METHOD AND APPARATUS FOR DATA TRANSMISSION

Abstract

The present invention relates to a method of data transmission and an apparatus. The method includes sending, by a first device, the first indication information, wherein the first indication information is used to indicate a time and frequency resource of a first reference signal, and the first reference signal is used to perform channel estimation on the retransmitted data from the first data; and sending, by the first device, the retransmitted data. When the time and frequency resource occupied by the reference signal, and indicated by the first indication information, is less than a time and frequency resource occupied by a reference signal used for the initial transmission of the first data, reference signal overheads can be reduced, and the flexibility of configuring reference signal resources and the efficiency of data transmission are improved.

Description

1 / 39 “METHOD AND APPARATUS FOR DATA TRANSMISSION”

[0001] This application claims priority of the Patent Application Chinese Patent Application No. 201710010473.3, filed with the Chinese Patent Office on January 6, 2017, and entitled DATA TRANSMISSION METHOD AND APPARATUS, and Chinese Patent Application No. 201710459563.0, filed with the Chinese Patent Office on June 16, 2017, and entitled DATA TRANSMISSION METHOD AND APPARATUS, which are incorporated herein by reference in their entirety. Technical Field

[0002] The present invention relates to the field of communications, and in particular to a method of data transmission and an apparatus. Background

[0003] In a wireless communications system, a reference signal (Reference Signal, RS), also referred to as a pilot signal, is a known signal sent by a sending device to a receiving device on a known resource. The receiving device can obtain channel-related information based on the received reference signal to complete channel estimation or channel measurement. A result of the channel measurement can be used for resource scheduling and link adaptation, and a result of the channel estimation can be used by the receiving device to demodulate the data.

[0004] An ultra-reliable, low-latency communications service (Ultra-Reliable Low-Latency Communications, URLLC) is an important service in a future mobile communications system. The URLLC service typically requires very high reliability (e.g., 99.999%) and very low latency (e.g., 1 ms). A hybrid auto-repeat request technology (hybrid auto-repeat request, HARQ) can be used. Petition 870250050106, dated 06 / 16 / 2025, page 12 / 103 2 / 39 to improve the reliability of the URLLC service. A URLLC packet may need to be transmitted multiple times. The interval between an initial transmission and a final transmission typically does not exceed the 1 ms latency required by the URLLC service, as illustrated in Figure 1.

[0005] A current downlink reference signal design scheme in LTE cannot adapt to a new service, such as URLLC, and a new application situation where data transmission efficiency is relatively low. Summary

[0006] This application provides a method and apparatus for data transmission, to improve the efficiency of data transmission. To solve the above technical problem, this application describes the following technical solutions.

[0007] According to a first aspect, an embodiment of this request provides a method of data transmission, and the method includes sending, by a first device, the first indication information, where the first indication information is used to indicate a time frequency feature of a first reference signal, and the first reference signal is used to perform channel estimation on the retransmitted data from the first data; and sending, by the first device, the retransmitted data.

[0008] According to the method provided in this respect, the first device sends the first indication information, the first indication information is used to indicate a time and frequency resource of a reference signal used to transmit the first data a second time or subsequently, and this time and frequency resource may be the same as or different from a time and frequency resource of a reference signal used for the initial transmission of the first data. When the time and Petition 870250050106, dated 06 / 16 / 2025, p. 13 / 103 3 / 39 frequency indicated by the first indication information is lower than the time and frequency resource occupied by a reference signal used for the initial transmission of the first data, the overheads of the reference signal can be reduced, and the flexibility of reference signal resource configuration and data transmission efficiency are improved.

[0009] Additionally, the time interval between a transmission In the subsequent N and the initial transmission, the channel changes very slightly. Therefore, a channel estimation result performed by a second device serving as a receiving end is not affected when the time and frequency resources of the reference signals are more sparse than those of the initial transmission, thus further ensuring channel estimation accuracy while reducing reference signal overhead.

[0010] With reference to the first aspect, in a first implementation of the first aspect, the first indication information includes information used to indicate a time and frequency location of the first reference signal.

[0011] With reference to the first implementation of the first aspect, in a second implementation of the first aspect, the time and frequency location information includes at least one of a frequency domain spacing, a frequency domain offset, a time domain spacing, and a time domain offset. In this aspect, a time and frequency resource location of a reference signal used in subsequent transmission may be configured differently from a location for the initial transmission. In other words, the reference signal has a frequency offset, so that in transmission N, a frequency domain location of the first signal of Petition 870250050106, dated 06 / 16 / 2025, page 14 / 103 4 / 39 reference and a frequency domain location of a second reference signal are staggered, thus improving the accuracy of a channel estimation result from a receiving device.

[0012] With reference to the first aspect, in a third implementation of the first aspect, the first indication information is additionally used to indicate that the first device does not send the first reference signal, in other words, the reference signal does not occupy any time and frequency resources, and overheads are minimal.

[0013] With reference to any of the first to third implementations of the first aspect, in a fourth implementation of the first aspect, the method additionally includes sending the second indication information, where the second indication information is used to indicate a time and frequency resource of a second reference signal, and the second reference signal is used to perform channel estimation in an initial transmission of the first data. The first indication information and the second indication information may be sent simultaneously or may be sent sequentially. For example, the second indication information is sent first, and then the first indication information is sent.

[0014] With reference to the fourth implementation of the first aspect, in a fifth implementation of the first aspect, the second indication information includes a time and frequency location of the second reference signal.

[0015] With reference to the fifth implementation of the first aspect, in a sixth implementation of the first aspect, the time and frequency location information includes at least one of a frequency domain spacing, a domain deviation of Petition 870250050106, dated 06 / 16 / 2025, page 15 / 103 5 / 39 frequency, a time-domain spacing, and a time-domain offset.

[0016] With reference to any of the fourth through sixth implementations of the first aspect, in a seventh implementation of the first aspect, the time and frequency resource of the first reference signal includes R1 time and frequency resource units, the time and frequency resource of the second reference signal includes R2 time and frequency resource units, R1 being less than or equal to R2, R1 being an integer greater than or equal to 0, and R2 being a positive integer. When R1 is equal to 0, this indicates that no reference signal is carried during retransmission and no overhead is consumed. In this case, all resources can be used to transmit data, and reference signal overheads are the lowest.

[0017] With reference to any of the first to seventh implementations of the first aspect, in an eighth implementation of the first aspect, the first indication information is sent by using any of the physical layer control signaling, radio resource control layer signaling, and medium access control layer signaling.

