This application also provides a computer-readable storage medium for storing computer program code, the computer program including instructions for executing any of the communication methods provided in the embodiments of this application. The readable medium may be a read-only memory (ROM) or a random access memory (RAM), and this application does not impose any limitations on this.

[0210] This application also provides a computer program product including instructions that, when executed, cause a network device or a terminal device to perform operations corresponding to those described in the above methods.

[0211] This application also provides a chip located in a communication device. The chip includes a processing unit and a communication unit. The processing unit may be, for example, a processor, and the communication unit may be, for example, an input / output interface, pins, or circuitry. The processing unit can execute computer instructions to cause the communication device to perform any of the communication methods provided in the embodiments of this application.

[0212] Optionally, the computer instructions are stored in a storage unit.

[0213] Optionally, the storage unit can be an internal storage unit within the chip, such as a register or cache. Alternatively, it can be an external storage unit located within the terminal, such as a ROM or other types of static storage devices capable of storing static information and instructions, such as random access RAM. The processor mentioned above can be a CPU, microprocessor, ASIC, or one or more integrated circuits used to control the execution of programs for the aforementioned communication methods. The processing unit and the storage unit can be decoupled and disposed on different physical devices, connected via wired or wireless means to implement their respective functions, thereby supporting the system chip in implementing the various functions described in the above embodiments. Alternatively, the processing unit and the memory can also be coupled to the same device.

[0214] In this embodiment, the terminal device, computer-readable storage medium, computer program product or chip are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0215] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be RAM, which is used as an external cache. RAM has various types, such as 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 rambus RAM (DR RAM).

[0216] In this application, various objects such as messages / information / devices / network elements / systems / apparatus / actions / operations / processes / concepts may be named. It is understood that these specific names do not constitute a limitation on the relevant objects. The names may be changed depending on the scenario, context, or usage habits. The understanding of the technical meaning of the technical terms in this application should be mainly determined from their functions and technical effects embodied / performed in the technical solution.

[0217] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0218] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0219] The methods in the embodiments of this application can be implemented, in whole or in part, by software, hardware, firmware, or any combination thereof. When implemented in software, they can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed, in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server integrating one or more available media.

[0220] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0221] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0222] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0223] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0224] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned readable storage medium includes various media capable of storing program code, such as USB flash drives, external hard drives, ROM, RAM, magnetic disks, or optical disks.

Claims

1. A communication method, characterized in that, The method includes: Send a first indication message to the terminal. The first indication message is used to indicate the set of ports for transmitting additional DMRS. The frequency domain resources occupied by the additional DMRS transmitted by the ports in the set of ports for additional DMRS are different from at least one of the frequency domain resources occupied by the transmission of the pre-DMRS. The additional DMRS is sent to the terminal through a port in the port set of the additional DMRS.

2. A communication method, characterized in that, The method includes: Receive first indication information, the first indication information being used to indicate a set of ports transmitting additional DMRS, wherein the frequency domain resources occupied by the additional DMRS transmitted by the ports in the set of additional DMRS are different from at least one of the frequency domain resources occupied by the transmission of the preceding DMRS. According to the first indication information, the additional DMRS is received on the time-frequency resources corresponding to the additional DMRS port in the additional DMRS port set.

3. The method according to claim 1 or 2, characterized in that, The frequency domain resources occupied by the additional DMRS in the ports of the set of additional DMRS ports are related to the frequency domain resources occupied by the preceding DMRS, the subcarrier spacing of the preceding DMRS, and the number of additional DMRS symbols configured.

4. The method according to any one of claims 1-3, characterized in that, The time-domain units of two adjacent DMRS occupy the same offset of frequency domain resources. The time-domain units of two adjacent DMRS include: two adjacent additional DMRS time-domain units, or the time-domain units of the preceding DMRS and the additional DMRS that are adjacent in the time domain.

5. The method according to claim 4, characterized in that, The offsets between the frequency domain resources occupied by the pre-DMRS and those occupied by the first additional DMRS, the offsets between the frequency domain resources occupied by the second additional DMRS and those occupied by the first additional DMRS, and the offsets between the frequency domain resources occupied by the third additional DMRS and those occupied by the second additional DMRS are the same. The time domain resources occupied by the first additional DMRS are earlier than those occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than those occupied by the third additional DMRS.

