Communication method and apparatus

Abstract

Provided in the embodiments of the present application are a communication method and apparatus. The method comprises: a terminal device determining the current global synchronization channel number (GSCN) to be a first GSCN; then, the terminal device receiving first information from a network device, wherein the first information is used for indicating information associated with a second GSCN, and the second GSCN is a GSCN used by the network device to send an SSB; and on the basis of the first GSCN and the first information, the terminal device determining a third GSCN. In the method, a network device can provide a terminal device with information associated with a second GSCN on a network device side; in this way, the terminal device can combine the associated information with a first GSCN determined by the terminal device itself, so as to determine a third GSCN closer to the second GSCN; and subsequently, the terminal device performs downlink synchronization with the network device on the basis of the third GSCN, such that the accuracy of downlink synchronization can be effectively improved, thereby ensuring the subsequent communication performance.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on April 3, 2024, with application number 202410404903.X and application name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of wireless communication technology, and in particular to a communication method and device. Background Art

[0004] Compared to terrestrial communication systems, a major characteristic of non-terrestrial communication systems is that the spectrum of the same signal on the transmitting and receiving sides may deviate, known as frequency deviation. This deviation primarily involves Doppler shift, which is the phase and frequency change caused by propagation distance differences when a mobile device moves at a constant speed in a certain direction. The Doppler shift of satellite systems is typically much greater than that of terrestrial systems. Furthermore, crystal oscillator errors on the transmitting and receiving sides are also a significant factor causing frequency deviation. Frequency deviation can cause frequency misalignment between the transmitting and receiving sides, severely impacting communication performance.

[0005] Typically, network equipment can send synchronization signal blocks (SSBs) to terminal devices through broadcast beams in several different directions for synchronization during the initial access phase of the terminal devices. On the terminal side, SSB search / detection is performed after power-on for downlink time and frequency synchronization.

[0006] The existing technology defines a channel raster to indicate the channel frequency domain position, which can be used to place data, reference signals (RS), control channels, etc. Since the bandwidth of the new radio (NR) cell is very wide, the terminal device performs blind detection according to the channel raster, which will make the terminal device access the cell very slow. Therefore, in order to enable the terminal device to quickly search for the cell (detect SSB), NR further defines the center frequency and interval of SSB, which is called the synchronization raster, and uses the global synchronization channel number (GSCN) to limit the frequency range of the terminal device to search for SSB. In this way, the terminal device can scan the frequency according to the synchronization raster to determine the corresponding GSCN for downlink synchronization with the network device.

[0007] In non-terrestrial communication systems, the high speed of satellites and the long transmission distances can lead to frequency offsets between terminal devices and satellites due to various factors. Consequently, when a terminal device receives an SSB signal from a satellite, the detected SSB frequency position deviates from the actual SSB frequency position. This results in an inaccurate GSCN determined by the terminal device based on the detected SSB frequency. Consequently, when the terminal device performs downlink synchronization based on the detected GSCN, there is a frequency offset, which affects subsequent communication performance. Summary of the Invention

[0008] The present application proposes a communication method and device, which can effectively improve the accuracy of the terminal device in determining the global synchronization channel number GSCN. The subsequent terminal device performs downlink synchronization with the network device based on the determined GSCN, which can effectively improve the accuracy of downlink synchronization and thus ensure subsequent communication performance.

[0009] In a first aspect, the present application provides a communication method, which can be executed by a terminal device, or by a module (such as a processor, chip, or chip system, etc.) applied to the terminal device, or by a logical node, logical module, or software that can implement all or part of the terminal device functions. The method includes: the terminal device determines that the current global synchronization channel number GSCN is a first GSCN; the terminal device receives first information from a network device, the first information is used to indicate information associated with a second GSCN, and the second GSCN is the GSCN for sending a synchronization signal block SSB by the network device; and then the terminal device determines a third GSCN based on the first GSCN and the first information.

[0010] In the above description, the second GSCN can be understood as the actual GSCN used by the network device to send the SSB, hereinafter referred to as the actual GSCN or true GSCN. The third GSCN can refer to the GSCN determined by the terminal device based on the first GSCN detected by itself and the first information. The terminal device subsequently performs downlink synchronization and communication with the network device based on the third GSCN.

[0011] In an embodiment of the present application, the network device can be an access network device in a terrestrial communication system (such as a base station), or it can be an access network device in a non-terrestrial communication system, such as a satellite. The satellite can have some or all of the functions of a terrestrial access network device (such as a base station), and there is no limitation on this.

[0012] In the present application scheme, the terminal device can obtain information associated with the second GSCN of the network device from the network device, so that the terminal device can combine the associated information with the first GSCN detected by itself to determine the third GSCN, which can effectively improve the accuracy of the third GSCN. The subsequent terminal device can perform downlink frequency synchronization with the network device based on the third GSCN with higher accuracy, thereby ensuring subsequent communication performance.

[0013] In the embodiment of the present application, the first information is used to indicate information associated with the second GSCN, and may include but is not limited to the following specific implementations:

[0014] Implementation method 1: There is a correspondence between the GSCN and the physical cell identifier PCI; the first information is used to determine the first PCI.

[0015] The terminal device determines the third GSCN based on the first GSCN and the first information, which may include: if the first GSCN and the first PCI satisfy the correspondence, the value of the third GSCN is equal to the value of the first GSCN; if the first GSCN and the first PCI do not satisfy the correspondence, determining a target GSCN that satisfies the correspondence with the first PCI from at least one candidate GSCN, and the distance between the center frequency position of the SSB corresponding to the target GSCN and the center frequency position of the SSB detected by the terminal device for the network device is the smallest, and the value of the third GSCN is equal to the value of the target GSCN; wherein the at least one candidate GSCN is determined by the working frequency band corresponding to the terminal device.

[0016] In an embodiment of the present application, the correspondence between GSCN and PCI may refer to the existence of one or more association relationships between GSCN and PCI, that is, if one of the information is known, the other information can be derived based on the association relationship between the two. For example, if PCI is known, part or all of the corresponding GSCN information can be derived based on the association relationship between GSCN and PCI. In addition, the correspondence between GSCN and PCI can be pre-set or established, and both the network device side and the terminal device side can know the correspondence. The correspondence between GSCN and PCI can also be pre-negotiated or agreed upon between the network device side and the terminal device side, and this application does not limit this.

[0017] For example, the correspondence between GSCN and PCI may include but is not limited to the following:

[0018] 1. There is an odd-even correspondence between GSCN and PCI. That is, the parity of GSCN and PCI is opposite or opposite. For example, when PCI is odd, the corresponding GSCN is even; and vice versa, when PCI is even, the corresponding GSCN is odd.

[0019] The existence of an even-odd correspondence between GSCN and PCI is applicable to, but not limited to, scenarios where the frequency offset between the network device and the terminal device does not exceed one GSCN interval.

[0020] 2. There is an odd-odd correspondence between GSCN and PCI, or an even-even correspondence, that is, the parity of the GSCN and PCI is the same. For example, when the PCI is odd, the corresponding GSCN is odd; and when the PCI is even, the corresponding GSCN is even.

[0021] In addition, there may be other characteristic correspondences or other forms of correspondences between GSCN and PCI, which are not listed one by one in this application. For example, the correspondence between GSCN and PCI can be a preset formula, numerical value, symbol, table, etc. For example, the difference between GSCN and PCI is uniformly preset, or the GSCN and PCI satisfy a preset function, or the correspondence between GSCN and PCI can be specified by a preset table, etc.

[0022] In one possible implementation, the first information is a primary synchronization signal PSS sequence and a secondary synchronization signal SSS sequence in an SSB, and the primary synchronization signal PSS sequence and the secondary synchronization signal SSS sequence can be used to determine a first PCI.

[0023] In an embodiment of the present application, after the terminal device determines that the current GSCN is the first GSCN, it searches or detects SSB in the time domain of the corresponding frequency point. After receiving the PSS and SSS, the terminal device can determine the first PCI through the PSS and SSS.

[0024] Through this implementation, the terminal device can effectively obtain the first PCI indicated by the network device.

[0025] Implementation method 2: The first information is used to indicate part or all of the information of the second GSCN.

[0026] In implementation mode 2, part of the information of the second GSCN may be, but is not limited to, any of the following:

[0027] (1) At least one digit of the second GSCN.

[0028] The terminal device determines the third GSCN based on the first GSCN and the first information, which may include: if the value of at least one digit in the same position in the first GSCN is consistent with the value of at least one digit in the second GSCN, the value of the third GSCN is equal to the value of the first GSCN; if the value of at least one digit in the same position in the first GSCN is inconsistent with the value of at least one digit in the second GSCN, the value of the first GSCN is adjusted according to at least one digit of the second GSCN to obtain an adjusted first GSCN, and the value of the third GSCN is equal to the value of the adjusted first GSCN.

[0029] (2) The value of the first parameter M corresponding to the second GSCN.

[0030] The terminal device determining the third GSCN based on the first GSCN and the first information may include: the terminal device first determining a value of a first parameter M and a value of a second parameter N corresponding to the first GSCN; the first parameter M and the second parameter N are used to represent the center frequency position of the SSB corresponding to the GSCN and the GSCN;

[0031] If the value of the first parameter M corresponding to the first GSCN is equal to the value of the first parameter M corresponding to the second GSCN, the value of the third GSCN is equal to the value of the first GSCN;

[0032] If the value of the first parameter M corresponding to the first GSCN is not equal to the value of the first parameter M corresponding to the second GSCN, the terminal device updates the value of the first parameter M corresponding to the first GSCN to the value of the first parameter M corresponding to the second GSCN, and obtains the updated value of the first parameter M corresponding to the first GSCN; then determines the updated value of the first GSCN based on the updated value of the first parameter M corresponding to the first GSCN and the value of the second parameter N corresponding to the first GSCN, and the value of the third GSCN is equal to the updated value of the first GSCN.

[0033] In an embodiment of the present application, all information of the second GSCN may be, but is not limited to: all digits of the second GSCN (ie, the second GSCN value), or the binary number of the second GSCN, or the M and N values ​​corresponding to the second GSCN.

[0034] In one possible implementation, the first information is carried in a master system information block (MIB) of the SSB. For example, 2 bits of information are added to the MIB information, and the added 2 bits of information are used to indicate the value of the first parameter M corresponding to the second GSCN.

[0035] In an embodiment of the present application, after determining that the current GSCN is the first GSCN, the terminal device searches for or detects SSB in the time domain of the corresponding frequency point. After receiving the PBCH, the terminal device obtains the value of the first parameter M corresponding to the second GSCN by parsing the MIB therein.

[0036] Through this implementation, the terminal device can effectively obtain the value of the first parameter M corresponding to the second GSCN from the network device.

[0037] Through the above implementation methods, the terminal device can obtain information associated with the second GSCN (i.e., the actual GSCN) through the first information of the network device. Then, based on the information associated with the second GSCN, the terminal device can not only effectively determine the correctness of the first GSCN determined / detected by itself, but also effectively obtain the third GSCN for subsequent downlink synchronization and communication between the terminal device and the network device.

[0038] In a second aspect, the present application provides a communication method, which can be executed by a network device, or by a module (such as a processor, chip, or chip system) applied to the network device, or by a logical node, logical module, or software that can implement all or part of the network device functions. The method includes: the network device generates first information, the first information is used to indicate information associated with a second global synchronization channel number GSCN, the second GSCN is the GSCN for the network device to send SSB; the network device sends the first information.

[0039] In one possible implementation, the network device sending the first information may include: the network device sending an SSB to the terminal device based on the second GSCN, where the SSB includes the first information. The terminal device may be a specific terminal device or a general terminal device, and this is not limited. The second GSCN may be understood as the actual GSCN used by the network device to send the SSB, hereinafter referred to as the actual GSCN or the real GSCN.

[0040] In an embodiment of the present application, the network device can be an access network device in a terrestrial communication system (such as a base station), or it can be an access network device in a non-terrestrial communication system, such as a satellite. The satellite can have some or all of the functions of a terrestrial access network device (such as a base station), and there is no limitation on this.

[0041] In the present application scheme, the network device can provide the terminal device with information associated with the second GSCN of the network device. The terminal device can combine the associated information and the first GSCN detected by itself to determine the third GSCN. This can effectively improve the accuracy of the third GSCN. The subsequent terminal device can perform downlink frequency synchronization with the network device based on the third GSCN with higher accuracy, thereby ensuring subsequent communication performance.

