Synchronization method and communication device

Abstract

The present application provides a synchronization method and a communication apparatus, which can be applied to NTN, such as a satellite communication system. The method includes: receiving a synchronization signal, where the synchronization signal is generated according to a first synchronization sequence, and the first synchronization sequence satisfies: 0 ≤ m < N; performing frequency synchronization based on the synchronization signal; where, x q (m) represents the first synchronization sequence, q represents a root index of the first synchronization sequence, N represents the length of the first synchronization sequence, and the first synchronization sequence can also be expressed as a linear combination of and. By receiving the synchronization signal generated by the synchronization sequence that can be expressed as one ZC sequence and the conjugate sequence of the ZC sequence, the receiving end apparatus can perform sliding correlation operation in the subsequent frequency synchronization process based on the ZC sequence and the conjugate sequence of the ZC sequence, which reduces the complexity of frequency synchronization, so that the synchronization performance can be improved.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to a synchronization method and a communication apparatus. Background Technology

[0002] In wireless communication systems, the foundation for establishing a connection between the transmitter and receiver includes time and frequency synchronization. Time synchronization aims to allow the receiver to pinpoint the time-domain boundaries of the transmitted signal, enabling it to process the received signal on a time-unit basis (e.g., system frame, time slot, or symbol). Frequency synchronization refers to the process by which the receiver, while generating its own carrier signal, aligns the frequency of its local carrier signal with the carrier frequency of the transmitter's signal. In dual-communication, the transmitter uses a specific carrier frequency, e.g., fc = 2 GHz. The receiver then needs to down-convert the carrier signal to baseband for processing. During down-conversion, the receiver must generate a local carrier signal with a frequency of fc = 2 GHz to convert the received signal to baseband.

[0003] In existing solutions, the performance of time and frequency synchronization is related to the range of frequency deviation between the transmitting and receiving parties. For example, the complexity of time and frequency synchronization increases with the increase of the frequency deviation range. With the evolution of communication technology, mobile communication scenarios are becoming increasingly complex. In some cases, large frequency errors may occur between the transmitting and receiving parties, significantly increasing the complexity of frequency synchronization. Furthermore, some low-cost devices may also suffer from large frequency deviations. For example, some Internet of Things (IoT) devices use low-cost, low-precision crystal oscillators, which may exhibit a large frequency deviation range. Therefore, reducing the complexity of time and frequency synchronization is a problem that needs to be addressed. Summary of the Invention

[0004] This application provides a synchronization method and communication device to reduce the complexity of frequency synchronization and thereby improve the synchronization performance of terminal devices.

[0005] Firstly, a synchronization method is provided, applicable to a receiving device. This receiving device can be a terminal device, or a module, circuit, or chip that can be configured within the terminal device (such as a modem chip, also known as a baseband chip, or a system-on-a-chip (SoC) chip or system-in-package (SIP) chip containing a modem core, etc.), or a logic module or software capable of implementing some or all of the functions of the terminal device. Alternatively, the receiving device can be a network device, or a module, circuit, or chip that can be configured within the network device (such as a chip or circuit, which can be a modem chip, also known as a baseband chip, or an SoC or SIP chip containing a modem core, etc.), or a logic module or software capable of implementing some or all of the functions of the network device, etc. This application does not limit this aspect.

[0006] The method includes: receiving a synchronization signal, the synchronization signal being generated based on a first synchronization sequence, the first synchronization sequence satisfying: Frequency synchronization is performed based on this synchronization signal; wherein, x q (m) represents the first synchronization sequence, q represents the root index of the first synchronization sequence, N represents the length of the first synchronization sequence, and α is a real or complex number. The first synchronization sequence can also be represented as... and A linear combination of .

[0007] Based on the above scheme, by receiving a synchronization signal generated from a synchronization sequence that can be represented as a ZC sequence and a conjugate sequence of the ZC sequence, the receiving device can perform sliding correlation operations in the subsequent frequency synchronization process based on the ZC sequence and the conjugate sequence of the ZC sequence, thereby reducing the complexity of frequency synchronization and improving the synchronization performance of the receiving device.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, a baseband signal is obtained by processing the synchronization signal based on the first carrier signal, wherein the frequency of the first carrier signal is adjusted based on a first frequency value, the first frequency value belongs to a first frequency range, and the first frequency range is less than or equal to the subcarrier spacing corresponding to the subcarrier that transmits the synchronization signal; frequency synchronization is performed based on a sampling sequence obtained by sampling the baseband signal.

[0009] For example, the first carrier signal can be understood as the local carrier signal of the receiving device.

[0010] Based on the above scheme, by selecting a frequency compensation value (i.e., the first frequency value) within the frequency deviation range of the subcarrier interval corresponding to the subcarrier that transmits the synchronization signal, the frequency compensation of the local carrier signal can be reduced, thereby reducing the number of subsequent sliding correlation operations based on the frequency compensation value and thus reducing the complexity of frequency synchronization.

[0011] The first frequency value can be understood as the fractional frequency offset included in the frequency deviation between the receiving device and the transmitting device, that is, a frequency offset less than or equal to one subcarrier interval.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, a second frequency value is determined based on the sampling sequence and the second synchronization sequence, the second synchronization sequence being generated by the receiving end, the second synchronization sequence including the first sequence and the conjugate sequence of the first sequence; frequency synchronization is performed based on the second frequency value.

[0013] For example, the first sequence is represented as the

[0014] Based on the above scheme, the receiving device can determine a second frequency value based on the generated local synchronization sequence (i.e., the second synchronization sequence) and the sampling sequence obtained by sampling the baseband signal, and perform frequency synchronization based on the second frequency value. The local synchronization sequence includes a ZC sequence that can be represented as a linear combination of the first synchronization sequence and a conjugate sequence of the ZC sequence.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, a portion of the sampled sequence is sequentially truncated using a sliding window; each truncated portion of the sequence is correlated with a second sequence and a third sequence to obtain a first correlation value and a second correlation value, wherein the second sequence is the time-domain sequence corresponding to the first sequence, and the third sequence is the time-domain sequence corresponding to the conjugate sequence of the first sequence; the second frequency value is determined based on the time interval between the first time-domain position and the second time-domain position, wherein the first time-domain position is the time-domain position where the first correlation value reaches its maximum, and the second time-domain position is the time-domain position where the second correlation value reaches its maximum.

[0016] Based on the above scheme, the second frequency value can be determined by the correlation peak obtained by the correlation operation of the ZC sequence and the sampling sequence included in the local synchronization sequence, and the correlation peak obtained by the correlation operation of the conjugate sequence of the ZC sequence and the sampling sequence. The second frequency value can be understood as the integer frequency offset included in the frequency deviation between the receiving device and the transmitting device. Thus, the receiving device can perform frequency synchronization based on the first frequency value and the second frequency value, reducing the complexity of frequency synchronization by the receiving device.

[0017] In conjunction with the first aspect, in some implementations of the first aspect, time synchronization is performed based on the first time domain position and the second time domain position.

[0018] Based on the above scheme, by using the time domain position of the correlation peak obtained by the correlation operation of the ZC sequence and the sampling sequence included in the local synchronization sequence, and the time domain position of the correlation peak obtained by the correlation operation of the conjugate sequence of the ZC sequence and the sampling sequence, the time deviation between the receiving device and the transmitting device can be determined, thereby enabling time synchronization.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the root index corresponding to the first synchronization sequence is an element in a first set, which includes one or more root indices, and any two root indices among the plurality of root indices are different.

[0020] Based on the above scheme, when the elements in the first set are all different from each other, and when one element in the first set is selected as the synchronization sequence for the receiving device to synchronize, the interference between the receiving device and other receiving devices using the other elements in the first set to synchronize can be reduced.

[0021] Secondly, a synchronization method is provided, applicable to a receiving device. This receiving device can be a terminal device, or a module, circuit, or chip (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core, etc.) that can be configured within the terminal device, or a logic module or software capable of implementing some or all of the functions of the terminal device. Alternatively, the receiving device can be a network device, or a module, circuit, or chip (such as a chip or circuit, which can be a modem chip, also known as a baseband chip, or a SoC or SIP chip containing a modem core, etc.) that can be configured within the network device, or a logic module or software capable of implementing some or all of the functions of the network device. This application does not limit this aspect.

[0022] The method includes: receiving a first synchronization signal and a second synchronization signal, wherein the first synchronization signal is generated based on a first synchronization sequence, the second synchronization sequence is generated based on a second synchronization sequence, and the first synchronization sequence satisfies: The second synchronization sequence satisfies: Frequency synchronization is performed based on the first synchronization signal and the second synchronization signal; where x q1 (m) represents the first synchronization sequence, q1 represents the root index of the first synchronization sequence, and x q2(m) represents the second synchronization sequence, q2 represents the root index of the second synchronization sequence, the values ​​of q1 and q2 are different, and N represents the length of the first synchronization sequence and the second synchronization sequence.

[0023] Based on the above scheme, by receiving the first synchronization signal and the second synchronization signal generated by two ZC sequences with different root indices (i.e., the first synchronization sequence and the second synchronization sequence), the terminal device can perform sliding correlation operations in the subsequent frequency synchronization process based on the first synchronization sequence and the second synchronization sequence, thereby reducing the complexity of frequency synchronization and improving the synchronization performance of the terminal device.

[0024] In conjunction with the second aspect, in some implementations of the second aspect, the first synchronization signal is received on a first time-frequency resource; the second synchronization signal is received on a second time-frequency resource; wherein the time domain position or frequency domain position corresponding to the first time-frequency resource and the second time-frequency resource are different.

[0025] In other words, the time-frequency resources where the first synchronization signal and the second synchronization signal are located are orthogonal, and can be arranged in a time-division or frequency-division manner without any limitation.

[0026] In conjunction with the second aspect, in some implementations of the second aspect, a first baseband signal and a second baseband signal are obtained by processing the first synchronization signal and the second synchronization signal based on the first carrier signal, respectively. The frequency of the first carrier signal is adjusted based on a first frequency value, which belongs to a first frequency range. The first frequency range is less than or equal to the subcarrier spacing corresponding to the subcarrier that transmits the synchronization signal. Frequency synchronization is performed based on a first sampling sequence and a second sampling sequence, where the first sampling sequence is obtained by sampling the first baseband signal and the second sampling sequence is obtained by sampling the second baseband signal.

[0027] Based on the above scheme, by selecting a frequency compensation value (i.e., the first frequency value) within the frequency deviation range of the subcarrier interval corresponding to the subcarrier that transmits the synchronization signal, the frequency compensation of the local carrier signal can be reduced, thereby reducing the number of subsequent sliding correlation operations based on the frequency compensation value and thus reducing the complexity of frequency synchronization.

[0028] In conjunction with the second aspect, in some implementations of the second aspect, a second frequency value is determined based on the first sampling sequence, the second sampling sequence, and the third synchronization sequence, the third synchronization sequence being generated by the receiving end; frequency synchronization is performed based on the second frequency value.

[0029] In conjunction with the second aspect, in some implementations of the second aspect, the second synchronization sequence includes the first synchronization sequence and the second synchronization sequence.

[0030] Based on the above scheme, the receiving device can determine the second frequency value based on the generated local synchronization sequence (i.e., the third synchronization sequence), the first sampling sequence obtained by sampling the first baseband signal and the second baseband signal respectively, and perform frequency synchronization based on the second frequency value, wherein the local synchronization sequence includes the first synchronization sequence and the second synchronization sequence.

