Repeated transmission method, terminal equipment and network equipment

Abstract

The embodiment of the invention provides a repeated transmission method, terminal equipment and network equipment. The repeated transmission method comprises the step that the terminal equipment receives repeated transmission of messages in a random access process. According to the embodiment of the invention, the success rate of random access can be improved based on repeated transmission of messages in the random access process.

Description

Repeated transmission method, terminal device and network device Technical Field

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

[0002] The random access process may include the process from when the terminal device sends a random access preamble to attempt to access the network to the establishment of a basic signaling connection with the network. There are many messages involved in the random access process, such as the Physical Random Access Channel (PRACH), Random Access Response (RAR) message, Physical Uplink Shared Channel (PUSCH), and Physical Downlink Shared Channel (PDSCH). Some messages in the current random access process do not support repeated transmission.

[0003] Summary of the Invention

[0004] This embodiment of the present application provides a repeated transmission method, including:

[0005] The terminal device receives repeated transmissions of messages during the random access procedure.

[0006] This embodiment of the present application provides a repeated transmission method, including:

[0007] The network device repeatedly transmits the message in the random access process.

[0008] An embodiment of the present application provides a terminal device, including:

[0009] The first processing unit is configured to receive repeated transmissions of a message in a random access process.

[0010] An embodiment of the present application provides a network device, including:

[0011] The processing unit is configured to repeatedly transmit the message in the random access process.

[0012] An embodiment of the present application provides a terminal device, comprising a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory, so that the terminal device executes the above-mentioned repeated transmission method.

[0013] An embodiment of the present application provides a network device, comprising a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory, so that the network device performs the above-mentioned repeated transmission method.

[0014] An embodiment of the present application provides a chip for implementing the above-mentioned repeated transmission method.

[0015] Specifically, the chip includes: a processor, configured to call and run a computer program from a memory, so that a device equipped with the chip executes the above-mentioned repeated transmission method.

[0016] An embodiment of the present application provides a computer-readable storage medium for storing a computer program. When the computer program is executed by a device, the device executes the above-mentioned repeated transmission method.

[0017] An embodiment of the present application provides a computer program product, including computer program instructions, which enable a computer to execute the above-mentioned repeated transmission method.

[0018] An embodiment of the present application provides a computer program, which, when executed on a computer, enables the computer to execute the above-mentioned repeated transmission method.

[0019] The embodiments of the present application are based on repeated transmission of messages during the random access process, which can improve the success rate of random access. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic diagram of an application scenario according to an embodiment of the present application.

[0021] FIG2 is a schematic diagram of an NTN system communication model according to an embodiment of the present application.

[0022] FIG3 is a schematic diagram of the RAR window startup timing of the NTN system according to an embodiment of the present application.

[0023] FIG4 is a schematic flowchart of a repeated transmission method according to an embodiment of the present application.

[0024] FIG5 is a schematic flowchart of a repeated transmission method according to an embodiment of the present application.

[0025] FIG6 is a schematic flowchart of a repeated transmission method according to an embodiment of the present application.

[0026] FIG7 is a schematic flowchart of a repeated transmission method according to an embodiment of the present application.

[0027] FIG8 is a schematic flowchart of a repeated transmission method according to an embodiment of the present application.

[0028] FIG9 is a schematic flowchart of a repeated transmission method according to an embodiment of the present application.

[0029] FIG10 is a schematic block diagram of a terminal device according to an embodiment of the present application.

[0030] FIG11 is a schematic block diagram of a terminal device according to an embodiment of the present application.

[0031] FIG12 is a schematic block diagram of a network device according to an embodiment of the present application.

[0032] FIG13 is a schematic block diagram of a network device according to an embodiment of the present application.

[0033] FIG14 is a schematic diagram of the RAR window startup timing according to an embodiment of the present application.

[0034] FIG15 is a schematic diagram of the process of UE receiving PDSCH repeated transmission according to an embodiment of the present application.

[0035] FIG16 is a schematic diagram of a PDSCH repeated transmission RV version according to an embodiment of the present application.

[0036] FIG17 is a schematic diagram showing that part of the PDSCH repeated transmission occurs outside the RAR window according to an embodiment of the present application.

[0037] FIG18 is a schematic diagram of the subsequent timing relationship of repeated transmission of Msg2 PDSCH according to an embodiment of the present application.

[0038] FIG19 is a schematic diagram of the subsequent timing relationship of Msg4 PDSCH repeated transmission according to an embodiment of the present application.

[0039] Figure 20 is a schematic block diagram of a communication device according to an embodiment of the present application.

[0040] FIG21 is a schematic block diagram of a chip according to an embodiment of the present application.

[0041] Figure 22 is a schematic block diagram of a communication system according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0043] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Global System of Mobile communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, Advanced Long Term Evolution (LTE-A) system, New Radio (NR) system, NR system evolution system, LTE on unlicensed spectrum (LTE-U) system, NR on unlicensed spectrum (NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (Wireless Fidelity) system. Fidelity, WiFi), fifth-generation communication (5th-Generation, 5G) system or other communication systems, etc.

[0044] Generally speaking, traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communications, but will also support, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, or vehicle-to-everything (V2X) communication, etc. The embodiments of the present application can also be applied to these communication systems.

[0045] In one embodiment, the communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, and a standalone (SA) networking scenario.

[0046] In one embodiment, the communication system in the embodiment of the present application can be applied to an unlicensed spectrum, wherein the unlicensed spectrum can also be considered as a shared spectrum; or, the communication system in the embodiment of the present application can also be applied to an authorized spectrum, wherein the authorized spectrum can also be considered as an unshared spectrum.

[0047] The embodiments of the present application describe various embodiments in conjunction with network devices and terminal devices, wherein the terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

[0048] The terminal device can be a station (STAION, ST) in a WLAN, a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a next-generation communication system such as an NR network, or a terminal device in a future evolved Public Land Mobile Network (PLMN) network, etc.

[0049] In an embodiment of the present application, the terminal device can be deployed on land, including indoors or outdoors, handheld, wearable or vehicle-mounted; it can also be deployed on the water surface (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.).

[0050] In an embodiment of the present application, the terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home, etc.

[0051] As an example and not a limitation, in the embodiment of the present application, the terminal device may also be a wearable device. Wearable devices may also be called wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0052] In an embodiment of the present application, the network device may be a device for communicating with a mobile device. The network device may be an access point (AP) in WLAN, a base station (BTS) in GSM or CDMA, a base station (NodeB, NB) in WCDMA, an evolved base station (eNB or eNodeB) in LTE, or a relay station or access point, or a vehicle-mounted device, a wearable device, and a network device (gNB) in an NR network, or a network device in a future evolved PLMN network or a network device in an NTN network, etc.

[0053] As an example and not a limitation, in an embodiment of the present application, the network device may have a mobile feature, for example, the network device may be a mobile device. Alternatively, the network device may be a satellite or a balloon station. For example, the satellite may be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network device may also be a base station set up in a location such as land or water.

[0054] In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0055] FIG1 exemplarily illustrates a communication system 100. The communication system includes a network device 110 and two terminal devices 120. In one embodiment, the communication system 100 may include multiple network devices 110, and each network device 110 may include a different number of terminal devices 120 within its coverage area, which is not limited in this embodiment of the present application.

[0056] In one embodiment, the communication system 100 may further include other network entities such as a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF), which is not limited in this embodiment of the present application.

[0057] Among them, the network equipment may include access network equipment and core network equipment. That is, the wireless communication system also includes multiple core networks for communicating with the access network equipment. The access network equipment can be an evolutionary base station (evolutional node B, abbreviated as eNB or e-NodeB) macro base station, micro base station (also called "small base station"), pico base station, access point (AP), transmission point (TP) or new generation base station (new generation Node B, gNodeB), etc. in a long-term evolution (LTE) system, a next-generation (mobile communication system) (next radio, NR) system or an authorized auxiliary access long-term evolution (LAA-LTE) system.

[0058] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system shown in Figure 1 as an example, the communication device may include a network device and a terminal device having a communication function. The network device and the terminal device may be specific devices in the embodiments of the present application and will not be described in detail here. The communication device may also include other devices in the communication system, such as a network controller, a mobility management entity, and other network entities, which are not limited in the embodiments of the present application.

[0059] It should be understood that the terms "system" and "network" are often used interchangeably herein. The term "and / or" is simply a description of an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " generally indicates that the related objects are in an "or" relationship.

[0060] It should be understood that the "indication" mentioned in the embodiments of this application can be a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" can mean that A directly indicates B, for example, B can be obtained through A; it can also mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; it can also mean that there is an association between A and B.

[0061] In the description of the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and being indicated, configuration and being configured, etc.

[0062] To facilitate understanding of the technical solutions of the embodiments of the present application, the relevant technologies of the embodiments of the present application are described below. The following relevant technologies can be arbitrarily combined with the technical solutions of the embodiments of the present application as optional solutions, and they all fall within the protection scope of the embodiments of the present application.

[0063] Random Access Response

[0064] The Random Access Response (RAR) window starts:

[0065] In response to a Physical Random Access Channel (PRACH) transmission, the User Equipment (UE) attempts to detect Downlink Control Information 1_0 (DCI 1_0) using a Cyclic Redundancy Check (CRC) scrambled with a Random Access Radio Network Temporary Identifier (RA-RNTI) within a higher-layer controlled RAR window. This window starts at the first symbol of the earliest Control Resource Set (CORESET) in the Common Search Space (CSS) set for the Type 1 Physical Downlink Control Channel (PDCCH) that the UE is configured to receive. This means that the window should be at least one symbol after the last symbol of the PRACH Occasion (RO) corresponding to the PRACH transmission. The window length is in slots, based on the subcarrier spacing of the Type 1 PDCCH CSS set, and is provided by the higher-layer parameter ra-ResponseWindow.

[0066] if or is not equal to 0, that is, considering the influence of the propagation delay of the non-terrestrial access network (NTN) system, the RAR window is TA +k mac ms (milliseconds) later. It is the timing advance (TA) calculated by the UE based on the UE position and satellite ephemeris. It is a public TA based on reference point and satellite ephemeris configuration, T TA Is considered and The total TA, k macThe round trip time (RTT) between the reference point and the base station needs to be covered, which can be provided by the high-level parameter K-Mac. As can be seen from Figure 2, T TA +k mac ms can cover the round-trip delay between the base station and the UE in the NTN system, and the corresponding RAR window startup timing is shown in Figure 3.

[0067] Received RAR message:

[0068] If the UE successfully receives a RAR message, that is, within the RAR window: 1) DCI 1_0 with CRC scrambled using RA-RNTI is detected, 2) and if DCI 1_0 includes the least significant bit (LSB) field of the system frame number (SFN) of the system radio frame, which is the same as the LSB of the SFN corresponding to the PRACH sent by the UE, 3) and the UE receives a transport block (TB) in the corresponding physical downlink shared channel (PDSCH), the UE passes the TB to the upper layer. The upper layer parses the TB to obtain the random access preamble identity (RAPID) associated with the PRACH transmission. If the upper layer recognizes the RAPID in the RAR message for the TB, it indicates an uplink grant to the physical layer, that is, the physical layer's random access response RAR uplink grant.

[0069] Regarding the Physical Uplink Shared Channel (PUSCH) transmission time slot of RAR uplink grant scheduling, if the UE receives the PDSCH carrying the RAR message in time slot n, the UE will receive the PDSCH in time slot n+k2+Δ+2 μ ·K cell,offet The PUSCH is sent, where the values ​​of k2 and Δ are provided by the existing protocol, K cell,offet Provided by high-level parameters, it is used to enforce timing relationships in NTN systems.

[0070] The UE may assume that the minimum time interval between the last symbol of the PDSCH carrying the RAR message with the RAR uplink (UL) grant and the first symbol of the RAR UL grant-scheduled PUSCH is equal to N T,1 +N T,2 +0.5ms, where N T,1 is the time length of N1 symbols corresponding to the PDSCH processing time, N T,2It is the time length of N2 symbols corresponding to the PUSCH preparation time.

[0071] RAR message not received:

[0072] If the UE does not successfully receive the RAR message, that is, within the RAR window: 1) DCI 1_0 with CRC scrambled using RA-RNTI is not detected, 2) or if DCI 1_0 includes the LSB field of SFN, but is different from the LSB of SFN corresponding to PRACH sent by the UE, 3) or the UE does not correctly receive the TB in the corresponding PDSCH, 4) or the upper layer does not recognize the RAPID associated with the PRACH transmission, then the upper layer can instruct the physical layer to send PRACH.

[0073] If the higher layer requests to send PRACH, the UE expects it to be sent no later than N after the last symbol of the RAR window or the last symbol of the PDSCH. T,1 +0.75ms to send PRACH, where N T,1 It is the time length corresponding to the PDSCH processing time.

[0074] PDSCH carrying contention resolution flag

[0075] When the UE is not provided with a cell radio network temporary identifier (Cell RNTI, C-RNTI), in response to a PUSCH transmission scheduled by an RAR UL grant, the UE attempts to detect DCI 1_0 with a CRC scrambled using a temporary cell radio network temporary identifier (Temporary Cell RNTI, TC-RNTI). The DCI1_0 schedules a PDSCH containing a UE contention resolution identifier. In response to the PDSCH containing the UE contention resolution identifier, the UE sends a Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) in the Physical Uplink Control Channel (PUCCH). The minimum time between the last symbol of the PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to N T,1 +0.75ms.

[0076] PDSCH repeated transmission scheme

[0077] When receiving a PDSCH scheduled with DCI 1_1 or 1_2 using a CRC scrambled with a C-RNTI, Modulation Coding Scheme Cell RNTI (MCS-C-RNTI), or Configured Scheduling RNTI (CS-RNTI), and if the UE is configured with the higher layer parameter pdsch-AggregationFactor = K, the same symbol allocation is used across K consecutive slots. The UE expects the TB to be repeated within each symbol allocation across each of the K consecutive slots, and the PDSCH is restricted to a single transmission layer.

[0078] For example, the redundancy version (RV) of the nth transmission opportunity of the TB is determined according to Table 1, where n=0, 1, ..., K-1

[0079] Table 1. RV applied when pdsch-AggregationFactor exists

[0080]

[0081] Related technical solutions do not support repeated PDSCH transmissions during the random access process, such as Msg2 PDSCH and Msg4 PDSCH. In coverage-constrained communication scenarios, such as NTN systems, a single PDSCH transmission may not meet coverage requirements. Especially during the initial access phase, failure to successfully receive the RAR message and UE contention resolution identifier carried by the PDSCH will prevent the UE from accessing the network, significantly impacting system performance. Therefore, enhancements to PDSCH transmission during the random access process are necessary, such as introducing a repeated PDSCH transmission scheme to improve coverage.

