Downlink coverage enhancement optimization method based on 5g non-ground network and terminal equipment

Abstract

The application discloses a 5G non-ground network-based downlink coverage enhancement optimization method and a terminal device. The method comprises the following steps: acquiring a channel quality measurement value of a downlink reference signal; in the case that the channel quality measurement value is not greater than a first preset threshold, sending request information to a network side through a message 3, wherein the request information is used for requesting a new repetition transmission number; the new repetition transmission number is greater than a preset repetition transmission number; the new repetition transmission number and the preset repetition transmission number are both the number of repeated transmissions of the same message 4 in a physical downlink shared channel; and the preset repetition transmission number is a default repetition transmission number which is preset by the terminal device and the network side in a non-broadcast manner. The application solves the technical problem that a related repetition transmission configuration method is difficult to simultaneously consider the flexibility of air interface signaling overhead and downlink coverage enhancement.

Description

Technical Field

[0001] This application relates to the field of 5G downlink coverage enhancement, and more specifically, to a downlink coverage enhancement optimization method and terminal device based on 5G non-terrestrial networks. Background Technology

[0002] The 3GPP TSG RAN WG1 #120 meeting presented three methods for enhancing downlink coverage at the Msg4 PDSCH link level. Option 1 uses Downlink Control Information (DCI) to indicate the number of retransmissions for a specific UE. The first advantage of Option 1 is its high flexibility, manifested in two ways: firstly, UEs can be configured independently; different UEs at the beam center and beam edges can achieve different configurations through DCI; secondly, DCI has low latency, making it suitable for scenarios with rapid UE movement. The second advantage of Option 1 is that DCI can be implemented only at the physical layer, without involving modifications to higher-layer protocols or inter-layer interactions.

[0003] However, choosing option 1, which configures each UE via DCI, also results in a higher volume of air interface signaling.

[0004] Option 2 configures the number of repeated transmissions of Msg4 through System Information Block 1 (SIB1). The advantage of option 2 is that the SIB1 method can be uniformly configured for all UEs within the cell, which greatly saves air interface signaling overhead.

[0005] However, the SIB1 method of option 2 requires modifications to the Radio Resource Control (RRC) layer, which requires interaction between the RRC and the lower physical layer, making it slightly more complex to implement than the DCI method.

[0006] Option 3 implicitly indicates the Msg4 PDSCH retransmission count by using the number of retransmissions of the SIB1 Physical Downlink Shared Channel (PDSCH). The advantage of option 3 is that no additional air interface signaling is required to complete the configuration, further saving air interface signaling overhead.

[0007] Option 3 couples the two repetition counts together. However, under the same coverage requirements, Msg4 needs more repetitions than SIB1, necessitating the determination of a mapping method for the two repetition counts, which further sacrifices flexibility.

[0008] In summary, none of the above three options can simultaneously balance the flexibility of increased air interface signaling overhead and enhanced downlink coverage.

[0009] There is currently no effective solution to the above problems. Summary of the Invention

[0010] This application provides a downlink coverage enhancement optimization method and terminal device based on 5G non-terrestrial networks, so as to at least solve the technical problem that related repetitive transmission configuration methods are difficult to simultaneously take into account air interface signaling overhead and the flexibility of downlink coverage enhancement.

[0011] According to one aspect of this application, a downlink coverage enhancement optimization method based on a 5G non-terrestrial network is provided, applied to a terminal device in a 5G non-terrestrial network, comprising: acquiring a channel quality measurement value of a downlink reference signal; when the channel quality measurement value is not greater than a first preset threshold, sending a request message to the network side via message 3, wherein the request message is used to request a new number of retransmissions; the new number of retransmissions is greater than a preset number of retransmissions; both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel; the preset number of retransmissions is a default number of retransmissions preset by the terminal device and the network side respectively in a non-broadcast manner, wherein the preset number of retransmissions on the terminal device and the preset number of retransmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block.

[0012] Optionally, after sending the request information to the network side via message 3, the method further includes: receiving the response information sent by the network side in response to the request information, wherein the response information includes at least: a first number of repeated transmissions; the first number of repeated transmissions is determined by the network side based on the network side's resource load index, the resource load index being used to quantitatively characterize the occupancy of downlink transmission resources; the first number of repeated transmissions determined when the value of the resource load index is greater than a second preset threshold is less than or equal to the first number of repeated transmissions determined when the value of the resource load index is not greater than the second preset threshold.

[0013] Optionally, the response information is carried in the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

[0014] Optionally, before obtaining the channel quality measurement value of the downlink reference signal, the method further includes: determining the coverage location type of the terminal device relative to the downlink transmission beam, wherein the coverage location type includes beam center region and beam edge region; obtaining the channel quality measurement value of the downlink reference signal includes: obtaining the channel quality measurement value of the downlink reference signal when the coverage location type is beam edge region.

[0015] Optionally, the method further includes: when the coverage location type is a beam center area, receiving message 4 in the physical downlink shared channel based on a preset number of retransmissions.

[0016] Optionally, the method further includes: receiving message 4 in the physical downlink shared channel based on a preset number of repeated transmissions when the channel quality measurement value is greater than a first preset threshold.

[0017] Optionally, the request information is carried in at least one of the following: the media access control unit of message 3, the information element in the radio resource control message carried by the physical uplink shared channel of message 3, and the preset bit field in message 3, wherein the preset bit field includes: one bit.

[0018] According to another aspect of this application, a downlink coverage enhancement optimization method based on a 5G non-terrestrial network is also provided, applied to a terminal device in a 5G non-terrestrial network, comprising: acquiring channel quality measurement values ​​of downlink reference signals; determining a target preset channel quality measurement threshold interval in which the channel quality measurement values ​​are located among multiple preset channel quality measurement threshold intervals; determining a target preset retransmission number corresponding to the target preset channel quality measurement threshold interval among multiple preset retransmission numbers, wherein the preset retransmission number is the number of times the same message 4 is retransmitted in the physical downlink shared channel; and sending a request information to the network side through message 3, wherein the request information includes at least the target preset retransmission number.

[0019] Optionally, after sending the request information to the network side via message 3, the method further includes: receiving the response information sent by the network side in response to the request information, wherein the response information includes at least: a second number of repeated transmissions; the second number of repeated transmissions is determined by the network side based on the network side's resource load index, the resource load index being used to quantitatively characterize the occupancy of downlink transmission resources; the second number of repeated transmissions determined when the value of the resource load index is greater than a third preset threshold is less than or equal to the second number of repeated transmissions determined when the value of the resource load index is not greater than the third preset threshold.

[0020] Optionally, the response information is carried in the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

[0021] According to another aspect of this application, a terminal device is also provided, comprising: a first acquisition module, configured to acquire channel quality measurement values ​​of downlink reference signals; and a first transmission module, configured to send request information to the network side via message 3 when the channel quality measurement value is not greater than a first preset threshold, wherein the request information is used to request a new number of retransmissions; the new number of retransmissions is greater than a preset number of retransmissions; both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel; the preset number of retransmissions is a default number of retransmissions preset by the terminal device and the network side respectively in a non-broadcast manner, wherein the preset number of retransmissions on the terminal device and the preset number of retransmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block.

[0022] According to another aspect of this application, a terminal device is also provided, comprising: a second acquisition module for acquiring channel quality measurement values ​​of downlink reference signals; a first determination module for determining a target preset channel quality measurement threshold interval in which the channel quality measurement value is located among multiple preset channel quality measurement threshold intervals; a second determination module for determining a target preset retransmission number corresponding to the target preset channel quality measurement threshold interval among multiple preset retransmission numbers, wherein the preset retransmission number is the number of times the same message 4 is retransmitted in the physical downlink shared channel; and a second sending module for sending request information to the network side through message 3, wherein the request information includes at least the target preset retransmission number.

[0023] In this application, the channel quality measurement value of the downlink reference signal is obtained. When the channel quality measurement value is not greater than a first preset threshold, a request information is sent to the network side through message 3. The request information is used to request a new number of retransmissions. The new number of retransmissions is greater than the preset number of retransmissions. Both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel. The preset number of retransmissions is the default number of retransmissions preset by the terminal device and the network side in a non-broadcast manner. The preset number of retransmissions on the terminal device and the preset number of retransmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block. This achieves the goal of simultaneously taking into account the air interface signaling overhead and the flexibility of downlink coverage enhancement, thereby achieving the technical effect of improving the success rate of random access. This solves the technical problem that related retransmission configuration methods are difficult to simultaneously take into account the air interface signaling overhead and the flexibility of downlink coverage enhancement. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0025] Figure 1 This is a flowchart of a downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application;

[0026] Figure 2 This is a flowchart of another downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application;

[0027] Figure 3 This is a flowchart of another downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application;

[0028] Figure 4 This is a flowchart of another downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application;

[0029] Figure 5 This is a flowchart of another downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application;

[0030] Figure 6 This is a structural diagram of a terminal device according to an embodiment of this application;

[0031] Figure 7 This is a structural diagram of another terminal device according to an embodiment of this application. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] To better understand the embodiments of this application, the technical terms involved in the embodiments of this application are explained below:

[0035] Message 3 (Msg3): refers to the third uplink message in the UE random access procedure, which is sent by the UE through the physical uplink shared channel and can carry an RRC setup request.

