Communication method and apparatus

Abstract

A communication method and apparatus. The method comprises: newly adding a reference signal (for example, referred to as a first reference signal) to a message A, a time domain interval between the first reference signal and a second reference signal (DMRS) being less than a time domain interval between the second reference signal (DMRS) and a first random access preamble. For example, the first reference signal is sent between the first random access preamble and the second reference signal (DMRS). Thus, the time domain positions of the first reference signal and the second reference signal are closer. In this case, in the time domain interval between the first reference signal and the second reference signal, the probability that a phase jump occurs in a component such as a PA of a transmitter comprised in a terminal device decreases, and the probability that phases of the first reference signal and the second reference signal are continuous is higher, thereby improving the probability that uplink data is successfully demodulated, and improving demodulation performance of a PUSCH.

Description

Communication method and apparatus

[0001] Cross-reference to related applications

[0002] This application claims priority to the Chinese Patent Application No. 202510221710.5, filed on February 26, 2025, and entitled "A communication method and apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of communication technology, and in particular to a communication method and apparatus. BACKGROUND

[0004] In the new radio (NR) of 5G, a two-step random access method is proposed, which can simplify the access process of the terminal device, reduce the signaling overhead and delay compared with the four-step random access method. In the two-step random access method, the terminal device sends message A; the access network device receives message A and sends message B in response to message A. In the current method, message A contains a random access preamble and a physical uplink shared channel (PUSCH), and the PUSCH contains a reference signal (such as DMRS) and uplink data. The access network device can demodulate the uplink data using the reference signal. Since the demodulation performance of the uplink data contained in the PUSCH affects the access delay of the terminal device, how to improve the demodulation performance of the uplink data contained in the PUSCH is a problem to be solved. SUMMARY

[0005] The present application provides a communication method and apparatus to improve the demodulation performance of the uplink data contained in the PUSCH (or simply referred to as improving the demodulation performance of the PUSCH) and reduce the access delay of the terminal device.

[0006] In a first aspect, a communication method is provided, which can be applied to a terminal device side, such as a terminal device or a communication module and / or a computing module in the terminal device, or a circuit or a chip responsible for communication functions in the terminal device (such as a modem chip, also known as a baseband chip, or a system on chip (SoC) chip or a system in package (SIP) chip containing a modem core, or a circuit or a chip responsible for communication and / or computing functions in the terminal device (such as a graphics processing unit (GPU), an artificial intelligence (AI) processor, or an application specific integrated circuit (ASIC)), or a logic node, a logic module, or software capable of realizing all or part of the functions of the terminal device. The method comprises: sending a message A, the message A comprising a first random access preamble, a first reference signal, and a physical uplink shared channel (PUSCH), the PUSCH comprising a first uplink data and a second reference signal, the first reference signal and the second reference signal being used for demodulating the first uplink data, the time domain interval between the second reference signal and the first reference signal being less than the time domain interval between the second reference signal and the first random access preamble; and receiving a message B, the message B being in response to the message A, the message B being used for indicating that the terminal device successfully performs random access, or being used for indicating to fall back to a four-step random access.

[0007] Through the above design, a reference signal (referred to as a first reference signal) is added in the message A, the time domain interval between the first reference signal and a second reference signal (DMRS) is less than the time domain interval between the second reference signal (DMRS) and a first random access preamble (preamble), and the first reference signal is sent between the first random access preamble (preamble) and the second reference signal (DMRS). The time domain positions of the first reference signal and the second reference signal are closer. The probability of phase jump of a PA and other devices of a transmitter included in the terminal device within the time domain interval between the first reference signal and the second reference signal is low, and the probability of phase continuity of the first reference signal and the second reference signal is higher than the probability of phase continuity of the first random access preamble (preamble) and the second reference signal, thereby improving the probability of successful demodulation of the uplink data and improving the demodulation performance of the PUSCH.

[0008] In a possible implementation, the time domain interval between the first reference signal and the second reference signal is less than or equal to a first threshold, and the first threshold is predefined or preconfigured.

[0009] In a possible implementation, the first reference signal and the second reference signal satisfy at least one of the following characteristics: a sequence of the first reference signal is consistent with a sequence of the second reference signal in terms of cross-correlation statistical characteristics; the first reference signal and the second reference signal have the same transmission power, or a difference between the transmission powers of the two is a known value; the first reference signal and the second reference signal have the same transmission beam; a frequency domain interval of the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidths occupied by the two belong to a same coherence bandwidth, in which a channel characteristic of a channel has correlation; and a mapping relationship between the first random access preamble and the first reference signal is the same as a mapping relationship between the first random access preamble and the second reference signal.

[0010] In a possible implementation, the first reference signal and the second reference signal are frequency division multiplexed, and a frequency domain interval of the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidths occupied by the two belong to a same coherence bandwidth, in which a channel characteristic of a channel has correlation.

[0011] In a possible implementation, the first reference signal and the second reference signal satisfy at least one of the following characteristics: a sequence of the first reference signal is consistent with a sequence of the second reference signal in terms of cross-correlation statistical characteristics; the first reference signal and the second reference signal have the same transmission power, or a difference between the transmission powers of the two is a known value; the first reference signal and the second reference signal have the same transmission beam; and a mapping relationship between the first random access preamble and the first reference signal is the same as a mapping relationship between the first random access preamble and the second reference signal.

[0012] In a possible implementation, the sequence of the first reference signal is consistent with the sequence of the second reference signal in terms of cross-correlation statistical characteristics, including:

[0013] The first reference signal corresponds to a first sequence, the first sequence belongs to a first sequence set, the second reference signal corresponds to a second sequence, the second sequence belongs to a second sequence set, and a cross-correlation mean value of the first sequence set and the second sequence set is the same.

[0014] In a possible implementation, the first reference signal and the second reference signal are code division multiplexed.

[0015] The first reference signal corresponds to a first sequence, the second reference signal corresponds to a second sequence, the first sequence belongs to a first sequence set, the second sequence belongs to a second sequence set, the first sequence and the second sequence belong to a third sequence set, and a cross-correlation mean of the third sequence set, the first sequence set and the second sequence set is the same.

[0016] In a possible implementation, at least one of the following conditions is met between the first reference signal and the second reference signal: the first reference signal and the second reference signal have the same transmission power, or the difference between the transmission powers of the two is a known value; and the first reference signal and the second reference signal have the same transmission beam.

[0017] In a possible implementation, the method further includes determining that a first condition is met, wherein the first condition includes that a reference signal received power (RSRP) of a received system message is less than or equal to a fourth threshold value, and / or an index of a modulation and coding scheme (MCS) of uplink data is greater than or equal to a fifth threshold value.

[0018] Through the above design, the first condition can be considered as a condition that the channel quality of the current channel is poor, or the first condition can be considered as a condition that the channel quality of the current channel is required to be high, and therefore, in the above scenario, the terminal device transmits the first reference signal, and accordingly, the access network device can jointly demodulate the first uplink data based on the first reference signal and the second reference signal, thereby improving the demodulation performance of the first PUSCH.

[0019] In a possible implementation, the first random access preamble is used to indicate whether the first reference signal is transmitted.

[0020] The second aspect is a method opposite to the first aspect, and the beneficial effects can be referred to the description of the first aspect. A communication method is provided, which can be applied to the network side, such as an access network device of the network side, a module (such as a circuit, a chip or a chip system, etc.) in the access network device, or a logic node, a logic module or software capable of realizing all or part of the functions of the access network device, or a circuit or chip (such as a GPU, an AI processor, or an ASIC) responsible for communication and / or computing functions in the access network device. The method includes: receiving a message A, the message A containing a first random access preamble, a first reference signal and a physical uplink shared channel (PUSCH), the PUSCH containing first uplink data and a second reference signal, the first reference signal and the second reference signal being used to demodulate the first uplink data, and a time domain interval between the second reference signal and the first reference signal being less than a time domain interval between the second reference signal and the first random access preamble; and sending a message B, the message B being a corresponding of the message A, the message B being used to indicate that the terminal device successfully performs random access, or being used to indicate that the terminal device falls back to four-step random access.

[0021] In a possible implementation, a time domain interval between the first reference signal and the second reference signal is less than or equal to a first threshold, and the first threshold is predefined or preconfigured.

[0022] In a possible implementation, at least one of the following characteristics is satisfied between the first reference signal and the second reference signal: a sequence of the first reference signal is consistent with a cross-correlation statistical characteristic of a sequence of the second reference signal; a transmission power of the first reference signal is same as a transmission power of the second reference signal, or a difference between the transmission power of the first reference signal and the transmission power of the second reference signal is a known value; a transmission beam of the first reference signal is same as a transmission beam of the second reference signal; a frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or a bandwidth occupied by the first reference signal is same as a bandwidth occupied by the second reference signal, or the bandwidth occupied by the first reference signal and the bandwidth occupied by the second reference signal belong to a same coherence bandwidth, and a channel characteristic of a channel within the same coherence bandwidth has a correlation; and a mapping relationship between the first random access preamble and the first reference signal is same as a mapping relationship between the first random access preamble and the second reference signal.

[0023] In a possible implementation, a relationship between the first reference signal and the second reference signal is frequency division multiplexing, and a frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or a bandwidth occupied by the first reference signal is same as a bandwidth occupied by the second reference signal, or the bandwidth occupied by the first reference signal and the bandwidth occupied by the second reference signal belong to a same coherence bandwidth, and a channel characteristic of a channel within the same coherence bandwidth has a correlation.

[0024] In a possible implementation, at least one of the following characteristics is satisfied between the first reference signal and the second reference signal: a sequence of the first reference signal is consistent with a cross-correlation statistical characteristic of a sequence of the second reference signal; a transmission power of the first reference signal is same as a transmission power of the second reference signal, or a difference between the transmission power of the first reference signal and the transmission power of the second reference signal is a known value; a transmission beam of the first reference signal is same as a transmission beam of the second reference signal; and a mapping relationship between the first random access preamble and the first reference signal is same as a mapping relationship between the first random access preamble and the second reference signal.

[0025] In a possible implementation, a sequence of the first reference signal is consistent with a cross-correlation statistical characteristic of a sequence of the second reference signal, including that the first reference signal corresponds to a first sequence, the first sequence belongs to a first sequence set, the second reference signal corresponds to a second sequence, the second sequence belongs to a second sequence set, and a cross-correlation mean value of the first sequence set and the second sequence set is same.

[0026] In a possible implementation, the first reference signal and the second reference signal are code division multiplexed.

[0027] In a possible implementation, the first reference signal corresponds to a first sequence, and the second reference signal corresponds to a second sequence, the first sequence belongs to a first sequence set, the second sequence belongs to a second sequence set, the first sequence and the second sequence belong to a third sequence set, and the third sequence set, the first sequence set, and the second sequence set have the same cross-correlation mean.

[0028] In a possible implementation, the first reference signal and the second reference signal satisfy at least one of the following characteristics: the first reference signal and the second reference signal have the same transmission power, or the difference between the transmission powers of the two is a known value; or the first reference signal and the second reference signal have the same transmission beam.

[0029] In a possible implementation, the first reference signal is transmitted when a first condition is met, and the first condition includes: the received reference signal received power (RSRP) of a system message is less than or equal to a fourth threshold value, and / or the index of a modulation and coding scheme (MCS) of uplink data is greater than or equal to a fifth threshold value.

[0030] In a possible implementation, the first random access preamble is used to indicate whether the first reference signal is transmitted.

[0031] In a third aspect, an apparatus is provided, which can implement the method in the first aspect. For example, the apparatus includes modules, units, or components corresponding to the method described in the first aspect. The modules, units, or components can be implemented by hardware, or by software, or by a combination of hardware and software.

[0032] In a design, the apparatus includes units for implementing the method in the first aspect.

[0033] In a design, the apparatus includes a processor for implementing the method in the first aspect. Optionally, the apparatus further includes a memory coupled to the processor, and the processor is configured to execute computer programs or instructions stored in the memory, so that the apparatus implements the method in the first aspect.

[0034] In a design, the apparatus includes a processor and an interface circuit, the interface circuit is configured to receive signals from other apparatuses outside the apparatus and transmit the signals to the processor, or transmit signals from the processor to other apparatuses outside the apparatus, and the processor is configured to implement the method in the first aspect by logic circuit or executing code instructions.

[0035] In an embodiment, the apparatus can be the first apparatus, or a module, unit or component (e.g., a chip, chip system, circuit, or processor, etc.) in the first apparatus that performs the method / operation / step / action described in the first aspect, or is capable of being matched with the first apparatus.

[0036] In a fourth aspect, an apparatus is provided, which is capable of implementing the method described in the second aspect. For example, the apparatus includes a module, unit, or component that performs the method described in the second aspect. The module, unit, or component can be implemented by hardware, or by software, or by a combination of hardware and software.

[0037] In an embodiment, the apparatus includes a unit that performs the method described in the second aspect.

[0038] In an embodiment, the apparatus includes a processor that is configured to implement the method described in the second aspect. Optionally, the apparatus further includes a memory, and the processor is coupled to the memory, and is configured to execute a computer program or instructions stored in the memory, so that the apparatus implements the method described in the second aspect.

[0039] In an embodiment, the apparatus includes a processor and an interface circuit, the interface circuit is configured to receive a signal from another apparatus outside the apparatus and transmit the signal to the processor, or transmit a signal from the processor to another apparatus outside the apparatus, and the processor is configured to implement the method described in the second aspect by means of a logic circuit or executing code instructions.

[0040] In an embodiment, the apparatus can be the second apparatus, or a module, unit or component (e.g., a chip, chip system, circuit, or processor, etc.) in the second apparatus that performs the method / operation / step / action described in the second aspect, or is capable of being matched with the second apparatus.

[0041] In a fifth aspect, a computer readable storage medium is provided, which stores a computer program or instructions, when the computer program or instructions are run on a computer, the computer implements the method described in the first aspect or the second aspect.

[0042] In a sixth aspect, a computer program product is provided, which includes a computer program or instructions, when the computer program or instructions are run on a computer, the method described in the first aspect or the second aspect is executed.

[0043] In a seventh aspect, a chip is provided, which includes a processor that is configured to implement the method described in the first aspect or the second aspect. Optionally, the chip further includes a memory, and the processor is coupled to the memory, and is configured to execute a computer program or instructions stored in the memory, so that the chip implements the method described in the first aspect or the second aspect.