[0031] In conjunction with the second aspect, in some implementations of the second aspect, a portion of the first sampling sequence is sequentially truncated using a sliding window at the time-domain position corresponding to the first time-frequency resource; a third correlation value is obtained by performing a correlation operation between each truncated portion of the first sampling sequence and a fourth sequence, where the fourth sequence is the time-domain sequence corresponding to the first synchronization sequence; a portion of the second sampling sequence is sequentially truncated using a sliding window at the time-domain position corresponding to the second time-frequency resource; a fourth correlation value is obtained by performing a correlation operation between each truncated portion of the second sampling sequence and a fifth sequence, where the fifth sequence is the time-domain sequence corresponding to the second synchronization sequence; and a second frequency value is determined based on the time interval between the third and fourth time-domain positions, where the third time-domain position is the time-domain position where the third correlation value reaches its maximum, and the fourth time-domain position is the time-domain position where the fourth correlation value reaches its maximum.

[0032] Based on the above scheme, the second frequency value can be determined by performing correlation operations on the correlation peaks obtained from the correlation operations on the first synchronization sequence and the first sampling sequence included in the local synchronization sequence, and on the correlation peaks obtained from the correlation operations on the second synchronization sequence and the second sampling sequence included in the local synchronization sequence. The second frequency value can be understood as the integer frequency offset included in the frequency deviation between the receiving device and the transmitting device. Thus, the receiving device can perform frequency synchronization based on the first frequency value and the second frequency value, reducing the complexity of frequency synchronization for the receiving device.

[0033] In conjunction with the second aspect, in some implementations of the second aspect, time synchronization is performed based on the third time domain position and the fourth time domain position.

[0034] Based on the above scheme, by using the time domain position corresponding to the correlation peak obtained by correlation operation of the first synchronization sequence and the first sampling sequence included in the local synchronization sequence, and the time domain position corresponding to the correlation peak obtained by correlation operation of the second synchronization sequence and the second sampling sequence included in the local synchronization sequence, the time deviation between the receiving device and the transmitting device can be determined, thereby enabling time synchronization.

[0035] In conjunction with the second aspect, in some implementations of the second aspect, the root index corresponding to the first synchronization sequence and the root index corresponding to the second synchronization sequence are different elements in the first set, which includes one or more root indices, and any two root indices among the multiple root indices are different.

[0036] Thirdly, a synchronization method is provided, applicable to a transmitting device. This transmitting device can be a network device, or a module, circuit, or chip that can be configured within the network device (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core, etc.), or a logic module or software capable of implementing some or all of the functions of the network device. Alternatively, the transmitting device can be a terminal device, or a module, circuit, or chip that can be configured within the terminal device (such as a chip or circuit, which can be a modem chip, also known as a baseband chip, or a SoC or SIP chip containing a modem core, etc.), or a logic module or software capable of implementing some or all of the functions of the terminal device, etc. This application does not limit this aspect.

[0037] The method includes: generating a synchronization signal based on a first synchronization sequence, the first synchronization sequence satisfying: The synchronization signal is sent for frequency synchronization; where x q (m) represents the first synchronization sequence, q represents the root index of the first synchronization sequence, N represents the length of the first synchronization sequence, and α is a real or complex number. The first synchronization sequence is represented as: and A linear combination of .

[0038] Based on the above scheme, by sending a synchronization signal generated by a synchronization sequence that can be represented as a ZC sequence and a conjugate sequence of the ZC sequence to the receiving device, the receiving device can perform sliding correlation operations in the subsequent frequency synchronization process based on the ZC sequence and the conjugate sequence of the ZC sequence, thereby reducing the complexity of frequency synchronization and improving the synchronization performance of the receiving device.

[0039] Fourthly, a synchronization method is provided, applicable to a transmitting device. This transmitting device can be a network device, or a module, circuit, or chip that can be configured within the network device (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core, etc.), or a logic module or software capable of implementing some or all of the functions of the network device. Alternatively, the transmitting device can be a terminal device, or a module, circuit, or chip that can be configured within the terminal device (such as a chip or circuit, which can be a modem chip, also known as a baseband chip, or a SoC or SIP chip containing a modem core, etc.), or a logic module or software capable of implementing some or all of the functions of the terminal device, etc. This application does not limit this aspect.

[0040] The method includes: generating a first synchronization signal based on a first synchronization sequence, the first synchronization sequence satisfying: A second synchronization signal is generated based on a second synchronization sequence, wherein the first synchronization sequence satisfies: The first synchronization signal and the second synchronization signal are transmitted for frequency synchronization; wherein, x q1 (m) represents the first synchronization sequence, q1 represents the root index of the first synchronization sequence, and x q2 (m) represents the second synchronization sequence, q2 represents the root index of the second synchronization sequence, the values ​​of q1 and q2 are different, and N represents the length of the first synchronization sequence and the second synchronization sequence.

[0041] Based on the above scheme, by sending a first synchronization signal and a second synchronization signal generated by two ZC sequences with different root indices (i.e., the first synchronization sequence and the second synchronization sequence) to the receiving device, the terminal device can perform sliding correlation operations in the subsequent frequency synchronization process based on the first synchronization sequence and the second synchronization sequence, thereby reducing the complexity of frequency synchronization and improving the synchronization performance of the terminal device.

[0042] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the first synchronization signal is transmitted on a first time-frequency resource; the second synchronization signal is transmitted on a second time-frequency resource; wherein the time domain position or frequency domain position corresponding to the first time-frequency resource and the second time-frequency resource are different.

[0043] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the root index corresponding to the first synchronization sequence is an element in a first set, which includes one or more root indices, and any two root indices among the plurality of root indices are different.

[0044] Fifthly, a communication apparatus is provided for performing the methods of the first to fourth aspects and any possible implementation thereof. Specifically, the apparatus may include units and / or modules for performing the methods of the first to fourth aspects and any possible implementation thereof, such as processing units and / or communication units.

[0045] In one implementation, the device is a communication device (such as a terminal device or a network device). When the device is a communication device, the communication unit can be a transceiver or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0046] In another implementation, the device is a chip, chip system, or circuit for communication equipment (such as terminal equipment or network equipment). When the device is a chip, chip system, or circuit for communication equipment, the communication unit can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing unit can be at least one processor, processing circuit, or logic circuit.

[0047] A sixth aspect provides a communication device, comprising: at least one processor for executing a computer program or instructions stored in a memory to perform the method in any of the possible implementations of the first to fourth aspects described above. Optionally, the device further includes a memory for storing the computer program or instructions; correspondingly, the at least one processor is configured to execute the computer program or instructions in the memory. Optionally, the device further includes a communication interface coupled to the processor, which can be used to input information to the processor or output information from the processor. Optionally, the processor reads the computer program or instructions from the memory through the communication interface.

[0048] In one implementation, the device is a communication device (such as a terminal device or a network device).

[0049] In another implementation, the device is a chip, chip system, or circuit for communication equipment (such as terminal equipment or network equipment).

[0050] In a seventh aspect, a processor is provided for performing the methods provided in the first to fourth aspects described above.

[0051] Unless otherwise specified, or if it does not contradict its actual function or internal logic in the relevant description, the transmission and acquisition / reception operations involved in the processor can be understood as processor output and reception, input and other operations, or as transmission and reception operations performed by radio frequency circuits and antennas. This application does not limit them in this regard.

[0052] Eighthly, a computer-readable storage medium is provided, on which a computer program or instructions are stored, which, when executed on a communication device, cause the communication device to perform the methods provided in the first to fourth aspects.

[0053] A ninth aspect provides a computer program product comprising a computer program or instructions for performing the methods of any of the possible implementations of the first to fourth aspects. In other words, when the computer program product is run on a computer, it causes the computer to perform the methods provided in the first to fourth aspects.

[0054] In a tenth aspect, a chip is provided, the chip including a processor and a communication interface, wherein the processor reads instructions from a memory through the communication interface and executes the methods provided in the first to fourth aspects above.

[0055] Optionally, as one implementation, the chip further includes a memory storing computer programs or instructions, and a processor for executing the computer programs or instructions in the memory. When the computer programs or instructions are executed, the processor is used to perform the methods provided in the first to fourth aspects above.

[0056] Eleventhly, a communication system is provided, including the aforementioned receiving end device (such as a terminal device, or a network device) and transmitting end device (such as a network device, or a terminal device). Attached Figure Description

[0057] Figure 1 This is a schematic diagram of a communication system applicable to this application.

[0058] Figure 2 This is a schematic diagram of another communication system applicable to this application.

[0059] Figure 3 This is a schematic diagram illustrating an application scenario applicable to this application.

[0060] Figure 4 This is a schematic diagram of a synchronization signal transmission process.

[0061] Figure 5 This is a schematic diagram of a frequency sweep and sliding correlation process.

[0062] Figure 6 This is a schematic diagram of obtaining correlation peaks through a sliding correlation process.

[0063] Figure 7 This is a schematic flowchart of a communication method 700 provided in this application.

[0064] Figure 8 This is a schematic diagram showing the temporal position relationship between integer frequency offset and correlation peak.

[0065] Figure 9 This is a schematic flowchart of a communication method 900 provided in this application.

[0066] Figure 10 This is a schematic diagram of a time-frequency resource distribution provided in this application.

[0067] Figure 11 This is a schematic block diagram of a communication device 1100 provided in this application.

[0068] Figure 12 This is a schematic diagram of another communication device 1200 provided in this application.

[0069] Figure 13 This is a schematic diagram of a chip system 1300 provided in this application. Detailed Implementation

[0070] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0071] The technical solutions provided in this application can be applied to various communication systems, such as: Long Term Evolution (LTE) technology, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, 5G or NR systems and future communication systems, vehicle-to-everything (V2X) connectivity, where V2X can include vehicle-to-network (V2N), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P), etc., long term evolution-vehicle (LTE-V) communication, vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), long term evolution-machine (LTE-M) communication, machine-to-machine (M2M), etc. The method provided in this application can also be applied to non-terrestrial network (NTN) communication systems, or scenarios where NTN and terrestrial network (TN) are integrated. The NTN system can be an NTN system integrated with 4G, 5G, or any future generation of communication systems, such as NR NTN, IoT NTN, etc. The NTN communication system can be, for example, a satellite communication system, or it can include unmanned aerial vehicles (UAVs), high altitude platform stations (HAPS), and other aerial access network equipment; this application does not limit this.

[0072] Figure 1 This is a schematic diagram of a communication system applicable to an embodiment of this application. For example... Figure 1 As shown, the communication system 10 includes a radio access network (RAN) 100 and a core network (CN) 200. RAN 100 includes at least one RAN node (e.g., Figure 1 110a and 110b (collectively referred to as 110) and at least one terminal (such as Figure 1RAN100, denoted as RAN100, comprises RAN nodes 120a-120j, collectively referred to as RAN120. RAN100 may also include other RAN nodes, such as wireless relay equipment and / or wireless backhaul equipment. Figure 1 (Not shown in the image). Terminal 120 is connected to RAN node 110 wirelessly. RAN node 110 is connected to CN 200 wirelessly or via wired connection. The core network equipment in CN 200 and RAN node 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and radio access network logical functions.

[0073] RAN 100 can be used for the third-generation partner program (3 rd Cellular systems related to the Generation Partnership Project (3GPP), such as fourth-generation (4G) cellular systems. th RAN 100 can be a generation (4G) mobile communication system, a 5G mobile communication system, or a future-oriented evolution system. RAN 100 can also be an open radio access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi / WIFI) system. RAN 100 can also be a communication system that integrates two or more of the above systems.