6. The method according to claim 5, characterized in that, The additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the l-th additional DMRS satisfies the following formula: Where X is the maximum number of DMRS ports that can be used for DMRS transmission; n = 0, 1, ...; Δ is the number of subcarrier intervals; S is the length of the frequency domain OCC used by the DMRS; k' = 0, 1, ..., S-1; r is the CDM group index where the transmission front-end DMRS is located; L is the total number of DMRS symbols; the resources occupied by the transmission front-end DMRS include the index l = l' of OFDM symbols, where l' = 0, 1, 2, ..., L-1.

7. The method according to any one of claims 1-3, characterized in that, The frequency domain resources occupied by the transmission of the pre-DMRS are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS, and the frequency domain resources occupied by the transmission of the second additional DMRS are adjacent to the frequency domain resources occupied by the transmission of the third additional DMRS. The offset between the frequency domain resources occupied by the first additional DMRS and the frequency domain resources occupied by the second additional DMRS is related to the number of subcarrier intervals. The time domain resources occupied by the first additional DMRS are earlier than the frequency domain resources occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than the frequency domain resources occupied by the third additional DMRS.

8. The method according to claim 7, characterized in that, The index k of the subcarrier in the additional DMRS port set that transmits the frequency domain resources occupied by the first additional DMRS satisfies the following formula: The subcarrier index k for transmitting the frequency domain resources occupied by the second additional DMRS satisfies the following formula: The index k of the subcarriers transmitting the frequency domain resources occupied by the third additional DMRS satisfies the following formula:

9. The method according to any one of claims 1-3, characterized in that, The additional DMRS is configured on two adjacent DMRS symbols, and the offset between the frequency domain resources occupied by the transmission of the preceding DMRS group and the frequency domain resources occupied by the transmission of the first additional DMRS group is related to the number of subcarrier intervals.

10. The method according to any one of claims 1-3, characterized in that, The additional DMRS is configured on two adjacent DMRS symbols, and the frequency domain resources occupied by the transmission of the front-end DMRS port group are adjacent to the frequency domain resources occupied by the transmission of the first additional DMRS group.

11. The method according to claim 9 or 10, characterized in that, The index k of the subcarriers in the additional DMRS port set that transmit the frequency domain resources occupied by the first additional DMRS group satisfies the following formula: in, Or A = 1.

12. The method according to any one of claims 1-3, characterized in that, The frequency domain resources occupied by the transmission of the first DMRS are the same as those occupied by the transmission of the second additional DMRS. The offset between the frequency domain resources occupied by the transmission of the second additional DMRS and those occupied by the transmission of the first DMRS is related to the number of subcarrier intervals. The frequency domain resources occupied by the transmission of the third additional DMRS are the same as those occupied by the transmission of the first additional DMRS. The time domain resources occupied by the first additional DMRS are earlier than those occupied by the second additional DMRS, and the time domain resources occupied by the second additional DMRS are earlier than those occupied by the third additional DMRS.

13. The method according to claim 12, characterized in that, The additional DMRS is configured on a symbol, and the index k of the subcarrier in the set of additional DMRS ports that transmits the frequency domain resources occupied by the 2Nth additional DMRS satisfies the following formula, where N is greater than or equal to 1 and N is an integer: The index k of the subcarrier that transmits the frequency domain resources occupied by the (2N-1)th additional DMRS satisfies the following formula:

14. A communication device, characterized in that, include: A module or unit for performing the method as described in any one of claims 1 to 13.

15. A communication device, characterized in that, include: A processor and a memory, the processor being coupled to the memory, the memory being used to store a computer program, which, when executed by the processor, causes the apparatus to perform the method as described in any one of claims 1 to 13.

16. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when run on a computer, causes the computer to perform the method as described in any one of claims 1 to 13.

17. A computer program product, characterized in that, include: A computer program that, when run on a computer, causes the computer to perform the method as described in any one of claims 1 to 13.

18. A communication system, characterized in that, The device includes a network device and a terminal, the network device being configured to perform the method as described in any one of claims 1 to 3 to 11, and the terminal being configured to perform the method as described in any one of claims 2 to 3 to 11.

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