[0044] In an eighth aspect, a communication system is provided, comprising: a first communication device and a second communication device; wherein the first communication device is configured to implement the method of the first aspect; and the second communication device is configured to implement the method of the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0045] FIG. 1 is a schematic diagram of a communication system according to the present application;

[0046] FIG. 2 is a schematic diagram of an ORAN system according to the present application;

[0047] FIG. 3 is a schematic diagram of the network element function division and protocol layer structure of an O-RAN device according to the present application;

[0048] FIG. 4 is a schematic diagram of a two-step random access method according to the present application;

[0049] FIG. 5 is a schematic diagram of the time domain resources occupied by PRACH and PUCSH according to the present application;

[0050] FIG. 6 is a schematic diagram of a communication method according to the present application;

[0051] FIG. 7a and FIG. 7b are schematic diagrams of the mapping relationship between preamble and PRU according to the present application;

[0052] FIG. 8 is a schematic diagram of a first sequence set and a second sequence set according to the present application;

[0053] FIG. 9a and FIG. 9b are schematic diagrams of the mapping relationship between preamble, first reference signal and PRU according to the present application;

[0054] FIG. 10 is a schematic diagram of a first sequence set, a second sequence set and a third sequence set according to the present application;

[0055] FIG. 11 and FIG. 12 are schematic diagrams of the structure of a device according to the present application. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application are described in further detail below with reference to the drawings. The specific operation methods, function descriptions and the like in the method embodiments can also be applied to the device embodiments or system embodiments.

[0057] In the description of the present application, the number of nouns is "singular or plural", that is, "one or more" unless otherwise specified. "At least one" means one or more, and "multiple" means two or more. The association relationship of the associated objects is described as "and / or", which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. In the textual description of the present application, the character " / " generally represents an "or" relationship between the associated objects before and after it; in the formula of the present application, the character " / " represents a "division" relationship between the associated objects before and after it. "Including at least one of A, B or C" or similar expressions 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, where A, B, C can be singular or plural.

[0058] In the description of the present application, various numbers are distinguished for the convenience of description, and are not used to limit the scope of the embodiments of the present application. The size of the serial number of the above processes does not mean the order of execution, and the execution order of the processes should be determined according to their functions and internal logic. The ordinal numbers "first", "second", etc. involved in the embodiments of the present application are used to distinguish a plurality of objects, and do not limit the size, order, time sequence, priority or importance of the plurality of objects.

[0059] In the description of the present application, the numbering of steps in each flowchart is only for the purpose of distinguishing different steps, and is not used to limit the order of the steps. The steps contained in each flowchart are not limited, and each flowchart can contain more steps or fewer steps, and multiple steps can be combined into one step, or one step can be split into multiple steps, etc. The descriptions related in different flowcharts can be referred to each other. The arrows or blocks shown by dashed lines in each flowchart represent optional steps or optional modules.

[0060] In the description of the present application, "sending" or "receiving" represents the direction of information / signal. "Sending" or "receiving" can also be understood as "input" or "output". For example, "sending" or "receiving" can be carried out between devices, such as terminal devices and access network devices, through a wireless channel for sending or receiving respectively, and "sending" or "receiving" can also be carried out inside a device, such as between components, modules, chips, software modules or hardware modules in a device through a bus, wire or interface. For example, "sending" can also be understood as the "output" of a chip interface, and "receiving" can also be understood as the "input" of a chip interface.

[0061] Five, in the description of the present application, "sending information (such as first information) to (such as terminal device)" can be understood as that the destination of the information is the terminal device. It can include direct or indirect sending information to (such as terminal device). "Receiving information (such as second information or third information) from (such as access network device)" can be understood as that the source of the information is the access network device, which can include direct or indirect receiving information from the access network device. The information between the source and the destination of the information sending can be processed as necessary, such as format change, etc., but the destination can understand the effective information from the source. Similar expressions in the present application can be understood similarly, and will not be repeated here.

[0062] Six, in the description of the present application, "for indicating" can include for directly indicating (or showing indicating) and for indirectly indicating (or implicitly indicating). For example, when describing that certain indicating information is used to indicate information I, it can include that the indicating information directly indicates I or indirectly indicates I, and it does not mean that I must be carried in the indicating information.

[0063] Seven, in the description of the present application, "when", "if" and "if" all refer to the device will make corresponding processing under certain objective circumstances, not limited to time, and also does not require the device to realize the judgment action, and also does not mean that there are other limitations. Unless otherwise specified, "if" and "if" can be replaced, "when" and "in the case" can be replaced, "when" can also be replaced by: "when", or "after" and so on, "when" can also be replaced with "if" / "if" and so on. The words such as "exemplary" or "for example" are used to represent as an example, illustration or description. Any embodiment or design scheme described as "exemplary" or "for example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Exactly, the words such as "exemplary" or "for example" are intended to present the related concept in a specific way.

[0064] Eight, in the description of the present application: the terms "system" and "network" can be used interchangeably, "according to" and "based on" can be used interchangeably. The terms "include", "contain" and "have" and their any variations are intended to cover non-exclusive inclusion, for example, the process, method, system, product or device containing a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units which are not clearly listed or inherent to these processes, methods, products or devices.

[0065] IX. In the description of the present application, the words "exemplary", "for example", "e.g.", "for instance" and the like are used to mean an example, instance or illustration. Any embodiment or design solution described in the present application as "exemplary" should not be construed as preferred or advantageous over other embodiments or design solutions. Rather, use of the word "exemplary" is intended to present concepts in a concrete manner. In the embodiments of the present application, "of", "corresponding" and "corresponding" are sometimes mixed. It should be pointed out that when there is no emphasis on their differences, the meanings expressed are consistent.

[0066] X. The embodiments of the present application will be presented around a system comprising a plurality of devices, components, modules, etc. It should be understood that the system can comprise other devices, components, modules, etc. not mentioned, or only part of the devices, components, or modules mentioned in the embodiments. Alternatively, "component" and "part" in the present application can be replaced with each other.

[0067] XI. In the description of the present application, "storage" or "save" refers to storage in one or more memories. The one or more memories can be separately provided or integrated in the processor or communication device. The one or more memories can be partially separately provided and partially integrated in the processor or communication device. The type of memory can be any form of storage medium, which is not limited.

[0068] XII. The network architecture and service scenarios described in the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that as the network architecture evolves and new service scenarios appear, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0069] Thirteen, the technical solutions of the embodiments of the present application can be applied to various communication systems, for example, integrated sensing and communication (ISAC), universal mobile telecommunications system (UMTS), wireless local area network (WLAN), extended reality (XR) communication system, short-range wireless communication system (such as sidelink, wireless fidelity (Wi-Fi), Bluetooth, etc.), wired network, vehicle to everything (V2X) communication system, device-to-device (D2D) communication system, Internet of Vehicles communication system, 4th generation (4G) mobile communication system (such as long term evolution (LTE) system), LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), worldwide interoperability for microwave access (WiMAX) communication system, 5th generation (5G) mobile communication system (such as new radio (NR) system), future communication system (such as 6th generation (6G) mobile communication system), or other similar communication systems, etc., without limitation.

[0070] FIG. 1 shows a schematic diagram of a communication system to which the present application is applicable, and the method of the present application can be applied to the communication system shown in FIG. 1. As shown in FIG. 1, the communication system 1000 includes a radio access network (RAN) 100 and a core network (CN) 200. The RAN 100 includes at least one RAN node (e.g., 110a and 110b in FIG. 1, collectively referred to as 110) and at least one terminal device (e.g., 120a-120j in FIG. 1, collectively referred to as 120). Other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in FIG. 1), etc., can also be included in the RAN 100. The terminal devices 120 are connected to the RAN nodes 110 in a wireless manner. The RAN nodes 110 are connected to the core network 200 in a wireless or wired manner. The core network devices in the core network 200 and the RAN nodes 110 in the RAN 100 can be different physical devices respectively, or can be the same physical device integrated with the logical functions of the core network and the radio access network. Optionally, the communication system 1000 further includes an Internet 300.

[0071] The RAN 100 can be a 3rd generation partnership project (3GPP)-related cellular system, e.g., a 4G, 5G mobile communication system, or a future-oriented communication system (e.g., a 6G mobile communication system). The RAN 100 can also be an open radio access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system. The RAN 100 can also be a communication system that combines two or more of the above systems.

[0072] The RAN node 110, which can also be referred to as an access network device, a RAN entity, or an access node, etc., forms part of the communication system, and is configured to facilitate the wireless access by terminal devices. The RAN nodes 110 in the communication system 1000 can be the same type of nodes or different types of nodes. In some scenarios, the roles of a RAN node 110 and a terminal device 120 are relative, e.g., a drone or a helicopter 120i in Figure 1 can be configured to move like a mobile base station, and for a terminal device 120j accessing the RAN 100 via the drone 120i, the drone 120i is a base station; but for a base station 110a, the drone 120i is a terminal device. The RAN nodes 110 and the terminal devices 120 are sometimes referred to as communication apparatuses, e.g., the network elements 110a and 110b in Figure 1 can be understood as communication apparatuses with base station functionalities, and the network elements 120a-120j can be understood as communication apparatuses with terminal device functionalities

[0073] In a possible scenario, the RAN node can be a base station, an evolved Node B (eNodeB), an access point (AP), a transmission reception point (TRP), a next generation Node B (gNB), a base station in a future communication network, or an access node in a WiFi system, etc. The RAN node can be a macro base station (e.g., 110a in Figure 1), a micro base station or an indoor station (e.g., 110b in Figure 1), a relay node or a donor node, or a wireless controller in a CRAN scenario, or a satellite, a drone, or a device assuming base station functionalities in device-to-device (D2D) and / or machine-to-machine (M2M) transmission, etc. Optionally, the RAN node can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, an access network device in vehicle to everything (V2X) technology can be a road side unit (RSU). All or part of the functionalities of the RAN node in the present application can also be implemented by software functions running on hardware, or by virtualized functions instantiated on a platform (e.g., a cloud platform). The RAN node in the present application can also be a logical node, a logical module, or software capable of implementing all or part of the functionalities of the RAN node.

[0074] In another possible scenario, a terminal device is assisted by multiple RAN nodes to implement wireless access, and different RAN nodes respectively implement part of functions of a base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately configured, or can also be included in the same network element, for example, in a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, for example, included in a remote radio unit (RRU), an active antenna processing unit (AAU), or a remote radio head (RRH).

[0075] The CU and the DU can be configured according to protocol layer functions of a wireless network that they implement. For example, the CU is configured to implement functions of a packet data convergence protocol (PDCP) layer and above protocol layers (for example, a radio resource control (RRC) layer and / or a service data adaption protocol (SDAP) layer, etc.); and the DU is configured to implement functions of one or more of a radio link control (RLC) layer, a media access control (MAC) layer, or a physical (PHY) layer below the PDCP layer. For another example, the CU is configured to implement functions of the PDCP layer and above protocol layers (for example, the RRC layer and / or the SDAP layer), and the DU is configured to implement functions of one or more of the RLC layer, the MAC layer, or the PHY layer below the PDCP layer.

[0076] The above configuration of the CU and the DU is merely an example, and the CU and the DU can be configured to have functions as needed. For example, the CU or the DU can be configured to have functions of more protocol layers, or the CU or the DU can be configured to have partial processing functions of the protocol layers. For example, partial functions of the RLC layer and functions of protocol layers above the RLC layer are arranged in the CU, and the remaining functions of the RLC layer and functions of protocol layers below the RLC layer are arranged in the DU. For another example, the functions of the CU or the DU can be divided according to a service type or other system requirements, for example, according to a delay requirement. For example, functions that require a shorter delay requirement in processing time are arranged in the DU, and functions that do not require the delay requirement are arranged in the CU.

[0077] The DU and the RU can cooperate to jointly implement the functions of the PHY layer. One DU can be connected to one or more RUs. The functions of the DU and the RU can be configured in various ways according to design. For example, the DU is configured to implement baseband functions, and the RU is configured to implement intermediate radio frequency functions. For another example, the DU is configured to implement high-layer functions in the PHY layer, and the RU is configured to implement low-layer functions in the PHY layer or to implement the low-layer functions and radio frequency functions. The high-layer functions in the PHY layer can include a part of the functions of the PHY layer that are closer to the MAC layer, and the low-layer functions in the PHY layer can include another part of the functions of the PHY layer that are closer to the intermediate radio frequency side.

[0078] The CU (or the CU-CP and the CU-UP), the DU, or the RU can also have different names in different systems, but those skilled in the art can understand their meanings. For example, in an ORAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, the CU-CP, the CU-UP, the DU, and the RU are taken as examples for description in this application. Any of the CU (or the CU-CP, the CU-UP), the DU, and the RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0079] The terminal device can also be referred to as a terminal, a user equipment (UE), a mobile station, a mobile terminal device, etc. The terminal device can be widely applied to various scenarios, such as D2D, vehicle to everything (V2X) communication, machine-type communication (MTC), internet of things (IOT), virtual reality, augmented reality, industrial control, automatic driving, remote medical treatment, smart power grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal device can be a mobile phone, a tablet computer, a computer with wireless transceiving function, a wearable device, a vehicle, a drone, a helicopter, an airplane, a ship, a robot, a mechanical arm, a smart home device, etc.

[0080] At present, some terminal devices are exemplified as: a mobile phone, a satellite mobile terminal device, a cellular phone, a smart phone, a tablet computer, a notebook computer, a palm computer, a mobile internet device (MID), a wearable device (for example, a smart watch, a smart bracelet, a pedometer, smart glasses, etc.), a vehicle-mounted device (for example, a car, a bicycle, an electric vehicle, an airplane, a ship, a train, a high-speed rail, etc.), a satellite terminal device, a virtual reality (VR) device, an augmented reality (AR) device, a smart point of sale (POS) machine, a customer-premises equipment (CPE), a wireless terminal device in industrial control, a wireless terminal device in self driving, a wireless terminal device in remote medical surgery, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, a wireless terminal device in a smart home (for example, a refrigerator, a television, an air conditioner, an electric meter, etc.), a smart robot, a mechanical arm, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with a wireless communication function, a computing device or other processing device connected to a wireless modem, a flight device (for example, a smart robot, a hot air balloon, a drone, an airplane), a terminal device in a 5G network, or a terminal device in a future evolved public land mobile network (PLMN), etc., and embodiments of the present application do not limit the device form of the terminal device.