[0074] RAN node 110, sometimes also referred to as access network equipment, network equipment, RAN entity, or access node, constitutes part of the communication system and is used to help terminals achieve wireless access. Multiple RAN nodes 110 in this communication system can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal 120 are relative, for example... Figure 1 Network element 120i can be a helicopter or a drone, and it can be configured as a mobile base station. For terminals 120j that access RAN 100 through network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal. RAN node 110 and terminal 120 are sometimes referred to as communication devices, for example... Figure 1 Network elements 110a and 110b can be understood as communication devices with base station functions, while network elements 120a-120j can be understood as communication devices with terminal functions.

[0075] In one possible scenario, a RAN node can be a base station (BS), an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a base station in a future mobile communication system, or an access node in a WiFi system, etc. A RAN node can also be a macro base station (such as...) Figure 1 110a), micro base stations or indoor stations (such as Figure 1 The RAN node can be a relay node or donor node (as defined in 110b), or a wireless controller in a CRAN scenario. RAN nodes can also be satellites (or satellite base stations) or high altitude platform stations (HAPS), or base station equipment mounted on satellites / HAPS. Satellites can include at least one of the following: geostationary earth orbit (GEO) satellites or non-geostationary earth orbit (NGEO) satellites. Non-geostationary earth orbit satellites can include at least one of the following: medium earth orbit (MEO) satellites or low earth orbit (LEO) satellites. There are no restrictions here. RAN nodes can also be gateway stations (or ground stations, earth stations, signaling stations, gateways, or gateway stations). Optionally, RAN nodes can also be servers, wearable devices, vehicles, or vehicle-mounted equipment. For example, the access network equipment in V2X technology can be a roadside unit (RSU). All or part of the functions of the RAN node in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (e.g., a cloud platform). The RAN node may also be equipped with communication modules, circuits, or chips that perform corresponding communication functions. The RAN node may also be configured with program instructions for performing corresponding communication functions and corresponding program instructions. The RAN node in this application can also be a logical node, logical module, or software capable of implementing all or part of the RAN node functions.

[0076] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, with different RAN nodes each implementing some of the base station's functions. For example, RAN nodes can be CUs, DUs, CUs (control plane, CP), CUs (user plane, UP), or radio units (RUs). CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0077] In different systems, CU (including open CU-CP (O-CU-CP) and open CU-UP (O-CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called an open central unit (O-CU), DU can also be called an open distributed unit (O-DU), and RU can also be called an open radio unit (O-RU). For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0078] Terminal 120 can be a device or module that accesses the aforementioned communication system and has corresponding communication functions. Terminal equipment can also be called a terminal, user equipment (UE), mobile station, mobile terminal, etc. Terminal equipment can be a device that provides voice and / or data, such as a handheld device or vehicle-mounted device with wireless connectivity. Terminal equipment can also be a communication module with satellite communication capabilities, a satellite phone or its components, or a satellite communication terminal, such as a very small aperture terminal (VSAT) (commonly referred to as a VSAT terminal), a portable station, a fixed station, or a vehicle-mounted or airborne satellite communication terminal. It should be understood that a satellite communication terminal can act as a micro base station to further provide data interfaces to the accessing user equipment. Currently, examples of terminals include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, wearable devices, terminal devices in 5G networks, or future public land mobile communication networks. Terminal devices in a network (PLMN), Wi-Fi stations (STAs), etc. This application does not limit this to specific examples.

[0079] Terminal devices can also be terminal devices in an IoT system, also known as IoT nodes. IoT is an important component of future information technology development. Its main technical characteristic is connecting objects to networks through communication technologies, thereby realizing an intelligent network that enables human-machine interaction and machine-to-machine interaction. Connections can be made using broadband or narrowband technologies. IoT technology, for example, can achieve massive connectivity, deep coverage, and low power consumption at the terminal level through narrowband (NB) technology.

[0080] In addition, terminal devices may also include sensors such as smart printers, train detectors, and gas stations. Their main functions include collecting data (for some terminal devices), receiving control information and downlink data from network devices, and sending electromagnetic waves to transmit uplink data to network devices.

[0081] Terminal devices can also be wearable devices. Wearable devices, also known as wearable smart devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not just hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are feature-rich, large in size, and can achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those that focus on a specific application function and require the use of other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0082] In this embodiment, the device for implementing the functions of the terminal device can be the terminal device itself, or it can be any device capable of supporting the terminal device in implementing those functions, such as a chip system. This device can be installed in or used in conjunction with the terminal device. In this embodiment, the chip system can be composed of chips or may include chips and other discrete components. This embodiment only uses the terminal device as an example to illustrate the device for implementing the functions of the terminal device, and does not constitute a limitation on the solution of this embodiment.

[0083] RAN 100 and terminal 120 can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the scenarios in which RAN 100 and terminal 120 are located.

[0084] CN 200 can be a 5G core network or an evolved 5G core network. Taking a 5G core network as an example, CN 200 includes access and mobility management (AMF) network elements responsible for mobility management and access management services; session management (SMF) network elements responsible for session management; user plane (UPF) network elements responsible for user plane packet routing and forwarding and quality of service (QoS) control; and policy control (PCF) network elements. These core network elements can operate independently or be combined to implement certain control functions; for example, AMF, SMF, and PCF can be combined into a single core network device.

[0085] It should be understood that the above naming is defined solely for the purpose of distinguishing different functions and should not constitute any limitation on this application. This application does not preclude the possibility of using other naming conventions in 5G networks and other future networks. For example, in future networks, some or all of the above-mentioned network elements may use the terminology from 5G, or they may use other names, etc.

[0086] As an example, a RAN node can be a satellite base station, as described below. Figure 2 illustrate.

[0087] Figure 2 This is a schematic diagram of a communication system applicable to embodiments of this application. For example... Figure 2 As shown in (a) and (b), satellite base stations provide communication services to terminals. For example, a satellite base station transmits downlink data to a terminal, where the data is encoded using channel coding, and the channel-coded data is then transmitted to the terminal after constellation modulation. Similarly, a terminal transmits uplink data to a satellite base station; the uplink data can also be encoded using channel coding, and the encoded data is then transmitted to the satellite base station after constellation modulation. Additionally, as... Figure 2 As shown in (b), satellite base stations can also communicate with ground base stations, meaning that satellites can act as both base stations and terminals.

[0088] In this application, "satellite" can refer to unmanned aerial vehicles (UAVs), hot air balloons, low-Earth orbit (LEO) satellites, medium-Earth orbit (MEO) satellites, high-Earth orbit (HEO) satellites, etc. "Satellite" can also refer to non-terrestrial base stations or non-terrestrial equipment, etc.

[0089] It should be understood that this application can be applied to scenarios involving communication between network devices. Figure 2The scenario shown in (b) can also be seen as an example of network device communication, where both the satellite and the base station can be considered as a network device.

[0090] As another implementation method, this application can be applied to Internet of Things (IoT) communication systems.

[0091] Figure 3 This is a schematic diagram illustrating an IoT wireless screen projection method applicable to embodiments of this application. For example... Figure 3 As shown, a terminal device (such as a smartphone) establishes a network connection with a television. The smartphone transmits the content that needs to be projected onto the television to the television. After receiving the content transmitted by the smartphone, the television displays the content on its screen.

[0092] It should be understood that this application can also be applied to scenarios involving communication between terminal devices. Figure 3 The screen mirroring scenario shown can also be seen as an example of communication between terminal devices, where both smartphones and televisions can be considered as terminal devices.

[0093] It should be understood that the above system application scenarios are merely examples, and this application can also be applied to other scenarios, which are not listed here.

[0094] To facilitate understanding of the embodiments of this application, the terminology and background involved in this application will be briefly introduced below.

[0095] 1. Time and frequency resources

[0096] In the embodiments of this application, data or information can be carried using time-frequency resources. Time-frequency resources can include resources in the time domain and resources in the frequency domain. In the time domain, time-frequency resources can include one or more time-domain units (also referred to as time units, time cells, etc.); in the frequency domain, time-frequency resources can include one or more frequency-domain units.

[0097] In this context, a time-domain unit can be one or more symbols (such as orthogonal frequency division multiplexing (OFDM) symbols), a slot, a mini-slot, or a subframe. A slot can consist of 7 or 14 symbols; a mini-slot can include at least one symbol (e.g., 2, 7, or 14 symbols, or any number of symbols less than or equal to 14); and the duration of a subframe in the time domain can be 1 millisecond (ms).

[0098] It should be understood that the time-domain cell sizes listed above are only for the convenience of understanding the scheme of this application and do not constitute a limitation on the scope of protection of this application. The time-domain cell sizes mentioned above can be other values ​​and are not limited thereto.

[0099] A frequency domain unit can be a resource block (RB), a subcarrier, a resource block group (RBG), a predefined subband, a precoding resource block group (PRG), a bandwidth part (BWP), a resource element (RE) (also called a resource unit or resource particle), a carrier, or a serving cell, etc.

[0100] 2. Zadoff-chu (ZC) sequence

[0101] In wireless communication systems, ZC sequences can be used to generate downlink synchronization signals, uplink random access sequences, reference signals, waveform signals, etc.

[0102] The expression for the ZC sequence is shown in formula (1):

[0103]

[0104] Where, N zc It can represent the period of the ZC sequence; q represents the root index (or root value) of the ZC sequence, and the value of q is related to N. zc Coprime, 1≤q <N ZC ;x q (m) is a ZC sequence with root q.

[0105] ZC sequences can be used as synchronization sequences to help the receiver synchronize signals. For example, ... Figure 4 As shown, in an orthogonal frequency division multiplexing (OFDM) system, OFDM symbols are used to transmit synchronization sequences. Figure 4 The diagram shows the resources for 5 OFDM symbols, where the middle OFDM symbol can be used to transmit ZC sequences. Before transmitting the ZC sequence, the transmitter generates a sequence of length N. zcThe ZC sequence is mapped onto a subcarrier, and then subjected to an inverse fast Fourier transform (IFFT) and the addition of a cyclic prefix (CP) to obtain the OFDM symbol in the time domain.

[0106] At the receiving end, a sliding correlation operation is required to achieve synchronization. Specifically, the receiving end knows the ZC sequence sent by the transmitting end before synchronization. Then, it uses the local ZC sequence to generate a time series and performs a sliding correlation operation with the received signal to achieve synchronization. For details, please refer to the description of the sliding correlation operation below.

[0107] In the communication scenarios described above, synchronization between the sender and receiver is a crucial step in establishing a connection. Synchronization can include uplink synchronization and downlink synchronization. For example, in downlink synchronization, the terminal device can achieve synchronization by detecting the primary synchronization signal (PSS) and the secondary synchronization signal (SSS); in uplink synchronization, the network device can achieve synchronization by detecting the preamble transmitted in the physical random access channel (PRACH). Synchronization can also include time synchronization and frequency synchronization. Time synchronization refers to the receiver finding the starting position of the transmitted signal in the time domain, such as the boundary of the transmitted signal's time slot, so that the receiver can process the received signal slot by slot. During signal transmission and reception, the sender uses a specific carrier frequency to transmit the signal, for example, a carrier frequency of fc = 2 GHz. The receiver downconverts the signal on the carrier frequency to baseband for signal processing. In the downconversion process, the receiver can locally generate a carrier signal to convert the signal to baseband, for example, the frequency of this carrier signal is fc = 2 GHz. Frequency synchronization refers to the process of aligning the frequency of a local carrier signal generated at the receiving end with the carrier frequency of the signal transmitted at the transmitting end. During frequency synchronization, the local carrier signal is generated by a local crystal oscillator (LoU). However, the frequency of the local carrier signal often deviates from the carrier frequency used by the transmitting end. For example, the crystal oscillator's frequency may shift due to different temperatures, or the signal may experience Doppler shift when the transmitting / receiving end is moving at high speed. These factors can cause frequency discrepancies between the two ends. This frequency discrepancy needs to be corrected during frequency synchronization.

