Communication method and communication device

Abstract

Provided are a communication method and a communication device, in the method, a first device can send a first message to at least one second device, the first message comprising first indication information, the first indication information being used for indicating a first lead code length and a first data repetition number of subsequent at least one downlink transmission of the first device, therefore, the lead code length of the first device and the second device is aligned with the configuration of the data repetition times, and the large error detection rate caused by blind detection of lead codes with different lengths is avoided.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method and a communication device. Background Art

[0002] The semi-passive Internet of Things (semi-passive IoT) is a low-cost, low-power IoT solution that can achieve wider coverage than passive IoT. However, the downlink of passive or semi-passive IoT can only support low-power receivers with incoherent reception. For example, semi-passive IoT technology supports different coverage levels, and the number of data repetitions and preamble lengths at different coverage levels can be dynamically adjusted. However, in semi-passive IoT technology, the tag side needs to blindly detect preambles of different lengths, that is, use preambles of different lengths to synchronously detect the received signal. This practice will lead to a flat error detection rate, which in turn causes the physical downlink shared channel (PDSCH) data demodulation to fail. Summary of the Invention

[0003] The present application provides a communication method and a communication device, in which a first device can indicate to a second device the first preamble length and the first data repetition number for at least one subsequent downlink transmission, thereby avoiding blind detection of preambles of different lengths resulting in a flat error detection rate.

[0004] In a first aspect, the present application provides a communication method, which is performed by a first device. For example, the first device can be a network device (such as a base station, a reader, etc.), or a component of a network device (such as a processor, a chip, or a chip system, etc.), or a logic module that can realize all or part of the functions of the network device. Among them, the first device determines the first preamble code length and the first data repetition number of at least one subsequent downlink transmission, and sends a first message to at least one second device, the first message including first indication information, and the first indication information is used to indicate the first preamble code length and the first data repetition number of at least one subsequent downlink transmission of the first device.

[0005] In this method, assuming that the first device is a reader and the second device is a tag, and that the at least one subsequent downlink transmission can be the next downlink transmission, or all subsequent downlink transmissions, etc., the first device can indicate the first preamble code length and the first data repetition number of the at least one subsequent downlink transmission to at least one second device through a first message, so that the preamble configuration of the reader and the tag are aligned, avoiding the error detection rate flattening caused by blind detection of preambles of different lengths. The error detection rate flattening means that after the received signal-to-noise ratio reaches a specified value or interval, the error detection rate reaches a stable value, and then as the SNR continues to increase, the error detection rate no longer decreases.

[0006] In one possible implementation, there is a first mapping relationship between the preamble length and the index of the preamble length, and a second mapping relationship between the number of data repetitions and the index of the number of data repetitions. The first indication information includes the index of the first preamble length and the index of the first number of data repetitions.

[0007] In one possible implementation, the first mapping relationship and the second mapping relationship may be the same. For example, the first mapping relationship between the preamble length and the index of the preamble length may also represent the second mapping relationship between the number of data repetitions and the index of the number of data repetitions, that is, the first mapping relationship and the second mapping relationship are the same.

[0008] In the above implementation, it is assumed that there is a preset first mapping relationship between the preamble length and the index of the preamble length, and a preset second mapping relationship between the number of data repetitions and the index of the number of data repetitions, and it is assumed that the above preset first mapping relationship and second mapping relationship are known to both the first device and the second device. The first device can send the index of the first preamble length and the index of the first data repetition number to the second device. After receiving, the second device can determine the first preamble length and the first data repetition number for at least one subsequent downlink transmission based on the first mapping relationship and the second mapping relationship, thereby enabling the first device to indirectly indicate the first preamble length and the first data repetition number for at least one subsequent downlink transmission to the second device, avoiding the blind detection of preambles of different lengths resulting in a flat error detection rate. Optionally, this implementation is conducive to reducing indication overhead.

[0009] In one possible implementation, a third mapping relationship exists between the change in the preamble length of two adjacent downlink transmissions and an index of the change in the preamble length, and a fourth mapping relationship exists between the change in the number of data repetitions and an index of the change in the number of data repetitions. The first indication information includes an index of the change in the first preamble length and an index of the change in the first number of data repetitions. The first preamble length is determined based on the preamble length of the previous downlink transmission and the change in the first preamble length, and the first number of data repetitions is determined based on the number of data repetitions of the previous downlink transmission and the change in the first number of data repetitions.

[0010] In this embodiment, it is assumed that there is a third mapping relationship between the change in the preamble length of two adjacent downlink transmissions and the index of the change in the preamble length, and a fourth mapping relationship between the change in the number of data repetitions and the index of the change in the number of data repetitions, and it is assumed that the above-mentioned preset third mapping relationship and fourth mapping relationship are known to both the first device and the second device. The first device can send the index of the change in the first preamble length and the index of the change in the first data repetition number to the second device. After receiving, the second device can determine the first preamble length and the first data repetition number of the subsequent at least one downlink transmission based on the third mapping relationship and the fourth mapping relationship, as well as the preamble length and the data repetition number of the previous downlink transmission, thereby enabling the first device to indirectly indicate the first preamble length and the first data repetition number of the subsequent at least one downlink transmission to the second device, avoiding the blind detection of preambles of different lengths resulting in a flat error detection rate. Optionally, this embodiment is conducive to further reducing the indication overhead.

[0011] In one possible implementation, the first message further includes second indication information, where the second indication information is used to indicate at least one of a first midamble length or a first postamble length for at least one subsequent downlink transmission by the first device. A fifth mapping relationship exists between the midamble length and the midamble length index, and a sixth mapping relationship exists between the postamble length and the postamble length index, and the second indication information includes at least one of the first midamble length index or the first postamble length index.

[0012] In this embodiment, the first device may further indicate to the second device at least one of the first midamble or the first postamble of at least one subsequent downlink transmission, which is beneficial for aligning the preamble configurations of the first device and the second device, and avoiding blind detection of preambles of different lengths resulting in a flat error detection rate. Optionally, the midamble and / or postamble indication method is similar to the preamble indication method, and can be achieved by indirectly indicating the midamble length index and / or postamble length index, which is beneficial for reducing indication overhead.

[0013] In a possible implementation, there is a seventh mapping relationship between the midamble length and the preamble length, and there is an eighth mapping relationship between the postamble length and the preamble length.

[0014] In this embodiment, it is assumed that there is a seventh mapping relationship between the midamble length and the preamble length, and an eighth mapping relationship between the postamble length and the preamble length, and it is assumed that the above-mentioned preset seventh mapping relationship and eighth mapping relationship are known to both the first device and the second device. Therefore, by indicating the length of the preamble, the first device allows the second device to derive the midamble length based on the length of the preamble and the seventh mapping relationship, and / or derive the postamble length based on the length of the preamble and the eighth mapping relationship. It can be understood that in this embodiment, there is no need to separately send second indication information to indicate at least one of the first midamble length or the first postamble length for at least one subsequent downlink transmission by the first device, which is conducive to further reducing the indication overhead.

[0015] In one possible implementation, when the first device detects uplink data and the detection is successful, the first device uses a first preamble code length and a first data repetition count configuration to send downlink data to a second device, and the second device is the transmitter of the uplink data.

[0016] In this embodiment, if the first device receives uplink data from the second device and detects the uplink data and the detection is successful, it means that the second device has correctly received the first indication information, and the first device and the second device have aligned the preamble configuration. Then, the first device can use the new first preamble code length and the first data repetition number configuration to send downlink data to the second device to realize the data transmission process.

[0017] In one possible implementation, when the first device detects uplink data and fails, the first device uses the configuration of the preamble length and data repetition times of the previous downlink transmission to send downlink data to the second device, which is the transmitter of the uplink data.

[0018] In this embodiment, if the first device does not detect the uplink data from the second device, it means that the second device may not have correctly received the first indication information, and the first device and the second device are not aligned with the preamble configuration. The first device can use the preamble code length and data repetition number configuration of the previous downlink transmission (for example, the default configuration) to send downlink data to the second device to implement the data transmission process.

[0019] In one possible implementation, if the first device fails to detect uplink data after exceeding the first time duration, the first device transmits downlink data to the second device using a second preamble length and a second data repetition count, where the second preamble length is the maximum preamble length in the first mapping relationship, and the second data repetition count is the maximum data repetition count in the second mapping relationship.

[0020] In one possible implementation, the first device exceeding the first time length includes: starting a first timer after the first device sends downlink data, and the first timer timing out (for example, the running time of the first timer exceeds the first time length). Optionally, the condition for terminating the first timer includes: terminating the first timer when the first device successfully receives / detects uplink data.

[0021] In a possible implementation manner, the failure of the first device to detect the uplink data includes: the first device not receiving the uplink data, or the first device receiving the uplink data but failing to decode the data.

[0022] In the above embodiment, when data transmission begins between a first device and a second device, assuming that a first time length (e.g., a maximum time window) is set for each of the first device and the second device, if the first device fails to detect uplink data after exceeding the first time length, indicating that the first device and the second device are not aligned in their preamble configurations, the first device may use a second preamble length and a second data repetition count to transmit downlink data to the second device. The second preamble length and the second data repetition count may be considered default configurations (both being maximum values, corresponding to the maximum time window and the maximum data repetition count).