[0042] In the embodiment of the present application, the first information is used to indicate information associated with the second GSCN, and may include but is not limited to the following specific implementations:

[0043] Implementation method 1: There is a correspondence between the GSCN and the physical cell identifier PCI, and the first information is used to determine the first physical cell identifier PCI.

[0044] Implementation method 2: The first information is used to indicate part or all of the information of the second GSCN.

[0045] Through the above-mentioned implementation methods, the network device can indicate the information associated with the second GSCN (i.e., the actual GSCN) to the terminal device, which can not only assist the terminal device to effectively determine the correctness of the first GSCN determined / detected by itself, but also assist the terminal device to effectively obtain the third GSCN for subsequent downlink synchronization and communication between the terminal device and the network device.

[0046] In one possible implementation, the partial information of the second GSCN may be, but is not limited to, any of the following:

[0047] (1) At least one digit of the second GSCN;

[0048] (2) The value of the first parameter M corresponding to the second GSCN.

[0049] In one possible implementation, the first information is a primary synchronization signal PSS sequence and a secondary synchronization signal SSS sequence in an SSB, and the primary synchronization signal PSS sequence and the secondary synchronization signal SSS sequence are used to determine a first PCI.

[0050] In an embodiment of the present application, all information of the second GSCN may be, but is not limited to: all digits of the second GSCN (ie, the second GSCN value), or the binary number of the second GSCN, or the M and N values ​​corresponding to the second GSCN.

[0051] In one possible implementation, the first information is carried in a master system information block (MIB) of an SSB of the network device. This implementation enables the terminal device to effectively obtain the value of the first parameter M corresponding to the second GSCN indicated by the first information from the network device.

[0052] An embodiment of the present application also provides another communication method, which can refer to the contents described in the third and fourth aspects below.

[0053] On the third aspect, the present application provides a communication method, which can be executed by a terminal device, or by a module (such as a processor, chip, or chip system, etc.) applied to the terminal device, or by a logical node, logical module or software that can realize all or part of the terminal device functions. The method includes: the terminal device determines a first GSCN area; the range of the first GSCN area is the same as the range of the second GSCN area, the second GSCN area is determined by the working frequency band corresponding to the terminal device, the first GSCN area and the second GSCN area respectively include at least two GSCNs, and the interval between the two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between the two adjacent GSCNs to be detected in the second GSCN area; the terminal device receives an SSB from a network device based on the first GSCN area, and determines the first GSCN corresponding to the received SSB as the current global synchronization channel number GSCN.

[0054] In an embodiment of the present application, the network device can be an access network device in a terrestrial communication system (such as a base station), or it can be an access network device in a non-terrestrial communication system, such as a satellite. The satellite can have some or all of the functions of a terrestrial access network device (such as a base station), and there is no limitation on this.

[0055] In the present application scheme, compared with the interval between two adjacent GSCNs to be detected in the second GSCN area (i.e., the GSCN area / range corresponding to the working frequency band of the terminal device), the interval between two adjacent GSCNs to be detected in the first GSCN area is larger. This can effectively reduce the probability of the terminal device misdetecting the GSCN when detecting the SSB of the network device based on the first GSCN area and determining / detecting the current GSCN, thereby improving the accuracy of downlink frequency synchronization and ensuring subsequent communication performance. In addition, it can also improve the efficiency of the terminal device accessing the network and reduce the access delay of the terminal device.

[0056] In this embodiment of the present application, the center frequency position of the SSB corresponding to the GSCN in the second GSCN area is represented by the following information:

[0057] The first parameter M, the first step value of the first parameter M, the second parameter N, the step value of the second parameter N;

[0058] The interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the second GSCN area is associated with the first step value and / or the step value of the second parameter N, and N and M are positive integers.

[0059] In the above, the second GSCN area can be regarded as a GSCN range defined in the prior art, and the GSCN range can be associated with the operating frequency band corresponding to the terminal device. In addition, the center frequency position of the SSB corresponding to each GSCN in the second GSCN area can be determined in the same manner as in the prior art.

[0060] In one possible implementation, the center frequency position of the SSB corresponding to the GSCN in the first GSCN area is represented by the following information:

[0061] The first parameter M, the second step value of the first parameter M, the second parameter N, the step value of the second parameter N;

[0062] Among them, the interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the first GSCN area is associated with the second step value and / or the step value of the second parameter N, the second step value is greater than the first step value of the first parameter M, and N and M are positive integers.

[0063] Through this implementation, the frequency interval between two adjacent GSCNs to be detected in the first GSCN area (or called the first GSCN range) can be effectively increased / expanded, thereby effectively reducing the probability of subsequent terminal devices misdetecting GSCN due to the existing frequency deviation, and improving the accuracy of terminal devices in detecting GSCN.

[0064] In one possible implementation, the interval between the center frequency position of the SSB corresponding to the GSCN in the first GSCN area and the full-bandwidth downlink center frequency position of the transmission channel (such as the physical downlink shared channel PDSCH or the physical downlink control channel PDCCH) is an integer multiple of 15kHz.

[0065] In another possible implementation, the second GSCN area corresponds to the first step distance, which is used to represent the absolute difference between two adjacent GSCNs to be detected in the second GSCN area. The first GSCN area corresponds to the second step distance, which is used to represent the absolute difference between two adjacent GSCNs to be detected in the first GSCN area, and the value of the second step distance is greater than the value of the first step distance corresponding to the second GSCN area.

[0066] In the above description, the second GSCN area can be regarded as a GSCN range defined in the prior art, and the GSCN range can be associated with the operating frequency band corresponding to the terminal device. In addition, the first step distance corresponding to the second GSCN area can be the same as that in the prior art.

[0067] In this embodiment, the terminal device performs detection according to the second step corresponding to the first GSCN area. The interval between each two adjacent GSCNs that the terminal device needs to detect is larger, so the probability of the terminal device misdetecting GSCN due to frequency offset is lower.

[0068] In a fourth aspect, the present application provides a communication method, which can be executed by a network device, or by a module (such as a processor, chip, or chip system, etc.) applied to the network device, or by a logical node, logic module or software that can realize all or part of the network device function. The method includes: the network device determines the second GSCN from the first GSCN area; the range of the first GSCN area is the same as the range of the second GSCN area, the second GSCN area is determined according to the working frequency band corresponding to the terminal device, the first GSCN area and the second GSCN area respectively include at least two GSCNs, and the frequency interval corresponding to the two adjacent GSCNs in the first GSCN area is greater than the frequency interval corresponding to the two adjacent GSCNs in the second GSCN area; the network device sends SSB based on the second GSCN.

[0069] In an embodiment of the present application, the network device can be an access network device in a terrestrial communication system (such as a base station), or it can be an access network device in a non-terrestrial communication system, such as a satellite. The satellite can have some or all of the functions of a terrestrial access network device (such as a base station), and there is no limitation on this.

[0070] In the present application scheme, compared with the second GSCN area (i.e., the GSCN area / range corresponding to the working frequency band of the terminal device), based on the first GSCN area, the frequency interval between the two adjacent GSCNs that the terminal device needs to detect is larger, so that when there is a frequency offset between the terminal device and the network device, the probability of the terminal device misdetecting the GSCN can be reduced, thereby improving the accuracy of the downlink frequency synchronization between the terminal device and the network device, thereby ensuring subsequent communication performance. In order to ensure that the solutions applied on the network device side and the terminal device side are consistent, the network device side can also use the first GSCN area.

[0071] In one possible implementation, the center frequency position of the SSB corresponding to the GSCN in the second GSCN area is represented by the following information: a first parameter M, a first step value of the first parameter M, a second parameter N, and a step value of the second parameter N; wherein, the interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the second GSCN area is associated with the first step value and / or the step value of the second parameter N, and N and M are positive integers.

[0072] In one possible implementation, the center frequency position of the SSB corresponding to the GSCN in the first GSCN area is represented by the following information: a first parameter M, a second step value of the first parameter M, a second parameter N, and a step value of the second parameter N;

[0073] Among them, the interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the first GSCN area is associated with the second step value and / or the step value of the second parameter N, the second step value is greater than the first step value of the first parameter M, and N and M are positive integers.

[0074] Through this implementation, the frequency interval between two adjacent GSCNs in the first GSCN area (or referred to as the first GSCN range) can be effectively increased / expanded. From the perspective of a terminal device, when the terminal device searches for the SSB of a network device based on the first GSCN area, the frequency interval between two adjacent GSCNs that need to be detected is increased. Therefore, the probability of the terminal device misdetecting a GSCN due to the existing frequency offset can be reduced, thereby effectively improving the accuracy of the terminal device in determining or detecting the GSCN.

[0075] In an embodiment of the present application, the interval between the center frequency position of the SSB corresponding to the GSCN in the first GSCN area and the full-bandwidth downlink center frequency position of the transmission channel (such as PDSCH or PDCCH) is an integer multiple of 15kHz.

[0076] In a fifth aspect, the present application further provides a communication device, which is a terminal device or a chip corresponding to the terminal device. The communication device has the function of implementing any of the methods provided in the first or third aspects above. The communication device can be implemented in hardware or by hardware executing corresponding software implementations. The hardware or software includes one or more units or modules corresponding to the above functions.

[0077] In one possible design, the communication device includes a processor configured to support the communication device in executing the corresponding functions of the terminal device in the method described above. The communication device may also include a memory, which may be coupled to the processor and stores program instructions and data necessary for the communication device. Optionally, the communication device also includes an interface circuit for supporting communication between the communication device and other communication devices, such as the transmission and reception of data or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0078] In one possible design, the communication device includes corresponding functional modules for implementing the steps in the above method. The functions can be implemented by hardware or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions.

[0079] In one possible design, the structure of the communication device includes a processing unit and a communication unit, which can perform the corresponding functions in the above method examples. For details, please refer to the description of the method provided in the first aspect or the third aspect, which will not be repeated here.

[0080] In a sixth aspect, the present application further provides a communication device, which is a network device or a chip corresponding to the network device. The communication device has the function of implementing any of the methods provided in the second or fourth aspects above. The communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0081] In one possible design, the communication device includes a processor configured to support the communication device in executing the corresponding functions of the network device in the method described above. The communication device may also include a memory, which may be coupled to the processor and stores program instructions and data necessary for the communication device. Optionally, the communication device also includes an interface circuit for supporting communication between the communication device and other communication devices, such as the transmission and reception of data or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0082] In one possible design, the communication device includes corresponding functional modules for implementing the steps in the above method. The functions can be implemented by hardware or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions.

[0083] In one possible design, the structure of the communication device includes a processing unit and a communication unit, which can perform the corresponding functions in the above method examples. For details, please refer to the description of the method provided in the second aspect or the fourth aspect, which will not be repeated here.

[0084] In the seventh aspect, a communication device is provided, comprising a processor and an interface circuit, the interface circuit being used to receive signals from other communication devices outside the communication device and transmit them to the processor or to send signals from the processor to other communication devices outside the communication device, the processor being used to implement the method of the aforementioned first aspect and any possible implementation thereof through a logic circuit or executing code instructions, or the processor being used to implement the method of the aforementioned third aspect and any possible implementation thereof through a logic circuit or executing code instructions.

[0085] In an eighth aspect, a communication device is provided, comprising a processor and an interface circuit, the interface circuit being used to receive signals from other communication devices outside the communication device and transmit them to the processor or to send signals from the processor to other communication devices outside the communication device, the processor being used to implement the method of the aforementioned second aspect and any possible implementation thereof through a logic circuit or executing code instructions, or the processor being used to implement the method of the aforementioned fourth aspect and any possible implementation thereof through a logic circuit or executing code instructions.

[0086] In the ninth aspect, a computer-readable storage medium is provided, which stores a computer program or instruction. When the computer program or instruction is executed by a processor, the method of any one of the first to fourth aspects and any possible implementation methods thereof is implemented.

[0087] In a tenth aspect, a computer program product storing instructions is provided, which, when executed by a processor, implements the methods in the aforementioned first to fourth aspects and any possible implementations thereof.

[0088] In an eleventh aspect, a chip system is provided, comprising a processor and a memory, for implementing the method of the first through fourth aspects and any possible implementation thereof. The chip system may be composed of a chip alone or may include a chip and other discrete components.

[0089] In a twelfth aspect, a communication system is provided, which includes the terminal device described in the first aspect and the network device described in the second aspect.

[0090] In the thirteenth aspect, a communication system is provided, which includes the terminal device described in the third aspect and the network device described in the fourth aspect.

