Communication method and apparatus

Abstract

The present application relates to the technical field of communications. Disclosed are a communication method and apparatus. The method comprises: a reader / writer sending first information to an A-IoT device, wherein the first information is used for indicating a first length of a first preamble; and the A-IoT device sending a PDRCH to the reader / writer, wherein the PDRCH comprises the first preamble and first data, the first preamble being located before the first data, and the first preamble being used for the synchronization of the first data. In the solution of the present application, the reader / writer indicates a first length of a first preamble, and performs uplink synchronization on the basis of the first length to receive first data, and thus the flexible indication of the length of a preamble is realized, thereby reducing signal synchronization overheads while ensuring uplink synchronization performance.

Description

Communication methods and devices

[0001] This application claims priority to Chinese Patent Application No. 202510134153.3, filed on February 6, 2025, entitled "Communication Method and Apparatus", and to Chinese Patent Application No. 202510134153.3, filed on March 27, 2025, entitled "Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0003] Ambient Internet of Things (A-IoT) devices use a time-slot-based asynchronous access method to complete random access, and A-IoT devices that successfully access the network can then transmit data.

[0004] However, current uplink data transmission uses a fixed-length preamble. The receiver uses this preamble for frame synchronization. Generally, to ensure the performance of edge devices, this preamble is relatively long. When the SNR of A-IoT devices is high, using a long preamble leads to greater signaling overhead. Summary of the Invention

[0005] This application provides a communication method and apparatus to flexibly indicate the length of the preamble, thereby reducing the overhead of the synchronization signal while ensuring uplink synchronization performance.

[0006] Firstly, a communication method is provided that can be applied to A-IoT devices, which may be A-IoT equipment or communication modules within A-IoT devices, or circuits or chips applied to A-IoT devices (such as modem chips (also known as baseband chips), or system-on-chip (SoC) chips or system-in-package (SIP) chips containing modem cores). Taking the application of this method to A-IoT devices as an example...

[0007] In this method, the A-IoT device receives first information, wherein the first information is used to indicate a first length of a first preamble; and transmits a physical device-to-reader channel (PDRCH), the PDRCH including the first preamble and first data, wherein the first preamble is located before the first data and is used for synchronization of the first data.

[0008] Using this method, the A-IoT device receives a first preamble of a first length indicated by the reader and sends first data based on that first length. This allows for flexible indication of the preamble length, reducing synchronization signal overhead while ensuring uplink synchronization performance. For example, the reader can indicate a shorter preamble to an A-IoT device with a higher received SNR based on the device's signal-to-noise ratio (SNR). In this case, because the A-IoT device has a higher SNR, the shorter preamble can still achieve higher timing performance, and the preamble overhead is relatively reduced compared to a longer preamble.

[0009] Secondly, a communication method is provided that can be applied to a reader / writer device, which may be a reader / writer or a communication module within a reader / writer, or a circuit or chip applied to the reader / writer (such as a modem chip, or a SoC chip or SIP chip containing a modem core). Taking the application of this method to a reader / writer as an example...

[0010] In this method, the reader sends first information, wherein the first information is used to indicate a first length of a first preamble; and receives a PDRCH, the PDRCH including the first preamble and first data, wherein the first preamble is located before the first data and is used for synchronization of the first data.

[0011] Using this method, the reader can receive the first data by indicating the first length of the first preamble of the A-IoT device and performing uplink synchronization based on the first length. This allows for flexible indication of the preamble length, thereby reducing the overhead of the synchronization signal while ensuring uplink synchronization performance.

[0012] In conjunction with the first or second aspect, in one possible implementation, the first information is used to indicate a first length of the first preamble, including: the first information includes a first index, the first index corresponding to the first length.

[0013] In this approach, each preamble length corresponds to an index, and A-IoT devices and readers can pre-store the correspondence between the length of at least one preamble and at least one index. This first information includes a first index, which corresponds to a first length; that is, the length of the preamble is communicated to the A-IoT device via an index indicating the preamble length.

[0014] In conjunction with the first or second aspect, in yet another possible implementation, the first information is used to indicate a first length of the first preamble, including: the first information is used to configure transmission parameters of the first data, the transmission parameters corresponding to the first length.

[0015] This approach, due to the shorter preamble length (i.e., using a short sequence), is generally suitable for scenarios where A-IoT devices have a high SNR (Signal NR). In such cases, A-IoT devices typically use a higher code rate and a larger transmission bandwidth to transmit data. Conversely, when the SNR of A-IoT devices is low, to improve transmission accuracy, a smaller transmission bandwidth is generally used to increase the power spectral density, while a lower code rate and a higher repetition count are used to further improve transmission accuracy. Therefore, the preamble length has a certain correlation with the data transmission bandwidth, code rate, and repetition count. These values ​​can be used to implicitly indicate the preamble length, thus saving the overhead of indicating the initial length.

[0016] In conjunction with the first or second aspect, in another possible implementation, the transmission parameters of the first data include at least one of the following: the transmission bandwidth of the first data, the number of repetitions of the first data, and the bit rate of the first data.

[0017] In conjunction with the first or second aspect, in another possible implementation, the first length is A bits if at least one of the following first conditions is met: the transmission bandwidth of the first data is less than or equal to a first threshold; or, the number of repetitions of the first data is greater than or equal to a second threshold; or, the code rate of the first data is less than or equal to a third threshold; and the first length is B bits if at least one of the following second conditions is met: the transmission bandwidth of the first data is greater than the first threshold; or, the number of repetitions of the first data is less than the second threshold; or, the code rate of the first data is greater than the third threshold; wherein A is greater than B, and A and B are both positive integers.

[0018] This approach, due to the shorter preamble length (i.e., using a short sequence), is generally suitable for scenarios where A-IoT devices have a high SNR (Signal NR). In such cases, A-IoT devices typically use a higher code rate and a larger transmission bandwidth to transmit data. Conversely, when the SNR of A-IoT devices is low, to improve transmission accuracy, a smaller transmission bandwidth is generally used to increase the power spectral density, while a lower code rate and a higher repetition count are used to further improve transmission accuracy. Therefore, the preamble length has a certain correlation with the data transmission bandwidth, code rate, and repetition count. These values ​​can be used to implicitly indicate the preamble length, thus saving the overhead of indicating the initial length.

[0019] In conjunction with the first or second aspect, in another possible implementation, the first length is A bits if at least one of the following third conditions is met: the transmission bandwidth of the first data is less than a first threshold; or, the number of repetitions of the first data is greater than a second threshold; or, the code rate of the first data is less than a third threshold; and the first length is B bits if at least one of the following fourth conditions is met: the transmission bandwidth of the first data is greater than or equal to the first threshold; or, the number of repetitions of the first data is less than or equal to the second threshold; or, the code rate of the first data is greater than or equal to the third threshold; wherein A is greater than B, and A and B are both positive integers.

[0020] This approach, due to the shorter preamble length (i.e., using a short sequence), is generally suitable for scenarios where A-IoT devices have a high SNR (Signal NR). In such cases, A-IoT devices typically use a higher code rate and a larger transmission bandwidth to transmit data. Conversely, when the SNR of A-IoT devices is low, to improve transmission accuracy, a smaller transmission bandwidth is generally used to increase the power spectral density, while a lower code rate and a higher repetition count are used to further improve transmission accuracy. Therefore, the preamble length has a certain correlation with the data transmission bandwidth, code rate, and repetition count. These values ​​can be used to implicitly indicate the preamble length, thus saving the overhead of indicating the initial length.

[0021] In conjunction with the first or second aspect, in yet another possible implementation, the first length is 32 bits or 8 bits.

[0022] In conjunction with the first or second aspect, in another possible implementation, the first preamble is a first sequence of length 8*N, which is the same as the sequence obtained by repeating the first base sequence N times, where N is a positive integer greater than or equal to 1, and the length of the first base sequence is 8; or, the first preamble is a second base sequence of length 8*N.

[0023] Using this method, A-IoT devices can store the first base sequence and generate a first sequence based on it during uplink transmission. Thus, both the reader and the A-IoT device only need to store the first base sequence, reducing storage requirements on both sides. When the reader receives the PDRCH, it can obtain the first sequence based on the first base sequence, enabling timing and synchronization based on this first sequence.

[0024] In another possible implementation, in conjunction with the first or second aspect, the PDRCH further includes a postcode, the length of which is the first length.

[0025] In conjunction with the first or second aspect, in yet another possible implementation, the PDRCH further includes a mid-prefix, the length of which is the first length.

[0026] In another possible implementation, in conjunction with the first or second aspect, the first information is carried in a downlink message.

[0027] In another possible implementation, in conjunction with the first or second aspect, when the number of repetitions M of the first data is greater than 1, the length of the first preamble is M times the first length, where M is a positive integer.