[0018] With reference to any of the fourth to seventh implementations of the first aspect, in a ninth implementation of the first aspect, the second indication information is sent using any of the physical layer control signaling, radio resource control layer signaling, and medium access control layer signaling.

[0019] According to a second aspect, one embodiment of this request provides a method of data transmission, and the method includes receiving, by a second device, the first indication information, where the first indication information is used to Petition 870250050106, dated 06 / 16 / 2025, p. 16 / 103 6 / 39 indicate a time and frequency resource of a first reference signal, and the first reference signal is used to perform channel estimation on the retransmitted data from the first data; and receive, by the second device, the retransmitted data.

[0020] According to the method provided in this respect, the second device receives the first indication information, the first indication information is used to indicate a time and frequency resource of a reference signal used to transmit the first data a second time or subsequently, and this time and frequency resource setting may be the same as or different from a time and frequency resource used for the initial transmission of the first data. When the time and frequency resource indicated by the first indication information is less than the time and frequency resource occupied by a reference signal used for the initial transmission of the first data, reference signal overheads can be reduced, and reference signal resource setting flexibility and data transmission efficiency are improved.

[0021] With reference to the second aspect, in a first implementation of the second aspect, the first indication information includes information used to indicate a time and frequency location of the first reference signal.

[0022] With reference to the first implementation of the second aspect, in a second implementation of the second aspect, time and frequency location information includes at least one of a frequency domain spacing, a frequency domain offset, a time domain spacing, and a time domain offset.

[0023] With reference to the second aspect, in a third implementation of the second aspect, the first piece of information of Petition 870250050106, dated 06 / 16 / 2025, page 17 / 103 The 7 / 39 indication is additionally used to indicate that a first device does not send the first reference signal.

[0024] With reference to any of the first to third implementations of the second aspect, in a fourth implementation of the second aspect, the method additionally includes receiving the second indication information, where the second indication information is used to indicate a time and frequency resource of a second reference signal, and the second reference signal is used to perform channel estimation in an initial transmission of the first data.

[0025] With reference to the fourth implementation of the second aspect, in a fifth implementation of the second aspect, the second indication information includes a time and frequency location of the second reference signal.

[0026] With reference to the fifth implementation of the second aspect, in a sixth implementation of the second aspect, time and frequency location information includes at least one of a frequency domain spacing, a frequency domain offset, a time domain spacing, and a time domain offset.

[0027] With reference to any of the fourth to sixth implementations of the second aspect, in a seventh implementation of the second aspect, the time and frequency resource of the first reference signal includes R1 time and frequency resource units, the time and frequency resource of the second reference signal includes R2 time and frequency resource units, R1 being less than or equal to R2, R1 being an integer greater than or equal to 0, and R2 being a positive integer. When R1 is equal to 0, this indicates that no reference signal is carried during retransmission and no overhead is consumed. In this case, all resources can be used for data transmission, and signal overheads of Petition 870250050106, dated 06 / 16 / 2025, p. 18 / 103 8 / 39 references are the smallest.

[0028] With reference to any of the first to seventh implementations of the second aspect, in an eighth implementation of the second aspect, the second device receives the first indication information by using any of physical layer control signaling, radio resource control layer signaling, and medium access control layer signaling.

[0029] With reference to any of the fourth to seventh implementations of the second aspect, in a ninth implementation of the second aspect, the second device receives the second indication information by using any of the physical layer control signaling, radio resource control layer signaling, and medium access control layer signaling.

[0030] According to a third aspect, an embodiment of this application provides a first device. The first device may serve as a sending device, and the device has a function of implementing the first aspect and the first to ninth implementations of the first aspect. The function may be implemented by using hardware, or it may be implemented by executing corresponding software on hardware. The hardware or software includes one or more modules corresponding to the above function.

[0031] In a possible project, the first device includes an acquisition unit and a transmission unit. The acquisition unit is configured to obtain the first indication information, where the first indication information is used to indicate a time and frequency resource of a first reference signal, and the first reference signal is used to perform channel estimation on retransmitted data from the first data. The transmission unit is configured to send the first indication information. The transmission unit is additionally configured to send the retransmitted data. Petition 870250050106, dated 06 / 16 / 2025, page 19 / 103 9 / 39

[0032] In a possible project, the sending unit is additionally configured to implement functions implemented by the first device in the first to ninth implementations of the first aspect.

[0033] According to the fourth aspect, an embodiment of this application provides a second device. The second device may serve as a receiving device, and the device has a function implementing the second aspect and the first to ninth implementations of the second aspect. The function may be implemented by using hardware, or it may be implemented by running corresponding software on hardware. The hardware or software includes one or more modules corresponding to the above function.

[0034] In a possible design, the second device includes a receiving unit and a processing unit. The receiving unit is configured to receive the first indication information, where the first indication information is used to indicate a time and frequency feature of a first reference signal, and the first reference signal is used to perform channel estimation on retransmitted data from the first data. The processing unit is configured to determine the time and frequency feature of the first reference signal based on the first indication information. The receiving unit is additionally configured to receive the retransmitted data.

[0035] In a possible project, the receiving unit is additionally configured to implement the functions implemented by the second device in the first to ninth implementations of the second aspect.

[0036] According to a fifth aspect, an embodiment of the present invention provides a first device, and the first device can serve as a sending device. The first device includes a processor and a transmitter. The processor is configured to support Petition 870250050106, dated 06 / 16 / 2025, p. 20 / 103 10 / 39 The first device implements the functions of the acquisition unit in third-aspect mode, and the transmitter is configured to implement the functions of the sending unit in third-aspect mode. The first device may additionally include memory. The memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are required for the first device.

[0037] According to a sixth aspect, an embodiment of the present invention provides a second device, and the second device may serve as a receiving device. The second device includes a processor and a transceiver. The processor is configured to support the second device in implementing processing unit functions in the embodiment of the fourth aspect, and the transceiver is configured to implement receiving unit functions in the embodiment of the fourth aspect. The second device may additionally include a memory. The memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are required for the second device.

[0038] According to a seventh aspect, an embodiment of this application additionally provides a computer storage medium. The computer storage medium stores a program, and when the program is executed, some or all of the steps in implementing the data transmission methods, according to the first aspect and the second aspect, are performed.

[0039] According to an eighth aspect, a computer program product, including an instruction, is provided and, when the computer program product runs on a computer, the computer performs the method according to any one of the first aspect or possible implementations of the first aspect. Petition 870250050106, dated 06 / 16 / 2025, page 21 / 103 11 / 39

[0040] According to a ninth aspect, a computer program product including an instruction is provided, and when the computer program product runs on a computer, the computer performs the method according to either of the second aspect or possible implementations of the second aspect.

