Synchronization method and apparatus

Abstract

Embodiments of the present application provide a synchronization method and apparatus. The method comprises: a terminal device receives a first signal at a first frequency, the first signal comprising a first sub-signal and a second sub-signal, and the first signal being at least used for timing and / or time synchronization by the terminal device; and the terminal device sends a second signal at a second frequency at least on the basis of the first signal, the second signal being a signal formed by backscattering a first waveform by the terminal device or a signal autonomously generated by the terminal device.

Description

Synchronization method and device Technical Field

[0001] The embodiments of the present application relate to the field of communication technologies. Background Art

[0002] From the 2G era to the early days of 4G, cellular mobile communication systems primarily served mobile phones—mobile terminal devices held by people. With the rapid development of mobile internet and the Internet of Things (IoT), the technological evolution of cellular mobile communication systems, starting in the late 4G era and continuing to this day, has considered and supported an increasingly diverse range of IoT application scenarios. Consequently, a wider variety of IoT device types have been supported and implemented in actual network deployments and service applications, including eMTC, NB-IoT, and RedCap. With this increasing diversity of IoT terminal devices, cellular mobile systems have increasingly enhanced their capabilities for providing services tailored to vertical industries.

[0003] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art.

[0004] Summary of the Invention

[0005] The inventors discovered that among the vast number of IoT devices, cellular mobile communication systems still lack a large number of lower-cost IoT terminal devices. To provide more robust, reliable, and complete IoT application solutions, supporting lower-cost IoT terminal devices within the 3GPP cellular mobile system has become a pressing issue.

[0006] To address at least one of the above problems, embodiments of the present application provide a synchronization method and apparatus.

[0007] According to one aspect of an embodiment of the present application, a synchronization method is provided, including:

[0008] A terminal device receives a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device;

[0009] The terminal device sends a second signal at a second frequency based on at least the first signal, where the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0010] According to another aspect of an embodiment of the present application, a synchronization device is provided, including:

[0011] A receiving unit, configured to receive a first signal at a first frequency, wherein the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of a terminal device;

[0012] A sending unit sends a second signal at a second frequency based on at least the first signal, where the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0013] According to another aspect of an embodiment of the present application, a synchronization method is provided, including:

[0014] The network device sends a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device;

[0015] The network device receives a second signal at a second frequency, where the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0016] According to another aspect of an embodiment of the present application, a synchronization device is provided, including:

[0017] a sending unit configured to send a first signal at a first frequency, wherein the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of a terminal device;

[0018] A receiving unit receives a second signal at a second frequency, where the second signal is a signal formed by the terminal device through backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0019] According to another aspect of an embodiment of the present application, a communication system is provided, including:

[0020] A network device, which sends a first signal at a first frequency, the first signal including a first sub-signal and a second sub-signal, the first signal being used at least for timing and / or time synchronization of a terminal device; and receives a second signal at a second frequency;

[0021] A terminal device that receives the first signal at the first frequency and sends the second signal at the second frequency at least based on the first signal; the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal generated autonomously by the terminal device.

[0022] One of the beneficial effects of the embodiments of the present application is that a terminal device receives a first signal at a first frequency, the first signal including a first sub-signal and a second sub-signal, and transmits a second signal at a second frequency based on at least the first signal. This enables synchronization between a low-cost device and a network device, effectively reducing the complexity and cost of the terminal device.

[0023] With reference to the following description and accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the manner in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope. Within the spirit and scope of the appended claims, the embodiments of the present application include many variations, modifications and equivalents.

[0024] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0025] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The elements and features described in one figure or one embodiment of the present application can be combined with the elements and features shown in one or more other figures or embodiments. In addition, in the accompanying drawings, similar reference numerals represent corresponding parts in several figures and can be used to indicate corresponding parts used in more than one embodiment.

[0027] FIG1 is a schematic diagram of a communication system according to an embodiment of the present application;

[0028] FIG2 is another schematic diagram of a communication system according to an embodiment of the present application;

[0029] FIG3 is another schematic diagram of a communication system according to an embodiment of the present application;

[0030] FIG4 is a schematic diagram of a synchronization method according to an embodiment of the present application;

[0031] FIG5 is an example diagram of a first sub-signal symbol according to an embodiment of the present application;

[0032] FIG6 is an exemplary diagram of a first sub-signal and a second sub-signal according to an embodiment of the present application;

[0033] FIG7 is another example diagram of the first sub-signal and the second sub-signal according to an embodiment of the present application;

[0034] FIG8 is a diagram of an embodiment of the present application. M Example graph of a signal;

[0035] FIG9 is a schematic diagram of a synchronization method according to an embodiment of the present application;

[0036] FIG10 is a schematic diagram of a synchronization device according to an embodiment of the present application;

[0037] FIG11 is a schematic diagram of a synchronization device according to an embodiment of the present application;

[0038] FIG12 is a schematic diagram of a terminal device according to an embodiment of the present application;

[0039] FIG13 is a schematic diagram of a network device according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] The above and other features of the present application will become apparent through the following description with reference to the accompanying drawings. In the description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, which illustrate some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents that fall within the scope of the appended claims.

[0041] In the embodiments of the present application, the terms "first", "second", etc. are used to distinguish different elements from the name, but do not indicate the spatial arrangement or temporal order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the associated listed terms. The terms "comprising", "including", "having", etc. refer to the presence of the stated features, elements, components or components, but do not exclude the presence or addition of one or more other features, elements, components or components.

[0042] In the embodiments of this application, the singular forms "a," "the," etc. include plural forms and should be broadly understood to mean "a" or "a type" rather than being limited to "one." Furthermore, the term "said" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. Furthermore, the term "according to" should be understood to mean "at least in part based on...", and the term "based on" should be understood to mean "at least in part based on...", unless the context clearly indicates otherwise.

[0043] In the embodiments of the present application, the term "communication network" or "wireless communication network" may refer to a network that complies with any of the following communication standards, such as Long Term Evolution (LTE), enhanced Long Term Evolution (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0044] Furthermore, communication between devices in the communication system may be carried out according to communication protocols of any stage, for example, including but not limited to the following communication protocols: 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G and 5G, New Radio (NR), future 6G, etc., and / or other communication protocols currently known or to be developed in the future.

[0045] In the embodiments of the present application, the term "network device" refers to, for example, a device in a communication system that connects a terminal device to the communication network and provides services to the terminal device. Network devices may include, but are not limited to, the following devices: base station (BS), access point (AP), transmission reception point (TRP), broadcast transmitter, mobile management entity (MME), gateway, server, radio network controller (RNC), base station controller (BSC), etc.

[0046] Among them, base stations may include but are not limited to: NodeB (NodeB or NB), evolved NodeB (eNodeB or eNB) and 5G base station (gNB), IAB host (Donor), etc., and may also include remote radio head (RRH, Remote Radio Head), remote radio unit (RRU, Remote Radio Unit), relay (relay) or low-power node (such as femeto, pico, etc.). The term "base station" may include some or all of their functions. Each base station can provide communication coverage for a specific geographical area. The term "cell" can refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0047] In the embodiments of the present application, the term "user equipment" (UE) or "terminal equipment" (TE) refers to, for example, a device that accesses a communication network through a network device and receives network services. A terminal device can be fixed or mobile and may also be referred to as a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a tag, and so on.

[0048] Among them, terminal devices may include but are not limited to the following devices: cellular phones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, machine-type communication devices, laptop computers, cordless phones, smart phones, smart watches, digital cameras, tags, and devices attached to or related to objects, etc.

[0049] For another example, in scenarios such as the Internet of Things (IoT), the terminal device can also be a machine, device or equipment for monitoring, measurement, or item management, etc., and may include but is not limited to: machine type communication (MTC) terminals, vehicle-mounted communication terminals, device-to-device (D2D) terminals, machine-to-machine (M2M) terminals, ambient IoT devices (AIoT, Ambient IoT), etc.

[0050] In addition, the term "network side" or "network device side" refers to one side of the network, which can be a base station or one or more network devices as described above. The term "user side" or "terminal side" or "terminal device side" refers to the user or terminal side, which can be a UE or one or more terminal devices as described above. Unless otherwise specified herein, "device" can refer to either network equipment or terminal equipment.

[0051] RFID systems are a solution for the massive and cost-effective deployment of IoT devices. They are widely used. Their advantages include low tag costs and affordability. RFID tags are small, limiting the size and material of the items they can be used on, making them suitable for various scenarios such as item management and tracking. Despite their low tag costs, the deployment and operating costs of RFID systems are higher than those of wide-area commercial networks. Deployment is typically localized, using dedicated networks, making it difficult to effectively distribute deployment costs. Regarding usage, if manual handheld tag readers are used, labor costs can become a major expense and are difficult to reduce. Using dedicated RFID ports or gateways to read and manage tags significantly increases deployment costs. Furthermore, RFID systems have a simple logical architecture and loose radio resource management, making it difficult to effectively manage interference from radio wave transmissions. Consequently, RFID systems generally have low system capacity and spectrum efficiency.