[0082] FIG4 is a schematic flow chart of a repeated transmission method 400 according to an embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents.

[0083] S410. The terminal device receives repeated transmission of a message during a random access process.

[0084] In one example, the messages in the four-step random access process may include: a PRACH (also referred to as message 1 or Msg1) sent by the terminal device to the network device, which may include a preamble code. A PDCCH and a PDSCH including a RAR message (also referred to as message 2 or Msg2) sent by the network device to the terminal device, which may be a PDSCH scheduled by DCI with RA-RNTI scrambled CRC. A PUSCH (also referred to as message 3 or Msg3) sent by the terminal device to the network device. A PDSCH and PDCCH (also referred to as message 4 or Msg4) sent by the network device to the terminal device, which may be a PDSCH scheduled by DCI with TC-RNTI scrambled CRC.

[0085] In one example, the messages in the two-step random access process may include: PRACH and PUSCH (also referred to as message A or MsgA) sent by the terminal device to the network device, where the PRACH may include a preamble. PDSCH and PDCCH (also referred to as message B or MsgB) sent by the network device to the terminal device, where the PDSCH may be a DCI-scheduled PDSCH using a MsgB-RNTI scrambled CRC.

[0086] In an embodiment of the present application, the terminal device may receive repeated transmissions of one or more messages in the random access process. The terminal device may also repeatedly send or repeatedly transmit one or more messages in the random access process to the network device.

[0087] In the embodiment of the present application, the success rate of random access can be improved based on repeated transmission of messages during the random access process.

[0088] In one embodiment, the terminal device receives repeated transmissions of a message in a random access process, including: the terminal device receives repeated transmissions of the PDSCH based on the number of repeated transmissions of the PDSCH.

[0089] For example, if the number of repeated transmissions of the PDSCH is 4, the terminal device receives 4 repeated transmissions of the PDSCH from the network device.

[0090] In one embodiment, the type of the PDSCH includes at least one of the following:

[0091] PDSCH scheduled by DCI using random access RA-RNTI scrambled CRC;

[0092] PDSCH scheduled by DCI using TC-RNTI scrambled CRC;

[0093] Use MsgB-RNTI to scramble the CRC of the DCI-scheduled PDSCH.

[0094] In one embodiment, the repeated transmission method further includes: the terminal device requests repeated transmission of the PDSCH. For example, after the terminal device requests repeated transmission of the PDSCH from the network device, the network device repeatedly transmits the PDSCH to the terminal device. The terminal device receives the repeated transmission of the PDSCH from the network device.

[0095] In one embodiment, the terminal device requests repeated transmission of the PDSCH, including at least one of the following:

[0096] The terminal device requests repeated transmission of the PDSCH according to a specific PRACH format;

[0097] The terminal device requests repeated transmission of the PDSCH according to the RO used to send the PRACH;

[0098] The terminal device requests repeated transmission of the PDSCH according to a specific PRACH preamble.

[0099] For example, if the terminal device uses a specific PRACH format to send PRACH, then after the network device receives the PRACH, it can determine that one or more PDSCHs in the random access process need to be repeatedly transmitted. For another example, if the terminal device sends PRACH on a specific RO, then after the network device receives the PRACH, it can determine that one or more PDSCHs in the random access process need to be repeatedly transmitted. For another example, if the terminal device sends a specific PRACH preamble, then after the network device receives the PRACH preamble (Preamble), it can determine that one or more PDSCHs in the random access process need to be repeatedly transmitted.

[0100] In one embodiment, the method for determining the number of repeated transmissions of the PDSCH includes one of the following:

[0101] The terminal device determines the number of repeated transmissions of the PDSCH according to the system message broadcast by the network device;

[0102] If the system message does not configure the number of repeated transmissions of the PDSCH, the terminal device determines the number of repeated transmissions of the PDSCH according to a default value;

[0103] The terminal device determines the number of repeated transmissions of the PDSCH based on N, where N is a positive integer.

[0104] In an embodiment of the present application, the number of repeated transmissions of a PDSCH can be broadcasted through a system message. After the terminal device requests repeated transmission of the PDSCH, the number of repeated transmissions of the PDSCH broadcasted by the received system message can be applied to receive repeated transmissions of the PDSCH. If the terminal device requests repeated transmission of the PDSCH, but there is no repeated transmission number of the PDSCH in the system message, the terminal device can receive repeated transmissions of the PDSCH based on a fixed value, that is, the default repeated transmission number of the PDSCH. The default repeated transmission number of the PDSCH can be a value specified or preset according to the protocol. Alternatively, regardless of whether the system message is received, the terminal device can determine the number of repeated transmissions of the PDSCH according to the value N specified or preset according to the protocol. For example, N can be 2, 4, 8, 16, etc., and N can be specifically designed based on the coverage performance requirements. For example, if the current PDSCH coverage performance is close to the coverage requirement, such as within 3dB, then N=2 can meet the coverage requirement; for another example, if the current PDSCH coverage performance is close to the coverage requirement, such as more than 10dB, then N=16 is required to meet the coverage requirement. The value N and the default number of repeated transmissions of the PDSCH may be the same or different.

[0105] In one embodiment, a method for determining the number of repeated transmissions of the PDSCH (which may be an implicit determination method) includes one of the following:

[0106] The terminal device determines the number of repetition transmissions of the PDSCH according to the number of repetition transmissions of the PRACH or the number of repetitions of the PRACH sequence;

[0107] The terminal device determines the number of repetitions of the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC according to the number of repetitions of the PUSCH sent in the random access process;

[0108] The terminal device determines the number of repeated transmissions of the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC based on the number of repeated transmissions of the PDSCH scheduled by the DCI using the RA-RNTI scrambled CRC.

[0109] For example, the terminal device and / or the network device can determine the number of repetitions of PDSCH (message 2) scheduled by DCI with RA-RNTI scrambled CRC, the number of repetitions of PDSCH (message 4) scheduled by DCI with TC-RNTI scrambled CRC, or the number of repetitions of PDSCH (message B) scheduled by DCI with MsgB-RNTI scrambled CRC based on the number of repetitions of PRACH (message 1 or message A) or the number of repetitions of PRACH sequence sent by the terminal device.

[0110] For another example, the terminal device and / or network device may determine the number of repetitions of PDSCH (message 4) scheduled by DCI using TC-RNTI scrambled CRC based on the number of repetitions of PUSCH (message 3) sent by the terminal device.

[0111] For another example, the terminal device and / or the network device determines the number of repeated transmissions of the PDSCH scheduled by DCI using TC-RNTI scrambled CRC (message 4) based on the number of repeated transmissions of the PDSCH scheduled by DCI using RA-RNTI scrambled CRC (message 2).

[0112] In one embodiment, if the terminal device requests repeated transmission of the PDSCH, but the system message does not include the number of repeated transmissions of the PDSCH, the terminal device may also determine the number of repeated transmissions of the PDSCH through the above-mentioned implicit determination method.

[0113] In one embodiment, the method for determining the number of repeated transmissions of the PDSCH includes one of the following:

[0114] The terminal device determines the number of repeated transmissions of the PDSCH according to a set of candidate values ​​of the number of repeated transmissions of the PDSCH in the system message broadcast by the network device;

[0115] In the case that the system message does not configure the set of candidate values ​​for the number of repeated transmissions of the PDSCH, the terminal device determines the number of repeated transmissions of the PDSCH according to the default set of candidate values ​​for the number of repeated transmissions of the PDSCH;

[0116] The terminal device determines the number of repetition transmissions of the PDSCH based on a set of M candidate values ​​of the number of repetition transmissions of the PDSCH, where M is a positive integer.

[0117] In an embodiment of the present application, if there are multiple optional values ​​in the set of candidate values ​​for the number of repeated transmissions of the PDSCH, the DCI can be used to dynamically indicate the specific value of the number of repeated transmissions of the PDSCH. For example, the number of repeated transmissions of multiple PDSCHs can be broadcast through a system message, and these multiple number of repeated transmissions of PDSCHs constitute a set of candidate values ​​for the number of repeated transmissions of the PDSCH. After the terminal device requests repeated transmission of the PDSCH, it can apply the received system message broadcast set of the number of repeated transmissions of the PDSCH, and determine a number of repeated transmissions of the PDSCH from the set of candidate values ​​for the number of repeated transmissions of the PDSCH based on the DCI to receive repeated transmissions of the PDSCH. If the terminal device requests PDSCH repeated transmission, but there is no set of candidate values ​​for the number of repeated transmissions of PDSCH in the system message, the terminal device can use a set of fixed values, i.e., the default set of candidate values ​​for the number of repeated transmissions of PDSCH, as the set of candidate values ​​for the number of repeated transmissions of PDSCH, and determine a PDSCH repeated transmission number from the set of candidate values ​​for the number of repeated transmissions of PDSCH based on DCI to receive repeated transmissions of PDSCH. The default set of candidate values ​​for the number of repeated transmissions of PDSCH can be a set of numerical values ​​specified in the protocol or preset.

[0118] Alternatively, regardless of whether a system message is received, the terminal device may determine the number of PDSCH repetition transmissions based on a protocol-specified or preset set of M candidate values ​​for the number of PDSCH repetition transmissions. For example, M may be 4. For example, the set of candidate values ​​may be {1, 2, 4, 8}. The number of candidate values ​​M and the number of default values ​​in the default value set may be the same or different.

[0119] In one embodiment, the number of repeated transmissions of the PDSCH is indicated by an information field in the DCI. In the embodiment of the present application, an existing field in the DCI is reused as the information field, or a new information field is added using reserved bits in the DCI.

[0120] In one embodiment, the information field is a modulation coding scheme (MCS) field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH. In an embodiment of the present application, the MCS field of the DCI can indicate both the MCS corresponding to the scheduled PDSCH and the number of repeated transmissions of the PDSCH. The multiplexing of the MCS field is only an example and not a limitation, and other fields in the DCI can also be multiplexed to indicate the number of repeated transmissions of the PDSCH.

[0121] In an embodiment of the present application, some bits of the MCS field of the DCI indicate the number of repeated transmissions of the PDSCH, and some bits indicate the MCS corresponding to the PDSCH. In one embodiment, the most significant bit (MSB) of the MCS field indicates the number of repeated transmissions of the PDSCH, and the least significant bit (LSB) of the MCS field indicates the MCS corresponding to the PDSCH. For example, the 2-bit MSB of the MCS field indicates the number of repeated transmissions of the PDSCH, and the 3-bit LSB of the MCS field indicates the MCS corresponding to the PDSCH.

[0122] In one embodiment, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the number of repeated transmissions of the PDSCH. For example, the 3-bit MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the 2-bit LSB of the MCS field indicates the number of repeated transmissions of the PDSCH.

[0123] In one embodiment, the LSB of the MCS domain indicates the MCS index applied in the MCS index candidate value set, or the MSB of the MCS domain indicates the MCS index applied in the MCS index candidate value set; wherein the MCS index candidate value set is configured by the network device through a system message; or, if the MCS index candidate value set is not configured, the default set is used as the MCS index candidate value set.

[0124] In an embodiment of the present application, if part of the bits of the MCS field are used to indicate the number of repeated transmissions of the PDSCH, the types of MCS corresponding to the PDSCH that can be indicated by the remaining bits of the MCS field will be reduced. In this case, the MCS index candidate value set can be configured through a system message (for example, high-level parameters can be broadcast through a system message), and the MCS index candidate value set includes a part, for example, 8 MCS index candidate values. Since the signal quality is generally weak in scenarios where PDSCH repeated transmission is required, usually only MCS indexes with lower code rates will be used, so indicating part of the MCS index candidate values ​​can also work normally. The terminal device can determine an MCS index from the MCS index candidate value set based on the indication of the MCS field. In addition, if the MCS index candidate value set is not configured in the system message, a set of fixed values, i.e., a default set, can be used as the MCS index candidate value set, and the terminal device can determine an MCS index from the default set based on the indication of the MCS field.

[0125] In one embodiment, the information field includes a repetition transmission number field, and the repetition transmission number field is used to indicate the repetition transmission number of the PDSCH.

[0126] In the embodiment of the present disclosure, a reserved bit in the DCI may be used to add an information field, and the information field may include a repeated transmission times field, or a field with other names.

[0127] In one embodiment, the repetition number field occupies reserved bits in the DCI.

[0128] In one embodiment, the repetition number field occupies reserved bits of a downlink assignment index (DAI) field of a DCI using a TC-RNTI scrambled CRC.

[0129] In one embodiment, the number of repeated transmissions of the PDSCH is K, and the terminal device receives the repeated transmissions of the PDSCH based on the number of repeated transmissions of the PDSCH, including:

[0130] The terminal device receives repeated transmissions of the PDSCH in K consecutive time slots;

[0131] The K consecutive time slots and the PDSCH have at least one of the following characteristics:

[0132] The PDSCH uses the same symbol allocation in the K consecutive time slots;

[0133] The terminal device repeatedly receives a TB in the PDSCH in each symbol allocation in each time slot of the K consecutive time slots;

[0134] The PDSCH is a single transmission layer.

[0135] In one embodiment, the redundancy version identifier corresponding to the first transmission opportunity of the repeated transmission of the PDSCH is determined based on at least one of the following:

[0136] The default value of the redundant version identifier;

[0137] The redundancy version field in the DCI indicates

[0138] In this embodiment of the present application, a redundancy version loop sequence may be set, for example, [0 2 3 1]. Based on this loop sequence, the first version number "0" may be used as the starting version number for the loop and used as the default value for the redundancy version identifier, and the loop sequence may be 0, 2, 3, and 1. Alternatively, the first version number, for example, "2," may be indicated by the redundancy version field in the DCI, and the loop sequence may be 2, 3, 1, and 0.

[0139] FIG5 is a schematic flow chart of a repeated transmission method 500 according to another embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents:

[0140] S510. The terminal device repeatedly transmits PRACH.

[0141] In the embodiment of the present application, the terminal device repeatedly transmitting PRACH can also be described as the terminal device repeatedly transmitting PRACH, or the terminal device repeatedly sending PRACH.