[0081] The RAN nodes 110 and the terminal devices 120 can be fixed positions or movable. The RAN nodes 110 and the terminal devices 120 can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on water; and can also be deployed on airplanes, airships, and artificial satellites in the air. The embodiments of the present application do not limit the application scenarios of the RAN nodes 110 and the terminal devices 120. The RAN nodes 110 and the terminal devices 120 can be deployed in the same scenario or different scenarios, for example, the RAN nodes 110 and the terminal devices 120 are deployed on land at the same time; or the RAN nodes 110 are deployed on land and the terminal devices 120 are deployed on water, and the like, which are not listed one by one.

[0082] The RAN nodes 110 and the terminal devices 120 can communicate through licensed frequency spectrum, through unlicensed frequency spectrum, or through both licensed frequency spectrum and unlicensed frequency spectrum; for example, the RAN nodes 110 and the terminal devices 120 can communicate through frequency spectrum below 6 gigahertz (GHz), can communicate through frequency spectrum above 6 GHz, and can also communicate through both frequency spectrum below 6 GHz and frequency spectrum above 6 GHz. The embodiments of the present application do not limit the frequency spectrum resources used for wireless communication.

[0083] It can be understood that the RAN node is used to help the terminal device to implement wireless access, and it can also have other different descriptions, for example, RAN entity, ORAN device, access node, access network device, and the like; in the subsequent description of the embodiments of the present application, if not specially specified, the node or device that helps the terminal device to implement wireless access is referred to as “access network device” for description.

[0084] It can be understood that the terminal device and the access network device can be referred to as communication apparatuses, for example, the terminal device can be understood as a communication apparatus with terminal device function, and the access network device can be understood as a communication apparatus with access network device function. In the method of the present application, the function of the access network device can also be executed by a module, unit or component (such as a chip) in the access network device, or by a control subsystem containing the function of the access network device. The control subsystem containing the function of the access network device herein can be a control center in the above-mentioned application scenarios such as smart grid, industrial control, intelligent transportation, and smart city. The function of the terminal device can also be executed by a module, unit or component (such as a chip or modem) in the terminal device, or by an apparatus containing the function of the terminal device.

[0085] Figure 2 shows a schematic diagram of an ORAN system to which the method of the present application is applicable. The method of the present application can be applied in the ORAN system shown in Figure 2. The ORAN system can comprise other components than those shown in Figure 2. As shown in Figure 2, the ORAN system comprises a core network device, an access network device and a terminal device. The access network device communicates with the core network device through a backhaul and communicates with the terminal device through an air interface.

[0086] Specifically, the access network device comprises a BBU and a RU. The BBU communicates with the core network device through a backhaul, and the RU communicates with the terminal device through an air interface. The BBU communicates with at least one RU through a fronthaul. The BBU and the RU can be co-located or not co-located. The BBU comprises at least one CU and at least one DU, which can communicate through at least one midhaul.

[0087] The DU and the RU have an interface therebetween. Depending on the functions possessed by the DU and the RU and / or the splitting manner, the interface between the DU and the RU can be a common public radio interface (CPRI) or an enhanced common public radio interface (eCPRI).

[0088] Figure 3 shows a schematic diagram of a network element function division and a protocol layer structure of an O-RAN device to which the method of the present application is applicable. The access network device in the method of the present application can be alternatively referred to as an O-RAN device. The O-RAN device can adopt the network element function division and the protocol layer structure shown in Figure 3.

[0089] The O-RAN device can be understood as an access network device adopting the O-RAN architecture, which is used to realize wireless access of a terminal device. It can be understood that the communication between the O-RAN device and the terminal device follows a certain protocol layer structure. The protocol layer structure can include a control plane protocol layer structure and a user plane protocol layer structure. For example, the control plane protocol layer structure can include the functions of protocol layers such as a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a media access control (MAC) layer, and a physical layer. For example, the user plane protocol layer structure can include the functions of protocol layers such as a PDCP layer, an RLC layer, a MAC layer, and a physical layer, and in a possible implementation, a service data adaptation protocol (SDAP) layer can be further included above the PDCP layer.

[0090] As shown in FIG. 3, the O-RAN device includes logical nodes such as a CU, a DU, and an RU. The CU can be connected to a core network through an interface, for example, the interface can be referred to as an E2 interface. Alternatively, the CU can have part of the functions of the core network. The CU can control at least one DU, and the CU can be connected to the DU through an interface, for example, the interface can be referred to as an F1 interface. Further, a control panel (CP) interface can be referred to as an F1-C, and a user panel (UP) interface can be referred to as an F1-U. The DU can control at least one RU, and the DU can be connected to the RU through an interface, for example, the interface can be a fronthaul interface.

[0091] 1. CU

[0092] The CU can be a logical node that carries the RRC layer, the SDAP layer, the PDCP layer, and other control functions. That is, the CU can implement the functions of the RRC layer, the SDAP layer, the PDCP layer, and certain control functions.

[0093] Further, the CU can be split into a CU-CP and a CU-UP. Referring to FIG. 3, the CU-CP is a logical node that carries a control plane part of a PDCP (PDCP-C) layer and a RRC layer, and is used to implement a control plane function of the CU. The CU-CP can interact with a network element in a core network for implementing a control plane function. The network element in the core network for implementing the control plane function can be an access and mobility function network element, for example, an access and mobility management function (AMF) in a 5G communication system. Continuing to refer to FIG. 3, the CU-UP is a logical node that carries a user plane part of a PDCP (PDCP-U) layer and an SDAP layer, and is used to implement a user plane function of the CU. The CU-UP can interact with a network element in a core network for implementing a user plane function. The network element in the core network for implementing the user plane function, for example, a user plane function (UPF) in a 5G communication system.

[0094] 2、DU

[0095] The DU can be a logical node that carries an RLC layer, a MAC layer, a higher physical (Higher PHY) layer, and other functions. For example, the higher physical layer can include partial processing functions of the PHY layer, such as forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, and the like. That is, the DU can implement the functions of the RLC layer, the MAC layer, the higher physical layer, and other functions.

[0096] It can be understood that the above configuration of the CU and the DU is merely an example, and the CU and the DU can be configured to have functions as needed. For example, the CU or the DU can be configured to have functions of more protocol layers, or the CU or the DU can be configured to have partial processing functions of the protocol layers. For example, partial functions of the RLC layer and functions of protocol layers above the RLC layer can be provided in the CU, and the remaining functions of the RLC layer and functions of protocol layers below the RLC layer can be provided in the DU. For another example, the functions of the CU or the DU can be divided according to a service type or other system requirements, for example, according to a delay requirement. Functions that require a processing time to meet a relatively low delay requirement can be provided in the DU, and functions that do not require the processing time to meet the delay requirement can be provided in the CU.

[0097] 3、RU

[0098] The RU can be a logical node that carries lower physical layer (Lower PHY) and radio frequency (RF) chain processing. For example, the lower physical layer includes partial processing functions of the physical layer, such as fast Fourier transform (FFT), inverse fast Fourier transformation (IFFT), digital beamforming, and filtering, etc. That is, the RU can implement the functions of the physical layer and the radio frequency.

[0099] In one possible implementation, the RU can be a 3GPP transmission reception point (TRP) or a remote radio head (RRH) or other similar functional entity. The RU communicates with one or more terminal devices through a wireless link.

[0100] The DU and the RU can be co-located or not co-located, without limitation. Referring to FIG. 3, the DU and the RU can include an O-RAN control user and synchronization (CUS-Plane) plane and an O-RAN management plane (M-Plane). The O-RAN CUS plane can be referred to as the CUS plane, and the O-RAN management plane can be referred to as the management plane. Further, the CUS plane can be split into a control plane (C-Plane) and a user plane (U-Plane). Optionally, the control plane refers to a real-time control plane between the DU and the RU. The management plane refers to a non-real-time management operation between the DU and the RU.

[0101] Referring to FIG. 3, the DU and the RU exchange information of the control plane and information of the user plane through a lower-layer split CUS-Plane (LLS-CUS) interface via a fronthaul link. Further, the LLS-CUS interface can include an LLS-C interface corresponding to the control plane and an LLS-U interface corresponding to the user plane. The DU and the RU exchange information of the management plane through an LLS-M interface of the fronthaul link. Referring to FIG. 3, the LLS-M interface can also be connected to an external management system.

[0102] It can be understood that the DU and the RU can cooperate to jointly implement the functions of the physical layer. One DU can be connected with one or more RUs. The functions of the DU and the RU can be configured in multiple ways according to design. For example, the DU is configured to implement baseband functions, and the RU is configured to implement medium radio frequency functions. For another example, the DU is configured to implement high-layer functions in the physical layer, and the RU is configured to implement low-layer functions in the physical layer or implement the low-layer functions and radio frequency functions. The high-layer functions in the physical layer can include a part of functions of the physical layer that are closer to the MAC layer, and the low-layer functions in the physical layer can include another part of functions of the physical layer that are closer to the medium radio frequency side.

[0103] For the convenience of description, some communication terms or terminologies involved in the present application are explained and described. It can be understood that the explanation and description are used to understand the method of the present application, and do not limit the present application.

[0104] 1. Two-step random access (2-Step Random Access)

[0105] The two-step random access is a process for a terminal device (such as a UE) to establish an initial connection with an access network device (such as a gNB). Compared with the four-step random access, the two-step random access reduces the process, reduces the signaling overhead and delay, and is suitable for scenarios with high latency requirements. As shown in FIG. 4, a flowchart of the two-step random access is provided, including:

[0106] Step 410: The terminal device sends a message A. Correspondingly, the access network device receives the message A.

[0107] The message A includes two parts: a random access preamble and a physical uplink shared channel (PUSCH). The random access preamble is sent on a physical random access channel (PRACH), and the random access preamble can also be referred to as a PRACH preamble. The PUSCH includes a demodulation reference signal (DMRS) and uplink data. The DMRS is used to demodulate the uplink data carried in the PUSCH. Optionally, the uplink data includes an identity of the terminal device (such as a cell-radio network temporary identifier (C-RNTI) or other temporary identifier) and other necessary information, such as a buffer status report and a scheduling request.

[0108] For example, the terminal device can select one preamble from a preamble set (e.g., the preamble set contains 64 preambles) and transmit. Alternatively, the preamble set is refined into two groups, which are group A and group B. In group A or group B, one preamble is selected and transmitted. For example, the terminal device can determine to select a preamble in group A or group B according to the size of the PUSCH to be transmitted and / or the path loss, etc. For example, group B is suitable for the scenario where the PUSCH is large and the path loss is small, and group A is suitable for other scenarios that are not suitable for group B. The terminal device can measure the path loss size of the PUSCH through a parameter carried in the system information block 1 (SIB1) sent by the access network device.

[0109] The terminal device transmits a preamble on a random access occasion (RO, RACH). For example, the terminal device can determine the RO for transmitting the preamble according to the correspondence between the SSB and the RO. For example, the terminal device can measure the SSB to determine the SSB that meets the condition. For example, the SSB that meets the condition can be the SSB with the highest received signal strength, or the SSB with the highest received signal power, or the SSB with the highest received signal quality, etc. The terminal device transmits the preamble on the RO corresponding to the SSB that meets the condition. It should be noted that the full name of SSB in Chinese and English is synchronization signal / physical broadcast channel block (SSB). One SSB can include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The PSS and SSS can be used for terminal device synchronization, and the PBCH can be used to carry the master information block (MIB), etc.

[0110] For example, in a contention-based access scenario, the access network device does not know the preamble actually used by the terminal device. The access network device can traverse all preambles in the preamble set for cross-correlation detection, and the preamble with the largest cross-correlation value can be considered as the preamble sent by the terminal device. Further, the access network device can determine the corresponding parameters according to the detected preamble. For example, the preamble is a sequence, and the access network device can determine the starting position of the preamble received by the access network device by performing signal processing on the received preamble sequence, and further estimate the transmission delay between the terminal device and the access network device, and further determine the time advanced (TA) according to the transmission delay between the terminal device and the access network device. Alternatively, the access network device notifies the terminal device of the TA through message B, and the terminal can adjust the uplink timing according to the TA.

[0111] Step 420: In response to message A, the access network device sends message B. Correspondingly, the terminal device receives message B.

[0112] Message B contains a contention resolution identifier for resolving conflicts when multiple terminal devices access simultaneously. For example, in a scenario where multiple terminal devices access simultaneously, the multiple terminal devices cause contention, and the contention resolution identifier contained in message B can be the identity of the terminal device that successfully accesses. Alternatively, message B further contains other necessary information, such as uplink authorization: allocating resources to the terminal to continue communication. Timing advance command: adjusting the transmission timing of the terminal device.

[0113] When the terminal device receives message B, it can obtain the contention resolution identifier in message B. It is judged whether the contention resolution identifier is the same as the identity of the terminal device; if they are the same, the terminal device considers that the contention resolution / random access is successful. Further, it can continue communication according to the indication of the access network device. For example, there can be a scenario where multiple terminal devices select the same RO and send the same preamble. At this time, the above multiple terminal devices will cause contention. The access network device can only detect one preamble with the strongest energy on the above RO, and the access network device cannot determine that there are multiple terminal devices simultaneously applying for random access in the current scenario. This scenario is a scenario where multiple terminal devices randomly access collision.

[0114] It can be understood that in the method of four-step random access: the terminal device sends message 1 to the access network device, and the message 1 contains a preamble. In response to the message 1, the access network device sends the message 2 to the terminal device, and the message 2 can also be called a random access response (RAR). The terminal device sends message 3 to the access network device, and the message 3 contains the identity of the terminal device. The access network device sends message 4 to the terminal device, and the message 4 can be called a contention resolution message, and the message 4 contains a contention resolution identity. In one understanding, the message A in the above two-step random access corresponds to the message 1 and the message 3 in the four-step random access process. The message B corresponds to the message 2 and the message 4 in the four-step random access process.

[0115] Two-step random access has the following advantages: reducing signaling overhead: simplifying the 4-step process to 2 steps, reducing the number of message interactions. Reduce access delay: suitable for low-latency high-reliability communication (ultra-reliable low-latency communication, URLLC) and other latency-sensitive scenarios. Improve efficiency: suitable for small data packet transmission or frequent access scenarios. Two-step random access is applicable but not limited to the following applications or scenarios: small data packet transmission (such as IoT devices), high-latency applications (such as industrial automation, Internet of Vehicles), high-frequency access scenarios, etc. In general, two-step random access simplifies the process, reduces signaling overhead and access delay, and is an important mechanism for improving efficiency and performance in 5G NR.