[0052] Compared to existing RFID systems, leveraging existing commercial mobile communication cellular networks (such as LTE and 5G NR systems) to support industry applications requiring tag-based IoT devices can significantly reduce deployment costs, thereby lowering the barrier to entry for deploying these IoT devices. Furthermore, existing commercial mobile communication cellular networks (such as LTE and 5G NR systems) offer significantly higher network security and wireless resource management effectiveness than existing RFID systems.

[0053] Taking 5G systems as an example, they provide reliable authentication, network coordination, and accurate and stable terminal device management mechanisms. These systems can safely and effectively reduce labor costs, thereby lowering the cost of using this type of IoT. They can also optimize the network to increase system capacity and spectrum efficiency. These reductions in deployment and operating costs will effectively promote the application of these IoT devices in business management and industrial manufacturing, accelerating the digitalization of these industries, improving production efficiency, and ultimately promoting social development.

[0054] As a new type of IoT terminal in the 5G system, tag-type terminal devices (Ambient IoT devices, referred to as AIoT devices) are severely cost-constrained. The hardware capabilities of the devices are significantly weaker than those of ordinary smartphones and other IoT-type devices supported by existing cellular mobile communication systems. For example, tag-type terminal devices may not have a stable power supply (for example, using ambient energy harvesting instead of conventional batteries), have a narrow bandwidth, and the internal crystal oscillator has limited accuracy and large errors due to cost constraints, as well as limited signal processing capabilities.

[0055] Therefore, low-cost AIoT devices cannot reuse the existing synchronization signals of the 5G system to synchronize with network equipment. Achieving synchronization is a prerequisite for device-network communication. How to synchronize AIoT devices with network equipment has become a pressing issue.

[0056] The following describes the scenarios of the embodiments of the present application through examples, but the present application is not limited thereto.

[0057] Figure 1 is a schematic diagram of a communication system according to an embodiment of the present application, Figure 2 is another schematic diagram of a communication system according to an embodiment of the present application, and Figure 3 is yet another schematic diagram of a communication system according to an embodiment of the present application. Figures 1 to 3 schematically illustrate a situation using a terminal device and a network device as an example.

[0058] As shown in Figure 1, network devices can communicate directly with AIoT devices, directly sending signals to AIoT devices or directly receiving signals from AIoT devices; as shown in Figure 2, network devices can also go through an intermediate node and use the intermediate node to send signals to AIoT devices or use the intermediate node to receive signals from AIoT devices; as shown in Figure 3, network devices can also send signals to AIoT devices or receive signals from AIoT devices with the assistance of an assisting node.

[0059] The intermediate node can be a terminal device, a UE, or a network node, such as a relay, an IAB node, a repeater, etc., but the present application is not limited thereto. The intermediate node has the function of communicating with the network device in Figure 2, and at least has the ability to send signals to and receive signals from AIoT devices. The auxiliary node can be a terminal device, a UE, or a network node, such as a relay, an IAB node, a repeater, etc., but the present application is not limited thereto. The auxiliary node has the function of communicating with the network device in Figure 3, and at least has the ability to send signals to and / or receive signals from AIoT devices. The sending of signals to and receiving of signals from AIoT devices mentioned here comply with the provisions and descriptions of AIoT devices in the communication standard protocol.

[0060] In the embodiments of the present application, a network device may send signals / information / configurations to an AIoT device, or an AIoT device may receive signals / information / configurations from a network device. This may be done directly by the network device and received by the AIoT device, or by the network device via an intermediate node and received by the AIoT device, or by the network device with the help of an auxiliary node and received by the AIoT device, or by the network device using other methods and received by the AIoT device. Unless otherwise specified, this application is not limited to this.

[0061] In the embodiments of the present application, when an AIoT device sends a signal / information to a network device, or when a network device receives a signal / information from an AIoT device, the AIoT device may send the signal and the network device may receive it directly, or the AIoT device may send the signal and the network device may receive it via an intermediate node, or the AIoT device may send the signal and the network device may receive it with the help of an auxiliary node, or the AIoT device may send the signal and the network device may receive it through other methods. Unless otherwise specified, the present application is not limited to this.

[0062] In the existing 5G NR system and LTE system, the cell ID is obtained by the terminal device through the detection of the primary synchronization signal (PSS) and the secondary synchronization signal (SSS). Therefore, the number of cell IDs is related to the number of PSS signal sequences and SSS signal sequences. The existing 5G NR system has 1008 physical cell IDs, and the LTE system has 504 physical cell IDs. After the terminal device determines the sequences corresponding to the primary synchronization signal (PSS) and the secondary synchronization signal (SSS) during the detection process, it calculates the physical ID of the corresponding cell based on the corresponding parameters of the sequence. Since AIoT devices are extremely simple and it is difficult for them to have the ability to process long sequences and complex sequences, the synchronization signals in the existing 5G NR system are difficult to apply to AIoT devices.

[0063] On the other hand, in RFID systems, since they rely on symbol length to carry bit information, their synchronization signals are only used by tags to calibrate symbol length, thereby determining the hard decision threshold used when subsequently receiving data-carrying symbols. In RFID systems, there is no connection process between the reader and tag. The reader does not assign an ID to the tag; it only uses a temporary ID during communication and then releases it. The tag only verifies the reader's permission when the reader performs a read or write operation on it, without distinguishing one reader from another. If such a loose communication mechanism is applied to an AIoT system in the context of 5G NR, it may cause AIoT terminal devices to be unable to identify the network system. If an AIoT terminal device receives signals from more than one network device simultaneously, it will be unable to distinguish between the network devices. This is inconsistent with the inherently secure network architecture of the 5G NR system, is not conducive to network deployment and terminal device management, and makes it difficult to improve the efficiency of wireless resource utilization.

[0064] Therefore, how to design synchronization signals for AIoT terminal devices has become an urgent problem to be solved.

[0065] Embodiments of the first aspect

[0066] An embodiment of the present application provides a synchronization method, which is described from the perspective of a terminal device.

[0067] FIG4 is a schematic diagram of a synchronization method according to an embodiment of the present application. As shown in FIG4 , the method includes:

[0068] 401. A terminal device receives a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device.

[0069] 402. The terminal device sends a second signal at a second frequency based on at least the first signal, where the second signal is a signal formed by the terminal device by backscattering the first waveform or a signal autonomously generated by the terminal device.

[0070] It is worth noting that FIG4 above is merely a schematic illustration of an embodiment of the present application, and the present application is not limited thereto. For example, the execution order of the various operations may be appropriately adjusted, and other operations may be added or some operations may be reduced. Those skilled in the art may make appropriate modifications based on the above description, and are not limited to the description of FIG4 above.

[0071] Existing LTE systems and 5GNR systems are mainly based on OFDM signals, which are multi-carrier signals. Different terminal devices send their own signals to the network device at the same time. Their respective signals can use different subcarriers in the same bandwidth to carry their own information. The signals of different terminal devices are orthogonal to each other. Conversely, the network device can also modulate the information sent to different terminal devices onto different subcarriers. The subcarriers are orthogonal, and different terminal devices can obtain their own information on the corresponding subcarriers according to the instructions of the network device. Another waveform commonly used in existing LTE systems and 5GNR systems is SC-FDMA. This waveform is also a multi-carrier signal. Different users can achieve multiplexing by modulating different subcarriers at the same time.

[0072] In the embodiments of the present application, the first signal and / or the second signal are both single-carrier signals. Compared to multi-carrier signals, single-carrier signals have lower modulation and demodulation complexity and lower requirements on hardware capabilities and accuracy, which can effectively reduce the complexity and cost of terminal devices. Therefore, they are more suitable for AIoT-type terminal devices.

[0073] In some embodiments, the first signal is composed of a first sub-signal and a second sub-signal. The first sub-signal is at least used by the terminal device to identify the first signal in the time domain.

[0074] For example, the first sub-signal is unique and only appears in the front part of the first signal. For another example, the first sub-signal indicates that the first signal may appear. After the terminal device identifies the first sub-signal in the time domain, it judges / determines whether the second sub-signal follows. In other words, identifying the first sub-signal in the time domain means that the second sub-signal may follow; if the first sub-signal is not identified in the time domain, the terminal device does not need to judge / determine whether there is a second sub-signal. In other words, the first sub-signal can be sent alone, and after the terminal device receives the first sub-signal, there may or may not be a second sub-signal; or, the first sub-signal cannot be sent alone, and after the terminal device receives the first sub-signal, there is a second sub-signal.

[0075] In some embodiments, the first sub-signal may carry information. In other embodiments, the first sub-signal may not carry information.

[0076] The second sub-signal is at least used to carry information.