[0142] In one embodiment, the repeated transmission method 500 may be combined with the embodiments related to the repeated transmission method 400 described above. For details, please refer to the relevant description of method 400 and will not be repeated here. For example, after the terminal device repeatedly transmits the PRACH to the network device, the terminal device receives the repeated transmission of the PDSCH based on the number of repeated transmissions of the PDSCH.

[0143] In one embodiment, the method further includes: the terminal device determining a random access response (RAR) window based on the RO corresponding to the last PRACH repeated transmission. For example, the terminal device initiates a random access response (RAR) window based on the RO corresponding to the last PRACH repeated transmission. The terminal device can receive a RAR message in the RAR window.

[0144] In one embodiment, determining the position of the RAR window includes at least one of the following:

[0145] The terminal device determines the starting position of the RAR window according to the symbol after the last symbol of the RO corresponding to the last PRACH repeated transmission;

[0146] The terminal device determines the starting position of the RAR window based on the symbol after the last symbol of the RO corresponding to the repeated transmission of the last PRACH, and the first symbol of the earliest control resource set CORESET where the PDCCH of the common search space CSS set of the received type 1 physical downlink control channel Type1-PDCCH is located.

[0147] In one embodiment, the terminal device starts the RAR window at least one symbol after the last symbol of the RO corresponding to the last repeated transmission of the PRACH. For example, after the terminal device repeatedly transmits three PRACHs, the terminal device starts the RAR window at least one symbol after the last symbol of the RO corresponding to the third repeated transmission of the PRACH.

[0148] In one embodiment, the terminal device starts the RAR window at least one symbol after the last symbol of the RO corresponding to the last repeated transmission of the PRACH, and the first symbol of the earliest control resource set (CORESET) where the PDCCH of the Type 1 physical downlink control channel (Type1-PDCCH) common search space (CSS) set is received. For example, the terminal device starts the RAR window after repeatedly transmitting 3 PRACHs, at least one symbol after the last symbol of the RO corresponding to the last repeated transmission of the PRACH, and the first symbol of the earliest CORESET where the PDCCH of the Type 1-PDCCH CSS set is received.

[0149] In one embodiment, the terminal device starts the RAR window after a delay of at least one symbol after the last symbol of the RO corresponding to the last repeated transmission of the PRACH and the first symbol of the earliest CORESET where the PDCCH of the Type 1-PDCCH CSS set is located. The delay can represent the round-trip delay between the terminal device and the network device. For example, the delay is equal to T TA +k mac ms, among which, is the timing advance (TA) calculated by the UE based on the UE position and satellite ephemeris, It is a public TA based on reference point and satellite ephemeris configuration, T TA Is considered and The total TA, k mac The RTT between the reference point and the base station needs to be covered. For example, or Not equal to 0, that is, the above delay applies in the case of the NTN system.

[0150] In this embodiment of the present application, the requirement of "receiving a RAR message within the RAR window" can be relaxed to "receiving a DCI scrambled with a CRC using the RA-RNTI within the RAR window." For example, see the following description of successfully receiving a RAR message within the RAR window and / or failing to successfully receive a RAR message within the RAR window.

[0151] In one embodiment, successfully receiving a RAR message within the RAR window includes at least one of the following:

[0152] A DCI scrambled with CRC using RA-RNTI is detected within the RAR window;

[0153] In the case where a DCI using RA-RNTI scrambled CRC is detected within the RAR window, if the DCI includes the least significant bit (LSB) field of the system radio frame SFN, and the LSB field in the DCI is the same as the LSB of the SFN corresponding to the PRACH sent by the terminal device;

[0154] When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, the terminal device successfully receives the transport block TB in the PDSCH scheduled by the DCI;

[0155] The high-level TB of the terminal device obtains the RAPID associated with the PRACH transmission.

[0156] In one embodiment, failure to successfully receive the RAR message within the RAR window includes one of the following:

[0157] No DCI using RA-RNTI scrambled CRC is detected within the RAR window;

[0158] In the case where a DCI using RA-RNTI scrambled CRC is detected within the RAR window, if the DCI includes the LSB field of the SFN, but the LSB field in the DCI is different from the LSB of the SFN corresponding to the PRACH sent by the terminal device;

[0159] In the case where a DCI using RA-RNTI scrambled CRC is detected within the RAR window, the terminal device does not receive the TB in the PDSCH scheduled by the DCI;

[0160] The higher layer of the terminal device does not recognize the random access preamble identifier RAPID associated with the PRACH transmission.

[0161] The above-mentioned high layer and physical layer may be the high layer and physical layer in the terminal device.

[0162] In one embodiment, the maximum length of the RAR window that can be configured is adjusted from a first length to a second length, where the second length is greater than the first length;

[0163] The terminal device receives repeated transmission of a message during the random access process, including:

[0164] The terminal device receives the RAR message within a RAR window whose maximum length can be configured as the second length.

[0165] In one embodiment, the maximum length of the RAR window can be adjusted to a larger length. For example, the maximum length of the RAR window can be adjusted from a first length to a second length, where the second length is greater than the first length. For example, the maximum length of the RAR window can be adjusted from 10 ms to 20 ms, 30 ms, or 40 ms. The specific adjustment value can be set based on the requirements of the actual application scenario. The maximum length of the RAR window can be adjusted based on protocol specifications, network configuration, pre-configuration, etc.

[0166] In one embodiment, the method further includes: the terminal device determining a PUSCH transmission time slot for RAR uplink (UL) grant scheduling based on the received repeated transmission of the last PDSCH carrying the RAR message. For example, the network device repeatedly transmits two PDSCHs carrying RAR messages to the terminal device, namely, PDSCH#1 and PDSCH#2. The terminal device can determine the PUSCH transmission time slot for RAR UL grant scheduling based on the received repeated transmission of the second PDSCH, namely, PDSCH#2.

[0167] In one embodiment, the PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot n of the last repeated transmission of the PDSCH carrying the RAR message is received, and the first duration is determined based on the slot-level offset of the RAR UL grant to the PUSCH. For example, the first duration is equal to k2+Δ+2 μ ·K cell,offet Among them, the values ​​of k2 and Δ can be provided by the relevant protocol, K cell,offet It can be provided by high-level parameters and used to enhance the timing relationship in the NTN system. The terminal equipment is in time slot n+k2+Δ+2 μ ·K cell,offet Send the PUSCH.

[0168] In one embodiment, the minimum time interval between the last symbol of the last PDSCH retransmission carrying the RAR message with the RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time. For example, the minimum time interval is equal to N T,1 +N T,2 +0.5ms, where N T,1 is the time length of N1 symbols corresponding to the PDSCH processing time, N T,2 It is the time length of N2 symbols corresponding to the PUSCH preparation time.

[0169] In one embodiment, the method further includes: if the terminal device fails to successfully receive the RAR message, the upper layer instructs the physical layer to send the PRACH, then the terminal device expects to send the PRACH no later than a second duration after the last symbol of the last repeated transmission of the PDSCH; wherein the second duration is determined based on the PDSCH processing time. For example, the second duration is equal to N T,1 +0.75ms. Where N T,1 It is the time length of N1 symbols corresponding to the PDSCH processing time.

[0170] FIG6 is a schematic flow chart of a repeated transmission method 600 according to another embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents:

[0171] In one embodiment, the PUCCH transmission time slot is adjusted so that the minimum time interval between the last symbol of the last repeated transmission of the PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; wherein the third duration is determined based on the PDSCH processing time. For example, the third duration is equal to N T,1 +0.75ms. Where N T,1 It is the time length of N1 symbols corresponding to the PDSCH processing time.

[0172] In one embodiment, when the terminal device is not provided with a cell radio network temporary identifier (C-RNTI), the terminal device detects the DCI using the TC-RNTI scrambled CRC in response to the PUSCH transmission and receives the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC.

[0173] In one embodiment, the PDSCH scheduled by the DCI using the TC-RNTI to scramble the CRC is a PDSCH including a terminal device contention resolution identifier.

[0174] S610: In response to the PDSCH containing the terminal device contention resolution identifier, the terminal device sends a HARQ-ACK in the PUCCH.

[0175] In the embodiment of the present application, PUSCH transmission may also be PUSCH repeated transmission.

[0176] In one embodiment, the repeated transmission method 600 may be combined with the embodiments related to the repeated transmission method 400 and / or 500 described above. For details, please refer to the relevant description of the method 400 and / or 500, which will not be repeated here.

[0177] FIG7 is a schematic flow chart of a repeated transmission method 700 according to an embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents.

[0178] S710: The network device repeatedly transmits a message in the random access process.

[0179] In one embodiment, the network device repeatedly transmits a message in a random access process, including: the network device repeatedly transmits the PDSCH based on a number of repeated transmissions of the PDSCH.

[0180] In one embodiment, the type of the PDSCH includes at least one of the following:

[0181] The PDSCH scheduled by the downlink control information DCI is scrambled with the cyclic redundancy check CRC using the random access radio network temporary identifier RA-RNTI;

[0182] The DCI-scheduled PDSCH with the CRC scrambled using the temporary cell radio network temporary identifier TC-RNTI;

[0183] The DCI-scheduled PDSCH with CRC is scrambled using message B MsgB-RNTI.

[0184] In one embodiment, the method further includes: the network device receiving a request from the terminal device for repeated transmission of the PDSCH.

[0185] In one embodiment, the network device receiving the request from the terminal device for repeated transmission of the PDSCH includes at least one of the following:

[0186] The network device receives a request from the terminal device for repeated transmission of the PDSCH according to a specific PRACH format;

[0187] The network device receives, according to the RO used to send the PRACH, a request from the terminal device for repeated transmission of the PDSCH;

[0188] The network device receives the terminal device's request for repeated transmission of the PDSCH according to a specific PRACH preamble.

[0189] In one embodiment, the method for determining the number of repeated transmissions of the PDSCH includes one of the following:

[0190] The network device broadcasts the number of repeated transmissions of a PDSCH through a system message;

[0191] If the number of repeated transmissions of the PDSCH is not configured in the system message, the network device determines the number of repeated transmissions of the PDSCH according to a default value;

[0192] The number of repeated transmissions of the PDSCH is determined according to N, where N is a positive integer.

[0193] In one embodiment, the method for determining the number of repeated transmissions of the PDSCH includes one of the following:

[0194] The network device determines the number of repetitions of the PDSCH according to the number of repetitions of the PRACH or the number of repetitions of the PRACH sequence sent by the terminal device;

[0195] The network device determines the number of repetitions of the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC according to the number of repetitions of the PUSCH sent by the terminal device during the random access process;

[0196] The network device determines the number of repetition transmissions of the PDSCH scheduled by the DCI using the TC-RNTI to scramble the CRC according to the number of repetition transmissions of the PDSCH scheduled by the DCI using the RA-RNTI to scramble the CRC.

[0197] In one embodiment, the method for determining the number of repeated transmissions of the PDSCH includes one of the following:

[0198] The network device broadcasts a set of candidate values ​​of the number of repeated transmissions of the PDSCH through a system message;

[0199] In the case that the system message does not configure the set of candidate values ​​for the number of repeated transmissions of the PDSCH, the network device determines the number of repeated transmissions of the PDSCH according to the default set of candidate values ​​for the number of repeated transmissions of the PDSCH;

[0200] The network device determines the number of repetition transmissions of the PDSCH according to a set of M candidate values ​​of the number of repetition transmissions of the PDSCH, where M is a positive integer.

[0201] In one embodiment, the number of repeated transmissions of the PDSCH is indicated by an information field in the DCI.

[0202] In one implementation, the information field is an MCS field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH.

[0203] In one implementation, the MSB of the MCS field indicates the number of repeated transmissions of the PDSCH, and the LSB of the MCS field indicates the MCS corresponding to the PDSCH.

[0204] In one implementation, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the number of repeated transmissions of the PDSCH.

[0205] In one embodiment, the LSB of the MCS field indicates the MCS index applied in the MCS index candidate value set, or the MSB of the MCS field indicates the MCS index applied in the MCS index candidate value set;

[0206] The MCS index candidate value set is configured by the network device through a system message; or, when the MCS index candidate value set is not configured, a default set is used as the MCS index candidate value set.

[0207] In one embodiment, the information field includes a repetition transmission number field, and the repetition transmission number field is used to indicate the repetition transmission number of the PDSCH.

[0208] In one embodiment, the repetition number field occupies reserved bits in the DCI.

[0209] In one embodiment, the repetition number field occupies reserved bits of the downlink allocation index (DAI) field of the DCI using the TC-RNTI to scramble the CRC.

[0210] In an embodiment of the present application, the method for determining the number of repeated transmissions of the PDSCH adopted by the PDSCH of Msg2 (PDSCH scheduled by DCI using RA-RNTI scrambled CRC), the PDSCH of Msg4 (PDSCH scheduled by DCI using TC-RNTI scrambled CRC), and the PDSCH of MsgB (PDSCH scheduled by DCI using MsgB-RNTI scrambled CRC) may be the same or different. Specifically, any one or more of the above-mentioned methods for determining the number of repeated transmissions of the PDSCH in the embodiment of the present application may be used according to the actual application scenario.

[0211] In one embodiment, the number of repeated transmissions of the PDSCH is K, and the network device repeatedly transmits the PDSCH based on the number of repeated transmissions of the PDSCH, including:

[0212] The network device repeatedly transmits the PDSCH in K consecutive time slots;

[0213] The K consecutive time slots and the PDSCH have at least one of the following characteristics:

[0214] The PDSCH uses the same symbol allocation in the K consecutive time slots;

[0215] Repeatedly transmitting the TB in the PDSCH in each symbol allocation in each time slot in the K consecutive time slots;

[0216] The PDSCH is a single transmission layer.

[0217] In one embodiment, the redundancy version identifier corresponding to the first transmission opportunity of the repeated transmission of the PDSCH is determined based on at least one of the following:

[0218] The default value of the redundant version identifier;

[0219] The redundancy version field in the DCI indicates

[0220] FIG8 is a schematic flow chart of a repeated transmission method 800 according to an embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents:

[0221] S810: The network device receives repeated transmissions of PRACH.

[0222] In one embodiment, the retransmission method 800 may be combined with the embodiments related to the retransmission method 700 described above. For details, please refer to the relevant description of the method 700, which is not repeated here. For example, after the network device receives the PRACH repeatedly transmitted by the terminal device, the network device repeatedly transmits the PDSCH based on the number of retransmissions of the PDSCH.