[0041] According to the method and data transmission apparatus provided in this application, the sending device indicates a time and frequency resource of a reference signal used for data transmission, to improve the configuration flexibility of the time and frequency resource of the reference signal and improve data transmission efficiency, and adapt to a new service such as URLLC and a new application situation. Additionally, in the frequency domain, a frequency domain spacing between the reference signals is configured to increase, to reduce overheads of the time and frequency resource occupied by the reference signal, and improve data transmission efficiency.Additionally, the initial indication information is used to indicate that the reference signal has a frequency domain deviation, so that a frequency domain location of a reference signal, used for initial data transmission, and a frequency domain location of a reference signal, used for data retransmission, is staggered, thus further improving the accuracy of the signal estimate performed by the receiving device. Brief Description of the Drawings

[0042] Figure 1 is a schematic diagram of a transmission latency in a URLLC service, according to one modality of that request;

[0043] Figure 2 is a schematic diagram of a communications system situation that is applied to a transmission method. Petition 870250050106, dated 06 / 16 / 2025, page 22 / 103 12 / 39 of data, according to one modality of this request;

[0044] Figure 3 is a schematic diagram of a time and frequency resource of a reference signal, according to one embodiment of that request;

[0045] Figure 4 is a schematic flowchart of a data transmission method, according to one modality of this request;

[0046] Figure 5 is a schematic diagram illustrating that a frequency domain spacing between reference signals in the retransmission of the first data increases with respect to a frequency domain spacing between reference signals in the initial transmission of the first data, according to one embodiment of that request;

[0047] Figure 6 is a schematic diagram illustrating that a reference signal in the retransmission of the first data exhibits a frequency domain deviation relative to a reference signal in the initial transmission of the first data, according to one embodiment of that request;

[0048] Figure 7 is a schematic diagram indicating that no reference signal is carried in subsequent transmission, in accordance with one embodiment of this request;

[0049] Figure 8 is a schematic diagram indicating a time and frequency resource of a subsequent reference signal, according to an embodiment of that request;

[0050] Figure 9 is a schematic diagram of a reference signal indication that is oriented in the return information, according to a modality of that request;

[0051] Figure 10 is a schematic diagram of another reference signal indication, according to an embodiment of this application;

[0052] Figure 11 is a schematic flowchart of another data transmission method, according to one modality of this request; Petition 870250050106, dated 06 / 16 / 2025, page 23 / 103 13 / 39

[0053] Figure 11A is a schematic diagram of the reuse of the reference signal, according to one embodiment of this application;

[0054] Figure 12 is a schematic structural diagram of a data transmission device, according to one embodiment of this application;

[0055] Figure 13 is a schematic structural diagram of a first device, according to an embodiment of this application; and

[0056] Figure 14 is a schematic structural diagram of a second device, according to an embodiment of this application. Description of Embodiments

[0057] The following clearly and completely describes the technical solutions in the embodiments of this application with reference to the attached drawings in the embodiments of this application.

[0058] The embodiments of this application apply to a communications system including at least one first device that serves as a sending device and at least one second device that serves as a receiving device. The sending device and the receiving device may be, respectively, any transmitting end device and any receiving end device that transmits data wirelessly. The sending device and the receiving device may be any device possessing a wireless receive / send function, including but not limited to: a B Node, an evolved B Node (eNodeB), a base station in a 5th generation communications system (the fifth generation, 5G), a base station or network device in a future communications system, an access node in a Wi-Fi system, a wireless relay node, a wireless return access channel node, and user equipment (user equipment, UE).

[0059] The UE can also be referred to as a terminal, a mobile station (mobile station, MS), a mobile terminal (mobile terminal, Petition 870250050106, dated 06 / 16 / 2025, page 24 / 103 14 / 39 MT), a remote terminal (remote terminal, RT), an access terminal (access terminal, AT), a user agent (user agent, UA), or similar. The UE may communicate with one or more core networks by using a radio access network (radio access network, RAN), or it may access a self-organized or concession-free distributed network; or the UE may access a wireless network in another way for communication; or the UE may directly perform wireless communication with another UE. This is not limited to the embodiments of the present invention.

[0060] A data transmission method provided in the embodiments of this application can be applied to downlink data transmission, can be applied to uplink data transmission, and can also be applied to device-to-device (D2D) data transmission. For downlink data transmission, a sending device is a base station, and a corresponding receiving device is a UE. For uplink data transmission, a sending device is a UE, and a corresponding receiving device is a base station. For D2D data transmission, a sending device is the UE, and a corresponding receiving device is also the UE. This is not limited to the embodiments of the present invention.

[0061] The sending device and the receiving device in the embodiments of this application may be developed on land, for example, an indoor device, an outdoor device, a portable device or a vehicular device; it may be developed on a water surface; or it may be developed on a plane, a balloon, and a satellite in the air. The UE in the embodiments of the present invention may be a mobile phone (mobile phone), a tablet computer (Pad), a computer having a wireless sending / receiving function, a virtual reality terminal device (Virtual Reality, VR), a Petition 870250050106, dated 06 / 16 / 2025, page 25 / 103 15 / 39 augmented reality terminal device (Augmented Reality, AR), a wireless terminal in industrial control (industrial control), a wireless terminal in automatic drive (automatic drive), a wireless terminal in telemedicine (remote doctor), a wireless terminal in a smart facility (smart facility), a wireless terminal in transport security (transport security), a wireless terminal in a smart city (smart city), a wireless terminal in a smart home (smart home), or similar.

[0062] The data transmission method is provided in the embodiments of this application and can be applied to various communication systems, such as a 4G system, a 4.5G system and a 5G system. An application situation not limited in this application.

[0063] As illustrated in Figure 2, an embodiment provides a communications system situation that is applied to the data transmission method, and this application situation includes a base station and at least one terminal device. The base station can be a node in a cellular network that provides a data access service to the terminal device, and the terminal device can be composed of several UEs that communicate with the base station on the cellular network.

[0064] The data transmission method provided in the modalities can be applied to data transmission, such as a URLLC service or an eMBB service. In the URLLC service, the time interval between an initial transmission and retransmission of data is very short, and typically does not exceed a latency of 1 ms, and a channel changes very little in a data transmission process. Based on this characteristic, a time and frequency resource of a reference signal used for data transmission is indicated by the use of indication information, so that flexibility Petition 870250050106, dated 06 / 16 / 2025, page 26 / 103 16 / 39 resource configuration and data transmission efficiency are improved.