[0108] The following example uses a network device as the sender and a terminal device as the receiver to illustrate the process of time synchronization and frequency synchronization (i.e., downlink synchronization).

[0109] In downlink synchronization, the network side (such as a base station or network device) is typically used as the time and frequency reference, requiring the terminal device to synchronize with the network device's time and frequency. During synchronization, the network device can periodically send a synchronization reference signal (also called a synchronization signal) to the terminal device. Based on the received synchronization reference signal, the terminal device estimates the current time and frequency deviations using correlation algorithms in the frequency and time domains, and after compensating for these deviations, completes the time and frequency synchronization.

[0110] The aforementioned synchronization reference signal can take different forms and designs in different systems. For example, in a 5G NR system, the synchronization signal can be a PSS. The synchronization signal can be generated from a sequence, and the selected sequence usually possesses good autocorrelation and cross-correlation properties. Commonly used sequences include ZC sequences, Gold sequences, and M sequences. Here, the sequence used for the synchronization signal is referred to as the synchronization sequence, and denoted as x. sync (n).

[0111] like Figure 5 As shown in (a), the network device periodically sends a synchronization signal. If the system is an OFDM waveform system, the network device can map the synchronization sequence onto a set of subcarriers, generate an OFDM time-domain signal (i.e., synchronization signal) after IFFT, and transmit it through the antenna port after digital-to-analog conversion, up-conversion, and power amplification.

[0112] At the receiving end, since the receiver knows how the transmitter's synchronization sequence was generated, it can use a local synchronization sequence to synchronize the frequency and time with the received signal. Common practices include frequency sweeping and sliding correlation. When time and frequency are synchronized, a significant correlation peak will appear. The receiver can then use the time and frequency of the most significant correlation peak to complete time and frequency synchronization, as detailed below.

[0113] After receiving the synchronization signal, the receiving end performs analog-to-digital sampling on the synchronization signal to obtain a sampled sequence, denoted as r(n). r(n) contains a synchronization sequence, denoted as rs. sync (n), 0 <n≤N sym N symThis represents the number of sampling points in the analog-to-digital conversion (ADC) sampling. It should be understood that before synchronization is complete, although the receiver does not know the exact position and frequency deviation of the synchronization sequence within the received synchronization signal, the receiver knows the numerical value of the synchronization sequence, i.e., x. sync (n), so the receiver can locally deduce the sequence after the synchronization sequence has undergone IFFT and sampling, denoted as s. sync (n).

[0114] The specific process of time and frequency synchronization can be accomplished through frequency sweeping and sliding correlation, such as... Figure 5 As shown in (b). Frequency sweeping can refer to selecting frequency points one by one within the frequency deviation range and performing frequency compensation on the local carrier signal according to a certain step size. When the compensation frequency is equal to the frequency deviation, there will be no frequency deviation between the frequency of the compensated local carrier signal and the carrier of the transmitted synchronization signal.

[0115] For example, suppose the maximum deviation of the local crystal oscillator of the terminal device is [-F]. max F max If the sweep frequency is [-21kHz, 21kHz], then frequency compensation (or frequency offset compensation) can be performed within this range in steps of a certain size (e.g., 7kHz). This means the sweep frequency Δf ∈ {-21, -14, -7, 0, 7, 14, 21}kHz. Frequency compensation can refer to multiplying each sweep frequency by a frequency compensation sequence, for example... Among them, T s This represents the time interval between two adjacent sampling points, and can be simply referred to as the sampling point interval. If the frequency offset is the same as or very close to the current sweep frequency, then the frequency offset between the compensated local carrier signal and the received synchronization sequence will be very low.

[0116] For each frequency sweep, after frequency compensation, a sliding correlation process is performed. During the sliding correlation process, the receiver can use a sliding window to truncate the sampled sequence of the received signal. For example, the receiver can use a sliding window to slide from the beginning of the received signal, moving one sampling point at a time, completing one truncation and correlation operation each time.

[0117] For example, during the l-th sliding process, the receiver captures a signal of length N according to the sliding window. sym The expression for the signal intercepted at each sampling point is r. l (n)=r(l+n),0 <n≤N sym Then, the captured signal is correlated with the local synchronization sequence, that is... This represents the conjugate of the locally calculated synchronization sequence. Thus, each sliding sampling point yields a correlation value C(l). If the frequency sweep uses frequency to compensate for frequency deviation, the correlation value reaches its maximum when the sliding window coincides with the synchronization sequence. Significant correlation peaks will appear.

[0118] Figure 6 The diagram shows a correlation peak obtained from the sliding correlation process. Furthermore, when the sweep frequency and frequency offset differ significantly, even with time alignment, a correlation peak may not appear. For example, as... Figure 6 As shown, when the sweep frequency is Δf = 0 kHz, a significant correlation peak appears; when the sweep frequency is Δf = 7 kHz or Δf = -7 kHz, the compensated frequency is close to the frequency deviation, and the correlation peak is still visible, but the peak value is reduced; when Δf = 14 kHz or Δf = -14 kHz, the correlation peak cannot be detected because the compensated frequency differs greatly from the actual frequency deviation.

[0119] The above describes the downlink frequency and time synchronization process. A similar process is required for uplink transmission to achieve time and frequency synchronization. This process typically occurs during the terminal's random access process. At this time, the network allocates certain time-frequency resources as random access channel occasions (ROs). When the terminal device needs to access the network, it sends a random access sequence within the RO, which can be considered a preamble. The preamble can be implemented using different sequences, such as ZC sequences and M sequences. When the network receives the preamble, it can detect and determine the existing frequency and time deviations, and notify the terminal device to change its transmission frequency and transmission time via downlink signaling, thereby ensuring that the time and frequency of the signal arriving at the network side are synchronized.

[0120] With the evolution of communication technology, mobile communication scenarios are becoming increasingly complex. In some cases, significant frequency deviations may occur between the transmitter and receiver, significantly increasing the complexity of frequency synchronization. For example, in satellite communication, satellites move relatively quickly relative to the Earth. A satellite with an orbital altitude of 600km moves at approximately 7.5km / s relative to the ground, resulting in a significant Doppler shift (Doppler shift refers to the phenomenon where the frequency of the received signal shifts when there is a relative velocity between the transmitter and receiver). For instance, if a satellite with an orbital altitude of 600km uses a 2GHz carrier frequency to transmit signals, the Doppler shift of the received signal will be approximately in the range of [-42kHz, 42kHz]. Due to the Doppler shift, the maximum frequency deviation range between the transmitter and receiver becomes significantly larger. As mentioned earlier, assuming the maximum deviation range of the local crystal oscillator of the terminal device is [-F...]...max F max ] = [-21kHz, 21kHz]. If the same settings are used in a satellite communication system, the frequency error range also needs to consider the Doppler frequency offset, so the possible frequency error range is [-F]. max F max ] = [-63kHz, 63kHz]. In this case, if we still follow... Figure 5 The frequency sweeping method shown requires frequency compensation and sliding correlation within a larger sweeping range, such as Δf∈{-63,-56,-49,-42,-35,-21,-14,-7,0,7,14,21,35,42,49,56,63}, which greatly increases the search range and leads to a significant increase in synchronization complexity.

[0121] To address the issue of large initial frequency deviations during time and frequency synchronization, satellite communication systems can utilize ephemeris and positioning information to predict satellite Doppler frequency offsets, thereby reducing the number of searches. However, this approach requires terminal devices to frequently update ephemeris information and perform positioning, increasing their power consumption. Secondly, this approach also requires terminal devices to possess ephemeris information acquisition capabilities and positioning modules, hindering scalability and increasing manufacturing costs. In particular, some low-cost terminal devices, such as IoT devices, may lack positioning modules, making Doppler frequency offset prediction and compensation impossible. Furthermore, these low-cost devices themselves may introduce significant frequency deviations; for example, their low-cost crystal oscillators may have lower accuracy, all of which significantly increase the complexity of synchronization.

[0122] In view of this, this application provides a synchronization method and apparatus to reduce the complexity of frequency synchronization and improve the efficiency of synchronization when the range of synchronization frequency deviation is large.

[0123] Figure 7 The diagram shown is a schematic representation of a communication method 700 provided in this application. Method 700 may include the following steps.

[0124] S710, the transmitting device sends a synchronization signal to the receiving device. Correspondingly, the receiving device receives the synchronization signal.

[0125] The synchronization signal is generated based on a first synchronization sequence, which can be represented as a linear combination of a first ZC sequence and a conjugate sequence of the first ZC sequence.

[0126] For example, the expression for the first synchronization sequence is shown in formula (2):

[0127]

[0128] wherein the x q (m) represents the first synchronization sequence, 0≤m<N, and N represents the length of the first synchronization sequence; q represents the root index of the first synchronization sequence; the value range of α may be a real number or a complex number.

[0129] The first synchronization sequence can also be expressed as (an example of the first ZC sequence) and (i.e., the conjugate sequence of the first ZC sequence).

[0130] It should be understood that the above expression of the first synchronization sequence is only an example, and does not constitute a limitation on the present application. For example, the expression of the first synchronization sequence may also be an equivalent deformation of formula (2).

[0131] In a possible implementation, the transmitting end apparatus maps the first synchronization sequence to a set of subcarriers, generates an OFDM time-domain signal after IFFT, and transmits the time-domain signal through an antenna port after digital-to-analog conversion, up-conversion, and power amplification (i.e., transmits the synchronization signal).

[0132] Exemplarily, the synchronization signal in the present application may be a PSS in an LTE system, a PRACH preamble, an SSB in an NR system, a PRACH preamble, or may also be a Narrowband Primary Synchronization Signal (NPSSS) in an NB-IoT system, a PRACH preamble, and the specific form of the synchronization signal is not limited.

[0133] It should be understood that the receiving end apparatus in the present application may be a terminal device, and the transmitting end apparatus may be a network device; alternatively, the receiving end apparatus may be a network device, and the transmitting end apparatus may be a terminal device, that is, the embodiments of the present application may be applied to downlink synchronization, and may also be applied to uplink synchronization. The terminal device may also be replaced by a component of the terminal device (such as a chip or a chip system or a circuit or a communication module), or may be replaced by a logic module or software that can implement part or all of the functions of the terminal device. The network device may also be replaced by a component of the network device (such as a chip or a chip system or a circuit or a communication module), or may be replaced by a logic module or software that can implement part or all of the functions of the network device, and the like.

[0134] S720: The receiving end apparatus performs frequency synchronization according to the synchronization signal.

[0135] That is, the receiving device performs frequency compensation on the local carrier signal (an example of the first carrier signal) based on the reception of the synchronization signal, so that the frequency of the local carrier signal is equal to or approximately equal to the carrier frequency of the transmission of the synchronization signal (denoted as f0).

[0136] The local carrier signal can be used to down-convert the synchronization signal. For example, down-conversion can refer to the process of mixing the received synchronization signal with the local carrier signal to convert the center frequency of the high-frequency signal to zero frequency (baseband). Down-conversion can also be called mixing, or radio frequency to baseband conversion, etc. The specific down-conversion process can be found in existing descriptions and will not be repeated here.