[0223] In one implementation, the network device repeatedly transmitting a message in the random access process includes: the network device sending a RAR message based on the repeated transmission of the last PRACH.

[0224] In one embodiment, the maximum length of the RAR window that can be configured is adjusted from a first length to a second length, where the second length is greater than the first length.

[0225] FIG9 is a schematic flow chart of a repeated transmission method 900 according to an embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents:

[0226] S910: The network device receives a PUSCH scheduled by an RAR UL grant, where a transmission time slot of the PUSCH scheduled by the RAR UL grant is determined by the terminal device based on repeated transmission of the last PDSCH carrying an RAR message received.

[0227] In one embodiment, the repeated transmission method 900 may be combined with the embodiments related to the repeated transmission method 700 and / or 800 described above. For details, please refer to the relevant descriptions of the methods 700 and / or 800, which will not be repeated here.

[0228] In one embodiment, the PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot of the last repeated transmission of the PDSCH carrying the RAR message is received, where the first duration is determined based on the time slot offset from the RAR UL grant to the PUSCH.

[0229] In one embodiment, the minimum time interval between the last symbol of the last PDSCH repeated transmission carrying the RAR message with the RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time.

[0230] In one embodiment, a network device receives repeated transmissions of a PRACH, including: the network device receives the PRACH sent by the terminal device when the RAR message is not successfully received; wherein the terminal device expects to send the PRACH no later than a second time duration after the last symbol of the repeated transmission of the last PDSCH; wherein the second time duration is determined based on the PDSCH processing time.

[0231] In one embodiment, the PDSCH scheduled by the DCI using the TC-RNTI to scramble the CRC is a PDSCH including a terminal device contention resolution identifier.

[0232] In one implementation, the network device receiving the PUSCH scheduled by the RAR UL grant includes: the network device receiving the HARQ-ACK carried in the PUCCH.

[0233] In one embodiment, the PUCCH transmission time slot is adjusted so that the minimum time interval between the last symbol of the repeated transmission of the last PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; wherein the third duration is determined based on the PDSCH processing time.

[0234] For specific examples of the terminal device network device execution methods 700, 800, and 900 of this embodiment, please refer to the relevant descriptions of network devices such as base stations in the above methods 400, 500, and 600. For the sake of brevity, they are not repeated here.

[0235] FIG10 is a schematic block diagram of a terminal device 1000 according to an embodiment of the present application. The terminal device 1000 may include:

[0236] The receiving unit 1010 is configured to receive repeated transmissions of messages in a random access process.

[0237] In one embodiment, the receiving unit 1010 is further configured to receive the repeated transmission of the PDSCH based on the number of repeated transmissions of the PDSCH.

[0238] In one embodiment, the type of the PDSCH includes at least one of the following:

[0239] PDSCH scheduled by DCI using RA-RNTI scrambled CRC;

[0240] PDSCH scheduled by DCI using TC-RNTI scrambled CRC;

[0241] The DCI-scheduled PDSCH with CRC is scrambled using message B MsgB-RNTI.

[0242] In one embodiment, as shown in FIG11 , the terminal device further includes:

[0243] The requesting unit 1110 is configured to request repeated transmission of the PDSCH.

[0244] In one embodiment, the request unit 1110 is configured to perform at least one of the following:

[0245] Request repeated transmission of the PDSCH according to a specific PRACH format;

[0246] Requesting repeated transmission of the PDSCH according to the RO used to send the PRACH;

[0247] The repeated transmission of the PDSCH is requested according to a specific PRACH preamble.

[0248] In one embodiment, the terminal device further includes a first processing unit 1130, and the first processing unit 1130 determines the number of repeated transmissions of the PDSCH in one of the following ways:

[0249] Determine the number of repetitions of the PDSCH according to the system message broadcast by the network device;

[0250] If the number of repeated transmissions of the PDSCH is not configured in the system message, the number of repeated transmissions of the PDSCH is determined according to the default value;

[0251] The number of repeated transmissions of the PDSCH is determined according to N, where N is a positive integer.

[0252] In one embodiment, the terminal device further includes a second processing unit 1140, and the second processing unit 1140 determines the number of repeated transmissions of the PDSCH in one of the following ways:

[0253] Determine the number of repetitions of the PDSCH according to the number of repetitions of the PRACH or the number of repetitions of the PRACH sequence;

[0254] Determine the number of repetitions of the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC according to the number of repetitions of the PUSCH sent during the random access procedure;

[0255] The number of repetition transmissions of the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC is determined according to the number of repetition transmissions of the PDSCH scheduled by the DCI using the RA-RNTI scrambled CRC.

[0256] In one embodiment, the terminal device further includes a third processing unit 1150, and the third processing unit 1150 determines the number of repeated transmissions of the PDSCH in one of the following ways:

[0257] Determine the number of repetition transmissions of the PDSCH according to a set of candidate values ​​of the number of repetition transmissions of the PDSCH in the system message broadcast by the network device;

[0258] If the system message does not configure a set of candidate values ​​for the number of repeated transmissions of the PDSCH, the number of repeated transmissions of the PDSCH is determined according to a default set of candidate values ​​for the number of repeated transmissions of the PDSCH;

[0259] The number of repetition transmissions of the PDSCH is determined according to a set of M candidate values ​​of the number of repetition transmissions of the PDSCH, where M is a positive integer.

[0260] In one embodiment, the number of repeated transmissions of the PDSCH is indicated by an information field in the DCI.

[0261] In one implementation, the information field is an MCS field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH.

[0262] In one embodiment, the most significant bit (MSB) of the MCS field indicates the number of repeated transmissions of the PDSCH, and the LSB of the MCS field indicates the MCS corresponding to the PDSCH.

[0263] In one implementation, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the number of repeated transmissions of the PDSCH.

[0264] In one embodiment, the LSB of the MCS field indicates the MCS index applied in the MCS index candidate value set, or the MSB of the MCS field indicates the MCS index applied in the MCS index candidate value set;

[0265] The MCS index candidate value set is configured by the network device through a system message; or, when the MCS index candidate value set is not configured, a default set is used as the MCS index candidate value set.

[0266] In one embodiment, the information field includes a repetition transmission number field, and the repetition transmission number field is used to indicate the repetition transmission number of the PDSCH.

[0267] In one embodiment, the repetition number field occupies reserved bits in the DCI.

[0268] In one embodiment, the repetition number field occupies reserved bits of the downlink allocation index (DAI) field of the DCI using the TC-RNTI to scramble the CRC.

[0269] In one embodiment, the number of repeated transmissions of the PDSCH is K, and the terminal device receives the repeated transmissions of the PDSCH based on the number of repeated transmissions of the PDSCH, including:

[0270] The terminal device receives repeated transmissions of the PDSCH in K consecutive time slots;

[0271] The K consecutive time slots and the PDSCH have at least one of the following characteristics:

[0272] The PDSCH uses the same symbol allocation in the K consecutive time slots;

[0273] The terminal device repeatedly receives a TB in the PDSCH in each symbol allocation in each time slot of the K consecutive time slots;

[0274] The PDSCH is a single transmission layer.

[0275] In one embodiment, the redundancy version identifier corresponding to the first transmission opportunity of the repeated transmission of the PDSCH is determined based on at least one of the following:

[0276] The default value of the redundant version identifier;

[0277] The redundancy version field in the DCI indicates

[0278] In one embodiment, as shown in FIG11 , the terminal device further includes:

[0279] The first sending unit 1120 is configured to repeatedly transmit the PRACH.

[0280] In one embodiment, as shown in FIG11 , the terminal device further includes:

[0281] The fourth processing unit 1160 is configured to determine the RAR window based on the RO corresponding to the last repeated transmission of the PRACH.

[0282] In one embodiment, the fourth processing unit 1160 determines the position of the RAR window by at least one of the following:

[0283] The starting position of the RAR window is determined according to the symbol after the last symbol of the RO corresponding to the repeated transmission of the last PRACH;

[0284] The starting position of the RAR window is determined according to the symbol after the last symbol of the RO corresponding to the repeated transmission of the last PRACH and the first symbol of the earliest control resource set CORESET where the PDCCH of the common search space CSS set of the receiving type 1 physical downlink control channel Type1-PDCCH is located.

[0285] In one embodiment, the symbol following the last symbol of the RO corresponding to the last repeated transmission of the PRACH may include at least one symbol following the last symbol of the RO corresponding to the last repeated transmission of the PRACH.

[0286] In one embodiment, successfully receiving a RAR message within the RAR window includes at least one of the following:

[0287] A DCI scrambled with CRC using RA-RNTI is detected within the RAR window;

[0288] In the case where a DCI using RA-RNTI scrambled CRC is detected within the RAR window, if the DCI includes the least significant bit (LSB) of the system radio frame SFN, and the LSB in the DCI is the same as the LSB of the SFN corresponding to the PRACH sent by the terminal device;

[0289] When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, the terminal device successfully receives the transport block TB in the PDSCH scheduled by the DCI;

[0290] The high-level TB of the terminal device obtains the RAPID associated with the PRACH transmission.

[0291] In one embodiment, failure to successfully receive the RAR message within the RAR window includes one of the following:

[0292] No DCI using RA-RNTI scrambled CRC is detected within the RAR window;

[0293] In the case where a DCI using RA-RNTI scrambled CRC is detected within the RAR window, if the DCI includes the LSB field of the SFN, but the LSB field in the DCI is different from the LSB of the SFN corresponding to the PRACH sent by the terminal device;

[0294] In the case where a DCI using RA-RNTI scrambled CRC is detected within the RAR window, the terminal device does not receive the TB in the PDSCH scheduled by the DCI;

[0295] The higher layer of the terminal device does not recognize the random access preamble identifier RAPID associated with the PRACH transmission.

[0296] In one embodiment, the maximum length of the RAR window that can be configured is adjusted from a first length to a second length, where the second length is greater than the first length;

[0297] The receiving unit is further configured to receive a RAR message within a RAR window whose maximum length can be configured as the second length.

[0298] For example, the maximum length of the RAR window is adjusted from a first length to a second length, where the second length is greater than the first length.

[0299] In one embodiment, as shown in FIG11 , the terminal device further includes:

[0300] The fifth processing unit 1170 is configured to determine a PUSCH transmission time slot scheduled by the RAR uplink UL grant based on the received repeated transmission of the last PDSCH carrying the RAR message.

[0301] In one embodiment, the PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot of the last repeated transmission of the PDSCH carrying the RAR message is received, where the first duration is determined based on the time slot offset from the RAR UL grant to the PUSCH.

[0302] In one embodiment, the minimum time interval between the last symbol of the last PDSCH repeated transmission carrying the RAR message with the RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time.

[0303] In one embodiment, as shown in FIG11 , the terminal device further includes:

[0304] The second sending unit 1190 is used to instruct the upper layer to send PRACH to the physical layer when the RAR message is not successfully received. The terminal device expects to send the PRACH no later than the second time length after the last symbol of the repeated transmission of the last PDSCH; wherein the second time length is determined based on the PDSCH processing time.

[0305] In one embodiment, the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC is a PDSCH including a terminal device contention resolution identifier, as shown in FIG11 , and the terminal device further includes:

[0306] The third sending unit 1191 is configured to send a HARQ-ACK in a PUCCH in response to the PDSCH containing the terminal device contention resolution identifier;

[0307] The PUCCH transmission time slot is adjusted so that the minimum time interval between the last symbol of the repeated transmission of the last PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; wherein the third duration is determined based on the PDSCH processing time.

[0308] The terminal device 1100 of the embodiment of the present application can implement the corresponding functions of the terminal device in the aforementioned method embodiment. The processes, functions, implementation methods and beneficial effects corresponding to the various modules (sub-modules, units or components, etc.) in the terminal device 1100 can be found in the corresponding descriptions in the above-mentioned method embodiments, which will not be repeated here. It should be noted that the functions described in the various modules (sub-modules, units or components, etc.) in the terminal device 1100 of the embodiment of the application can be implemented by different modules (sub-modules, units or components, etc.) or by the same module (sub-module, unit or component, etc.).

[0309] FIG12 is a schematic block diagram of a network device 1200 according to an embodiment of the present application. The network device 1200 may include:

[0310] The sending unit 1210 is configured to repeatedly transmit a message in a random access process.

[0311] In one embodiment, the sending unit 1210 is further configured to repeatedly transmit the physical downlink shared channel PDSCH based on a number of repeated transmissions of the PDSCH.

[0312] In one embodiment, the type of the PDSCH includes at least one of the following:

[0313] The PDSCH scheduled by the downlink control information DCI is scrambled with the cyclic redundancy check CRC using the random access radio network temporary identifier RA-RNTI;

[0314] The DCI-scheduled PDSCH with the CRC scrambled using the temporary cell radio network temporary identifier TC-RNTI;

[0315] The DCI-scheduled PDSCH with CRC is scrambled using message B MsgB-RNTI.

[0316] In one embodiment, as shown in FIG13 , the network device further includes:

[0317] The first receiving unit 1310 is configured to receive a request from a terminal device for repeated transmission of the PDSCH.

[0318] In one embodiment, the first receiving unit 1310 is further configured to perform at least one of the following:

[0319] receiving a request from the terminal device for repeated transmission of the PDSCH according to a specific PRACH format;

[0320] receiving, according to the RO used to send the PRACH, a request by the terminal device for repeated transmission of the PDSCH;

[0321] The terminal device receives a request for repeated transmission of the PDSCH according to a specific PRACH preamble.

[0322] In one embodiment, the network device further includes a first processing unit 1350, and the first processing unit 1350 determines the number of repeated transmissions of the PDSCH in one of the following ways:

[0323] The number of repetitions of a PDSCH is broadcasted via system messages;

[0324] If the number of repeated transmissions of the PDSCH is not configured in the system message, the number of repeated transmissions of the PDSCH is determined according to the default value;

[0325] The number of repeated transmissions of the PDSCH is determined according to N, where N is a positive integer.

[0326] In one embodiment, the network device further includes a second processing unit 1360, and the second processing unit 1360 determines the number of repeated transmissions of the PDSCH in one of the following ways:

[0327] Determine the number of repetitions of the PDSCH according to the number of repetitions of the PRACH or the number of repetitions of the PRACH sequence sent by the terminal device;

[0328] Determine the number of repetitions of the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC according to the number of repetitions of the physical uplink shared channel PUSCH sent by the terminal device during the random access process;

[0329] The number of repetition transmissions of the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC is determined according to the number of repetition transmissions of the PDSCH scheduled by the DCI using the RA-RNTI scrambled CRC.