[0023] In one possible implementation, the first time length is determined based on the maximum time length between two adjacent downlink messages; or, the first time length is determined based on the coverage level of the first device; or, the first time length is determined based on the type of the second device.

[0024] In one possible implementation, a first device sends a second message to at least one second device, where the second message is used to page or select one or more second devices; the first device sends a third message to at least one second device, where the third message is used to indicate the number of random access opportunities; and the first device sends a fourth message to at least one second device, where the fourth message is used to indicate the random access opportunities. The second, third, and fourth messages all use a second preamble length and a second data repetition count; the second preamble length is the maximum preamble length in the first mapping relationship, and the second data repetition count is the maximum data repetition count in the second mapping relationship.

[0025] In this embodiment, before the first device sends the first message to at least one second device, it can also send a second message, a third message and a fourth message to the at least one second device, and the second message, the third message and the fourth message all use the second preamble code length and the second data repetition number configuration, which is beneficial for the first device and the second device to have unaligned preamble configurations, and avoid blind detection of preambbles of different lengths resulting in a flat error detection rate.

[0026] In a possible implementation, a first device receives a random access request message from at least one second device, where the random access request message indicates that contention resolution for the at least one second device is successful; and the first message also includes the random access request message.

[0027] In a possible implementation manner, the random access request message includes at least one of a random number, a terminal identifier, a terminal temporary identifier, a contention resolution identifier, and a random access identifier.

[0028] In the above-described embodiment, the first device can receive a random access request message, thereby determining that the contention with the second device has been successfully resolved; and can send a first message to the second device, thereby indicating to the second device the first preamble length and the first data repetition count for at least one subsequent downlink transmission, so that the reader and the tag preamble configuration are aligned, thereby avoiding blind detection of preambles of different lengths resulting in a flat error detection rate. Optionally, the first message can be a broadcast message, and the first message includes a random access request message, which can enable the corresponding second device to determine that it can adopt the preamble configuration indicated in the first message.

[0029] On the second aspect, the present application provides a communication method, which is performed by a second device. For example, the second device can be a terminal (such as a tag, etc.), or a terminal or a communication module in the terminal, or a circuit or chip in the terminal responsible for the communication function (such as a modem chip, also known as a baseband chip, or a system on chip (SoC) chip or system in package (SIP) chip containing a modem core). The second device receives a first message from the first device, and the first message includes a first indication information, and the first indication information is used to indicate the first preamble code length and the first data repetition number of subsequent downlink transmissions of the first device. The second device applies the configuration of the first preamble code length and the first data repetition number.

[0030] In this method, it is assumed that the first device is a reader and the second device is a tag. The subsequent at least one downlink transmission can be the next downlink transmission, or all subsequent downlink transmissions, etc. The second device receives the first message and can determine the first preamble code length and the first data repetition number of the subsequent at least one downlink transmission, so that the preamble configuration of the reader and the tag are aligned, avoiding the flattening of the error detection rate caused by blind detection of preambles of different lengths.

[0031] In one possible implementation, there is a first mapping relationship between the preamble length and the index of the preamble length, and a second mapping relationship between the number of data repetitions and the index of the number of data repetitions. The first indication information includes the index of the first preamble length and the index of the first number of data repetitions.

[0032] In one possible implementation, the first mapping relationship and the second mapping relationship may be the same. For example, the first mapping relationship between the preamble length and the index of the preamble length may also represent the second mapping relationship between the number of data repetitions and the index of the number of data repetitions, that is, the first mapping relationship and the second mapping relationship are the same.

[0033] In the above implementation, it is assumed that there is a preset first mapping relationship between the preamble length and the index of the preamble length, and a preset second mapping relationship between the number of data repetitions and the index of the number of data repetitions, and it is assumed that the above preset first mapping relationship and second mapping relationship are known to both the first device and the second device. The first device can send the index of the first preamble length and the index of the first data repetition number to the second device. After receiving, the second device can determine the first preamble length and the first data repetition number for at least one subsequent downlink transmission based on the first mapping relationship and the second mapping relationship, thereby enabling the first device to indirectly indicate the first preamble length and the first data repetition number for at least one subsequent downlink transmission to the second device, avoiding the blind detection of preambles of different lengths resulting in a flat error detection rate. Optionally, this implementation is conducive to reducing indication overhead.

[0034] In one possible implementation, a third mapping relationship exists between the change in the preamble length of two adjacent downlink transmissions and an index of the change in the preamble length, and a fourth mapping relationship exists between the change in the number of data repetitions and an index of the change in the number of data repetitions. The first indication information includes an index of the change in the first preamble length and an index of the change in the first number of data repetitions. The first preamble length is determined based on the preamble length of the previous downlink transmission and the change in the first preamble length, and the first number of data repetitions is determined based on the number of data repetitions of the previous downlink transmission and the change in the first number of data repetitions.

[0035] In this embodiment, it is assumed that there is a third mapping relationship between the change in the preamble length of two adjacent downlink transmissions and the index of the change in the preamble length, and a fourth mapping relationship between the change in the number of data repetitions and the index of the change in the number of data repetitions, and it is assumed that the above-mentioned preset third mapping relationship and fourth mapping relationship are known to both the first device and the second device. The first device can send the index of the change in the first preamble length and the index of the change in the first data repetition number to the second device. After receiving, the second device can determine the first preamble length and the first data repetition number of the subsequent at least one downlink transmission based on the third mapping relationship and the fourth mapping relationship, as well as the preamble length and the data repetition number of the previous downlink transmission, thereby enabling the first device to indirectly indicate the first preamble length and the first data repetition number of the subsequent at least one downlink transmission to the second device, avoiding the blind detection of preambles of different lengths resulting in a flat error detection rate. Optionally, this embodiment is conducive to further reducing the indication overhead.

[0036] In one possible implementation, the first message further includes second indication information, where the second indication information is used to indicate at least one of a first midamble length or a first postamble length for at least one subsequent downlink transmission by the first device. A fifth mapping relationship exists between the midamble length and the midamble length index, and a sixth mapping relationship exists between the postamble length and the postamble length index, and the second indication information includes at least one of the first midamble length index or the first postamble length index.

[0037] In this embodiment, the first device may also indicate to the second device at least one of the first midamble or the first postamble of at least one subsequent downlink transmission, which is beneficial for aligning the preamble configurations of the first device and the second device, and avoiding blind detection of preambles of different lengths resulting in a flat error detection rate. Optionally, the indication method of the midamble and / or postamble is similar to that of the preamble, and can be achieved by indirectly indicating the midamble length index and / or the postamble length index, which is beneficial for reducing indication overhead.

[0038] In a possible implementation, there is a seventh mapping relationship between the midamble length and the preamble length, and there is an eighth mapping relationship between the postamble length and the preamble length.

[0039] In this embodiment, it is assumed that there is a seventh mapping relationship between the midamble length and the preamble length, and an eighth mapping relationship between the postamble length and the preamble length, and it is assumed that the above-mentioned preset seventh mapping relationship and eighth mapping relationship are known to both the first device and the second device. Therefore, by indicating the length of the preamble, the first device allows the second device to derive the midamble length based on the length of the preamble and the seventh mapping relationship, and / or derive the postamble length based on the length of the preamble and the eighth mapping relationship. It can be understood that in this embodiment, there is no need to separately send second indication information to indicate at least one of the first midamble length or the first postamble length for at least one subsequent downlink transmission by the first device, which is conducive to further reducing the indication overhead.

[0040] In one possible implementation, the second device sends uplink data to the first device. When the first device detects the uplink data and the detection is successful, the second device receives downlink data from the first device, where the downlink data is generated by the first device using the first preamble length and the first data repetition count.

[0041] In this embodiment, after the second device successfully receives the first message, it can adopt the new configuration of the first preamble length and the first data repetition count, that is, align the preamble configurations of the first and second devices. In addition, the second device can send uplink data to the first device, completing the data transmission process.

[0042] In one possible implementation, the second device sends uplink data to the first device. When the first device detects the uplink data and fails, the second device receives downlink data from the first device, where the downlink data is generated by the first device using the preamble length and data repetition count configured in a previous downlink transmission.

[0043] In this implementation, when the second device sends uplink data to the first device, but the first device fails to detect the uplink data, there may be a situation where the preamble configurations of the first device and the second device are not aligned, so the second device receives the downlink data again to implement the data transmission process.

[0044] In one possible implementation, a second device receives a second message for paging or selecting one or more second devices; the second device receives a third message for indicating the number of random access opportunities; and the second device receives a fourth message for indicating the number of random access opportunities. The second, third, and fourth messages all employ a second preamble length and a second data repetition count; the second preamble length is the maximum preamble length in the first mapping relationship, and the second data repetition count is the maximum data repetition count in the second mapping relationship.

[0045] In this embodiment, the second device can receive the second, third, and fourth messages before receiving the first message, thereby implementing a random access process. Furthermore, the second, third, and fourth messages all use the second preamble length and the second data repetition count, which facilitates misaligned preamble configurations between the first and second devices and avoids blind detection of preambles of different lengths that can lead to a flat error detection rate.