[0036] Message 4 (Msg4): refers to the fourth downlink message in the UE random access procedure, which is sent by the network side through the physical downlink shared channel. Its RRC layer message entity is RRC Setup.

[0037] The 3GPP TSG RAN WG1 #120 meeting discussed methods for enhancing downlink coverage at the Msg4 PDSCH link level. Section 11 of the meeting's output document R1-2500042 contains the following conclusions:

[0038] For Msg4 PDSCH repetition support, RAN1 to consider:

[0039] Option 1: UE specific repetition indication via DCI

[0040] Option 2: Msg4 repetition is configured by SIB1

[0041] Option 3: Msg4 PDSCH repetition is implicitly determined by SIB1PDSCH repetition.

[0042] In other words, to support repeated transmission of Msg4 PDSCH, RAN1 considers three options:

[0043] Option 1: Indicate the number of repeated transmissions for a specific UE via DCI;

[0044] Option 2: Configure the number of repeated transmissions of Msg4 via SIB1;

[0045] Option 3: Implicitly indicate the number of times Msg4 PDSCH is repeated by the number of times SIB1 PDSCH is repeated.

[0046] In section 2.2 of document R1-2500042, the main proposals supporting these agreements are as follows:

[0047] One is the number of times the UE requests Msg4 PDSCH via Msg3 PUSCH or PRACH:

[0048] a. Huawei and Spreadtrum emphasize the importance of enabling UE to request Msg4 PDSCH repetitions through Msg3 PUSCH or PRACH.

[0049] b. CATT puts forward a method for UEs to request repetitioncapabilities via a 1-bit marker in Msg3.

[0050] Secondly, it indicates the number of repeated transmissions for a specific UE via DCI:

[0051] a. Spreadtrum specifically suggests having Msg4 PDSCH repetitionnumbers as either 2 or 4, and recommends indicating this through DCI.

[0052] b. Samsung, Lenovo, and CCU also recommend utilizing systeminformation or existing fields in DCI to indicate repetitions.

[0053] Thirdly, the number of repeated transmissions of Msg4 is configured via SIB1:

[0054] a. CMCC, Vivo, and other companies, advocate using SIB to indicateenabling / disabling Msg4 PDSCH repetitions and detailing the repetition factor.

[0055] b. Samsung, Lenovo, and CCU also recommend utilizing systeminformation or existing fields in DCI to indicate repetitions.

[0056] Fourthly, the number of repeated transmissions of Msg4 PDSCH is implicitly indicated by the number of repeated transmissions of SIB1 PDSCH:

[0057] a. ZTE and Panasonic propose using the repetition number for PDSCH with SIB1 to implicitly indicate the repetition number for PDSCH with Msg4, thus reducing signaling overhead.

[0058] In summary, the three options present a dilemma in balancing air interface signaling overhead and configuration flexibility: relying solely on DCI results in high signaling overhead, while relying solely on SIB1 or implicit indications sacrifices the flexibility of coverage enhancement for individual UEs (especially those with weak coverage at the beam edge).

[0059] In addition, while the relevant technologies can balance signaling overhead and flexibility to achieve downlink coverage enhancement of Msg4 PDSCH based on 5G NTN, there is room for optimization if there are necessary steps for configuration via SIB signaling.

[0060] To address the aforementioned issues, this application provides relevant solutions, which are detailed below.

[0061] According to an embodiment of this application, a method embodiment for downlink coverage enhancement and optimization based on a 5G non-terrestrial network is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0062] Figure 1 This is a flowchart of a downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application. The method is applied to terminal devices located in a 5G non-terrestrial network, such as... Figure 1 As shown, the method includes the following steps:

[0063] Step S102: Obtain the channel quality measurement value of the downlink reference signal.

[0064] In step S102, the terminal device detects the current downlink channel state in real time to assess the quality of the received signal. Specifically, the terminal device receives a downlink reference signal from the 5G NTN network side (such as a satellite base station or relay node). The downlink reference signal can be a Synchronization Signal Block (SSB), a Channel State Information Reference Signal (CSI-RS), or other signals used for channel measurement. The terminal device performs physical layer measurements on the received downlink reference signal and extracts measurement indicators reflecting channel quality. Channel quality measurements may include, but are not limited to: Reference Signal Received Power (RSRP): representing the average power of the received signal, directly reflecting the signal strength; Reference Signal Received Quality (RSRQ): representing the quality of the received signal, comprehensively considering signal strength and interference noise; Signal-to-Noise Ratio (SNR) or Signal-to-Interference-plus-Noise Ratio (SINR): representing the ratio of useful signal power to noise and interference power.

[0065] Step S104: If the channel quality measurement value is not greater than the first preset threshold, a request message is sent to the network side via message 3. The request message is used to request a new number of retransmissions. The new number of retransmissions is greater than the preset number of retransmissions. Both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel. The preset number of retransmissions is the default number of retransmissions preset by the terminal device and the network side in a non-broadcast manner. The preset number of retransmissions on the terminal device and the preset number of retransmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block.

[0066] In step S104, the terminal device compares the channel quality measurement value obtained in step S102 with a first preset threshold stored locally. If the channel quality measurement value is greater than the first preset threshold, it indicates that the current downlink channel quality is good, and the terminal device can directly receive Msg4 using the preset number of retransmissions without initiating an additional retransmission negotiation process. If the channel quality measurement value is not greater than the first preset threshold (i.e., less than or equal to the threshold), it indicates that the current downlink channel quality is poor, and there may be a risk of coverage blind spots or insufficient link budget. The terminal device then enters the coverage enhancement request process.

[0067] To correctly understand the parameter relationships in this step, the following definitions need to be clarified: Preset number of repeated transmissions: The default number of Msg4 PDSCH repeated transmissions that the terminal device and the network side will pre-set collaboratively in a non-broadcast manner.

[0068] Unlike related technologies that use system information blocks to broadcast configurations, this application employs a pre-configured optimization strategy. That is, the terminal device's internal memory pre-configures the default value (e.g., set twice), and the same default value is also pre-configured (e.g., set twice) in the configuration database of the network-side base station.

[0069] The key point is that the preset number of repeated transmissions within the terminal device is exactly the same as the preset number of repeated transmissions within the network-side device, and the configuration does not depend on the broadcast signaling of the system information block. This pre-configured end-to-end coordination ensures that even without dynamic interaction between the two parties (such as not receiving a DCI instruction or not sending a Msg3 request), both parties can parse Msg4 based on the same default value, thereby significantly reducing SIB signaling overhead while ensuring basic communication reliability.

[0070] New number of retransmissions: The number of Msg4 PDSCH retransmissions requested when the terminal device determines that the channel quality is poor.

[0071] Size relation: The new number of retransmissions must be greater than the preset number of retransmissions. For example, if the preset number of retransmissions is 2, the new number of retransmissions can be 4, 8 or higher, in order to enhance downlink coverage through time diversity gain.

[0072] Value range: The new number of repeated transmissions can be a value in a predefined set (such as {4,8}), and the specific value depends on the buffering capacity, processing capacity of the terminal device, and the resource scheduling strategy of the network side.

[0073] When the above-mentioned judgment condition (channel quality ≤ first preset threshold) is triggered, the terminal device performs the following operation: The terminal device carries request information in the third message of the random access procedure (RRC Connection Setup Request or RRC Connection Resume Request). The request information can be a 1-bit marker / indicator. For example, when the 1-bit marker is "1", it indicates that the terminal device requests a new number of retransmissions (i.e., more than a preset value, such as 4 or 8 times); when the 1-bit marker is "0", it indicates that the terminal device requests to maintain the preset number of retransmissions (although this request is usually not sent in scenarios with good channel quality, it can be used for explicit confirmation in some implementations). The terminal device sends Msg3 containing the request information to the network side via the uplink shared channel.

[0074] On the other hand, if the channel quality measurement value is greater than the first preset threshold, message 4 in the physical downlink shared channel is received based on the preset number of repeated transmissions.

[0075] Understandably, if the channel quality measurement value is greater than the first preset threshold, it indicates that the downlink channel quality of the terminal device is currently good, the link budget is sufficient, and it can meet the reliability requirements of receiving message 4 based on the preset number of retransmissions. In this case, the terminal device does not need to initiate an additional retransmission number negotiation process; it directly performs blind detection and demodulation on message 4 scheduled in the physical downlink shared channel based on the preset number of retransmissions pre-set by the terminal device and the network side. This processing method allows terminals in good channel coverage areas (such as beam centers) to skip complex measurement reporting and DCI dynamic negotiation steps and directly complete the access process using the default configuration. This not only significantly reduces the processing power consumption and computational complexity on the terminal side, avoiding resource waste caused by frequent measurement and signaling interactions, but also reduces the signaling overhead of uplink message 3 and the dynamic scheduling burden of downlink DCI. Therefore, while ensuring access reliability, it maximizes the efficiency of air interface resource utilization and reduces the overall latency of random access.