[0330] In one embodiment, the network device further includes a third processing unit 1370, and the third processing unit 1370 determines the number of repeated transmissions of the PDSCH in one of the following ways:

[0331] Broadcast a set of candidate values ​​of the number of repetition transmissions of PDSCH through system messages;

[0332] If the system message does not configure a set of candidate values ​​for the number of repeated transmissions of the PDSCH, the number of repeated transmissions of the PDSCH is determined according to a default set of candidate values ​​for the number of repeated transmissions of the PDSCH;

[0333] The number of repetition transmissions of the PDSCH is determined according to a set of M candidate values ​​of the number of repetition transmissions of the PDSCH, where M is a positive integer.

[0334] In one embodiment, the number of repeated transmissions of the PDSCH is indicated by an information field in the DCI.

[0335] In one implementation, the information field is an MCS field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH.

[0336] In one implementation, the MSB of the MCS field indicates the number of repeated transmissions of the PDSCH, and the LSB of the MCS field indicates the MCS corresponding to the PDSCH.

[0337] In one implementation, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the number of repeated transmissions of the PDSCH.

[0338] In one embodiment, the LSB of the MCS field indicates the MCS index applied in the MCS index candidate value set, or the MSB of the MCS field indicates the MCS index applied in the MCS index candidate value set;

[0339] The MCS index candidate value set is configured by the network device through a system message; or, when the MCS index candidate value set is not configured, a default set is used as the MCS index candidate value set.

[0340] In one embodiment, the information field includes a repetition transmission number field, and the repetition transmission number field is used to indicate the repetition transmission number of the PDSCH.

[0341] In one embodiment, the repetition number field occupies reserved bits in the DCI.

[0342] In one embodiment, the repetition number field occupies reserved bits of the downlink allocation index (DAI) field of the DCI using the TC-RNTI to scramble the CRC.

[0343] In one embodiment, the number of repeated transmissions of the PDSCH is K, and the transmitting unit is further configured to repeatedly transmit the PDSCH in K consecutive time slots;

[0344] The K consecutive time slots and the PDSCH have at least one of the following characteristics:

[0345] The PDSCH uses the same symbol allocation in the K consecutive time slots;

[0346] Repeatedly transmitting the TB in the PDSCH in each symbol allocation in each time slot in the K consecutive time slots;

[0347] The PDSCH is a single transmission layer.

[0348] In one embodiment, the redundancy version identifier corresponding to the first transmission opportunity of the repeated transmission of the PDSCH is determined based on at least one of the following:

[0349] The default value of the redundant version identifier;

[0350] The redundancy version field in the DCI indicates

[0351] In one embodiment, as shown in FIG13 , the network device further includes:

[0352] The second receiving unit 1320 is configured to receive repeated transmissions of the PRACH.

[0353] In one implementation, the sending unit 1210 is configured to send the RAR message based on the last repeated transmission of the PRACH.

[0354] In one embodiment, the maximum length of the RAR window that can be configured is adjusted from a first length to a second length, where the second length is greater than the first length.

[0355] In one embodiment, as shown in FIG13 , the network device further includes:

[0356] The third receiving unit 1330 is configured to receive a PUSCH scheduled by an RAR UL grant, where a transmission time slot of the PUSCH scheduled by the RAR UL grant is determined by the terminal device based on repeated transmission of the last PDSCH carrying an RAR message received.

[0357] In one embodiment, the PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot of the last repeated transmission of the PDSCH carrying the RAR message is received, where the first duration is determined based on the time slot offset from the RAR UL grant to the PUSCH.

[0358] In one embodiment, the minimum time interval between the last symbol of the last PDSCH repeated transmission carrying the RAR message with the RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time.

[0359] In one embodiment, the sending unit 1210 is used to receive the PRACH sent by the terminal device when the RAR message is not successfully received; wherein, the terminal device expects to send the PRACH no later than a second time length after the last symbol of the repeated transmission of the last PDSCH; wherein, the second time length is determined based on the PDSCH processing time.

[0360] In one embodiment, the PDSCH scheduled by the DCI using the TC-RNTI scrambled CRC is a PDSCH including a terminal device contention resolution identifier, as shown in FIG13 , and the network device further includes:

[0361] The fourth receiving unit 1340 is configured to receive the HARQ-ACK carried in the PUCCH;

[0362] The PUCCH transmission time slot is adjusted so that the minimum time interval between the last symbol of the repeated transmission of the last PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; wherein the third duration is determined based on the PDSCH processing time.

[0363] The network device 1200 of the embodiment of the present application can implement the corresponding functions of the network device in the aforementioned method embodiment. The processes, functions, implementation methods and beneficial effects corresponding to each module (sub-module, unit or component, etc.) in the network device 1200 can be found in the corresponding description in the above method embodiment, and will not be repeated here. It should be noted that the functions described in the various modules (sub-module, unit or component, etc.) in the network device 1200 of the embodiment of the application can be implemented by different modules (sub-module, unit or component, etc.) or by the same module (sub-module, unit or component, etc.).

[0364] The repetition transmission method provided in the embodiment of the present application may include a random access process PDSCH repetition transmission scheme. In this scheme, the method for determining the number of repetition transmissions of PDSCH may include the following examples: (1) the system message broadcasts the number of repetition transmissions of one PDSCH; (2) the system message broadcasts the number of repetition transmissions of multiple PDSCHs; (3) the protocol specifies the candidate value of the number of repetition transmissions of PDSCH; (4) the number of repetition transmissions of PDSCH is implicitly determined. For the indication of the number of repetition transmissions of PDSCH in (2) and (3) above, the existing field in DCI can be reinterpreted, or the field of the number of repetition transmissions of PDSCH can be introduced.

[0365] For the reception of repeated Msg2 PDSCH transmissions, the RAR window can be started based on the RO corresponding to the last repeated PRACH transmission. (1) DCI 1_0 with CRC scrambled by RA-RNTI can be received within the RAR window. (2) The RAR window length can be extended to receive Msg2 PDSCH within the RAR window. The Msg3 PUSCH or PRACH transmission timing can be determined based on the last repeated Msg2 PDSCH transmission.

[0366] For the reception of Msg4 PDSCH repeated transmissions, the PUCCH transmission timing may be determined based on the last Msg4 PDSCH repeated transmission.

[0367] Example 1: RAR window launch

[0368] In related technologies, after a UE sends a PRACH, it can attempt to detect DCI 1_0 (i.e., Msg2 PDCCH) with RA-RNTI scrambled CRC within the RAR window controlled by higher layers in order to respond to the PRACH transmission. This DCI 1_0 schedules Msg2 PDSCH carrying the RAR message.

[0369] For scenarios where coverage enhancement is not required, the UE may select an RO to send the PRACH, and the start timing of the RAR window is consistent with the related art.

[0370] For scenarios requiring coverage enhancement, such as NTN systems, if the UE chooses to perform PRACH retransmissions on multiple ROs to improve coverage performance, the RAR window starts at least one symbol after the UE is configured to receive the last symbol of the RO corresponding to the last PRACH retransmission and the first symbol of the earliest CORESET where the PDCCH of the Type1-PDCCH CSS set is located. Similarly, considering the impact of the propagation delay of the NTN system, the RAR window needs to be set in the additional T TA +k mac Start after ms.

[0371] Taking Figure 14 as an example, in the NTN system, the UE performs PRACH retransmission on 4 ROs. The UE has an additional delay of T after the last symbol of the last RO. TA +k mac ms, the RAR window is started at the first symbol of the earliest CORESET where the PDCCH of the Type1-PDCCH CSS set is configured to be received.

[0372] Example 2: PDSCH repetition transmission scheme during random access process

[0373] Consider introducing a PDSCH retransmission scheme during random access to improve coverage performance. Specific examples are as follows:

[0374] The UE can decide whether to request PDSCH retransmissions from the base station based on the current coverage and whether it has the ability to receive PDSCH retransmissions. The UE can implicitly request PDSCH retransmissions through a specified random access resource. For example, as shown in Figure 15, the UE implicitly requests PDSCH retransmissions from the base station by using a specified PRACH format, sending PRACH on a specified RO, or sending a specified PRACH preamble. The UE can then receive the PDSCH retransmissions.

[0375] The following design schemes are available for determining the number of repeated transmissions K of the PDSCH:

[0376] Solution 1: System message broadcasts the number of repetitions of a PDSCH

[0377] The system message broadcasts a PDSCH retransmission count K. After the UE requests PDSCH retransmission, the PDSCH retransmission count broadcast by the system message can be applied. If the system message does not configure the PDSCH retransmission count, a fixed value, such as 4, is provided as the default value of the broadcast PDSCH retransmission count K.

[0378] Solution 2: System message broadcasting multiple PDSCH repetition times

[0379] System messages broadcast multiple PDSCH retransmission counts K = {K1, K2, ...}. If a UE requests PDSCH retransmission, the set of candidate PDSCH retransmission counts K = {K1, K2, ...} broadcast in the system message can be applied. If the system message does not configure PDSCH retransmission counts, a fixed set of PDSCH retransmission counts, such as the set K = {K1 = 1, K2 = 2, K3 = 3, K4 = 4}, is provided as the default value set for the broadcast PDSCH retransmission counts, as shown in Table 2.

[0380] Table 2. Number of repeated transmissions of PDSCH

[0381] Set of candidate values ​​for the number of repetition transmissions of the PDSCH configured Set of candidate values ​​for the number of repetition transmissions of the PDSCH not configured The first value of the number of repetition transmissions of the broadcasted PDSCH 1 The second value of the number of repetition transmissions of the broadcasted PDSCH 2 The third value of the number of repetition transmissions of the broadcasted PDSCH 3 The fourth value of the number of repetition transmissions of the broadcasted PDSCH 4

[0382] Solution 3: The protocol specifies candidate values ​​for the number of PDSCH retransmissions

[0383] The protocol specifies a set of candidate values ​​for the number of repeated transmissions of the PDSCH, that is, a set of candidate values ​​for the number of repeated transmissions of the PDSCH {K1, K2, ...}, for example, {K1 = 1, K2 = 2, K3 = 4, K4 = 8}. After the UE requests repeated transmission of the PDSCH, the introduced set of candidate values ​​for the number of repeated transmissions of the PDSCH {K1, K2, ...} can be applied.

[0384] Solution 4: Implicitly determine the number of repeated transmissions of PDSCH

[0385] The number of Msg2 PDSCH and Msg4 PDSCH retransmissions is associated with the number of retransmissions of other channels, implicitly determining the number of PDSCH retransmissions. For example, if Msg2 PDSCH and Msg4 PDSCH transmissions occur after PRACH transmissions, and if the number of PRACH retransmissions or PRACH sequence repetitions sent by the UE is N, then the number of Msg2 PDSCH (Msg4 PDSCH) retransmissions K (K') can be related to N, for example, K (K') = N / P, where P is a scaling factor, for example, P = 2.

[0386] Similarly, Msg4 PDSCH transmission occurs after Msg3 PUSCH transmission. If the number of repeated transmissions of Msg3 PUSCH is N, the number of repeated transmissions of Msg4 PDSCH K may have a certain relationship with N, such as K=N / P, where P is a scaling factor, such as P=2.

[0387] For schemes 2 and 3, since multiple PDSCH retransmission times are configured, it is necessary to further indicate the final applied value through DCI 1_0. Considering that there is no field for indicating the number of PDSCH retransmission times in the current DCI 1_0, at least one of the following schemes can be used to indicate the number of PDSCH retransmission times:

[0388] (1) Reinterpret the existing field in DCI 1_0 to indicate the number of repeated transmissions of the PDSCH. For example, the 5-bit MCS field in DCI 1_0 can be reinterpreted to indicate both the MCS corresponding to the PDSCH scheduled by DCI 1_0 and the number of repeated transmissions of the PDSCH.

[0389] For example, after the UE requests PDSCH retransmission, it first determines candidate values ​​for the number of PDSCH retransmissions, such as {K1=1, K2=2, K3=4, K4=8}. It then further indicates the number of PDSCH retransmissions to be applied using the two most significant bits (MSBs) of the MCS field in DCI 1_0, such as 00 indicating the first value K1, 01 indicating the second value K2, 10 indicating the third value K3, and 11 indicating the fourth value K4. This is shown in Table 3.

[0390] Table 3. The 2MSBs of the MCS field in DCI 1_0 indicate the number of repeated transmissions

[0391] MCS field 2MSBs repeated transmission times 001012104118

[0392] At the same time, the UE determines the MCS corresponding to the PDSCH through the 3 least significant bits (LSBs) of the MCS field in DCI 1_0. Considering that the original 5-bit MCS field can indicate MCS indexes 0-28, and the 3LSBs indicate a maximum of 8 MCS indexes, the base station needs to configure the MCS index candidate value set MCS = {MCS1,…,MCS7} through high-level parameters, and then the 3LSBs of the MCS field in DCI 1_0 indicate the MCS index of the specific application from the MCS index candidate value set MCS. It should be noted that if the MCS index candidate value set MCS is not configured, a fixed MCS index candidate value set is provided, such as the set MCS′ = {MCS′1 = 0,…,MCS′7 = 7} as the default set of MCS index candidate values. As shown in Table 4.

[0393] Table 4. The 3LSBs of the MCS field in DCI 1_0 indicate the MCS index

[0394]

[0395]

[0396] (2) Introduce a retransmission count field in DCI 1_0 to indicate the number of retransmissions of the PDSCH. Taking DCI 1_0 using TC-RNTI to scramble CRC as an example, its current downlink allocation index (DAI) field is a 2-bit reserved bit, which can be used to introduce a retransmission count field to indicate the number of retransmissions of the PDSCH. That is, if the UE requests PDSCH retransmission, the DAI field is 0 bits, and the retransmission count field is 2 bits to indicate the number of retransmissions of the PDSCH; if the UE does not request PDSCH retransmission, the DAI field is still a 2-bit reserved bit, and the retransmission count field is 0 bits. Similarly, the reserved bits in DCI 1_0 using RA-RNTI to scramble CRC can also be used to introduce a retransmission count field.

[0397] For example, after the UE requests PDSCH retransmission, it first determines the retransmission count set {K1=1, K2=2, K3=4, K4=8} through scheme 2 or 3. It then indicates the applied PDSCH retransmission count through the retransmission count field introduced in DCI 1_0, such as 00 indicating the first value K1, 01 indicating the second value K2, 10 indicating the third value K3, and 11 indicating the fourth value K4. Table 5 shows this.