[0091] It should be noted that the technical effects that can be achieved by any possible implementation method of the above-mentioned fifth to thirteenth aspects or the fifth to thirteenth aspects can be correspondingly described with reference to the technical effects that can be achieved by any possible implementation method of the above-mentioned first to fourth aspects or the first to fourth aspects, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] FIG1A is a schematic diagram of a communication system to which the method according to an embodiment of the present application is applicable;

[0093] FIG1B is a schematic diagram of a communication system architecture to which the method according to an embodiment of the present application is applicable;

[0094] FIG1C is a schematic diagram of another communication system architecture to which the method according to an embodiment of the present application is applicable;

[0095] FIG1D is a schematic diagram of another communication system architecture to which the method according to an embodiment of the present application is applicable;

[0096] FIG1E is a schematic diagram of another communication system architecture to which the method according to an embodiment of the present application is applicable;

[0097] FIG2 is a schematic diagram of detection of a channel grid and a synchronization grid;

[0098] FIG3 is a schematic diagram of candidate SSB positions of an SSB pattern within a single time slot;

[0099] FIG4 is a schematic diagram of a terminal device misdetecting GSCN in an NTN communication system;

[0100] FIG5A is a schematic diagram of a flow chart of a communication method according to an embodiment of the present application;

[0101] FIG5B is a schematic flow chart of another communication method according to an embodiment of the present application;

[0102] FIG6A is a schematic diagram of a process of the method according to Embodiment 1 of the present application;

[0103] FIG6B is a schematic diagram of a terminal device detecting GSCN provided by the present application;

[0104] FIG7 is a schematic diagram of a flow chart of a method according to a second embodiment of the present application;

[0105] FIG8 is a schematic diagram of a flow chart of a method according to a third embodiment of the present application;

[0106] FIG9 is a schematic diagram of a sparse GSCN provided by this application;

[0107] FIG10 is a schematic diagram of another sparse GSCN provided by this application;

[0108] FIG11 is a schematic structural diagram of a communication device according to an embodiment of the present application;

[0109] FIG12 is a schematic structural diagram of another communication device according to an embodiment of the present application;

[0110] FIG13 is a schematic diagram of the device structure of a chip according to an embodiment of the present application. DETAILED DESCRIPTION

[0111] The method provided in the embodiment of the present application can be applied to non-terrestrial networks (NTN) communication scenarios. In the NTN communication scenario, non-terrestrial access network devices such as drones, high altitude platform stations (HAPS), and satellites can provide data transmission, voice communication and other services for terminals. In addition, the NTN system can also include other non-terrestrial access network devices, which is not limited in this application. The NTN communication scenario can also support various mobile communication systems, such as: new radio (NR) systems, long term evolution (LTE) systems or other communication systems such as future communication systems, which are not limited here. The method provided in the embodiment of the present application can be applied to, but not limited to, at least one of the following communication systems:

[0112] The fourth generation (4G) communication system (e.g., LTE system), the fifth generation (5G) communication system (e.g., NR system), or various future communication systems. The communication method provided in the embodiments of the present application can also be applied to vehicle-to-everything (V2X) communication, vehicle networking, autonomous driving, or assisted driving.

[0113] This application will present various aspects, embodiments, or features around systems including multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. Furthermore, combinations of these aspects may also be used.

[0114] To facilitate understanding, a communication system to which the embodiments of the present application can be applied is first described.

[0115] For example, FIG1A is a communication system to which an embodiment of the present application can be applied. As shown in FIG1A , the communication system may include at least one access network device (such as 110a, 110b, 110c in FIG1A ), and may also include at least one terminal (such as 120a-120g in FIG1A ). The terminal may be mobile or fixed. Each access network device can provide communication coverage for a specific geographical area and can communicate with terminals located within the coverage area. Access network devices and access network devices, access network devices and terminals, and terminals and terminals can be connected to each other in a wired or wireless manner. FIG1A is only a schematic diagram, and the communication system may also include other devices, such as wireless relay devices and wireless backhaul devices.

[0116] The embodiments of the present application may be applicable to a communication system that integrates a terrestrial communication system and a non-terrestrial communication system, which may also be referred to as an NTN communication system.

[0117] The terrestrial communication system may be, for example, an LTE system, a universal mobile telecommunications system (UMTS), a 5G communication system, or various future communication systems, etc., which are not limited here.

[0118] Compared to traditional communication systems, NTN communication systems have a wider coverage area and can overcome natural geographical obstacles such as oceans, deserts, and mountains. To overcome the shortcomings of traditional communication systems, NTN communication systems can serve as an effective supplement to them. Satellite communication systems can be divided into three types based on their orbital altitudes: geostationary Earth orbit (GEO) satellite communication systems, medium Earth orbit (MEO) satellite communication systems, and low Earth orbit (LEO) satellite communication systems. GEO satellite communication systems are also called synchronous orbit satellite systems. Generally, NTN has different channel characteristics compared to terrestrial communications (e.g., large transmission delays, large Doppler frequency deviations, etc.). For example, the round-trip delay of a GEO satellite communication system is 238 to 270 milliseconds (ms), while the round-trip delay of a LEO satellite communication system is 8 to 20 ms.

[0119] In NTN communications, NTN equipment can operate in two modes: transparent and regenerative. Based on the operating mode, NTN architectures can be categorized into two types: a transparent architecture, in which NTN equipment can act as relays or amplifiers, performing RF filtering and amplification, and regenerating physical layer signals. NTN equipment can be responsible for Layer 1 (L1) relaying, performing physical layer forwarding and remaining invisible to higher layers. A regenerative architecture, in which NTN equipment performs the processing functions of access network equipment. For example, satellites operating in regenerative mode can be categorized as regenerative satellites without inter-satellite links (ISLs) between satellites, regenerative satellites with ISLs (Xn interfaces), and regenerative satellites with distributed unit (DU) processing functions of access network equipment. In this scenario, the satellites function as DUs.

[0120] The NTN communication system described in this application may have multiple architectures, for example, any one of Architectures 1 to 4.

[0121] Architecture 1: Figure 1B shows a schematic diagram of an NTN communication system architecture that can be applied in an embodiment of the present application. The NTN communication system architecture can be a transparent satellite communication architecture. In the architecture shown in Figure 1B, the terminal device can communicate with the 5G core network (CN) through the access network, and then connect to the data network (DN) through the 5G CN. The satellite and the NTN gateway can serve as relay devices between the terminal device and the access network device or as the remote radio unit (RRU) of the access network device. The functions of the satellite are: radio frequency filtering, frequency conversion and amplification, that is, the satellite mainly acts as an L1 relay to regenerate the physical layer number and does not have other higher protocol layers. In the transparent satellite communication architecture, the link between the satellite and the terminal device is called a service link, and the link between the satellite and the NTN gateway or base station can be called a feeder link.

[0122] Architecture 2: Figure 1C shows a schematic diagram of another NTN communication system architecture applicable to embodiments of the present application. This NTN communication architecture can be a regenerative communication architecture. In the architecture shown in Figure 1C, the satellite can serve as an access network device, forming an access network with the NTN gateway and communicating with the core network through the NTN gateway. The satellite radio interface (SRI) interface is the feeder link between the NTN gateway and the satellite. In Figure 1C, the SRI interface can be used as part of the next generation network (NG) interface to implement communication interaction between the satellite base station and the core network. In addition, the satellite can also provide wireless access services for terminal devices. Figure 1C exemplifies a regenerative satellite architecture without intersatellite links, but with the processing functions of a base station. In this architecture, the satellite serves as a base station.

[0123] Architecture 3: Figure 1D illustrates another NTN communication system architecture applicable to embodiments of the present application. This architecture features a regenerative satellite with inter-satellite links (ISLs) and base station processing capabilities. In this scenario, the satellite also functions as a base station, and an inter-satellite link (ISL) exists. In this regenerative architecture, the link between the satellite and the terminal device is called a service link, and the link between the satellite and the NTN gateway is called a feeder link.

[0124] Architecture 4: Figure 1E shows another NTN communication system architecture applicable to the embodiments of the present application, which has a regenerative satellite with DU processing function of the base station (NG-RAN with a regenerative satellite based on gNB-DU); in this scenario, the satellite acts as a DU.

[0125] In addition, the embodiments of the present application can also be applied to scenarios where a base station (gNB processed payload based on relay-like architectures) has integrated access and backhaul (IAB) functions, and the satellite serves as an integrated access and backhaul IAB. A structural diagram is not provided here.

[0126] It should be noted that Figures 1B, 1C, 1D, and 1E illustrate only one satellite and one NTN gateway. In actual use, an architecture with multiple satellites and / or multiple NTN gateways may be employed as needed. Each satellite may provide services to one or more terminal devices, each NTN gateway may correspond to one or more satellites, and each satellite may correspond to one or more NTN gateways, although this embodiment of the present application does not specifically limit this. Furthermore, Figures 1B, 1C, 1D, and 1E are merely examples of NTN communication architectures, which may also include other specific devices, and this application does not limit this.

[0127] In this application, a terminal may also be referred to as user equipment (UE), access terminal, subscriber unit, user station, mobile station, mobile station (MS), remote station, remote terminal, mobile device, user terminal, terminal equipment, wireless communication equipment, user agent or user device, etc.

[0128] A terminal can be a device that provides wireless communication capabilities, such as a handheld device or vehicle-mounted device with wireless connection capabilities. Currently, some examples of terminals include: mobile phones, satellite mobile terminals, cellular phones, smart phones, tablet computers, laptop computers, PDAs, mobile internet devices (MIDs), wearable devices (such as smart watches, smart bracelets, pedometers, smart glasses, etc.), vehicle-mounted devices (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point of sale (POS) machines, customer-premises equipment (CPE), wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, and wireless terminals in smart homes. The present invention also includes wireless terminals (e.g., refrigerators, televisions, air conditioners, electric meters, etc.) in a home, intelligent robots, robotic arms, 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 a wireless modem, flying devices (e.g., intelligent robots, hot air balloons, drones, airplanes), terminals in 5G networks, or terminals in future-evolved public land mobile networks (PLMNs), etc., which are not limited in the embodiments of the present application. As an example and not a limitation, in the embodiments of the present application, the terminal may also be a mobile terminal (MT) in an integrated access and backhaul (IAB) node. When the IAB node faces its parent node, it can be regarded as a terminal. In this case, the IAB node plays the role of an MT.For the convenience of introduction, the terminal device is used as an example to introduce the present application solution below. In actual application, the terminal device can also be replaced by the above-mentioned terminals or devices.

[0129] The embodiments of this application do not limit the form of the terminal device. The device used to implement the terminal function can be a terminal device; it can also be a device that can support the terminal device to implement the function, such as a module or a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In the embodiments of this application, the chip system can be composed of chips or can include chips and other discrete devices.

[0130] In this application, an access network device is a device that can provide wireless communication functions for a terminal device, and the terminal device can communicate with the core network device through the access network device. As a node in the wireless access network, the access network device can also be called a base station, a radio access network (RAN) node (or device), or an access point (AP). A communication system may include one or more access network devices, and the multiple access network devices may be nodes of the same type or different types. In some scenarios, the roles of the access network device and the terminal device are relative. For example, network element #A may be a helicopter or a drone, which can be configured as a mobile base station and access the RAN through network element #B. For those terminal devices that access the RAN through network element #A, network element #A is a base station; but for network element #B, network element #A is a terminal device.

[0131] In one possible scenario, the access network device may be a base station, a transmitting and receiving point (TRP), a transmitting point (TP), a base station in a future mobile communication system, a satellite, an IAB node, a mobile switching center, a high-altitude platform or a satellite, etc. The access network device may be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in a cloud RAN (CRAN) scenario. The access network device may also be a device that acts as a base station in sidelink communication, vehicle-to-vehicle communication, drone communication, or machine communication. Optionally, the access network device may also be a server, a wearable device, a vehicle or an on-board device, etc. For example, the access network device in V2X technology may be a road side unit (RSU).

[0132] In another possible scenario, multiple access network devices collaborate to assist the terminal in achieving wireless access, and different access network devices respectively implement part of the functions of the base station. For example, the access network device can be a centralized unit (CU), a distributed unit DU, a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or they can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It can be understood that the access network device can be a CU node, a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into an access network device in the access network RAN, or the CU can be divided into an access network device in the core network CN, without limitation.

[0133] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0134] In the embodiments of the present application, the form of the access network device is not limited. The device used to implement the functions of the access network device can be the access network device; it can also be a device that supports the access network device to implement the functions, such as a module or chip system. The device can be installed in the access network device or used in conjunction with the access network device.

[0135] Access network equipment and terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of access network equipment and terminal devices.