[0076] The above steps S102 to S104 have the following technical effects.

[0077] By pre-setting the same preset number of Msg4 PDSCH repetitions between the terminal device and the network before communication, the reliance on broadcasting configuration parameters for Msg4 repetition is fundamentally eliminated. In related 5G NTN technologies, the number of repetitions needs to be indicated via SIB broadcasting, which increases downlink control signaling overhead and limits configuration flexibility. In this application, since both the terminal and the device have the same preset default value, they can directly transmit and demodulate Msg4 based on this preset number of repetitions without additional signaling interaction. This mechanism significantly simplifies the system configuration process and saves valuable air interface resources. Especially for terminals located at the beam center or with good channel quality that do not require additional coverage enhancement, no additional negotiation process is needed; the preset value can be used directly, thus minimizing signaling overhead.

[0078] In scenarios with poor channel quality, step S102 obtains the channel quality measurement value of the real-time downlink reference signal, enabling the terminal to accurately perceive the current link status, rather than relying on static or outdated configurations. When the measurement value is not greater than a first preset threshold, it indicates that the current channel conditions are insufficient to support successful reception of Msg4 with a preset number of retransmissions. At this time, the terminal sends a request in message 3 through step S104, requesting a new number of retransmissions greater than the preset value. This on-demand enhancement mechanism based on real-time channel quality ensures that only edge terminals that truly need coverage enhancement will trigger additional resource requests, avoiding resource waste caused by a uniformly high number of retransmissions across the entire network. Through the lightweight request in Msg3, the terminal conveys its coverage requirements to the network side with extremely low signaling cost, enabling the network side to dynamically allocate more time resources for retransmissions for users with weak coverage, thereby effectively improving the success rate of random access in weak coverage scenarios.

[0079] Furthermore, the new number of repeated transmissions exceeds the preset number, ensuring the clarity of the coverage enhancement direction. Upon receiving the request, the network side can, based on the current resource load, use reserved bits in the DCI scheduling of Msg4 to ultimately confirm the specific number of repetitions. This leverages the terminal's agility in sensing channel changes while retaining the network's control over global resource optimization, thus achieving the optimal balance between system performance and user experience in the complex environment of high latency and large coverage in 5G NTN.

[0080] The following are Figure 1 The steps shown are illustrated and explained by way of example.

[0081] In some optional embodiments of this application, the preset number of repeated transmissions is preset by at least one of the following methods:

[0082] The following methods can be used: using the default number of repetitions for Msg4 PDSCH as specified in the standard protocol; using operator-customized parameters in non-volatile memory; using the number of repetitions pre-configured by the manufacturer; or using pre-stored configuration parameters stored in a general-purpose integrated circuit card.

[0083] Specifically, the preset number of repeated transmissions can be configured through the following steps:

[0084] Obtain the access category identifier of the terminal device, wherein the access category identifier is an identifier that represents the access type of the terminal device, determined based on the subscription information stored in the integrated circuit card of the terminal device, and the value of the access category identifier includes local subscription category, roaming subscription category, and restricted access category;

[0085] Based on the access category identifier, a target configuration source is determined from multiple configuration sources, wherein when the access category identifier is the local subscription category, the target configuration source is the integrated circuit card; when the access category identifier is the roaming subscription category, the target configuration source is the non-volatile memory of the terminal device; and when the access category identifier is the restricted access category, the target configuration source is the pre-configured coverage parameters.

[0086] Configuration data is extracted from the target configuration source, and a preset number of repeated transmissions is determined based on the configuration data. It's worth explaining that the setup in this embodiment is as follows: before the terminal device receives the Msg4 PDSCH, the terminal's access category is determined based on the subscription information already present in the terminal device's integrated circuit card, which can be read locally without network interaction. Then, based on the access category, the number of repeated transmissions is obtained from three configuration sources with different levels of reliability and adaptability. The reason for using the integrated circuit card subscription information as the determination basis is that the reception of Msg4 occurs before the terminal completes authentication with the network. At this time, the terminal cannot obtain the dedicated configuration from the network side and must rely on information that can be determined locally before access to make the determination, thereby ensuring that the sending and receiving sides have a consistent understanding of the number of repeated transmissions.

[0087] For terminals with local subscriptions, their home network is the same as their current registered network. The home operator can pre-write the number of repetitions optimized for the coverage characteristics of their local network into the integrated circuit card (ICC), making the ICC the most accurate configuration source. For terminals with roaming subscriptions, their home operator cannot predict the coverage characteristics of the accessed network, rendering the local network parameters in the ICC inapplicable. Therefore, operator-customized parameters stored in the terminal's non-volatile memory, which adapt to different accessed networks, are used as the configuration source. For terminals with restricted access, due to the lack of available subscription-side or customized-side configurations, pre-configured coverage parameters are used as a fallback to determine the number of repetitions while meeting the minimum random access success rate.

[0088] Optionally, extracting configuration data from the target configuration source and determining a preset number of repeated transmissions based on the configuration data includes:

[0089] When the target configuration source is the non-volatile memory, the second configuration parameter stored in the non-volatile memory is extracted, and the second configuration parameter is determined as the preset number of repeated transmissions; wherein, the second configuration parameter is determined by the following steps: obtaining the operator identifier stored in the non-volatile memory of the terminal device that corresponds to the access network where the terminal device resides; according to the operator identifier, searching in the non-volatile memory for a repeated transmission configuration item corresponding to the operator identifier, and determining the number of repetitions indicated by the repeated transmission configuration item as the second configuration parameter.

[0090] When the target configuration source is the pre-configured coverage parameters, the preset number of repeated transmissions is determined based on the pre-configured coverage parameters, wherein the pre-configured coverage parameters are the number of repeated transmissions corresponding to satisfying a preset random access success rate. It should be noted that when the target configuration source is a non-volatile memory, it corresponds to a roaming subscription category terminal. Its second configuration parameter is determined based on the access network it resides in: first, the operator identifier corresponding to the current access network is obtained from the memory; then, the identifier is used to find the corresponding repeated transmission configuration item, and the number of repetitions indicated by it is used as the second configuration parameter. Thus, the terminal can obtain its own suitable value under different access networks.

[0091] Finally, when the target configuration source is a pre-configured coverage parameter, it corresponds to a terminal in a restricted access category. Due to the lack of available contract-side or customized configurations, a fallback coverage parameter is used. This parameter is defined as the number of repetitions required to meet the preset minimum random access success rate, ensuring access reliability in abnormal situations.

[0092] According to some optional embodiments of this application, after sending the request information to the network side via message 3, the following steps can also be performed: receiving the response information sent by the network side in response to the request information, wherein the response information includes at least: a first number of repeated transmissions; the first number of repeated transmissions is determined by the network side based on the network side's resource load index, the resource load index being used to quantitatively characterize the occupancy of downlink transmission resources; the first number of repeated transmissions determined when the value of the resource load index is greater than a second preset threshold is less than or equal to the first number of repeated transmissions determined when the value of the resource load index is not greater than the second preset threshold.

[0093] Optionally, the response information is carried in the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

[0094] In this embodiment, after the terminal device sends a request message containing a request for repeated transmission counts to the network side via message 3, it can also receive a response message from the network side in response to the request message. The response message includes at least a first number of repeated transmission counts, which is dynamically determined by the network side based on its own resource load indicators. Resource load indicators are used to quantitatively characterize the occupancy of downlink transmission resources, and can be reflected, for example, through indicators such as the utilization rate of physical downlink shared channel resource blocks, scheduling request queue length, or system throughput.

[0095] After receiving a request from a terminal device, the network side comprehensively assesses the current resource load to determine the final number of Msg4 PDSCH retransmissions allocated to the terminal device, thereby achieving a balance between meeting terminal coverage requirements and ensuring overall system resource efficiency.

[0096] Specifically, the first number of repeated transmissions determined by the network side is negatively or non-linearly correlated with the resource load index. When the resource load index is greater than the second preset threshold, it indicates that the current downlink transmission resources are relatively tight. In order to save resources to serve more users or ensure the quality of other services, the network side will determine a smaller number of first repeated transmissions. For example, it may only support a lower number of repetitions (such as 2 or 4 times), or it may even refuse to increase the number of repetitions and suggest that the terminal use the preset default value.

[0097] Conversely, when the resource load index value is not greater than the second preset threshold, it indicates that downlink transmission resources are relatively abundant, and the network side has the ability to provide more time resources for coverage enhancement. In this case, the determined first number of repeated transmissions is relatively large, for example, it may be the maximum value requested by the terminal (such as 8 times), to ensure that terminals at the edge of weak coverage can successfully receive Msg4. This embodiment enables the network side to flexibly respond to access requirements under different load scenarios, avoiding system performance degradation due to excessive allocation of repeated resources when resources are overloaded, or wasting coverage enhancement opportunities due to conservative configuration when resources are idle.