[0077] In one example, the first sub-signal does not carry information. For example, the first sub-signal may be a fixed symbol or waveform. In another example, the first sub-signal may be a symbol or waveform predefined by a standard protocol. This can improve the terminal device's recognition rate of the first sub-signal. The first sub-signal has fixed characteristics, and the terminal device detects the presence or absence of the signal based on these characteristics.

[0078] In another example, the first sub-signal can carry a small amount of information, such as 1 bit, 2 bits, or 3 bits. The first sub-signal carries a small amount of information, thereby better supporting network deployment in scenarios where multiple network devices coexist. For example, the small amount of information carried by the first sub-signal is related to the network device identifier. When a terminal device can receive first sub-signals from more than one network device, the terminal device can identify which network device a particular sub-signal comes from and perform subsequent operations accordingly.

[0079] In some embodiments, the first sub-signal does not carry information, and the signal waveform and / or the included time domain symbols are different from the time domain symbols of the second sub-signal and / or the subsequent time domain symbols carrying data information in at least one of the following aspects:

[0080] -The length of the symbol in the time domain;

[0081] - the distribution of the symbol high level during the symbol duration;

[0082] - the distribution of the low level of the symbol during the duration of the symbol;

[0083] -Distribution of high and low levels within the symbol pattern / symbol duration;

[0084] -The ratio of high level to low level in the symbol.

[0085] For example, when the first sub-signal is a continuous waveform, the waveform is a "symbol" as described above, or in other words, a "symbol" can correspond to a waveform in the time domain. The first sub-signal does not carry any information, which helps reduce the computational complexity of synchronization signal detection by the terminal device and increases the probability of the terminal device correctly detecting the first signal in the time domain.

[0086] In some embodiments, the first sub-signal includes one or more symbols.

[0087] Figure 5 is an example diagram of symbols of a first sub-signal according to an embodiment of the present application. As shown in Figure 5 , the first sub-signal includes one or more time-domain symbols. In one example, the first sub-signal includes one or more time-domain symbols, all of which have the same time-domain length. In another example, the first sub-signal includes one or more time-domain symbols, at least two of which have different time-domain lengths.

[0088] In some embodiments, the second sub-signal includes more than one symbol, and reference may also be made to FIG. 5 .

[0089] Figure 6 is an example diagram of the first sub-signal and the second sub-signal according to an embodiment of the present application. As shown in the upper half of Figure 6, the first sub-signal and the second sub-signal can be continuous in the time domain, or, as shown in the lower half of Figure 6, the first sub-signal and the second sub-signal can be discontinuous in the time domain.

[0090] For example, the first sub-signal does not carry information and is continuous with the second sub-signal. Once the terminal device recognizes the first sub-signal, it can immediately receive the second sub-signal. The time domain continuity of the first and second sub-signals helps speed up the terminal device's recognition of the first signal.

[0091] For another example, the first sub-signal carries information, and the first and second sub-signals are discontinuous, with a time interval between them. This time interval helps reserve sufficient time for the terminal device to receive and process the first sub-signal and obtain the information. For another example, this time interval can distinguish the first signal from other signals, helping to increase the probability of successful detection of the first signal.

[0092] Figure 7 is another example diagram of a first sub-signal and a second sub-signal according to an embodiment of the present application. As shown in Figure 7, the first sub-signal and the second sub-signal can be continuous in the time domain, or the first sub-signal and the second sub-signal can be discontinuous in the time domain. As shown in Figure 7, the second sub-signal can carry information and include one or more time-domain symbols.

[0093] The first sub-signal and the second sub-signal are schematically described above. The first signal will be further described below.

[0094] In some embodiments, the terminal device performs timing / time synchronization with the network device through the first signal, including at least one of the following:

[0095] The terminal device determines the symbol length and / or the starting point and / or the ending point of the signal from the network device;

[0096] The terminal device determines the length and / or starting point and / or ending point of a time unit of a signal from the network device;

[0097] The terminal device determines the length and / or starting point and / or ending point of the signal from the network device;

[0098] The terminal device determines a sampling clock and / or a sampling start position and / or a sampling frequency and / or a sampling end position for receiving a signal;

[0099] The terminal device determines the symbol length and / or the starting point and / or the ending point of the transmitted signal;

[0100] The terminal device determines the length and / or the starting point and / or the ending point of the time unit used for sending the signal;

[0101] The terminal device determines the start / length / end of the transmitted signal.

[0102] In the embodiment of the present application, after the terminal device performs timing / time synchronization with the network device, it receives information / signals from the network device and / or sends information / signals to the network device based on the timing / time synchronization result. This enables accurate and reliable information transmission and reception between low-cost devices and network devices.

[0103] In some embodiments, the first signal carries at least one of the following information: a first identifier, terminal device selection information, and information related to the sending of the second signal.

[0104] In one example, the first signal carries at least a first identifier. The first identifier corresponds to N bits. The first identifier is an identifier related to the network device. For example, the first identifier is an identifier of the network device, and / or an identifier of a cell corresponding to the network device, and / or an identifier of the region / site / area where the network device is located.

[0105] The area (Area) where the network device is located can be a network-defined area consisting of one or more network devices, or an area consisting of the service range of the above network devices, etc. Here, the area can also be a field (Field), domain (Domain), scenario (Scenario), range (Range), application range (Application Range), etc., and this application is not limited to this.

[0106] In an example, the value range of the first identifier may be the same as the physical ID of the traditional cell of the 5G NR system or the LTE system, or the value range of the first identifier may be different from the physical ID of the traditional cell of the 5G NR system or the LTE system.

[0107] For example, a network device can serve both mobile phones and other IoT devices, as well as AIoT devices. The cell IDs seen by mobile phones and / or other IoT devices are identical to those seen by AIoT devices. In one example, the range of cell / network device IDs serving AIoT devices matches the existing range of 1008 cell IDs supported by the traditional 5G NR system. This simplifies network planning and management. Reusing the existing range can also streamline standardization discussions and accelerate implementation.

[0108] For another example, the cell ID visible to AIoT devices may be inconsistent with the cell ID visible to mobile phones and / or other IoT devices. In one example, the value range of the cell / network device ID serving AIoT devices can be redefined. The original design of 1008 cell IDs was based on the properties of the existing NR system SS sequence. As mentioned earlier, this sequence is not applicable to AIoT scenarios. Redesigning the cell / network device ID serving AIoT devices can simplify the logic. For example, if N is 9, the cell / network device ID serving AIoT devices ranges from 0 to 511; or, if N is 10, the cell / network device ID serving AIoT devices ranges from 0 to 1023. For another example, N is 4, 6, or 8. For another example, N is 12 or 16.

[0109] In some embodiments, the first signal carries at least an N-bit first identifier. N may be a positive integer, such as 10. N may also be a non-positive integer, such as log2(1008) or log2(504).

[0110] In an example, the first sub-signal does not carry any information, and the N-bit first identifier is carried by the second sub-signal.

[0111] In one example, a first identifier corresponds to N bits and is carried by a first sub-signal and a second sub-signal. The first sub-signal is associated with M bits of the N bits corresponding to the first identifier, where M is less than or equal to N. The remaining bits of the N bits except M are carried by the second sub-signal.

[0112] M can be a positive integer, such as 1, 2, etc. M can also be a non-positive integer, for example, M can be log2(3) or log2(5), etc. The M bits can be the M bits starting from the most significant bit in the N bits, or the M bits starting from the least significant bit in the N bits, or the middle M bits in the N bits, but the present application is not limited thereto.

[0113] In some embodiments, the first sub-signal is 2 M The terminal device determines the M bits of information in the first identifier according to the first sub-signal.

[0114] FIG8 is a diagram of an embodiment of the present application. M In one embodiment, the network device includes 2 M From the set of different signals, a signal is selected based on the specific information of the M-bit information to be carried. The terminal device detects the first sub-signal and determines the corresponding M-bit information based on which of the above sets the first sub-signal belongs to.

[0115] As shown in Figure 8, taking M=2 as an example, the set contains 2 2 That is, there are a total of four possible sequences of first sub-signals to be selected. In one implementation, the information to be carried is "00," and the network device selects first sub-signal #0 from the set and sends it. The terminal device detects that it has received "sub-signal #0," and the M-bit information carried by this first sub-signal is "00." In another implementation, the information to be carried is "11," and the network device selects first sub-signal #3 from the set and sends it. The terminal device detects that it has received "sub-signal #3," and the M-bit information carried by this first sub-signal is "11."

[0116] The first sub-signal can carry M bits of information through the characteristics of the signal itself. The first sub-signal can be a bit string. For example, if M = 2, the first sub-signal is 00, 01, 10, or 11. The first sub-signal can also be a sequence. This sequence is relatively short, for example, significantly shorter than the existing NR system SS signal. For example, the sequence length is 4, 8, 16, etc. The sequence can be an integer sequence, for example, consisting of 0 and 1, or 1 and -1. The sequence can also be a simple complex sequence, for example, a discontinuous phase sequence.