[0136] The communication system and business scenarios (or application scenarios) described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of network architecture and the emergence of new business scenarios (or new application scenarios), the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0137] The following is an explanation of the relevant terms and technologies involved in the embodiments of the present application. It should be noted that these explanations are intended to make the embodiments of the present application easier to understand and should not be regarded as limiting the scope of protection claimed by the present application.

[0138] 1) Initial access:

[0139] In this application, initial access may include cell search and random access.

[0140] Before accessing the network, a terminal device must perform a cell search. For example, a cell search can be performed when the terminal device is powered off and then on again. The purpose of a cell search is to enable the terminal device to achieve system time and frequency synchronization, thereby enabling the terminal device to read system information (such as information about the cell to be accessed, system bandwidth, and other cell broadcast information) and perform subsequent data transmission.

[0141] Random access is the process initiated by the terminal device to achieve uplink synchronization between the terminal device and the access network device after the two devices have achieved downlink synchronization. Random access can be divided into contention-based random access (also known as four-step random access) and non-contention-free random access (also known as two-step random access).

[0142] 2)SSB:

[0143] SSB is one of the most important pilot channels used in 5G. Its role is related to many aspects of terminal device access to a cell, such as cell search, beam measurement, beam selection, and beam recovery. For example, network equipment broadcasts beams in different directions to send SSBs to terminal devices for synchronization during the initial access phase. During this initial access phase, the satellite acts as a network device, sequentially scanning all beams and allocating random access resources to the terminal device.

[0144] Typically, the SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). That is, the SSB is composed of the PSS, SSS, and PBCH. The synchronization signals (PSS and SSS, or PSS and SSS sequences) can be used by terminal devices for downlink synchronization and to obtain the cell's identity (ID). Downlink synchronization can include frequency synchronization and time synchronization. The PBCH can be used by terminal devices to obtain information about the cell they are accessing.

[0145] It should be noted that in the embodiments of the present application, a sequence may also be referred to as a symbol sequence, a sequence of symbols, etc. A sequence of XXX may also be referred to as a symbol sequence corresponding to XXX, a sequence of symbols corresponding to XXX, a sequence corresponding to XXX, a sequence of symbols constituting XXX, a sequence constituting XXX, etc. For example, N sequences of a synchronization signal may also be referred to as N symbol sequences corresponding to the synchronization signal, N sequences of symbols corresponding to the synchronization signal, N sequences corresponding to the synchronization signal, N sequences of symbols constituting the synchronization signal, N sequences of symbols constituting the synchronization signal, N sequences constituting the synchronization signal, etc.

[0146] 3) Cell identification (ID): It can also be called physical cell identities (PCI). In wireless communication, the physical layer uses the physical cell ID (denoted as N ID(cell) ) to distinguish different cells. At present, all physical cell IDs can be divided into multiple groups, one group corresponds to a group identifier, and the group identifier can be called the second identifier (denoted as N ID(1) ), each group includes multiple different group identifiers, and the group identifier can also be called the first identifier (denoted as N ID(2) ). A physical cell ID can be determined based on a second identifier and a first identifier. Exemplarily, the physical cell ID can be calculated using the following formula: N ID(cell) =3N ID(1) +N ID(2) .

[0147] First identifier N ID(2) It can be carried in PSS, and the second identifier can be carried in SSS.

[0148] It should be understood that the naming of the above-mentioned identifiers is only an exemplary naming and is not specifically limited in this application.

[0149] 4) Channel raster:

[0150] In the NR system, the global frequency grid is defined as a set of radio frequency (RF) reference frequencies, which are used in signaling to identify the frequency positions of RF channels, SSBs, and other elements. The frequency range of the global frequency grid is 0 to 100 GHz, and the RF reference frequency is specified by the NR absolute RF channel number within the range of the global frequency grid. The channel grid is defined as a subset of RF reference frequencies, which is mainly used to identify the frequency domain position of the RF channel in the uplink and downlink. In each operating bandwidth, different frequency subsets from the global frequency grid are used to adapt to different operating frequency bands.

[0151] 5) Synchronization raster and global synchronization channel number (GSCN):

[0152] As shown in Figure 2, the channel grid can be used to place data, reference signals (RS), control channels, etc. Since the NR cell bandwidth is very wide, blind detection according to the channel grid will cause the terminal device access speed to be very slow. In order to enable the terminal device to search for the cell (detect SS / PBCH) more quickly, the NR specifies the center frequency and interval of the SSB, which are called the synchronization grid: 1200KHz, 1.44MHz and 17.28MHz respectively. In the NR system, when the explicit signaling notifying the location of the synchronization block does not exist, the synchronization grid indicates the frequency position of the synchronization block that the terminal device can use to obtain system information. In this way, the terminal device can scan the frequency according to the synchronization grid after powering on to achieve frequency domain synchronization with the network equipment.

[0153] For synchronization, all SSBs are aligned with the synchronization grid (ie, SSBs are placed according to the synchronization grid). The synchronization grid is different from the channel grid. It is a set of absolute frequency domain positions, and each frequency domain position has a unique number (ie, GSCN).

[0154] Frequency position of SSB SS REF The GSCN is the number corresponding to the center frequency of the SSB. The relationship between the two is shown in Table 1. The SSB is arranged according to the synchronization grid, and one GSCN frequency point number corresponds to one synchronization grid.

[0155] Table 1

[0156] In addition, existing protocols specify the sub-carrier spacing (SCS) and SSB pattern of SSB corresponding to different frequency bands, as well as the GSCN range and interval of the synchronization grid.

[0157] The protocol divides different frequency ranges into different operating bands. These bands have different RF performance requirements, and define different subcarrier spacing, duplex modes, and application scenarios. As shown in Table 2 below, different operating bands define different channel bandwidths and synchronization grids.

[0158] Table 2

[0159] During initial access, the UE first searches for cell synchronization by searching for the SSB. During the SSB search, the UE first determines the SSB mode case and the GSCN range and interval of the candidate synchronization grid based on the operating frequency band and SCS.

[0160] Table 3 below shows the definition of synchronization grids for different operating frequency bands. As shown in Table 3 below, different SCS, SSB modes, and GSCN ranges are defined in different operating frequency bands.<step size> Indicates the interval or distance between the applied GSCN entries. In this embodiment of the application,<step size> It can indicate the interval or distance between adjacent GSCNs used / detected by the UE.

[0161] Table 3

[0162] As shown in Table 3, according to the definitions shown in Table 3, the SSB mode of different cases is defined as follows:

[0163] For SSB in a half-frame, the first symbol index of the candidate SSB varies with different SCSs, and index 0 represents the first symbol of the first time slot in the half-frame.

[0164] Case A, SCS is 15kHz: the first symbol index of the candidate SSB is {2,8}+14·n;

[0165] For channel access in the licensed spectrum: when the carrier frequency is less than or equal to 3 GHz, n = 0, 1; when the carrier frequency is in the FR1 band and greater than 3 GHz, n = 0, 1, 2, 3.

[0166] For channel access in unlicensed spectrum, n = 0, 1, 2, 3, 4.

[0167] Case C, SCS is 30kHz: the first symbol index of the candidate SSB is {2,8}+14·n;

[0168] For channel access in the licensed spectrum, this includes the following:

[0169] For paired spectrum (frequency division duplexing (FDD)): when the carrier frequency is less than or equal to 3 GHz, n = 0, 1; when the carrier frequency is in the FR1 band and greater than 3 GHz, n = 0, 1, 2, 3.

[0170] For unpaired spectrum (time division duplexing (TDD)): when the carrier frequency is less than 1.88 GHz, n = 0, 1; when the carrier frequency is in the FR1 band and greater than or equal to 1.88 GHz, n = 0, 1, 2, 3.

[0171] For shared channel access in unlicensed spectrum, n = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

[0172] The candidate SSB positions of the SSB pattern corresponding to Case C in a single time slot are shown in Figure 3. Figure 3 illustrates the SSB pattern of Case C when SCS = 30kHz. The pattern (pattern) of the SS / PBCH block burst set (which can also be understood as position distribution) is cyclical in units of 1 time slot. In other words, taking 1 time slot as a unit, in each time slot, the relative position of the SS / PBCH block in the SS / PBCH block pattern is the same. It can also be understood that in different SS / PBCH block burst sets, the SS / PBCH blocks with the same relative position have the same offset relative to the starting position of the SS / PBCH block burst set in which they are located. Among them, the candidate index can also be understood as the candidate position for SSB transmission, or transmission opportunity, etc.

[0173] The above introduces some noun / term concepts involved in the embodiments of this application. The following introduces the technical issues involved in the embodiments of this application.

[0174] In NTN communication systems, the Doppler frequency shift is much greater than that in terrestrial communication systems. In addition to Doppler frequency shift, frequency deviations may also be caused by satellite motion, terminal motion, and local crystal oscillator drift.

[0175] For example, as shown in Figure 4, the actual frequency f of the satellite transmitting SSB is 2172.15 MHz, and the corresponding GSCN is 5430. Due to the presence of Doppler frequency offset, after a 24 ppm Doppler frequency shift, the frequency of the SSB signal transmitted by the satellite arriving at the UE antenna port is 2172.1 MHz. However, due to a 5 ppm deviation in the local crystal oscillator, the UE believes that the actual frequency position of 2172.05 MHz is actually 2172.06 MHz. Based on this, the UE believes that the GSCN of the detected SSB frequency is 5429, resulting in a frequency misalignment. The misalignment of the SSB GSCN will cause frequency deviation in downlink synchronization, thereby affecting synchronization performance and subsequent decoding accuracy, that is, affecting subsequent communication performance.

[0176] In view of the above problems, an embodiment of the present application proposes a communication method, which can effectively improve the accuracy of the terminal device in determining the global synchronization channel number GSCN. The subsequent terminal device performs downlink synchronization with the network device based on the determined GSCN, which can effectively improve the accuracy of downlink synchronization and thereby ensure subsequent communication performance.

[0177] It should be understood that this application is not limited to NTN communication scenarios. NTN communication is only one application scenario and may also be applicable to other scenarios (such as non-NTN communication scenarios, communication scenarios of future evolution systems, etc.). In addition, in this application, the names of the various messages (or information) in the following processes are merely examples. As communication technology evolves, the names of the various messages (or information, etc.) in the following processes may change. However, regardless of how the names change, as long as their meanings are the same as the functions or meanings of the messages (or information, etc.) in this application, they fall within the scope of protection of this application.

[0178] In this application, "sending information to... (terminal device)" can be understood as the destination of the information being the terminal device, and can include directly or indirectly sending information to the terminal device. "Receiving information from... (terminal device)" can be understood as the source of the information being the terminal device, and can include directly or indirectly receiving information from the terminal device. The information may be processed as necessary between the source and destination of the information, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be understood similarly and will not be repeated here.

[0179] The following is a corresponding introduction to the solutions of the embodiments of the present application.

[0180] The present application embodiment provides a communication method, which can be applied to but not limited to the communication system architecture shown in Figures 1A to 1E. The method can be executed by a terminal device (which can also be a network device), or by a module (such as a processor, a chip, or a chip system, etc.) applied to a terminal device (which can also be a network device), or by a logical node, a logical module or software that can realize all or part of the terminal device (which can also be a network device) function; In addition, the present application does not specifically limit the specific structure of the execution subject (such as a terminal device, a network device) of the method provided in the embodiment of the present application and the number of each execution subject, as long as it can be communicated according to the method provided in the embodiment of the present application by running a program that records the code of the method provided in the embodiment of the present application. For ease of description, the interaction between a terminal device and a network device is used as an example for explanation. The order of the steps in the following each process is only an example. In actual application, the steps in each process can adjust the execution order, and all or part of the steps can be adaptively executed.

[0181] Referring to FIG5A , the specific process of the method may include the following:

[0182] S501A: The terminal device determines that the current global synchronization channel number GSCN is the first GSCN.

[0183] In one possible implementation, the terminal device determines that the current GSCN is the first GSCN, which may include: first determining the candidate GSCN area of ​​the terminal device (here refers to the GSCN range corresponding to the working frequency band of the above-mentioned UE) based on the working frequency band and subcarrier spacing corresponding to the terminal device, the candidate GSCN area includes at least one GSCN, and each GSCN in the at least one GSCN corresponds to the frequency position of an SSB; the terminal device then performs SSB detection based on the at least one GSCN, and determines the first GSCN when the SSB of the network device is detected as the current GSCN.

[0184] For example, the GSCN area (or GSCN range) corresponding to UE1 is 2999~3013. UE1 traverses and searches all GSCN values ​​2999~3013 until it finds the SSB sent by the network device. At this time, the corresponding GSCN (ie, the first GSCN) is 3000, and UE1 determines 3000 as the current GSCN.