[0137] For example, the receiving device performs down-conversion processing on the synchronization signal based on the local carrier signal to obtain a baseband signal, and performs frequency synchronization based on the sampling sequence obtained by sampling the baseband signal.

[0138] The frequency of the local carrier signal is obtained by adjusting a first frequency value based on the carrier frequency f0 of the synchronization signal transmitted by the transmitting device. This first frequency value can be understood as a frequency compensation value; that is, the frequency of the local carrier signal is obtained by compensating f0 with this first frequency value. This first frequency value belongs to a first frequency range, which is less than or equal to the subcarrier spacing corresponding to the subcarrier transmitting the synchronization signal.

[0139] As one possible implementation, the receiving device selects a frequency compensation value within a frequency deviation range less than or equal to the subcarrier interval to compensate the local carrier signal. For example, the receiving device selects multiple frequency compensation values ​​within the frequency deviation range with a certain step size, and sequentially selects a frequency compensation value from the multiple frequency compensation values ​​to compensate f0, wherein the first frequency value is one of the multiple frequency compensation values.

[0140] Taking a subcarrier spacing of 15kHz corresponding to the subcarrier transmitting the synchronization signal, and the size of the first frequency range being one subcarrier spacing as an example, the receiving device can determine multiple frequency compensation values ​​within the first frequency range in steps of 7kHz, such as a frequency compensation value Δf∈{-7,0,7}kHz. Then the first frequency value can be one of -7kHz, 0kHz, and 7kHz.

[0141] Specifically, the receiving device can perform down-conversion processing on the synchronization signal based on the local carrier signal to obtain a baseband signal, and after sampling the baseband signal to obtain a sampling sequence, further determine a second frequency value based on the sampling sequence and the second synchronization sequence; the receiving device performs frequency synchronization based on the second frequency value.

[0142] The second synchronization sequence is generated by the receiving device; that is, the second synchronization sequence can be understood as a local synchronization sequence. The second synchronization sequence includes the first ZC sequence and its conjugate sequence. Alternatively, the second synchronization sequence includes two synchronization sequences (i.e., the first ZC sequence and its conjugate sequence), and a linear combination of these two synchronization sequences can be represented as the first synchronization sequence.

[0143] As one possible implementation, the receiving device determines the second frequency value through a sliding correlation process.

[0144] For example, the receiving device sequentially extracts a portion of the sampled sequence through a sliding window, and performs correlation operations on each extracted portion of the sampled sequence with the second and third sequences to obtain a first correlation value and a second correlation value. That is, the receiving device can obtain two correlation values ​​each time it slides the sliding window. The receiving device determines the second frequency value based on the time interval between the first time domain position and the second time domain position.

[0145] The specific process of performing correlation operations between one sequence and another can be referred to the previous description and will not be repeated here. The second sequence can be the time-domain sequence corresponding to the first ZC sequence, and the third sequence can be the time-domain sequence corresponding to the conjugate sequence of the first ZC sequence. For example, the second sequence is the time-domain sequence obtained by performing IFFT on the first ZC sequence, and similarly, the third sequence can be the time-domain sequence obtained by performing IFFT on the conjugate sequence of the first ZC sequence.

[0146] The first time-domain location can be the time-domain location where the first correlation value reaches its maximum (or the first correlation peak appears), or the first time-domain location can be a time-domain location range within which the first correlation peak appears. Similarly, the second time-domain location can be the time-domain location where the second correlation value reaches its maximum (or the second correlation peak appears) or a time-domain location range.

[0147] It is understandable that the receiving device can obtain a first correlation value and a second correlation value each time it slides the sliding window. When the sampled sequence captured by the sliding window is the first synchronization sequence, the first correlation value and the second correlation value reach their maximum.

[0148] In this application, since the local synchronization sequence (second synchronization sequence) of the receiving device includes two sequences, one of which is the conjugate sequence of the other, if the first frequency value cancels out the frequency deviation between the transmitting and receiving devices, then when the sliding window coincides with the first synchronization sequence, the first time domain position is the same as the second time domain position; conversely, if the first frequency value does not cancel out the frequency deviation between the transmitting and receiving devices, then when the sliding window coincides with the first synchronization sequence, the first time domain position is different from the second time domain position. Thus, the receiving device can determine the second frequency value based on the first and second time domain positions. The specific method by which the receiving device determines the second frequency value based on the first and second time domain positions can be referred to formulas (4) and (5) below.

[0149] Alternatively, if, during the sliding window process, the time domain position where the first correlation value reaches its maximum is the same as the time domain position where the second correlation value reaches its maximum, then the first frequency value can be considered to have offset the frequency deviation between the carrier frequency of the transmitting device transmitting the first synchronization signal and the frequency of the local carrier signal of the receiving device. In this case, the frequency synchronization performed by the receiving device based on the synchronization signal may only include frequency synchronization based on the first frequency value, without needing to determine the second frequency value and perform frequency synchronization based on the second frequency value.

[0150] Optionally, the method further includes: when the first time domain position and the second time domain position are different, the receiving device performs time synchronization based on the first time domain position and the second time domain position.

[0151] For example, the receiving device can determine the first moment as the time deviation compensation value, and adjust the time reference for receiving the signal from the transmitting device based on the time deviation compensation value. The first moment can be the intermediate moment between the first time domain position and the second time domain position.

[0152] Based on the above scheme, the frequency offset between the carrier frequency of the synchronization signal transmitted by the transmitting device and the local carrier signal of the receiving device can be decomposed into an integer frequency offset (second frequency value) and a fractional frequency offset (first frequency value). By performing frequency sweep within the fractional frequency offset range and determining the integer frequency offset based on the time domain position of the correlation peak obtained from the frequency sweep, the complexity of frequency synchronization can be reduced and the synchronization performance can be improved.

[0153] It should be understood that the aforementioned integer frequency offset can refer to a frequency offset whose magnitude is an integer multiple of the sub-carrier space (SCS), while the fractional frequency offset can refer to a frequency offset less than or equal to one sub-carrier space. For example, if the sub-carrier space of an OFDM system is 15kHz and the frequency offset range is 31kHz, then this frequency offset range can be decomposed into 30kHz and 1kHz, where 30kHz is the integer frequency offset (twice the sub-carrier space) and 1kHz is the fractional frequency offset (less than the sub-carrier space).

[0154] In this application, when using the ZC sequence as the synchronization sequence for sliding correlation, if the frequency offset between the carrier frequency of the synchronization signal transmitted by the transmitting device and the local carrier signal of the receiving device (hereinafter referred to as the frequency offset between the transmitting device and the receiving device) includes an integer frequency offset, it may cause a shift in the position of the correlation peak. For example... Figure 8 The image shows the correlation results for the ZC sequence under different integer frequency offsets. It can be seen that when the frequency offset is one or two subcarrier intervals, the temporal position of the correlation peak is offset from the temporal position when there is no frequency offset. Secondly, it is worth noting that the magnitude of this offset is related to the root index of the ZC sequence, such as... Figure 8 Figure (a) shows the magnitude of the correlation peak shift caused by different frequency offsets when the root index q = 1. Figure 8 Figure (a) shows the magnitude of the correlation peak shift caused by different frequency offsets when the root index q = 3. Furthermore, another property of ZC sequences is that if sequence 1 is a ZC sequence and sequence 2 is the conjugate of sequence 1, then under the same frequency offset, when using sequences 1 and 2 as synchronization sequences for sliding correlation, the temporal position shifts of the correlation peaks corresponding to the two sequences are the same in magnitude but opposite in direction.

[0155] It is understood that, in this application, the synchronization sequence corresponding to the synchronization signal transmitted by the transmitting device can be decomposed into a ZC sequence and its conjugate sequence. Taking the value of α as 1 as an example, that is, the synchronization sequence...

[0156] in, Let be a ZC sequence with root q (an example of the first ZC sequence), and It is its conjugate sequence.

[0157] Assume the frequency offset between the transmitting and receiving devices includes an integer frequency offset of n. Δ There are N subcarriers, and the sequence originally mapped on the N subcarriers is... With an integer frequency offset, for the receiving device, it's equivalent to the original synchronization sequence being mapped to a sequence separated by n. Δ On the subcarrier, that is, the synchronization sequence is expressed as formula (3):

[0158]

[0159] in, The phase rotation representing frequency results in a positional shift in the time domain. Therefore, frequency shift causes a shift in the time-domain position of the correlated peak, the magnitude of which can be... T os It can represent the duration of an OFDM symbol.

[0160] Therefore, in this application, if there is an integer frequency offset between the transmitting and receiving devices, the time-domain positions when the first correlation value reaches its maximum (or the first correlation peak appears) and the time-domain positions when the second correlation value reaches its maximum (or the second correlation peak appears) are two time-domain positions. The distance between the time-domain positions corresponding to these two correlation peaks is related to the magnitude of the integer frequency offset, thus allowing the magnitude of the integer frequency offset (i.e., the second frequency value) to be estimated based on the first and second time-domain positions.

[0161] For example, suppose there is an integer frequency offset of n between the transmitting and receiving devices. Δ f scs ,f scs n is the subcarrier spacing. Δ If the integer is positive, then the time offset corresponding to the first correlation peak is The time shift corresponding to the second correlation peak is The time interval between the two related peaks (i.e., the time interval between the first time domain position and the second time domain position) can be expressed as formula (4):

[0162]

[0163] From this, we can obtain n Δ :

[0164]

[0165] That is, the integer frequency offset can be obtained according to formula (5). After obtaining the integer frequency offset (i.e. the second frequency value), the fractional frequency offset (i.e. the first frequency value) estimated during the frequency sweep process can be combined to obtain the magnitude of the frequency deviation, thereby realizing frequency synchronization between the receiving device and the transmitting device.

[0166] Figure 9 The diagram shown illustrates another synchronization method 900 provided in this application. Method 900 may include the following steps.

[0167] S910, the transmitting device sends a first synchronization signal and a second synchronization signal to the receiving device. Correspondingly, the receiving device receives the first synchronization signal and the second synchronization signal.

[0168] The first synchronization signal is generated based on the first synchronization sequence; the second synchronization signal is generated based on the second synchronization sequence. The first and second synchronization sequences are ZC sequences, for example, the first synchronization sequence is a first ZC sequence and the second synchronization sequence is a second ZC sequence, and the root indices corresponding to the first and second ZC sequences are different.

[0169] For example, the expressions for the first synchronization sequence and the second synchronization sequence are shown in formulas (6) and (7), respectively:

[0170]

[0171] Where, m = 0, 1, ..., N ZC -1, N ZC q1 and q2 represent the lengths of the first and second synchronization sequences, respectively, and their values ​​are different.

[0172] Specifically, the transmitting device can transmit the first synchronization signal and the second synchronization signal on the first time domain resource and the second time domain resource respectively. Correspondingly, the receiving device receives the first synchronization signal on the first time-frequency resource and the second synchronization signal on the second time-frequency resource.

[0173] As an example, the first time-domain resource and the second time-domain resource can be arranged in a time-division manner.

[0174] For example, the transmitting device maps the first synchronization sequence onto a group of subcarriers, which in the time domain can correspond to time unit #1 (an example of the time domain position corresponding to the first time-frequency resource); the transmitting device maps the second synchronization sequence onto another group of subcarriers, which in the time domain can correspond to time unit #2 (an example of the time domain position corresponding to the second time-frequency resource), that is, the time domain positions corresponding to the first time-frequency resource and the second time-frequency resource are different, and the first time-frequency resource and the second time-frequency resource are arranged in a time-division manner.