[0028] In conjunction with the first or second aspect, in another possible implementation, when the number of repetitions is greater than 1, the length of the first preamble is 16 bits or 64 bits.

[0029] Thirdly, a communication device is provided. The communication device can perform the methods described in any of the first to second aspects or any of the embodiments described in the first to second aspects. The communication device can be an A-IoT device or a reader / writer, or it can be a module (e.g., a chip) applied in an A-IoT device or a module (e.g., a chip) applied in a reader / writer.

[0030] In one possible implementation, the communication device includes a transceiver unit and a processing unit. The transceiver unit performs the receiving and / or transmitting operations in the methods of any one of the first to second aspects or any one of the first to second aspects described above; the processing unit performs the processing operations in the methods of any one of the first to second aspects or any one of the first to second aspects described above.

[0031] In another possible implementation, the communication device includes a processor coupled to a memory; the processor is configured to support the device in performing the corresponding functions in the channel state information reporting method described above. The memory, coupled to the processor, stores necessary computer programs (or computer-executable instructions) and / or data for the device. Optionally, the communication device may further include a communication interface for supporting communication between the device and other network elements, such as the transmission or reception of data and / or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface. Optionally, the memory may be located internally within the communication device and integrated with the processor; alternatively, it may be located externally to the communication device.

[0032] In another possible implementation, the communication device includes a processor and a transceiver, the processor being coupled to the transceiver. The processor executes computer programs or instructions to control the transceiver to receive and transmit information. When the processor executes the computer programs or instructions, it is also used to implement the above method through logic circuits or execution code instructions. The transceiver can be a transceiver circuit, a transceiver module, or an input / output interface, used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device. When the communication device is a chip, the transceiver is a transceiver circuit or an input / output interface.

[0033] When the communication device is a chip, the transmitting unit can be an output unit, such as an output circuit or a communication interface; the receiving unit can be an input unit, such as an input circuit or a communication interface. When the communication device is a terminal device, the transmitting unit can be a transmitter or a receiver; the receiving unit can be a receiver or a receiver.

[0034] Fourthly, a computer-readable storage medium is provided that stores a computer program or instructions thereon, which, when executed by a communication device, implement the method as described in the first aspect or any embodiment of the first aspect, or implement the method as described in the second aspect or any embodiment of the second aspect.

[0035] Fifthly, a computer program product is provided that, when executed on a communication device, implements the method as described in the first aspect or any embodiment of the first aspect, or implements the method as described in the second aspect or any embodiment of the second aspect.

[0036] A sixth aspect provides a communication system, including a first communication device and a second communication device, the first communication device being configured to implement the method as described in the first aspect or any embodiment of the first aspect, and the second communication device being configured to implement the method as described in the second aspect or any embodiment of the second aspect. Attached Figure Description

[0037] Figure 1 is a schematic diagram of the architecture of the communication system 1000 used in the embodiments of this application;

[0038] Figures 2a-2e are schematic diagrams of the network topology provided in the embodiments of this application;

[0039] Figure 3 is a schematic diagram of the working principle of RFID;

[0040] Figure 4 is a schematic diagram of the access process for A-IoT devices;

[0041] Figure 5 is a schematic diagram of the existing PDRCH format;

[0042] Figure 6 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0043] Figure 7 is a schematic diagram of the PDRCH format provided in the embodiments of this application;

[0044] Figure 8 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0045] Figures 9 and 10 are schematic diagrams of the communication device provided in the embodiments of this application. Detailed Implementation

[0046] The scheme of this application will be further described below with reference to the accompanying drawings.

[0047] The technical solutions provided in this application can be applied to various communication systems, such as 5G (5th generation mobile communication technology), future evolution systems, or multiple communication convergence systems, as well as existing communication systems. The application scenarios of the technical solutions provided in this application can include various scenarios, such as machine-to-machine (M2M), macro-micro communication, enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (uRLLC), and massive machine-type communication (mMTC). These scenarios may include, but are not limited to, communication scenarios between terminal devices, communication scenarios between network devices, and communication scenarios between network devices and terminal devices. Among these, network devices include access network devices and core network devices.

[0048] Figure 1 is a schematic diagram of the architecture of a communication system 1000 provided in an embodiment of this application. As shown in Figure 1, the communication system 1000 includes a radio access network (RAN) 100, wherein the RAN 100 includes at least one RAN node (110a and 110b in Figure 1, collectively referred to as 110), and may also include at least one terminal (120a-120j in Figure 1, collectively referred to as 120). The RAN 100 may also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1). The terminal 120 is wirelessly connected to the RAN node 110. Terminals and RAN nodes can be interconnected via wired or wireless means. The communication system 1000 may also include a core network 200. The RAN node 110 is connected to the core network 200 via wireless or wired means. The core network equipment in core network 200 and the RAN node 110 in RAN 100 can be independent and different physical devices, or they can be the same physical device that integrates the logical functions of the core network equipment and the logical functions of the RAN node. Communication system 1000 may also include Internet 300.

[0049] RAN100 can be an evolved universal terrestrial radio access (E-UTRA) system, a new radio (NR) system, or a future radio access system as defined in the 3rd generation partnership project (3GPP), or it can be a WiFi system. RAN100 can also include two or more of the above-mentioned different radio access systems. RAN100 can also be an open RAN (O-RAN).

[0050] RAN nodes, also known as radio access network devices, RAN entities, or access nodes, are used to help terminals access communication systems wirelessly. In one application scenario, an RAN node can be a base station, an evolved NodeB (eNodeB), a transmission and reception point (TRP), a next-generation NodeB (gNB) in a 5G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system. RAN nodes can be macro base stations (as shown in Figure 1, 110a), micro base stations or indoor stations (as shown in Figure 1, 110b), relay nodes, or donor nodes.

[0051] In another application scenario, multiple RAN nodes can collaborate to help terminals achieve wireless access, with different RAN nodes implementing different functions of the base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). Here, the CU performs the functions of the base station's Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP), and can also perform the functions of the Service Data Adaptation Protocol (SDAP). The DU performs the functions of the base station's Radio Link Control (RANC) and Medium Access Control (MAC) layers, and can also perform some or all of the physical layer functions. For specific descriptions of these protocol layers, refer to the relevant 3GPP technical specifications. The RU can be used to implement radio frequency signal transmission and reception. The CU and DU can be two independent RAN nodes or integrated into the same RAN node, such as within a baseband unit (BBU). The RU can be included in radio frequency equipment, such as in a remote radio unit (RRU) or an active antenna unit (AAU). The CU can be further divided into two types of RAN nodes: CU-control plane and CU-user plane.

[0052] In different systems, RAN nodes may have different names. For example, in an O-RAN system, a CU can be called an open CU (O-CU), a DU can be called an open DU (O-DU), and an RU can be called an open RU (O-RU). The RAN nodes in the embodiments of this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. For example, a RAN node can be a server loaded with the corresponding software modules. The embodiments of this application do not limit the specific technology or device form used in the RAN nodes. For ease of description, a base station is used as an example of a RAN node in the following description.

[0053] A terminal is a device with wireless transceiver capabilities, capable of sending signals to or receiving signals from a base station. Terminals can also be called terminal equipment, user equipment (UE), mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the specific technology or device form used in the terminal.

[0054] Base stations and terminals can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the base stations and terminals.

[0055] The roles of base stations and terminals can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile base station. For terminals 120j that access the wireless access network 100 through 120i, terminal 120i is a base station; however, for base station 110a, 120i is a terminal, meaning that 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a base station-to-base station interface protocol. In this case, relative to 110a, 120i is also a base station. Therefore, both base stations and terminals can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be called communication devices with base station functions, and 120a-120j in Figure 1 can be called communication devices with terminal functions.

[0056] Communication between base stations and terminals, between base stations, and between terminals can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can be conducted using spectrum below 6 GHz, spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used for wireless communication.

[0057] In the embodiments of this application, the functions of the base station can be executed by modules (such as chips) within the base station, or by a control subsystem that includes base station functions. This control subsystem, including base station functions, can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities. Similarly, the functions of the terminal can be executed by modules (such as chips or modems) within the terminal, or by a device that includes terminal functions.

[0058] In this application, the base station sends downlink signals or downlink information to the terminal, with the downlink information carried on the downlink channel; the terminal sends uplink signals or uplink information to the base station, with the uplink information carried on the uplink channel. To communicate with the base station, the terminal needs to establish a radio connection on a cell controlled by the base station. The cell with which the terminal has established a radio connection is called the terminal's serving cell. When the terminal communicates with this serving cell, it is also susceptible to interference from signals from neighboring cells.