[0046] In one possible implementation, the second device determines a first initial value based on the number of random access opportunities; the first initial value is updated based on the number of times the second device receives the fourth message. When the first initial value satisfies the first value, the second device sends a random access request message to the first device, indicating that contention resolution was successful for the second device.

[0047] In this embodiment, the second device may set a first initial value (e.g., configure a first timer counter), which is related to the number of times the fourth message is sent and the number of random access opportunities indicated by the third message. When the second device successfully resolves the contention, the second device may send a random access request message to the first device, thereby indicating to the first device that the contention resolution for the second device is successful. Optionally, the random access request message includes a random sequence.

[0048] In a third aspect, the present application provides a communication device. The communication device may be a network device, or a component of a network device (such as a processor, a chip, or a chip system, etc.), or a device that can be used in conjunction with a network device. In one possible implementation, the communication device has the function of implementing the second aspect above. For example, the communication device includes a module or unit or means corresponding to the operation involved in the second aspect above. The module or unit or means can be implemented specifically through software, or through hardware, or through a combination of software and hardware.

[0049] In one possible implementation, the communication device includes a communication unit and a processing unit. The processing unit is configured to determine a first preamble length and a first data repetition count for at least one subsequent downlink transmission, and the communication unit is configured to send a first message to at least one second device, the first message including first indication information, the first indication information being configured to indicate a first preamble length and a first data repetition count for at least one subsequent downlink transmission by the first device.

[0050] In this embodiment, the first device can indicate the first preamble code length and the first data repetition number of at least one subsequent downlink transmission to at least one second device through a first message, so that the preamble configuration of the first device is aligned with that of the second device, avoiding the flattening of the error detection rate caused by blind detection of preambbles of different lengths.

[0051] Optionally, other possible implementations in the third aspect can refer to the corresponding descriptions of other possible implementations in the first aspect, and will not be repeated here.

[0052] In a fourth aspect, the present application provides a communication device. The communication device may be a terminal, or a component of a terminal (such as a processor, a chip, or a chip system, etc.), or a device that can be used in conjunction with a terminal. In one possible implementation, the communication device has the function of implementing the first aspect above. For example, the communication device includes a module or unit or means corresponding to the operation involved in the first aspect above. The module or unit or means can be implemented by software, or by hardware, or by a combination of software and hardware.

[0053] In one possible implementation, the communication device includes a communication unit and a processing unit. The communication unit receives a first message from a first device, the first message including first indication information, the first indication information being used to indicate a first preamble length and a first data repetition count for at least one subsequent downlink transmission by the first device. The processing unit is configured to apply the configuration of the first preamble length and the first data repetition count.

[0054] In this embodiment, the second device receives the first message and can determine the first preamble code length and the first data repetition number of at least one subsequent downlink transmission, so that the preamble configuration of the second device is aligned with that of the first device, avoiding blind detection of preambles of different lengths resulting in a flat error detection rate.

[0055] Optionally, other possible implementations of the fourth aspect can refer to the corresponding descriptions of other possible implementations of the second aspect, and will not be repeated here.

[0056] In a fifth aspect, the present application provides a communication device comprising a memory and one or more processors. The memory is used to store part or all of the necessary computer programs or instructions for implementing the functions involved in at least one of the first and second aspects above. The one or more processors can execute the computer programs or instructions. When the computer programs or instructions are executed, the communication device implements at least one of the following: the method in the first aspect and any possible implementation of the first aspect, and the method in the second aspect and any possible implementation of the second aspect.

[0057] In one possible design, the communication device may further include an interface circuit, wherein the processor is configured to communicate with other devices or components through the interface circuit.

[0058] In one possible design, the communication device may further include a memory.

[0059] In one possible design, the communication device may be a terminal, or a communication module in a terminal, or a chip in the terminal responsible for communication functions such as a modem chip or a SoC or SIP chip including a modem module.

[0060] In a sixth aspect, the present application provides a communication device comprising: a processor and an interface circuit, the interface circuit being used to receive signals from other communication devices and transmit them to the processor or to send signals from the processor to other communication devices, the processor being used to implement at least one of the following through logic circuits or execution code instructions: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0061] In the seventh aspect, the present application provides a communication system, which includes at least one device or equipment among the third to sixth aspects above, so that the at least one device or equipment above performs at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0062] In an eighth aspect, the present application provides a computer-readable storage medium storing instructions, which, when executed on a computer, causes the computer to execute at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0063] In a ninth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, cause the computer to execute at least one of the following: the method of the first aspect and any possible implementation of the first aspect, the method of the second aspect and any possible implementation of the second aspect.

[0064] In a tenth aspect, the present application provides a chip comprising a processor (or a logic circuit). Optionally, the chip may further comprise a communication interface (or interface) for implementing at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect. In one possible implementation, if the chip is the smallest processing unit in the entire machine, the chip may be a processor, or may comprise a processor and a memory, or may comprise a processor, a memory, and a transceiver, for implementing at least one of the following: the method in the first aspect and any possible implementation of the first aspect, the method in the second aspect and any possible implementation of the second aspect.

[0065] In an eleventh aspect, the present application provides a chip system. The chip system includes a processor and an interface. Optionally, the chip system may also include a memory for implementing at least one of the following: the method in the first aspect and any possible implementation of the first aspect, and the method in the second aspect and any possible implementation of the second aspect. The chip system may be composed of a chip or may include a chip and other discrete components. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 A schematic diagram of a communication system provided in this application;

[0067] Figure 2 A flow chart of a communication method provided in this application;

[0068] Figure 3 A flowchart of another communication method provided by this application;

[0069] Figure 4 A schematic diagram of a communication device provided in this application;

[0070] Figure 5 A schematic diagram of another communication device provided in this application. DETAILED DESCRIPTION

[0071] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0072] 1. For ease of understanding, the following is a detailed introduction to the definitions of relevant terms involved in this application:

[0073] 1. Network architecture:

[0074] The communication method provided in this application can be applied to Figure 1 In the communication system shown in FIG. , for example, the communication system includes a reader and a tag, and the reader and the tag can communicate with each other.

[0075] In this application, a reader / writer can be a device in a wireless communication system, such as an access network device or a terminal device. A tag can be a radio frequency identification technology (RFID) tag, a tag with similar functionality, or a terminal device in a wireless communication system.

[0076] In this application, the first device may be the reader / writer described above, and the second device may be the tag described above. For example, the first device may be a network device in a wireless communication system, and the second device may be a terminal device equipped with an RFID. The network device may initiate access or positioning procedures to the terminal device, and the terminal device may cooperate with the network device to complete the corresponding procedures.

[0077] Among them, access network equipment is a device with wireless transceiver functions used to communicate with terminal devices. For example, an access network device is a radio access network (RAN) node that connects terminal devices to a wireless network. RAN nodes include, but are not limited to: gNB, transmission reception point (TRP), evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), base band unit (BBU), wireless fidelity (Wifi) access point (AP), integrated access and backhaul (IAB), etc.

[0078] Access network devices can communicate and interact with core network devices to provide communication services to terminal devices. Core network devices are, for example, devices in the 5G core network (CN). As a bearer network, the core network provides an interface to the data network, providing communication connections, authentication, management, policy control, and data service delivery for terminals.

[0079] A terminal is a device with wireless transceiver capabilities that can send signals to a base station or receive signals from a base station. A terminal can also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, wearable device, vehicle, airplane, ship, robot, robotic arm, smart home device, etc. The embodiments of this application do not limit the specific technology and specific device form adopted by the terminal.

[0080] Base stations and terminals can be fixed or mobile. They can be deployed on land, indoors or outdoors, handheld or vehicle-mounted; on water; or on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of base stations and terminals.

[0081] In this application, the functions of the base station can also be performed by a module in the base station (such as a chip), or by a control subsystem that includes the base station function. The control subsystem that includes the base station function here can be the control center in the above-mentioned application scenarios such as smart grid, industrial control, smart transportation, and smart city. The functions of the terminal can also be performed by a module in the terminal (such as a chip or modem), or by a device that includes the terminal function.

[0082] In this application, a base station sends downlink signals or downlink information to a terminal, and the downlink information is carried on a downlink channel; the terminal sends uplink signals or uplink information to the base station, and the uplink information is carried on an uplink channel. In order to communicate with the base station, the terminal needs to establish a wireless connection in the cell controlled by the base station. The cell with which the terminal has established a wireless connection is called the serving cell of the terminal. When the terminal communicates with the serving cell, it will also be interfered with by signals from neighboring cells.

[0083] 2. Semi-passive Internet of things (semi-passive IoT) technology:

[0084] Semi-passive IoT technology is a low-cost, low-power IoT solution that can achieve wider coverage than passive IoT. However, the downlink of semi-passive IoT can only support low-power receivers with non-coherent reception. For example, the downlink of semi-passive IoT uses non-coherent reception methods such as envelope detection. Due to power consumption and cost constraints, the modulation method is usually on-off keying (OOK) modulation. OOK modulation represents high and low voltage levels by sending (represented by "1") and not sending (represented by "0") signals. For example, within a level time, if the signal amplitude is 0, it means that the signal is not being sent, and 0 is transmitted; if the signal amplitude is not 0, it means that the signal is being sent, and 1 is transmitted.