[0117] In some embodiments, the first sub-signal may also be at least M symbols or M symbol strings, where one symbol in the M symbols differs from another symbol, or at least one symbol in one symbol string and another symbol string in the M symbol strings differ from each other in at least one of the following characteristics:

[0118] -The length of the symbol in the time domain;

[0119] - the distribution of the symbol high level during the symbol duration;

[0120] - the distribution of the low level of the symbol during the duration of the symbol;

[0121] -Distribution of high and low levels within the symbol pattern / symbol duration;

[0122] -The ratio of high level to low level in the symbol.

[0123] In some embodiments, the 2 M The two signals have the same length in the time domain. M A signal corresponds to one or more time domain symbols. In one example, the 2 M In another example, the time domain lengths of at least two symbols in the time domain symbols corresponding to the signal are not equal. M The length of at least one symbol in the time domain symbols corresponding to the signal is different from the length of the time domain symbol used to carry data.

[0124] In some embodiments, the second sub-signal carries at least part or all of one of the following information:

[0125] - a first identifier, where the first identifier is the network device identifier and / or the cell identifier corresponding to the network device;

[0126] -Terminal device selection information;

[0127] - information related to said second signalling.

[0128] For example, at least two of the symbols included in the second sub-signal for carrying the above information have equal time domain lengths. In one example, all symbols included in the second sub-signal for carrying the above information have equal time domain lengths. In another example, the symbols included in the second sub-signal for carrying the above information include symbols with unequal time domain lengths, for example, in order to adapt to the unit length of the existing system time (e.g., 5GNR system) so as to reduce the interference of the AIOT system on the existing 5GNR system and the interference of the existing 5GNR system on the AIOT system.

[0129] In some embodiments, the content carried by the second sub-signal includes a CRC check code, and the length of the CRC check code is Z bits. The first sub-signal does not include a CRC check code.

[0130] In one example, the second sub-signal includes a string of CRC check bits. For example, the string of CRC check bits is used to verify all information carried by the second sub-signal. In another example, the string of CRC check bits is used to verify part of the information carried by the second sub-signal. The string of check bits is used to verify information related to the second signal, or the string of CRC check bits is used to verify information related to the first identifier, etc., and the present application is not limited thereto.

[0131] In another example, the second sub-signal includes more than one string of CRC check bits. For example, one string of CRC check bits is used to check information related to the second signal, and another string of CRC check bits is used to check information related to the first identifier.

[0132] For example, the CRC check bits of the second sub-signal are 5 bits, 6 bits, 8 bits, 11 bits, 16 bits, 24 bits, etc.

[0133] For another example, the generator polynomial of the CRC check bits is one of the following: CRC24A (D)=[D 24 +D 23 +D 18 +D 17 +D 14 +D11 +D 10 +D 7 +D 6 +D 5 +D 4 +D 3 +D+1]for a CRC length 24; g CRC24B (D)=[D 24 +D 23 +D 6 +D 5 +D+1]for a CRC length 24; g CRC24C (D)=[D 24 +D 23 +D 21 +D 20 +D 17 +D 15 +D 13 +D 12 +D 8 +D 4 +D 2 +D+1]for a CRC length 24; g CRC16 (D)=[D 16 +D 12 +D 5 +1]for a CRC length 16; g CRC11 (D)=[D 11 +D 10 +D 9 +D 5 +1]for a CRC length 11; g CRC6 (D)=[D 6 +D 5 +1] for a CRC length 6.

[0134] In one example, the first signal (first sub-signal and second sub-signal) is transmitted using a single carrier with a bandwidth significantly narrower than that of existing 5G NR systems, for example, 180 kHz or 100 kHz, although this application is not limited thereto. The second sub-signal does not include a pilot. This reduces system overhead and frees up more radio resources for data transmission.

[0135] In some embodiments, the second sub-signal includes an end marker. In other embodiments, the second sub-signal does not include an end marker.

[0136] In one example, the second sub-signal includes an end marker, so that the terminal device can more accurately detect the end position of the second sub-signal, thereby increasing the probability of correct demodulation and / or decoding of the entire second sub-signal.

[0137] In another example, the second sub-signal does not include an end marker. The terminal device and the network device have a consistent understanding of the length, start, and / or end of the second sub-signal, as specified in the protocol standard. This reduces common signal overhead, leaving more wireless resources for data transmission and improving spectrum efficiency.

[0138] In some embodiments, at least two symbols among the symbols used to carry information included in the second sub-signal have the same time domain length.

[0139] In some embodiments, the second sub-signal includes a portion of the first identifier, or the second sub-signal includes the entire first identifier. For example, the second sub-signal includes at least the bits other than the M bits among the N bits corresponding to the first identifier.

[0140] The above schematically illustrates the first identifier, and the following further illustrates the terminal device selection information and / or information related to the second signal transmission.

[0141] In some embodiments, the second sub-signal further includes the terminal device selection information and / or information related to the sending of the second signal.

[0142] In some embodiments, the terminal device selection information is used by the network device to notify the terminal device to send the second signal related to the first signal, or not to send the second signal related to the first signal.

[0143] In some embodiments, the terminal device selection information is a selection condition and / or selection parameter, which is used by the terminal device to determine whether to send the second signal related to the first signal, or not to send the second signal related to the first signal.

[0144] In some embodiments, the terminal device selection information includes at least one of the following:

[0145] Terminal device identification;

[0146] Parameters / attributes of the terminal device;

[0147] The process (session / process) index of the terminal device;

[0148] Terminal device selection identifier;

[0149] Terminal equipment inventory identification.

[0150] In one example, the terminal device identifier includes, for example, a second identifier, second identification information, an inherent ID of the terminal device, and an ID configured / allocated / specified by the network device for the terminal device. The first signal carries the terminal device identifier, and the terminal device corresponding to the indicated terminal device identifier is selected or not selected. The terminal device compares the terminal device identifier carried by the first signal with its own terminal device identifier to determine whether it is selected or not. If the terminal device determines that it has been selected, the terminal device generates and sends the second information. If the terminal device determines that it has not been selected, it does not generate or send the second information.

[0151] In another example, the parameters / attributes of the terminal device include, for example: the service type of the terminal device, information about goods or items attached to / associated with the terminal device, capability parameters of the terminal device, types of services supported by the terminal device, and the like. The first signal carries the parameters / attributes of the terminal device, and the terminal device corresponding to the indicated parameters / attributes is selected or not selected. The terminal device compares the parameters / attributes carried by the first signal with its own parameters / attributes to determine whether it is selected or not. If the terminal device determines that it is selected, the terminal device generates and sends the second information. If the terminal device determines that it is not selected, it does not generate or send the second information.

[0152] In another example, the network device and / or the network can maintain one or more processes (session) or processes with the terminal device. A process corresponds to a service type or command type, for example, a process corresponds to a location information-related command or service, a process corresponds to a memory read and write-related command or service, a process corresponds to an inventory-related command or service, a process corresponds to an authentication-related security-related command, and so on. The first signal carries the process number of the terminal device, and the terminal device with the indicated process number is selected or not selected. The terminal device compares the process number carried by the first signal with its own process number to determine whether it is selected or not. The terminal device determines that it is selected, and the terminal device generates and sends the second information. If the terminal device determines that it is not selected, it does not generate or send the second information.

[0153] In another example, the first signal may also carry a terminal device selection identifier and / or a terminal device inventory identifier. For example, according to standard protocol specifications, the terminal side maintains the selection identifier, and the network device may operate the selection identifier. For example, in the previous round of communication or inventory, or in the previous round of communication related to a certain service or function, the network device has communicated with the terminal device and / or obtained necessary information from the terminal device. The network device commands the terminal device or the terminal device automatically sets the flag to "operated" (for example, the selection identifier can take values ​​such as "operated" or "not operated"), or the network device commands the terminal device or the terminal device automatically flips the flag (for example, the selection identifier is a 1-bit binary number, and flipping indicates that it has been operated). In this round of communication or inventory, the first signal carries information related to the terminal device selection identifier (for example, the value of the terminal device selection identifier, or whether the terminal device selection identifier was flipped in the previous round). The terminal device determines whether it has been selected or not in this round based on this information and its own terminal device selection identifier. If the terminal device determines that it has been selected, it generates and sends the second information. If the terminal device determines that it has not been selected, it does not generate or send the second information.

[0154] The above examples can be implemented separately or in combination. In some embodiments, the terminal device determines whether to generate and send the second information based on one or more of the above parameters. The one or more parameters can be carried entirely by the first signal (for example, by one or more first signals), or can be carried partially by the first signal and partially by other signals.