[0059] The massive demand for IoT will pose new challenges to the deployment and maintenance costs of IoT. For example, the price of existing narrowband IoT (NB-IoT) modules ranges from tens to hundreds of RMB, resulting in high costs for large-scale deployment. Furthermore, subsequent maintenance, such as battery replacement, also incurs high operating costs. Extreme scenarios requiring battery-free power, such as those involving low temperatures, high humidity, high pressure, and high radiation, or everyday applications like implantable healthcare and logistics warehousing, place high demands on the cost reduction and passive nature of IoT terminals. However, current wireless communication technologies used in IoT systems, such as Bluetooth, ZigBee, NB-IoT, and LoRa, have high power consumption requirements and cannot obtain sufficient energy from the surrounding environment, leading to high deployment and maintenance costs, making them unsuitable for passive IoT applications. Passive IoT technology, with its advantages of low cost, ultra-low power consumption, and ease of deployment, can further expand IoT applications and provide billions of connections, attracting widespread attention in recent years.

[0060] I. Ambient Internet of Things (A-IoT):

[0061] Passive IoT technology refers to IoT without a "source," where "source" refers to a power source. Currently, the most common and mature passive IoT technology is radio frequency identification (RFID), which uses radio frequency to read and write data to recording media (electronic tags or RFID cards). The basic principle of RFID is to use backscattering to complete energy conversion and communication. An RFID system generally includes a reader and an RFID tag. The reader transmits electromagnetic waves of a certain frequency through its antenna; when the RFID tag enters the working range of the transmitting antenna, it is activated by an induced current, and then transmits its stored information through its internal antenna; the transmission process involves load modulation of the received electromagnetic waves. The reader's antenna receives the carrier signal from the RFID tag and transmits it back to the reader.

[0062] Traditional RFID has several drawbacks, such as short transmission distance and a limited reading range of only a few meters. It typically requires handheld scanning, leading to labor-intensive and time-consuming operations. Furthermore, the lack of interference management solutions results in severe interference and capacity issues between RFID readers, especially in densely deployed scenarios, making it difficult for RFID to support seamless, large-scale networks.

[0063] Therefore, A-IoT was proposed to support backscatter communication technology in cellular systems.

[0064] A-IoT, also known as passive IoT, offers lower power consumption and lower cost compared to NB-IoT within the 3GPP standard framework. In non-3GPP frameworks, A-IoT targets the market demand for RFID, providing comparable and even more advantageous technical solutions.

[0065] The demand for A-IoT stems from addressing scenarios not covered by current 3GPP technologies, such as the following three scenarios:

[0066] 1) Under extreme environmental conditions, such as high pressure, extremely high / low temperature, and humid environments.

[0067] 2) Scenarios such as ultra-low complexity, very small device size / shape factor (e.g., thickness in millimeters), maintenance-free (e.g., traditional batteries that do not require device replacement) and longer life cycle.

[0068] 3) Device scenarios where traditional battery-powered devices are not applicable.

[0069] A-IoT can provide Internet of Things (IoT) services and features characteristics such as battery-free operation, low power consumption, low complexity, low cost, small size, and long lifespan. Compared to traditional IoT technologies, an A-IoT system includes A-IoT devices and readers. For example, a reader can also be called an interrogator. For example, an A-IoT device can also be called an A-IoT terminal, A-IoT, or a device with A-IoT functionality identified by a tag.

[0070] A-IoT devices are powered by energy harvesting, allowing them to operate without batteries or with limited energy storage (i.e., using capacitors). They can communicate with other devices without traditional power sources or avoid human intervention for charging or replacement. A-IoT devices can harvest energy from radio waves or, in specific use cases, from any other form of energy. For example, in some scenarios, A-IoT devices can harvest energy from radio waves, which may originate from 5G New Radio (NR) network entities or UEs. In other scenarios, A-IoT devices can harvest energy from solar energy, light, motion / vibration, heat, pressure, or any other source.

[0071] II. Device types of A-IoT devices:

[0072] In one possible example, an A-IoT device can have the following two characteristics:

[0073] A-IoT device 1 has a peak power consumption of around 1 microwatt, energy storage capabilities, and a sampling clock frequency offset (SFO) of up to 10. X ppm, without signal amplification capability, where ppm represents parts per million. Device-to-reader (D2R) transmission of A-IoT device 1 is based on backscatter transmission using a carrier frequency provided externally. D2R refers to the transmission process from the A-IoT device to the reader (such as a network device or terminal device), which is described in detail below.

[0074] A-IoT device 2, with peak power consumption in the hundreds of microwatts, has energy storage capabilities and an SFO of up to 10. Xppm indicates signal amplification capability. Furthermore, based on the source of the carrier frequency used for transmission, A-IoT device 2 can be divided into A-IoT device 2a and A-IoT device 2b. Specifically, A-IoT device 2a's D2R transmission is based on backscatter transmission using an externally provided carrier frequency, while A-IoT device 2b's D2R transmission is based on a carrier frequency generated internally within the device.

[0075] III. Network Topology of A-IoT:

[0076] 3GPP defines several A-IoT topologies, as shown in Figures 2a-2e.

[0077] Network Topology 1: Interaction between Network Devices and A-IoT Devices

[0078] Please refer to Figure 2a, which is a schematic diagram of a topology provided in an embodiment of this application. In Figure 2a, the A-IoT device and the network device communicate bidirectionally. The network device can send a reader-to-device (R2D) signal to the A-IoT device; the A-IoT device receives the R2D signal sent from the network device; optionally, the A-IoT device sends a corresponding response signal to the network device (this response signal can be a backscattered signal). Correspondingly, the A-IoT device can send a D2R signal to the network device; the network device receives the D2R signal from the A-IoT device; optionally, the network device sends a corresponding response signal to the A-IoT device.

[0079] It should be noted that, in Figure 2a, the transmission from the network device to the A-IoT device can be referred to as "R2D" transmission, and the transmission from the A-IoT device to the network device can be referred to as "D2R" transmission. Optionally, in Figure 2a, the reader / writer can be a network device.

[0080] In some possible implementations, a network device is a device with wireless transceiver capabilities. In some implementations, the network device may be responsible for air interface-side radio resource management (RRM), quality of service (QoS) management, data compression and encryption, and data transmission and reception.

[0081] In some possible implementations, network devices may include base stations (BS) in a communication system or devices deployed in a radio access network (RAN) to provide wireless communication functions; that is, network devices may include devices in the RAN. For example, devices in the RAN may include evolved node B (eNB or eNodeB) in an LTE communication system, next-generation evolved node B (ng-eNB) in an NR communication system, next-generation node B (gNB) in an NR communication system, master node (MN) in a dual-connectivity architecture, secondary node (SN) in a dual-connectivity architecture, etc., without specific limitations.

[0082] In some possible implementations, network devices may include devices in the core network (CN). For example, devices in the CN may include access and mobility management functions (AMF), user plane functions (UPF), session management functions (SMF), etc.

[0083] In some possible implementations, network devices can also be access points (APs) in Wireless Local Area Networks (WLANs), relay stations, communication devices in future evolved PLMN networks, and communication devices in Non-Terrestrial Networks (NTNs).

[0084] In some possible implementations, the network device may include means for providing wireless communication capabilities to terminal devices, such as a chip system, a chip, or a chip module. For example, the chip system may include a chip, or it may include other discrete devices.

[0085] In some possible implementations, network devices can communicate with Internet Protocol (IP) networks, such as the Internet, private IP networks, or other data networks.

[0086] In some possible implementations, the network device may include a single node to perform the functions of the aforementioned base station, or it may include two or more independent nodes to perform the functions of the aforementioned base station. For example, the network device includes centralized units (CUs) and distributed units (DUs), such as gNB-CU and gNB-DU.

[0087] In some possible implementations, the network device can be any of the multiple sites that perform coherent joint transmission (CJT) with the terminal device, or other sites outside of the multiple sites, or other network devices that communicate with the terminal device, without any specific restrictions.

[0088] In some possible implementations, the network device can have mobility characteristics; for example, the network device can be a mobile device. Optionally, the network device can be a satellite or a balloon station. For example, the satellite can be a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a geostationary Earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network device can also be a base station located on land, water, or other similar locations.

[0089] In some possible implementations, network devices can provide services to a cell, and terminal devices within that cell can communicate with the network devices via transmission resources (such as spectrum resources). This cell can be a macro cell, small cell, metro cell, micro cell, pico cell, or femto cell, etc.

[0090] In some possible implementations, the network device described in the embodiments of this application may be a chip, chip module, device, unit, etc., and there are no specific limitations on it.