[0398] Table 5. PDSCH retransmission times corresponding to the retransmission times field

[0399]

[0400] Based on the above scheme, the UE can determine the number of PDSCH repetitions K and receive the corresponding PDSCH repetitions. PDSCH uses the same symbol allocation in K consecutive time slots. The UE expects the TB to be repeated within each symbol allocation in each time slot of the K consecutive time slots, and the PDSCH is restricted to a single transmission layer.

[0401] For the determination of the redundancy version, if the RV field does not exist in DCI 1_0, for example, DCI 1_0 using RA-RNTI to scramble CRC, then for the repeated transmission of PDSCH scheduled by DCI 1_0, such as Msg2 PDSCH, the redundancy version rvid applied to the nth transmission opportunity of the TB is determined according to the first row in Table 1, that is, rvid = 0 for the first transmission opportunity, and is based on the [0 2 3 1] cycle, where n = 0, 1, ..., K-1.

[0402] If the RV field exists in DCI 1_0, for example, DCI 1_0 with TC-RNTI scrambled CRC, then for repeated PDSCH transmissions scheduled by DCI 1_0, such as Msg4 PDSCH, the redundancy version rvid applied to the nth transmission opportunity of the TB is determined according to Table 1. In this case, the rvid of the first transmission opportunity is indicated by the RV field in DCI 1_0 and is based on the cycle [0 2 3 1], where n = 0, 1, ..., K-1.

[0403] Taking Figure 16 as an example, the UE is scheduled by DCI 1_0 using RA-RNTI to scramble CRC to perform PDSCH transmission in time slot n, and the number of repeated transmissions K=4, then the UE performs PDSCH repeated transmission from time slot n to time slot n+3, that is, 4 consecutive time slots, and the symbol allocation on each time slot is the same, that is, symbols 2-13 are repeated TB in each time slot, and the rvid of this TB at the 4 transmission opportunities are 0 / 2 / 3 / 1 respectively.

[0404] Example 3: PDSCH processing flow after introducing PDSCH repeated transmission

[0405] During the current random access process, the UE must complete RAR message reception within the RAR window. Considering that repeated Msg2 PDSCH transmissions increase the RAR message reception time, some PDSCH transmissions may occur outside the RAR window, potentially preventing the UE from receiving all repeated PDSCH transmissions. For an example of partial transmissions occurring outside the RAR window, see Figure 17.

[0406] Therefore, it is necessary to enhance the behavior related to receiving RAR messages to ensure that the UE can receive all PDSCH repeated transmissions. At least one of the following solutions can be adopted:

[0407] (1) The requirement of "receiving a RAR message within the RAR window" can be relaxed to "receiving DCI 1_0 with CRC scrambled using RA-RNTI within the RAR window".

[0408] At this time, if the UE successfully receives the RAR message, that is: 1) DCI 1_0 with CRC scrambled using RA-RNTI is detected within the RAR window, 2) and if DCI 1_0 includes the least significant bit (LSB) field of the system radio frame (SFN), which is the same as the LSB of the SFN corresponding to the PRACH sent by the UE, 3) and the UE successfully receives the TB in the corresponding PDSCH, then the UE passes the TB to the upper layer.

[0409] If the UE does not successfully receive the RAR message, that is: 1) DCI 1_0 with CRC scrambled using RA-RNTI is not detected within the RAR window, 2) or if DCI 1_0 includes the LSB field of SFN, but is different from the LSB of the SFN corresponding to the PRACH sent by the UE, 3) or the UE does not successfully receive the TB in the corresponding PDSCH, 4) or the upper layer does not recognize the RAPID associated with the PRACH transmission, then the upper layer can instruct the physical layer to send PRACH.

[0410] Since the UE is only required to receive DCI 1_0 within the RAR window, even if the Msg2 PDSCH retransmission occurs outside the RAR window, the UE is guaranteed to receive all PDSCH retransmissions.

[0411] (2) The RAR window length can be extended. Currently, in the licensed frequency band, the network-configured RAR window length is less than or equal to 10ms. Therefore, the RAR window length can be extended. For example, the network-configured maximum RAR window length can be extended to 40ms to ensure that the UE receives all PDSCH retransmissions within the RAR window.

[0412] After the introduction of Msg2 PDSCH repeated transmission, it can be divided into the following cases:

[0413] (1) If the RAR message is received successfully, the PUSCH transmission time slot for RAR uplink grant scheduling is adjusted to: If the UE receives the last PDSCH retransmission carrying the RAR message in time slot n, the UE receives the last PDSCH retransmission carrying the RAR message in time slot n+k2+Δ+2 μ ·K cell,offet At the same time, the UE may assume that the minimum time interval between the last symbol of the last PDSCH repetition transmission carrying the RAR message with RAR UL grant and the first symbol of the RAR UL grant scheduled PUSCH is equal to N T,1 +N T,2 +0.5ms.

[0414] (2) If the RAR message is not received successfully and the upper layer instructs the physical layer to send PRACH, the UE expects the last symbol of the last PDSCH retransmission to be transmitted no later than N T,1 +0.75ms to send PRACH. As shown in Figure 18, the subsequent timing relationship of Msg2 PDSCH repeated transmission can be assumed to be K cell,offet =0.

[0415] Subsequently, when the UE is not provided with a C-RNTI, in response to the Msg3 PUSCH transmission, the UE will attempt to detect DCI 1_0 with a CRC scrambled with the TC-RNTI and receive its scheduled PDSCH containing the UE contention resolution indicator, i.e., Msg4 PDSCH. In response to the PDSCH containing the UE contention resolution indicator, the UE sends a HARQ-ACK in the PUCCH.

[0416] As shown in Figure 19, the subsequent timing relationship of Msg4 PDSCH repeated transmission is introduced. After the introduction of Msg4 PDSCH repeated transmission, the PUCCH transmission time slot is adjusted to the minimum time between the last symbol of the last PDSCH repeated transmission and the first PUCCH symbol carrying the corresponding HARQ-ACK information is equal to N T,1 +0.75ms.

[0417] The random access process PDSCH retransmission scheme provided in the embodiment of the present application determines the number of PDSCH retransmissions: 1) the number of PDSCH retransmissions broadcast by the system message can flexibly configure the number of PDSCH retransmissions; 2) the protocol introduces candidate values ​​for the number of PDSCH retransmissions, which can realize PDSCH retransmission without increasing the system message signaling overhead; 3) the number of PDSCH retransmissions is implicitly determined, and there is no need to introduce additional signaling and processes for indicating the number of PDSCH retransmissions.

[0418] For the indication of the number of repeated transmissions of PDSCH, 1) the existing field in DCI can be reinterpreted without introducing a new field, which can save DCI signaling overhead; 2) the introduction of the TB scaling field can ensure that the indication function of the existing field is not affected.

[0419] The timing relationship of subsequent transmissions is determined based on the last Msg2 PDSCH and Msg4 PDSCH repeated transmissions to ensure that the UE performs subsequent transmissions after receiving all PDSCH repeated transmissions.

[0420] The solution of the embodiment of the present application is designed based on the NTN system and the random access process, and can be extended to any system that applies the PDSCH repeated transmission solution.

[0421] Figure 20 is a schematic structural diagram of a communication device 2000 according to an embodiment of the present application. The communication device 2000 includes a processor 2010, which can call and run a computer program from a memory to enable the communication device 2000 to implement the method according to the embodiment of the present application.

[0422] In one embodiment, the communication device 2000 may further include a memory 2020. The processor 2010 may call and execute a computer program from the memory 2020 to enable the communication device 2000 to implement the method in the embodiment of the present application.

[0423] The memory 2020 may be a separate device independent of the processor 2010 , or may be integrated into the processor 2010 .

[0424] In one embodiment, the communication device 2000 may further include a transceiver 2030 , and the processor 2010 may control the transceiver 2030 to communicate with other devices. Specifically, the transceiver 2030 may send information or data to other devices, or receive information or data sent by other devices.

[0425] The transceiver 2030 may include a transmitter and a receiver. The transceiver 2030 may further include an antenna, and the number of antennas may be one or more.

[0426] In one embodiment, the communication device 2000 may be a network device of an embodiment of the present application, and the communication device 2000 may implement the corresponding processes implemented by the network device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0427] In one embodiment, the communication device 2000 may be a terminal device of an embodiment of the present application, and the communication device 2000 may implement the corresponding processes implemented by the terminal device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0428] 21 is a schematic structural diagram of a chip 2100 according to an embodiment of the present application. The chip 2100 includes a processor 2110, which can call and execute a computer program from a memory to implement the method according to the embodiment of the present application.

[0429] In one embodiment, the chip 2100 may further include a memory 2120. The processor 2110 may call and execute a computer program from the memory 2120 to implement the method executed by the terminal device or the network device in the embodiment of the present application.

[0430] The memory 2120 may be a separate device independent of the processor 2110 , or may be integrated into the processor 2110 .

[0431] In one embodiment, the chip 2100 may further include an input interface 2130. The processor 2110 may control the input interface 2130 to communicate with other devices or chips, and specifically, may obtain information or data sent by other devices or chips.

[0432] In one embodiment, the chip 2100 may further include an output interface 2140. The processor 2110 may control the output interface 2140 to communicate with other devices or chips, and specifically, may output information or data to other devices or chips.

[0433] In one embodiment, the chip can be applied to the network device in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the network device in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0434] In one embodiment, the chip can be applied to the terminal device in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the terminal device in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0435] The chips used in the network device and the terminal device may be the same chip or different chips.

[0436] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0437] The processor mentioned above may be a general-purpose processor, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or other programmable logic devices, transistor logic devices, discrete hardware components, etc. The general-purpose processor mentioned above may be a microprocessor or any conventional processor, etc.

[0438] The memory mentioned above may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM).

[0439] It should be understood that the above-mentioned memories are exemplary but not restrictive. For example, the memories in the embodiments of the present application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM RAM (DR RAM), etc. In other words, the memories in the embodiments of the present application are intended to include, but are not limited to, these and any other suitable types of memories.

[0440] FIG22 is a schematic block diagram of a communication system 2200 according to an embodiment of the present application. The communication system 2200 includes a terminal device 2210 and a network device 2220 .

[0441] Terminal device 2210, configured to receive repeated transmissions of messages during a random access process;

[0442] The network device 2220 is configured to repeatedly transmit messages in the random access process.

[0443] The terminal device 2210 can be used to implement the corresponding functions implemented by the terminal device in the above method, and the network device 2220 can be used to implement the corresponding functions implemented by the network device in the above method. For the sake of brevity, they are not described here in detail.

[0444] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function in accordance with the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode to another website, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0445] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0446] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0447] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A retransmission method, comprising: A terminal device receives retransmissions of messages in a random access procedure.

2. The method according to claim 1, wherein, The terminal device receiving retransmissions of messages in a random access procedure includes: The terminal device receives the retransmission of the Physical Downlink Shared Channel (PDSCH) based on the number of retransmissions of the PDSCH.

3. The method according to claim 2, wherein, The types of the PDSCH include at least one of the following: The PDSCH scheduled by Downlink Control Information (DCI) scrambled by a Random Access Radio Network Temporary Identifier (RA-RNTI) and Cyclic Redundancy Check (CRC); The PDSCH scheduled by DCI scrambled by a Temporary Cell Radio Network Temporary Identifier (TC-RNTI) and CRC; The PDSCH scheduled by DCI scrambled by a Message B (MsgB-RNTI) and CRC.

4. The method according to claim 2 or 3, wherein The method further includes: The terminal device requests the retransmission of the PDSCH.

5. The method according to claim 4, wherein, The terminal device requesting the retransmission of the PDSCH includes at least one of the following: The terminal device requests the retransmission of the PDSCH according to a specific Physical Random Access Channel (PRACH) format; The terminal device requests the retransmission of the PDSCH according to a random access channel opportunity (RO) for sending the PRACH; The terminal device requests the retransmission of the PDSCH according to a specific PRACH preamble.

6. The method according to any one of claims 2 to 5, wherein, The determination method of the number of retransmissions of the PDSCH includes one of the following: The terminal device determines the number of retransmissions of the PDSCH according to the system message broadcast by the network device; In the case where the system message does not configure the number of retransmissions of the PDSCH, the terminal device determines the number of retransmissions of the PDSCH according to a default value; The terminal device determines the number of retransmissions of the PDSCH according to N, where N is a positive integer.

7. The method according to any one of claims 2 to 5, wherein The determination method of the number of retransmissions of the PDSCH includes one of the following: The terminal device determines the number of retransmissions of the PDSCH according to the number of retransmissions of the PRACH or the number of PRACH sequence retransmissions; The terminal device determines the number of retransmissions of the PDSCH scheduled by DCI scrambled by TC-RNTI and CRC according to the number of retransmissions of the Physical Uplink Shared Channel (PUSCH) sent in the random access procedure; The terminal device determines the number of retransmissions of the PDSCH scheduled by DCI scrambled by TC-RNTI and CRC according to the number of retransmissions of the PDSCH scheduled by DCI scrambled by RA-RNTI and CRC.

8. The method according to any one of claims 2 to 5, wherein The determination method of the number of retransmissions of the PDSCH includes one of the following: The terminal device determines the number of retransmissions of the PDSCH according to a set of candidate values of the number of retransmissions of the PDSCH in the system message broadcast by the network device; In the case where the system message does not configure the set of candidate values of the number of retransmissions of the PDSCH, the terminal device determines the number of retransmissions of the PDSCH according to a default set of candidate values of the number of retransmissions of the PDSCH; The terminal device determines the repetition transmission times of the PDSCH according to a set including candidate values of the repetition transmission times of M PDSCHs, where M is a positive integer.

9. The method according to claim 8, wherein The repetition transmission times of the PDSCH are indicated by an information field in the DCI.

10. The method according to claim 9, wherein The information field is an MCS field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH.

11. The method according to claim 10, wherein, The most significant bit (MSB) of the MCS field indicates the repetition transmission times of the PDSCH, and the least significant bit (LSB) of the MCS field indicates the MCS corresponding to the PDSCH; or, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the repetition transmission times of the PDSCH.

12. The method according to claim 11, wherein, The LSB of the MCS field indicates the MCS index applied in the set of MCS index candidate values, or the MSB of the MCS field indicates the MCS index applied in the set of MCS index candidate values; wherein, the set of MCS index candidate values is configured by the network device through the system message; or, in the case where the set of MCS index candidate values is not configured, the default set is used as the set of MCS index candidate values.