[0155] In some embodiments, the information related to the second signal transmission includes at least one of the following information:

[0156] information related to the second frequency,

[0157] time domain resource information related to the second signal,

[0158] information related to the time domain resource where the second signal is located,

[0159] information related to the content of the second signal,

[0160] Information related to the second signal sending method.

[0161] For example, the information related to the second frequency is at least one of the following: a center frequency point, a bandwidth, a starting frequency position, an ending frequency position, etc.

[0162] For another example, the time domain resource associated with the second signal may be a time domain resource for the terminal device to send the second signal, or may be a time domain resource available for the terminal device to send the second signal. The terminal device determines the time domain resource for sending the second information / second signal based on the time domain resource information. The network device indicates a resource, and the terminal device determines that the resource is used to send the second information / second signal. The network device indicates one or more available resources, and the terminal device determines a resource from the available resources to send the second information / second signal.

[0163] For another example, the information related to the content of the second signal may be the content contained in the second signal / second information indicated by the network device to the terminal device, such as the second identifier of the terminal device, the error code / reason for the previous communication / connection interruption, the power level, the location information, etc.

[0164] In some embodiments, the information related to the time domain resource where the second signal is located includes at least one of the following:

[0165] the starting position of the second signal time domain resource,

[0166] The time interval between the time domain resource of the second signal and the time domain location of the first signal,

[0167] The duration of the second signal (or the length of the time domain resources occupied, or the number of symbols of the second signal, or the number of time domain symbols occupied by the second signal),

[0168] Parameters used by the terminal device to determine time domain resources available for sending the second signal (such as a period, a starting position, an offset, etc.; which can be described in absolute time or in the number of time units),

[0169] a starting position, and / or a duration, and / or an ending position of a time domain resource that can be used for sending the second signal (for example, one or more starting positions, one or more durations, one or more ending positions, etc.; can be described in absolute time or in the number of time units);

[0170] Parameters used by the terminal device to select time domain resources for sending the second signal from time domain resources that can be used for sending the second signal (for example, parameters or seeds for generating random numbers, which are used to determine the position of the time domain resources for sending the second signal).

[0171] For example, the time domain resources available for sending the second signal are configured / indicated by the network device to the terminal device as one or more time domain resources available for sending the second signal. The terminal device determines to send the second signal in the time domain resource according to actual conditions, or the terminal device determines not to send the second signal in the time domain resource according to actual conditions.

[0172] In some embodiments, the information related to the second signal sending manner includes at least one of the following:

[0173] information related to the second signal preamble,

[0174] Information related to generating and / or sending a CRC checksum of the second signal,

[0175] information on the channel coding (forward error correction code) of the second signal,

[0176] information related to the second signal modulation,

[0177] Information related to the symbol length of the second signal.

[0178] In some embodiments, the first signal further carries one of the following information:

[0179] Parameters related to random access,

[0180] Parameters used for downlink data transmission,

[0181] Parameters used for uplink data transmission,

[0182] Parameters related to downlink control channels.

[0183] In some embodiments, the first signal carries or does not carry an index of a time unit, for example, a frame index.

[0184] In some embodiments, the first signal does not carry a time unit index. The limited hardware capabilities of the AIoT terminal device may not be able to maintain long-term synchronization with the network device. The absolute index of the time unit carried by the first signal (the index maintained by the network device) may not be significantly beneficial to the AIoT device. In contrast, it is more economical and effective for the AIoT terminal device to count the time units by itself with reference to the first signal for synchronization, or in other words, it is a more economical and effective method for the terminal device to maintain the relative index of the time unit. For example, the terminal device counts the index of the time domain symbol and / or time domain slot and / or subframe, etc., but the present application is not limited to this.

[0185] In some embodiments, the first signal carries a time unit index, or the first signal optionally carries a time unit index. For AIoT terminal devices with relatively high hardware computing and storage capabilities (for example, AIoT terminal devices capable of independently generating a second signal and other signals to be sent to a network device), supporting the first signal to carry a time unit index, or indicating that the first signal optionally carries a time unit index, can provide network devices with more flexibility to support more advanced and complex services, thereby enabling the AIoT system to have better forward compatibility.

[0186] The time unit is a symbol, a time slot, a subframe, a frame, etc.

[0187] In some embodiments, the first signal may also carry one or more of the following information: parameters related to random access (device inventory), parameters for downlink data transmission, parameters for uplink data transmission, parameters related to downlink control channels, etc.

[0188] The above schematically illustrates the content related to the first signal. The above information carried by the first signal can be carried by one first signal or by one or more first signals. Carrying by one first signal can reduce the implementation logic of the terminal device. Carrying by more than one first signal can provide more flexibility for network devices to better serve different businesses based on AIoT devices and AIoT devices with different capabilities.

[0189] The second signal is schematically described below.

[0190] In some embodiments, the second signal is a signal formed by the terminal device by backscattering the first waveform or a signal generated autonomously.

[0191] For example, backscatter can be sent by a network device or an intermediate node or an auxiliary node or a third-party device to send a waveform signal. The terminal device modulates the bit information to be sent onto the waveform signal through an adjustment circuit, and sends the modulated signal back to the network device or the intermediate node or the auxiliary node through reflection.

[0192] The first waveform can be a continuous waveform (CW), a carrier waveform (CW), a backscattered / backscattering wave, an uplink waveform, etc., but the present application is not limited thereto. The bandwidth of the first waveform is significantly narrower than the bandwidth of the first signal. For example, the bandwidth is 1 kHz, but the present application is not limited thereto.

[0193] In one example, the terminal device sends the second signal by backscattering a first waveform. The first waveform is a waveform sent by the network device or a third-party device. The terminal device modulates the information to be sent to the network device onto the first waveform by adjusting its backscatter circuit, and then backscatters the modulated first waveform.

[0194] For example, the terminal device receives the first waveform at a second frequency and backscatters the modulated first waveform at the second frequency. For another example, the terminal device receives the first waveform at a third frequency and backscatters the modulated first waveform at the second frequency.

[0195] In another example, the terminal device autonomously generates the second signal and transmits it at the second frequency. The terminal device autonomously generates a first waveform and modulates information to be sent to the network device onto the first waveform and transmits it as the second signal at the second frequency.

[0196] After receiving the second signal, the network device does not need to distinguish whether it is sent by the terminal device through backscattering or generated autonomously, and can use a unified receiving algorithm and mechanism to obtain the information carried on the second signal.

[0197] In some embodiments, the second signal is used to carry at least second identification information of the terminal device. The second identification information is used to identify the terminal device and / or is used by the network device to identify the terminal device. The second identification information is used to identify the terminal device within a range and / or a period of time. In one example, the second identification information uniquely identifies the terminal device within a range and / or a period of time; in another example, the second identification information uniquely corresponds to the terminal device within a range and / or a period of time; in yet another example, the second identification information has a one-to-one correspondence with the terminal device within a range and / or a period of time.

[0198] In some embodiments, the second identification information is at least one of the following: an inherent identifier of the terminal device, or a sequence or identifier generated or selected by the terminal device itself (randomly), or an identifier configured / allocated / specified by a network device for the terminal device, or other information used to identify the terminal device, etc.

[0199] The second identification information may be a number / serial number / index, sequence, or other information used to identify the terminal device, etc. The other information used to identify the terminal device may be inherent information such as the type / attributes of the terminal device, information / attributes of goods or items attached to / associated with the terminal device, application information of the terminal device, geographic information of the terminal device, location information of the terminal device, etc.

[0200] In one embodiment, the second identification information is a unique ID of the terminal device, such as a global identifier for electronic devices. This ID is written into the terminal device memory before the terminal device leaves the factory and serves as its globally unique long-term identifier. Accordingly, the aforementioned one range can be a cell corresponding to the network device and / or the range within which the unique ID is valid, and the aforementioned one time period can be from the time the terminal device leaves the factory until the terminal device is abandoned.

[0201] In another embodiment, the second identification information is a sequence or ID generated / selected by the terminal device itself. The second identification information is a sequence or ID generated / selected by the terminal device itself randomly or non-randomly. For example, the second identification information is a temporary ID generated / selected by the terminal device. The temporary ID is an ID generated / selected by the terminal device for temporary use. The temporary ID can subsequently become a formal terminal device identifier or can be replaced by other terminal device identifiers specified by the network device. For another example, when the terminal device is temporarily communicating / talking with the network device, and / or, the terminal device is in the initial random access process or random access process, and / or, the terminal device is in the process of requesting to access the network, and / or, the terminal device is in the process of requesting to resume communication / connection with the network device, the terminal device can use the above-mentioned randomly / autonomously generated / selected sequence or ID as the second identification information.

[0202] The second identification information is a sequence or ID generated / selected by the terminal device itself, and the aforementioned one range is a cell corresponding to the network device. The aforementioned one range may also be an area defined by a network (which may be implemented by the network device, core network, or other network device). The area may consist of one or more network nodes, the coverage area of ​​one or more network nodes, or the service area of ​​one or more network nodes.