[0091] Network Topology 2: Network devices interact with A-IoT devices through intermediate nodes:

[0092] Please refer to Figure 2b, which is a schematic diagram of another topology provided in an embodiment of this application. In Figure 2b, since the network device and the A-IoT device cannot communicate directly, the intermediate node can relay the communication between the network device and the A-IoT device. In Figure 2b, the transmission from the intermediate node to the A-IoT device can be called "R2D" transmission, and the transmission from the A-IoT device to the intermediate node can be called "D2R" transmission. In Figure 2b, optionally, the reader / writer can refer to the intermediate node.

[0093] Specifically, the network device sends R2D data to the intermediate node. The intermediate node then assembles the R2D data into an R2D signal and sends it directly to the A-IoT device, or processes the R2D data to assemble an R2D signal before sending it to the A-IoT device. The R2D data can be the data portion of the R2D signal. Correspondingly, the A-IoT device receives the R2D signal. Optionally, the A-IoT device sends a corresponding response signal to the intermediate node (this response signal can be a backscattered signal). Optionally, the intermediate node forwards the response signal to the network device, or processes the response signal before sending it to the network device. The network device and the intermediate node can communicate via the Uu interface. The A-IoT device sends a D2R signal to the intermediate node. The intermediate node then forwards the D2R data from the signal to the network device, or processes the D2R data before sending it to the network device. Correspondingly, the network device receives the D2R data, which can be the data portion of the D2R signal. Optionally, the network device sends a corresponding response signal to the intermediate node. Alternatively, the intermediate node forwards the response signal to the A-IoT device, or processes the response signal before sending it to the A-IoT device. The network device and the intermediate node can communicate via a Uu interface.

[0094] In some possible implementations, an intermediate node is a device with wireless transceiver capabilities. For example, an intermediate node could be a terminal device. For example, intermediate nodes can be eNBs, eNodeBs, gNodeBs, gNBs, multi-transmission receiving points (M-TRPs), base stations in subsequent evolution systems, access nodes in WLAN systems, mobile phones, terminals, remote UEs, relay UEs, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), tablets, computers with wireless transceiver capabilities, virtual reality (VR) devices, augmented reality (AR) devices, wireless devices in industrial control, wireless devices in autonomous driving, wireless devices in remote medical care, wireless devices in smart grids, wireless devices in transportation safety, wireless devices in smart cities, and wireless devices in smart homes. Wireless devices in the home, in-vehicle devices, wearable devices, or terminal devices in future public land mobile networks (PLMNs), etc.

[0095] For a detailed description of the network equipment, please refer to Figure 2a; it will not be repeated here.

[0096] Network Topology 3: Interaction between network devices and auxiliary nodes, A-IoT devices:

[0097] “Network Topology 3” is divided into R2D-assisted network topology and D2R-assisted network topology.

[0098] Please refer to Figure 2c. The topology in Figure 2c can be called an R2D-assisted network topology, which is another topology diagram provided in the embodiments of this application. In the R2D-assisted network topology, network devices cannot directly send R2D signals to A-IoT devices, while A-IoT devices can directly send D2R signals to network devices and receive R2D signals from the auxiliary node. Optionally, for R2D, the reader / writer can be an auxiliary node; for D2R, the reader / writer can be a network device.

[0099] Specifically, the network device sends R2D data to the auxiliary node; then, the auxiliary node can either assemble the R2D data into an R2D signal and directly forward it to the A-IoT device, or process the R2D data to assemble an R2D signal before sending it to the A-IoT device. The R2D data can be the data portion of the R2D signal. Correspondingly, the A-IoT device receives the R2D signal from the auxiliary node. The A-IoT device can also directly send D2R signals to the network device. The network device and the auxiliary node can communicate via the Uu interface.

[0100] In Figure 2c, the transmission from the auxiliary node to the A-IoT device can be called "R2D" transmission, and the transmission from the A-IoT device to the network device can be called "D2R" transmission.

[0101] Please refer to Figure 2d. The topology in Figure 2d can be called a D2R-assisted network topology, which is another topology diagram provided in the embodiments of this application. In the D2R-assisted network topology, A-IoT devices cannot directly send D2R signals to network devices, but A-IoT devices can receive R2D signals from network devices and then send D2R signals to the auxiliary node. Optionally, for R2D, the reader / writer can be a network device; for D2R, the reader / writer can be an auxiliary node.

[0102] Specifically, network devices can send R2D signals to A-IoT devices. Correspondingly, after receiving the R2D signal from the network device, the A-IoT device can optionally send a D2R signal to the auxiliary node. The auxiliary node then forwards the D2R data from the D2R signal to the network device, or processes the D2R data in the D2R signal before sending it to the network device. The D2R data can be the data portion of the D2R signal. The network device and the auxiliary node can communicate via the Uu interface.

[0103] In Figure 2d, the transmission from the network device to the A-IoT device can be called "R2D" transmission, and the transmission from the A-IoT device to the auxiliary node can be called "D2R" transmission.

[0104] In some possible implementations, an auxiliary node is a device with wireless transceiver capabilities. For example, an auxiliary node can be an eNB, eNodeB, gNodeB, gNB, M-TRP, a base station in a subsequent evolution system, an access node in a WLAN system, a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a VR terminal, an AR terminal, a wireless terminal in industrial control, a vehicle terminal, a wireless terminal in autonomous driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a wearable terminal, etc.

[0105] Network Topology 4: Interaction between Terminal Devices and A-IoT Devices

[0106] Please refer to Figure 2e, which is a schematic diagram of another topology provided in an embodiment of this application. In Figure 2e, the A-IoT device and the terminal device communicate directly in both directions. The reader / writer can refer to the terminal device.

[0107] Specifically, the terminal device sends an R2D signal to the A-IoT device, and the A-IoT device receives the R2D signal sent by the terminal device. Optionally, the A-IoT device sends a corresponding response signal to the terminal device. Correspondingly, the A-IoT device sends a D2R signal to the terminal device; the terminal device receives the D2R signal sent by the A-IoT device, and optionally, the terminal device sends a corresponding response signal to the A-IoT device (this response signal can be a backscattered signal).

[0108] In this application embodiment, the terminal device is a device with wireless transceiver capabilities, which may be referred to as a terminal, user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, vehicle-mounted terminal, industrial control terminal, UE unit, UE station, mobile station, remote station, remote terminal, mobile device, wireless communication device, UE agent, or UE device, etc. The terminal device can be fixed or mobile. It should be noted that the terminal device can support at least one wireless communication technology, such as Long Term Evolution (LTE) or New Radio (NR). For example, terminal devices can be mobile phones, tablets, desktop computers, laptops, all-in-one computers, in-vehicle terminals, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, and session initiation protocols.

[0109] (Session Initiation Protocol, SIP) telephones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, wearable devices, terminal devices in future mobile communication networks, or terminal devices in future evolved public land mobile networks (PLMNs), etc. In some embodiments of this application, the terminal device may also be a transceiver device, such as a chip system. The chip system may include chips and other discrete components.

[0110] In the above description, "direct" means that the signal transmission does not pass through auxiliary nodes or intermediate nodes. However, in actual transmission, it may need to pass through other devices, such as routers in the communication link.

[0111] In summary, in this embodiment of the application, the A-IoT system may include network nodes and A-IoT devices. The network node may be one of the network devices, intermediate nodes, or auxiliary nodes shown in Figures 2a to 2e. The intermediate or auxiliary node plays a relay role in the transmission process between the network device and the A-IoT device.

[0112] IV. D2R / R2D Transmission:

[0113] In this embodiment, the communication between the reader / writer and the A-IoT device is referred to as R2D, which can also be called R2D transmission, R2D communication, R2D signal transmission, or R2D information transmission. Optionally, the R2D signal can also be called the A-IoT R2D signal, and the data portion therein can be called R2D data or A-IoT R2D data. This embodiment does not impose any limitations on this.

[0114] Communication between A-IoT devices and readers is referred to as D2R, or D2R transmission, D2R communication, D2R signal transmission, or D2R information transmission. Optionally, the D2R signal can be called an A-IoT D2R signal, and the data portion can be called D2R data or A-IoT D2R data; this application does not limit the specific terminology used in the embodiments.

[0115] Optionally, the signal transmission between the reader and the A-IoT device can be D2R and / or R2D for any of the above network topologies, and this application does not impose any restrictions.

[0116] For the network topology shown in Figure 2a, R2D signal transmission refers to the network device directly sending R2D signals to the A-IoT device, and the A-IoT device directly receiving R2D signals from the network device. D2R signal transmission refers to the A-IoT device directly sending D2R signals to the network device, and the network device directly receiving D2R signals from the A-IoT device.