[0085] When transmitting downlink data, the base station adds a preamble in front of the data signal and a postamble after the data. The tag determines the location of the data by detecting the preamble and postamble. For example, one possible detection method is that the tag receives the signal within the time window where the preamble / postamble may arrive (based on envelope detection) and generates a local preamble signal. The local preamble signal is sliding correlated with the received signal. The position with the largest correlation value is the timing position of the preamble / postamble. Assume that the signal after OOK demodulation is r i , r i ∈{0,1}, the tag can convert both the received signal and the local signal into a binary phase signal (such as yi=1-2*r i ) and then perform correlation.

[0086] Optionally, due to the existence of sampling frequency offset (SFO), even if the reader and tag are accurately time-synchronized through the preamble, there will be time deviation in the subsequent sampling of the data signal. Especially when the data frame length is large, the cumulative error caused by SFO will also become larger. Therefore, it is necessary to periodically insert the mid-amble to correct the time deviation in a timely manner.

[0087] Optionally, semi-passive IoT technology supports different coverage levels, and the number of data repetitions and preamble lengths can be dynamically adjusted at different coverage levels. Different preamble lengths can implicitly indicate the number of data repetitions. Currently, tags cannot know the specific length of the preamble and need to blindly detect preambles of different lengths. However, blindly detecting preambles of different lengths will result in a high false detection rate, which in turn causes failures in physical downlink shared channel (PDSCH) data demodulation. For example, suppose the preamble set contains 8-length and 16-length sequences, represented as [0,0,1,0,1,0,0,0] and [0,0,1,0,1,0,0,0,1,1,0,1,0,1,1,1]. Assuming that the transmitter actually sends an 8-length sequence, the receiver uses both the 8-length and 16-length sequences to synchronize with the received sequence. If the maximum peak is the maximum correlation value obtained by synchronizing with the 16-length sequence, then a false detection has occurred. The error detection rate will gradually decrease until it reaches a plateau and remains at 14%. False detection of the preamble will cause the receiver to misjudge the number of PDSCH data repetitions, resulting in data demodulation failure.

[0088] Therefore, in order to avoid a large false detection rate caused by blind detection of preambles of different lengths, the present application provides a communication method, which is suitable for semi-passive IoT scenarios. The reader can indicate the preamble length and number of data repetitions for the next downlink transmission to the tag based on signaling, thereby avoiding false detection or missed detection and ensuring the correct transmission of data.

[0089] 2. Communication method provided by this application:

[0090] 1. For example, Figure 2 This is a flow chart of a communication method provided by this application. The method can be implemented by interaction between a first device and a second device, the first device being, for example, a base station or a base station device, and the second device being, for example, a terminal or a terminal device. Optionally, Figure 2 Only one second device is shown. The first device can interact with multiple second devices. The specific interaction process is the same as Figure 2 The interaction process of the second device in is similar. The method includes the following steps:

[0091] S101, a first device determines a first preamble length and a first data repetition number for at least one subsequent downlink transmission.

[0092] In one possible implementation, at least one subsequent downlink transmission may refer to the next downlink transmission, for example, the first device determines the first preamble code length and the first data repetition number of the next downlink transmission; or, at least one subsequent downlink transmission may include all subsequent downlink transmissions, for example, the first device determines that all subsequent downlink transmissions use the first preamble code length and the first data repetition number.

[0093] In one possible implementation, the first preamble length may be any one of candidate preamble lengths, and the first data repetition count may be any one of candidate data repetition counts. For example, candidate preamble lengths may include, but are not limited to, 8, 16, 32, 64, and the like, and candidate data repetition counts may include, but are not limited to, 1, 2, 4, 8, 16, and the like. The first apparatus may determine the first preamble length and / or the first data repetition count from the candidate preamble lengths and / or candidate data repetition counts.

[0094] S102: A first device sends a first message to at least one second device, and correspondingly, the second device receives the first message.

[0095] The first message includes first indication information, and the first indication information is used to indicate the first preamble length and the first data repetition number for at least one subsequent downlink transmission by the first device. In other words, the first device can carry the first indication information in the first message to indicate the first preamble length and the first data repetition number for at least one subsequent downlink transmission to the second device.

[0096] In a possible implementation, the first device may adopt an explicit indication method, for example, the first indication information occupies one or more bits, and the one or more bits carry the first preamble code length and the first data repetition number.

[0097] In a possible implementation, the first device may adopt an implicit indication method, which may specifically include but is not limited to the following situations:

[0098] Case 1: The first indication information occupies one or more bits, and the one or more bits carry an index of the first preamble code length and an index of the first data repetition number.

[0099] In scenario 1, it is assumed that a first mapping relationship exists between the preamble length and the index of the preamble length, and a second mapping relationship exists between the number of data repetitions and the index of the number of data repetitions. Furthermore, it is assumed that both the first device and the second device are preconfigured with the first mapping relationship and the second mapping relationship. For example, Table 1 is a table of the first mapping relationship, and Table 2 is a table of the second mapping relationship.

[0100] Table 1: First mapping relationship

[0101] Index of preamble length Preamble length 0 8 1 16 2 32 3 64 4 128 … …

[0102] Table 2: Second mapping relationship

[0103] Index of the number of times data is repeated Number of data repetitions 0 1 1 2 2 4 3 8 4 16 … …

[0104] For example, assuming that the first indication information uses at least 3 bits to carry the index of the preamble length and at least 3 bits to carry the index of the number of data repetitions, the first indication information in the examples of Tables 1 and 2 above requires a total of at least 6 bits to indicate the index of the first preamble length and the index of the first number of data repetitions. Correspondingly, the second device receives the index of the first preamble length and the index of the first number of data repetitions, and can determine the first preamble length and the first number of data repetitions by combining the first mapping relationship shown in Table 1 and the second mapping relationship shown in Table 2. Optionally, the indication method of case 1 can reduce the indication overhead compared to the indication method that directly carries the first preamble length and the first number of data repetitions. Optionally, Tables 1 and 2 above are only examples, and this application does not limit the specific implementation of the first mapping relationship and the second mapping relationship. For example, the first mapping relationship can also be a first functional relationship between the index of the preamble length and the preamble length, and the second mapping relationship can also be a second functional relationship between the index of the number of data repetitions and the number of data repetitions, etc., which are not limited here.

[0105] Case 2: The first indication information occupies one or more bits, and the one or more bits carry an index of a change in the length of the first preamble code and an index of a change in the number of repetitions of the first data.

[0106] In scenario 2, to further reduce signaling indication overhead, considering that the second device has a relatively low mobility and the coverage level changes slightly between two adjacent downlinks, the first device may use a differential indication method. For example, the first device may indicate the change in preamble length and / or data repetition count through first indication information, thereby indicating the first preamble length and first data repetition count to the second device.

[0107] In one possible implementation, it is assumed that the first indication information includes the change in the first preamble length and the change in the first data repetition number, that is, the first device directly indicates the change in the first preamble length and the change in the first data repetition number to the second device. Correspondingly, the second device receives the first indication information and can determine the first preamble length based on the preamble length of the previous downlink transmission and the change in the first preamble length (for example, the first preamble length can be obtained by adding the change in the preamble length of the previous downlink transmission and the first preamble length); similarly, the second device can determine the first data repetition number based on the data repetition number of the previous downlink transmission and the change in the first data repetition number.

[0108] In one possible implementation, it is assumed that a third mapping relationship exists between the change in preamble length between two adjacent downlink transmissions and the index of the change in preamble length, and a fourth mapping relationship exists between the change in the number of data repetitions and the index of the change in the number of data repetitions, and it is assumed that both the first device and the second device are preconfigured with the third and fourth mapping relationships. For example, Table 3 is a table of the third mapping relationship, and Table 4 is a table of the fourth mapping relationship.

[0109] Table 3: The third mapping relationship

[0110] Index of the change in preamble length Change in preamble length 0 +Δ 1 -Δ 2 0

[0111] Table 4: Fourth mapping relationship

[0112] Index of the change in the number of data repetitions Change in the number of data repetitions 0 +α 1 -α 2 0

[0113] For example, assuming that the first indication information uses 2 bits to carry the index of the change in the length of the preamble code and 2 bits to carry the index of the change in the number of data repetitions, the first indication information in the examples of Table 3 and Table 4 above requires a total of 4 bits to indicate the index of the change in the length of the first preamble code and the index of the change in the number of first data repetitions. Correspondingly, the second device receives the index of the change in the length of the first preamble code and the index of the change in the number of first data repetitions, and combines the third mapping relationship shown in Table 3 and the fourth mapping relationship shown in Table 4 to determine the change in the length of the first preamble code and the change in the number of first data repetitions, thereby determining the first preamble code length and the first data repetitions. It can be understood that the indication method of case 2 can further reduce the indication overhead compared to the indication method of case 1.