[0065] Figure 3 is a schematic diagram of a time and frequency resource of a reference signal. A physical resource block (physical resource block, PRB) includes a plurality of (e.g., 84) resource elements (resource element, RE), and each RE can be used to carry a reference signal symbol. Figure 3 illustrates the quantity and locations of reference signal symbols configured in a PRB in a partition. In a first time domain symbol, two adjacent reference signal symbols are separated by six subcarriers (5 REs), and a reference signal symbol in a last symbol, however, two domain symbols and a reference signal symbol in the first domain symbol are separated by three subcarriers in the frequency domain.The time-domain symbol here can be an orthogonal frequency-division multiplexing (OFDM) symbol, or it can be a single-carrier frequency-division multiplexing (SC-FDMA) symbol.

[0066] Additionally, as illustrated in figure 4, a method provided in an embodiment includes the following steps.

[0067] Step 101: A first device sends the first indication information, where the first indication information is used to indicate a time and frequency feature of a first reference signal, and the first reference signal is used to perform channel estimation on the retransmitted data from the first data.

[0068] Optionally, the first device sends the second indication information. The second indication information is used to indicate a time and frequency feature of a second signal. Petition 870250050106, dated 06 / 16 / 2025, page 27 / 103 17 / 39 reference, and the second reference signal is used to perform channel estimation in an initial transmission of the first data.

[0069] Optionally, the time and frequency feature of the first reference signal includes time and frequency feature units R1, the time and frequency feature of the second reference signal includes R1 time and frequency feature units, the time and frequency feature of the third reference signal includes R2 time and frequency feature units, R1 is less than or equal to R2, R1 is an integer greater than or equal to 0, and R2 is a positive integer. The unit of time and frequency features here may be RE.

[0070] The first device can simultaneously send the first indication information and the second indication information, or it can send the first indication information and the second indication information sequentially. For example, the first device sends the second indication information first, and then sends the first indication information. This is not limited in this mode.

[0071] Step 102: The first device sends the relayed data.

[0072] The first indication and second indication information can be sent using any of the following: physical layer control signaling, radio resource control (RRC) layer signaling, and medium access control (MAC) layer signaling. Physical layer control signaling has the highest real-time performance but high signaling overheads. RRC layer signaling has lower overheads but higher latency. The specific signaling within the three signaling types above that is used to send the first indication and / or the second indication information is determined by the signaling method used to send the first indication and / or the second indication. Petition 870250050106, dated 06 / 16 / 2025, page 28 / 103 18 / 39 indication can be determined based on a requirement and an application situation.

[0073] Specifically, in step 101, the first device sends the first indication information, the first indication information includes information used to indicate a time and frequency location of the first reference signal, and the time and frequency location information includes at least one of a frequency domain spacing, a frequency domain offset, a time domain spacing, and a time domain offset.

[0074] The first indication information indicates the time and frequency location of the first reference signal in two ways. One way is an absolute indication form. To be specific, the time and frequency location of the first reference signal in a feature block is indicated directly, for example, it can be indicated in the following three dimensions: a time and frequency location of a first reference signal symbol in an RB, a frequency domain spacing between two adjacent reference signal symbols, and a time domain spacing between two adjacent reference signal symbols. The frequency domain spacing is a quantity of REs, and the time domain spacing is a quantity of time domain symbols. The other way is a relative indication form.To be specific, a change in the time and frequency location of the first reference signal relative to a time and frequency location of the second reference signal is indicated. Specifically, at least one of the following may be indicated: a frequency-domain spacing change, a frequency-domain deviation, a time-domain spacing change, and a time-domain deviation. Petition 870250050106, dated 06 / 16 / 2025, page 29 / 103 19 / 39 time domain.

[0075] Configuration method 1: Configure a frequency domain spacing between the reference signals in the retransmission to be increased.

[0076] Figure 5 is a schematic diagram illustrating that a frequency domain spacing between reference signals in the retransmission of the first data increases relative to a frequency domain spacing between reference signals in the initial transmission of the first data. During the initial transmission of the first data, a location spacing between two adjacent reference signal symbols in the same time domain symbol is one RE. During retransmission, a spacing between two adjacent reference signal symbols is three REs, and thus, the time and frequency resources occupied by the reference signals during retransmission are reduced, and overheads are reduced.

[0077] Configuration method 2: Configure a reference signal in the retransmission to have a frequency domain deviation.

[0078] Figure 6 is a schematic diagram illustrating that a reference signal in the retransmission of the first data has a frequency domain deviation relative to a reference signal in the initial transmission of the first data. A first reference signal symbol sent by the first device has a frequency domain deviation of one RE relative to a second reference signal symbol, so that a frequency domain location of a reference signal symbol in the retransmission and a frequency domain location of a reference signal symbol in the initial transmission are staggered, thus further improving the accuracy of the channel estimate performed by a second device. Petition 870250050106, dated 06 / 16 / 2025, page 30 / 103 20 / 39

[0079] Configuration method 3: Configure a frequency domain spacing between the reference signals in the retransmission to be increased, and configure the reference signal to have a frequency domain deviation.

[0080] The first indication sent by a transmitting device is used to indicate that a frequency domain spacing between the first reference signals is greater than a frequency domain spacing between the second reference signals, in order to reduce reference signal overhead during retransmission. Additionally, the first indication sent by the transmitting device is used to indicate that the first reference signal has a frequency domain deviation relative to the second reference signal, so that the first reference signal and the second reference signal are staggered in the frequency domain, thus improving the accuracy of channel estimation by a receiving device.

[0081] It should be noted that a specific form among the three configuration forms above, which is specifically used by the first device, may be determined based on a current number of transmission times or a sequence number of a redundancy version. This is not limited to this modality of this application.

[0082] A time and frequency feature location of a reference signal can alternatively be determined and configured using a formula. For example, Figure 3 illustrates a method for configuring a time and frequency feature of a reference signal, and a frequency domain location of each reference signal is configured using a predefined formula.

[0083] According to the data transmission method provided Petition 870250050106, dated 06 / 16 / 2025, page 31 / 103 21 / 39 in this application, for a feature in which a wireless channel of a user service changes very slightly in a short latency, the sending device configures a time and frequency resource of a reference signal used to retransmit data so that they are different from a time and frequency resource of a reference signal used to initially transmit the data, to improve the configuration flexibility of the time and frequency resource of the reference signal and improve data transmission efficiency, and adapt to a new service, such as a URLLC service and a new application situation.Additionally, the first indication information is used to indicate that there is a frequency domain deviation between the first reference signal and the second reference signal, so that a frequency domain location of the reference signal used to initially transmit the data and a frequency domain location of the reference signal used to retransmit the data are staggered, thus further improving the accuracy of the signal estimate performed by the receiving device.