[0116] 2、First reference signal

[0117] The first reference signal is a reference signal introduced (or newly added) by the method of the present application. The first reference signal is used to demodulate the first uplink data carried by the first PUSCH. For example, the first reference signal and the second reference signal can be jointly used to demodulate the first uplink data.

[0118] Optionally, since the first reference signal is used to demodulate the first uplink data, it is necessary to ensure that the channel characteristics experienced by the first reference signal and the first uplink data are consistent or similar. In the present application, by limiting the characteristics between the first reference signal and the second reference signal, it can be ensured that the channel characteristics experienced by the first reference signal and the first uplink data are similar, or described as, so that the first reference signal can be used to demodulate the first uplink data.

[0119] 3、Second reference signal

[0120] The second reference signal is carried in the first PUSCH. The second reference signal is used to demodulate the first uplink data carried in the PUSCH. For example, the first PUSCH carries both a second reference signal and the first uplink data, and the second reference signal is used to demodulate the first uplink data. In this application, the difference is that a first reference signal is newly introduced (or added), and both the first and second reference signals are used (or jointly) to demodulate the first uplink data. The name of the second reference signal is not limited; for example, the second reference signal can be a demodulation reference signal (DMRS).

[0121] The second reference signal (DMRS) experiences the same or similar channel characteristics as the first uplink data. The receiving end (access network equipment) can determine the equivalent channel based on the DMRS and demodulate the first uplink data based on the equivalent channel. The type of the second reference signal (DMRS) in this application is not limited; for example, the second reference signal can be type 1 or type 2. The number of symbols occupied by the DMRS is not limited; for example, the DMRS can occupy one symbol, called a single-symbol DMRS. Alternatively, the DMRS can occupy multiple symbols, called a multi-symbol DMRS. Optionally, the bandwidth or frequency domain resources occupied by the second reference signal (DMRS) and the first uplink data can be the same.

[0122] 4. Non-connected state

[0123] Unless otherwise specified, the terminal devices involved in this application are all in the following states: disconnected state. The disconnected state includes the idle state and the inactive state. The idle state refers to the state in which the terminal device has completed its camping in the cell but has not performed random access. Typically, the terminal device enters the idle state when it powers on or releases RRC. The inactive state is the state between the connected state and the idle state. In the inactive state, the user plane of the air interface between the terminal device and the access network is suspended, while the user plane and control plane bearers between the access network and the core network are maintained. When the terminal device is paged or initiates a service request, it can activate the user plane bearers of the air interface, reusing the existing user plane and control plane bearers between the access network and the core network. Compared to the idle state, the terminal device in the inactive state retains system messages and the terminal device's context, allowing for rapid data transmission after the air interface connection is restored. In some descriptions, the disconnected state may be referred to as the RRC disconnected state, and the idle state and inactive state may be referred to as the RRC idle state and RRC inactive state, respectively.

[0124] 5. Time Division Multiplexing, Frequency Division Multiplexing, and Code Division Multiplexing

[0125] The English name of time division multiplexing is (Time Division Multiplexing, TDM), which is a kind of multiplexing technology. Time division multiplexing divides time into multiple time domain resources, so that multiple signals are transmitted alternately in the same channel, and each signal occupies different time domain resources. In this application, the first reference signal and the second reference signal occupy different time domain resources. Further, the first reference signal and the second reference signal occupy the same frequency domain resource and / or code resource, at this time, the first reference signal and the second reference signal can be called time division multiplexing.

[0126] The English name of frequency division multiplexing is (Frequency Division Multiplexing, FDM), which is a kind of multiplexing technology. Frequency division multiplexing divides the frequency band into multiple non-overlapping frequency domain resources, so that multiple signals are transmitted in parallel on the same channel. In this application, the first reference signal and the second reference signal can occupy different frequency domain resources. Further, the first reference signal and the second reference signal occupy the same time domain resource and / or code resource, at this time, the first reference signal and the second reference signal can be called frequency division multiplexing.

[0127] The English name of code division multiplexing is (Code Division Multiplexing, CDM), which is a kind of multiplexing technology. Code division multiplexing is to distinguish different terminal devices by different code resources, which allows multiple terminal devices to share the same transmission resource (such as time domain resource or code domain resource). As in this application, the first reference signal corresponds to the first sequence (such as the first reference signal is generated according to the first sequence), and the second reference signal corresponds to the second sequence (such as the second reference signal is generated according to the second sequence). The first sequence and the second sequence are different sequences, such as the first sequence and the second sequence can be orthogonal sequences.

[0128] 6、Wireless frame, subframe, slot and symbol

[0129] One radio frame can contain one or more subframes, and one subframe can contain one or more slots. For example, 1 radio frame has a length of 10 ms. 1 radio frame can contain 10 subframes, and each subframe has a length of 1 ms. The length of a slot can be different under different sub-carrier spacing (SCS). For example, when the sub-carrier spacing (SCS) is 15 kHz, one slot is 1 ms, and one subframe contains 1 slot. When the SCS is 30 kHz, the length of one subframe is 0.5 ms, and one subframe contains 2 slots. One slot contains one or more symbols. For example, one slot contains 14 symbols under normal cyclic prefix (CP), and one slot contains 12 symbols under extended CP. The symbol can be an orthogonal frequency division multiplexing (OFDM) symbol or other types of symbols, without limitation.

[0130] 7. Interference covariance matrix

[0131] The interference covariance matrix describes the covariance relationship between multiple interference sources or interference components, reflecting the spatial or temporal correlation. For example, in a wireless communication system, there can be multiple interference sources, and the signals transmitted by these interference sources are correlated. In this case, the interference covariance matrix is needed to describe the covariance relationship between these interference signals. In this way, the receiving end may need to estimate the interference covariance matrix when performing signal processing, such as beamforming or interference suppression, so as to more effectively eliminate interference.

[0132] In the scenario of two-step random access, a method is currently proposed: the access network device demodulates the uplink data contained in the PUSCH based on the preamble and the DMRS. For example, the access network device performs joint channel estimation based on the preamble and the DMRS, and demodulates the uplink data contained in the PUSCH based on the result of the channel estimation. Since the time domain interval of the preamble and the DMRS is large, it can cause the phase of the preamble and the uplink data to be discontinuous, resulting in the inability to jointly demodulate the uplink data contained in the PUSCH based on the preamble and the DMRS, thereby causing the demodulation performance of the PUSCH to be limited.

[0133] For example, consider the commonly used Time Division Duplex (TDD) frame structure: DDDSU. Here, D represents a downlink subframe used for downlink transmission. S represents a special subframe used for both uplink and downlink transmission. An S subframe can be considered to contain both downlink time slots for downlink transmission and uplink time slots for uplink transmission, with a guard interval (gap) between them. U represents an uplink subframe used for uplink transmission.

[0134] For terminal equipment or access network equipment, the TDD frame structure DDDSU described above can be extended to determine the subframes included in each TDD cycle. For example, as shown in Figure 5, the subframe included in the first TDD cycle is DDDSU. The subframe included in the second TDD cycle is also DDDSU.

[0135] As specified in the protocol, PRACH and PUSCH are transmitted on different uplink subframes U. As shown in Figure 5, the terminal device transmits PRACH (carrying a preamble) on the uplink subframe U of the first TDD cycle, and transmits PUSCH (carrying DMRS and uplink data) on the uplink subframe U of the second TDD cycle. It can be seen that the preamble and PUSCH are separated by three downlink subframes D and one special subframe S. The large time-domain interval between the preamble and DMRS may lead to phase discontinuity between them. For example, the terminal device includes a transmitter containing power amplifiers (PAs), which amplify the signal transmitted by the terminal device. The phase of the PA and other components in the transmitter may jump. The large time-domain interval between the preamble and DMRS may cause phase discontinuity between them. For instance, in the uplink subframe U of the first TDD cycle, the phase of the PA in the transmitter included in the terminal device is phase X1, while the phase of the preamble transmitted by the terminal device is phase X2. Subsequently, the phase of the PA (Power Amplifier) ​​of the transmitter included in the terminal device changes to Y1. In the uplink subframe U of the second TDD cycle, the phase of the PUSCH transmitted by the terminal device is Y2. Of course, the phase of the DMRS carried by the PUSCH can also be considered as Y2. Since phase X2 and phase Y2 are discontinuous, the access network equipment cannot perform channel estimation in conjunction with the preamble and DMRS, and therefore cannot demodulate the uplink data in conjunction with the preamble and DMRS, thus limiting the demodulation performance of the PUSCH.

[0136] To address the aforementioned problems, this application provides a method and apparatus. In this method: a new reference signal (referred to as a first reference signal) is added to message A. The time-domain interval between the first reference signal and the second reference signal (DMRS) is smaller than the time-domain interval between the second reference signal (DMRS) and the first random access preamble. The first reference signal is transmitted between the first random access preamble and the second reference signal (DMRS). This brings the time-domain positions of the first and second reference signals closer. Therefore, within the time-domain interval between the first and second reference signals, the probability of phase transitions occurring in devices such as the PA of the transmitter included in the terminal equipment will decrease, and the probability of phase continuity between the first and second reference signals will be higher than the probability of phase continuity between the first random access preamble and the second reference signal. This increases the probability of successful uplink data demodulation and improves the demodulation performance of the PUSCH.

[0137] It is understood that in the following description of the method, the executing entity can be a first device and a second device. The first device can be a terminal device, a component within the terminal device (e.g., a communication module, processor, circuit, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. For example, the first device can be a communication module within the terminal device, or a circuit, chip, or chip system responsible for communication functions within the terminal device, such as a modem chip (also known as a baseband chip), or a system-on-a-chip (SoC) chip or system-in-package (SIP) chip containing a modem core. The second device can be an access network device, or a component within the access network device (e.g., a communication module, processor, circuit, chip, or chip system), or a logic module / node or software capable of implementing all or part of the access network device's functions (e.g., a CU, DU, or RU). For ease of understanding and description, the following description uses the example of a terminal device as the first device and an access network device as the second device to illustrate the method of this application.

[0138] Furthermore, in the description of this application, "first PRACH" and "first random access preamble" are interchangeable. It is understood that the first random access preamble is carried in the first PRACH, or described as the first PRACH carrying the first random access preamble. "First PUSCH" and "second reference signal and first uplink data" are interchangeable. It is understood that the second reference signal and first uplink data are carried in the first PUSCH, or described as the first PUSCH carrying the second reference signal and first uplink data. As in the description of this application, the following four descriptions can be considered equivalent, and the following four descriptions are interchangeable. And in the method shown in Figure 6 below, the third description is mainly used as an example to explain message A:

[0139] 1. Message A contains a first PRACH, a first reference signal, and a first PUSCH. The first PRACH carries a first random access preamble, and the first PUSCH carries a second reference signal and first uplink data.

[0140] 2. Message A contains a first random access preamble, a first reference signal, a second reference signal, and first uplink data. The first random access preamble is carried on the first PRACH, and the second reference signal and the first uplink data are carried on the first PUSCH.

[0141] 3. Message A contains a first random access preamble, a first reference signal, and a first PUSCH. The first PUSCH carries a second reference signal and first uplink data.

[0142] 4. Message A contains a first PRACH, a first reference signal, a second reference signal, and first uplink data. The first PRACH carries a first random access preamble, and the second reference signal and the first uplink data are carried on the first PUSCH.

[0143] Furthermore, in the description of this application, the terms "bearing," "containing," and "carrying" are interchangeable. For example, "the first PUSCH carries the first uplink data and the second reference signal" can be replaced with: "the first PUSCH contains the first uplink data and the second reference signal," or "the first PUSCH carries the first uplink data and the second reference signal."

[0144] Figure 6 provides a flowchart illustrating a communication method. The method shown in Figure 6 can be applied to a two-step random access process. Message A and message B in the method shown in Figure 6 can be messages A and B in the two-step random access process. For details on two-step random access, please refer to the explanation in Communication Terminology or Term 1 above. This method includes:

[0145] Step 610: The terminal device sends message A (message A, MsgA).

[0146] Accordingly, the access network device receives message A.

[0147] In one description, message A includes a first random access preamble, a first reference signal, and a first PUSCH, whereby the first PUSCH carries first uplink data and a second reference signal. The following is a detailed description of message A:

[0148] 1. First random access preamble

[0149] The English name for the first random access preamble is preamble. There are no restrictions on the name of the first random access preamble; it can also be named preamble, preamble code, preamble of PRACH bearer, PRACH preamble, or random access request, etc.

[0150] The process by which the terminal device determines the first random access preamble is not restricted. For example, the terminal device can select a preamble from the preamble set (the selected preamble can be considered as the first random access preamble). For example, the preamble set contains 64 preambles. The terminal device selects one preamble from the 64 preambles as the first random access preamble. Alternatively, the terminal device can select a preamble from group A or group B (the selected preamble can be considered as the first random access preamble). For example, the preamble set can be further subdivided into group A and group B. Group A contains 32 preambles, and group B contains 32 preambles. The terminal device can select one preamble from group A or group B as the first random access preamble. Furthermore, the terminal device can specifically determine whether to select a preamble from group A or group B based on the data volume of the first PUSCH and / or path loss. For example, group B is suitable for scenarios with a large data volume and low path loss in the first PUSCH, while group A is suitable for other scenarios besides group B. Optionally, the terminal device may determine the path size of the first PUSCH based on system messages (such as SIB1) sent by the access network device.

[0151] It is understandable that the terminal device transmits the first random access preamble on the RO corresponding to the PRACH. The RO can be understood as the time-frequency domain resource for transmitting the first random access preamble. There are no restrictions on the method by which the terminal device determines the RO. For example, the terminal device can determine the RO based on the received synchronization signal (such as the SSB). Specifically, the terminal device measures the synchronization signal (such as the SSB) to determine a synchronization signal that meets certain conditions. For example, a synchronization signal that meets certain conditions could be the synchronization signal with the highest received signal strength, the synchronization signal with the highest received signal power, or the synchronization signal with the highest received signal quality, etc. The terminal device determines the RO corresponding to the synchronization signal that meets the conditions based on the mapping relationship between the synchronization signal and the RO; the terminal device then uses the corresponding RO to transmit the first random access preamble. The mapping relationship between the synchronization signal and the RO can be predefined or preconfigured, and is not restricted.

[0152] 2. First PUSCH.

[0153] The first PUSCH carries the first uplink data and the second reference signal. The second reference signal is a demodulation reference signal used to demodulate the first uplink data. The name of the second reference signal is not limited; for example, it could be DMRS. The content of the first uplink data is not limited. For example, the first uplink data may include: the terminal device's identification (e.g., the terminal device's C-RNTI) and other necessary information, such as buffer status reports and scheduling requests.