[0114] In one possible implementation, the value of Δ is 1 or -1. Taking Δ=1 as an example, if the index of the preamble length used in the current downlink transmission is 2, and the index bit value of the change in the preamble length is 0, then the preamble length used in the next downlink transmission is 64. Similarly, the value of α is 1 or -1. Taking α=1 as an example, if the index of the number of data repetitions used in the current downlink transmission is 1, and the index bit value of the change in the number of data repetitions is 0, then the number of data repetitions used in the next downlink transmission is 3. It should be noted that the value of α is a positive integer.

[0115] Optionally, based on the above-mentioned third mapping relationship or fourth mapping relationship, the first device can also configure the first indication information as: using 1 bit to indicate whether the preamble code length changes (for example, the value of this 1 bit is 0 to indicate that the preamble code length has not changed, and the value is 1 to indicate that the preamble code length has changed, and vice versa), and using another 1 bit to indicate the change amount of the preamble code length (if the preamble code length has not changed, the value of this 1 bit is 0, otherwise it indicates the change amount, and vice versa); similarly, using 1 bit to indicate whether the number of data repetitions changes, and using another 1 bit to indicate the change amount of the data repetitions.

[0116] Optionally, the above Tables 3 and 4 are only examples, and the present application does not limit the specific implementation methods of the third mapping relationship and the fourth mapping relationship. For example, the third mapping relationship can also be a first functional relationship between the index of the change in the length of the preamble code and the change in the length of the preamble code, and the fourth mapping relationship can also be a fourth functional relationship between the index of the change in the number of data repetitions and the change in the number of data repetitions, etc., which is not limited here.

[0117] Optionally, the first message also includes second indication information, and the second indication information is used to indicate at least one of the first midamble length or the first post-amble length of at least one subsequent downlink transmission of the first device. That is, the first device can carry the second indication information in the first message, thereby indicating to the second device the first midamble length and / or the first post-amble length of at least one subsequent downlink transmission. The midamble is used to correct timing errors in a timely manner. For example, due to sampling frequency deviation errors, synchronization errors may still exist after preamble synchronization, and timing errors will continue to accumulate over time and need to be corrected in a timely manner. Otherwise, the synchronization position of the post-amble will differ greatly from the actual position, and the window required for sliding detection will be larger, resulting in performance degradation and increased detection complexity of the post-amble. The post-amble is used as an end identifier for downlink data.

[0118] In a possible implementation, the first device may adopt an explicit indication method, for example, the second indication information occupies one or more bits, and the one or more bits carry the first midamble length and / or the first postamble length.

[0119] In a possible implementation, the first device may adopt an implicit indication method, which may specifically include but is not limited to the following situations:

[0120] Case 1: the second indication information occupies one or more bits, and the one or more bits carry at least one of the index of the first midamble length or the index of the first postamble length.

[0121] In scenario 1, it is assumed that a fifth mapping relationship exists between midamble lengths and midamble length indices, and a sixth mapping relationship exists between postamble lengths and postamble length indices, and it is assumed that both the first device and the second device are preconfigured with the fifth and sixth mapping relationships. For example, Table 5 is a table of the fifth mapping relationship, and Table 6 is a table of the sixth mapping relationship.

[0122] Table 5: Fifth mapping relationship

[0123] Index of midamble length Midamble length 0 8 1 16 2 32 3 64 4 128 … …

[0124] Table 6: Sixth mapping relationship

[0125] Index of post-amble length Post-amble length 0 8 1 16 2 32 3 64 4 128 … …

[0126] For example, assuming that the second indication information uses at least 3 bits to carry the index of the midamble length and at least 3 bits to carry the index of the postamble length, the second indication information in the examples of Tables 5 and 6 above requires a total of at least 6 bits to indicate the index of the first midamble length and the index of the first postamble length. Correspondingly, the second device receives the index of the first midamble length and the index of the first postamble length, and combines the fifth mapping relationship shown in Table 5 and the sixth mapping relationship shown in Table 6 to determine the index of the first midamble length and the index of the first postamble length. Optionally, using the indication method of case 1 can reduce the indication overhead compared to the indication method of directly carrying the first midamble length and the first postamble length. Optionally, Tables 5 and 6 above are only examples, and this application does not limit the specific implementation of the fifth mapping relationship and the sixth mapping relationship. For example, the fifth mapping relationship can also be a fifth functional relationship between the index of the midamble length and the midamble length, and the sixth mapping relationship can also be a sixth functional relationship between the index of the postamble length and the postamble length, etc., which are not limited here.

[0127] Case 2: The first message does not include the second indication information. The first device can indirectly indicate at least one of the indexes of the first midamble length or the first postamble length through the first indication information and the relationship between the midamble length, postamble length and preamble length.

[0128] In scenario 2, it is assumed that a seventh mapping relationship exists between the midamble length and the preamble length, and an eighth mapping relationship exists between the postamble length and the preamble length. Furthermore, it is assumed that both the first device and the second device are preconfigured with the seventh and eighth mapping relationships. For example, Table 7 is a table for the seventh mapping relationship, and Table 8 is a table for the eighth mapping relationship.

[0129] Table 7: Seventh mapping relationship

[0130]

[0131]

[0132] Table 8: Eighth mapping relationship

[0133] Post-amble length Preamble length 8 8 16 16 32 32 64 64 128 128 … …

[0134] For example, assuming that the first indication information indicates the first preamble length, the second device can determine the first midamble length based on the first preamble length and the seventh mapping relationship; and can determine the first postamble length based on the first preamble length and the eighth mapping relationship. It can be understood that in case two, there is no need to send the second indication information, which helps reduce indication overhead. Optionally, Tables 7 and 8 above are merely examples, and this application does not limit the specific implementation of the seventh and eighth mapping relationships. For example, the seventh mapping relationship can also be a seventh functional relationship between the preamble length and the midamble length, and the eighth mapping relationship can also be an eighth functional relationship between the preamble length and the postamble length, etc., which are not limited here. Optionally, the examples in Tables 7 and 8 above assume that the midamble length and the preamble length are the same, but the midamble length and the preamble length can also be different. For example, assuming that the midamble length is 8, the corresponding preamble length is 16; and the midamble length is 16, the corresponding preamble length is 8, which is not limited in this application. Optionally, the examples in Tables 7 and 8 above assume that the length of the post-amble is the same as the length of the preamble, but the length of the post-amble and the length of the preamble may also be different. For example, assuming that the length of the post-amble is 8, the length of the corresponding preamble is 24; the length of the post-amble is 24, and the length of the corresponding preamble is 8. This application does not limit this.

[0135] Optionally, the first indication information may be a high-layer indication or a physical layer indication. For example, the first message may be a radio resource control (RRC) message or a media access control-element (MAC (media access control) control element, MAC CE) message, etc., which is not limited in this application.

[0136] Optionally, the second device may determine a preamble configuration for at least one subsequent downlink transmission based on the first indication information, and the physical layer may use the preamble configuration to detect at least one subsequent downlink message.

[0137] In this embodiment, the first device can indicate the first preamble code length and the first data repetition number of at least one subsequent downlink transmission to at least one second device through the first message, so that the preamble configuration of the first device is aligned with that of the second device, avoiding blind detection of preambbles of different lengths resulting in a higher false detection rate.

[0138] 2. For example, Figure 3 This is a flow chart of another communication method provided by this application. This method can be implemented by interaction between a first device and a second device, where the first device is, for example, a reader and the second device is, for example, a tag. Optionally, Figure 3 Only one second device is shown. The first device can interact with multiple second devices. The specific interaction process is the same as Figure 3 The interaction process of the second device in is similar. The method includes the following steps:

[0139] S201, a first device sends a second message to at least one second device; correspondingly, the second device receives the second message.

[0140] The second message is used to page or select one or more second devices. For example, the second message may be a select / paging message used to select one or more tags.

[0141] In one possible implementation, the second message may carry multiple parameters, such as an inventory session, an action, and a mask (e.g., a mask). Accordingly, one or more second devices receive the second message. If the group identifier of the second device matches the group identifier in the second message, the second device may configure a flag based on the parameters in the second message.

[0142] In one possible implementation, the second message uses a configuration of a second preamble length and a second data repetition count. For example, the second preamble length is the maximum preamble length in the first mapping relationship, and the second data repetition count is the maximum data repetition count in the second mapping relationship. Optionally, the configuration of the second preamble length and the second data repetition count can also be referred to as a default configuration, thereby preventing the tag from participating in a new inventory process due to misalignment of the reader and tag preamble configurations.

[0143] S202, the first device sends a third message to at least one second device; correspondingly, the second device receives the third message.

[0144] The third message is used to indicate the number of random access opportunities. For example, the third message may be a query message that carries parameters such as a Q value, a session, and a flag. The Q value identifies the number of random access opportunities.

[0145] In one possible implementation, the third message uses the second preamble length and the second data repetition number to avoid the tag being unable to participate in a new round of inventory process due to misalignment of the preamble configurations of the reader and the tag.

[0146] S203: The second device determines a first initial value based on the number of random access opportunities.

[0147] For example, when the session and flag of the second device match the session and flag in the third message, the second device can randomly generate a 0-2 Q-1 A random number is used as the first initial value. Optionally, the first initial value can be regarded as the initial value of a counter.