[0117] For the network topology shown in Figure 2b, R2D signal transmission refers to the network device sending R2D data to the intermediate node, the intermediate node assembling the R2D data into an R2D signal and sending it to the A-IoT device, and the A-IoT device receiving the R2D signal from the intermediate node. D2R signal transmission refers to the A-IoT device sending a D2R signal to the intermediate node, the intermediate node forwarding the D2R data in the D2R signal to the network device, and the network device receiving the D2R data from the intermediate node.

[0118] For the network topology shown in Figure 2c, R2D signal transmission refers to the network device sending R2D data to the auxiliary node, the auxiliary node assembling the R2D data into an R2D signal and sending it to the A-IoT device, and the A-IoT device receiving the R2D signal from the auxiliary node. D2R signal transmission refers to the A-IoT device sending a D2R signal to the network device, and the network device receiving the D2R signal from the A-IoT device.

[0119] For the network topology shown in Figure 2d, R2D signal transmission refers to the network device directly sending R2D signals to the A-IoT device, and the A-IoT device directly receiving R2D signals from the network device. D2R signal transmission refers to the A-IoT device sending D2R signals to the auxiliary node, the auxiliary node forwarding the D2R data in the D2R signal to the network device, and the network device receiving the D2R data from the auxiliary node.

[0120] For the network topology shown in Figure 2e, R2D signal transmission refers to the terminal device directly sending R2D signals to the A-IoT device, and the A-IoT device directly receiving R2D signals from the terminal device. D2R signal transmission refers to the A-IoT device directly sending D2R signals to the terminal device, and the terminal device directly receiving D2R signals from the A-IoT device.

[0121] In the above description, "direct" means that the signal transmission does not pass through auxiliary nodes or intermediate nodes. However, in actual transmission, it may need to pass through other devices, such as routers in the communication link.

[0122] With the increasing prevalence of machine-type communication (MTC) and Internet of Things (IoT) communication in 5G NR, the number of connected IoT devices is growing daily. Therefore, the industry's demand for reduced cost and power consumption in IoT devices is becoming increasingly strong. During the 4G era, the 3rd Generation Partnership Project (3GPP) introduced narrowband IoT (NB-IoT) systems. However, NB-IoT terminals still require external power (batteries) and have the ability to generate local high-frequency carrier waves, thus limiting their power consumption to milliwatts. But with the evolution and development of 5G IoT, the need for lower-power terminals in 5G networks is growing. Radio frequency identification (RFID) technology provides a good technical reference for low power consumption, supporting microwatt-level power consumption. RFID terminals (tags) use low-precision, low-power mid-to-low frequency ring oscillators or receive downlink signals without a local oscillator. When the tag is working, the energy and carrier wave for communication are supplied by the reader. Communication is based on the reflected carrier wave, as shown in Figure 3, which is a schematic diagram of the working principle of RFID. The solid line is the carrier wave sent by the reader, and the dashed line represents the tag modulating and reflecting the carrier wave sent by the reader for transmission.

[0123] Given the low power consumption advantages of RFID communication technology, ambient IoT (A-IoT) has emerged in the 5G environment. To meet ultra-low power consumption requirements, A-IoT devices also use low-precision, low-power mid-to-low frequency ring oscillators or receivers without a local oscillator to receive downlink signals. This receiving method further reduces the downlink power consumption of A-IoT devices. However, for this type of low-power receiving method, only amplitude detection, such as envelope detection, can be performed because a low-precision ring oscillator alone cannot guarantee accurate demodulation of signal phase information.

[0124] AIoT devices are low-cost, with typical power consumption of approximately 1µW and sampling clock frequency accuracy of less than 10^5ppm, making them suitable only for asynchronous transmission mechanisms. A-IoT device access is achieved through random access using a time-slot-based Aloha asynchronous access method. Successfully connected A-IoT devices can then transmit data, such as sending electronic product codes (EPCs). Figure 4 illustrates the A-IoT device access process, which includes the following steps:

[0125] S401 / S402. The reader identifies the selected A-IoT device or group of A-IoT devices and then sends a paging message (or trigger message) to initiate the random access procedure. Optionally, the paging message is sent in a broadcast manner, meaning that all A-IoT devices within the reader's coverage area can receive the paging message.

[0126] In some implementations, the paging message may be a query command, a query repeat command, a query adjust command, etc., and this application embodiment does not impose any restrictions.

[0127] In some implementations, the paging message includes resource allocation information, which may include time-domain resource allocation information. This time-domain resource allocation information indicates time-domain resources, which are available time slots in the time domain. For example, the time-domain resource allocation information includes a Q value, and the time-domain resources indicated by the time-domain resource allocation information include time slot 0 to time slot (2). Q -1), where i in time slot i can be considered as the index of the time slot (also called the identifier or time slot value), and i takes a value greater than or equal to 0 and less than or equal to 2. Q An integer equal to -1. The A-IoT device selects a time slot from the aforementioned time-domain resources and uses the index of that time slot as the initial value of the time slot counter.

[0128] Optionally, the paging message may also include the identification information of the A-IoT device or the identification information of the A-IoT device group. Upon receiving the paging message, if the identification information of the A-IoT device or the identification information of the A-IoT device group to which the A-IoT device belongs matches the identification information of the A-IoT device or the A-IoT device group in the paging message, then the A-IoT device will consider itself to be participating in this random access process.

[0129] In some implementations, after each time an A-IoT device receives the aforementioned paging message, it decrements the value of its time slot counter by 1 until the value of its time slot counter reaches 0. At this point, it can obtain a random access procedure transmission opportunity (it has preempted the time slot), and the A-IoT device will perform the random access procedure within that time slot.

[0130] It should be noted that step S401 is an optional step, indicated by a dashed line in Figure 4. That is, the reader can execute step S401 to send a paging message to the A-IoT device, and the A-IoT device will initiate a random access procedure after receiving the paging message; or, the reader can skip step S401, and the A-IoT device can directly initiate a random access procedure.

[0131] The random access procedure described above can be a contention-based four-step random access, a contention-based two-step random access, or a non-contention-based random access; no restrictions are imposed in this embodiment.

[0132] For example, this application uses a contention-based four-step random access method as an example to briefly describe the specific process.

[0133] Referring to Figure 4, steps S403-S406 are the random access procedures initiated by the A-IoT device in this embodiment of the application.

[0134] In some implementations, the above contention-based four-step random access procedure includes:

[0135] S403.A-IoT devices preempt time slots and send the first message in the preempted time slot.

[0136] Optionally, the aforementioned first message may also be referred to as the first message, message 1, Msg1, etc., and this application embodiment does not limit it in this way.

[0137] The A-IoT device sends a first message, and the reader receives the first message accordingly. The first message includes a random number identifier, which is used to identify the A-IoT device.

[0138] Optionally, the random number identifier can be randomly generated by the A-IoT device or generated based on the identification information of the A-IoT device. For example, it can be obtained by processing the truncated device identifier corresponding to the A-IoT device. This processing can be, for example, hash processing or other possible processing methods, which are not limited in this embodiment.

[0139] In some implementations, the length of the random number identifier can be set according to actual needs, such as 16 bits, 24 bits, etc. Optionally, the random number identifier can be a 16-bit random number, denoted as RN16. The A-IoT device sends RN16 to the reader by sending a first message for access to the reader.

[0140] In some implementations, the purpose of the A-IoT device sending RN16 is to enable the reader to quickly detect whether an RN16 collision has occurred. If so, a new round of inventory processing is restarted. Since RN16 is only 16 bits, much smaller than the size of the A-IoT device identifier (which, for example, includes 96 bits), sending the A-IoT device identifier consumes significant resources in the first message. The reader only learns of a collision after receiving the 96-bit A-IoT device identifier, resulting in substantial resource waste. However, by including RN16 in the first message, the reader can quickly detect whether other A-IoT devices are sending the same RN16, thus determining whether a collision exists.

[0141] S404. The reader sends the second message.

[0142] In some implementations, if the reader receives the first message and successfully obtains the random number identifier in the first message, the reader will send a second message (e.g., an acknowledge character (ACK) message) to the A-IoT device.

[0143] Optionally, the second message may also be referred to as the second message, message 2, Msg2, etc., and this application embodiment does not limit it in this way.

[0144] The second message includes the random number identifier of the A-IoT device and is used to respond to the first message.

[0145] In some implementations, the second message is used for conflict resolution during the random access process. Specifically, if the A-IoT device receives the second message, and the second message carries the random number identifier sent by the A-IoT device, the A-IoT device considers its access to the reader / writer to be successful, and the A-IoT device will send a third message to the reader / writer.

[0146] S405.A-IoT devices send third messages.

[0147] Optionally, the aforementioned third message may also be referred to as the third message, message 3, Msg3, etc., and this application embodiment does not limit it in this way.