[0154] For example, in one interpretation, message A is equivalent to messages 1 and 3 in the four-step random access process. The first random access preamble contained in message A is equivalent to message 1, and the first PUSCH contained in message A is equivalent to message 3. For details regarding the first random access preamble, please refer to the explanation of message 1 in the four-step random access process. For details regarding the second reference signal (such as DMRS) and the first uplink data carried by the first PUSCH, please refer to the explanation of message 3 in the four-step random access process.

[0155] Understandably, the terminal device can transmit the first PUSCH on the corresponding PUSCH occasion (PO). PO can be understood as the time-frequency domain resource for transmitting the first PUSCH. For example, the terminal device can determine the PO based on the aforementioned first random access preamble and / or RO, etc. The terminal device can use the corresponding DMRS sequence to transmit the second reference signal on the corresponding DMRS port. For example, the terminal device can determine the corresponding DMRS sequence and DMRS port based on the aforementioned first random access preamble and / or RO, etc.

[0156] For example, there is a mapping relationship between (preamble and / or RO) and PUSCH radio unit (PRU). A PRU includes: PO, DMRS port, and DMRS sequence. That is, there is a mapping relationship between (preamble and / or RO) and (PO, DMRS port, and DMRS sequence). After determining the first random access preamble and the corresponding RO, the terminal device can query the stored mapping relationship for (the first random access preamble and / or the corresponding RO) and its corresponding PRU (such as the first PRU). The terminal device transmits the first PUSCH on the PO included in the first PRU. More specifically, the terminal device can generate a second reference signal (DMRS) based on the DMRS sequence included in the first PRU. The second reference signal (DMRS) is transmitted on the DMRS port included in the first PRU.

[0157] Optionally, the mapping relationship between (preamble and / or RO) and PRU can be predefined or preconfigured, etc., without restriction. The mapping relationship between (preamble and / or RO) and PRU can be one-to-one or many-to-one, without restriction. As shown in Figure 7a, the mapping relationship between preamble and PRU is one-to-one. There is a mapping relationship between preamble#1 and PRU#1. PRU#1 contains: PO#1 and DMRS#1, and DMRS#1 contains the sequence and port information corresponding to DMRS#1. Similarly, preamble#2 to preamble#4 are mapped to PRU#2 to PRU#4 respectively. As shown in Figure 7b, the mapping relationship between preamble and PRU is many-to-one. There is a mapping relationship between (preamble#1 and premable#2) and PRU#1. PRU#1 contains: PO#1 and DMRS#1, and DMRS#1 contains the sequence and port information corresponding to DMRS#1. Similarly, (preamble#3 and preamble#4) have a mapping relationship with PRU#2.

[0158] Optionally, the “first PUSCH”, “first uplink data” or “second reference signal” in this application can be scrambled using corresponding scrambling sequences to reduce interference between different terminal devices.

[0159] 3. First reference signal

[0160] In one understanding, in the method of this application, a first reference signal is added to message A, and both the first and second reference signals are used to demodulate the first uplink data. Compared to using the second reference signal (DMRS) alone, or using the second reference signal (DMRS) and the first random access preamble to demodulate the first uplink data, the performance of demodulating the first uplink data can be improved, such as improving the accuracy of the demodulation result of the first uplink data.

[0161] The name of the first reference signal is not limited; it can also be called a pilot signal. Similarly, the second reference signal can also be called a pilot signal. The first reference signal can also be called a pre-reference signal. For example, the first PUSCH carries the second reference signal (DMRS) and the first uplink data. The first reference signal can be transmitted in the time domain before the first PUSCH, the second reference signal, or the first uplink data. That is, the first reference signal is pre-positioned relative to the first PUSCH (or the second reference signal or the first uplink data), therefore, the first reference signal can also be called a pre-reference signal.

[0162] In this application, there are no restrictions on the time-frequency resources (i.e., the time-frequency resources occupied by the first reference signal) used by the terminal device to transmit the first reference signal. For example, the aforementioned time-frequency resources may be predefined or pre-configured. Alternatively, there may be a relationship between the time-frequency resources of the first reference signal and the time-frequency resources of the second reference signal; for instance, the time-frequency resources of the first reference signal may be determined based on the time-frequency resources of the second reference signal (DMRS).

[0163] If the first and second reference signals occupy the same time-frequency domain resources but different code resources (e.g., using different sequences to distinguish them), then the first and second reference signals are considered to satisfy code division multiplexing. Similarly, if the first and second reference signals occupy the same time-domain and code resources but different frequency-domain resources (e.g., using different frequency-domain resources to distinguish them), then the first and second reference signals are considered to satisfy frequency division multiplexing. Likewise, if the first and second reference signals occupy the same frequency-domain and code resources but different time-domain resources (e.g., using different time-domain resources to distinguish them), then the first and second reference signals are considered to satisfy time division multiplexing. Furthermore, if there is a mapping relationship between the preamble and / or RO and the second reference signal, this mapping relationship can be one-to-one or many-to-one. The terminal device can determine relevant information of the second reference signal that has a mapping relationship with (the first random access preamble and / or RO) based on the determined first random access preamble and / or RO, such as the time-frequency domain resources of the second reference signal, the sequence of the second reference signal, and the port of the second reference signal. The terminal device can obtain the time-frequency domain resources of the second reference signal from the aforementioned relevant information of the second reference signal.

[0164] This application does not limit the method by which the terminal device determines the time-frequency domain resources of the first reference signal. Regardless of the method used, the time-frequency domain resources of the first reference signal are determined. In this application, the time-domain location of the first reference signal satisfies the following condition:

[0165] The time-domain interval between the second reference signal (DMRS) and the first reference signal is less than the time-domain interval between the second reference signal (DMRS) and the first random access preamble. For example, if the first reference signal occupies time-domain position 1, the second reference signal (DMRS) occupies time-domain position 2, and the first random access preamble occupies time-domain position 3, then the time-domain interval between the second reference signal (time-domain position 2) and the first reference signal (time-domain position 1) is less than the time-domain interval between the second reference signal (time-domain position 2) and the first random access preamble (time-domain position 3). This can be discussed in two cases:

[0166] Scenario 1: The second reference signal and the first reference signal occupy the same time-domain position (e.g., they occupy the same symbol), and time-domain position 1 and time-domain position 2 are the same or overlap. In this case, the time-domain interval between the second reference signal and the first reference signal is zero. However, according to the current configuration, the second reference signal and the first random access preamble are transmitted at different time-domain positions, and their time-domain interval is greater than zero. Therefore, it can be guaranteed that the time-domain interval between the second reference signal and the first reference signal is less than the time-domain interval between the second reference signal and the first random access preamble.

[0167] Scenario 2: The "first reference signal" introduced in this application can be transmitted in the time domain after the "first random access preamble" and before the "second reference signal." In other words, the time domain position occupied by the "first reference signal" is located between the "first random access preamble" and the "second reference signal." This also ensures that the time domain interval between the "second reference signal" and the "first reference signal" is less than the time domain interval between the "second reference signal" and the "first random access preamble."

[0168] For example, one TDD frame structure applicable to this application can be DDDSU. As shown in Figure 5, the terminal device transmits a first random access preamble (illustrated as preamble in Figure 5) on the U subframe of the first TDD period. The terminal device transmits a first PUSCH (illustrated as PUSCH in Figure 5) on the U subframe of the second TDD period. It can be understood that the first PUSCH carries a second reference signal (DMRS) and first uplink data. Corresponding to case 1 above, the terminal device can transmit the first reference signal on a certain symbol of the U subframe of the second TDD period. If the aforementioned certain symbol can be understood as a symbol for transmitting the second reference signal (DMRS), then it is assumed that the first reference signal and the second reference signal occupy the same time domain position (e.g., symbol), and the number of the aforementioned certain symbol can be one or more symbols without limitation. Alternatively, as in case 2 above, the terminal device can transmit the first reference signal in the time domain position between the first random access preamble (preamble) and the first PUSCH. For example, the terminal device can transmit the first reference signal in the S subframe of the second TDD period. Alternatively, the first reference signal may be transmitted on the U-frame of the second TDD cycle, but the time domain or symbol occupied by the first reference signal may be located before the second reference signal (DMRS), etc.

[0169] Another TDD frame structure applicable to this application can be: DDDSU+DDSUU. Extending the frame structure DDDSU+DDSUU, the subframes included in each TDD cycle are determined. For example, the first TDD cycle includes the subframes DDDSU+DDSUU. The second TDD cycle also includes the subframes DDDSU+DDSUU. The terminal device can transmit the first random access preamble on the 5th subframe (U subframe) of a TDD cycle and the first PUSCH on the 10th subframe (U subframe) of a TDD cycle. The first reference signal, newly added or introduced in this application, is transmitted on the 9th subframe (U subframe) of a TDD cycle, or on the 8th subframe (S subframe) of a TDD cycle. In the above TDD frame structure DDDSU+DDSUU, the uplink / downlink ratio can be considered to be 7:3. It is understood that, in this case, the S subframe is counted as a downlink subframe.

[0170] Furthermore, there are no restrictions on the sequence and port of the first reference signal. For example, the sequence and port of the first reference signal may be predefined or preconfigured. Alternatively, they may be determined based on (the first random access preamble and / or RO), etc., without restriction. For instance, in this application, the sequences corresponding to the first reference signal and the second reference signal (DMRS) may be the same, or the sequences corresponding to them may be different, such as the sequences corresponding to them being orthogonal, or the cross-correlation mean of the sequence sets to which the sequences corresponding to them belong being the same, etc. Similarly, the ports corresponding to the first reference signal and the second reference signal (DMRS) may be the same, or the ports corresponding to them may be orthogonal, etc.

[0171] Optionally, the terminal device may send a first reference signal when the first condition is met. For example, the terminal device may determine whether the first condition is currently met; if the first condition is met, the first reference signal is sent. If the first condition is not met, the first reference signal may not be sent. For example, the first condition includes: the RSRP of the system message or synchronization signal (such as SSB) received by the terminal device is less than or equal to (or less than) a fourth threshold, and / or the index of the modulation and coding scheme (MCS) of the uplink data is greater than or equal to (or greater than) a fifth threshold.

[0172] Taking SSB as an example: The terminal device can receive the SSB, measure it, and obtain the reference signal receiving power (RSRP) of the SSB. When the measured RSRP of the SSB is less than or equal to the fourth threshold, it indicates that the current wireless channel quality is poor, and it may be necessary to demodulate the first uplink data using both the first and second reference signals. In this case, the terminal device sends the first reference signal. Similarly, when the measured RSRP of the SSB is greater than the fourth threshold, it indicates that the current wireless channel quality is good. In this case, the second reference signal can demodulate the first uplink data independently, so the terminal device does not need to send the first reference signal. The terminal device not sending the first reference signal can save energy and reduce the detection complexity of the access network equipment. Optionally, the fourth threshold can be predefined, such as that predefined by the protocol, or pre-configured, such as that pre-configured by the access network equipment to the terminal device.

[0173] For example, the terminal device can determine the index of the MCS (Modulation and Coding System) for the uplink data. It can be understood that the MCS corresponding to the aforementioned MCS index is used for modulation and coding of the uplink data. A larger MCS index value indicates a higher modulation and coding rate, higher transmission efficiency, and higher requirements for channel quality. Conversely, a smaller MCS index value indicates a lower modulation and coding rate, lower transmission efficiency, and lower requirements for channel quality. The MCS index for uplink data can be predefined or pre-configured, without restriction. It can be understood that when the MCS index value is large (e.g., greater than the fifth threshold), the requirements for channel quality are high. Therefore, in this case, it may be necessary to demodulate the first uplink data using both the first reference signal and the second reference signal, with the terminal device sending the first reference signal. Similarly, when the MCS index value is small (e.g., less than or equal to the fifth threshold), the requirements for channel quality are low. In this case, the second reference signal can be used alone to demodulate the first uplink data, and the terminal device may not need to send the first reference signal. The fifth threshold can be predefined or preconfigured; there are no restrictions.

[0174] As can be seen from the above description, in the method of this application: the terminal device may or may not send the first reference signal. Optionally, the first random access preamble can be used to indicate whether to transmit (or send) the first reference signal. For example, certain sequences can be used to indicate the transmission (or sending) of the first reference signal. Other sequences can be used to indicate not to transmit (or not to send) the first reference signal. For example, the preamble can be divided into two groups, with the first group containing preambles used to indicate the transmission (or sending) of the first reference signal, and the second group containing preambles used to indicate not to transmit (or not to send) the first reference signal. In the scenario where the terminal device transmits the first reference signal, the terminal device can select one preamble from the first group and send it as the first random access preamble. In the scenario where the terminal device does not transmit the first reference signal, the terminal device can select one preamble from the second group and send it as the first random access preamble.

[0175] Accordingly, the access network device receives message A. Specifically, the access network device receives the first random access preamble on the RO corresponding to the PRACH. If the first random access preamble corresponds to a sequence, the access network device cannot accurately determine the sequence sent by the terminal device. The access network device can traverse the preamble set, group A, or all preambles contained in group B, and perform cross-correlation detection with the received sequence respectively. The preamble with the largest cross-correlation value can be considered as the preamble (first random access preamble) sent by the terminal device. Alternatively, the access network device can determine the corresponding PRU based on the mapping relationship between (RO and / or preamble) and PRU. It receives the first PUSCH on the PO contained in the PUR. Further, the access network device obtains the second reference signal (DMRS) and the first uplink data carried by the first PUSCH.

[0176] The access network equipment uses a first reference signal and a second reference signal (DMRS) to demodulate the first uplink data. Accordingly, the functions of the first and second reference signals can be described as follows: the first and second reference signals are used to demodulate the first uplink data. For example, the access network equipment can combine the first and second reference signals to perform channel estimation and obtain a channel estimation result; the access network equipment uses the channel estimation result to demodulate the first uplink data. More specifically, for example, the access network equipment can determine a first equivalent channel based on the first reference signal; determine a second equivalent channel based on the second reference signal; and determine a third equivalent channel based on the first and second equivalent channels. For example, by averaging the first and second equivalent channels, the third equivalent channel is obtained. The first uplink data is then demodulated based on the third equivalent channel. For example, the access network equipment determines a first covariance matrix based on a first equivalent channel; a second covariance matrix based on a second equivalent channel; and a third covariance matrix based on the first and second covariance matrices, such as by averaging the first and second covariance matrices. The third covariance matrix is ​​then used to demodulate the first uplink data. Specifically, joint filtering is performed based on the third covariance matrix to determine the receiving weights of the first uplink data. The first uplink data is then received / demodulated based on these receiving weights.