[0098] In one alternative implementation, the response information is carried in the reserved bits of the downlink control information in scheduling message 4. Specifically, the reserved bits may include one bit. One bit is used to indicate the first retransmission count finally determined by the network side. For example, this 1-bit field can be mapped to two different retransmission count options, such as "0" indicating that the first retransmission count is 4 times, and "1" indicating that the first retransmission count is 8 times (assuming the default value is 2 times, and the terminal requests a higher number of times).

[0099] Since the terminal has already initiated the request via a 1-bit field in Msg3, the network side does not need to transmit a large amount of repetition count information in the DCI. It only needs to use this 1-bit reserved bit to indicate the final confirmed repetition count level. This greatly saves the signaling overhead of the DCI, enabling fine-grained dynamic scheduling of the Msg4 repetition count without increasing the control channel burden. This satisfies both the terminal's need for enhanced coverage and the high requirements of the 5G NTN system for air interface resource efficiency. After receiving the DCI carrying this reserved bit, the terminal device parses out the first repetition count and configures its PDSCH receive window accordingly for blind detection and demodulation of Msg4.

[0100] In summary, this embodiment dynamically adjusts the Msg4 repetition count by combining resource load indicators and uses a single-bit reserved field in the DCI for indication. This effectively balances system resource overhead while ensuring the success rate of weak coverage terminal access, achieving a unity of coverage enhancement and efficient resource utilization.

[0101] According to some alternative embodiments of this application, before obtaining the channel quality measurement value of the downlink reference signal, the following steps may also be performed: determining the coverage location type of the terminal device relative to the downlink transmission beam, wherein the coverage location type includes the beam center region and the beam edge region.

[0102] The channel quality measurement of the downlink reference signal can be obtained by the following method: when the coverage location type is a beam edge region, the channel quality measurement of the downlink reference signal can be obtained.

[0103] On the other hand, when the coverage location type is the beam center area, message 4 in the physical downlink shared channel is received based on a preset number of repeated transmissions.

[0104] In this embodiment, the terminal device determines its coverage location type relative to the downlink transmission beam by parsing the beam identifier in the downlink reference signal or based on pre-configured beam geometry attributes. The coverage location type is mainly divided into beam center region and beam edge region. The beam center region refers to the core area with high signal strength and low interference within the beam coverage area, while the beam edge region refers to the boundary area of ​​the beam coverage area, typically accompanied by greater path loss and poorer channel conditions. By pre-distinguishing between these two location types, the terminal device can adopt differentiated processing strategies based on the typical channel characteristics of its location, thereby optimizing the resource consumption and latency of the random access procedure.

[0105] For example, if the channel quality measurement value of the reference signal associated with the downlink transmit beam is greater than a preset threshold, the coverage location type is the beam center region; if the channel quality measurement value of the reference signal associated with the downlink transmit beam is not greater than the preset threshold, the coverage location type is the beam edge region.

[0106] Based on the determined coverage location type, the terminal device performs differentiated channel quality measurements and Msg4 reception strategies. When the terminal device determines that its coverage location type is a beam edge area, since users in this area face a higher risk of access failure, the terminal device performs a step to obtain the channel quality measurement value of the downlink reference signal to accurately assess the current instantaneous channel condition and determine whether to trigger the subsequent retransmission request process. This mechanism ensures that terminals in edge areas can make accurate coverage enhancement decisions based on real-time channel measurement data. Conversely, when the terminal device determines that its coverage location type is a beam center area, considering that this area usually has good default coverage capabilities, the terminal device does not need to perform time-consuming channel quality measurements and subsequent Msg3 request interaction processes, but directly receives message 4 in the physical downlink shared channel based on a pre-set preset number of retransmissions.

[0107] It should be noted that when the coverage location type is the beam center area, the terminal device skips the steps of acquiring channel quality measurements and subsequent transmission request information. The terminal device directly receives message 4 in the physical downlink shared channel based on a preset number of retransmissions.

[0108] Understandably, for terminals located in the beam center area, skipping the channel quality measurement and Msg3 request steps and directly receiving Msg4 using a preset number of repetitions not only reduces terminal-side computational power consumption and processing latency but also avoids unnecessary uplink signaling (Msg3) transmission, thereby reducing uplink resource overhead. Simultaneously, since the number of users in the beam center area is typically large, this simplified process helps alleviate the pressure on the network side to handle a large number of access requests. For terminals located in the beam edge area, the complete channel measurement and request process is retained, ensuring they can obtain the necessary coverage enhancement based on actual channel conditions. In the high-latency, large-coverage scenario of 5G NTN, the above steps achieve the optimal balance between coverage reliability and overall system resource utilization.

[0109] In some optional embodiments of this application, the request information is carried in at least one of the following: the media access control unit of message 3, the information element in the radio resource control message carried by the physical uplink shared channel of message 3, and the preset bit field in message 3, wherein the preset bit field includes: one bit.

[0110] The request information can be carried in the Media Access Control Unit (MAC CE) of message 3, explicitly instructing the terminal device to request a new number of retransmissions via MAC layer signaling. Alternatively, the request information can also be carried in the Information Element (IE) of the Radio Resource Control (RRC) message carried in message 3, using RRC layer signaling to make a configuration request. Furthermore, to further simplify the signaling structure and reduce overhead, the request information can also be directly carried in a preset bit field in message 3. In this embodiment, the preset bit field includes only one bit (1-bit). When this 1-bit field is set to a specific value (e.g., "1"), it indicates that the terminal device requests a new number of retransmissions; when the field is another specific value (e.g., "0"), it indicates that the terminal device does not request a new number of retransmissions or requests to maintain the preset number of retransmissions. This design, which embeds the request information into the existing Msg3 signaling structure, allows terminal devices to efficiently and lightweightly convey their coverage enhancement needs without establishing a dedicated signaling channel or adding additional signaling messages, provided that the network side already knows the Msg3 content. This ensures reliable signaling interaction while maximizing the saving of air interface resources.

[0111] In one optional embodiment, the request information further includes auxiliary information, which includes at least one of the following: the elevation angle of the terminal device relative to the serving satellite, the distance between the terminal device and the serving satellite, and the location information of the terminal device; the auxiliary information is used to enable the network side to determine the new number of repetitions.

[0112] Specifically, auxiliary information is used to help the network side more accurately determine the final number of new repeat transmissions, or to help the network side assess the coverage status of terminal devices to optimize resource scheduling. Auxiliary information includes at least one of the following:

[0113] The elevation angle of a terminal device relative to the serving satellite refers to the angle between the zenith direction of the terminal device's location and the direction of the serving satellite's location. The terminal device can obtain its latitude and longitude coordinates through the Global Navigation Satellite System (GNSS) and combine this with ephemeris data of the serving satellite obtained from downlink reference signals or system information to calculate its relative geometric position to the serving satellite at the current moment, thus determining its elevation angle. The elevation angle is one of the key factors determining the 5G NTN link budget. A low elevation angle typically means that the signal travels a longer atmospheric path and a more complex propagation environment, potentially leading to greater path loss and multipath effects. The network side can use the elevation angle information to determine whether the terminal is in an area susceptible to interference or high loss, thereby helping to determine whether to increase the number of Msg4 repetitions.

[0114] The distance between the terminal device and the serving satellite refers to the instantaneous geometric distance (slant range) between them. Similarly, the terminal device can calculate this distance using positioning information and ephemeris data from the serving satellite. Distance directly determines the magnitude of free-space path loss. In 5G NTN systems, due to different satellite orbital altitudes (e.g., LEO, MEO, GEO), distance variations significantly impact signal strength. The network side can accurately estimate the current path loss model based on distance information, thereby more precisely allocating the number of Msg4 retransmissions. This avoids over-configuring retransmissions for nearby terminals, preventing resource waste, or under-configuring retransmissions for distant terminals, leading to access failures.

[0115] Location information of the terminal device can include its absolute geographic coordinates (such as latitude, longitude, and altitude), or its cell ID or beam ID. If it's absolute geographic coordinates, the network side can combine this with satellite orbit information to construct a more accurate link budget model. If it's a cell or beam ID, the network side can directly query pre-set beam coverage maps or historical statistics to understand the approximate coverage characteristics of the beam's center and edges, thus aiding decision-making. For example, if the location information reported by the terminal indicates that it is located in the edge region of a certain beam, the network side may tend to allocate a higher number of repeated transmissions.