13. The method according to claim 9, wherein, The information field includes a repetition transmission times field, and the repetition transmission times field is used to indicate the repetition transmission times of the PDSCH.

14. The method according to claim 13, wherein, The repetition transmission times field occupies the reserved bits in the DCI.

15. The method according to claim 14, wherein The repetition transmission times field occupies the reserved bits in the downlink allocation index (DAI) field of the DCI scrambled by the TC-RNTI for the CRC.

16. The method according to any one of claims 2 to 15, wherein, The repetition transmission times of the PDSCH is K, and the terminal device receives the repetition transmission of the PDSCH based on the repetition transmission times of the PDSCH, including: The terminal device receives the repetition transmission of the PDSCH in K consecutive time slots; wherein, at least one of the following characteristics exists between the K consecutive time slots and the PDSCH: The PDSCH uses the same symbol allocation in the K consecutive time slots; The terminal device repeatedly receives the transport block (TB) in the PDSCH within each symbol allocation in each of the K consecutive time slots; The PDSCH is a single transmission layer.

17. The method according to any one of claims 2 to 16, wherein The redundancy version identifier corresponding to the first transmission opportunity of the repetition transmission of the PDSCH is determined based on at least one of the following: The default value of the redundancy version identifier; The indication in the redundancy version field in the DCI.

18. The method according to any one of claims 1 to 17, wherein The method further includes: The terminal device performs repetition transmission on the physical random access channel (PRACH).

19. The method according to claim 18, wherein, The method further includes: The terminal device determines the random access response (RAR) window based on the radio opportunity (RO) corresponding to the repetition transmission of the last PRACH.

20. The method according to claim 19, wherein, Determining the position of the RAR window includes at least one of the following: The terminal device determines the start position of the RAR window according to the symbol after the last symbol of the RO corresponding to the repetition transmission of the last PRACH; The terminal device determines the start position of the RAR window based on the symbol after the last symbol of the RO corresponding to the repeated transmission of the last PRACH, and the first symbol of the earliest control resource set (CORESET) where the PDCCH in the common search space (CSS) set of the type-1 physical downlink control channel (Type1-PDCCH) is received.

21. The method according to any one of claims 1 to 20, wherein Successfully receiving a RAR message within the RAR window includes at least one of the following: Detecting a DCI scrambled with RA-RNTI CRC within the RAR window; When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, if the DCI includes the LSB field of the system frame number (SFN), and the LSB field in the DCI is the same as the LSB of the SFN corresponding to the PRACH transmitted by the terminal device; When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, the terminal device successfully receives the transport block (TB) within the PDSCH scheduled by the DCI; The higher layer of the terminal device parses the TB to obtain the RAPID associated with the PRACH transmission.

22. The method according to any one of claims 1 to 21, wherein, Not successfully receiving a RAR message within the RAR window includes one of the following: Not detecting a DCI scrambled with RA-RNTI CRC within the RAR window; When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, if the DCI includes the LSB field of the SFN, but the LSB field in the DCI is different from the LSB of the SFN corresponding to the PRACH transmitted by the terminal device; When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, the terminal device does not receive the TB within the PDSCH scheduled by the DCI; The higher layer of the terminal device does not identify the random access preamble identifier (RAPID) associated with the PRACH transmission.

23. The method according to any one of claims 1 to 22, wherein, The maximum configurable length of the RAR window is adjusted from a first length to a second length, and the second length is greater than the first length; The terminal device receiving repeated transmissions of messages during the random access procedure includes: The terminal device receives the RAR message within the RAR window whose maximum length can be configured as the second length.

24. The method according to any one of claims 1 to 23, wherein, The method further includes: The terminal device determines the transmission time slot of the PUSCH scheduled by the RAR uplink (UL) grant based on the repeated transmission of the last PDSCH carrying the RAR message received.

25. The method according to claim 24, wherein, The PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot of the repeated transmission of the last PDSCH carrying the RAR message, and the first duration is determined based on the slot-level offset from the RAR UL grant to the PUSCH.

26. The method according to claim 24 or 25, wherein The minimum time interval between the last symbol of the repeated transmission of the last PDSCH carrying the RAR message with a RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time.

27. The method according to any one of claims 1 to 26, wherein, The method further includes: When the terminal device fails to successfully receive the RAR message and the upper layer instructs the physical layer to send a PRACH, the terminal device expects to send the PRACH no later than a second duration after the last symbol of the last repetition transmission of the last PDSCH; wherein, the second duration is determined based on the PDSCH processing time.

28. The method according to any one of claims 1 to 27, wherein The PDSCH scheduled by DCI scrambled with TC-RNTI for CRC is the PDSCH containing the terminal device contention resolution identifier, and the method further includes: In response to the PDSCH containing the terminal device contention resolution identifier, the terminal device sends HARQ-ACK in the PUCCH. Wherein, the PUCCH transmission time slot is adjusted so that the minimum time interval between the last symbol of the last repetition transmission of the last PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; wherein, the third duration is determined based on the PDSCH processing time.

29. A repetition transmission method, including: The network device repeats the transmission of messages in the random access process.

30. The method according to claim 29, wherein The network device repeats the transmission of messages in the random access process, including: The network device repeats the transmission of the PDSCH based on the repetition count of the physical downlink shared channel PDSCH.

31. The method according to claim 30, wherein, The types of the PDSCH include at least one of the following: The PDSCH scheduled by downlink control information DCI scrambled with a random access radio network temporary identifier RA-RNTI for cyclic redundancy check CRC; The PDSCH scheduled by DCI scrambled with a temporary cell radio network temporary identifier TC-RNTI for CRC; The PDSCH scheduled by DCI scrambled with a message B MsgB-RNTI for CRC.

32. The method according to claim 30 or 31, wherein The method further includes: The network device receives a request from the terminal device for the repetition transmission of the PDSCH.

33. The method according to claim 32, wherein The network device receiving a request from the terminal device for the repetition transmission of the PDSCH includes at least one of the following: The network device receives the request from the terminal device for the repetition transmission of the PDSCH according to a specific PRACH format; The network device receives the request from the terminal device for the repetition transmission of the PDSCH according to the RO for sending the PRACH; The network device receives the request from the terminal device for the repetition transmission of the PDSCH according to a specific PRACH preamble.

34. The method according to any one of claims 30 to 33, wherein, The determination method of the repetition count of the PDSCH includes one of the following: The network device broadcasts a repetition count of the PDSCH through a system message; In the case where the system message does not configure the repetition count of the PDSCH, the network device determines the repetition count of the PDSCH according to a default value; Determine the repetition count of the PDSCH according to N, where N is a positive integer.

35. The method according to any one of claims 30 to 33, wherein, The determination method of the repetition count of the PDSCH includes one of the following: The network device determines the repetition count of the PDSCH according to the repetition count of the PRACH sent by the terminal device or the repetition count of the PRACH sequence. The network device determines the number of repetitions of the PDSCH scheduled by the DCI scrambled with the TC-RNTI based on the number of repetitions of the Physical Uplink Shared Channel (PUSCH) sent by the terminal device during the random access procedure; The network device determines the number of repetitions of the PDSCH scheduled by the DCI scrambled with the TC-RNTI based on the number of repetitions of the PDSCH scheduled by the DCI scrambled with the RA-RNTI; 36. The method according to any one of claims 30 to 33, wherein, The determination method of the number of repetitions of the PDSCH includes one of the following: The network device broadcasts a set of candidate values of the number of repetitions of the PDSCH through the system message; In the case where the system message does not configure the set of candidate values of the number of repetitions of the PDSCH, the network device determines the number of repetitions of the PDSCH according to the default set of candidate values of the number of repetitions of the PDSCH; The network device determines the number of repetitions of the PDSCH according to a set including M candidate values of the number of repetitions of the PDSCH, where M is a positive integer; 37. The method according to claim 36, wherein, The number of repetitions of the PDSCH is indicated by an information field in the DCI; 38. The method according to claim 37, wherein, The information field is the MCS field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH; 39. The method according to claim 38, wherein, The MSB of the MCS field indicates the number of repetitions of the PDSCH, and the LSB of the MCS field indicates the MCS corresponding to the PDSCH; or, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the number of repetitions of the PDSCH; 40. The method according to claim 39, wherein, The LSB of the MCS field indicates the MCS index applied in the set of MCS index candidate values, or the MSB of the MCS field indicates the MCS index applied in the set of MCS index candidate values; Wherein, the set of MCS index candidate values is configured by the network device through the system message; or, in the case where the set of MCS index candidate values is not configured, the default set is used as the set of MCS index candidate values; 41. The method according to claim 37, wherein, The information field includes a repetition number field, and the repetition number field is used to indicate the number of repetitions of the PDSCH; 42. The method according to claim 41, wherein, The repetition number field occupies the reserved bits in the DCI; 43. The method according to claim 42, wherein The repetition number field occupies the reserved bits of the Downlink Allocation Index (DAI) field of the DCI scrambled with the TC-RNTI; 44. The method according to any one of claims 30 to 43, wherein, When the number of repetitions of the PDSCH is K, the network device performs repeated transmission of the PDSCH based on the number of repetitions of the PDSCH, including: The network device performs repeated transmission of the PDSCH in K consecutive time slots; Wherein, at least one of the following characteristics is shared by the K consecutive time slots and the PDSCH: The PDSCH uses the same symbol allocation in the K consecutive time slots; The Transport Block (TB) in the PDSCH is repeatedly transmitted within each symbol allocation in each of the K consecutive time slots; The PDSCH is a single transmission layer.

45. The method according to any one of claims 30 to 44, wherein, The redundancy version identifier corresponding to the first transmission opportunity of the repeated transmission of the PDSCH is determined based on at least one of the following: The default value of the redundancy version identifier; The redundancy version field indication in the DCI.

46. The method according to any one of claims 29 to 45, wherein, The method further includes: The network device receives the repeated transmission of the PRACH.

47. The method according to claim 46, wherein, The network device repeats the transmission of the messages in the random access procedure, including: The network device sends the RAR message based on the repeated transmission of the last PRACH.

48. The method according to claim 47, wherein, The maximum configurable length of the RAR window is adjusted from a first length to a second length, and the second length is greater than the first length.

49. The method according to any one of claims 29 to 48, wherein The method further includes: The network device receives the PUSCH scheduled by the RAR UL grant, and the transmission time slot of the PUSCH scheduled by the RAR UL grant is determined by the terminal device based on the repeated transmission of the last PDSCH carrying the RAR message.

50. The method according to claim 49, wherein The PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot of the repeated transmission of the last PDSCH carrying the RAR message, and the first duration is determined based on the slot-level offset from the RAR UL grant to the PUSCH.

51. The method according to claim 49 or 50, wherein, The minimum time interval between the last symbol of the repeated transmission of the last PDSCH carrying the RAR message with the RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time.

52. The method according to any one of claims 29 to 51, wherein, The method further includes: The network device receives the PRACH sent by the terminal device when the RAR message is not successfully received; wherein, the terminal device expects to send the PRACH no later than a second duration after the last symbol of the repeated transmission of the last PDSCH; wherein, the second duration is determined based on the PDSCH processing time.

53. The method according to any one of claims 29 to 52, wherein, The PDSCH scheduled by the DCI using the TC-RNTI to scramble the CRC is the PDSCH containing the terminal device contention resolution identifier, and the method further includes: The network device receives the HARQ-ACK carried in the PUCCH; Wherein, the PUCCH transmission time slot is adjusted so that the minimum time interval between the last symbol of the repeated transmission of the last PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; wherein, the third duration is determined based on the PDSCH processing time.

54. A terminal device, comprising: A receiving unit, configured to receive the repeated transmission of the messages in the random access procedure.

55. The terminal device according to claim 54, wherein, The receiving unit is further configured to receive the repeated transmission of the PDSCH based on the number of repeated transmissions of the physical downlink shared channel PDSCH.

56. The terminal device according to claim 55, wherein, The type of the PDSCH includes at least one of the following: The PDSCH scheduled by the downlink control information DCI using the random access radio network temporary identifier RA-RNTI to scramble the cyclic redundancy check CRC; The PDSCH scheduled by the DCI using the temporary cell radio network temporary identifier TC-RNTI to scramble the CRC; PDSCH scheduled by DCI with CRC scrambled by MsgB - RNTI.

57. The terminal device according to claim 55 or 56, wherein, The terminal device further includes: A request unit for requesting retransmission of the PDSCH.

58. The terminal device according to claim 57, wherein, The request unit is used to perform at least one of the following: Request retransmission of the PDSCH according to a specific physical random access channel (PRACH) format; Request retransmission of the PDSCH according to the random access channel occasion (RO) for sending the PRACH; Request retransmission of the PDSCH according to a specific PRACH preamble.

59. The terminal device according to any one of claims 55 to 58, wherein, The terminal device further includes a first processing unit, and the first processing unit determines the number of retransmissions of the PDSCH in one of the following ways: Determine the number of retransmissions of the PDSCH according to the system message broadcast by the network device; In the case where the system message does not configure the number of retransmissions of the PDSCH, determine the number of retransmissions of the PDSCH according to the default value; Determine the number of retransmissions of the PDSCH according to N, where N is a positive integer.

60. The terminal device according to any one of claims 55 to 58, wherein, The terminal device further includes a second processing unit, and the second processing unit determines the number of retransmissions of the PDSCH in one of the following ways: Determine the number of retransmissions of the PDSCH according to the number of retransmissions of the PRACH or the number of PRACH sequence repetitions; Determine the number of retransmissions of the PDSCH scheduled by DCI with CRC scrambled by TC - RNTI according to the number of retransmissions of the physical uplink shared channel (PUSCH) sent during the random access process; Determine the number of retransmissions of the PDSCH scheduled by DCI with CRC scrambled by TC - RNTI according to the number of retransmissions of the PDSCH scheduled by DCI with CRC scrambled by RA - RNTI.

61. The terminal device according to any one of claims 55 to 58, wherein, The terminal device further includes a third processing unit, and the third processing unit determines the number of retransmissions of the PDSCH in one of the following ways: Determine the number of retransmissions of the PDSCH according to the set of candidate values of the number of retransmissions of the PDSCH in the system message broadcast by the network device; In the case where the system message does not configure the set of candidate values of the number of retransmissions of the PDSCH, determine the number of retransmissions of the PDSCH according to the default set of candidate values of the number of retransmissions of the PDSCH; Determine the number of retransmissions of the PDSCH according to the set including M candidate values of the number of retransmissions of the PDSCH, where M is a positive integer.