[0177] For example, the demodulation of the first uplink data carried by the first PUSCH mainly includes the following process:

[0178] 1. Signal reception and preprocessing: such as radio frequency reception and analog-to-digital conversion.

[0179] 2. Synchronization and timing adjustment: such as time synchronization and frequency synchronization.

[0180] 3. Cyclic prefix (CP) removal: such as removing the cyclic prefix CP of OFDM symbols, retaining the valid data portion.

[0181] 4. Fast Fourier Transform (FFT): For example, performing an FFT on a time-domain signal transforms it to the frequency domain and extracts data from the subcarriers.

[0182] 5. Channel estimation and equalization (this application focuses on improving this process): For example, the channel estimation process includes: determining the channel estimation result using the first reference signal and the second reference signal. The channel equalization process includes: equalizing the received signal based on the channel estimation result to eliminate channel distortion, etc.

[0183] 6. Demapping: Demapping frequency domain symbols from the modulation constellation diagram to soft bits or hard bits.

[0184] 7. Descrambling: Use the same scrambling sequence as the sender to descramble the data and recover the original bit stream.

[0185] 8. De-rate matching: Based on the rate matching process at the sending end, reverse the received bit stream to recover the original encoded bits.

[0186] 9. Channel Decoding: Channel coding schemes such as low-density parity-check (LDPC) codes are used to decode data and correct errors in transmission.

[0187] 10. Cyclic Redundancy Check (CRC) Verification: This involves performing a CRC check on the decoded data to verify its correctness. If the check fails, a retransmission request may be triggered, such as a hybrid automatic repeat request (HARQ).

[0188] 11. Higher-level processing: The demodulated data is passed to the MAC layer or higher levels for further processing.

[0189] Step 620: In response to message A, the access network device sends message B.

[0190] Accordingly, the terminal device receives message B.

[0191] Message B can be a response to message A. Message B indicates whether the terminal device's random access was successful, such as indicating successful random access or indicating a fallback to the four-step random access method. Message B can be understood as a RAR message for message A, which contains / carries a PDCCH or PDSCH. The PDCCH carries or bears control information, and the PDSCH carries or bears data information. As described above, message B can be briefly described as: a RAR message for message A, which contains or bears a PDCCH or PDSCH (a RAR message with a PDCCH / PDSCH for Msg A).

[0192] Example 1: Message B is used to indicate that the terminal device has successfully accessed the network.

[0193] If the access network device successfully receives / detects / demodulates the PRACH and the first PUSCH, then message B sent by the access network device is used to indicate that the terminal device has successfully accessed the network. In other words, when the access network device successfully receives / detects / demodulates both the PRACH and the first PUSCH, it sends message B to indicate that the terminal device has successfully accessed the network.

[0194] It is understood that the PRACH carries the first random access preamble, and the first PUSCH carries at least the first uplink data. In the description of this application, "the terminal device successfully (or failed to) receive / detect / demodulate the PRACH" can be replaced with: "the terminal device successfully (or failed to) receive / detect / demodulate the first random access preamble." Similarly, "the terminal device successfully (or failed to) receive / detect / demodulate the first PUSCH" can be replaced with: "the terminal device successfully (or failed to) receive / detect / demodulate the first uplink data."

[0195] Message B contains the identity identifier of the terminal device that successfully accessed the network. This identity identifier can be the complete identity identifier of the terminal device, or it can be the first N bits of the terminal device's identity identifier, where N is an integer greater than 1. When the terminal device receives message B, it can determine whether its own identity identifier is the same as or matches the contention resolution identifier contained in message B. If they are the same or match, the terminal device is considered to have successfully accessed the network; otherwise, the terminal device is considered to have failed to access the network.

[0196] Optionally, in addition to the contention resolution identifier, message B may also contain other necessary information, such as uplink grant (allocating resources to the terminal to continue communication) and timing advance command (adjusting the transmission timing of the terminal device). In one interpretation, message B is equivalent to messages 2 and 4 in the four-step random access process. For details regarding the content of message B, please refer to the descriptions of messages 2 and 4 in the four-step random access process.

[0197] In one possible implementation, the access network device detects the first random access preamble on the RO of the PRACH. Since the access network device does not know the specific preamble sent by the terminal device, it can traverse the preamble set, group A, or group B, and determine the preamble with the highest cross-correlation detection value as the first random access preamble. Further, the access network device determines the PRU (e.g., the first PRU) corresponding to the (first random access preamble and / or RO) based on the mapping relationship between (preamble and / or RO) and PRU. The first PUSCH is detected on the PO (e.g., the first PO) contained in the first PRU. If multiple terminal devices simultaneously send PUSCHs on the first PO, interference occurs between them. The access network device can only detect the strongest PUSCH on the first PO; the terminal device sending this PUSCH can be considered the successful contender. Further, uplink data is obtained from the strongest PUSCH, and further, the identification information of the terminal device contained in the uplink data is obtained. The access network device sends message B, which contains a contention resolution identifier, such as the identity information of the terminal device that successfully won the contention, or all or part of the identity information of the terminal device that succeeded in winning the contention. When the terminal device receives message B, it retrieves the contention resolution identifier contained in message B. It then determines whether the contention resolution identifier matches the terminal device's own identity identifier. If they match, the terminal device is considered to have successfully accessed the network; otherwise, the terminal device is considered to have failed to access the network.

[0198] Example 2: Message B is used to indicate a fallback to four-step random access.

[0199] For example, when the access network device receives message A: reception / detection / demodulation of PRACH is successful, but reception / detection / demodulation of the first PUSCH fails, the access network device can notify the terminal to fall back to the four-step random access procedure. Message B sent by the access network device to the terminal could be a fallback RAR. That is, when the access network device successfully receives / detects / demodulates PRACH but fails to receive / detect / demodulate the first PUSCH, it can send message B to indicate a fallback to the four-step random access procedure. Upon receiving message B, the terminal device can fall back to the four-step random access procedure and reconnect to the current or other access network devices using the four-step random access method.

[0200] Example 3: The access network device no longer sends message B.

[0201] For example, a possible scenario is that if the terminal device fails to receive / detect / demodulate both PRACH and the first PUSCH, the access network device may no longer respond to message A, such as no longer sending message B.

[0202] In this application, the terminal device can be in a disconnected state, such as an idle state or a deactivated state. For example, the terminal device may initiate random access as shown in Figure 6 when it receives a paging from the access network device, or when there is an uplink transmission requirement. The random access method shown in Figure 6 can be called two-step random access. Optionally, the terminal device can choose to initiate two-step random access or four-step random access. For example, in the disconnected state, the terminal device receives a synchronization signal (such as an SSB) from the access network device. The terminal device measures the synchronization signal and determines its RSRP. The terminal device selects the access procedure based on the measured RSRP of the synchronization signal. For example, if the RSRP of the synchronization signal measured by the terminal device is greater than a threshold, the terminal device chooses to use the two-step random access shown in Figure 6. Or, if the RSRP of the synchronization signal measured by the terminal device is less than a threshold, the terminal device chooses to use four-step random access. The aforementioned threshold can be predefined, such as protocol predefined, or pre-configured, such as pre-configured by the access network device for the terminal device.

[0203] In this application, the first PUSCH carries a second reference signal (DMRS) and first uplink data. The second reference signal itself is used to demodulate the first uplink data. In this application, a new first reference signal is added. This first reference signal and the second reference signal can be jointly used to demodulate the first uplink data. For example, the first reference signal and the second reference signal can be jointly used for channel estimation to obtain a channel estimation result; the first uplink data can then be demodulated using the corresponding channel estimation result. In this application, the first reference signal and the second reference signal can satisfy certain characteristics so that the first reference signal and the second reference signal can be jointly used to demodulate the first uplink data, or jointly used for channel estimation, etc. See the descriptions in "Possible Implementation 1", "Possible Implementation 2", and "Possible Implementation 3" below for details.

[0204] [Possible Implementation Method 1]

[0205] The time-domain interval between the first reference signal and the second reference signal is less than or equal to a first threshold. The first threshold is predefined, such as by a protocol or pre-configured, such as by the access network equipment pre-configured to the terminal equipment. It can be understood that the first reference signal and the second reference signal can be transmitted at the same time-domain position, and the value of the first threshold can be zero.

[0206] In one interpretation, the first threshold can be considered as the time-domain interval between the second reference signal (DMRS) and the first random access preamble. In this case, the time-domain interval between the second reference signal (DMRS) and the first reference signal is less than the first threshold, meaning the time-domain interval between the second reference signal (DMRS) and the first reference signal is less than the time-domain interval between the second reference signal (DMRS) and the first random access preamble.

[0207] In another interpretation, the first threshold can also be interpreted in other ways. For example, when the first reference signal and the second reference signal are located in the same uplink subframe U, the first reference signal and the second reference signal may be located in different time slots. The difference between the index of the time slot occupied by the first reference signal and the index of the time slot occupied by the second reference signal is less than or equal to the first threshold.

[0208] Regardless of the interpretation above, the possible implementation methods described above can ensure that the time-domain interval between the first reference signal and the second reference signal is small, thereby reducing the probability of a phase jump between the first reference signal and the second reference signal. This further enables the first reference signal and the second reference signal to jointly perform channel estimation, ultimately achieving demodulation of the first uplink data.

[0209] Optionally, the first reference signal and the second reference signal may also satisfy at least one of the following characteristics:

[0210] Feature 1: The cross-correlation statistics of the first reference signal sequence and the second reference signal sequence are consistent.

[0211] For example, if the cross-correlation statistics of the first reference signal sequence and the second reference signal sequence are consistent, it can be understood as follows: the first reference signal corresponds to the first sequence, and the first sequence belongs to the first sequence set. The second reference signal corresponds to the second sequence, and the second sequence belongs to the second sequence set. The mean cross-correlation of the first sequence set and the second sequence set is the same.

[0212] For example, as shown in Figure 8, there are two sequence sets: a first sequence set and a second sequence set. The first sequence set contains N reference signal sequences, whose indices are 1 to N. The second sequence set contains N DMRS sequences, whose indices are 1 to N.

[0213] For example, the mean cross-correlation between the first and second sequence sets can be calculated using the following method. For instance, if the first sequence set contains N sequences, the cross-correlation value between any two sequences can be calculated. For example, a cross-correlation function can be used to calculate or measure the cross-correlation value between any two sequences. Then, the mean of all cross-correlation values ​​is calculated as the mean cross-correlation value of the first sequence set. Similarly, the mean cross-correlation value of the second sequence set can be calculated using the same method. More specifically, both the first and second sequence sets contain N sequences. Any two sequences among these N sequences form a sequence combination. The N sequences can form a total of C(N, 2) = N*(N-1) / 2 sequence combinations. The cross-correlation values ​​of these C(N, 2) sequence combinations can be calculated separately, and finally, the mean of the cross-correlation values ​​of these C(N, 2) sequence combinations is calculated as the mean cross-correlation value of either the first or second sequence set.

[0214] Understandably, in this application, the terminal device can select a sequence (such as referred to as the first sequence) from a first sequence set to generate a first reference signal. It can also select a sequence (such as referred to as the second sequence) from a second sequence set to generate a second reference signal. The cross-correlation mean of the first sequence set and the second sequence set in this application is the same. Therefore, for the receiving end (access network equipment side), a first covariance matrix can be determined based on the first reference signal. A second covariance matrix can be determined based on the second reference signal. A third covariance matrix can be determined based on the first and second covariance matrices. The first uplink data is demodulated using the third covariance matrix. The fact that the cross-correlation mean of the first sequence set corresponding to the first reference signal and the second sequence set corresponding to the second reference signal is the same allows the interference covariance matrix determined by the receiving end to be the same or close, thereby making the demodulation result of the first uplink data more accurate and improving the demodulation performance of the first PUSCH.

[0215] Understandably, besides the mean cross-correlation, other parameters can be used to measure the cross-correlation characteristics between the sequences corresponding to the first reference signal and the sequences corresponding to the second reference signal. These could include the cumulative distribution function (CDF) curve or the probability density function (PDF) curve. For example, the CDF curves for the first sequence set and the second sequence set can be determined separately. If the CDF curves for the first sequence set and the second sequence set are the same or similar, then the cross-correlation characteristics of the first sequence set corresponding to the first reference signal and the second sequence set corresponding to the second reference signal are considered to be consistent.

[0216] In one possible implementation, the first sequence corresponding to the first reference signal and the second sequence corresponding to the second reference signal can be the same. That is, the same sequence can be used to generate the first reference signal and the second reference signal.

[0217] Feature 2: The first reference signal and the second reference signal have the same transmission power, or the difference between their transmission power is a known value.

[0218] For example, characteristic 2 described above can make the power statistical characteristics of the first reference signal and the second reference signal consistent, or the difference between their power statistical characteristics is known. For example, if the first reference signal and the second reference signal have the same transmission power, the first reference signal and the second reference signal will be affected by noise in the same or consistent way. If the first reference signal and the second reference signal have the same transmission power, then the first reference signal and the second reference signal have the same coverage area, and they will be subject to the same noise interference. Furthermore, if the first equivalent channel determined based on the first reference signal and the second equivalent channel determined based on the second reference signal are the same or close, a more accurate channel estimate can be obtained, improving the demodulation performance of the first uplink data. Alternatively, if the difference in transmission power between the first reference signal and the second reference signal is a known value (e.g., the noise interference they are subject to can be considered a known value), the receiver can assign different weighting coefficients to the first equivalent channel corresponding to the first reference signal and the second equivalent channel corresponding to the second reference signal based on the difference in their transmission power, thereby also obtaining a more accurate channel estimate.

[0219] Feature 3: The transmission beams of the first reference signal and the second reference signal are the same.

[0220] For example, characteristic 3 mentioned above can make the spatial statistical characteristics of the first reference signal and the second reference signal consistent. If the first reference signal and the second reference signal are transmitted using the same beam, the first reference signal and the second reference signal are subject to the same interference from other users (terminal devices) in the spatial domain, thereby obtaining an accurate interference protocol variance matrix, further making the obtained channel estimate more accurate, and improving the demodulation performance of the first uplink data.