[0175] Here, time unit #1 and time unit #2 can be two time units within a synchronization signal transmission period T, such as two adjacent time units within a period, for example... Figure 10 As shown in (a); or, time unit #1 and time unit #2 may be in different synchronization signal transmission cycles, for example, time unit #1 in the first synchronization signal transmission cycle and time unit #2 in the second synchronization signal transmission cycle. Time unit #1 and time unit #2 may have the same time domain position within a synchronization signal transmission cycle, such as... Figure 10 As shown in (b).

[0176] As another example, the first and second time-domain resources can be arranged in a frequency-division manner. For instance, the transmitting device maps the first synchronization sequence to one set of subcarriers and the second synchronization sequence to another set of subcarriers, where the two sets of subcarriers correspond to the same time-domain position but different frequency-domain positions. For example, ... Figure 10 As shown in (c).

[0177] It should be understood that the first synchronization signal and the second synchronization signal can be of the same type. For example, the first synchronization sequence and the second synchronization sequence can be PSS, PRACH preamble in the LTE system, or SSB, PARCH preamble in the NR system, or other synchronization signals. For details, please refer to the description in S710.

[0178] It should also be understood that the first synchronization signal mentioned above can be N1 synchronization signals, where N1 is a positive integer; the second synchronization signal can include N2 synchronization signals, where N2 is a positive integer. That is, the transmitting device can transmit one or more synchronization signals generated by the ZC sequence with root index q1, and can transmit one or more synchronization signals generated by the ZC sequence with root index q2, without limiting the number of the first and second synchronization signals.

[0179] The specific forms of the aforementioned transmitting and receiving devices can be found in the description in S710, and will not be repeated here.

[0180] S920, the receiving device performs frequency synchronization based on the first synchronization signal and the second synchronization signal.

[0181] That is, the receiving device performs frequency compensation on the local carrier signal (an example of the first carrier signal) based on the reception of the first synchronization signal and the second synchronization signal, so that the frequency of the local carrier signal is equal to or approximately equal to the carrier frequency (denoted as f0) of the first synchronization signal and / or the second synchronization signal.

[0182] The local carrier signal can be used to down-convert the first synchronization signal and / or the second synchronization signal. A description of the down-conversion process is provided in S720.

[0183] For example, the receiving device performs down-conversion processing on the first synchronization signal and the second synchronization signal based on the local carrier signal to obtain a first baseband signal and a second baseband signal, and performs frequency synchronization based on the first sampling sequence and the second sampling sequence obtained by sampling the first baseband signal and the second baseband signal respectively.

[0184] The frequency of the local carrier signal is obtained by adjusting a first frequency value based on the carrier frequency f0 of the synchronization signal transmitted by the transmitting device. This first frequency value belongs to a first frequency range, which is less than or equal to the subcarrier spacing corresponding to the subcarrier transmitting the synchronization signal. The method for determining this first frequency value can be found in the description in S720.

[0185] Furthermore, the receiving device can determine a second frequency value based on the first sampling sequence, the second sampling sequence, and the third synchronization sequence, and perform frequency synchronization based on the second frequency value.

[0186] The third synchronization sequence is generated by the receiving device; that is, the third synchronization sequence can be understood as a local synchronization sequence generated by the receiving device. The third synchronization sequence includes the first synchronization sequence and the second synchronization sequence. Alternatively, the receiving device generates two local synchronization sequences, one of which is the first synchronization sequence, and the other is the second synchronization sequence.

[0187] As one possible implementation, the receiving device determines the second frequency value through a sliding correlation process.

[0188] For example, the receiving device sequentially extracts a portion of the first sampling sequence through a first sliding window, and performs a correlation operation between each extracted portion of the sampling sequence and a fourth sequence to obtain a third correlation value. That is, each time the receiving device slides the first sliding window, it can obtain a correlation value based on a portion of the first sampling sequence and the fourth sequence. The receiving device sequentially extracts a portion of the second sampling sequence through a second sliding window, and performs a correlation operation between each extracted portion of the sampling sequence and a fifth sequence to obtain a fourth correlation value. That is, each time the receiving device slides the second sliding window, it can obtain another correlation value based on a portion of the second sampling sequence and the fifth sequence.

[0189] The receiving device can sequentially extract portions of the first sampling sequence through a first sliding window at the time-domain position corresponding to the first time-frequency resource, and can sequentially extract portions of the first sampling sequence through a second sliding window at the time-domain position corresponding to the second time-frequency resource. In other words, the time range covered by the first sliding window includes the time-domain position corresponding to the first time-frequency resource, and the time range covered by the second sliding window also includes the time-domain position corresponding to the second time-frequency resource. The fourth sequence can be the time-domain sequence corresponding to the first synchronization sequence, and the fifth sequence can be the time-domain sequence corresponding to the second synchronization sequence. For example, the fourth sequence is the time-domain sequence obtained by IFFT processing the first ZC sequence; similarly, the fifth sequence can be the time-domain sequence obtained by IFFT processing the second ZC sequence. The specific process of performing correlation operations between one sequence and another sequence can be referred to the previous description and will not be repeated here.

[0190] Furthermore, the receiving device determines the second frequency value based on the time interval between the third time-domain position and the fourth time-domain position. The third time-domain position can be the time-domain position where the third correlation value reaches its maximum (or where the third correlation peak occurs), or the third time-domain position belongs to a time-domain position range within which the third correlation peak occurs. Similarly, the fourth time-domain position can be the time-domain position where the fourth correlation value reaches its maximum (or where the fourth correlation peak occurs) or belong to a time-domain position range.

[0191] It is understood that the receiving device can obtain a third correlation value each time it slides the first sliding window. When the sampled sequence intercepted by the first sliding window is the first synchronization sequence, the third correlation value reaches its maximum (i.e., a third correlation peak appears). And, the receiving device can obtain a fourth correlation value each time it slides the second sliding window. When the sampled sequence intercepted by the second sliding window is the second synchronization sequence, the fourth correlation value reaches its maximum (i.e., a fourth correlation peak appears).

[0192] In this application, since the local synchronization sequence (third synchronization sequence) of the receiving device includes two sequences, and these are two ZC sequences with different root indices, if the first frequency value cancels out the frequency deviation between the transmitting and receiving devices, then when the first sliding window coincides with the first synchronization sequence and the second sliding window coincides with the second synchronization sequence, the third time domain position is the same as the fourth time domain position. Conversely, if the first frequency value does not cancel out the frequency deviation between the transmitting and receiving devices, then when the first sliding window coincides with the first synchronization sequence and the second sliding window coincides with the second synchronization sequence, the third time domain position is different from the fourth time domain position. Thus, the receiving device can determine the second frequency value based on the third and fourth time domain positions. The specific method by which the receiving device determines the second frequency value based on the third and fourth time domain positions can be found in formulas (8) and (9).

[0193] For example, suppose there is an integer frequency offset of n between the transmitting and receiving devices. Δ f scs ,f scs n is the subcarrier spacing. Δ If the integer is positive, then the time offset corresponding to the third correlation peak is The time shift corresponding to the fourth correlation peak is The interval between the two related peaks is:

[0194]

[0195] From this, we can obtain n Δ :

[0196]

[0197] That is, based on n Δ The second frequency value can be determined. After obtaining the integer frequency offset (i.e., the second frequency value), the fractional frequency offset estimated during the frequency sweep process (i.e., the first frequency value) can be combined to obtain the magnitude of the frequency deviation, thereby enabling frequency synchronization between the receiving device and the transmitting device.

[0198] It is understandable that if, during the sliding of the first and second sliding windows, the time domain position where the third correlation value reaches its maximum is the same as the time domain position where the fourth correlation value reaches its maximum, then the first frequency value can be considered to have offset the frequency deviation between the carrier frequency of the transmitting device transmitting the first synchronization signal and the frequency of the local carrier signal of the receiving device. In this case, the receiving device's frequency synchronization based on the synchronization signal may only include frequency synchronization based on the first frequency value, without needing to determine the second frequency value and perform frequency synchronization based on the second frequency value.

[0199] Optionally, the method further includes: when the third time domain position and the fourth time domain position are different, the receiving device performs time synchronization based on the third time domain position and the fourth time domain position. For example, the receiving device may determine a second moment as a time deviation compensation value, and adjust the time reference for receiving signals from the transmitting device based on the time deviation compensation value, wherein the second moment may be an intermediate moment between the third time domain position and the fourth time domain position.

[0200] The following describes how the root index of the synchronization sequence is selected in methods 700 and 900.

[0201] In one possible implementation, the root index of the synchronization sequence can be an element of a set of root indices (an example of a first set). This set of root indices can include multiple root indices, any two of which are different. By selecting different root indices from this set, neighboring cells can use different synchronization sequences (i.e., the synchronization sequence is determined based on different root indices), thereby reducing interference between neighboring cells.

[0202] For example, the set of root indexes may be predefined by the protocol or determined through negotiation between network devices, without limitation.

[0203] Optionally, when neighboring cells use different synchronization sequences (or determine the synchronization sequence based on different root indices), the network device can determine the root index used by the cell based on the cell's identity (ID).

[0204] For example, for the synchronization sequence in method 700, a first root index set can be agreed upon by the protocol, containing three elements Q = {1, 2, 3}. When neighboring cells use different root indices from this first root index set, the root index to be used can be determined based on the cell ID. For instance, a modulo operation can be performed on the cell ID with respect to a (where a is a positive integer, e.g., a = 3), and the result k is used to determine which root index to use. For example, k = mod(cellID, 3). If k = 0 after the modulo operation, then q = 1 is used; if k = 1, then q = 2 is used; and if k = 2, then q = 3 is used.

[0205] For example, for the synchronization sequence in method 900, a second root index set can be agreed upon by the protocol. This second root index set can include two subsets, denoted as subset #1 and subset #2, respectively. Subset #1 can be used to select the root index of the first synchronization sequence in method 900, and subset #2 can be used to select the root index of the second synchronization sequence in method 900.

[0206] In this subset, subsets #1 and #2 have no intersection. If subset #1 contains three sequences Q1 = {1, 2, 3} and subset #2 contains three sequences Q2 = {N-1, N-2, N-3}, then the second root index set can be represented as Q = Q1 ∪ Q2 = {1, 2, 3, N-1, N-2, N-3}. Similarly, adjacent cells can determine which two root indices from the two subsets to use based on their cell IDs. For example, a modulo operation is performed on the cell ID with respect to b (where b is a positive integer, e.g., b = 3), and the result k is used to determine which root index to use. For instance, k = mod(cellID, 3). If k = 0 after the modulo operation, then q1 = 1, q2 = N-1 is used; if k = 1, then q1 = 2, q2 = N-2 is used; and if k = 2, then q1 = 3, q2 = N-3 is used.

[0207] It is worth noting that in this example, q1 is chosen as a small integer, for example, q1 can be any element in Q1 = {1, 2, 3}, so that the correlation peak decreases as the frequency offset decays. And q2 = N - q1, where N is the sequence length, ensures that, for the same integer frequency offset, the time offsets of the two sequences are the same in magnitude but opposite in direction, which is beneficial for calculating frequency and time offsets.

[0208] In another possible implementation, the root index of the synchronization sequence used by the cell can also be configured by the network side. For example, cell A can choose q1 as the root index for generating its own synchronization sequence, and the network device of cell A can notify the terminal device of q1 through broadcast information or configuration information.