[0084] In another embodiment of this request, in order to further reduce reference signal resource overhead, during retransmission, no reference signal is sent, and no reference signal overhead is consumed.

[0085] As illustrated in Figure 7, the first indication sent by the first device is additionally used to indicate that the first reference signal is not sent during the retransmission of the first data. For example, in a second and a third transmission of the first data, the first indication indicates that the reference signal is configured in neither the time nor frequency resources, and R1 is equal to 0, thus greatly reducing the reference signal overheads. Petition 870250050106, dated 06 / 16 / 2025, page 32 / 103 22 / 39 comparison with an existing method in which the same reference signal configuration is used in each transmission of the first data.

[0086] With reference to Figure 8, this application further provides an embodiment of a method for transmitting the first data four times. To reduce resource signal overhead and ensure channel estimation quality, when the first device retransmits the first data, a reference signal is set on some retransmission, and no reference signal is set on some other retransmission.

[0087] As illustrated in Figure 8, the indication information sent by the first device indicates that no reference signal is sent in a second transmission and a fourth transmission of the first data, and a reference signal is set in an initial transmission and a third transmission of the first data. Additionally, to improve the accuracy of the channel estimate performed by the second device, in the third transmission of the first data, the first reference signal has a time domain deviation relative to the second reference signal. The second reference signal is located at a first domain symbol in a transmission, and the first reference signal is located at a second time domain symbol in a transmission.

[0088] In another additional mode, when the first indication information is sent, the first device additionally receives return information for the transmission of the first data from the second device. The return information includes an acknowledgement of receipt (ACK) and a negative acknowledgement of receipt (NACK). As illustrated in Figure 9, the first device generates the first indication information based on the ACK / NACK return information. When the Petition 870250050106, dated 06 / 16 / 2025, page 33 / 103 23 / 39 Receiving the NACK information from the second device, the first device generates the first indication information and sends the first indication information to the second device.

[0089] Additionally, the first device may blindly retransmit the first data, to be specific, actively retransmit the first data before receiving ACK / NACK returned by the second device. Correspondingly, the first device sends the first indication information to indicate a time and frequency feature of the first reference signal used by the first device to retransmit the first data.

[0090] An embodiment of this application further provides a method for determining a time and frequency feature of a reference signal in a predefined manner. A first device and a second device predefine a time and frequency feature of a reference signal used in each data transmission, and the first device does not need to send the indication information to the second device, thus reducing control signaling overheads.

[0091] Specifically, it is predefined that the time and frequency resource of the reference signal used in each data transmission may be equal to a time and frequency resource of a reference signal, and that this is indicated in the above embodiments. For example, a frequency domain spacing between two adjacent reference signal symbols to a reference signal used in the initial transmission of the first data is equal to 2, and a frequency domain spacing between two adjacent reference signal symbols to a reference signal used in the retransmission of the first data is equal to 4. If a time interval between the retransmission of the first data and the initial transmission of the first data is greater than a time limit, for example, 1 ms, the Petition 870250050106, dated 06 / 16 / 2025, p. 34 / 103 24 / 39 frequency domain spacing between two reference signal symbols adjacent to the reference signal used in the retransmission of the first data is reconfigured as two REs. Additionally, a frequency domain deviation of a reference signal symbol can also be linked to a number of first data transmission moments. For example, a frequency domain deviation of a reference signal used in a first retransmission of the first data is configured to one RE, and a frequency domain deviation of a reference signal used in a second retransmission of the first data is configured to three REs.Frequency domain shifting is configured so that a frequency domain location of a reference signal used to retransmit data and a frequency domain location of a reference signal used to initially transmit the data are staggered, thereby improving the accuracy of a channel estimation result.

[0092] Figure 10 illustrates time and frequency resource configurations of reference signals used for the initial transmission and retransmission of the first data. In an initial transmission, the frequency domain spacing between the second reference signals is two REs, and the frequency domain deviation is equal to 0. In a second transmission, the frequency domain spacing between the first reference signals is four REs, and the frequency domain deviation is equal to one RE. In a third transmission, the frequency domain spacing between the first reference signals is four REs, and the frequency domain deviation is three REs. A sending device can notify a receiving device of a time and frequency resource of a reference signal by using a signaling notification, or a time and frequency resource of a reference signal used Petition 870250050106, dated 06 / 16 / 2025, page 35 / 103 25 / 39 in each data transmission can be predefined in the manner described above. The signaling notification can be physical layer signaling, medium access control layer signaling, or radio resource control layer signaling.

[0093] One embodiment additionally provides a method of data transmission, and the method is applied to a second device. Specifically, as illustrated in Figure 11, the method includes the following steps.

[0094] Step 201: The second device receives the first indication information, where the first indication information is used to indicate a time and frequency resource of a first reference signal, and the first reference signal is used to perform channel estimation on the retransmitted data from the first data. The second device determines, based on the first indication information, the time and frequency resource of the first reference signal used to retransmit the data.

[0095] After receiving the first indication information, the second device obtains a time and frequency location of the first reference signal, and performs, based on the first reference signal, channel estimation on a wireless channel through which the first data is retransmitted.

[0096] Step 202: The second device receives the retransmitted data.

[0097] The first indication information includes information used to indicate the time and frequency location of the first reference signal, and the time and frequency location information includes at least one of a frequency domain spacing, a frequency domain deviation, a time domain spacing, and a time domain deviation. Additionally, the first indication information may be further used. Petition 870250050106, dated 06 / 16 / 2025, page 36 / 103 26 / 39 to indicate that a first device does not send the first reference signal.

[0098] Additionally, the method includes: receiving the second indication information, where the second indication information is used to indicate a time and frequency resource of a second reference signal, and the second reference signal is used to perform channel estimation in an initial transmission of the first data.

[0099] The time and frequency resource of the first reference signal includes R1 time and frequency resource units, the time and frequency resource of the second reference signal includes R2 time and frequency resource units, R1 is less than or equal to R2, R1 is an integer greater than or equal to 0, and R2 is a positive integer. When R1 is equal to 0, this indicates that the first reference signal is not sent, and the reference signal overheads are the lowest. A saved time and frequency resource can be used for data transmission, thus improving data transmission efficiency.

[0100] Additionally, the method provided in this modality includes:

[0101] Receive, by the second device, data initially transmitted from the first data or data retransmitted from the first data, and generate an ACK / NACK verification result; if the data initially transmitted from the first data or the data retransmitted from the first data is correctly received, generate an ACK, or otherwise, generate a NACK; and send, by the second device, the ACK / NACK to the first device.