[0116] When a terminal device sends a request message to the network via Msg3, in addition to carrying a flag indicating that the request should be repeated an additional time, it may also carry at least one of the aforementioned auxiliary information. Upon receiving the Msg3, the network performs the following processing logic:

[0117] The network side not only refers to channel quality measurements (such as RSRP) reported by terminal devices, but also combines received auxiliary information (such as elevation angle, distance, or location) for a comprehensive evaluation. The network side can construct or revise the link budget model based on the auxiliary information to calculate the maximum redundancy required for the current link. Alternatively, the network side can look up the corresponding recommended repetition count in a pre-defined mapping table based on the auxiliary information. For example, the pre-defined table may specify a set of recommended repetition counts for different elevation angle or distance intervals.

[0118] After determining the candidate number of new retransmissions, the network side will also make a final decision based on the current resource load (such as the utilization rate of PDSCH resource blocks). If the resource load is low, the network side may tend to allocate a larger number of retransmissions (such as 8 times) to ensure high-reliability access. If the resource load is high, the network side can judge the actual needs of the terminal based on auxiliary information and allocate a compromise number of retransmissions (such as 4 times), or if the auxiliary information indicates that the terminal is under extremely adverse conditions (such as extremely low elevation angle or extremely long distance), the network side will prioritize the access of the terminal even if the load is high. The final determined number of new retransmissions will be encapsulated in the downlink control information (DCI) of the scheduling Msg4 and sent to the terminal device through reserved bits.

[0119] Introducing auxiliary information allows the network to go beyond a single RSRP measurement and gain a more comprehensive understanding of the terminal's coverage status from a spatial geometric perspective. This helps the network make fairer and more accurate coverage enhancement decisions when resources are limited, thereby improving the success rate of edge user access while maximizing the overall system resource utilization efficiency.

[0120] This application embodiment also provides a downlink coverage enhancement and optimization method based on a 5G non-terrestrial network, applied to a 5G non-terrestrial network, including the following steps: receiving a request information sent by a terminal device through message 3, wherein the request information is sent by the terminal device when the channel quality measurement value of the downlink reference signal is not greater than a first preset threshold; the request information is used to request a new number of retransmissions; the new number of retransmissions is greater than a preset number of retransmissions; both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel; the preset number of retransmissions is the number of retransmissions preset by the 5G non-terrestrial network and the terminal device before communication, and the preset number of retransmissions in the 5G non-terrestrial network is the same as the preset number of retransmissions in the terminal device; determining a first number of retransmissions according to a resource load index, wherein the resource load index is used to quantify the occupancy of downlink transmission resources; the first number of retransmissions is greater than or equal to the new number of retransmissions; sending a response information to the terminal device, wherein the response information includes at least the first number of retransmissions.

[0121] Furthermore, the first number of repeated transmissions determined when the value of the resource load index is greater than the second preset threshold is less than or equal to the first number of repeated transmissions determined when the value of the resource load index is not greater than the second preset threshold.

[0122] Furthermore, the response information is carried by the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

[0123] Figure 2 This is a flowchart of a downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application. The method is applied to terminal devices located in a 5G non-terrestrial network, such as... Figure 2 As shown, the method includes the following steps:

[0124] Step S202: Obtain the channel quality measurement value of the downlink reference signal.

[0125] Specifically, the terminal device acquires channel quality measurements of the downlink reference signal. These channel quality measurements can be either the received power or the received quality of the reference signal, reflecting the wireless channel conditions at the terminal device's current location. By measuring the downlink reference signal in real time, the terminal device can perceive the path loss and interference levels between the satellite and the terminal.

[0126] Step S204: Among multiple preset channel quality measurement threshold intervals, determine the target preset channel quality measurement threshold interval in which the channel quality measurement value is located.

[0127] In step S204, the terminal device determines the target preset channel quality measurement threshold interval containing the currently acquired channel quality measurement value from multiple preset channel quality measurement threshold intervals. These preset channel quality measurement threshold intervals are pre-configured within the terminal device, dividing the continuous channel quality range into several discrete intervals, each representing a specific channel condition level. For example, channel quality can be divided into several intervals such as "Excellent," "Good," "Medium," and "Poor," or multiple threshold points can be set based on a specific numerical range. By comparing the measured value with these preset thresholds, the terminal device locates the unique corresponding interval, thereby quantizing the continuous analog signal into discrete channel state information, simplifying subsequent processing logic.

[0128] Step S206: Among multiple preset repeated transmission counts, determine the target preset repeated transmission count corresponding to the target preset channel quality measurement threshold range, wherein the preset repeated transmission count is the number of times the same message 4 is repeatedly transmitted in the physical downlink shared channel.

[0129] In step S206, the terminal device determines the target preset retransmission count corresponding to the aforementioned target preset channel quality measurement threshold interval from among multiple preset retransmission counts. The preset retransmission count refers to the number of times the same Msg4 message is repeatedly transmitted in the physical downlink shared channel; for example, the preset set may include 2, 4, and 8 times. Through a pre-established "channel quality interval - retransmission count" mapping table, the terminal device can directly look up the required retransmission count based on the current channel quality interval. For example, if the current channel quality is in a poor interval, a larger retransmission count, such as 8 times, is mapped to ensure the reliability of message reception; if it is in a better interval, a smaller retransmission count, such as 2 times, is mapped to save resources. This mapping mechanism allows the terminal device to quickly determine a reasonable coverage enhancement level based on historical experience or standard specifications without performing complex link budget calculations.

[0130] Step S208: Send a request message to the network side via message 3, wherein the request message includes at least the target preset number of repeated transmissions.

[0131] In step S208, the terminal device sends a request message to the network side via message 3 (Msg3), which includes at least the predetermined target number of repeated transmissions. In this way, the terminal device explicitly informs the network side of its coverage enhancement requirements derived from channel quality assessment. Upon receiving the request, the network side can confirm or adjust the requested number of repetitions based on current resource load, scheduling strategies, and other factors, and indicate the final number of repeated transmissions in the subsequent downlink control information of scheduling Msg4. This threshold-mapping-based request method reflects the terminal device's autonomous awareness of the channel environment and provides the network side with a clear optimization target, helping to achieve more accurate and efficient downlink coverage enhancement and resource scheduling in 5G NTN scenarios with high latency and large coverage.

[0132] The above steps quantify continuous channel quality into discrete threshold intervals and map them to specific number of repeated transmissions, forming a standardized coverage enhancement request mechanism. The technical benefits it brings are mainly reflected in the following aspects.

[0133] First, it significantly reduces the processing complexity and decision-making latency of terminal devices. By employing a preset channel quality threshold range-repeated transmission count mapping table, terminal devices do not need to perform complex real-time link budget calculations or probability model derivations. They can quickly determine the required number of repetitions simply by comparing the measured value with the preset threshold and looking up the table. This simplified decision-making logic is particularly suitable for mobile terminals with limited resources or processing power, accelerating the generation speed of Msg3 in the random access procedure, thereby reducing overall access latency.

[0134] Secondly, it enables a more refined and standardized expression of coverage enhancement requirements. Compared to the single-bit request mechanism, the multi-threshold range mapping mechanism allows terminals to request a more suitable number of repetitions (e.g., 2, 4, 8, etc.) based on subtle differences in channel quality. This allows the network side to receive more accurate coverage requirement information, avoiding resource waste (e.g., requesting the maximum number of repetitions despite a good channel) or access failures (e.g., requesting the minimum number of repetitions despite a poor channel) caused by overly coarse information granularity, thereby improving the accuracy and effectiveness of coverage enhancement.

[0135] Furthermore, it helps balance system resource utilization with user access experience. Through preset threshold ranges, the allocation of repetition counts between the network and terminal sides is predictable. When a terminal reports a target preset number of repetitions, the network side can make more flexible scheduling decisions based on this specific value and current resource load indicators. For example, when resources are scarce, the network side can prioritize requests with low repetition counts, or make trade-off adjustments to requests in the DCI based on load conditions; while when resources are abundant, it can fully satisfy high-repetition-count requests from terminals. This mechanism retains the flexibility of terminals to initiate requests autonomously based on channel quality, while providing the network side with a clear basis for resource allocation, achieving end-to-end resource optimization.

[0136] Finally, robustness in complex channel environments outside of terrestrial networks is enhanced. In 5G NTN scenarios, channel quality varies drastically and is unevenly distributed due to satellite movement and high path loss. Preset threshold ranges can be specifically optimized based on factors such as satellite orbit characteristics and beam coverage (e.g., setting stricter thresholds for beam edge regions to trigger high-repetition-count requests). This adaptive mechanism based on preset rules enables terminals to make reasonable coverage enhancement decisions based on locally pre-configured information even in the absence of precise real-time network-side scheduling instructions. This increases the probability of successful access in weak coverage areas while reducing request deviations caused by channel estimation errors.

[0137] In some optional embodiments of this application, after sending the request information to the network side via message 3, the following steps can also be performed: receiving the response information sent by the network side in response to the request information, wherein the response information includes at least: a second number of repeated transmissions; the second number of repeated transmissions is determined by the network side based on the network side's resource load index, the resource load index being used to quantitatively characterize the occupancy of downlink transmission resources; the second number of repeated transmissions determined when the value of the resource load index is greater than a third preset threshold is less than or equal to the second number of repeated transmissions determined when the value of the resource load index is not greater than the third preset threshold.