[0203] The second identification information is a sequence or ID generated / selected by the terminal device itself, and the above-mentioned period of time is before the terminal device establishes a connection with the network device, or the above-mentioned period of time is the time when the terminal device is in a temporary communication / dialogue process with the network device. For example, when the network device does not specify an ID for the terminal device, in order to be able to identify the terminal device during the temporary communication / dialogue process, the terminal device and the network device use the temporary ID. The terminal device generates / selects an ID by itself and notifies the network device for identifying the terminal device. After the temporary communication / dialogue ends / terminates / is aborted, the ID is no longer used to identify the terminal device. In the next temporary communication / dialogue process, the terminal device randomly generates / selects another temporary ID again, and the temporary ID may be the same as or different from the previous temporary ID.

[0204] In another embodiment, the second identification information is an ID configured / allocated / specified by the network device for the terminal device. The above-mentioned one range can be a cell corresponding to the network device. The above-mentioned one range can also be an area defined by the network (which can be implemented by the network device or the core network or other network devices), which can be composed of one or more network nodes, or can be composed of the coverage area of ​​one or more network nodes, or can be composed of the service area of ​​one or more network nodes. The above-mentioned period of time can start from the ID that the network device previously configured / allocated / specified for the terminal device. For example, the terminal device previously obtained the ID in the connection / communication with the network device, and then the connection / communication was interrupted / suspended / paused / terminated. This time, the terminal device sends the second signal to request to resume the connection / communication. The terminal device can use the ID configured / allocated / specified by the above-mentioned network device for the terminal device as the second identification information for the network device to identify itself and the corresponding connection / communication.

[0205] In some embodiments, the second identification information is represented by L bits, where L is a positive integer, for example, L is 16, 24, 32, 48, etc.

[0206] In some embodiments, after sending the second information, the terminal device also receives third information from the network device, and the third information is at least used to carry a second identifier, and the second identifier is an identifier assigned / specified by the network device to the terminal device and / or an identifier of the terminal device confirmed by the network device, or the second identifier is an identifier reallocated / specified by the network device to the terminal device and / or an identifier of the terminal device reconfirmed by the network device.

[0207] In one example, the third information includes a second identifier, where the second identifier is an identifier assigned / specified by the network device to the terminal device and / or an identifier of the terminal device confirmed by the network device. The second identifier is represented by S bits, where S is a positive integer. For example, S is 10, another example is S is 16, and another example is S is 24, 32, or 48. The larger S is, the more terminal devices the ID set supports.

[0208] For example, the valid range of the terminal device ID is a network device or a cell or a region consisting of several network devices / cells / service areas. S The maximum number of supported terminal devices within the range that can be notified. A larger S indicates higher requirements for the capabilities of the network devices within the range. Consequently, due to the increased number of bits, higher requirements for the storage and data processing capabilities of the terminal devices are also required. Considering the relatively low hardware capabilities of AIoT devices, an appropriate value for S is recommended, for example, 16 or 24.

[0209] The third information also carries information for the terminal device to confirm the second identification information. Thus, the terminal device can confirm that the third information was sent to it by the network device. When a conflict occurs between the terminal device and another terminal device during the aforementioned process of sending the second signal, for example, when the terminal device and the other terminal device send a second signal to the network device using overlapping resources, the third information carrying information for the terminal device to confirm the second identification information facilitates conflict resolution, for example, helping the terminal device and the other terminal device confirm whether the third information is sent to themselves or to the other terminal device.

[0210] For example, the third information explicitly includes part or all of the second identification information, or the third signal used to carry the third information implicitly carries all of the second identification information. This allows the terminal device to determine that it is the receiving terminal device of the third information, or in other words, allows the terminal device to determine that the third information is sent to it by the network device.

[0211] In one example, the second identification information is a sequence or bit string of an identifier. The third information includes or carries part or all of the sequence or bit string carried by the third signal. For example, part of the bits of the sequence or bit string, such as the first X bits or the last X bits, and for example, the X bits starting from the most significant bit or the X bits starting from the least significant bit, where X is a positive integer, and X is less than or equal to the length of the sequence or bit string of the second identification information, and X is 5, 6, 10, 11, 16, etc. For example, as part of the third information. For another example, the third information is sent in a time domain resource corresponding to the time domain resource of the second information.

[0212] In some embodiments, the terminal device may further send fourth information to the network device, where the fourth information is at least used by the terminal device to notify the network device that it has correctly received the third information.

[0213] In some embodiments, the second signal and / or the third information and / or the fourth information include CRC check bits.

[0214] In one example, the second signal includes a string of CRC check bits. For example, the string of CRC check bits is used to verify all information carried by the second signal. For another example, the string of CRC check bits is used to verify part of the information carried by the second signal.

[0215] In another example, the second signal includes more than one string of CRC check bits. For example, one string of CRC check bits is used to check a portion of information, and another string of CRC check bits is used to check other information. CRC-related features can be found in the above content and will not be repeated here.

[0216] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used alone, or one or more of the above embodiments may be combined.

[0217] As can be seen from the above embodiment, a terminal device receives a first signal at a first frequency, the first signal comprising a first sub-signal and a second sub-signal, and transmits a second signal at a second frequency based on at least the first signal. This enables synchronization between low-cost devices and network devices, effectively reducing the complexity and cost of the terminal device.

[0218] Embodiments of the second aspect

[0219] The embodiment of the present application provides a synchronization method, which is described from the perspective of a network device. The embodiment of the second aspect can be combined with the embodiment of the first aspect, and the same contents as the embodiment of the first aspect will not be repeated.

[0220] FIG9 is a schematic diagram of a synchronization method according to an embodiment of the present application. As shown in FIG9 , the method includes:

[0221] 901: A network device sends a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of a terminal device.

[0222] 902. The network device receives a second signal at a second frequency, where the second signal is a signal formed by the terminal device through backscattering of the first waveform or a signal autonomously generated by the terminal device.

[0223] It is worth noting that FIG9 above is merely a schematic illustration of an embodiment of the present application, and the present application is not limited thereto. For example, the execution order of the various operations may be appropriately adjusted, and other operations may be added or some operations may be reduced. Those skilled in the art may make appropriate modifications based on the above description, and are not limited to the description of FIG9 above.

[0224] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used alone, or one or more of the above embodiments may be combined.

[0225] As can be seen from the above embodiment, a terminal device receives a first signal at a first frequency, the first signal comprising a first sub-signal and a second sub-signal, and transmits a second signal at a second frequency based on at least the first signal. This enables synchronization between low-cost devices and network devices, effectively reducing the complexity and cost of the terminal device.

[0226] Embodiments of the third aspect

[0227] The embodiment of the present application provides a synchronization device, which may be, for example, a terminal device, or one or more components or assemblies configured in the terminal device, and the same contents as those in the first and second aspects of the embodiment will not be repeated.

[0228] FIG10 is a schematic diagram of a synchronization device according to an embodiment of the present application. As shown in FIG10 , the synchronization device 1000 according to an embodiment of the present application includes:

[0229] A receiving unit 1001 is configured to receive a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device;

[0230] The sending unit 1002 sends a second signal at a second frequency according to at least the first signal, where the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0231] In some embodiments, the first signal carries at least one of the following information: a first identifier, terminal device selection information, and information related to the sending of the second signal.

[0232] In some embodiments, the first identifier is a network device identifier and / or a cell identifier corresponding to the network device.

[0233] In some embodiments, the first sub-signal includes one or more symbols, and the second sub-signal includes more than one symbol.

[0234] In some embodiments, at least one symbol included in the first sub-signal is different from at least one symbol included in the second sub-signal in at least one of the following characteristics:

[0235] The length of the symbol in the time domain;

[0236] The distribution of the symbol high level during the symbol duration;

[0237] The distribution of the low level of the symbol during the duration of the symbol;

[0238] The distribution of high and low levels within the symbol pattern / symbol duration;

[0239] The ratio of high level to low level in the symbol.

[0240] In some embodiments, the content carried by the second sub-signal includes a CRC check code, and the length of the CRC check code is Z bits.

[0241] In some embodiments, the first sub-signal does not include a CRC check code.

[0242] In some embodiments, the second sub-signal includes a portion of the first identifier, or the second sub-signal includes the entire first identifier.

[0243] In some embodiments, the first identifier corresponds to N bits.

[0244] In some embodiments, the first sub-signal is associated with M bits out of N bits corresponding to the first identifier, where M is less than or equal to N.

[0245] In some embodiments, the first sub-signal is 2 M The terminal device determines the M bits of information in the first identifier according to the first sub-signal.

[0246] In some embodiments, the 2 M The two signals have the same length in the time domain. M A signal corresponds to one or more time domain symbols.