[0185] S502A: The network device generates first information, where the first information is used to indicate information associated with a second GSCN, where the second GSCN is the GSCN for the network device to send SSB.

[0186] In the above description, the second GSCN can be understood as the actual GSCN used by the network device to send the SSB, which may be referred to as the actual GSCN or the real GSCN hereinafter.

[0187] In an embodiment of the present application, the network device can be an access network device in a terrestrial communication system (such as a base station), or it can be an access network device in a non-terrestrial communication system, such as a satellite. The satellite can have some or all of the functions of a terrestrial access network device (such as a base station), and there is no limitation on this.

[0188] In the embodiment of the present application, the first information is used to indicate information associated with the second GSCN, and may include but is not limited to the following specific implementations:

[0189] Implementation method 1: There is a correspondence between the GSCN and the physical cell identifier PCI; then the first information can be used to determine the first PCI.

[0190] In an embodiment of the present application, the correspondence between GSCN and PCI may refer to the existence of one or more association relationships between GSCN and PCI, that is, if one of the information is known, the other information can be deduced based on the association relationship between the two. For example, if PCI is known, part or all of the corresponding GSCN information can be deduced based on the association relationship between GSCN and PCI. In addition, the correspondence between GSCN and PCI can be pre-set or established, and both the network device side and the terminal device side can know the correspondence. The correspondence between GSCN and PCI can also be pre-negotiated or agreed upon between the network device side and the terminal device side, and this application does not limit this.

[0191] For example, the correspondence between GSCN and PCI may include but is not limited to the following:

[0192] 1. There is an odd-even correspondence between GSCN and PCI. That is, the parity of GSCN and PCI is opposite or opposite. For example, when PCI is odd, the corresponding GSCN is even; and vice versa, when PCI is even, the corresponding GSCN is odd.

[0193] The existence of an even-odd correspondence between GSCN and PCI is applicable to, but not limited to, scenarios where the frequency offset between the network device and the terminal device does not exceed one GSCN interval.

[0194] 2. There is an odd-odd correspondence between GSCN and PCI, or an even-even correspondence, that is, the parity of the GSCN and PCI is the same. For example, when the PCI is odd, the corresponding GSCN is odd; and when the PCI is even, the corresponding GSCN is even.

[0195] In addition, there may be other characteristic correspondences or other forms of correspondences between GSCN and PCI, which are not listed one by one in this application. For example, the correspondence between GSCN and PCI can be a preset formula, numerical value, symbol, table, etc. For example, the difference between GSCN and PCI is uniformly preset, or the GSCN and PCI satisfy a preset function, or the correspondence between GSCN and PCI can be specified by a preset table, etc.

[0196] In a possible implementation, for implementation method 1, the first information is a primary synchronization signal PSS and a secondary synchronization signal SSS sequence in the SSB, and the PSS and SSS sequences are used to determine the first PCI.

[0197] Implementation method 2: The first information is used to indicate part or all of the information of the second GSCN.

[0198] In implementation mode 2, part of the information of the second GSCN may be, but is not limited to, any of the following:

[0199] (1) At least one digit of the second GSCN.

[0200] In an embodiment of the present application, at least one digit of the second GSCN can be a single digit (e.g., a unit digit), or two digits (e.g., a first digit and a unit digit, or a tens digit and a unit digit), or more digits in the second GSCN, without specific limitation.

[0201] In addition, when the first information is used to indicate information of at least one digit of the second GSCN, the information of the at least one digit may be a different presentation form of the at least one digit, such as a decimal number or a binary number of each digit.

[0202] Exemplarily, the first information is used to indicate the binary number of the first digit of the second GSCN and the binary number of the last digit (ie, the unit digit) of the second GSCN.

[0203] For example, if the second GSCN is 5430, the first digit of the second GSCN is 5 and the last digit is 0, the binary representation of the first digit 5 ​​is 0101, and the binary representation of the last digit 0 is 0000. Alternatively, the first digit of the second GSCN is 5 and the last digit is 0 to form the value 50, and the binary representation of 50 is 110010.

[0204] In one possible implementation, the first information is MIB information in an SSB sent by the network device, and 8 bits are added to the MIB information, where the added 8 bits are represented as 0101 0000 or 0000 0101. In another possible implementation, the first information is MIB information in an SSB sent by the network device, and 6 bits are added to the MIB information, where the added 6 bits are represented as 110010.

[0205] (2) The value of the first parameter M corresponding to the second GSCN.

[0206] According to GSCN=3N+(M-3) / 2 recorded in Table 1 above, it can be seen that the value of GSCN is jointly determined by N and M (ie, the first parameter in this application).

[0207] In an embodiment of the present application, all information of the second GSCN may be, but is not limited to: all digits of the second GSCN (ie, the second GSCN value), or the binary number of the second GSCN, or the M and N values ​​corresponding to the second GSCN.

[0208] In one possible implementation, the terminal device receives an SSB sent from a network device, and the first information is carried in a master system information block MIB of the SSB.

[0209] For example, 2 bits of information may be added to the MIB information to indicate the value of the first parameter M corresponding to the second GSCN.

[0210] S503A: The network device sends first information, and the terminal device receives the first information accordingly.

[0211] In one possible implementation, the network device sends an SSB to the terminal device based on the second GSCN, where the SSB carries / includes the first information. Accordingly, the terminal device receives the SSB and obtains the first information therefrom.

[0212] S504A: The terminal device determines a third GSCN based on the first information and the first GSCN.

[0213] In the above, the third GSCN may refer to a GSCN determined by the terminal device based on the first GSCN detected by itself and the first information, and the terminal device subsequently performs downlink synchronization and communication with the network device based on the third GSCN.

[0214] In one possible implementation, corresponding to the first implementation in S501A, the terminal device determines the third GSCN based on the first information and the first GSCN, which may include the following situations and corresponding determination methods:

[0215] Case 1: The first GSCN and the first PCI conform to this correspondence: the value of the third GSCN is equal to the value of the first GSCN.

[0216] Case 2: The first GSCN and the first PCI do not conform to the correspondence: from at least one candidate GSCN, determine the target GSCN that conforms to the correspondence with the first PCI, and the distance between the center frequency position of the SSB corresponding to the target GSCN and the center frequency position of the SSB detected by the terminal device for the network device is the smallest, and the value of the third GSCN is equal to the value of the target GSCN; wherein, the at least one candidate GSCN is determined by the working frequency band corresponding to the terminal device.

[0217] In one possible implementation, corresponding to (1) under the second implementation in S501A, the terminal device determines the third GSCN based on the first information and the first GSCN, which may include the following situations and corresponding determination methods:

[0218] Case 1: the value of at least one digit in the same position in the first GSCN is consistent with the value of at least one digit in the second GSCN: the value of the third GSCN is equal to the value of the first GSCN;

[0219] Case 2: the value of at least one digit in the same position in the first GSCN is inconsistent with the value of at least one digit in the second GSCN: the terminal device adjusts the value of the first GSCN according to at least one digit of the second GSCN to obtain the adjusted first GSCN, and the value of the third GSCN is equal to the value of the adjusted first GSCN.

[0220] In one possible implementation, the UE receives an SSB from a network device, that is, the UE receives a PBCH, parses the MIB information, and adds a new bit parameter in the MIB information to indicate the first and last digits of the second GSCN; then, based on the first and last digits of the second GSCN, the UE can compare the first and last digits of the first GSCN with the first and last digits of the second GSCN:

[0221] If the comparisons are consistent, the UE confirms that the first GSCN is correct and the value of the third GSCN is equal to the value of the first GSCN.

[0222] If the comparison is inconsistent, that is, the first digit of the first GSCN is not equal to the first digit of the second GSCN, and / or the last digit of the first GSCN is not equal to the last digit of the second GSCN, the UE determines that the first GSCN is incorrect, and then the UE can modify the first GSCN based on the first digit and / or last digit of the second GSCN. Specific modifications may include but are not limited to the following situations:

[0223] Case 1: The first digit of the first GSCN is equal to the first digit of the second GSCN, but the last digit of the first GSCN is not equal to the last digit of the second GSCN: the UE modifies the last digit of the first GSCN to the last digit of the second GSCN to obtain the adjusted first GSCN, and the value of the third GSCN is equal to the value of the adjusted first GSCN.

[0224] For example, the first GSCN is 5431, that is, the first digit of the first GSCN is 5 and the last digit is 1; and the first digit of the second GSCN indicated by the network device is 5 and the last digit is 0, then the UE modifies the last digit 1 of the first GSCN to 0, and the adjusted first GSCN is 5430. The UE determines that the value of the third GSCN is equal to 5430.

[0225] Case 2: The first digit of the first GSCN is not equal to the first digit of the second GSCN: The UE selects a target GSCN from the candidate GSCN area (i.e., the GSCN range corresponding to the UE's working frequency band). The value of the third GSCN is equal to the value of the target GSCN. The target GSCN should meet the following conditions:

[0226] (1) The first digit of the target GSCN is equal to the first digit of the second GSCN; (2) The last digit of the target GSCN is equal to the last digit of the second GSCN; (3) The absolute difference in frequency between the target GSCN and the first GSCN is the smallest.

[0227] For example, the first GSCN is 3000, the first digit of the second GSCN is 2, and the last digit is 9; the GSCN area (or GSCN range) corresponding to the UE is 2999-3013. The UE can select a GSCN (i.e., the target GSCN) from 2999-3013, which is 2999. The first digit of this GSCN is 2, the last digit is 9, and the frequency position is closest to 3000. Therefore, the UE determines that the value of the third GSCN is equal to 2999.

[0228] In one possible implementation, corresponding to (2) under the second implementation in S501A above, the terminal device determines the third GSCN based on the first information and the first GSCN, which may include the following:

[0229] First, determine the value of the first parameter M and the value of the second parameter N corresponding to the first GSCN; the first parameter M and the second parameter N can be used to characterize the center frequency position of the SSB corresponding to the GSCN and the GSCN;

[0230] If the value of the first parameter M corresponding to the first GSCN is equal to the value of the first parameter M corresponding to the second GSCN, the value of the third GSCN is equal to the value of the first GSCN;

[0231] If the value of the first parameter M corresponding to the first GSCN is not equal to the value of the first parameter M corresponding to the second GSCN, the value of the first parameter M corresponding to the first GSCN is updated to the value of the first parameter M corresponding to the second GSCN to obtain the updated value of the first parameter M corresponding to the first GSCN; then, based on the updated value of the first parameter M corresponding to the first GSCN and the value of the second parameter N corresponding to the first GSCN, the updated value of the first GSCN is determined, and the value of the third GSCN is equal to the updated value of the first GSCN.

[0232] For example, the first GSCN is 3000, and the N value corresponding to the first GSCN of 3000 is 1000, and the M value is 3. If the MIB information (i.e., the first information) in the SSB received by the UE indicates that the M value corresponding to the second GSCN is 1, the UE modifies the M value corresponding to the first GSCN to 1, and then recalculates the first GSCN to 2999 based on the N value of 1000, the M value of 1, and the formula GSCN=3N+(M-3) / 2. Therefore, the UE determines that the value of the third GSCN is equal to the recalculated value of the first GSCN, 2999.

[0233] In summary, an embodiment of the present application provides a communication method, which includes: a terminal device determines that the current GSCN is a first GSCN; then the terminal device receives first information from a network device, the first information is used to indicate information associated with a second GSCN, and the second GSCN is the GSCN for the network device to send SSB; the terminal device determines a third GSCN based on the first GSCN and the first information. In this method, the network device can provide the terminal device with information associated with the second GSCN (i.e., the actual GSCN) of the network device, and the terminal device can determine the third GSCN by combining the associated information and the first GSCN detected by itself. This can effectively improve the accuracy of the third GSCN, so that the subsequent terminal device can perform downlink frequency synchronization with the network device based on the third GSCN with higher accuracy, thereby ensuring subsequent communication performance.

[0234] The embodiment of the present application also provides another communication method, such as the method shown in Figure 5B below, which can be applied to but not limited to the communication system architecture shown in Figures 1A to 1E. The execution subject of the method and the number of execution subjects can correspond to the relevant introduction of the execution subject and the number of execution subjects in Figure 5A above. In addition, no further details are given. As long as it is possible to communicate according to the method provided in the embodiment of the present application by running a program that records the code of the method provided in the embodiment of the present application. In addition, the method (the method shown in Figure 5B below) can be implemented or executed independently, or it can be implemented or executed in combination with all or part of the steps described in Figure 5A above. For example, the method shown in Figure 5B can be a possible implementation of step S501A in the method flow shown in Figure 5A above. For ease of description, the interaction between a terminal device and a network device is used as an example for explanation below. The order of steps in the following various processes is only an example. In actual applications, the steps in the following various processes can adjust the execution order, and all or part of the steps can be adaptively executed. Referring to Figure 5B, the specific process of the method may include the following:

[0235] S501B: The network device determines a second GSCN from the first GSCN area.