[0148] The aforementioned third message includes the identification information of the A-IoT device. This identification information can be a permanent identifier or a temporary identifier. A permanent identifier can be, for example, the EPC of the A-IoT device. This application embodiment does not limit this.

[0149] S406. The reader sends the fourth message.

[0150] Optionally, the fourth message may also be referred to as the fourth message, message 4, Msg4, etc., and this application embodiment does not limit it in this way.

[0151] It should be noted that the step of the reader sending the fourth message is optional, and is represented by a dashed line in Figure 4. After receiving the third message, the reader can send a fourth message to provide an ACK or to continue data transmission. The fourth message is used to respond to the third message and confirm whether the third message was successfully transmitted.

[0152] Figure 5 shows a schematic diagram of the existing PDRCH format. Since both uplink and downlink transmissions of A-IoT devices are based on an asynchronous mechanism, the A-IoT device adds a preamble to the data signal each time it transmits uplink. The reader detects the preamble to determine the start of the transmission.

[0153] The detection method involves the reader receiving a signal within the time window when the preamble is likely to arrive, and then performing a sliding correlation between the local preamble signal and the received signal. The position with the largest correlation value is determined as the timing position of the preamble.

[0154] However, current uplink data transmission uses a fixed-length preamble. The receiver uses this preamble for frame synchronization. When the uplink communication distance is long and the received signal's SNR is too low, if the preamble length is too short, the receiver will be unable to complete frame synchronization; while when the SNR of A-IoT devices is high, using a longer preamble will result in greater signaling overhead.

[0155] Therefore, how to design a preamble that reduces the overhead of the synchronization signal while ensuring uplink synchronization performance is an urgent problem to be solved.

[0156] To this end, this application provides a communication scheme in which the reader / writer indicates the first length of the first preamble and performs uplink synchronization based on the first length to receive the first data, thereby enabling flexible indication of the preamble length and reducing the overhead of the synchronization signal while ensuring uplink synchronization performance.

[0157] Figure 6 shows a flowchart of a communication method provided in an embodiment of this application. Exemplarily, the method may include the following steps:

[0158] S601. The reader sends the first information to the A-IoT device.

[0159] In this embodiment, since the uplink and downlink transmissions of the A-IoT device are based on an asynchronous mechanism, the A-IoT device adds a preamble to the data signal during each uplink transmission. Furthermore, because the communication environment for each uplink transmission / period may change, when the uplink communication distance is long and the received signal's SNR is too low, a preamble that is too short will prevent the receiver from completing frame synchronization. Conversely, when the A-IoT device's SNR is high, using a longer preamble will result in higher signaling overhead. Therefore, before the A-IoT device transmits uplink data, the reader sends first information to the A-IoT device, which indicates the first length of the first preamble, allowing for flexible adjustment of the preamble length. For example, based on the A-IoT device's SNR, the reader instructs a shorter preamble for A-IoT devices with higher received SNR. In this case, because the A-IoT device has a higher SNR, a shorter preamble can still achieve higher timing performance, and the preamble overhead is relatively reduced compared to a longer preamble.

[0160] For example, the first information is carried in a downlink message.

[0161] The first information is used to indicate the first length of the first preamble, and can be implemented in at least three ways:

[0162] In the first implementation, each preamble length corresponds to an index, and the A-IoT device and reader can pre-store the correspondence between the length of at least one preamble and at least one index. This first information includes a first index, which corresponds to a first length; that is, the length of the preamble is communicated to the A-IoT device through an index indicating the length of the preamble.

[0163] Table 1 below illustrates the correspondence between the length and index of two types of preambles:

[0164] Table 1

[0165] The first information can be 1 bit. When the first information is "0", it indicates that the first length of the first preamble is 32 bits. When the first information is "1", it indicates that the first length of the first preamble is 8 bits.

[0166] Alternatively, when the first information is "1", it indicates that the first length of the first preamble is 32 bits; when the first information is "0", it indicates that the first length of the first preamble is 8 bits.

[0167] Alternatively, this first information can also be a default value, which defaults to a conventional length, such as 32 bits.

[0168] In the second implementation, the first information directly indicates the first length of the first preamble, such as indicating that the first length is 8 bits or 32 bits.

[0169] The third implementation method is that the first information is used to configure the transmission parameters of the first data, and the transmission parameters correspond to the first length.

[0170] The transmission parameters of the first data include at least one of the following: the transmission bandwidth of the first data, the number of repetitions of the first data, and the bit rate of the first data.

[0171] Because preambles are relatively short (i.e., short sequences are used), they are generally suitable for scenarios where A-IoT devices have a high SNR (Signal NR). In such cases, A-IoT devices typically use a higher code rate and a larger transmission bandwidth to transmit data. Conversely, when the SNR of A-IoT devices is low, to improve transmission accuracy, a smaller transmission bandwidth is generally used to increase the power spectral density, while a lower code rate and a higher repetition count are used to further improve transmission accuracy. Therefore, the length of the preamble has a certain correlation with the data transmission bandwidth, code rate, and repetition count. These values ​​can be used to implicitly indicate the length of the preamble, thus saving the overhead of indicating the initial length.

[0172] In one example, the first length is A bits if at least one of the following first conditions is met:

[0173] The transmission bandwidth of the first data is less than or equal to a first threshold; or,

[0174] The number of repetitions of the first data is greater than or equal to the second threshold; or,

[0175] The bitrate of the first data is less than or equal to the third threshold.

[0176] The first condition includes at least one of the following: the transmission bandwidth of the first data is less than or equal to a first threshold, the number of repetitions of the first data is greater than or equal to a second threshold, and the code rate of the first data is less than or equal to a third threshold. When the SNR of an A-IoT device is low, in order to improve the transmission accuracy, a smaller transmission bandwidth is generally used to transmit data to increase the power spectral density, while a lower code rate and a higher number of repetitions are used to transmit data to improve the transmission accuracy. In this case, the length of the first preamble can be designed to be relatively long.

[0177] The first length is B bits if at least one of the following second conditions is met:

[0178] The transmission bandwidth of the first data is greater than a first threshold; or,

[0179] The number of repetitions of the first data is less than the second threshold; or,

[0180] The bitrate of the first data is greater than the third threshold.

[0181] The second condition includes at least one of the following: the transmission bandwidth of the first data is greater than a first threshold, the number of repetitions of the first data is less than a second threshold, and the code rate of the first data is greater than a third threshold. When the SNR of an A-IoT device is high, the A-IoT device will generally use a higher code rate and a larger transmission bandwidth to transmit data, and a lower number of repetitions. In this case, the length of the first preamble can be designed to be shorter.

[0182] In yet another example, the first length is A bits if at least one of the following third conditions is met:

[0183] The transmission bandwidth of the first data is less than a first threshold; or,

[0184] The number of repetitions of the first data is greater than the second threshold; or,

[0185] The bitrate of the first data is less than the third threshold.

[0186] The third condition includes at least one of the following: the transmission bandwidth of the first data is less than the first threshold, the number of repetitions of the first data is greater than the second threshold, and the code rate of the first data is less than the third threshold. When the SNR of an A-IoT device is low, in order to improve the transmission accuracy, a smaller transmission bandwidth is generally used to transmit data to increase the power spectral density, while a lower code rate and a higher number of repetitions are used to transmit data to improve the transmission accuracy. In this case, the length of the first preamble can be designed to be relatively long.

[0187] The first length is B bits if at least one of the following fourth conditions is met:

[0188] The transmission bandwidth of the first data is greater than or equal to a first threshold; or,

[0189] The number of repetitions of the first data is less than or equal to the second threshold; or,

[0190] The bitrate of the first data is greater than or equal to the third threshold.

[0191] The fourth condition includes at least one of the following: the transmission bandwidth of the first data is greater than or equal to the first threshold; the number of repetitions of the first data is less than or equal to the second threshold; and the code rate of the first data is greater than or equal to the third threshold. When the SNR of an A-IoT device is high, the A-IoT device will generally use a higher code rate and a larger transmission bandwidth to transmit data, and a lower number of repetitions. In this case, the length of the first preamble can be designed to be shorter.

[0192] Where A is greater than B, and A and B are both positive integers.

[0193] For example, considering the overhead of indication and the performance of positioning and synchronization, the first length is 32 bits or 8 bits.

[0194] The format of the first preamble can be implemented in at least two ways:

[0195] In the first implementation, the first preamble is a first sequence of length 8*N. This first sequence is identical to the first base sequence obtained by repeating it N times, where N is a positive integer greater than or equal to 1, and the length of the first base sequence is 8. The A-IoT device can store this first base sequence and generate the first sequence based on it during uplink transmission. Therefore, the reader and the A-IoT device only need to store this first base sequence, reducing the storage requirements on both sides. When the reader receives the PDRCH, it can obtain the first sequence based on the first base sequence, and then perform timing and synchronization based on this first sequence. For example, the first base sequence can be a sequence with good timing performance, such as an m-sequence or a golay sequence; this application does not limit this.