[0102] Additionally, the second device can further obtain a frequency domain spacing between the reference signals and a frequency domain deviation of a reference signal. Petition 870250050106, dated 06 / 16 / 2025, page 37 / 103 27 / 39 through blind detection. Both a possible frequency domain spacing and a possible frequency domain deviation of the reference signal are known. Therefore, a combination of a frequency domain spacing and a frequency domain deviation is also known. The second device can blindly detect the reference signal based on a combination of possible frequency domain spacing and frequency domain deviation.

[0103] The second device can, alternatively, obtain, by using a combination of the various methods above, information about a time and frequency resource of a reference signal used in the transmission of current data.

[0104] It can be understood that the data transmission method applied above to the second device corresponds to the data transmission method applied above to the first device. For implementations and steps above, refer to the corresponding method modality of the first device. Details will not be described again here.

[0105] In the above mode, when a time interval between retransmission and the initial transmission of the first data is less than a predefined limit, for example, 1 ms, during the reception of the retransmitted data from the first data, the second device can reuse a channel estimation result obtained by using a second reference signal during the initial transmission of the first data. In other words, the second device demodulates the retransmitted data from the first data, using the channel estimation result obtained during the initial transmission of the first data. Correspondingly, the first device may not send the first reference signal when retransmitting the first data. Petition 870250050106, dated 06 / 16 / 2025, p. 38 / 103 28 / 39

[0106] If the control information sent by the first device to the second device carries valid time reference signal information, and the first device has sent data within a valid time window, the second device can demodulate the control information using a channel estimate result in temporary memory to determine if there is data for the second device in the current transmission. If a valid time reference signal expires, the second device can discard the channel estimate result in temporary memory. If there is no reference signal in the subsequent data transmission, the second device may be unable to correctly demodulate subsequently transmitted data. The valid time is not limited to a fixed value, and the valid time can be changed by using control signaling.

[0107] In this mode, the valid time of the reference signal is configured, so that the second device can determine, based on the valid time information, whether to use a previous channel estimation result, thus further improving the accuracy of the channel estimation result.

[0108] It should be noted that the method provided in the above embodiment includes, but is not limited to, a URLLC service, and this solution can also be used for another service if a channel changes slightly between a plurality of transmission moments. A definition of the plurality of transmission moments is not limited to the initial transmission and retransmission. If a user needs to send a plurality of consecutive data packets, the same frequency domain resource is used, a time interval between two initial transmission moments is relatively short, and a channel changes slightly, this solution is also applicable.

[0109] It can be understood that the method modalities Petition 870250050106, dated 06 / 16 / 2025, p. 39 / 103 29 / 39 above are not limited to the reuse of a reference signal between retransmission and the initial transmission. More generally, the modalities of the above method can be used for reuse of a reference signal between an (N+M)th transmission and an Nth transmission of the first data. Both N and M are positive integers.

[0110] When a frequency domain feature used in the (N+M) transmission of the first data overlaps with a frequency domain feature used in the N transmission of the first data, for an overlapping part of the (N+M) transmission and the N transmission in the frequency domain, a reference signal used in the (N+M) transmission can be obtained with reference to the modalities of the method above: more specifically, the reuse of the reference signal between two transmission moments is performed with reference to the modalities above; and for a non-overlapping area, a reference signal used in the (N+M) transmission can be obtained with reference to the modalities of the method above or can be determined separately.For the non-overlapping area, if a reference signal used in the nth transmission is reused in the (N+M)th transmission, according to the modalities of the method above, the data reception performance may be affected in some situations. Therefore, the reference signal used in the (N+M)th transmission in the non-overlapping area can be determined separately.

[0111] Figure 11A is a schematic diagram of the reuse of a reference signal, according to one embodiment of this application. As illustrated in Figure 11A, in a frequency domain overlap area, a reference signal used in a transmission of the first N data is reused, using the methods illustrated in Figures 5 to 10, as a reference signal used in a transmission of the first (N+M) data; and in an area Petition 870250050106, dated 06 / 16 / 2025, p. 40 / 103 30 / 39 non-overlapping, a reference signal used in the transmission (N + M) of the first data is determined separately. The reference signal in the non-overlapping area can be predefined, or it can be determined by the first indication information or the second indication information in the above method modes.

[0112] As illustrated in Figure 12, one embodiment additionally provides a data transmission apparatus. The data transmission apparatus is configured to implement the functions of the first device that serves as a sending device in the above method embodiments, and the apparatus includes a receiving unit 1201 and a sending unit 1202.

[0113] The 1201 acquisition unit is configured to obtain the first indication information. The first indication information is used to indicate a time and frequency resource of a first reference signal, and the first reference signal is used to perform channel estimation on the retransmitted data from the first data.

[0114] The 1202 transmission unit is configured to send the first prompt information, and is additionally configured to send the retransmitted data.

[0115] Additionally, the first indication information includes information used to indicate a time and frequency location of the first reference signal, and the time and frequency location information includes at least one of a frequency domain spacing, a frequency domain offset, a time domain spacing, and a time domain offset. Additionally, the first indication information may be further used to indicate that the first device does not transmit the first reference signal.

[0116] Additionally, the 1202 transmission unit is further configured to send the second indication information. The second Petition 870250050106, dated 06 / 16 / 2025, page 41 / 103 31 / 39 indication information is used to indicate a time and frequency resource of a second reference signal, and the second reference signal is used to perform channel estimation in an initial transmission of the first data. The time and frequency resource of the first reference signal includes R1 time and frequency resource units, the time and frequency resource of the second reference signal includes R2 time and frequency resource units, R1 is less than or equal to R2, R1 is an integer greater than or equal to 0, and R2 is a positive integer.

[0117] Additionally, the 1202 transmission unit is further configured to transmit the first indication information and / or the second indication information by using any of the physical layer control signaling, radio resource control layer signaling, and medium access control layer signaling.

[0118] Optionally, the device additionally includes a 1203 receiving unit, configured to receive ACK / NACK information from a second device.

[0119] Optionally, the 1201 acquisition unit generates the first indication information based on the NACK information received from the second device.