[0148] Optionally, if the second device does not send a random access request message to the first device, continue to execute S204; if the second device sends a random access request message to the first device, continue to execute S205.

[0149] In a possible implementation manner, the random access request message includes at least one of a random number, a terminal identifier, a terminal temporary identifier, a contention resolution identifier, and a random access identifier.

[0150] S204, the first device sends a fourth message to at least one second device; correspondingly, the second device receives the fourth message.

[0151] The fourth message is used to indicate a random access opportunity. For example, the fourth message may be a command (QueryRep) message for sending a start of a next time slot.

[0152] In a possible implementation, the fourth message adopts the configuration of the second preamble length and the second data repetition number, thereby avoiding the tag being unable to participate in a new round of inventory process due to the misalignment of the preamble configurations of the reader and the tag.

[0153] In one possible implementation, the first initial value is updated based on the number of times the second device receives the fourth message; for example, each time the second device receives a QueryRep, the first initial value is updated (for example, the counter is incremented or decremented).

[0154] Optionally, the first device may send one or more of the second message, the third message, or the fourth message. For example, only the second message may be sent, and the second message may adopt the configuration of the second preamble length and the second data repetition number; or the second message and the third message may be sent, and both the second message and the third message may adopt the configuration of the second preamble length and the second data repetition number; or the second message, the third message, and the fourth message may be sent, and both the second message, the third message, and the fourth message may adopt the configuration of the second preamble length and the second data repetition number, as well as other possible message combinations, which are not limited in this application.

[0155] S205 , when the first initial value satisfies the first value, the second device sends a random access request message to the first device; correspondingly, the first device receives the random access request message.

[0156] The random access request message is used to indicate that contention resolution has been successfully completed for the second device. For example, if the first initial value update value is the first value (e.g., the counter value is 0), indicating that after the second device receives one or more QueryRep requests, the counter is reduced to 0. The second device may then respond with a random access request message. The random access request message includes a random sequence (also known as a random number (RN)), which is used for contention resolution.

[0157] In a possible implementation, if the first device does not receive the random access request message, the first device continues to execute S204.

[0158] In a possible implementation, each QueryRep corresponds to the beginning or end of an access time slot, and the second device may randomly select an access time slot and initiate random access in the corresponding access time slot.

[0159] S206, the first device determines a first preamble code length and a first data repetition number for at least one subsequent downlink transmission.

[0160] S207: The first device sends a first message to at least one second device, and correspondingly, the second device receives the first message.

[0161] The specific implementation of S206 and S207 may refer to the corresponding descriptions of S101 and S102 above, and may also include the following example descriptions:

[0162] In one possible implementation, after the first device receives a random access request message, if there is no collision (for example, only a random access request message sent by a tag is received), the first device may send a UE Contention Resolution Identity message, where the UE Contention Resolution Identity message includes a random sequence received by the first device, indicating that the contention resolution is successful. In this implementation, the first message is a UEContention Resolution Identity message.

[0163] In a possible implementation, the first message adopts the configuration of the second preamble length and the second data repetition number, or adopts the preamble configuration of the last sent QueryRep indication, thereby avoiding misalignment of the preamble configurations of the reader and the tag.

[0164] Optionally, the first message to the fourth message may be broadcast messages. For example, the reader may broadcast at least one of the first message to the fourth message to multiple tags.

[0165] S208: The first device and the second device perform data transmission.

[0166] Among them, after the second device receives the first message, if the random sequence in the first message matches the random sequence of the second device, the first device can transmit data with the second device, for example, the second device sends uplink data to the first device, and the first device sends downlink data to the second device.

[0167] In one possible implementation, a first device receives uplink data from a second device. If the first device successfully receives the data and there is downlink data to be transmitted, the first device continues to send the downlink data to the second device. Alternatively, if the first device successfully receives the data and there is no downlink data to be transmitted, the first device sends a QueryRep to the second device. If the first device fails to receive the data, the first device may resend the downlink data.

[0168] In one possible implementation, if the second device successfully receives the downlink data, it sends uplink data to the first device (for example, an uplink confirmation response, such as the write response corresponding to the write downlink command; or uplink data, such as the read data content of the read downlink command). It is understandable that when the second device sends uplink data to the first device, the first preamble length and the first data repetition count are configured so that the reader and tag are aligned with the preamble configuration.

[0169] In one possible implementation, if the second device sends uplink data to the first device and receives a QueryRep, the data transmission is successful. Alternatively, the reader can trigger the next tag to access, and the current tag completes the data transmission process.

[0170] In one example, the preamble length and data repetition count for the next downlink transmission are determined by the previous downlink transmission. If the preamble length and data repetition count configured by the reader and tag during a transmission are misaligned, the next PDSCH transmission will fail. This error will propagate, resulting in significant air interface resource overhead and transmission delay. Therefore, the following describes several possible scenarios and solutions during S208.

[0171] In one possible implementation, when the first device detects the uplink data and the detection is successful, the first device uses the configuration of the first preamble length and the first data repetition number to send downlink data to the second device, and the second device is the transmitter of the uplink data. For example, in a semi-passive IoT scenario, the tag will not feedback an acknowledgment / non-acknowledgment (ACK / NACK) message. If the reader receives the uplink data, the reader believes that the tag has successfully received the downlink data. Assuming that the previous PDSCH transmission carries the first indication information for indicating the first preamble length and the first data repetition number, if the second device successfully receives the first indication information, the second device can send uplink data to the first device. If the first device detects the uplink data and the detection is successful, it means that the configuration of the preamble length and the data repetition number of the first device and the second device are aligned, and the first device uses the configuration of the first preamble length and the first data repetition number in the next PDSCH transmission.

[0172] In one possible implementation, when the first device detects uplink data and fails, it uses the preamble length and data repetition count configured in the previous downlink transmission to send the downlink data to the second device, which is the transmitter of the uplink data. This implementation may include the following situations:

[0173] Case 1: The second device successfully receives the downlink data and sends the uplink data, but the first device fails to receive it. For example, if the tag successfully receives the downlink data but the reader fails to receive the uplink data, the reader needs to determine whether the tag did not send the uplink data or the tag sent the uplink data but the reader itself failed to receive it. Optionally, the reader can use energy detection to determine whether the tag did not send the uplink data or the tag sent the uplink data but the reader itself failed to receive it; for example, the reader determines the result of the energy detection. If the energy of the received signal is higher than the threshold, but the data does not pass the cyclic redundancy check (CRC), it means that the tag sent the uplink data but the reader itself failed to receive it. In this case, the first device and the second device have aligned the configuration of the preamble length and the number of data repetitions. The first device continues to use the configuration of the first preamble code length and the first number of data repetitions (that is, the previous downlink transmission used the configuration of the first preamble code length and the first number of data repetitions) to send downlink data to the second device.

[0174] Case 2: The second device fails to receive downlink data and does not send uplink data.

[0175] For example, the reader determines the result of energy detection. If the energy of the received signal is lower than the threshold, it means that the tag has not sent uplink data. In this case, the configurations of the preamble length and the number of data repetitions of the first device and the second device may not be aligned. The first device then uses the second preamble length and the second data repetition number (that is, the previous downlink transmission used the default configuration, and this downlink transmission continues to use the default configuration) to send downlink data to the second device.

[0176] In one possible implementation, in addition to the above-mentioned case 1 or case 2, there may also be a situation: when the first device detects the uplink data and the detection is successful, but in fact the second device does not send the uplink data; for example, the noise signal power received by the first device is high, and the cross-correlation between the noise signal sequence and the check sequence of the first device is high, then the first device believes that the uplink data is received successfully. However, in fact, the second device does not send the uplink data, and the configuration of the preamble length and the number of data repetitions of the first device and the second device may not be aligned. At this time, the first device uses the configuration of the first preamble length and the first data repetition number (that is, the previous downlink transmission uses the configuration of the first preamble length and the first data repetition number, and this downlink transmission continues to use the configuration of the first preamble length and the first data repetition number) to send the downlink data to the second device. Correspondingly, the second device may not use the configuration of the first preamble length and the first data repetition number, then the second device cannot correctly receive the downlink data, and the data transmission between the first device and the second device is invalid transmission. To avoid multiple invalid transmissions, this application defines a first time length. If the first device fails to detect uplink data after exceeding the first time length, the downlink data is sent to the second device using a second preamble length and a second number of data repetitions. For example, both the reader and the tag set a maximum time window (the length of the maximum time window is the first time length). If the maximum time window is exceeded, the default configuration is restored.

[0177] In one possible implementation, the first time length is determined based on the maximum time length between two adjacent downlink messages. For example, the protocol specifies a maximum time window, and the value may depend on: the maximum time length between two adjacent downlink messages, such as the maximum time length between two QueryReps, to prevent the tag from missing the QueryRep / Query (the last access time slot) reception due to not obtaining the latest preamble configuration (error decoding or non-reception), thereby preventing the tag from missing a new access opportunity / time slot. Another example is the maximum time length between two Queries, to prevent the tag from missing the Query reception due to not obtaining the latest preamble configuration, thereby preventing the tag from missing a new round of inventory / access process. It should be noted that two adjacent downlink messages refer to two downlink messages sent consecutively in time, for example, there are no other downlink messages from the same base station between the two downlink messages.