[0196] The second implementation method involves using an 8*N second base sequence as the first preamble. This implementation method allows for flexible definition of the second base sequence.

[0197] The third implementation involves the following: when the number of repetitions M of the first data is greater than 1, the length of the first preamble is M times the first length, where M is a positive integer. If the number of repetitions is 1, the length of the first preamble is either the first sequence A or B; if the number of repetitions is greater than 1, the first preamble is a repetition of M base sequences. For example, if M = 2 and the base sequence is A, then the final sequence is [A, A]. For instance, when the number of repetitions of the first data is greater than 1, the length of the first preamble is 16 bits or 64 bits.

[0198] The S602.A-IoT device sends a PDRCH to the reader.

[0199] After receiving the aforementioned first information, the A-IoT device can determine the first length of the first preamble and send a PDRCH to the reader. The PDRCH includes the first preamble and first data, with the first preamble preceding the first data. The first preamble is used for synchronization of the first data, allowing the reader to determine the start of the first data transmission. Synchronization refers to timing, synchronization, etc. The length of the first preamble is the first length indicated by the aforementioned first information.

[0200] Figure 7 shows a schematic diagram of the PDRCH format provided in an embodiment of this application. The PDRCH includes a preamble and data. The preamble is located before the data and is used for data synchronization and for the reader to determine the start of data transmission. The length of the preamble can be indicated by the first information mentioned above.

[0201] Furthermore, the PDRCH may also include a postcode. For example, the length of the postcode may be the same as the length of the precode described above, i.e., both are of the first length.

[0202] Furthermore, in scenarios where large amounts of data need to be transmitted in segments, the communication environment may change during segmentation. Therefore, the PDRCH may also include one or more intermediate preambles. For example, the length of the aforementioned one or more intermediate preambles may be the same as the length of the aforementioned preamble, i.e., both may be of the first length.

[0203] According to an embodiment of this application, a communication method is provided in which a reader / writer receives first data by indicating a first length of a first preamble and performing uplink synchronization based on the first length. This allows for flexible indication of the preamble length, thereby reducing the overhead of the synchronization signal while ensuring uplink synchronization performance.

[0204] For example, the above method can be used in random access scenarios for A-IoT devices.

[0205] Figure 8 shows a flowchart of another communication method provided in an embodiment of this application. Exemplarily, the method may include the following steps:

[0206] The S801 / S802 reader identifies the selected A-IoT device or group of A-IoT devices, and then sends a paging message (or trigger message) to initiate the random access process.

[0207] For a detailed implementation of this step, please refer to steps S401 / S402 of the embodiment shown in Figure 4.

[0208] The difference is that the paging message / trigger information may include first information. This first information is used to indicate the first length of the first preamble. For a specific implementation of this first information, please refer to step S601 of the embodiment shown in FIG6.

[0209] S803.A-IoT devices preempt time slots and send the first message in the preempted time slot.

[0210] For a detailed implementation of this step, please refer to step S403 of the embodiment shown in Figure 4.

[0211] The first message includes a first preamble and first data. For example, the first data could be a random number identifier.

[0212] The length of the first preamble is the first length mentioned above.

[0213] S804. The reader sends a second message.

[0214] In some implementations, if the reader receives the first message and successfully obtains the random number identifier in the first message, the reader will send a second message to the A-IoT device.

[0215] For a detailed implementation of this step, please refer to step S404 of the embodiment shown in Figure 4.

[0216] The difference is that the second message may include second information, which indicates the second length of the second preamble. The specific implementation of this second information can refer to the first information.

[0217] It is understandable that the second message may not include the second information, and the length of the second preamble is the same as the length of the first preamble.

[0218] S805.A-IoT devices send third messages.

[0219] For a detailed implementation of this step, please refer to step S405 of the embodiment shown in Figure 4.

[0220] The third message includes a second preamble and second data. For example, the second data may be the identification information of the A-IoT device. This identification information may be a permanent identifier or a temporary identifier. The permanent identifier may be, for example, the EPC of the A-IoT device. This application embodiment does not limit this.

[0221] As previously stated, if the second message includes the second information, the second preamble uses the second length indicated by the second information; if the second message does not include the second information, the length of the second preamble is the same as the length of the first preamble.

[0222] S806. The reader sends the fourth message.

[0223] It should be noted that the step of the reader sending the fourth message is an optional step, which is represented by a dashed line in Figure 8.

[0224] For a detailed implementation of this step, please refer to step S406 of the embodiment shown in Figure 4.

[0225] According to a communication method provided in an embodiment of this application, the reader / writer receives data by indicating the length of the preamble and performing uplink synchronization based on the length. This allows for flexible indication of the preamble length, thereby reducing the overhead of the synchronization signal while ensuring uplink synchronization performance. Furthermore, the length of the preamble can be flexibly updated before each uplink transmission.

[0226] In this application, the phrase "sending information to... (e.g., an A-IoT device)" or the related illustrations in the accompanying drawings can be understood as the destination of the information being an A-IoT device. This can include sending information directly or indirectly to an A-IoT device. Similarly, the phrase "receiving information from... (e.g., an A-IoT device)" or "receiving information from... (e.g., an A-IoT device)" or the related illustrations in the accompanying drawings can be understood as the source of the information being an A-IoT device. This can include receiving information directly or indirectly from an A-IoT device. Information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be interpreted similarly, and will not be elaborated further here.

[0227] It is understood that this application uses A-IoT devices and readers as examples to illustrate the interaction, but this application does not limit the subjects that can be used to illustrate the interaction. For example, the A-IoT device in the method provided by this application can also be a chip, chip system, or processor applied to the A-IoT device, or it can be a logical node, logical module, or software that can implement all or part of the A-IoT device; the reader in the method provided by this application can also be a chip, chip system, or processor applied to the reader, or it can be a logical node, logical module, or software that can implement all or part of the reader's functions.

[0228] It is understood that, in order to achieve the functions in the above embodiments, the reader and A-IoT device include hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0229] Figures 9 and 10 are schematic diagrams of possible communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of A-IoT devices or readers in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of this application, the communication device can be one of the terminals 120a-120j shown in Figure 1, or it can be a base station 110a or 110b shown in Figure 1, or it can be a module (such as a chip) applied to A-IoT devices or readers.

[0230] As shown in Figure 9, the communication device 900 includes a processing unit 910 and a transceiver unit 920. The communication device 900 is used to implement the functions of the A-IoT device or reader / writer in the method embodiments shown in Figures 6 and 8 above.

[0231] When the communication device 900 is used to implement the functions of an A-IoT device: the transceiver unit 920 is used to implement at least one step performed by the A-IoT device in S601 and S602 of the embodiment shown in FIG6, including the transceiver unit 920 receiving first information, wherein the first information is used to indicate the first length of the first preamble; the transceiver unit 920 is also used to send a PDRCH, the PDRCH including the first preamble and first data, the first preamble being located before the first data, and the first preamble being used for synchronization of the first data.

[0232] When the communication device 900 is used to implement the function of a reader / writer: the transceiver unit 920 is used to implement at least one step performed by the reader / writer in S601 and S602 of the embodiment shown in FIG6, including the transceiver unit 920 transmitting first information, wherein the first information is used to indicate the first length of the first preamble; the transceiver unit 920 is also used to receive PDRCH, the PDRCH including the first preamble and first data, the first preamble being located before the first data, and the first preamble being used for synchronization of the first data.

[0233] A more detailed description of the processing unit 910 and the transceiver unit 920 can be obtained directly from the relevant descriptions in the method embodiments shown in Figures 6 and 8, and will not be repeated here.

[0234] When the aforementioned communication device is a chip used in an A-IoT device, the A-IoT device chip implements the functions of the A-IoT device in the above method embodiments. The A-IoT device chip receives information from other modules (such as a radio frequency module or antenna) in the A-IoT device, which is sent to the A-IoT device by the reader; or, the A-IoT device chip sends information to other modules (such as a radio frequency module or antenna) in the A-IoT device, which is sent to the reader by the A-IoT device.

[0235] When the aforementioned communication device is a chip applied to a reader / writer, the reader / writer chip implements the functions of the reader / writer in the above method embodiments. The reader / writer chip receives information from other modules (such as an RF module or antenna) in the reader / writer, which is sent to the reader / writer by the A-IoT device; or, the reader / writer chip sends information to other modules (such as an RF module or antenna) in the reader / writer, which is sent to the A-IoT device by the reader / writer.