[0120] Additionally, the 1201 acquisition unit is configured to generate the first indication information, and can be further configured to generate the second indication information. Additionally, the 1201 acquisition unit is further configured to generate the first indication information based on the NACK information received from the second device. Optionally, the 1201 acquisition unit can be further configured to generate the second indication information based on the ACK information received from the second device. Petition 870250050106, dated 06 / 16 / 2025, page 42 / 103 32 / 39

[0121] As illustrated in Figure 13, one embodiment additionally provides another data transmission apparatus. The data transmission apparatus is used to implement the functions of the second device, which serves as a receiving device in the embodiments of the method above. The apparatus includes a receiving unit 1301 and a processing unit 1302.

[0122] Receiving unit 1301 is configured to receive the first indication information. The first indication information is used to indicate a time and frequency resource of a first reference signal, and the first reference signal is used to perform channel estimation on the retransmitted data from the first data.

[0123] Processing unit 1302 is configured to determine the time and frequency feature of the first reference signal based on the first indication information.

[0124] Receiving unit 1301 is additionally configured to receive the retransmitted data.

[0125] Optionally, the first indication information includes information used to indicate a time and frequency location of the first reference signal, and the time and frequency location information includes at least one of a time domain spacing, and a time domain offset.

[0126] After receiving unit 1301 receives the first indication information, processing unit 1302 determines the time and frequency location of the first reference signal based on the information about the time and frequency location of the first reference signal.

[0127] Additionally, processing unit 1302 further performs, based on the first reference signal, channel estimation on a wireless channel through which the first data is Petition 870250050106, dated 06 / 16 / 2025, page 43 / 103 33 / 39 retransmitted.

[0128] The first indication information includes the information used to indicate the time and frequency location of the first reference signal, and the time and frequency location information includes at least one of a frequency domain spacing, frequency domain deviation, time domain spacing, and time domain deviation. Additionally, the first indication information may be further used to indicate that a first device does not transmit the first reference signal.

[0129] Additionally, receiving unit 1301 is further configured to receive the second indication information. The second indication information is used to indicate a time and frequency resource of a second reference signal, and the second reference signal is used to perform channel estimation in an initial transmission of the first data. Processing unit 1302 is further configured to estimate a channel situation of the initial transmission based on the second indication information.

[0130] The time and frequency resource of the first reference signal includes R1 time and frequency resource units, the time and frequency resource of the second reference signal includes R2 time and frequency resource units, R1 is less than or equal to R2, R1 is an integer greater than or equal to 0, and R2 is a positive integer. When R1 is equal to 0, this indicates that the first reference signal was not sent, and the reference signal overheads are the lowest. A saved time and frequency resource can be used for data transmission, thus improving data transmission efficiency.

[0131] Additionally, receiving unit 1301 is further configured to receive initially transmitted data from the first data or retransmitted data from the first data. A Petition 870250050106, dated 06 / 16 / 2025, p. 44 / 103 34 / 39 processing unit 1302 is additionally configured to verify that the initial data is received correctly, generate an ACK / NACK verification result, and generate an ACK if the initial data is received correctly, or generate a NACK if the initial data is not received correctly. A sending unit 1303 is configured to send the verification result.

[0132] The data transmission devices illustrated in Figure 12 and Figure 13 are divided in terms of function. In a real-world application situation, a data transmission device structure can alternatively be divided from a hardware perspective. When the functions of the data transmission device are divided from a hardware perspective, the data transmission devices illustrated in Figures 12 and 13 can have the same hardware structure. For example, both data transmission devices are UEs, one UE serves as a first device, and the other UE serves as a second device. Of course, the data transmission devices illustrated in Figure 12 or 13 can have different hardware structures. For example, the device illustrated in Figure 12 is a UE and the device illustrated in Figure 13 is a base station.It should be noted that in different communication processes, the roles of the device illustrated in Figure 12 and the device illustrated in Figure 13 may also be interchangeable. Based on this, the hardware structures of the data transmission devices illustrated in Figures 12 and 13 are described below using a specified device.

[0133] Figure 14 is a schematic structural diagram of another data transmission apparatus according to an embodiment of the present invention. The data transmission apparatus illustrated in Figure 14 illustrates a transmitter / receiver 1401, a controller / processor 1402, a memory 1403, and a communications unit 1404. The Petition 870250050106, dated 06 / 16 / 2025, page 45 / 103 The 35 / 39 transmitter / receiver 1401 is configured to support radio communication between the device and both a non-hierarchical device and another network device.

[0134] When the data transmission apparatus illustrated in Figure 14 is used as a hardware implementation structure of the data transmission apparatus illustrated in Figure 12, the transmitter / receiver 1401 is configured to implement the functions of the sending unit 1202 and the receiving unit 1203 in Figure 12, and the controller / processor 1402 is configured to implement a function of the receiving unit 1201 in Figure 12. The memory 1403 is configured to store a program. Specifically, the program may include program code, and the program code includes a computer operation instruction. The memory 1403 may include random access memory (random access memory, RAM for short), and may additionally include non-volatile memory (non-volatile memory), for example, at least one magnetic disk storage device.The controller / processor 1402 executes the program stored in memory 1403, to implement the functions performed by the first device in the method modes.

[0135] When the data transmission apparatus illustrated in Figure 14 is used as a hardware implementation structure of the data transmission apparatus illustrated in Figure 13, the transmitter / receiver 1401 is configured to implement the functions of the sending unit 1303 and the receiving unit 1301 in Figure 13, and the controller / processor 1402 is configured to implement a function of the processing unit 1302 in Figure 13. The memory 1403 is configured to store a program. Specifically, the program may include program code, and the program code includes a computer operation instruction. The memory 1403 may include random access memory. Petition 870250050106, dated 06 / 16 / 2025, page 46 / 103 36 / 39 (random access memory, RAM for short) and may additionally include non-volatile memory (non-volatile memory), for example, at least one magnetic disk storage device. The controller / processor 1402 executes the program stored in memory 1403, to implement functions performed by the second device in the method modes.

[0136] It may be understood that Figure 14 merely illustrates a simplified design of the data transmission apparatus. In actual application, the data transmission apparatus may include any number of transmitters, receivers, processors, controllers, memories, communication units or the like, and all data transmission apparatus that may implement the present invention are contained within the scope of protection of the present invention.

[0137] The controller / processor configured to perform the functions of the data transmission device described above in the present invention may be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The controller / processor may implement or execute various logic blocks, modules, and illustrative circuits described with reference to the content described in the present invention. Alternatively, the processor may be a combination of processors implementing a computing function, for example, a combination of one or more processors, or a combination of a DSP and a microprocessor.