[0209] In other words, through the above implementation, after obtaining the root index to be used, the receiving device can locally generate a synchronization sequence for related operations. Alternatively, in another possible implementation, the receiving device can only determine the set of root indexes to be used, but not the specific root index used. In this case, the receiving device can traverse the root indexes in the root index set, that is, use the synchronization sequence generated by each root index for time-frequency synchronization. It can be understood that when the root index used by the receiving device is the same as the root index used by the serving cell, a correlation peak can be detected.

[0210] The above, combined with Figures 7 to 10 The synchronization method provided in the embodiments of this application is described in detail below. Figures 11 to 13 The apparatus provided in the embodiments of this application is described in detail. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments. Therefore, for content not described in detail, please refer to the method embodiments above. For the sake of brevity, it will not be repeated here.

[0211] Figure 11This is a schematic diagram of a communication device 1100 provided in an embodiment of this application. The communication device 1100 includes a transceiver unit 1110 and a processing unit 1120. The transceiver unit 1110 can be used to implement corresponding communication functions. The transceiver unit 1110 can also be referred to as a communication interface or a communication unit. The processing unit 1120 can be used to perform processing.

[0212] Optionally, the device 1100 may further include a storage unit, which can be used to store instructions and / or data, and the processing unit 1120 can read the instructions and / or data in the storage unit to enable the device to implement the aforementioned method embodiments.

[0213] In a first possible design, the device 1100 can be a receiving device (such as a terminal device or a network device) as described in the preceding embodiments. This device 1100 can implement the steps or processes corresponding to those executed by the receiving device in the above method embodiments. Specifically, the transceiver unit 1110 can be used to perform transceiver-related operations (such as sending and / or receiving synchronization signals) of the receiving device in the above method embodiments, and the processing unit 1120 can be used to perform processing-related operations of the receiving device in the above method embodiments, or operations other than transceiver.

[0214] In one possible implementation, the transceiver unit 1110 is configured to receive a synchronization signal generated based on a first synchronization sequence, which satisfies the following: The processing unit 1120 is used to perform frequency synchronization based on the synchronization signal; wherein, the x q (m) represents the first synchronization sequence, q represents the root index of the first synchronization sequence, and N represents the length of the first synchronization sequence. The first synchronization sequence can also be represented as... and A linear combination of these. The specific meanings of the parameters in the above expressions can be found in the descriptions in the method embodiments.

[0215] Optionally, the processing unit 1120 is specifically used to process the synchronization signal based on the first carrier signal to obtain a baseband signal, wherein the frequency of the first carrier signal is adjusted based on a first frequency value, the first frequency value belongs to a first frequency range, and the first frequency range is less than or equal to the subcarrier spacing corresponding to the subcarrier that transmits the synchronization signal; and to perform frequency synchronization based on the sampling sequence obtained by sampling the baseband signal.

[0216] For example, the first carrier signal can be understood as the local carrier signal of the receiving device.

[0217] The first frequency value can be understood as the fractional frequency offset included in the frequency deviation between the receiving device and the transmitting device, that is, a frequency offset less than or equal to one subcarrier interval.

[0218] Optionally, the processing unit 1120 is specifically used to determine a second frequency value based on the sampling sequence and the second synchronization sequence, the second synchronization sequence being generated by the receiving end and including a first sequence and a conjugate sequence of the first sequence; and to perform frequency synchronization based on the second frequency value.

[0219] For example, the first sequence is represented as the

[0220] Optionally, the processing unit 1120 is specifically configured to: sequentially extract a portion of the sampled sequence through a sliding window; perform correlation operations on each extracted portion of the sequence with a second sequence and a third sequence to obtain a first correlation value and a second correlation value, wherein the second sequence is the time-domain sequence corresponding to the first sequence and the third sequence is the time-domain sequence corresponding to the conjugate sequence of the first sequence; determine the second frequency value based on the time interval between the first time-domain position and the second time-domain position, wherein the first time-domain position is the time-domain position when the first correlation value reaches its maximum and the second time-domain position is the time-domain position when the second correlation value reaches its maximum.

[0221] Optionally, the processing unit 1120 is further configured to perform time synchronization based on the first time domain position and the second time domain position.

[0222] Optionally, the root index corresponding to the first synchronization sequence is an element in a first set, which includes one or more root indices, and any two root indices are different. The specific method for determining the root index of the synchronization sequence can be found in the description of the method embodiments.

[0223] In another possible implementation, the transceiver unit 1110 is configured to include the method comprising: receiving a first synchronization signal and a second synchronization signal, the first synchronization signal being generated based on a first synchronization sequence, the second synchronization sequence being generated based on a second synchronization sequence, the first synchronization sequence satisfying: The second synchronization sequence satisfies: Frequency synchronization is performed based on the first synchronization signal and the second synchronization signal; where x q1 (m) represents the first synchronization sequence, q1 represents the root index of the first synchronization sequence, and x q2 (m) represents the second synchronization sequence, q2 represents the root index of the second synchronization sequence, the values ​​of q1 and q2 are different, and N represents the length of the first synchronization sequence and the second synchronization sequence.

[0224] Optionally, the transceiver unit 1110 is specifically used to receive the first synchronization signal on a first time-frequency resource and to receive the second synchronization signal on a second time-frequency resource; wherein the time-domain position or frequency-domain position corresponding to the first time-frequency resource and the second time-frequency resource are different.

[0225] Optionally, the processing unit 1120 is specifically configured to: process the first synchronization signal and the second synchronization signal based on the first carrier signal to obtain a first baseband signal and a second baseband signal, wherein the frequency of the first carrier signal is adjusted based on a first frequency value, the first frequency value belongs to a first frequency range, and the first frequency range is less than or equal to the subcarrier spacing corresponding to the subcarrier that transmits the synchronization signal; and perform frequency synchronization based on a first sampling sequence and a second sampling sequence, wherein the first sampling sequence is obtained by sampling the first baseband signal, and the second sampling sequence is obtained by sampling the second baseband signal.

[0226] Optionally, the processing unit 1120 is specifically used to determine a second frequency value based on the first sampling sequence, the second sampling sequence, and the third synchronization sequence, wherein the third synchronization sequence is generated by the receiving end; and to perform frequency synchronization based on the second frequency value.

[0227] For example, the second synchronization sequence includes the first synchronization sequence and the second synchronization sequence.

[0228] Optionally, the processing unit 1120 is specifically configured to: sequentially extract a portion of the first sampling sequence at the time-domain position corresponding to the first time-frequency resource using a sliding window; perform a correlation operation between each extracted portion of the first sampling sequence and a fourth sequence to obtain a third correlation value, wherein the fourth sequence is the time-domain sequence corresponding to the first synchronization sequence; sequentially extract a portion of the second sampling sequence at the time-domain position corresponding to the second time-frequency resource using a sliding window; perform a correlation operation between each extracted portion of the second sampling sequence and a fifth sequence to obtain a fourth correlation value, wherein the fifth sequence is the time-domain sequence corresponding to the second synchronization sequence; determine the second frequency value based on the time interval between the third time-domain position and the fourth time-domain position, wherein the third time-domain position is the time-domain position where the third correlation value reaches its maximum, and the fourth time-domain position is the time-domain position where the fourth correlation value reaches its maximum.

[0229] Optionally, the processing unit 1120 is further configured to perform time synchronization based on the third time domain position and the fourth time domain position.

[0230] For example, the root index corresponding to the first synchronization sequence and the root index corresponding to the second synchronization sequence are different elements in a first set, which includes one or more root indices, and any two root indices among the plurality of root indices are different.

[0231] In a second possible design, the device 1100 can be a transmitting device (such as a network device or a terminal device) as described in the preceding embodiments. This device 1100 can implement the steps or processes corresponding to those executed by the transmitting device in the above method embodiments. Specifically, the transceiver unit 1110 can be used to perform transceiver-related operations (such as sending and / or receiving synchronization signals) of the transmitting device in the above method embodiments, and the processing unit 1120 can be used to perform processing-related operations of the transmitting device in the above method embodiments, or operations other than transceiver operations.

[0232] In one possible implementation, the processing unit 1120 is configured to generate a synchronization signal based on a first synchronization sequence, the first synchronization sequence satisfying: The transceiver unit 1110 is used to transmit the synchronization signal, which is used for frequency synchronization; wherein, x q (m) represents the first synchronization sequence, q represents the root index of the first synchronization sequence, and N represents the length of the first synchronization sequence. The first synchronization sequence is represented as... and A linear combination of .

[0233] In another possible implementation, the processing unit 1120 is used to generate a first synchronization signal based on a first synchronization sequence, the first synchronization sequence satisfying: Processing unit 1120 is further configured to generate a second synchronization signal based on a second synchronization sequence, wherein the first synchronization sequence satisfies: The transmitting unit 1110 is used to transmit the first synchronization signal and the second synchronization signal, the first synchronization signal and the second synchronization signal being used for frequency synchronization; wherein, x q1 (m) represents the first synchronization sequence, q1 represents the root index of the first synchronization sequence, and x q2 (m) represents the second synchronization sequence, q2 represents the root index of the second synchronization sequence, the values ​​of q1 and q2 are different, and N represents the length of the first synchronization sequence and the second synchronization sequence.

[0234] Optionally, the transceiver unit 1110 is specifically used to transmit the first synchronization signal on a first time-frequency resource and transmit the second synchronization signal on a second time-frequency resource; wherein the time domain position or frequency domain position corresponding to the first time-frequency resource and the second time-frequency resource are different.

[0235] For example, the root index corresponding to the first synchronization sequence is an element in a first set, which includes one or more root indices, and any two root indices among the plurality of root indices are different.

[0236] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0237] It should also be understood that the device 1100 here is embodied in the form of a functional unit. The term "unit" here can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor, etc.) and memory for executing one or more software or firmware programs, integrated logic circuitry, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the device 1100 can be specifically the communication device in the above embodiments, and can be used to execute the various processes and / or steps corresponding to the communication device in the above method embodiments; to avoid repetition, these will not be described again here.

[0238] The apparatus 1100 of each of the above-described schemes has the function of implementing the corresponding steps performed by the communication device (such as a terminal device or a network device) in the above-described methods. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (e.g., the transmitting unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as processing units, can be replaced by processors, respectively executing the transceiver operations and related processing operations in each method embodiment.

[0239] In addition, the transceiver unit 1110 described above can also be a transceiver circuit (for example, it may include a receiving circuit and a transmitting circuit), and the processing unit can be a processing circuit.

[0240] It should be pointed out that, Figure 11 The device mentioned can be the communication device (such as a terminal device or a network device) in the foregoing embodiments, or it can be a chip or a chip system, such as a system on chip (SoC). The transceiver unit can be an input / output circuit or a communication interface; the processing unit is a processor, microprocessor, or integrated circuit integrated on the chip, which is not limited here.

[0241] Figure 12 This is a schematic diagram of another communication device 1200 provided in an embodiment of this application. The device 1200 includes a processor 1210, which is coupled to a memory 1220. The memory 1220 is used to store computer programs or instructions and / or data. The processor 1210 is used to execute the computer programs or instructions stored in the memory 1220, or to read the data stored in the memory 1220, in order to execute the methods in the above method embodiments.

[0242] Optionally, there may be one or more processors 1210.

[0243] Optionally, the memory 1220 may be one or more.

[0244] Alternatively, the memory 1220 can be integrated with the processor 1210, or it can be set separately.