[0178] In one possible implementation, the first time length is determined based on the coverage level of the first device. For example, if the coverage level of the first device is low (such as far coverage or poor coverage), the first time length is set to a larger value; if the coverage level of the first device is high (such as small coverage, excellent coverage), the first time length is set to a smaller value. It can be understood that the uplink and downlink modulation and coding schemes (MCS) corresponding to the coverage level are different, so the time length of the uplink and downlink messages is related to the coverage level, and the first device can calculate the first time length based on the specific MCS configuration. Optionally, MCS-related configurations may include but are not limited to: preamble length, number of level repetitions, code rate, etc.

[0179] In one possible implementation, the first time length is determined based on the type of the second device. For example, the encoding methods of passive tags and semi-passive / active tags are different, resulting in different signaling time lengths. Therefore, the first time lengths corresponding to different types of tags are different. For example, passive tags only support convolutional codes, while semi-passive / active tags can support polar codes. Different device types have different physical layer parameters such as encoding methods, so the first time lengths may also be different.

[0180] In one possible implementation, the first device may dynamically configure the first time length, or define a first time length set, the first time length set including a plurality of maximum time windows, and may dynamically select one of the values as the value of the current first time length. For example, the values of the plurality of maximum time windows may be similar to those in the above implementation (i.e., the time length between two adjacent downlink messages, which is related to the coverage level, label type, etc.). The specific configuration method of the first time length may be similar to the configuration of the preamble length (physical layer or high-layer indication), which is not limited in this application.

[0181] It is understood that in order to implement the functions of the above-mentioned device embodiments, the base station and the terminal include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in conjunction with the various exemplary units and method steps described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a computer software-driven hardware manner depends on the specific application scenario and design constraints of the technical solution.

[0182] Figure 4 and Figure 5 Schematic diagrams of possible communication devices provided by this application. These communication devices can be used to implement the functions of the terminal or base station in the above method embodiments, and thus can also achieve the beneficial effects possessed by the above method embodiments.

[0183] like Figure 4 As shown, the communication device 400 includes a processing unit 410 and a transceiver unit 420. The communication device 400 is used to implement the above Figure 2 and Figure 3 Optionally, the transceiver unit 420 includes a transmitting unit and a receiving unit, and the transceiver unit 420 may also be referred to as a communication unit.

[0184] When the communication device 400 is used to implement Figure 2 and Figure 3 In the illustrated method embodiment, the base station functions as follows: processing unit 410 is configured to determine a first preamble length and a first number of data repetitions for at least one subsequent downlink transmission. Transceiver unit 420 transmits a first message to at least one second device, the first message including first indication information indicating a first preamble length and a first number of data repetitions for at least one subsequent downlink transmission by the first device.

[0185] In one possible implementation, the transceiver unit 420 is further configured to:

[0186] When the first device detects the uplink data and the detection is successful, the downlink data is sent to the second device using the configuration of the first preamble code length and the first data repetition number.

[0187] In one possible implementation, the transceiver unit 420 is further configured to:

[0188] When the first device detects the uplink data and fails, the downlink data is sent to the second device using the configuration of the preamble length and the number of data repetitions of the previous downlink transmission.

[0189] In one possible implementation, the transceiver unit 420 is further configured to:

[0190] If the first device fails to detect the uplink data after exceeding the first time length, the downlink data is sent to the second device using a second preamble length and a second data repetition number.

[0191] In a possible implementation, the transceiver unit 420 is further configured to:

[0192] sending a second message to at least one second device, where the second message is used to page or select one or more second devices;

[0193] sending a third message to at least one second device, where the third message is used to indicate a number of random access opportunities;

[0194] A fourth message is sent to at least one second device, where the fourth message is used to indicate a random access opportunity; wherein the second message, the third message, and the fourth message all adopt a configuration of a second preamble code length and a second number of data repetitions.

[0195] In a possible implementation, the transceiver unit 420 is further configured to:

[0196] A random access request message is received from at least one second device, where the random access request message indicates that contention resolution for the at least one second device is successful; the first message also includes the random access request message.

[0197] It can be seen that when the communication device 400 is used to implement Figure 2 and Figure 3 When the base station functions in the method embodiment shown, the communication device 400 can indicate to at least one second device through a first message the first preamble code length and the first data repetition number of subsequent downlink transmissions for at least one subsequent downlink transmission, so that the preamble configuration of the reader and the tag is aligned, avoiding the flattening of the error detection rate caused by blind detection of preambbles of different lengths.

[0198] When the communication device 400 is used to implement Figure 2 and Figure 3 In the illustrated method embodiment, the terminal functions as follows: a transceiver unit 420 is configured to receive a first message from a first device, the first message including first indication information, the first indication information being configured to indicate a first preamble length and a first data repetition count for at least one subsequent downlink transmission by the first device. A processing unit 410 is configured to apply the configuration of the first preamble length and the first data repetition count.

[0199] In a possible implementation, the transceiver unit 420 is further configured to:

[0200] sending uplink data to the first device;

[0201] When the first device detects the uplink data and the detection is successful, downlink data from the first device is received, where the downlink data is generated by the first device using a configuration of a first preamble length and a first number of data repetitions.

[0202] In a possible implementation, the transceiver unit 420 is further configured to:

[0203] sending uplink data to the first device;

[0204] When the first device detects the uplink data and fails, it receives downlink data from the first device, where the downlink data is generated by the first device using the configuration of the preamble length and data repetition times of the previous downlink transmission.

[0205] In one possible implementation, the transceiver unit 420 is further configured to:

[0206] receiving a second message, the second message being used to page or select one or more second devices;

[0207] receiving a third message, the third message being used to indicate a number of random access opportunities;

[0208] A fourth message is received, where the fourth message is used to indicate a random access opportunity; wherein the second message, the third message, and the fourth message all adopt a configuration of a second preamble length and a second number of data repetitions.

[0209] In a possible implementation, the processing unit 410 is further configured to: determine a first initial value based on the number of random access opportunities; the first initial value is updated based on the number of times the second apparatus receives the fourth message;

[0210] The transceiver unit 420 is further configured to: when the first initial value satisfies the first value, send a random access request message to the first device, where the random access request message is used to indicate that contention resolution for the second device is successful.

[0211] It can be seen that when the communication device 400 is used to implement Figure 2 and Figure 3 When the terminal functions in the method embodiment shown, the communication device 400 receives the first message and can determine the first preamble code length and the first data repetition number of at least one subsequent downlink transmission, so that the preamble configuration of the reader and the tag are aligned, avoiding blind detection of preambles of different lengths resulting in a flat error detection rate.

[0212] For more detailed description of the processing unit 410 and the transceiver unit 420, please refer to Figure 2 and Figure 3 The method embodiment shown is described in detail.

[0213] like Figure 5 As shown, the communication device 500 includes a processor 510 and an interface circuit 520. The processor 510 and the interface circuit 520 are coupled to each other. It is understood that the interface circuit 520 can be a transceiver or an input / output interface. Optionally, the communication device 500 may also include a memory 530 for storing instructions executed by the processor 510, or storing input data required by the processor 510 to execute instructions, or storing data generated after the processor 510 executes instructions. Sometimes, the interface circuit 520 can also be understood as part of the processor 510, in which case the communication device 500 includes the processor 510. Optionally, the transceiver includes a transmitter and a receiver.

[0214] When the communication device 500 is used to implement Figure 2 and Figure 3When the method is shown, the processor 510 is used to implement the functions of the processing unit 410, and the interface circuit 520 is used to implement the functions of the transceiver unit 420.

[0215] When the above-mentioned communication device is a chip applied to a terminal, the terminal chip implements the functions of the terminal in the above-mentioned method embodiment. When the terminal chip receives information from the base station, it can be understood that the information is first received by other modules in the terminal (such as a radio frequency module or antenna) and then sent to the terminal chip by these modules. When the terminal chip sends information to the base station, it can be understood that the information is first sent to other modules in the terminal (such as a radio frequency module or antenna) and then sent to the base station by these modules.

[0216] When the above-mentioned communication device is a chip applied to a base station, the base station chip implements the functions of the base station in the above-mentioned method embodiment. When the base station chip receives information from the terminal, it can be understood that the information is first received by other modules in the base station (such as a radio frequency module or antenna) and then sent to the base station chip by these modules. When the base station chip sends information to the terminal, it can be understood that the information is sent to other modules in the base station (such as a radio frequency module or antenna) and then sent to the terminal by these modules.

[0217] In this application, when entity A sends information to entity B, it can be done directly from A to B or indirectly through another entity. Similarly, when entity B receives information from entity A, it can be done directly from entity B or indirectly through another entity. Entities A and B herein can be RAN nodes or terminals, or modules within a RAN node or terminal. The sending and receiving of information can be information exchange between a RAN node and a terminal, for example, between a base station and a terminal; the sending and receiving of information can also be information exchange between two RAN nodes, for example, between a CU and a DU; the sending and receiving of information can also be information exchange between different modules within a device, for example, between a terminal chip and other modules in the terminal, or between a base station chip and other modules within the base station.