62. The terminal device according to claim 61, wherein, The number of retransmissions of the PDSCH is indicated by the information field in the DCI.

63. The terminal device according to claim 62, wherein, The information field is the MCS field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH.

64. The terminal device according to claim 63, wherein, The MSB of the MCS field indicates the number of retransmissions of the PDSCH, and the LSB of the MCS field indicates the MCS corresponding to the PDSCH; or, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the number of retransmissions of the PDSCH.

65. The terminal device according to claim 64, wherein, The LSB of the MCS field indicates the MCS index applied in the set of MCS index candidates, or the MSB of the MCS field indicates the MCS index applied in the set of MCS index candidates; Wherein, the set of MCS index candidates is configured by the network device through a system message; or, in the case where the set of MCS index candidates is not configured, the default set is used as the set of MCS index candidates.

66. The terminal device according to claim 62, wherein, The information field includes a repetition count field, and the repetition count field is used to indicate the repetition count of the PDSCH.

67. The terminal device according to claim 66, wherein, The repetition count field occupies reserved bits in the DCI.

68. The terminal device according to claim 67, wherein, The repetition count field occupies reserved bits in the downlink allocation index DAI field of the DCI scrambled by TC-RNTI.

69. The terminal device according to any one of claims 55 to 68, wherein, The repetition count of the PDSCH is K, and the terminal device receives the repeated transmission of the PDSCH based on the repetition count of the PDSCH, including: The terminal device receives the repeated transmission of the PDSCH in K consecutive time slots; Wherein, at least one of the following characteristics is shared by the K consecutive time slots and the PDSCH: The PDSCH uses the same symbol allocation in the K consecutive time slots; The terminal device repeatedly receives the TB in the PDSCH within each symbol allocation in each of the K consecutive time slots; The PDSCH is a single transmission layer.

70. The terminal device according to any one of claims 55 to 69, wherein, The redundancy version identifier corresponding to the first transmission opportunity of the repeated transmission of the PDSCH is determined based on at least one of the following: The default value of the redundancy version identifier; The redundancy version field indication in the DCI.

71. The terminal device according to any one of claims 54 to 70, wherein, The terminal device further includes: A first transmission unit for repeating the transmission of the PRACH.

72. The terminal device according to claim 71, wherein, The terminal device further includes: A fourth processing unit for determining a random access response RAR window based on the RO corresponding to the repeated transmission of the last PRACH.

73. The terminal device according to claim 72, wherein, The fourth processing unit determines the position of the RAR window including at least one of the following: Determining the start position of the RAR window according to the symbol after the last symbol of the RO corresponding to the repeated transmission of the last PRACH; Determining the start position of the RAR window according to the symbol after the last symbol of the RO corresponding to the repeated transmission of the last PRACH and the first symbol of the earliest control resource set CORESET where the PDCCH in the common search space CSS set of the type 1 physical downlink control channel Type1-PDCCH is received.

74. The terminal device according to any one of claims 54 to 73, wherein, Successfully receiving an RAR message within the RAR window includes at least one of the following: Detecting a DCI scrambled by RA-RNTI CRC within the RAR window; In the case of detecting a DCI scrambled by RA-RNTI CRC within the RAR window, if the DCI includes the LSB field of the system radio frame SFN and the LSB field in the DCI is the same as the LSB of the SFN corresponding to the PRACH transmitted by the terminal device; When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, the terminal device successfully receives the transport block TB within the PDSCH scheduled by the DCI; The higher layer of the terminal device parses the TB to obtain the RAPID associated with the PRACH transmission.

75. The terminal device according to any one of claims 54 to 74, wherein, Failure to successfully receive the RAR message within the RAR window includes one of the following: No DCI scrambled with RA-RNTI CRC is detected within the RAR window; When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, if the LSB field of the SFN is included in the DCI, but the LSB field in the DCI is different from the LSB of the SFN corresponding to the PRACH sent by the terminal device; When a DCI scrambled with RA-RNTI CRC is detected within the RAR window, the terminal device does not receive the TB within the PDSCH scheduled by the DCI; The higher layer of the terminal device does not recognize the random access preamble identifier RAPID associated with the PRACH transmission.

76. The terminal device according to any one of claims 54 to 75, wherein, The maximum configurable length of the RAR window is adjusted from a first length to a second length, and the second length is greater than the first length; The receiving unit is further configured to receive the RAR message within the RAR window whose maximum length can be configured as the second length.

77. The terminal device according to any one of claims 54 to 76, wherein, The terminal device further includes: A fifth processing unit, configured to determine the PUSCH transmission time slot scheduled by the RAR uplink UL grant based on the retransmission of the last PDSCH carrying the RAR message received.

78. The terminal device according to claim 77, wherein, The PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot of the retransmission of the last PDSCH carrying the RAR message, and the first duration is determined based on the time slot-level offset from the RAR UL grant to the PUSCH.

79. The terminal device according to claim 77 or 78, wherein, The minimum time interval between the last symbol of the retransmission of the last PDSCH carrying the RAR message with the RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time.

80. The terminal device according to any one of claims 54 to 79, wherein, The terminal device further includes: A second sending unit, configured to, when the higher layer instructs the physical layer to send a PRACH in case of failure to successfully receive the RAR message, the terminal device expects to send the PRACH no later than a second duration after the last symbol of the retransmission of the last PDSCH; wherein, the second duration is determined based on the PDSCH processing time.

81. The terminal device according to any one of claims 54 to 80, wherein, The PDSCH scheduled by the DCI scrambled with TC-RNTI CRC is the PDSCH containing the terminal device contention resolution identifier, and the terminal device further includes: A third sending unit, configured to send HARQ-ACK in the PUCCH in response to the PDSCH containing the terminal device contention resolution identifier. Wherein, the PUCCH transmission time slot is adjusted such that the minimum time interval between the last symbol of the repeated transmission of the last PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; wherein, the third duration is determined based on the PDSCH processing time.

82. A network device, comprising: A sending unit, configured to perform repeated transmission on the messages in a random access process.

83. The network device according to claim 82, wherein, The sending unit is further configured to perform repeated transmission on the PDSCH based on the number of repeated transmissions of the physical downlink shared channel PDSCH.

84. The network device according to claim 83, wherein, The types of the PDSCH include at least one of the following: A PDSCH scheduled by downlink control information DCI scrambled by a random access radio network temporary identity RA-RNTI cyclic redundancy check CRC; A PDSCH scheduled by DCI scrambled by a temporary cell radio network temporary identity TC-RNTI CRC; A PDSCH scheduled by DCI scrambled by a message B MsgB-RNTI CRC.

85. The network device according to claim 83 or 84, wherein, The network device further comprises: A first receiving unit, configured to receive a request from a terminal device for repeated transmission of the PDSCH.

86. The network device according to claim 85, wherein, The first receiving unit is further configured to perform at least one of the following: Receive the request from the terminal device for repeated transmission of the PDSCH according to a specific PRACH format; Receive the request from the terminal device for repeated transmission of the PDSCH according to an RO for sending the PRACH; Receive the request from the terminal device for repeated transmission of the PDSCH according to a specific PRACH preamble.

87. The network device according to any one of claims 83 to 86, wherein The network device further comprises a first processing unit, and the first processing unit determines the number of repeated transmissions of the PDSCH in one of the following ways: Broadcast the number of repeated transmissions of a PDSCH through a system message; In the case where the system message does not configure the number of repeated transmissions of the PDSCH, determine the number of repeated transmissions of the PDSCH according to a default value; Determine the number of repeated transmissions of the PDSCH according to N, where N is a positive integer.

88. The network device according to any one of claims 83 to 86, wherein, The network device further comprises a second processing unit, and the second processing unit determines the number of repeated transmissions of the PDSCH in one of the following ways: Determine the number of repeated transmissions of the PDSCH according to the number of repeated transmissions of the PRACH or the number of PRACH sequence repetitions sent by the terminal device; Determine the number of repeated transmissions of the PDSCH scheduled by DCI scrambled by TC-RNTI according to the number of repeated transmissions of the physical uplink shared channel PUSCH sent by the terminal device in a random access process; Determine the number of repeated transmissions of the PDSCH scheduled by DCI scrambled by TC-RNTI according to the number of repeated transmissions of the PDSCH scheduled by DCI scrambled by RA-RNTI.

89. The network device according to any one of claims 83 to 86, wherein, The network device further comprises a third processing unit, and the third processing unit determines the number of repeated transmissions of the PDSCH in one of the following ways: Broadcast a set of candidate values of the number of repeated transmissions of the PDSCH through a system message; In the case where the system message does not configure the set of candidate values for the repetition transmission times of the PDSCH, determine the repetition transmission times of the PDSCH according to the default set of candidate values for the repetition transmission times of the PDSCH; Determine the repetition transmission times of the PDSCH according to a set including M candidate values for the repetition transmission times of the PDSCH, where M is a positive integer.

90. The network device according to claim 89, wherein, The repetition transmission times of the PDSCH are indicated by an information field in the DCI.

91. The network device according to claim 90, wherein, The information field is the MCS field, and the MCS field is used to indicate the MCS corresponding to the scheduled PDSCH.

92. The network device according to claim 91, wherein, The MSB of the MCS field indicates the repetition transmission times of the PDSCH, and the LSB of the MCS field indicates the MCS corresponding to the PDSCH; or, the MSB of the MCS field indicates the MCS corresponding to the PDSCH, and the LSB of the MCS field indicates the repetition transmission times of the PDSCH.

93. The network device according to claim 92, wherein, The LSB of the MCS field indicates the MCS index applied in the set of MCS index candidate values, or the MSB of the MCS field indicates the MCS index applied in the set of MCS index candidate values; Wherein, the set of MCS index candidate values is configured by the network device through the system message; or, in the case where the set of MCS index candidate values is not configured, use the default set as the set of MCS index candidate values.

94. The network device according to claim 90, wherein, The information field includes a repetition transmission times field, and the repetition transmission times field is used to indicate the repetition transmission times of the PDSCH.

95. The network device according to claim 94, wherein, The repetition transmission times field occupies the reserved bits in the DCI.

96. The network device according to claim 95, wherein, The repetition transmission times field occupies the reserved bits of the downlink allocation index DAI field of the DCI scrambled with the TC-RNTI.

97. The network device according to any one of claims 83 to 96, wherein, The repetition transmission times of the PDSCH is K, and the sending unit is further configured to repetitively transmit the PDSCH in K consecutive time slots; Wherein, at least one of the following characteristics is shared by the K consecutive time slots and the PDSCH: The PDSCH uses the same symbol allocation in the K consecutive time slots; Repetitively transmit the TB in the PDSCH within each symbol allocation in each of the K consecutive time slots; The PDSCH is a single transmission layer.

98. The network device according to any one of claims 83 to 97, wherein, The redundancy version identifier corresponding to the first transmission opportunity of the repetitive transmission of the PDSCH is determined based on at least one of the following: The default value of the redundancy version identifier; The indication of the redundancy version field in the DCI.

99. The network device according to any one of claims 82 to 98, wherein, The network device further includes: A second receiving unit, configured to receive the repetitive transmission of the PRACH.

100. The network device according to claim 99, wherein, The sending unit is configured to send the RAR message based on the repetitive transmission of the last PRACH.

101. The network device according to claim 100, wherein, The maximum length of the configurable RAR window is adjusted from a first length to a second length, and the second length is greater than the first length.

102. The network device according to any one of claims 82 to 101, wherein, The network device further includes: A third receiving unit, configured to receive the PUSCH scheduled by the RAR UL grant, and the transmission time slot of the PUSCH scheduled by the RAR UL grant is determined by the terminal device based on the repetitive transmission of the last PDSCH carrying the RAR message.

103. The network device according to claim 102, wherein, The PUSCH transmission time slot is adjusted to be delayed by a first duration after the time slot of the repeated transmission of the last PDSCH carrying the RAR message, and the first duration is determined based on the slot-level offset from the RAR UL grant to the PUSCH.

104. The network device according to claim 102 or 103, wherein, The minimum time interval between the last symbol of the repeated transmission of the last PDSCH carrying the RAR message with the RAR uplink UL grant and the first symbol of the PUSCH scheduled by the RAR UL grant is determined based on the PDSCH processing time and the PUSCH preparation time.

105. The network device according to any one of claims 82 to 104, wherein, The sending unit is configured to receive a PRACH sent by a terminal device when the terminal device fails to successfully receive the RAR message; wherein, the terminal device expects to send the PRACH no later than a second duration after the last symbol of the repeated transmission of the last PDSCH; and the second duration is determined based on the PDSCH processing time.

106. The network device according to any one of claims 82 to 105, wherein, The PDSCH scheduled by the DCI scrambled with the TC-RNTI for the CRC is a PDSCH containing the terminal device contention resolution identifier, and the network device further includes: A fourth receiving unit, configured to receive the HARQ-ACK carried in the PUCCH. Wherein, the PUCCH transmission time slot is adjusted such that the minimum time interval between the last symbol of the repeated transmission of the last PDSCH and the first symbol of the PUCCH carrying the corresponding HARQ-ACK information is equal to a third duration; and the third duration is determined based on the PDSCH processing time.

107. A terminal device, comprising: A processor and a memory, where the memory is configured to store a computer program, and the processor is configured to call and run the computer program stored in the memory, so that the terminal device executes the method according to any one of claims 1 to 28.

108. A network device, comprising: A processor and a memory, where the memory is configured to store a computer program, and the processor is configured to call and run the computer program stored in the memory, so that the network device executes the method according to any one of claims 29 to 53.

109. A chip, comprising: A processor, configured to call and run a computer program from a memory, so that a device installed with the chip executes the method according to any one of claims 1 to 28 or 29 to 53.

110. A computer-readable storage medium, configured to store a computer program, and when the computer program is run by a device, the device executes the method according to any one of claims 1 to 28 or 29 to 53.

111. A computer program product, including computer program instructions, and the computer program instructions cause a computer to execute the method according to any one of claims 1 to 28 or 29 to 53.

112. A computer program, and the computer program causes a computer to execute the method according to any one of claims 1 to 28 or 29 to 53.

113. A communication system, including: A terminal device, configured to execute the method according to any one of claims 1 to 28; A network device, configured to execute the method according to any one of claims 29 to 53.

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