[0247] In some embodiments, the 2 M At least one of the time domain symbols corresponding to the signal has at least one of the following characteristics different from the time domain symbol used to carry data:

[0248] The length of the symbol in the time domain;

[0249] The distribution of the symbol high level during the symbol duration;

[0250] The distribution of the low level of the symbol during the duration of the symbol;

[0251] The distribution of high and low levels within the symbol pattern / symbol duration;

[0252] The ratio of high level to low level of the symbol.

[0253] In some embodiments, the 2 M Among the time domain symbols corresponding to the signal, the time domain lengths of at least two symbols are not equal.

[0254] In some embodiments, the 2 M The length of at least one symbol in the time domain symbols corresponding to the signal is different from the length of the time domain symbol used to carry data.

[0255] In some embodiments, the second sub-signal includes at least the bits other than the M bits among the N bits corresponding to the first identifier.

[0256] In some embodiments, the second sub-signal further includes the terminal device selection information and / or information related to the sending of the second signal.

[0257] In some embodiments, at least two symbols among the symbols used to carry information included in the second sub-signal have the same time domain length.

[0258] In some embodiments, the terminal device selection information is used by the network device to notify the terminal device to send the second signal related to the first signal, or not to send the second signal related to the first signal.

[0259] In some embodiments, the terminal device selection information is a selection condition and / or selection parameter, which is used by the terminal device to determine whether to send the second signal related to the first signal, or not to send the second signal related to the first signal.

[0260] In some embodiments, the terminal device selection information includes at least one of the following:

[0261] Terminal device identification;

[0262] Parameters / attributes of the terminal device;

[0263] The process ID of the terminal device;

[0264] Terminal device selection identifier;

[0265] Terminal equipment inventory identification.

[0266] In some embodiments, the information related to the second signal transmission includes at least one of the following information:

[0267] information related to the second frequency,

[0268] information related to the time domain resource where the second signal is located,

[0269] information related to the content of the second signal,

[0270] Information related to the second signal sending method.

[0271] In some embodiments, the information related to the time domain resource where the second signal is located includes at least one of the following:

[0272] the starting position of the second signal time domain resource,

[0273] The time interval between the time domain resource of the second signal and the time domain location of the first signal,

[0274] the second signal duration,

[0275] a parameter used by the terminal device to determine a time domain resource available for sending the second signal;

[0276] a starting position, and / or duration, and / or end position of a time domain resource that can be used for transmitting the second signal;

[0277] Parameters used by the terminal device to select time domain resources for sending the second signal from time domain resources that can be used for sending the second signal.

[0278] In some embodiments, the information related to the second signal sending manner includes at least one of the following:

[0279] information related to the second signal preamble,

[0280] Information related to generating and / or sending a CRC checksum of the second signal,

[0281] information on the channel coding (forward error correction code) of the second signal,

[0282] information related to the second signal modulation,

[0283] Information related to the symbol length of the second signal.

[0284] In some embodiments, the second signal is used to carry at least second identification information of the terminal device, and the second identification information is used to identify the terminal device within a range and / or a period of time.

[0285] In some embodiments, the second identification information is an inherent identifier of the terminal device, or a sequence or identifier generated or selected by the terminal device itself, or an identifier configured / allocated / specified by a network device for the terminal device.

[0286] In some embodiments, the content of the second signal includes a CRC check code, and the length of the CRC check code is Y bits.

[0287] In some embodiments, the first sub-signal carries a sequence of binary bits.

[0288] In some embodiments, the first signal further carries one of the following information:

[0289] Parameters related to random access,

[0290] Parameters used for downlink data transmission,

[0291] Parameters used for uplink data transmission,

[0292] Parameters related to downlink control channels.

[0293] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used alone, or one or more of the above embodiments may be combined.

[0294] It is worth noting that the above description only describes the components or modules related to the present application, but the present application is not limited thereto. The synchronization device 1000 may also include other components or modules, and for the specific contents of these components or modules, reference may be made to the relevant art.

[0295] In addition, for the sake of simplicity, FIG10 only illustrates the connection relationship or signal direction between various components or modules. However, it should be clear to those skilled in the art that various related technologies such as bus connection can be used. The above-mentioned components or modules can be implemented by hardware facilities such as processors, memories, transmitters, and receivers; the implementation of this application is not limited to this.

[0296] As can be seen from the above embodiment, a terminal device receives a first signal at a first frequency, the first signal comprising a first sub-signal and a second sub-signal, and transmits a second signal at a second frequency based on at least the first signal. This enables synchronization between low-cost devices and network devices, effectively reducing the complexity and cost of the terminal device.

[0297] Embodiments of the fourth aspect

[0298] The present application provides a synchronization device. The device may be, for example, a network device, an intermediate node, or an auxiliary node, or may be one or more components or assemblies configured on the network device, the intermediate node, or the auxiliary node. The contents that are the same as those in the first to third aspects of the embodiments are not repeated here.

[0299] FIG11 is another schematic diagram of a synchronization device according to an embodiment of the present application. As shown in FIG11 , the synchronization device 1100 includes:

[0300] A sending unit 1101 is configured to send a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device;

[0301] The receiving unit 1102 receives a second signal at a second frequency, where the second signal is a signal formed by the terminal device through backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0302] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used alone, or one or more of the above embodiments may be combined.

[0303] It is worth noting that the above description only describes the components or modules related to the present application, but the present application is not limited thereto. The synchronization device 1100 may also include other components or modules, and for details of these components or modules, reference may be made to related technologies.

[0304] In addition, for the sake of simplicity, FIG11 only illustrates the connection relationship or signal direction between various components or modules. However, it should be clear to those skilled in the art that various related technologies such as bus connection can be used. The above-mentioned components or modules can be implemented by hardware facilities such as processors, memories, transmitters, and receivers; the implementation of this application is not limited to this.

[0305] As can be seen from the above embodiment, a terminal device receives a first signal at a first frequency, the first signal comprising a first sub-signal and a second sub-signal, and transmits a second signal at a second frequency based on at least the first signal. This enables synchronization between low-cost devices and network devices, effectively reducing the complexity and cost of the terminal device.

[0306] Embodiments of the fifth aspect

[0307] An embodiment of the present application also provides a communication system, and reference may be made to Figures 1 to 3 . The contents that are the same as those in the first to fourth embodiments will not be repeated.

[0308] In some embodiments, the communication system 100 may include at least:

[0309] A network device, configured to send a first signal at a first frequency, the first signal comprising a first sub-signal and a second sub-signal, the first signal being used at least for timing and / or time synchronization of a terminal device; and receive a second signal sent by the terminal device at a second frequency;

[0310] A terminal device that receives the first signal at the first frequency and sends the second signal at the second frequency at least based on the first signal; the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal generated autonomously by the terminal device.

[0311] The embodiment of the present application also provides a terminal device, but the present application is not limited thereto and may also be other devices.

[0312] Figure 12 is a schematic diagram of a terminal device according to an embodiment of the present application. As shown in Figure 12 , terminal device 1200 may include a processor 1210 and a memory 1220. For example, memory 1220 stores data and programs and is coupled to processor 1210. It should be noted that this diagram is exemplary; other types of structures may be used to supplement or replace this structure to implement telecommunication or other functions.

[0313] For example, the processor 1210 may be configured to execute a program to implement the synchronization method as described in the embodiment of the first aspect. For example, the processor 1210 may be configured to perform the following control: receiving a first signal at a first frequency, the first signal including a first sub-signal and a second sub-signal, the first signal being used at least for timing and / or time synchronization of a terminal device; and sending a second signal at a second frequency based at least on the first signal, the second signal being a signal formed by the terminal device by backscattering the first waveform or a signal autonomously generated by the terminal device.

[0314] As shown in FIG12 , the terminal device 1200 may further include a communication module 1230 and may or may not include a power supply. It is worth noting that the terminal device 1200 does not necessarily include all of the components shown in FIG12 , and the aforementioned components are not essential. Furthermore, the terminal device 1200 may also include components not shown in FIG12 , for which reference may be made to existing technologies.

[0315] An embodiment of the present application further provides a network device, which may be, for example, a base station, but the present application is not limited thereto and may also be other network devices.

[0316] Figure 13 is a schematic diagram illustrating the structure of a network device according to an embodiment of the present application. As shown in Figure 13 , network device 1300 may include a processor 1310 (e.g., a central processing unit (CPU)) and a memory 1320. Memory 1320 is coupled to processor 1310. Memory 1320 may store various data and may also store an information processing program 1330, which is executed under the control of processor 1310.

[0317] For example, the processor 1310 may be configured to execute a program to implement the synchronization method as described in the embodiment of the second aspect. For example, the processor 1310 may be configured to perform the following control: sending a first signal to a terminal device at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device; and receiving a second signal sent by the terminal device at a second frequency, where the second signal is a signal formed by the terminal device by backscattering the first waveform or a signal autonomously generated by the terminal device.