[0221] Feature 4: The frequency domain spacing between the first reference signal and the second reference signal is less than or equal to the third threshold; or, the first reference signal and the second reference signal occupy the same bandwidth; or, the bandwidth occupied by the first reference signal and the second reference signal belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth. Optionally, the third threshold can be predefined, such as that predefined by the protocol, or preconfigured, such as that preconfigured by the access network equipment to the terminal equipment.

[0222] For example, characteristic 4 described above can make the frequency domain statistical characteristics of the first reference signal and the second reference signal consistent or similar. This characteristic allows the access network device to directly use the channel characteristics estimated based on the first or second reference signal to demodulate the first uplink data carried by the PUSCH.

[0223] Feature 5: The mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

[0224] For example, if the mapping relationship between the first random access preamble and the first reference signal is one-to-one, then the mapping relationship between the first random access preamble and the second reference signal (DMRS) is also one-to-one. Furthermore, if the mapping relationship between the first random access preamble and the first reference signal is many-to-one, then the mapping relationship between the first random access preamble and the second reference signal (DMRS) is also many-to-one.

[0225] Optionally, in the above mapping relationship, RO may also be replaced or included. For example, the mapping relationship between the first random access preamble and the first reference signal can be replaced by: the mapping relationship between (the first random access preamble and / or RO) and the first reference signal. The mapping relationship between the first random access preamble and the second reference signal can be replaced by: the mapping relationship between (the first random access preamble and / or RO) and the second reference signal. The description of feature 5 above can be replaced by: the mapping relationship between (the first random access preamble and / or RO) and the first reference signal is the same as the mapping relationship between (the first random access preamble and / or RO) and the second reference signal. Feature 5 can make the interference levels of the first reference signal and the second reference signal consistent or the same.

[0226] It is understandable that the second reference signal can be DMRS, and the PRU contains information such as PO and DMRS. Therefore, the mapping relationship between the first random access preamble and the second reference signal (DMRS) can be replaced by the mapping relationship between the first random access preamble and the PRU.

[0227] As shown in Figure 9a, there is a one-to-one mapping relationship between the preamble, the first reference signal, and the PRU. For example, there is a one-to-one mapping relationship between preamble #1, the first reference signal #1, and PRU #1. PRU #1 includes PO #1 and the second reference signal #1 (DMRS #1), such as the port and / or sequence of DMRS #1. Similarly, there is a one-to-one mapping relationship between preamble #2, the first reference signal #2, and PRU #2. There is also a one-to-one mapping relationship between preamble #3, the first reference signal #3, and PRU #3.

[0228] As shown in Figure 9b, there is a many-to-one mapping relationship between the preamble, the first reference signal, and the PRU. For example, there is a mapping relationship between (preamble#1 and peamble#2), the first reference signal #1, and PRU#1. (preamble#1 and peamble#2) corresponds to one first reference signal #1, and (preamble#1 and peamble#2) corresponds to one PRU#1. It can be understood that PRU#1 includes PO#1 and the second reference signal #1 (DMRS#1), such as the port and / or sequence of DMRS#1. Similarly, (preamble#3 and peamble#4) corresponds to one first reference signal #2, and (preamble#3 and peamble#4) corresponds to one PRU#2.

[0229] In one understanding, as shown in Figure 7a or Figure 7b, a mapping relationship exists between the preamble and the PRU. Specifically, as shown in Figure 7a, the mapping relationship between the preamble and the PRU can be one-to-one, or as shown in Figure 7b, the mapping relationship can be many-to-one. In this application, a first reference signal is introduced and added to the above mapping relationship to establish a mapping relationship between the preamble, the first reference signal, and the PUR. The above mapping relationship can be one-to-one, as shown in Figure 9a. Alternatively, the above mapping relationship can be many-to-one, as shown in Figure 9b.

[0230] For example, as shown in Figure 9b, the mapping relationship between premable, first reference signal, and PRU is as follows: many to one, that is, multiple premables correspond to one first reference signal, and multiple preambles correspond to one PRU, which contains second parameter signals (DMRS), such as the port and / or sequence of DMRS.

[0231] It is understandable that multiple terminal devices may use different prembles for access, such as preamble #1 and premable #2 as described above. According to the mapping relationship shown in Figure 9b, the PRUs of the first reference signal and the second reference signal (DMRS) corresponding to these multiple terminal devices are also the same. There is mutual interference between the first reference signals transmitted by these multiple terminal devices; similarly, there is also mutual interference between the second reference signals (DMRS) transmitted by these multiple terminals. Since the mapping relationship between the first reference signal and the preamble is consistent with the mapping relationship between the second reference signal (DMRS) and the preamble, it can be guaranteed that the interference experienced by the second reference signal and the first reference signal is the same or similar.

[0232] It is understandable that in the above [possible implementation method 1], in one possible implementation method: the first reference signal and the second reference signal can occupy the same frequency domain resources and code domain resources, and the first reference signal and the second reference signal are distinguished by different time domain resources, that is, the first reference signal and the second reference signal occupy different time domain resources. At this time, the relationship between the first reference signal and the second reference signal is time division multiplexing.

[0233] [Possible Implementation Method 2]

[0234] The relationship between the first reference signal and the second reference signal is frequency division multiplexing. For example, the first reference signal and the second reference signal occupy different frequency domain resources. For instance, the first reference signal occupies frequency domain resource 1, and the second reference signal occupies frequency domain resource 2. Frequency domain resource 1 and frequency domain resource 2 are different; for example, frequency domain resource 1 and frequency domain resource 2 may not intersect at all, or they may partially intersect. Furthermore, the first reference signal and the second reference signal occupy the same time domain resources and code domain resources, etc.

[0235] Furthermore, the frequency domain spacing between the first reference signal and the second reference signal is limited, for example, the frequency domain spacing between frequency domain resource 1 and frequency domain resource 2 is limited. For instance, the frequency domain spacing between the first reference signal and the second reference signal is less than or equal to a third threshold. This ensures that the frequency domain resources occupied by the first reference signal and the second reference signal are close, avoiding a large gap between their occupied frequency domain resources. Optionally, the third threshold can be predefined, or pre-configured, and not limited.

[0236] Alternatively, the bandwidths of the first and second reference signals can be limited. For example, bandwidth refers to the frequency band width occupied by the signal. The bandwidth of the first reference signal refers to the frequency band width occupied by the first reference signal, such as the frequency band width of frequency domain resource 1 mentioned above. The bandwidth of the second reference signal refers to the frequency band width occupied by the second reference signal, such as the frequency band width of frequency domain resource 2 mentioned above. Optionally, the bandwidths of the first and second reference signals can be the same, or the bandwidths they occupy belong to a coherent bandwidth, and the channel characteristics within a coherent bandwidth are correlated. For example, the bandwidth of the first reference signal can be described as bandwidth 1, and the bandwidth of the second reference signal can be described as bandwidth 2. Bandwidth 1 and bandwidth 2 can be considered to belong to a coherent bandwidth, such as if this coherent bandwidth includes bandwidth 1 and bandwidth 2. It can be understood that the channel characteristics of channels corresponding to multiple bandwidths included in the same coherent bandwidth are correlated. For example, if the first reference signal corresponds to bandwidth 1, and the second reference signal corresponds to bandwidth 2, and bandwidth 1 and bandwidth 2 belong to the same coherent bandwidth, then the channel characteristics of the channels corresponding to the first and second reference signals are the same or similar.

[0237] Optionally, the first reference signal and the second reference signal may also satisfy at least one of the following characteristics: characteristic 1, characteristic 2, characteristic 3, or characteristic 5. For a detailed explanation of the above characteristics 1, 2, 3, and 5, please refer to the relevant explanation of [Possible Implementation 1] above.

[0238] [Possible Implementation Method 3]

[0239] The relationship between the first reference signal and the second reference signal is code division multiplexing. The first and second reference signals may correspond to different code resources (sequences). For example, the first reference signal may correspond to a first sequence, and the second reference signal may correspond to a second sequence, and the first and second sequences are different. The first and second reference signals may occupy the same time-domain and frequency-domain resources; for example, they may occupy the same symbols and the same bandwidth.

[0240] If the first reference signal corresponds to the first sequence, the second reference signal corresponds to the second sequence, the first sequence belongs to the first sequence set, the second sequence belongs to the second sequence set, the first sequence and the second sequence both belong to the third sequence set, and the cross-correlation mean of the first sequence set, the second sequence set and the third sequence set is the same.

[0241] If the mean cross-correlation of the third sequence set is the third value, the mean cross-correlation of the first sequence set is the first value, and the mean cross-correlation of the second sequence set is the second value, then the third, first, and second values ​​are all the same. For the process of calculating the mean cross-correlation of each sequence set, please refer to the explanation in

Possible Implementation Method 1

[0242] For example, as shown in Figure 10, the first sequence set contains N reference signal sequences, with indices from 1 to N. It can be understood that the "first sequence corresponding to the first reference signal" can be any one of the N reference signal sequences. The second sequence set contains N DMRS sequences, with indices from 1 to N. It can be understood that the "second sequence corresponding to the second reference signal" can be any one of the N DMRS sequences. The third sequence set contains both the N reference signal sequences and the N DMRS sequences, or it can be considered that the third sequence set contains both the first and second sequence sets. It can be understood that the "first sequence corresponding to the first reference signal" and the "second sequence corresponding to the second reference signal" both belong to the third sequence set. The first, second, and third sequence sets shown in Figure 10 have the same mean cross-correlation.

[0243] It is understandable that, besides the mean cross-correlation, other methods can be used to measure the cross-correlation of the three sequence sets mentioned above. For example, the CDF curves: the CDF curves corresponding to the first, second, and third sequence sets are the same or similar. Similarly, the PDF curves: the PDF curves corresponding to the first, second, and third sequence sets are the same or similar, and so on.

[0244] Optionally, the first reference signal and the second reference signal may also satisfy at least one of the following characteristics: characteristic 2 or characteristic 3. For details regarding characteristic 2 and characteristic 3, please refer to the description in [Possible Implementation Method 1] above.

[0245] In the above method, in the two-step random access scenario, a first reference signal is added. The first reference signal and the original second reference signal (DMRS) are used together for channel estimation to improve the accuracy of the channel estimation results and improve the demodulation performance of the first uplink data.

[0246] In the embodiments provided above, the methods provided by the embodiments of this application are described from the perspective of the interaction between the terminal device and the access network device. To implement the functions of the methods provided by the embodiments of this application, the terminal device and the access network device may include hardware structures and / or software modules, implementing the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the design constraints of the specific application of the technical solution.

[0247] Based on the same conceptual framework as the above-described method embodiments, Figures 11 and 12 are schematic diagrams of possible communication devices provided in the embodiments of this application. These communication devices can implement the functions of terminal devices or access network devices in the above-described method embodiments, and therefore may achieve the beneficial effects of the above-described method embodiments. In the embodiments of this application, the communication device may be a terminal device, an access network device, or a unit, module, or component (such as a chip, chip system, circuit, processor, or others) applied in a terminal device or access network device. In the following description, the term "unit" will be used as an example. For example, in the following description, the communication device will be described as including a processing unit and a transceiver unit. The processing unit in the following description may also be replaced by: a processing module or a processing component, etc. The transceiver unit may also be replaced by: a transceiver unit or a transceiver component. For example, a transceiver component may refer to a communication module.

[0248] As shown in Figure 11, the communication device 1100 includes a processing unit 1110 and a transceiver unit 1120. The communication device 1100 is used to implement the functions of the terminal device or access network device in Figure 6 above.

[0249] Optionally, the transceiver unit 1120 may also be referred to as an output unit, an interface unit, or a communication unit, etc. In one possible implementation, the transceiver unit 1120 includes at least one of a transmitting unit or a receiving unit. The transmitting unit and the receiving unit may be integrated together, or they may be two independent units, etc.

[0250] In one possible implementation, the communication device 1100 is used to implement the functions of the terminal device in FIG6. Specifically, the transceiver unit 1120 is used to send message A, which includes a first random access preamble, a first reference signal, and a Physical Uplink Shared Channel (PUSCH). The PUSCH includes first uplink data and a second reference signal. The first reference signal and the second reference signal are used to demodulate the first uplink data. The time-domain interval between the second reference signal and the first reference signal is less than the time-domain interval between the second reference signal and the first random access preamble. The transceiver unit 1120 is also used to receive message B, which is in response to message A. Message B is used to indicate that the terminal device has successfully accessed the network, or to indicate a fallback to four-step random access. Optionally, the processing unit 1110 is used to generate message A and / or process message B, etc.

[0251] For example, in one possible implementation, the time-domain interval between the first reference signal and the second reference signal is less than or equal to a first threshold, which is predefined or preconfigured.

[0252] In one possible implementation, the first reference signal and the second reference signal satisfy at least one of the following properties: the cross-correlation statistics of the sequences of the first reference signal and the second reference signal are consistent; the transmission power of the first reference signal and the second reference signal is the same, or the difference between their transmission powers is a known value; the transmission beams of the first reference signal and the second reference signal are the same; the frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the bandwidth occupied by the first reference signal and the second reference signal is the same, or the bandwidth occupied by the two signals belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth; the mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

[0253] In one possible implementation, the relationship between the first reference signal and the second reference signal is frequency division multiplexing; wherein the frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidth occupied by the two belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth.

[0254] In one possible implementation, the first reference signal and the second reference signal satisfy at least one of the following properties: the cross-correlation statistics of the sequences of the first reference signal and the second reference signal are consistent; the transmission power of the first reference signal and the second reference signal is the same, or the difference between their transmission powers is a known value; the transmission beams of the first reference signal and the second reference signal are the same; and the mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

[0255] In one possible implementation, the cross-correlation statistical characteristics of the sequences of the first reference signal and the second reference signal are consistent, including: the first reference signal corresponds to a first sequence, the first sequence belongs to a first sequence set, the second reference signal corresponds to a second sequence, the second sequence belongs to a second sequence set, and the cross-correlation mean of the first sequence set and the second sequence set is the same.

[0256] In one possible implementation, the first reference signal and the second reference signal are related by code division multiplexing. The first reference signal corresponds to a first sequence, and the second reference signal corresponds to a second sequence. The first sequence belongs to a first sequence set, the second sequence belongs to a second sequence set, and the first and second sequences belong to a third sequence set. The mean cross-correlation values ​​of the third sequence set, the first sequence set, and the second sequence set are the same.