[0236] In an embodiment of the present application, the network device can be an access network device in a terrestrial communication system (such as a base station), or it can be an access network device in a non-terrestrial communication system, such as a satellite. The satellite can have some or all of the functions of a terrestrial access network device (such as a base station), and there is no limitation on this.

[0237] S502B: The terminal device determines the first GSCN area.

[0238] In the embodiment of the present application, S501B and S502B may be executed synchronously or asynchronously, and the order in which S501B and S502B are executed is not specifically limited.

[0239] S503B: The network device sends an SSB based on the second GSCN. Correspondingly, the terminal device receives the SSB from the network device based on the first GSCN area.

[0240] In each of the above steps, the location and boundary of the first GSCN area (or referred to as the first GSCN range) are consistent with the location and boundary of the second GSCN area (or referred to as the second GSCN range). The second GSCN area can be associated with the working frequency band corresponding to the terminal device, that is, the second GSCN area can be determined according to the working frequency corresponding to the terminal device. In an embodiment of the present application, the first GSCN area and the second GSCN area can be regarded as the same GSCN area or the same GSCN range.

[0241] The first GSCN area and the second GSCN area mentioned above are introduced in detail below.

[0242] The first GSCN area and the second GSCN area respectively include at least two GSCNs, and the interval between two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between two adjacent GSCNs to be detected in the second GSCN area.

[0243] In the embodiment of the present application, the interval between two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between two adjacent GSCNs to be detected in the second GSCN area, which may include the following specific implementation methods:

[0244] Implementation method 1: the interval between two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between two adjacent GSCNs to be detected in the second GSCN area: the frequency interval between two adjacent GSCNs to be detected in the first GSCN area is greater than the frequency interval between two adjacent GSCNs to be detected in the second GSCN area.

[0245] In one possible implementation, the center frequency position of the SSB corresponding to the GSCN in the second GSCN area may be represented by the following information:

[0246] The first parameter M, the first step value of the first parameter M, the second parameter N, the step value of the second parameter N;

[0247] The interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the second GSCN area is associated with the first step value and / or the step value of the second parameter N, and N and M are positive integers.

[0248] In the above, the second GSCN area can be regarded as a GSCN range defined in the prior art, and the GSCN range can be associated with the operating frequency band corresponding to the terminal device. In addition, the center frequency position of the SSB corresponding to each GSCN in the second GSCN area can be determined in the same manner as in the prior art.

[0249] In the above, the center frequency position of the SSB corresponding to the GSCN in the first GSCN area can be represented by the following information:

[0250] The first parameter M, the second step value of the first parameter M, the second parameter N, the step value of the second parameter N;

[0251] Among them, the interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the first GSCN area is associated with the second step value and / or the step value of the second parameter N, the second step value is greater than the first step value of the first parameter M, and N and M are positive integers.

[0252] According to the above, by increasing the step value of the first parameter M, when the terminal device searches for the SSB of the network device based on the first GSCN area, the interval between the center frequency positions of the SSBs of the two adjacent GSCNs to be detected in the first GSCN area is larger. In this way, the probability of the terminal device misdetecting the GSCN due to frequency deviation will be effectively reduced.

[0253] In the embodiment of the present application, when setting the second step value of the first parameter M, it is necessary to ensure that M has at least one feasible value.

[0254] The feasible value of M means that the value of M can ensure that the center frequency position of the SSB corresponding to the GSCN in the first GSCN area and the full-bandwidth downlink center frequency position of the transmission channel (such as the physical downlink shared channel (PDSCH) or the physical downlink control channel (PDCCH)) are separated by an integer multiple of 15kHz.

[0255] The first GSCN area introduced in the first implementation method can be used on the terminal device side or on the network device side.

[0256] Implementation method 2: the interval between two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between two adjacent GSCNs to be detected in the second GSCN area.

[0257] In the second implementation, compared with the second GSCN area, the GSCN range corresponding to the first GSCN area remains unchanged, but the interval between two adjacent GSCNs detected by the terminal device based on the first GSCN area becomes larger.

[0258] In a possible implementation, the second GSCN area corresponds to the first step distance, and the first step distance is used to represent the absolute difference between two adjacent GSCNs to be detected in the second GSCN area.

[0259] In the above description, the second GSCN area can be regarded as a GSCN range defined in the prior art, and the GSCN range can be associated with the operating frequency band corresponding to the terminal device. In addition, the first step distance corresponding to the second GSCN area can be the same as that in the prior art.

[0260] In the above, the first GSCN area corresponds to the second step distance, and the second step distance is used to represent the absolute difference between two adjacent GSCNs to be detected in the first GSCN area. The value of the second step distance is greater than the value of the first step distance corresponding to the second GSCN area.

[0261] According to the above, when the terminal device searches / detects the SSB of the network device according to the second step distance corresponding to the first GSCN area, the interval between the two adjacent GSCNs to be detected is large, so the probability of the terminal device misdetecting the GSCN due to frequency deviation will be effectively reduced.

[0262] S504B: The terminal device determines the first GSCN corresponding to the SSB received from the network device as the current global synchronization channel number GSCN.

[0263] Corresponding to the above-mentioned implementation method 1: In one possible implementation method, the terminal device performs detection based on the first GSCN area, searches for the SSB from the network device, and determines the first GSCN corresponding to the received SSB as the current GSCN; wherein, the frequency interval between the two adjacent GSCNs to be detected in the first GSCN area is greater than the frequency interval between the two adjacent GSCNs to be detected in the second GSCN area.

[0264] For example, the second GSCN range (i.e., the second GSCN area) corresponding to the UE's working frequency band is 2999~3013, and the UE needs to traverse and detect each GSCN value of {2999, 3000, 3001, ..., 3011, 3012, 3013}, where the center frequency interval of the SSB to be detected between 2999 and 3000, the center frequency interval of the SSB to be detected between 3000 and 3001, ...., and the center frequency interval of the SSB to be detected between 3012 and 3013 are all Δf, Δf=2*50kHz=100kHz, and 50kHz is the first step value of M.

[0265] The first GSCN range (i.e., the first GSCN area) is 2999 to 3013. The UE needs to traverse and detect each GSCN {2999, 3000, 3001, ..., 3011, 3012, 3013}, where the center frequency interval of the SSBs to be detected between 2999 and 3000, the center frequency interval of the SSBs to be detected between 3000 and 3001, ..., and the center frequency interval of the SSBs to be detected between 3012 and 3013 are all Δf', Δf' = 2*100kHz = 200kHz, and 100kHz is the second step value of M. It can be seen that compared with the center frequency interval of the SSBs to be detected between two adjacent GSCNs in the second GSCN range, the center frequency interval of the SSBs to be detected between two adjacent GSCNs in the first GSCN range is larger. In this way, when the UE searches / detects the SSBs of network devices in the first GSCN range, the probability of misdetecting the GSCN due to frequency offset is effectively reduced.

[0266] Corresponding to the above-mentioned implementation method 2: In one possible implementation method, the terminal device can perform detection based on the second step distance corresponding to the first GSCN area, search for the SSB from the network device, and determine the first GSCN corresponding to the received SSB as the current GSCN; wherein the value of the second step distance corresponding to the first GSCN area is greater than the value of the first step distance corresponding to the second GSCN area.

[0267] For example, the second GSCN range (i.e., the second GSCN area) corresponding to the UE's operating frequency band is 2999-3013, i.e., {2999, 3000, 3001, ..., 3011, 3012, 3013}. The step size corresponding to the second GSCN range is 1, i.e., the interval or spacing between two adjacent GSCNs to be detected is 1. Therefore, the UE needs to traverse each GSCN value from 2999 to 3013 to detect the SSB of the network device.

[0268] The first GSCN range (i.e., the first GSCN area) is 2999 to 3013, i.e., {2999, 3000, 3001, ..., 3011, 3012, 3013}. The step size corresponding to the first GSCN range is 4, meaning the interval or spacing between two adjacent GSCNs to be detected is 4. Therefore, the terminal device needs to detect the SSB of the network device according to {2999, 3003, 3007, 3011}. Therefore, when the UE searches for the SSB of the network device in the first GSCN range using the step size of 4 corresponding to the first GSCN range, the probability of the terminal device misdetecting the GSCN due to frequency offset is effectively reduced. Furthermore, the number of GSCNs detected by the UE is relatively reduced, which shortens the time it takes for the UE to perform detection, thereby reducing the latency of the UE's initial access.

[0269] In summary, an embodiment of the present application provides a communication method, which includes: a terminal device determines a first GSCN area; the range of the first GSCN area is the same as the range of the second GSCN area, the second GSCN area is determined by the working frequency band corresponding to the terminal device, the first GSCN area and the second GSCN area respectively include at least two GSCNs, and the interval between the two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between the two adjacent GSCNs to be detected in the second GSCN area; the terminal device receives an SSB from a network device based on the first GSCN area, and determines the first GSCN corresponding to the received SSB as the current GSCN. In this method, compared with the interval between the two adjacent GSCNs to be detected in the second GSCN area, the interval between the two adjacent GSCNs to be detected in the first GSCN area is larger, which can effectively reduce the probability of subsequent terminal devices misdetecting GSCNs in the presence of frequency deviation, improve the accuracy of terminal devices detecting GSCNs, thereby improving the accuracy of subsequent downlink frequency synchronization, and thus ensuring subsequent communication performance.

[0270] The solution described in FIG. 5A will be introduced below through several specific implementations.

[0271] Implementation Method 1: For example, in an NTN system at an orbital altitude of 600 km, the satellite base station moves at a speed of 7.6 km / s, with a maximum transmission distance of approximately 900 km. Its maximum Doppler shift is approximately 70 kHz, while the minimum distance between two adjacent GSCNs is 100 kHz. Therefore, due to Doppler shift, misdetected GSCNs can fluctuate by one position, meaning an odd-numbered GSCN can be misdetected as an even-numbered GSCN, or vice versa. This demonstrates the existence of an odd-even correspondence between GSCNs and PCIs: for example, an odd-numbered PCI should correspond to an even-numbered GSCN, and an even-numbered PCI should correspond to an odd-numbered GSCN.

[0272] Based on the above, in implementation mode one, taking the existence of an odd-even correspondence between the first GSCN and the first PCI as an example, it is introduced how to use this correspondence to assist the terminal device UE in distinguishing the GSCN and determining the third GSCN for subsequent downlink synchronization and communication. The following is a detailed introduction to implementation mode one using an example in which the network device is a satellite with all the functions of a ground base station. This implementation mode one can be executed by a satellite (which can also be a UE), or by a module (such as a processor, chip, or chip system, etc.) applied to a satellite (which can also be a UE), or by a logical node, logical module or software that can realize all or part of the satellite (which can also be a UE) functions. As shown in Figure 6A, the specific process of implementation mode one may include the following:

[0273] S601A: The satellite transmits an SSB, and the UE receives the SSB.

[0274] S602A: The UE determines that the current GSCN is the first GSCN.

[0275] In one possible implementation, the UE determines that the current GSCN is the first GSCN, including: the UE determines the frequency band range for searching the SSB according to the corresponding working frequency band, and searches for the SSB on the corresponding synchronization grid, that is, the UE searches / detects the SSB sent by the satellite based on the GSCN range corresponding to its own working frequency band; when the UE receives / detects the SSB sent by the satellite corresponding to the first GSCN, the UE determines that the current GSCN is the first GSCN.

[0276] In one possible implementation, after determining that the current GSCN is the first GSCN, the UE searches for or receives the SSB sent by the satellite in the time domain of the corresponding frequency point, that is, the UE receives the PSS and SSS sent by the satellite, and the PSS and SSS are used to determine the first PCI. The first PCI and the second GSCN (that is, the actual GSCN) of the SSB sent by the satellite conform to an odd-even correspondence.

[0277] S603A: The UE determines the first PCI based on the PSS and SSS.

[0278] For example, the UE can determine the first PCI through the PSS and SSS sequences. If the network equipment side groups the PCI into three groups, each with 336 cell IDs. The UE can obtain N from the PSS. ID(2) , N can be obtained from SSS ID(1) , further, UE can ID(1) and N ID(2) And refer to the following formula to determine the first PCI.