[0138] Optionally, the response information is carried in the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

[0139] In this embodiment, the terminal device receives a response from the network side based on its request information. This response information includes at least a second number of retransmissions determined by the network side. This second number of retransmissions is not directly the number requested by the terminal, but rather a value dynamically determined by the network side based on its current resource load. Resource load indicators are used to quantify the occupancy of downlink transmission resources; for example, they can be reflected by indicators such as the utilization rate of physical downlink shared channel resource blocks, scheduling request queue length, or system throughput. After receiving the terminal's request, the network side comprehensively evaluates the current resource load to determine the final number of Msg4 PDSCH retransmissions allocated to the terminal, thereby achieving a balance between meeting the terminal's coverage requirements and ensuring overall system resource efficiency.

[0140] The second retransmission count is negatively or non-linearly correlated with the resource load metric. When the resource load metric exceeds the third preset threshold, it indicates that downlink transmission resources are strained. To conserve resources and serve more users or ensure the quality of other services, the network will determine a smaller or lower second retransmission count. Conversely, when the resource load metric is below the third preset threshold, it indicates that downlink transmission resources are relatively abundant. The network has the capacity to provide more time for coverage enhancement, and the determined second retransmission count is larger, potentially equal to or close to the target preset retransmission count requested by the terminal. This dynamic adjustment mechanism based on resource load allows the network to flexibly respond to access demands under different load scenarios, avoiding system performance degradation due to excessive allocation of retransmission resources during resource overload, or wasting coverage enhancement opportunities due to conservative configuration during resource idle periods.

[0141] Furthermore, to further reduce control signaling overhead, the response information can be carried in the reserved bits of the downlink control information in scheduling message 4. Specifically, this reserved bit can include one bit (1-bit). This one bit is used to indicate the second repetition number finally determined by the network side. For example, this 1-bit field can be mapped to two different repetition number options, such as "0" indicating a lower value for the second repetition number (e.g., 2 or 4 times), and "1" indicating a higher value for the second repetition number (e.g., 4 or 8 times). Since the terminal has already initiated the request through the preset mapping mechanism in Msg3, the network side does not need to transmit a large amount of repetition number information in DCI, and only needs to use this 1-bit reserved bit to indicate the finally confirmed repetition number level. This design greatly saves the signaling overhead of DCI, enabling fine-grained dynamic scheduling of Msg4 repetition number without increasing the burden on the control channel. This satisfies both the terminal's need for enhanced coverage and the high requirements of the 5G NTN system for air interface resource efficiency. After receiving the DCI carrying the reserved bit, the terminal device parses out the second repeated transmission number and configures its PDSCH receiving window accordingly to perform blind detection and demodulation of Msg4.

[0142] This application also provides a downlink coverage enhancement and optimization method based on a 5G non-terrestrial network, applied to a 5G non-terrestrial network, comprising the following steps: receiving a request information sent by a terminal device via message 3, wherein the request information is used to request a second target number of retransmissions; the second target number of retransmissions is the number of retransmissions corresponding to a target preset channel quality measurement threshold interval among multiple preset number of retransmissions; the target preset channel quality measurement threshold interval is the preset information quality measurement threshold interval in which the channel quality measurement value of the downlink reference signal obtained by the terminal device is located among multiple preset information quality measurement threshold intervals; determining the second number of retransmissions according to a resource load index, wherein the resource load index is used to quantify the occupancy of downlink transmission resources; the second number of retransmissions is greater than or equal to the second target number of retransmissions; sending a response information to the terminal device, wherein the response information includes at least the second number of retransmissions.

[0143] Furthermore, the second repeated transmission count determined when the resource load index value is greater than the third preset threshold is less than or equal to the second repeated transmission count determined when the resource load index value is not greater than the third preset threshold.

[0144] Furthermore, the response information is carried by the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

[0145] Figure 3This is a flowchart of another downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application. Figure 3 This illustrates an implementation method for optional DCI configuration based on channel quality, wherein, Figure 3 The method shown consists of three parts:

[0146] 1. Pre-configuration: The default value of Msg4 PDSCH repetition count is set to 2 in both the UE and the base station. It is worth noting that the key point is that the UE and the base station should coordinate to set the same default value of Msg4 PDSCH repetition count.

[0147] 2. UE autonomously decides whether to initiate negotiation: The UE measures the downlink RSRP. If the channel quality is good, it uses the pre-set default number of repetitions. If the channel quality is poor, the UE reports a request for a new number of repetitions through the 1-bit field of Msg3.

[0148] 3. DCI dynamic configuration completes negotiation: If the base station receives a repetition count request reported by the UE through Msg3, it will use 1 reserved bit in the DCI scheduling Msg4 to notify the UE of the final Msg4 PDSCH repetition count according to the resource load; if the base station does not receive a repetition count request reported by Msg3, it does not need to configure the repetition count through DCI and uses the pre-set default repetition count.

[0149] like Figure 3 As shown, the method includes the following steps.

[0150] Step 1: Set the same default value for the number of Msg4 PDSCH repetitions to 2 within both the UE and the base station;

[0151] Step 2: UE measures RSRP / RSRQ;

[0152] Step 3: The UE judges the channel quality. The UE presets the channel quality threshold and judges the quality of the channel by measuring the RSRP / RSRQ results.

[0153] Step 4: If the channel quality is good, both the UE and the base station use a pre-set 2 times as the Msg4 PDSCH repetition count;

[0154] Step 5: If the channel quality is poor, the UE reports a new number of repetitions through the 1-bit field of Msg3. The requested value is 4 or 8 times. Note that this is greater than the 2 times pre-configured in SIB1.

[0155] Step 6: The access network determines the current resource load.

[0156] Step 7: If the resource load is small, the access network will use 1 bit reserved in the DCI of scheduling Msg4 to notify the UE that the final Msg4 PDSCH repetition count is 4 or 8 times.

[0157] Step 8: If the resource load is large, the access network will use 1 bit reserved in the DCI of scheduling Msg4 to notify the UE that the final Msg4 PDSCH repeats 4 times.

[0158] It should be noted that the above process consists of three parts. The first part is that the UE and the base station pre-set default values. The key is that the default values ​​set by the two are the same and must be selected. The second part is the UE's autonomous decision. The third part is the DCI differential configuration, which is optional. The DCI differential configuration in the third part may not exist. Therefore, it is called the DCI optional configuration implementation method.

[0159] exist Figure 3 In the method shown, the terminal device and the access network are enhanced as follows.

[0160] Terminal device enhancement:

[0161] Supports presetting the number of Msg4 PDSCH repetitions;

[0162] Supports receiving and decoding the Msg4 PDSCH repetition count carried by the DCI;

[0163] Supports deciding whether to use a pre-set number of Msg4 PDSCH repetitions or initiate a new repetition request based on channel quality;

[0164] In cases of poor channel quality, a request for a new number of Msg4 PDSCH repetitions can be reported via the 1-bit field of Msg3.

[0165] Access network enhancement:

[0166] Supports presetting the number of Msg4 PDSCH repetitions;

[0167] Supports notifying the UE of the Msg4 PDSCH repetition count via DCI;

[0168] Supports receiving and decoding the Msg3 reporting request and the Msg4 PDSCH repetition count;

[0169] It supports determining whether to notify the UE of the Msg4 PDSCH repetition count as 4 or 8 times via DCI based on resource load.

[0170] Figure 4 This is a flowchart of another downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application. Figure 4This illustrates an implementation method for optional DCI configurations based on UE location and channel quality, wherein... Figure 4 The method shown consists of three parts:

[0171] 1. Pre-configuration: The default value of Msg4 PDSCH repetition count is set to 2 in both the UE and the base station. It is worth noting that the key point is that the UE and the base station should coordinate to set the same default value of Msg4 PDSCH repetition count.

[0172] 2. (with) Figure 3 (Different) UE autonomously decides whether to initiate negotiation: The UE determines whether it is currently located at the beam center or the beam edge. If it is located at the beam center, it uses the pre-set default number of repetitions; if it is located at the beam edge, it measures RSRP and then decides whether to use the pre-set default number of repetitions or to perform further measurements, judgments, and report requests based on channel quality.

[0173] 3. DCI dynamic configuration completes negotiation: If the base station receives a repetition count request reported by the UE through Msg3, it will use 1 reserved bit in the DCI scheduling Msg4 to notify the UE of the final Msg4 PDSCH repetition count according to the resource load; if the base station does not receive a repetition count request reported by Msg3, it does not need to configure the repetition count through DCI and uses the pre-set default repetition count.

[0174] like Figure 4 As shown, the method includes the following steps.