[0218] In other words, sending and receiving can be performed between devices, for example, between a network device and a terminal device, or can be performed within a device, for example, sending or receiving between components, modules, chips, software modules or hardware modules within the device through a bus, wiring or interface.

[0219] It is understandable that information may be processed between the source and destination of information transmission, such as coding, modulation, etc., but the destination can understand the valid information from the source. Similar expressions in this application can be understood similarly and will not be repeated.

[0220] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0221] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and storage medium can also exist in a base station or a terminal as discrete components.

[0222] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0223] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0224] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0225] In this application, words such as "first" and "second" can be used to distinguish technical features with the same or similar functions. The words such as "first" and "second" do not limit the quantity and execution order, and the words such as "first" and "second" do not necessarily limit them to be different. In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or design. The use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0226] In the embodiments of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the indication information described below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association between the other information and the information to be indicated; it is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance, for example, the indication of specific information can be achieved with the help of the arrangement order of each information agreed in advance (such as predefined by the protocol), thereby reducing the indication overhead to a certain extent. The present application does not limit the specific method of indication. It is understandable that, for the sender of the indication information, the indication information can be used to indicate the information to be indicated, and for the receiver of the indication information, the indication information can be used to determine the information to be indicated.

[0227] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A communication method, characterized in that: The method comprises: Determining a first preamble length and a first data repetition number for at least one subsequent downlink transmission; A first message is sent to at least one second device, where the first message includes first indication information, and the first indication information is used to indicate a first preamble code length and a first data repetition number for at least one subsequent downlink transmission by the first device.

2. The method according to claim 1, characterized in that There is a first mapping relationship between the preamble length and the index of the preamble length, and there is a second mapping relationship between the number of data repetitions and the index of the number of data repetitions; The first indication information includes an index of a first preamble length and an index of a first data repetition number.

3. The method according to claim 1, characterized in that There is a third mapping relationship between the change in the preamble length of two adjacent downlink transmissions and the index of the change in the preamble length, and there is a fourth mapping relationship between the change in the number of data repetitions and the index of the change in the number of data repetitions; The first indication information includes an index of a change in the length of the first preamble code and an index of a change in the number of first data repetitions; The first preamble length is determined based on the preamble length of the previous downlink transmission and the change in the first preamble length, and the first data repetition number is determined based on the data repetition number of the previous downlink transmission and the change in the first data repetition number.

4. The method according to any one of claims 1 to 3, characterized in that The first message further includes second indication information, where the second indication information is used to indicate at least one of a first midamble length or a first postamble length for at least one subsequent downlink transmission by the first device; There is a fifth mapping relationship between the midamble length and the index of the midamble length, and a sixth mapping relationship between the postamble length and the index of the postamble length, and the second indication information includes at least one of the index of the first midamble length or the index of the first postamble length.

5. The method according to any one of claims 1 to 3, characterized in that There is a seventh mapping relationship between the midamble length and the preamble length, and there is an eighth mapping relationship between the postamble length and the preamble length.

6. The method according to claim 1, characterized in that The method further comprises: When the first device detects the uplink data and the detection is successful, the first preamble code length and the first data repetition number are configured to send the downlink data to the second device, which is the transmitter of the uplink data.

7. The method according to claim 1, characterized in that The method further comprises: When the first device detects the uplink data and fails, it uses the configuration of the preamble length and data repetition times of the previous downlink transmission to send the downlink data to the second device, which is the transmitter of the uplink data.

8. The method according to claim 7, characterized in that The method further comprises: If the first device fails to detect the uplink data after exceeding the first time length, sending the downlink data to the second device using a second preamble length and a second data repetition number; The second preamble length is the maximum preamble length in the first mapping relationship, and the second data repetition number is the maximum data repetition number in the second mapping relationship.

9. The method according to claim 8, characterized in that The first time length is determined based on the maximum time length between two adjacent downlink messages; or, the first time length is determined based on the coverage level of the first device; or, the first time length is determined based on the type of the second device.

10. The method according to claim 1, characterized in that Before sending the first message to at least one second device, the method further includes: sending a second message to at least one second device, wherein the second message is used to page or select one or more second devices; sending a third message to at least one second device, where the third message is used to indicate a number of random access opportunities; sending a fourth message to at least one second device, where the fourth message is used to indicate a random access opportunity; The second message, the third message and the fourth message all adopt the configuration of the second preamble length and the second data repetition number; The second preamble length is the maximum preamble length in the first mapping relationship, and the second data repetition number is the maximum data repetition number in the second mapping relationship.

11. The method according to claim 10, characterized in that The method further comprises: receiving a random access request message from at least one second device, the random access request message indicating that contention resolution for the at least one second device is successful; The first message also includes the random access request message.

12. A communication method, characterized in that: The method comprises: receiving a first message from a first device, where the first message includes first indication information, where the first indication information is used to indicate a first preamble length and a first data repetition count for at least one subsequent downlink transmission by the first device; The configuration of the first preamble length and the first number of data repetitions is applied.

13. The method according to claim 12, characterized in that There is a first mapping relationship between the preamble length and the index of the preamble length, and there is a second mapping relationship between the number of data repetitions and the index of the number of data repetitions; The first indication information includes an index of a first preamble length and an index of a first data repetition number.

14. The method according to claim 12, characterized in that There is a third mapping relationship between the change in the preamble length of two adjacent downlink transmissions and the index of the change in the preamble length, and there is a fourth mapping relationship between the change in the number of data repetitions and the index of the change in the number of data repetitions; The first indication information includes an index of a change in the length of the first preamble code and an index of a change in the number of first data repetitions; The first preamble length is determined based on the preamble length of the previous downlink transmission and the change in the first preamble length, and the first data repetition number is determined based on the data repetition number of the previous downlink transmission and the change in the first data repetition number.

15. The method according to any one of claims 12 to 14, characterized in that The first message further includes second indication information, where the second indication information is used to indicate at least one of a first midamble length or a first postamble length for at least one subsequent downlink transmission by the first device; There is a fifth mapping relationship between the midamble length and the index of the midamble length, and a sixth mapping relationship between the postamble length and the index of the postamble length, and the second indication information includes at least one of the index of the first midamble length or the index of the first postamble length.

16. The method according to any one of claims 12 to 14, characterized in that There is a seventh mapping relationship between the midamble length or the postamble length and the preamble length, and there is an eighth mapping relationship between the postamble length and the preamble length.

17. The method according to claim 12, characterized in that The method further comprises: sending uplink data to the first device; When the first device detects the uplink data and the detection is successful, downlink data from the first device is received, where the downlink data is generated by the first device using the configuration of the first preamble length and the first number of data repetitions.

18. The method according to claim 12, wherein: The method further comprises: sending uplink data to the first device; When the first device detects the uplink data and fails, it receives downlink data from the first device, where the downlink data is downlink data generated by the first device using the configuration of the preamble length and data repetition times of the previous downlink transmission.

19. The method according to claim 12, wherein: Before receiving the first message from the first device, the method further includes: receiving a second message for paging or selecting one or more second devices; receiving a third message, where the third message is used to indicate a number of random access opportunities; receiving a fourth message, where the fourth message is used to indicate a random access opportunity; The second message, the third message and the fourth message all adopt the configuration of the second preamble length and the second data repetition number; The second preamble length is the maximum preamble length in the first mapping relationship, and the second data repetition number is the maximum data repetition number in the second mapping relationship.

20. The method according to claim 19, characterized in that The method further comprises: determining a first initial value based on the number of random access opportunities; and updating the first initial value based on the number of times the second device receives a fourth message. When the first initial value satisfies a first value, a random access request message is sent to the first device, where the random access request message is used to indicate that contention resolution for the second device is successful.

21. A communication device, characterized in that: The method comprises modules or units for executing the method according to any one of claims 1 to 11.

22. A communication device, characterized in that: The method comprises modules or units for executing the method according to any one of claims 12 to 20.

23. A communication device, characterized in that: The communication device comprises a memory and one or more processors, wherein the memory is used to store a computer program; the one or more processors are used to execute the computer program in the memory, so that the communication device performs the method according to any one of claims 1 to 11.

24. A communication device, characterized in that: The communication device comprises a memory and one or more processors, wherein the memory is used to store a computer program; the one or more processors are used to execute the computer program in the memory, so that the communication device performs the method according to any one of claims 12 to 20.

25. A communication system, characterized in that: The communication system includes the communication device according to claim 21 or 23, and the communication device according to claim 22 or 24.

26. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program or instructions. When the computer program or instructions are executed by a computer, the method according to any one of claims 1 to 11 or claims 12 to 20 is implemented.

27. A chip, characterized in that: The chip includes a processor configured to execute a computer program, so that the chip implements the method according to any one of claims 1 to 11 or claims 12 to 20.

28. A chip system, characterized in that: The chip system includes a processor and an interface, and the processor is used to execute a computer program so that the chip system implements the method according to any one of claims 1 to 11 or claims 12 to 20.

29. A computer program product, characterized in that The method comprises instructions which, when executed on a computer, cause the computer to perform the method according to any one of claims 1 to 11 or claims 12 to 20.

Images