[0279] The first PCI uses N ID(cell) Indicates that N ID(cell) Satisfies the following formula:

[0280] N ID(cell) =3N ID(1) +N ID(2) ; Among them, N ID(1) ∈{0,1,…,335},N ID(2) ∈{0,1,2}.

[0281] S604A: The UE determines a third GSCN according to the first PCI and the first GSCN.

[0282] In one implementation, the UE determines the third GSCN according to the first PCI and the first GSCN, which may include the following:

[0283] First, the UE determines whether the first PCI and the first GSCN conform to the odd-even correspondence relationship:

[0284] If the UE determines that the first PCI and the first GSCN are in an even-odd relationship, for example, the first PCI determined by the UE based on the PSS and SSS is an odd number and the first GSCN is an even number, and therefore the first PCI and the first GSCN are in an even-odd relationship, the UE determines that the value of the third GSCN is equal to the value of the first GSCN, and subsequently the UE performs downlink synchronization and communication with the satellite based on the third GSCN.

[0285] If the UE determines that the first PCI and the first GSCN do not conform to the even-odd correspondence relationship, for example, if the first PCI determined by the UE based on the PSS and SSS is an odd number and the first GSCN is an odd number, and therefore the first PCI and the first GSCN do not conform to the even-odd correspondence relationship, the UE determines that the first GSCN is incorrect. In this case, the UE needs to redetermine the GSCN, i.e., determine the value of the third GSCN.

[0286] In a possible implementation, when the UE determines that the first GSCN is incorrect, determining the value of the third GSCN may include the following:

[0287] Since the GSCN adjacent to the first GSCN and the first PCI conform to an odd-even correspondence relationship, the UE can determine the value of the GSCN adjacent to the first GSCN as the value of the third GSCN from the GSCN range corresponding to its own working frequency band.

[0288] If there are multiple GSCNs adjacent to the first GSCN, the UE can determine the absolute difference (or interval) between the frequency points corresponding to each GSCN and the frequency points at which the UE detects the SSB, and then determine the value of the GSCN corresponding to the smallest absolute difference (or smallest interval) as the value of the third GSCN.

[0289] For example, as shown in Figure 6B, if the UE mistakenly detects GSCN = 5430 as GSCN = 5429 due to Doppler shift and local crystal oscillator drift, the UE determines the first PCI and the parity correspondence through the PSS and SSS, and knows that the correct GSCN should be an even number, therefore, the correct GSCN should be 5428 or 5430. Further, the UE determines which GSCN value, 5428 or 5430, has a frequency point closer to the frequency point where the UE detects the SSB (the bold arrow shown in Figure 6B). In Figure 6B, the frequency point where the UE detects the SSB is closer to the frequency point of GSCN = 5430 on the right, therefore, the UE determines that the third GSCN value is equal to 5430. Subsequently, the UE performs downlink synchronization and communication with the satellite based on the third GSCN value 5430.

[0290] The solution of embodiment 1 can be applicable to but not limited to scenarios where the Doppler frequency offset is less than 1 GSCN interval (that is, the Doppler frequency offset between the UE and the satellite is less than the frequency interval between a pair of adjacent GSCNs). By establishing an odd-even correspondence between PCI and GSCN, the UE is assisted in determining the correctness of the first GSCN detected by itself, and obtaining the third GSCN subsequently used for downlink synchronization and communication with the satellite.

[0291] It should be noted that in the present application, other correspondences (such as odd-odd correspondences or even-even correspondences) may be established between the PCI and the GSCN to assist the UE in determining the third GSCN for subsequent downlink synchronization and communication with the satellite. In addition, the UE may be assisted in determining the third GSCN by establishing a correspondence between other information in the network and the GSCN. Specific implementations may refer to the method of the above-mentioned embodiment 1, and this application will not describe them in detail one by one.

[0292] In implementation mode one, the UE can effectively determine the correctness of the first GSCN detected by itself based on the parity correspondence between PCI and GSCN and the first PCI provided by the satellite, and when the first GSCN is incorrect, it can also effectively determine a third GSCN that is closer to the second GSCN (for example, the numerical difference or error between the third GSCN and the second GSCN is smaller, or the interval between the third GSCN and the second GSCN is smaller) for downlink frequency synchronization with the satellite, thereby effectively improving the accuracy of downlink frequency synchronization and ensuring subsequent communication performance.

[0293] Implementation method 2: According to Table 1 in the above-mentioned related technical introduction, if the last digit (unit digit) of the GSCN changes by 1 digit, the SSB frequency difference is 50kHz or 1MHz; and if the tens digit changes by 1 digit, the SSB frequency difference is 3.7MHz or 4.6MHz. The sum of the Doppler frequency deviation caused by satellite movement and the frequency deviation caused by UE movement and local crystal oscillator drift usually does not reach the MHz level. Therefore, the change of GSCN usually involves the change of the last digit (i.e., the unit digit). Based on this, in this implementation method 2, the satellite indicates the information of the first digit and the last digit of the second GSCN to the UE (i.e., an example of the network device indicating part of the information of the second GSCN to the terminal device in an explicit manner), which is used to assist the UE in determining the GSCN and determining the third GSCN for subsequent downlink synchronization and communication. The following describes the second embodiment in detail, taking the example of a satellite with all the functions of a ground base station as an example. The second embodiment can be executed by a satellite (or a UE), or by a module (such as a processor, chip, or chip system, etc.) applied to a satellite (or a UE), or by a logical node, logical module, or software that can implement all or part of the satellite (or UE) functions. Referring to Figure 7, the specific process of the second embodiment may include the following:

[0294] S701: The satellite sends an SSB to the UE. Correspondingly, the UE may receive the SSB.

[0295] S702: The UE determines that the current GSCN is the first GSCN.

[0296] In one possible implementation, the UE determines that the current GSCN is the first GSCN, including: the UE determines the frequency band range for searching the SSB according to the corresponding working frequency band, and searches for the SSB on the corresponding synchronization grid, that is, the UE searches / detects the SSB sent by the satellite based on the GSCN range corresponding to its own working frequency band; when the UE receives / detects the PSS and SSS sent by the satellite, the corresponding first GSCN is determined as the current GSCN.

[0297] In one possible implementation, after the UE determines that the current GSCN is the first GSCN, it can search for the satellite's SSB in the time domain of the corresponding frequency point, that is, receive the PBCH sent by the satellite. The PBCH includes MIB information, which is used to indicate the first and last digits of the second GSCN sent by the satellite to send the SSB.

[0298] In a possible implementation, the satellite adds an 8-bit parameter (such as GSCN index GSCN_index) in the MIB information to indicate the binary number of the first digit of the second GSCN and the binary number of the last digit of the second GSCN.

[0299] For example, if the second GSCN is 5428, that is, the first digit of the second GSCN is 5 and the last digit (that is, the units digit) is 8, the binary representation of the first digit 5 ​​is 0101, and the binary representation of the last digit 8 is 1000. A new 8-bit parameter is added to the MIB information to indicate the binary number of the first digit and the binary number of the last digit, that is, 0101 1000, or the binary number of the last digit and the binary number of the first digit, that is, 1000 0101.

[0300] S703: The UE obtains the first digit and the last digit of the second GSCN by parsing the MIB information in the PBCH.

[0301] Since the SSB includes the PBCH, the PBCH carries the MIB information. That is, after the UE receives the PBCH, it obtains the first and last digits of the second GSCN by parsing the MIB information in the PBCH.

[0302] S704: The UE determines a third GSCN based on the information of the first digit and the last digit of the second GSCN and the first GSCN.

[0303] In one possible implementation, the UE may compare the first digit and the last digit of the first GSCN with the first digit and the last digit of the second GSCN based on the binary number of the first digit and the binary number of the last digit of the second GSCN, which may include but is not limited to the following situations:

[0304] Case 1: The first digit and the last digit of the first GSCN are equal to the first digit and the last digit of the second GSCN: The UE confirms that the first GSCN is correct, and the value of the third GSCN is equal to the value of the first GSCN.

[0305] For example, if the first GSCN is 5428, the UE determines that the first digit of the second GSCN is 5 and the last digit is 8 through the binary number of the first digit and the binary number of the last digit of the second GSCN indicated by the newly added 8-bit parameter in the MIB information. The UE then confirms that the first GSCN is correct, that is, the value of the third GSCN is equal to 5428. Subsequently, the UE performs downlink synchronization and communication with the satellite based on the third GSCN.

[0306] Case 2: The first digit of the first GSCN is equal to the first digit of the second GSCN, but the last digit of the first GSCN is not equal to the last digit of the second GSCN: the UE can modify the last digit of the first GSCN to the last digit of the second GSCN to obtain the modified first GSCN, and the value of the third GSCN is equal to the value of the modified first GSCN.

[0307] For example, if the first GSCN is 5428, the UE determines that the first digit of the second GSCN is 5 and the last digit is 9 through the binary number of the first digit and the binary number of the last digit of the second GSCN indicated by the newly added 8-bit parameter in the MIB information. The UE then modifies the last digit 8 of the first GSCN to 9, and obtains the modified value of the first GSCN as 5429, that is, the value of the third GSCN is equal to 5429. Subsequently, the UE performs downlink synchronization and communication with the satellite base station based on the third GSCN.

[0308] Case 3: The first digit of the first GSCN is not equal to the first digit of the second GSCN, or the first and last digits of the first GSCN are not equal to the first and last digits of the second GSCN:

[0309] In one possible implementation, the UE may select a target GSCN from the GSCN range corresponding to the UE's working frequency band, and determine the value of the target GSCN as the value of the third GSCN. The target GSCN should meet the following conditions:

[0310] The first digit of the target GSCN is equal to the first digit of the second GSCN, and the last digit of the target GSCN is equal to the last digit of the second GSCN, and the center frequency interval of the SSB between the target GSCN and the first GSCN is the smallest.

[0311] For example, if the first GSCN is 3000, the UE determines that the first digit of the second GSCN is 2 and the last digit is 9 through the binary number of the first digit and the binary number of the last digit of the second GSCN indicated by the newly added 8-bit parameter in the MIB information. The UE then confirms that the first GSCN is incorrect. Further, the UE selects a target GSCN 2999 from the candidate GSCN range corresponding to its own working frequency band. The first digit of the target GSCN is 2 and the last digit is 9, and the center frequency interval of the SSB between the target GSCN and the first GSCN 3000 is the smallest. The UE determines that the value of the third GSCN is equal to 2999.

[0312] In the present application, in order to reduce the overhead generated by the MIB information indication, in a possible implementation method, the satellite side can also add a GSCN_index with fewer bits in the MIB information. The GSCN_index can be expressed as a numerical value (or a symbol or information, etc.), and the numerical value (or symbol or information, etc.) can be obtained based on the first digit and the last digit of the second GSCN.

[0313] For example, if the second GSCN is 5428, that is, the first digit of the second GSCN is 5 and the last digit (i.e., the units digit) is 8, the first digit 5 ​​and the last digit 8 of the second GSCN form the value 58, and the binary representation of 58 is 111010. The satellite side can add a 6-bit GSCN_index in the MIB information, represented as 111010.

[0314] In the embodiment of the present application, the combination mechanism of the first digit and the last digit of the second GSCN may be pre-set and known to the satellite side and the UE side, or may be pre-negotiated and agreed upon by the satellite side and the UE side.

[0315] In addition, a mapping relationship may be established between the first and last digits of the second GSCN and the GSCN_index, where the content represented by the GSCN_index may be a value, a symbol, or information, and occupies fewer bits in the MIB information. The aforementioned mapping relationship may be pre-set and known to the satellite and the UE, or may be pre-negotiated or agreed upon between the satellite and the UE.

[0316] It should be noted that in the present application, MIB information can also be used to indicate information about other digits of the second GSCN, such as information indicating the last two digits 2 and 8 of the second GSCN if the second GSCN is 5428, or information indicating the middle digit 4 and the last digit 8, etc. MIB information can also be used to indicate fewer or more digits of the second GSCN. For example, when the first digits of the first GSCN and the second GSCN are equal, the satellite can indicate the last digit of the second GSCN to the UE through MIB information, or the satellite can indicate the three digits of the second GSCN to the UE through MIB information. The specific indication method can be implemented with reference to the above-mentioned method of indicating the first and last digits of the second GSCN by MIB information. As long as the UE can effectively and accurately determine the accuracy of the first GSCN based on at least one value of the second GSCN indicated by the MIB information (i.e., partial information of the second GSCN), and obtain the value of the third GSCN, it is sufficient. As can be seen from the above, the satellite can indicate partial information of the second GSCN to the UE through MIB information, which can effectively reduce the overhead generated by the indication.