[0175] Step 1: Set the same default value for the number of Msg4 PDSCH repetitions to 2 within both the UE and the base station;

[0176] Step 2: The UE determines whether it is currently located at the center or edge of the beam;

[0177] Step 3: If the UE is located at the center of the beam, use the pre-set 2 times as the number of Msg4 PDSCH repetitions;

[0178] Step 4: If the UE is located at the beam edge, the UE measures RSRP / RSRQ;

[0179] Step 5: The UE judges the channel quality. The UE presets a channel quality threshold and judges the quality of the channel by measuring the RSRP / RSRQ results.

[0180] Step 6: If the channel quality is good, both the UE and the base station use a pre-set 2 times as the Msg4 PDSCH repetition count;

[0181] Step 7: If the channel quality is poor, the UE reports a new number of repetitions through the 1-bit field of Msg3. The requested value is 4 or 8 times. Note that this is greater than the 2 times pre-configured in SIB1.

[0182] Step 8: The access network determines the current resource load.

[0183] Step 9: If the resource load is small, the access network will use 1 bit reserved in the DCI of scheduling Msg4 to notify the UE that the final Msg4 PDSCH repetition count is 4 or 8 times.

[0184] Step 10: If the resource load is large, the access network will use 1 bit reserved in the DCI of scheduling Msg4 to notify the UE that the final Msg4 PDSCH repeats 4 times.

[0185] It should be noted that, Figure 4 The method shown is the same as Figure 3 The methods shown are all optional DCI configuration implementation methods. Figure 4 The method shown is the same as Figure 3 The difference in the method shown is that the UE side adds a judgment process to determine whether the UE is currently located at the beam center or the beam edge.

[0186] exist Figure 4 In the method shown, the terminal device and the access network are enhanced as follows.

[0187] Terminal device enhancement:

[0188] 1. Supports presetting the number of Msg4 PDSCH repetitions;

[0189] 2. (with) Figure 3 Compared to the method shown, the new feature supports deciding whether to use the pre-set default number of Msg4 PDSCH repetitions or to further measure RSRP / RSRQ based on whether the UE is at the beam center or the beam edge.

[0190] 3. Supports receiving and decoding the Msg4 PDSCH repetition count carried by the DCI;

[0191] 4. Supports deciding whether to use a pre-set number of Msg4 PDSCH repetitions or initiate a new repetition request based on channel quality;

[0192] 5. Supports reporting a new number of Msg4 PDSCH repetitions via the 1-bit field of Msg3 when the channel quality is poor.

[0193] Access network enhancement:

[0194] 1. Supports presetting the number of Msg4 PDSCH repetitions;

[0195] 2. Supports notifying the UE of the Msg4 PDSCH repetition count via DCI;

[0196] 3. Supports receiving and decoding the Msg3 reporting request and the Msg4 PDSCH repetition count;

[0197] 4. Supports determining whether to notify the UE of the Msg4 PDSCH repetition count as 4 or 8 times via DCI based on resource load conditions.

[0198] Figure 5 This is a flowchart of another downlink coverage enhancement and optimization method based on a 5G non-terrestrial network according to an embodiment of this application. Figure 5 This illustrates a mandatory DCI configuration implementation method based on channel quality, wherein... Figure 5 The method shown consists of three parts:

[0199] 1. (with) Figure 3 , 4 (Different from each other) Pre-configuration: The Msg4 PDSCH repetition count set and associated RSRP threshold range are pre-set inside the UE. Note that in this mandatory DCI configuration implementation method, the base station does not need to coordinate with the UE to pre-set the same repetition count set and associated RSRP threshold range data.

[0200] 2. (with) Figure 3 , 4 (All are different) UE measurement and request: The UE measures the downlink RSRP, selects the required number of repetitions according to the threshold, and reports the number of repetitions requested through the 1-bit field of Msg3;

[0201] 3. (with) Figure 3 , 4 (All are different) DCI dynamic configuration completes negotiation: The base station uses reserved bits to notify the final number of Msg4 PDSCH repetitions in the DCI scheduling Msg4 according to the UE request and resource load.

[0202] like Figure 5 As shown, the method includes the following steps.

[0203] Step 1: The UE pre-sets the Msg4 PDSCH repetition count set [2,4,8] and its corresponding RSRP threshold range;

[0204] Step 2: UE measures RSRP / RSRQ;

[0205] Step 3: The UE determines the channel quality and finds the corresponding number of repetitions within the threshold range of Step 1;

[0206] Step 4: The UE reports a new number of repetitions via the 1-bit field of Msg3, with the request value being 2, 4, or 8 times;

[0207] Step 5: The access network determines the current resource load.

[0208] Step 6: If the resource load is small, the access network uses 1 bit reserved in the DCI of scheduling Msg4 to notify the UE of the final Msg4 PDSCH repetition number, biased towards a larger number of 4 or 8 times.

[0209] Step 8: If the resource load is large, the access network will use 1 bit reserved in the DCI of scheduling Msg4 to notify the UE of the final Msg4 PDSCH repetition number, biased towards a smaller number of 2 or 4 times.

[0210] It should be noted that the above process consists of three parts. The first part is that the UE pre-sets the default set of repetition counts and their corresponding channel quality threshold ranges. The second part is that the UE makes its own decision and requests. The third part is DCI differential configuration. Since the UE request and DCI differential configuration are both indispensable, this method is called DCI mandatory configuration.

[0211] exist Figure 5 In the method shown, the terminal device and the access network are enhanced as follows.

[0212] Terminal device enhancement:

[0213] 1. Supports pre-setting the Msg4 PDSCH repetition count set and its corresponding RSRP threshold range;

[0214] 2. Supports receiving and decoding the Msg4 PDSCH repetition count carried by the DCI;

[0215] 3. Supports selecting the corresponding number of repetitions based on the measured RSRP;

[0216] 4. Supports reporting new Msg4 PDSCH repetition counts via the 1-bit field of Msg3.

[0217] Access network enhancement:

[0218] 1. Supports notifying the UE of the Msg4 PDSCH repetition count via DCI;

[0219] 2. Supports receiving and decoding the Msg3 reporting request and the Msg4 PDSCH repetition count;

[0220] 3. Supports determining whether to notify the UE of the Msg4 PDSCH repetition count via DCI is 2, 4, or 8 times based on resource load conditions.

[0221] according to Figures 1 to 5 As shown in the method, this application proposes for the first time a technical solution based on pre-optimized DCI optional configuration to achieve Msg4 PDSCH downlink coverage enhancement. The UE and base station pre-set default repetition counts, and the UE autonomously decides whether to report and request a new repetition count. The DCI method completes the UE-specific configuration of the repetition count. This includes: the UE's autonomous decision to report and request a new repetition count is based on channel quality; the UE's autonomous decision to report and request a new repetition count is based on beam position and channel quality.

[0222] Furthermore, this application proposes for the first time a technical solution based on pre-optimized mandatory DCI configuration to enhance downlink coverage of Msg4 PDSCH. The UE side pre-configures the repetition count and threshold range, and the UE autonomously determines the number of repetitions for reporting requests. The DCI method completes the UE-specific configuration of the repetition count. This includes the UE autonomously determining the number of repetitions for reporting requests based on channel quality and its corresponding repetition count in pre-configured data.

[0223] In summary, the technical solution proposed in this application can serve as a commercial technical bottleneck for 5G NTN Msg4 PDSCH downlink coverage enhancement; it can achieve Msg4 PDSCH downlink coverage enhancement based on 5G NTN; it can complete cell-level unified configuration through SIB in a hybrid configuration mode, avoiding the large signaling overhead caused by configuring each UE individually; and it can complete specific configuration of a single UE through DCI in a hybrid configuration mode, increasing flexibility and achieving coverage enhancement for UEs with poor beam edge coverage.

[0224] Figure 6 This is a structural diagram of a terminal device according to an embodiment of this application, such as... Figure 6 As shown, the terminal device includes:

[0225] The first acquisition module 62 is used to acquire the channel quality measurement value of the downlink reference signal;

[0226] The first sending module 64 is used to send a request message to the network side via message 3 when the channel quality measurement value is not greater than a first preset threshold. The request message is used to request a new number of repeated transmissions. The new number of repeated transmissions is greater than the preset number of repeated transmissions. Both the new number of repeated transmissions and the preset number of repeated transmissions are the number of times the same message 4 is repeatedly transmitted in the physical downlink shared channel.

[0227] The preset number of repeated transmissions is the default number of repeated transmissions that are pre-set by the terminal device and the network side in a non-broadcast manner. The preset number of repeated transmissions on the terminal device and the preset number of repeated transmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block.

[0228] It should be noted that the above Figure 6 The modules in can be program modules (e.g., a set of program instructions that implements a specific function) or hardware modules. For the latter, they can be represented in the following forms, but are not limited to these: each of the above modules is represented by a processor, or the functions of each of the above modules are implemented by a processor.

[0229] It should be noted that, Figure 6 Preferred embodiments of the shown examples can be found in [reference needed]. Figure 1 The relevant descriptions of the embodiments shown will not be repeated here.