[0318] Furthermore, as shown in FIG13 , network device 1300 may further include a transceiver 1340 and an antenna 1350 . The functions of these components are similar to those in the prior art and are not further described here. It is worth noting that network device 1300 does not necessarily include all of the components shown in FIG13 . Furthermore, network device 1300 may also include components not shown in FIG13 , for which reference may be made to the prior art.

[0319] An embodiment of the present application also provides a computer program, wherein when the program is executed in a terminal device, the program causes the terminal device to execute the synchronization method described in the embodiment of the first aspect.

[0320] An embodiment of the present application also provides a storage medium storing a computer program, wherein the computer program enables a terminal device to execute the synchronization method described in the embodiment of the first aspect.

[0321] An embodiment of the present application also provides a computer program, wherein when the program is executed in a network device, the program causes the network device to execute the synchronization method described in the embodiment of the second aspect.

[0322] An embodiment of the present application also provides a storage medium storing a computer program, wherein the computer program enables a network device to execute the synchronization method described in the embodiment of the second aspect.

[0323] The above devices and methods of the present application can be implemented by hardware or by a combination of hardware and software. The present application relates to such a computer-readable program that, when executed by a logic component, enables the logic component to implement the devices or components described above, or enables the logic component to implement the various methods or steps described above. The present application also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0324] The method / device described in conjunction with the embodiments of the present application can be directly embodied as hardware, a software module executed by a processor, or a combination of the two. For example, one or more of the functional block diagrams shown in the figure and / or one or more combinations of functional block diagrams can correspond to various software modules of the computer program flow or to various hardware modules. These software modules can respectively correspond to the various steps shown in the figure. These hardware modules can be implemented by solidifying these software modules, for example, using a field programmable gate array (FPGA).

[0325] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium; or the storage medium may be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal or in a memory card that can be inserted into the mobile terminal. For example, if the device (such as a mobile terminal) uses a large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0326] One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may be implemented as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof for performing the functions described in this application. One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0327] The present application has been described above in conjunction with specific embodiments. However, those skilled in the art should understand that these descriptions are merely illustrative and are not intended to limit the scope of protection of the present application. Those skilled in the art may make various modifications and variations to the present application based on the spirit and principles of the present application, and such modifications and variations are also within the scope of the present application.

[0328] Regarding the implementation methods including the above embodiments, the following additional notes are also disclosed:

[0329] 1. A synchronization method, comprising:

[0330] A terminal device receives a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device;

[0331] The terminal device sends a second signal at a second frequency based on at least the first signal, where the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0332] 2. A synchronization method, comprising:

[0333] The network device sends a first signal at a first frequency, where the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of the terminal device;

[0334] The network device receives a second signal at a second frequency, where the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal autonomously generated by the terminal device.

[0335] 3. A terminal device comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the synchronization method as described in Note 1.

[0336] 4. A network device comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the synchronization method as described in Note 2.

[0337] 5. A computer program product, comprising at least a computer program, wherein when the computer program is executed by a processor, the terminal device executes the synchronization method as described in Note 1.

[0338] 6. A computer program product, comprising at least a computer program, wherein when the computer program is executed by a processor, the network device executes the synchronization method as described in Note 2.

Claims

1. A synchronization device, comprising: A receiving unit, configured to receive a first signal at a first frequency, wherein the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of a terminal device; A sending unit sends a second signal at a second frequency based on at least the first signal, where the second signal is a signal formed by the terminal device by backscattering the first waveform or is a signal autonomously generated by the terminal device.

2. The device according to claim 1, wherein The first signal carries at least one of the following information: a first identifier, terminal device selection information, and information related to the sending of the second signal; The first identifier is a network device identifier and / or a cell identifier corresponding to the network device.

3. The device according to claim 1, wherein The first sub-signal includes one or more symbols, and the second sub-signal includes more than one symbol; The at least one symbol included in the first sub-signal is different from the at least one symbol included in the second sub-signal in at least one of the following characteristics: The length of the symbol in the time domain; The distribution of the symbol high level during the symbol duration; The distribution of the low level of the symbol during the duration of the symbol; The distribution of high and low levels within the symbol pattern / symbol duration; The ratio of high level to low level in the symbol.

4. The device according to claim 1, wherein The content carried by the second sub-signal includes a CRC check code, and the length of the CRC check code is Z bits; And / or, the first sub-signal does not include a CRC check code.

5. The device according to claim 1, wherein The second sub-signal includes a portion of the first identifier, or the second sub-signal includes the entire first identifier; The first identifier corresponds to N bits; the first sub-signal is associated with M bits of the N bits corresponding to the first identifier, and M is less than or equal to N.

6. The device according to claim 5, wherein The first sub-signal is 2 M The terminal device determines the M bits of information in the first identifier according to the first sub-signal.

7. The device according to claim 6, wherein Said 2 M The two signals have the same length in the time domain. M A signal corresponds to one or more time domain symbols.

8. The device according to claim 7, wherein Said 2 M At least one of the time domain symbols corresponding to the signal has at least one of the following characteristics different from the time domain symbol used to carry data: The length of the symbol in the time domain; The distribution of the symbol high level during the symbol duration; The distribution of the low level of the symbol during the duration of the symbol; The distribution of high and low levels within the symbol pattern / symbol duration; The ratio of high level to low level of the symbol.

9. The device according to claim 7, wherein Said 2 M Among the time domain symbols corresponding to the signals, at least two symbols have unequal time domain lengths; and / or, said 2 M The length of at least one symbol in the time domain symbols corresponding to the signal is different from the length of the time domain symbol used to carry data.

10. The device according to claim 5, wherein The second sub-signal includes at least the bits other than the M bits among the N bits corresponding to the first identifier.

11. The device according to claim 2, wherein The second sub-signal further includes the terminal device selection information and / or information related to the transmission of the second signal; And / or, among the symbols used to carry information included in the second sub-signal, at least two symbols have the same time domain length.

12. The device according to claim 2, wherein The terminal device selection information is used by the network device to notify the terminal device to send the second signal related to the first signal, or not to send the second signal related to the first signal; Alternatively, the terminal device selection information is a selection condition and / or selection parameter, which is used by the terminal device to determine whether to send the second signal related to the first signal, or not to send the second signal related to the first signal.

13. The device according to claim 2, wherein The terminal device selection information includes at least one of the following: Terminal device identification; Parameters / attributes of the terminal device; The process ID of the terminal device; Terminal device selection identifier; Terminal equipment inventory identification.

14. The device according to claim 2, wherein The information related to the second signal transmission includes at least one of the following information: information related to the second frequency, information related to the time domain resource where the second signal is located, information related to the content of the second signal, Information related to the second signal sending method.

15. The device according to claim 14, wherein The information related to the time domain resource where the second signal is located includes at least one of the following: the starting position of the second signal time domain resource, The time interval between the time domain resource of the second signal and the time domain location of the first signal, the second signal duration, a parameter used by the terminal device to determine a time domain resource that can be used for sending the second signal, a starting position, and / or duration, and / or end position of a time domain resource that can be used for transmitting the second signal; Parameters used by the terminal device to select a time domain resource for sending the second signal from time domain resources that can be used for sending the second signal; The information related to the second signal sending mode includes at least one of the following: information related to the second signal preamble, Information related to generating and / or sending a CRC checksum of the second signal, information related to channel coding of the second signal, information related to the second signal modulation, Information related to the symbol length of the second signal.

16. The device according to claim 1, wherein The second signal is used to carry at least second identification information of the terminal device, where the second identification information is used to identify the terminal device within a range and / or a period of time; The second identification information is the inherent identification of the terminal device, or the terminal device itself A sequence or identifier generated or selected by a network device, or an identifier configured / allocated / specified by a network device for the terminal device.

17. The device according to claim 1, wherein The content of the second signal includes a CRC check code, and the length of the CRC check code is Y bits; And / or, the first sub-signal carries a sequence composed of binary bits.

18. The device according to claim 1, wherein The first signal also carries one of the following information: Parameters related to random access, Parameters used for downlink data transmission, Parameters used for uplink data transmission, Parameters related to downlink control channels.

19. A synchronization device comprising: a sending unit configured to send a first signal at a first frequency, wherein the first signal includes a first sub-signal and a second sub-signal, and the first signal is used at least for timing and / or time synchronization of a terminal device; A receiving unit receives a second signal at a second frequency, where the second signal is a signal formed by the terminal device through backscattering the first waveform or is a signal autonomously generated by the terminal device.

20. A communication system comprising: A network device, which sends a first signal at a first frequency, the first signal including a first sub-signal and a second sub-signal, the first signal being used at least for timing and / or time synchronization of a terminal device; and receives a second signal at a second frequency; A terminal device that receives the first signal at the first frequency and sends the second signal at the second frequency at least based on the first signal; the second signal is a signal formed by the terminal device by backscattering the first waveform or a signal generated autonomously by the terminal device.

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