[0138] It can be understood that when the modalities of this request are applied to a first device chip, the first device chip implements a function of the above obtaining unit. Petition 870250050106, dated 06 / 16 / 2025, page 47 / 103 37 / 39 1201 or a controller / processor function above 11402. The first device chip can send the first indication information and the second indication information to another module (e.g., a radio frequency module or an antenna) of the first device. The first indication information and the second indication information are sent by the other module of the first device to a second device. Optionally, the first device chip can additionally receive the NACK information above from another module (e.g., the radio frequency module or the antenna) of the first device, and the NACK information is sent by the second device to the first device.

[0139] When the embodiments of this application are applied to a second device chip, the second device chip implements a processing unit function above 1302 or a controller / processor function above 1402. The second device chip may receive the first indication information and the second indication information from another module (e.g., a radio frequency module or an antenna) of a second device, and the first indication information and the second indication information are sent by a first device to the second device. Optionally, the second device chip may additionally send the above NACK information to another module (e.g., the radio frequency module or antenna) of the second device, and the NACK information is sent by the other module of the second device to the first device.

[0140] The steps of the method in the embodiments of this application may be implemented in hardware form or may be implemented in the form of executing a software instruction by a processor. The software instruction may include a corresponding software module. The software module may be stored Petition 870250050106, dated 06 / 16 / 2025, page 48 / 103 38 / 39 in a random access memory (Random Access Memory, RAM), a flash memory, a read-only memory (Read-Only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), a programmable and erasable read-only memory (Electrical PROM, EPROM), an electrically programmable and erasable read-only memory (Electrical EPROM, EEPROM), a register, a hard disk, a removable hard disk, a CD-ROM, or a storage medium of any other form well known in the art. For example, a storage medium is coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. Certainly, the storage medium can be a component of the processor. The processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in a sending device or a receiving device.Certainly, the processor and storage medium can also exist within the sending or receiving device as discrete components.

[0141] All or some of the above embodiments may be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or some of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or some of the procedures or functions, according to the embodiments of the present invention, are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device. The computer instructions may be Petition 870250050106, dated 06 / 16 / 2025, page 49 / 103 39 / 39 stored on a computer-readable storage medium, or can be transmitted using a computer-readable storage medium. Computer instructions can be transmitted from one network site, computer, server, or data center to another network site, computer, server, or data center by wire (e.g., a coaxial cable, an optical fiber, or a digital subscriber line (DSL)) or wirelessly (e.g., infrared, radio, or microwave). The computer-readable storage medium can be any usable medium accessible by a computer, or a data storage device, such as a server or data center, integrating one or more usable media. The usable medium can be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a DVD), a semiconductor medium (e.g., a solid-state drive (SSD)), or similar.

[0142] It may be understood that the numerical symbols involved in the modalities of this application are differentiated merely to facilitate description, but are not used to limit the scope of the modalities of this application.

[0143] It can be understood that the sequence numbers of the processes above do not signify sequences in the modalities of this request. The execution sequences of the processes must be determined based on the functions and internal logic of the processes and should not be considered as any limitation of the implementation processes of the modality of this request.

[0144] The descriptions above are merely specific implementations of the embodiments of this application. Any variation or substitution readily highlighted by those skilled in the art within the technical scope described in this application shall be within the scope of protection of the embodiments of this application. Petition 870250050106, dated 06 / 16 / 2025, pp. 50 / 103

Claims

1 / 4 CLAIMS 1. Data transmission method, the method comprising: sending (101), by a first device, first indication information, wherein the first indication information is used to indicate a time-frequency feature of a first reference signal, and the first reference signal is used to perform channel estimation on retransmitted data from first data; and sending (102), by the first device, the retransmitted data; characterized in that the first indication information is further used to indicate that the first device sends the first reference signal in a first retransmission of the retransmitted data and does not send any reference signals in a second retransmission of the retransmitted data.

2. Method according to claim 1, characterized in that the initial indication information comprises information used to indicate a time frequency location of the first reference signal.

3. A method according to claim 2, characterized in that the time-frequency location information comprises at least one of a frequency domain spacing, a frequency domain deviation, a time domain spacing, and a time domain deviation.

4. Method, according to any one of claims 1 to 3, characterized in that the method further comprises: sending (101) second indication information, wherein the second indication information is used to indicate a time-frequency feature of a second reference signal, and the Petition 870250050106, dated 06 / 16 / 2025, page 51 / 103 2 / 4 second reference signal is used to perform channel estimation in an initial transmission of the first data.

5. Method according to claim 4, characterized in that: the time-frequency feature of the first reference signal comprises R1 time-frequency feature units, the time-frequency feature of the second reference signal comprises R2 time-frequency feature units, R1 is less than or equal to R2, R1 is an integer greater than or equal to 0, and R2 is a positive integer.

6. A method, according to any one of claims 1 to 5, characterized in that the initial indication information is sent using any one of physical layer control signaling, radio resource control layer signaling, and medium access control layer signaling.

7. A method according to claim 4 or 5, characterized in that the second indication information is sent using any one of physical layer control signaling, radio resource control layer signaling, and medium access control layer signaling.

8. Data transmission method, the method comprising: receiving (201), by a second device, first indication information, wherein the first indication information is used to indicate a time-frequency resource of a first reference signal, and the first reference signal is used to perform channel estimation on retransmitted data from first data; and Petition 870250050106, dated 06 / 16 / 2025, page 52 / 103 3 / 4 receiving (202), by the second device, the retransmitted data; characterized in that the first indication information is further used to indicate that the first device sends the first reference signal in a first retransmission of the retransmitted data and does not send any reference signals in a second retransmission of the retransmitted data.

9. Method according to claim 8, characterized in that the first indication information comprises information used to indicate a time frequency location of the first reference signal.

10. Method according to claim 9, characterized in that the time-frequency location information comprises at least one of a frequency domain spacing, a frequency domain deviation, a time domain spacing, and a time domain deviation.

11. Method, according to any one of claims 8 to 10, characterized in that it further comprises: receiving (201) second indication information, wherein the second indication information is used to indicate a time-frequency feature of a second reference signal, and the second reference signal is used to perform channel estimation in an initial transmission of the first data.

12. Method according to claim 11, characterized in that the time-frequency feature of the first reference signal comprises R1 units of time-frequency features, the time-frequency feature of the second reference signal comprises R2 units of time-frequency features, R1 is less than or equal to R2, R1 is an integer greater than or equal to 0, and R2 is a positive integer. Petition 870250050106, dated 06 / 16 / 2025, p. 53 / 103 4 / 4 13. Data transmission apparatus, characterized in that the apparatus comprises means adapted to perform the method as defined in any one of claims 1 to 7 or claims 8 to 12. Petition 870250050106, dated 06 / 16 / 2025, pp. 54 / 103

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