[0236] Furthermore, it should be noted that the aforementioned transceiver unit and / or processing unit can be implemented through virtual modules. For example, the processing unit can be implemented through software functional units or virtual devices, and the transceiver unit can be implemented through software functions or virtual devices. Alternatively, the processing unit or transceiver unit can also be implemented through physical devices. For example, if the device is implemented using a chip / chip circuit, the transceiver unit can be an input / output circuit and / or a communication interface, performing input operations (corresponding to the aforementioned receiving operation) and output operations (corresponding to the aforementioned sending operation); the processing unit is an integrated processor, microprocessor, or integrated circuit.

[0237] As shown in Figure 10, the communication device 1000 includes a processor 1010 and may also include an interface circuit 1020. The processor 1010 and the interface circuit 1020 are coupled to each other. It is understood that the interface circuit 1020 can be a transceiver or an input / output interface. Optionally, the communication device 1000 may also include a memory 1030 (shown as a dashed line in Figure 10) for storing instructions executed by the processor 1010, or storing input data required by the processor 1010 to execute instructions, or storing data generated after the processor 1010 executes instructions.

[0238] When the communication device 1000 is used to implement the functions of an A-IoT device: the interface circuit 1020 is used to implement at least one step performed by the A-IoT device in S601 and S602 of the embodiment shown in FIG6, including the interface circuit 1020 receiving first information, wherein the first information is used to indicate the first length of the first preamble; the interface circuit 1020 is also used to send a PDRCH, the PDRCH including the first preamble and first data, the first preamble being located before the first data, and the first preamble being used for synchronization of the first data.

[0239] When the communication device 1000 is used to implement the function of a reader / writer: the interface circuit 1020 is used to implement at least one step performed by the reader / writer in S601 and S602 of the embodiment shown in FIG6, including the interface circuit 1020 being used to send first information, wherein the first information is used to indicate the first length of the first preamble; the interface circuit 1020 is also used to receive PDRCH, the PDRCH including the first preamble and first data, the first preamble being located before the first data, and the first preamble being used for synchronization of the first data.

[0240] A more detailed description of the processor 1010 and interface circuit 1020 can be obtained directly from the relevant descriptions in the method embodiments shown in Figures 6 and 8, and will not be repeated here.

[0241] When the aforementioned communication device is a chip applied to a terminal, the terminal chip implements the functions of the terminal in the above method embodiments. The terminal chip receives information from the base station, which can be understood as the information being first received by other modules in the terminal (such as an RF module or antenna), and then sent to the terminal chip by these modules. The terminal chip sends information to the base station, which can be understood as the information being first sent to other modules in the terminal (such as an RF module or antenna), and then sent to the base station by these modules.

[0242] When the aforementioned communication device is a chip applied to a base station, the base station chip implements the functions of the base station in the above method embodiments. The base station chip receives information from the terminal, which can be understood as the information being first received by other modules in the base station (such as an RF module or antenna), and then sent to the base station chip by these modules. The base station chip sends information to the terminal, which can be understood as the information being sent down to other modules in the base station (such as an RF module or antenna), and then sent to the terminal by these modules.

[0243] In this application, entity A sends information to entity B, either directly or indirectly through other entities. Similarly, entity B receives information from entity A, either directly or indirectly through other entities. Entities A and B can be RAN nodes or terminals, or modules within RAN nodes or terminals. Information transmission and reception can be between RAN nodes and terminals, such as between a base station and a terminal; between two RAN nodes, such as between a CU and a DU; or between different modules within a single device, such as between a terminal chip and other modules of the terminal, or between a base station chip and other modules of the base station.

[0244] It is understood that in this application, "instruction" can include direct instruction, indirect instruction, explicit instruction, and implicit instruction. When describing a certain instruction information to indicate A, it can be understood that the instruction information carries A, directly indicates A, or indirectly indicates A. In this application, the information indicated by the instruction information is called the information to be instructed. In specific implementation, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index, or indirectly indicating the information to be instructed by indicating other information, wherein there is an association between the other information and the information to be instructed. It is also possible to indicate only a part of the information to be instructed, while the other parts of the information to be instructed are known or agreed upon in advance. For example, the instruction of specific information can also be achieved by using the arrangement order of various information in advance (e.g., as specified by a protocol), thereby reducing the instruction overhead to a certain extent. The information to be instructed can be sent as a whole or divided into multiple sub-information to be sent separately, and the sending period and / or sending time of these sub-information can be the same or different. This application does not limit the specific sending method. The sending period and / or timing of these sub-information messages can be predefined, for example, according to a protocol, or configured by the transmitting device by sending configuration information to the receiving device.

[0245] It is understood that the processor in the embodiments of this application can be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, field-programmable gate arrays, 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.

[0246] 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, optical discs, 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 application-specific integrated circuit (ASIC). Alternatively, the ASIC can reside in a base station or terminal. The processor and the storage medium can also exist as discrete components in the base station or terminal.

[0247] 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. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of 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 that a computer can access or a data storage device such as a server or data center that integrates 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.

[0248] 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.

[0249] Depending on whether the specification uses "optional": In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects. "Including at least one of A, B, and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B, and C.

[0250] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, characterized in that, The method includes: Receive first information, wherein the first information is used to indicate the first length of the first preamble; Transmit the Physical Device-Reader Channel (PDRCH), which includes a first preamble and first data. The first preamble precedes the first data and is used for synchronization of the first data.

2. A communication method, characterized in that, The method includes: Send first information, wherein the first information is used to indicate the first length of the first preamble; The Physical Device-Reader Channel (PDRCH) is received. The PDRCH includes a first preamble and first data. The first preamble is located before the first data and is used for synchronization of the first data.

3. The method as described in claim 1 or 2, characterized in that, The first information is used to indicate the first length of the first preamble, including: the first information includes a first index, which corresponds to the first length.

4. The method according to any one of claims 1-3, characterized in that, The first information is used to indicate the first length of the first preamble, including: the first information is used to configure the transmission parameters of the first data, the transmission parameters corresponding to the first length.

5. The method as described in claim 4, characterized in that, The transmission parameters of the first data include at least one of the following: the transmission bandwidth of the first data, the number of repetitions of the first data, and the bit rate of the first data.

6. The method as described in claim 5, characterized in that, The first length is A bits if at least one of the following first conditions is met: The transmission bandwidth of the first data is less than or equal to a first threshold; or, The number of repetitions of the first data is greater than or equal to the second threshold; or, The bit rate of the first data is less than or equal to the third threshold; The first length is B bits if at least one of the following second conditions is met: The transmission bandwidth of the first data is greater than the first threshold; or, The number of repetitions of the first data is less than the second threshold; or, The bit rate of the first data is greater than the third threshold; Where A is greater than B, and A and B are both positive integers.

7. The method according to any one of claims 1-6, characterized in that, The first length is 32 bits or 8 bits.

8. The method according to any one of claims 1-7, characterized in that, The first preamble is a first sequence of length 8*N, which is the same as the sequence obtained by repeating the first base sequence N times, where N is a positive integer greater than or equal to 1, and the length of the first base sequence is 8; or, The first preamble is an 8*N second base sequence.

9. The method according to any one of claims 1-8, characterized in that, The PDRCH also includes a postcode, the length of which is the first length.

10. The method according to any one of claims 1-9, characterized in that, The PDRCH also includes an intermediate code, the length of which is the first length.

11. The method according to any one of claims 1-10, characterized in that, When the number of repetitions M of the first data is greater than 1, the length of the first preamble is M times the first length, where M is a positive integer.

12. The method as described in claim 11, characterized in that, When the number of repetitions is greater than 1, the length of the first preamble is 16 bits or 64 bits.

13. A communication device, characterized in that, It includes modules for implementing the method as described in any one of claims 1, 3-12, or includes modules for implementing the method as described in any one of claims 2-12.

14. A communication device, characterized in that, The device includes a processor and an interface circuit. The interface circuit is used to receive signals from other communication devices and transmit them to the processor or to send signals from the processor to other communication devices. The processor is used to implement the method as described in any one of claims 1, 3-12, or to implement the method as described in any one of claims 2-12, through logic circuits or execution code instructions.

15. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed by a communication device, implement the method as described in any one of claims 1, 3-12, or the method as described in any one of claims 2-12.

16. A computer program product, characterized in that, The computer program product includes relevant program instructions, which, when executed, implement the method as described in any one of claims 1, 3-12, or the method as described in any one of claims 2-12.

17. A communication system, characterized in that, It includes a first communication device and a second communication device, wherein the first communication device is used to implement the method as described in any one of claims 1, 3-12, and the second communication device is used to implement the method as described in any one of claims 2-12.

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