[0257] In one possible implementation, the first reference signal and the second reference signal satisfy at least one of the following characteristics: the first reference signal and the second reference signal have the same transmission power, or the difference between their transmission power is a known value; the first reference signal and the second reference signal have the same transmission beam.

[0258] In one possible implementation, the processing unit 1110 is further configured to determine that a first condition is met; wherein the first condition includes: the reference signal received power RSRP of the received system message is less than or equal to a fourth threshold, and / or the index of the modulation and coding scheme MCS of the uplink data is greater than or equal to a fifth threshold.

[0259] In one possible implementation, the first random access preamble is used to indicate whether the first reference signal should be transmitted.

[0260] In one possible implementation, the communication device 1100 is used to implement the functions of the access network device in FIG6. Specifically, the transceiver unit 1120 is used to receive message A, which includes a first random access preamble, a first reference signal, and a Physical Uplink Shared Channel (PUSCH). The PUSCH includes first uplink data and a second reference signal. The first reference signal and the second reference signal are used to demodulate the first uplink data. The time-domain interval between the second reference signal and the first reference signal is less than the time-domain interval between the second reference signal and the first random access preamble. The transceiver unit 1120 is also used to send message B, which is a response to message A. Message B is used to indicate that the terminal device has successfully accessed the network, or to indicate a fallback to four-step random access. Optionally, the processing unit 1110 is used to generate message B and / or process message A, etc.

[0261] For example, in one possible implementation, the time-domain interval between the first reference signal and the second reference signal is less than or equal to a first threshold, which is predefined or preconfigured.

[0262] In one possible implementation, the first reference signal and the second reference signal satisfy at least one of the following properties: the cross-correlation statistics of the sequences of the first reference signal and the second reference signal are consistent; the transmission power of the first reference signal and the second reference signal is the same, or the difference between their transmission powers is a known value; the transmission beams of the first reference signal and the second reference signal are the same; the frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the bandwidth occupied by the first reference signal and the second reference signal is the same, or the bandwidth occupied by the two signals belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth; the mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

[0263] In one possible implementation, the relationship between the first reference signal and the second reference signal is frequency division multiplexing; wherein the frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidth occupied by the two belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth.

[0264] In one possible implementation, the first reference signal and the second reference signal satisfy at least one of the following properties: the cross-correlation statistics of the sequences of the first reference signal and the second reference signal are consistent; the transmission power of the first reference signal and the second reference signal is the same, or the difference between their transmission powers is a known value; the transmission beams of the first reference signal and the second reference signal are the same; and the mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

[0265] In one possible implementation, the cross-correlation statistical characteristics of the sequences of the first reference signal and the second reference signal are consistent, including: the first reference signal corresponds to a first sequence, the first sequence belongs to a first sequence set, the second reference signal corresponds to a second sequence, the second sequence belongs to a second sequence set, and the cross-correlation mean of the first sequence set and the second sequence set is the same.

[0266] In one possible implementation, the relationship between the first reference signal and the second reference signal is code division multiplexing.

[0267] In one possible implementation, the first reference signal corresponds to a first sequence, the second reference signal corresponds to a second sequence, the first sequence belongs to a first sequence set, the second sequence belongs to a second sequence set, the first sequence and the second sequence belong to a third sequence set, and the cross-correlation mean of the third sequence set, the first sequence set and the second sequence set is the same.

[0268] In one possible implementation, the first reference signal and the second reference signal satisfy at least one of the following characteristics: the first reference signal and the second reference signal have the same transmission power, or the difference between their transmission power is a known value; the first reference signal and the second reference signal have the same transmission beam.

[0269] In one possible implementation, the first reference signal is transmitted under the condition that a first condition is met; wherein the first condition includes: the reference signal received power RSRP of the received system message is less than or equal to a fourth threshold, and / or the index of the modulation and coding scheme MCS of the uplink data is greater than or equal to a fifth threshold.

[0270] In one possible implementation, the first random access preamble is used to indicate whether the first reference signal should be transmitted.

[0271] For details on the specific implementation process of the communication device 1100, please refer to the description of the terminal equipment side or access network equipment side in the method shown in Figure 6, which will not be repeated here.

[0272] It is understood that the division of units in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods. In addition, the functional units in this application embodiment can be integrated into a physical device (e.g., in a processor), or each functional unit can be a separate physical device, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional module, etc.

[0273] As shown in Figure 12, the communication device 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are coupled to each other. It is understood that the interface circuit 1220 can be a transceiver or an input / output interface. Optionally, the communication device 1200 may also include a memory 1230 for storing instructions executed by the processor 1210, or storing input data required by the processor 1210 to execute instructions, or storing data generated after the processor 1210 executes instructions.

[0274] When the communication device 1200 is used to implement the method shown in FIG6, the processor 1210 is used to implement the function of the processing unit 1110, and the interface circuit 1220 is used to implement the function of the transceiver unit 1120.

[0275] When the aforementioned communication device is a chip applied to a terminal device, the chip implements the functions of the terminal device in the above method embodiments. The chip receives information sent to the terminal device by the access network device through other modules (such as a radio frequency module or antenna) in the terminal device; or, the chip sends information to other modules (such as a radio frequency module or antenna) in the terminal device, which is information sent by the terminal device to the access network device.

[0276] When the aforementioned communication device is a module applied to an access network device, the module implements the functions of the access network device in the above method embodiments. For example, the module receives information from other modules (such as radio frequency modules or antennas) in the access network device, and this information is sent by the terminal device to the access network device; or, the module sends information to other modules (such as radio frequency modules or antennas) in the access network device, and this information is sent by the access network device to the terminal device. Here, the module of the access network device can be a chip of the access network device, or a DU (Distributed Unit) or other modules. Here, the DU can be a DU under the O-RAN architecture.

[0277] This application also provides a communication device, which includes a processor for implementing the functions of the terminal device or access network device shown in FIG6. Optionally, the communication device further includes a memory, with the processor coupled to the memory. The processor executes computer programs or instructions stored in the memory to implement the functions of the terminal device or access network device shown in FIG6. Optionally, the communication device may be a chip or a chip system.

[0278] This application embodiment also provides a communication device, including a processor and an interface circuit. The interface circuit is used to receive signals from other devices outside the device and transmit them to the processor, or to send signals from the processor to other devices outside the device. The processor is used to implement the functions of the terminal device or access network device in FIG6 above through logic circuits or execution code instructions.

[0279] This application also provides a computer-readable storage medium storing instructions, which may also be referred to as computer programs, computer program code, etc. These instructions, when executed on a computer, cause the computer to perform the functions of the terminal device or access network device shown in Figure 6 above.

[0280] This application also provides a computer program product, including a computer program or instructions, which, when run on a computer, implement the functions of the terminal device or access network device shown in FIG6 above.

[0281] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0282] The memory in the embodiments of this application may be random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), register, hard disk, portable hard disk, CD-ROM, or any other form of storage medium known in the art.

[0283] The method steps in the embodiments of this application can be implemented in hardware or in software instructions executable by a processor. The software instructions can consist of corresponding software modules, which 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 disks, portable hard disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. The storage medium can also be a component of the processor. The processor and the storage medium can reside in an ASIC.

[0284] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. This computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can 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 can 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 can be any available medium accessible to a computer or a data storage device such as a server or data center integrating one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0285] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

Claims

1. A communication method, characterized in that, include: Send message A, which includes a first random access preamble, a first reference signal, and a physical uplink shared channel (PUSCH). The PUSCH includes first uplink data and a second reference signal. The first reference signal and the second reference signal are used to demodulate the first uplink data. The time-domain interval between the second reference signal and the first reference signal is less than the time-domain interval between the second reference signal and the first random access preamble. Message B is received in response to message A. Message B is used to indicate that the terminal device has successfully accessed the random access, or to indicate a fallback to the four-step random access.

2. The method as described in claim 1, characterized in that, The time-domain interval between the first reference signal and the second reference signal is less than or equal to a first threshold, which is predefined or preconfigured.

3. The method as described in claim 2, characterized in that, The first reference signal and the second reference signal satisfy at least one of the following properties: The cross-correlation statistics of the first reference signal sequence and the second reference signal sequence are consistent; The first reference signal and the second reference signal have the same transmission power, or the difference between their transmission powers is a known value; The first reference signal and the second reference signal have the same transmission beam; The frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidth occupied by the two belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth. The mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

4. The method as described in claim 1, characterized in that, The relationship between the first reference signal and the second reference signal is frequency division multiplexing; Wherein, the frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidth occupied by the two belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth.

5. The method as described in claim 4, characterized in that, The first reference signal and the second reference signal satisfy at least one of the following properties: The cross-correlation statistics of the first reference signal sequence and the second reference signal sequence are consistent; The first reference signal and the second reference signal have the same transmission power, or the difference between their transmission powers is a known value; The first reference signal and the second reference signal have the same transmission beam; The mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

6. The method as described in claim 3 or 5, characterized in that, The cross-correlation statistical properties of the sequences of the first reference signal and the second reference signal are consistent, including: The first reference signal corresponds to a first sequence, which belongs to a first sequence set. The second reference signal corresponds to a second sequence, which belongs to a second sequence set. The cross-correlation mean of the first sequence set and the second sequence set is the same.

7. The method as described in claim 1, characterized in that, The relationship between the first reference signal and the second reference signal is code division multiplexing.

8. The method as described in claim 7, characterized in that, The first reference signal corresponds to a first sequence, the second reference signal corresponds to a second sequence, the first sequence belongs to a first sequence set, the second sequence belongs to a second sequence set, the first sequence and the second sequence belong to a third sequence set, and the mean cross-correlation of the third sequence set, the first sequence set and the second sequence set is the same.

9. The method as described in claim 7 or 8, characterized in that, The first reference signal and the second reference signal satisfy at least one of the following properties: The first reference signal and the second reference signal have the same transmission power, or the difference between their transmission power is a known value; The first reference signal and the second reference signal have the same transmission beam.

10. The method according to any one of claims 1 to 9, characterized in that, Also includes: The first condition is met; The first condition includes: the reference signal received power (RSRP) of the received system message is less than or equal to a fourth threshold, and / or the index of the modulation and coding scheme (MCS) of the uplink data is greater than or equal to a fifth threshold.

11. The method according to any one of claims 1 to 10, characterized in that, The first random access preamble is used to indicate whether the first reference signal should be transmitted.

12. A communication method, characterized in that, include: Receive message A, which includes a first random access preamble, a first reference signal, and a physical uplink shared channel (PUSCH). The PUSCH includes first uplink data and a second reference signal. The first reference signal and the second reference signal are used to demodulate the first uplink data. The time-domain interval between the second reference signal and the first reference signal is less than the time-domain interval between the second reference signal and the first random access preamble. Send message B, which is a response to message A. Message B is used to indicate that the terminal device has successfully accessed the random access, or to indicate a fallback to the four-step random access.

13. The method as described in claim 12, characterized in that, The time-domain interval between the first reference signal and the second reference signal is less than or equal to a first threshold, which is predefined or preconfigured.

14. The method as described in claim 13, characterized in that, The first reference signal and the second reference signal satisfy at least one of the following properties: The cross-correlation statistics of the first reference signal sequence and the second reference signal sequence are consistent; The first reference signal and the second reference signal have the same transmission power, or the difference between their transmission powers is a known value; The first reference signal and the second reference signal have the same transmission beam; The frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidth occupied by the two belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth. The mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

15. The method as described in claim 12, characterized in that, The relationship between the first reference signal and the second reference signal is frequency division multiplexing; Wherein, the frequency domain interval between the first reference signal and the second reference signal is less than or equal to a third threshold, or the first reference signal and the second reference signal occupy the same bandwidth, or the bandwidth occupied by the two belongs to a coherent bandwidth, and the channel characteristics of the channel are correlated within a coherent bandwidth.

16. The method as described in claim 15, characterized in that, The first reference signal and the second reference signal satisfy at least one of the following properties: The cross-correlation statistics of the first reference signal sequence and the second reference signal sequence are consistent; The first reference signal and the second reference signal have the same transmission power, or the difference between their transmission powers is a known value; The first reference signal and the second reference signal have the same transmission beam; The mapping relationship between the first random access preamble and the first reference signal is the same as the mapping relationship between the first random access preamble and the second reference signal.

17. The method as described in claim 14 or 16, characterized in that, The cross-correlation statistical properties of the sequences of the first reference signal and the second reference signal are consistent, including: The first reference signal corresponds to a first sequence, which belongs to a first sequence set. The second reference signal corresponds to a second sequence, which belongs to a second sequence set. The cross-correlation mean of the first sequence set and the second sequence set is the same.

18. The method as described in claim 12, characterized in that, The relationship between the first reference signal and the second reference signal is code division multiplexing.

19. The method as described in claim 18, characterized in that, The first reference signal corresponds to a first sequence, the second reference signal corresponds to a second sequence, the first sequence belongs to a first sequence set, the second sequence belongs to a second sequence set, the first sequence and the second sequence belong to a third sequence set, and the mean cross-correlation of the third sequence set, the first sequence set and the second sequence set is the same.

20. The method as described in claim 18 or 19, characterized in that, The first reference signal and the second reference signal satisfy at least one of the following properties: The first reference signal and the second reference signal have the same transmission power, or the difference between their transmission power is a known value; The first reference signal and the second reference signal have the same transmission beam.

21. The method according to any one of claims 12 to 20, characterized in that, The first reference signal is sent under the condition that the first condition is met; The first condition includes: the reference signal received power (RSRP) of the received system message is less than or equal to a fourth threshold, and / or the index of the modulation and coding scheme (MCS) of the uplink data is greater than or equal to a fifth threshold.

22. The method according to any one of claims 12 to 21, characterized in that, The first random access preamble is used to indicate whether the first reference signal should be transmitted.

23. A communication device, characterized in that, Includes units for implementing the method as described in any one of claims 1 to 11.

24. A communication device, characterized in that, Includes a processor configured to cause the communication device to perform the method as described in any one of claims 1 to 11.

25. A communication device, characterized in that, Includes units for implementing the method as described in any one of claims 12 to 22.

26. A communication device, characterized in that, Includes a processor configured to cause the communication device to perform the method as described in any one of claims 12 to 22.

27. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed, cause the communication device to perform the method as described in any one of claims 1 to 11, or the method as described in any one of claims 12 to 22.

28. A computer program product, characterized in that, The computer program product includes instructions that, when executed, cause the communication device to perform the method as described in any one of claims 1 to 11, or the method as described in any one of claims 12 to 22.

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