[0245] Optionally, such as Figure 12 As shown, the device 1200 also includes a transceiver 1230 for receiving and / or transmitting signals. For example, a processor 1210 is used to control the transceiver 1230 to receive and / or transmit signals.

[0246] As an example, processor 1210 may have Figure 11 The processing unit 1120 shown has the function of a storage unit, the memory 1220 can have the function of a storage unit, and the transceiver 1230 can have... Figure 11 The function of the transceiver unit 1110 shown is illustrated.

[0247] As one option, the device 1200 is used to implement the operations performed by a communication device (such as a terminal device or a network device) in the various method embodiments described above.

[0248] For example, processor 1210 is used to execute computer programs or instructions stored in memory 1220 to implement the relevant operations of the communication device in the various method embodiments described above.

[0249] It should be understood that the processor mentioned in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0250] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory and / or non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0251] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) can be integrated into the processor.

[0252] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0253] Figure 13 This is a schematic diagram of a chip system 1300 provided in an embodiment of this application. The chip system 1300 (or may also be referred to as a processing system) includes logic circuitry 1310 and an input / output interface 1320.

[0254] The logic circuit 1310 can be a processing circuit in the chip system 1300. The logic circuit 1310 can be coupled to a memory unit, calling instructions from the memory unit, enabling the chip system 1300 to implement the methods and functions of the embodiments of this application. The input / output interface 1320 can be an input / output circuit in the chip system 1300, outputting processed information from the chip system 1300, or inputting data or signaling information to be processed into the chip system 1300 for processing.

[0255] As one approach, the chip system 1300 is used to implement the operations performed by the receiving device (such as a terminal device or a network device) in the various method embodiments described above.

[0256] For example, logic circuit 1310 is used to implement processing-related operations performed by the receiving device in the above method embodiments; input / output interface 1320 is used to implement sending and / or receiving-related operations performed by the receiving device in the above method embodiments.

[0257] As an alternative, the chip system 1300 is used to implement the operations performed by the transmitting device (such as a network device or a terminal device) in the various method embodiments described above.

[0258] For example, logic circuit 1310 is used to implement processing-related operations performed by the transmitting device in the above method embodiments; input / output interface 1320 is used to implement sending and / or receiving-related operations performed by the transmitting device in the above method embodiments.

[0259] This application also provides a computer-readable storage medium storing a computer program or instructions for implementing the methods executed by a communication device (such as a terminal device or a network device) in the above-described method embodiments. For example, when the computer program or instructions are run on the communication device, they cause the communication device (such as a terminal device or a network device) to execute the above-described methods (such as method 700 or method 900).

[0260] This application also provides a computer program product comprising instructions that, when executed by a computer, implement the methods described above as performed by a communication device (such as a terminal device or a network device). For example, when the computer program or instructions are run on the communication device, the communication device (such as a terminal device or a network device) performs the methods described above (such as method 700 or method 900).

[0261] This application also provides a communication system, which includes the receiving end device and / or transmitting end device described in the above embodiments. For example, the system includes... Figure 7 The receiving end device and / or transmitting end device in the embodiments. For example, the system includes... Figure 9 The receiving end device and / or transmitting end device in the embodiments.

[0262] The explanations and beneficial effects of the relevant contents in any of the devices provided above can be found in the corresponding method embodiments provided above, and will not be repeated here.

[0263] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of apparatus or units may be electrical, mechanical, or other forms.

[0264] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks, SSDs). For example, the aforementioned available media include, but are not limited to, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks, and other media capable of storing program code.

[0265] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A synchronization method, characterized in that, Applied to a receiving device, the method includes: A synchronization signal is received, the synchronization signal being generated based on a first synchronization sequence, the first synchronization sequence satisfying: Frequency synchronization is performed based on the aforementioned synchronization signal; Wherein, the x q (m) represents the first synchronization sequence, q represents the root index of the first synchronization sequence, N represents the length of the first synchronization sequence, and α is a real or complex number. The first synchronization sequence can also be represented as... and A linear combination of .

2. The method according to claim 1, characterized in that, The frequency synchronization based on the synchronization signal includes: The synchronization signal is processed based on the first carrier signal to obtain the baseband signal. The frequency of the first carrier signal is adjusted based on a first frequency value. The first frequency value belongs to a first frequency range. The first frequency range is less than or equal to the subcarrier interval corresponding to the subcarrier that transmits the synchronization signal. Frequency synchronization is performed based on the sampling sequence obtained by sampling the baseband signal.

3. The method according to claim 2, characterized in that, The frequency synchronization based on the sampled sequence obtained by processing the baseband signal includes: A second frequency value is determined based on the sampling sequence and the second synchronization sequence, wherein the second synchronization sequence is generated by the receiving end and includes a first sequence and a conjugate sequence of the first sequence; Frequency synchronization is performed based on the second frequency value.

4. The method according to claim 3, characterized in that, The first sequence is represented as the 5. The method according to claim 3 or 4, characterized in that, Determining the second frequency value based on the sampling sequence and the second synchronization sequence includes: A portion of the sampled sequence is sequentially extracted using a sliding window; Each extracted portion of the sequence is correlated with the second sequence and the third sequence to obtain a first correlation value and a second correlation value. The second sequence is the time-domain sequence corresponding to the first sequence, and the third sequence is the time-domain sequence corresponding to the conjugate sequence of the first sequence. The second frequency value is determined based on the time interval between the first time domain position and the second time domain position, wherein the first time domain position is the time domain position when the first correlation value reaches its maximum, and the second time domain position is the time domain position when the second correlation value reaches its maximum.

6. The method according to claim 5, characterized in that, The method further includes: Time synchronization is performed based on the first time domain position and the second time domain position.

7. The method according to any one of claims 1 to 6, characterized in that, The root index corresponding to the first synchronization sequence is an element in the first set, which includes one or more root indices, and any two root indices among the plurality of root indices are different.

8. A synchronization method, characterized in that, Applied to a receiving device, the method includes: Receive a first synchronization signal and a second synchronization signal, wherein the first synchronization signal is generated based on a first synchronization sequence, and the second synchronization sequence is generated based on a second synchronization sequence, and the first synchronization sequence satisfies: The second synchronization sequence satisfies: Frequency synchronization is performed based on the first synchronization signal and the second synchronization signal; Where, x q1 (m) represents the first synchronization sequence, q1 represents the root index of the first synchronization sequence, and x q2 (m) represents the second synchronization sequence, q2 represents the root index of the second synchronization sequence, the values ​​of q1 and q2 are different, and N represents the length of the first synchronization sequence and the second synchronization sequence.

9. The method according to claim 8, characterized in that, Receiving the first synchronization signal and the second synchronization signal includes: The first synchronization signal is received in the first time-frequency resource; The second synchronization signal is received in the second time-frequency resource; The time-domain or frequency-domain positions of the first time-frequency resource and the second time-frequency resource are different.

10. The method according to claim 9, characterized in that, The frequency synchronization based on the first synchronization signal and the second synchronization signal includes: The first synchronization signal and the second synchronization signal are processed based on the first carrier signal to obtain the first baseband signal and the second baseband signal respectively. The frequency of the first carrier signal is adjusted based on the first frequency value. The first frequency value belongs to the first frequency range. The first frequency range is less than or equal to the subcarrier interval corresponding to the subcarrier that transmits the synchronization signal. Frequency synchronization is performed based on a first sampling sequence and a second sampling sequence, wherein the first sampling sequence is obtained by sampling the first baseband signal and the second sampling sequence is obtained by sampling the second baseband signal.

11. The method according to claim 10, characterized in that, The frequency synchronization based on the first sampling sequence and the second sampling sequence includes: A second frequency value is determined based on the first sampling sequence, the second sampling sequence, and the third synchronization sequence, wherein the third synchronization sequence is generated by the receiving end. Frequency synchronization is performed based on the second frequency value.

12. The method according to claim 11, characterized in that, The second synchronization sequence includes the first synchronization sequence and the second synchronization sequence.

13. The method according to claim 11 or 12, characterized in that, The step of determining the second frequency value based on the first sampling sequence, the second sampling sequence, and the third synchronization sequence includes: At the time domain location corresponding to the first time-frequency resource, a portion of the first sampling sequence is sequentially extracted using a sliding window; A third correlation value is obtained by performing a correlation operation between a portion of the first sampled sequence and the fourth sequence, wherein the fourth sequence is the time-domain sequence corresponding to the first synchronization sequence. At the time domain location corresponding to the second time-frequency resource, a portion of the second sampling sequence is sequentially extracted using a sliding window; A fourth correlation value is obtained by performing a correlation operation between a portion of the second sampling sequence extracted each time and the fifth sequence, wherein the fifth sequence is the time-domain sequence corresponding to the second synchronization sequence; The second frequency value is determined based on the time interval between the third time domain position and the fourth time domain position, wherein the third time domain position is the time domain position when the third correlation value reaches its maximum, and the fourth time domain position is the time domain position when the fourth correlation value reaches its maximum.

14. The method according to claim 13, characterized in that, The method further includes: Time synchronization is performed based on the third time domain position and the fourth time domain position.

15. The method according to any one of claims 8 to 14, characterized in that, The root index corresponding to the first synchronization sequence and the root index corresponding to the second synchronization sequence are different elements in the first set. The first set includes one or more root indices, and any two root indices among the multiple root indices are different.

16. A synchronization method, characterized in that, Applied to a transmitting device, the method includes: A synchronization signal is generated based on a first synchronization sequence, wherein the first synchronization sequence satisfies: Send the synchronization signal, which is used for frequency synchronization; Where, x q (m) represents the first synchronization sequence, q represents the root index of the first synchronization sequence, N represents the length of the first synchronization sequence, and α is a real or complex number. The first synchronization sequence is represented as... and A linear combination of .

17. A synchronization method, characterized in that, Applied to a transmitting device, the method includes: A first synchronization signal is generated based on a first synchronization sequence, wherein the first synchronization sequence satisfies: A second synchronization signal is generated based on a second synchronization sequence, wherein the first synchronization sequence satisfies: Send the first synchronization signal and the second synchronization signal, which are used for frequency synchronization; Where, x q1 (m) represents the first synchronization sequence, q1 represents the root index of the first synchronization sequence, and x q2 (m) represents the second synchronization sequence, q2 represents the root index of the second synchronization sequence, the values ​​of q1 and q2 are different, and N represents the length of the first synchronization sequence and the second synchronization sequence.

18. The method according to claim 17, characterized in that, The transmission of the first synchronization signal and the second synchronization signal includes: The first synchronization signal is transmitted on the first time-frequency resource; The second synchronization signal is transmitted on the second time-frequency resource; The time-domain or frequency-domain positions of the first time-frequency resource and the second time-frequency resource are different.

19. The method according to any one of claims 16 to 18, characterized in that, The root index corresponding to the first synchronization sequence is an element in the first set, which includes one or more root indices, and any two root indices among the plurality of root indices are different.

20. A communication device, characterized in that, Includes modules or units for performing the method according to any one of claims 1 to 19.

21. A communication device, characterized in that, Includes a processor configured to cause the communication device to perform the method of any one of claims 1 to 19.

22. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions that, when executed on a communication device, cause the communication device to perform the method as described in any one of claims 1 to 19.

23. A chip or chip system, characterized in that, At least one processor is configured to retrieve and run a computer program from memory, causing a communication device equipped with the chip system to perform the method of any one of claims 1 to 19.

24. A computer program product, characterized in that, The computer program product includes a computer program or instructions that, when executed on a communication device, cause the communication device to perform the method as described in any one of claims 1 to 19.

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