[0230] Figure 7 This is a structural diagram of a terminal device according to an embodiment of this application, such as... Figure 7 As shown, the terminal device includes:

[0231] The second acquisition module 72 is used to acquire the channel quality measurement value of the downlink reference signal;

[0232] The first determining module 74 is used to determine the target preset channel quality measurement threshold interval where the channel quality measurement value is located among multiple preset channel quality measurement threshold intervals;

[0233] The second determining module 76 is used to determine, among multiple preset repeated transmission counts, a target preset repeated transmission count corresponding to a target preset channel quality measurement threshold range, wherein the preset repeated transmission count is the number of times the same message 4 is repeatedly transmitted in the physical downlink shared channel;

[0234] The second sending module 78 is used to send request information to the network side via message 3, wherein the request information includes at least: the target preset number of repeated transmissions.

[0235] It should be noted that the above Figure 7 The modules in can be program modules (e.g., a set of program instructions that implements a specific function) or hardware modules. For the latter, they can be represented in the following forms, but are not limited to these: each of the above modules is represented by a processor, or the functions of each of the above modules are implemented by a processor.

[0236] It should be noted that, Figure 7 Preferred embodiments of the shown examples can be found in [reference needed]. Figure 2 The relevant descriptions of the embodiments shown will not be repeated here.

[0237] This application embodiment also provides a non-volatile storage medium, which includes a stored program, wherein the program, when running, controls the device where the storage medium is located to execute the above-mentioned downlink coverage enhancement and optimization method based on 5G non-terrestrial network.

[0238] The non-volatile storage medium performs the following functions: acquiring the channel quality measurement value of the downlink reference signal; if the channel quality measurement value is not greater than a first preset threshold, sending a request information to the network side through message 3, wherein the request information is used to request a new number of retransmissions; the new number of retransmissions is greater than the preset number of retransmissions; both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel; the preset number of retransmissions is the default number of retransmissions preset by the terminal device and the network side in a non-broadcast manner, and the preset number of retransmissions on the terminal device and the preset number of retransmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block. In addition, the system acquires the channel quality measurement value of the downlink reference signal; determines the target preset channel quality measurement threshold interval where the channel quality measurement value is located among multiple preset channel quality measurement threshold intervals; determines the target preset repeated transmission number corresponding to the target preset channel quality measurement threshold interval among multiple preset repeated transmission numbers, wherein the preset repeated transmission number is the number of times the same message 4 is repeatedly transmitted in the physical downlink shared channel; and sends a request information to the network side through message 3, wherein the request information includes at least the target preset repeated transmission number.

[0239] This application also provides an electronic device, including: a memory and a processor, wherein the processor is used to run a program stored in the memory, wherein the program executes the above-described downlink coverage enhancement and optimization method based on 5G non-terrestrial networks.

[0240] The processor is used to run a program that performs the following functions: acquiring the channel quality measurement value of the downlink reference signal; if the channel quality measurement value is not greater than a first preset threshold, sending a request message to the network side through message 3, wherein the request message is used to request a new number of retransmissions; the new number of retransmissions is greater than the preset number of retransmissions; both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel; the preset number of retransmissions is the default number of retransmissions preset by the terminal device and the network side in a non-broadcast manner, and the preset number of retransmissions on the terminal device and the preset number of retransmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block. In addition, the system acquires the channel quality measurement value of the downlink reference signal; determines the target preset channel quality measurement threshold interval where the channel quality measurement value is located among multiple preset channel quality measurement threshold intervals; determines the target preset repeated transmission number corresponding to the target preset channel quality measurement threshold interval among multiple preset repeated transmission numbers, wherein the preset repeated transmission number is the number of times the same message 4 is repeatedly transmitted in the physical downlink shared channel; and sends a request information to the network side through message 3, wherein the request information includes at least the target preset repeated transmission number.

[0241] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0242] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0243] In the above embodiments of this application, the information collected is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data all comply with relevant laws, regulations and standards, take necessary protective measures, do not violate public order and good morals, and provide corresponding operation entry points for users to choose to authorize or refuse.

[0244] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0245] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0246] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0247] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to related technologies, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0248] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for optimizing downlink coverage enhancement based on a 5G non-terrestrial network, characterized in that, Terminal devices used in 5G non-terrestrial networks include: Obtain channel quality measurements of the downlink reference signal; If the channel quality measurement value is not greater than a first preset threshold, a request message is sent to the network side via message 3, wherein... The request information is used to request a new number of retransmissions; the new number of retransmissions is greater than the preset number of retransmissions; both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel; The preset number of repeated transmissions is the default number of repeated transmissions preset by the terminal device and the network side in a non-broadcast manner. The preset number of repeated transmissions on the terminal device and the preset number of repeated transmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block.

2. The method of claim 1, wherein, After sending the request information to the network side via message 3, the method further includes: Receive the response information sent by the network side in response to the request information, wherein the response information includes at least: a first number of repeated transmissions; The first number of repeated transmissions is determined by the network side based on the resource load index of the network side. The resource load index is used to quantitatively characterize the occupancy of downlink transmission resources. The first number of repeated transmissions determined when the value of the resource load index is greater than the second preset threshold is less than or equal to the first number of repeated transmissions determined when the value of the resource load index is not greater than the second preset threshold.

3. The method according to claim 2, characterized in that, The response information is carried in the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

4. The method according to claim 1, characterized in that, Before obtaining the channel quality measurement value of the downlink reference signal, the method further includes: determining the coverage location type of the terminal device relative to the downlink transmission beam, wherein the coverage location type includes the beam center region and the beam edge region; Acquiring channel quality measurements of the downlink reference signal includes: acquiring the channel quality measurements of the downlink reference signal when the coverage location type is the beam edge region.

5. The method according to claim 4, characterized in that, The method further includes: when the coverage location type is the beam center region, receiving message 4 in the physical downlink shared channel based on the preset number of repeated transmissions.

6. The method according to claim 1, characterized in that, The method further includes: if the channel quality measurement value is greater than the first preset threshold, receiving message 4 in the physical downlink shared channel based on the preset number of repeated transmissions.

7. The method according to claim 1, characterized in that, The request information is carried in at least one of the following: the media access control unit of message 3, the information unit in the radio resource control message carried by the physical uplink shared channel of message 3, and the preset bit field in message 3, wherein the preset bit field includes: one bit.

8. A downlink coverage enhancement and optimization method based on 5G non-terrestrial networks, characterized in that, Terminal devices used in 5G non-terrestrial networks include: Obtain channel quality measurements of the downlink reference signal; Among multiple preset channel quality measurement threshold intervals, the target preset channel quality measurement threshold interval in which the channel quality measurement value is located is determined; Among multiple preset repeated transmission counts, a target preset repeated transmission count corresponding to the target preset channel quality measurement threshold range is determined, wherein the preset repeated transmission count is the number of times the same message 4 is repeatedly transmitted in the physical downlink shared channel; Message 3 sends a request to the network side, wherein the request includes at least the target preset number of repeated transmissions.

9. The method according to claim 8, characterized in that, After sending the request information to the network side via message 3, the method further includes: The network side receives a response message sent in response to the request message, wherein the response message includes at least: a second number of repeated transmissions; The second number of repeated transmissions is determined by the network side based on the resource load index of the network side. The resource load index is used to quantitatively characterize the occupancy of downlink transmission resources. The second number of repeated transmissions determined when the value of the resource load index is greater than a third preset threshold is less than or equal to the second number of repeated transmissions determined when the value of the resource load index is not greater than the third preset threshold.

10. The method according to claim 9, characterized in that, The response information is carried in the reserved bits in the downlink control information of message 4, wherein the reserved bits include: one bit.

11. A terminal device, characterized in that, include: The first acquisition module is used to acquire the channel quality measurement value of the downlink reference signal; The first sending module is configured to send a request message to the network side via message 3 when the channel quality measurement value is not greater than a first preset threshold. The request information is used to request a new number of retransmissions; the new number of retransmissions is greater than the preset number of retransmissions; both the new number of retransmissions and the preset number of retransmissions are the number of times the same message 4 is retransmitted in the physical downlink shared channel; The preset number of repeated transmissions is the default number of repeated transmissions preset by the terminal device and the network side in a non-broadcast manner. The preset number of repeated transmissions on the terminal device and the preset number of repeated transmissions on the network side are configured to the same value, and the configuration does not depend on the broadcast signaling of the system information block.

12. A terminal device, characterized in that, include: The second acquisition module is used to acquire the channel quality measurement value of the downlink reference signal; The first determining module is used to determine the target preset channel quality measurement threshold interval in which the channel quality measurement value is located among multiple preset channel quality measurement threshold intervals; The second determining module is used to determine, among multiple preset repeated transmission counts, a target preset repeated transmission count corresponding to the target preset channel quality measurement threshold range, wherein the preset repeated transmission count is the number of times the same message 4 is repeatedly transmitted in the physical downlink shared channel; The second sending module is used to send request information to the network side via message 3, wherein the request information includes at least: the target preset number of repeated transmissions.

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