[0317] In implementation mode two, the satellite indicates the information of the first digit and the last digit of the second GSCN to the UE in a displayed manner (that is, an example of the network device indicating part of the information of the second GSCN to the terminal device in an explicit manner). In this way, the UE can effectively determine the correctness of the first GSCN detected by itself based on the information of the first digit and the last digit of the second GSCN. In the case that the first GSCN is incorrect, the UE can also determine a third GSCN that is closer to the second GSCN (for example, the numerical difference or error between the third GSCN and the second GSCN is smaller, or the interval between the third GSCN and the second GSCN is smaller) for subsequent downlink synchronization and communication with the satellite.

[0318] In addition, compared with the first embodiment, the second embodiment can not only calibrate adjacent odd and even GSCNs, but also calibrate ten adjacent GSCNs. Moreover, the indication method of the second embodiment is more accurate and can more effectively avoid the UE from misdetecting the GSCN, thereby effectively ensuring the accuracy of the subsequent downlink synchronization between the UE and the satellite, and thus ensuring the subsequent communication performance.

[0319] Implementation Method 3: According to Table 1 in the above-mentioned related art introduction, the GSCN is jointly determined by the two parameters N and M. If the value of N changes by 1 bit, the SSB frequency changes by 1.2 MHz. If the value of M changes by 1 bit, the SSB frequency changes by 100 kHz or 1 MHz (the value of M changes from 5 to 1). Due to the Doppler frequency offset and the frequency offset caused by the UE, the deviation of the SSB frequency usually does not reach the order of MHz. Based on this, in Implementation Method 3, to reduce the number of additional bits in the MIB information and reduce the indication overhead, the satellite can indicate the M value corresponding to the second GSCN to the UE (i.e., an example of partial information of the second GSCN) to assist the UE in determining the accuracy of the first GSCN detected by itself and determining the value of the third GSCN. Implementation Method 3 is described in detail below using a satellite with all the functions of a ground base station as an example. Implementation Method 3 can be executed by a satellite (which can also be a UE), or by a module (e.g., a processor, chip, or chip system, etc.) applied to the satellite (which can also be a UE), or by a logical node, logical module, or software that can implement all or part of the functions of the satellite (which can also be a UE). 8 , the specific process of the third embodiment may include the following:

[0320] S801: The satellite sends an SSB to the UE, and the UE receives the SSB accordingly.

[0321] S802: The UE determines that the current GSCN is the first GSCN.

[0322] S801 and S802 may be implemented with reference to S701 and S702 in the above-mentioned second embodiment, but differ from the second embodiment in that the MIB information in the PBCH is used to indicate the M value corresponding to the second GSCN.

[0323] S803: The UE obtains the M value corresponding to the second GSCN by parsing the MIB information in the PBCH.

[0324] Since the SSB includes the PBCH, the PBCH carries the MIB information. That is, after the UE receives the PBCH, it parses the MIB information therein to obtain the M value corresponding to the second GSCN.

[0325] S804: The UE determines a third GSCN according to the M value corresponding to the second GSCN and the first GSCN.

[0326] In one possible implementation, the UE determines the N and M values ​​corresponding to the first GSCN, and then compares the M value corresponding to the first GSCN with the M value corresponding to the second GSCN. If they are the same, the first GSCN is confirmed to be correct, the value of the third GSCN is equal to the value of the first GSCN, and the UE can subsequently perform downlink synchronization and communication with the satellite based on the third GSCN. If they are not the same, the UE modifies the M value corresponding to the first GSCN to the M value corresponding to the second GSCN, and then recalculates the value of the first GSCN based on the modified M value and the N value corresponding to the first GSCN.

[0327] For example, the UE determines the value of the third GSCN according to the M value corresponding to the second GSCN and the first GSCN, which may include the following steps:

[0328] Step 1: The first GSCN detected by the UE itself is represented as GSCN UE , the N and M values ​​corresponding to the first GSCN are recorded as N UE , M UE The UE can calculate the N value and M value corresponding to the first GSCN according to the following formula. UE =round(GSCN UE / 3); M UE =K1×5+K2×3+K3×1;

[0329] If we calculate (GSCN UE / 3-N UE )>0, then K1=1, otherwise K1=0; if (GSCN UE / 3-N UE )=0, then K2=1, otherwise K2=0; if (GSCN UE / 3-N UE )<0, then K3=1, otherwise K3=0.

[0330] Step 2: The satellite adds a 2-bit parameter in the MIB information to indicate the M value corresponding to the second GSCN, which is expressed as M index UE will M index With M UE Perform comparison. If M index With M UE If they are equal, the value of the third GSCN is equal to GSCN UE (i.e. the first GSCN).

[0331] If M index With M UE If they are not equal, the UE will UE Modified to M index , further, the UE recalculates the value of the first GSCN, expressed as GSCN′ UE , then the value of the third GSCN is equal to GSCN′ UE Among them, GSCN′ UE The calculation of GSCN′ is in accordance with the following formula: UE =3×N UE +(M index -3) / 2;

[0332] In the above, "round()" is a function that rounds the value, " / " is a division sign, and "×" is a multiplication sign.

[0333] Through the above two steps, the UE can UE M corresponding to the second GSCN indicated by the satellite index The correct third GSCN value is jointly determined, and the UE can subsequently perform downlink synchronization and communication with the satellite based on the third GSCN.

[0334] In the third embodiment, the GSCN change caused by frequency offset only affects the M value corresponding to the GSCN. The satellite can display the M value corresponding to the second GSCN (i.e., the actual GSCN) to the UE (i.e., an example of partial information of the second GSCN). In this way, the UE can compare the M value corresponding to the second GSCN with the M value corresponding to the first GSCN detected by itself to see if they are equal. If they are equal, the UE can confirm that the value of the third GSCN is equal to the value of the first GSCN. If they are not equal, the UE can also effectively determine the third GSCN that is closer to the second GSCN (e.g., the numerical difference or error between the third GSCN and the second GSCN is smaller, or the interval between the third GSCN and the second GSCN is smaller) for subsequent downlink synchronization with the satellite, thereby ensuring the accuracy of downlink synchronization and improving subsequent communication quality. In addition, compared to the second embodiment, the number of bits added by the satellite in the MIB information in the third embodiment is smaller, resulting in less signaling overhead.

[0335] In the present application, in order to ensure that the UE can accurately know the second GSCN of the actual satellite sending SSB, the satellite may also indicate all the information of the second GSCN to the UE through MIB information, such as the total number of bits of the second GSCN (ie, the value of the second GSCN), or the N value and M value corresponding to the second GSCN.

[0336] In summary, in implementation modes one to three, the UE detects the SSB sent by the network device (such as a satellite) according to the existing synchronization grid, and determines the third GSCN for subsequent downlink synchronization. In order to improve the accuracy of the UE's determination of the third GSCN, the network device (such as a satellite) assists the UE in determining the correctness of the first GSCN detected by itself and determines the third GSCN by indicating part or all of the information of the second GSCN to the UE. However, these implementation modes will increase the complexity of UE-side processing to a certain extent and increase the signaling overhead of the system. To address this problem, the embodiment of the present application also provides a solution as described in Figure 5B, that is, by sparsely detecting the GSCN to be detected (that is, expanding / increasing the interval between two adjacent GSCNs to be detected by the UE) to reduce the probability of the UE's own misdetection of the GSCN, thereby improving the accuracy of downlink synchronization and the subsequent communication quality.

[0337] The solution described in FIG. 5B will be introduced below through several specific implementations.

[0338] Implementation 4: Based on the calculation formula for the SSB frequency position shown in Table 1 in the above-mentioned related art introduction, it can be seen that the step value of M affects the frequency interval between two adjacent GSCNs detected by the UE. Therefore, in Implementation 4, the GSCN can be sparsely distributed by modifying the step value of M corresponding to the GSCN.

[0339] Table 1 above shows the SS of all frequency ranges in the current technology. REF According to Table 1 above, the center frequency position (frequency point) of SSB is SS. REF The formula satisfied is: SS REF =N×1200kHz+M×50kHz; wherein, N∈[1:2499], that is, the value of N is any integer value from 1 to 2499 (including 1 or 2499), and M∈{1,3,5}, that is, the value of M is any integer value from 1, 3, 5.

[0340] According to the above SS REF The calculation formula shows that the step value of M in the current technology (i.e., the first step value of M in the solution described in Figure 5B above) is 50, with the unit being kilohertz (kHz). If M is 1, 3, or 5, then, for the same N value, the frequency spacing Δf (or the absolute frequency difference Δf) between two adjacent GSCNs to be detected satisfies the following formula: Δf = spacing (or absolute frequency difference) between two adjacent GSCNs to be detected * 50 kHz = 2 * 50 kHz = 100 kHz.

[0341] Since the frequency error caused by Doppler frequency offset and local crystal oscillator is limited, if the grid spacing between two adjacent GSCNs in the GSCN range that the UE needs to detect (that is, the frequency interval between two adjacent GSCNs to be detected) is expanded, the probability of subsequent UE misdetecting GSCNs due to frequency offset can be effectively reduced.

[0342] Based on the above, the UE needs to traverse each GSCN within the GSCN range corresponding to its own working frequency band to search / detect the SSB situation. In this fourth embodiment, the frequency interval between two adjacent GSCNs can be increased by increasing the step value of M, thereby increasing the frequency interval between two adjacent GSCNs that the UE needs to detect.

[0343] In a possible implementation, the second step value of M is set to an integer greater than 50, and its unit is kHz.

[0344] In the embodiment of the present application, when setting the second step value of M, the following conditions need to be met:

[0345] (1) When setting the second step value of M, it should be ensured that there is no overlap or intersection between adjacent GSCN sets. Adjacent GSCN sets can refer to GSCN sets corresponding to adjacent N values, that is, all GSCNs in the same GSCN set have the same N value but different M values.

[0346] (2) When setting the second step value of M, it is necessary to ensure that M has at least one feasible value.

[0347] The feasible value of M means that the value of M can ensure that the interval (or absolute difference) between the SSB center frequency position of each GSCN and the center frequency position of the PDSCH / PDCCH is an integer multiple of 15 kHz.

[0348] (3) By setting the second step value of M, when the interval between adjacent GSCNs is greater than 100 kHz, the detection performance is not weaker than that of the prior art. For example, when the interval between adjacent GSCNs is greater than 100 kHz, the detection performance is not weaker than that when the interval between adjacent GSCNs is 100 kHz.

[0349] For example, as shown in Table 4 below, setting the second step value of M to 100kHz, it can be seen that M∈{1,3,5} can ensure that the interval between the SSB center frequency and the channel center frequency (that is, the interval between the SSB center frequency position of the GSCN and the center frequency position of the full bandwidth of the channel) is an integer multiple of 15kHz and complete (that is, when M is 1, 3, 5, it can completely cover all cases where the aforementioned interval is an integer multiple of 15kHz). At this time, the frequency interval between two adjacent GSCNs is 200kHz.

[0350] Table 4

[0351] The content or information shown in Table 4 above is only an example. In actual applications, Table 4 may contain more or less content (or information).

[0352] For example, the following Table 5 shows the SS frequency range of 0 to 3000 MHz used in the embodiment of the present application. REF and GSCN parameters. The synchronization grid and the corresponding SSB do not cover all possible RF channel bandwidths and positions on the enhanced synchronization grid. See Table 5 below. REF From the calculation formula, it can be seen that when the second step value of M is set to 100 kHz, when the N value is the same, the frequency interval Δf′ (or the absolute frequency difference Δf′) between two adjacent GSCNs to be detected is 200 kHz.

[0353] Table 5

[0354] The content or information shown in Table 5 above is only an example. In actual applications, Table 5 may contain more or less content (or information).

[0355] For example, taking the GSCN search range of 2999 to 3007 as an example, within the GSCN search range, FIG9 (1) shows a schematic diagram of the first step value of M of 50kHz, and FIG9 (2) shows a schematic diagram of the second step value of M of 100kHz. When the UE needs to traverse and detect each GSCN value within the GSCN range corresponding to its own working frequency band to search for SSB, the frequency interval between two adjacent GSCNs to be detected in each GSCN set shown in FIG9 (2) is larger than that in each GSCN set shown in FIG9 (1).

[0356] By adjusting / modifying the step value of M as described above, the frequency interval between two adjacent GSCNs that the UE needs to detect can be effectively expanded, that is, the purpose of thinning the GSCNs to be detected (the GSCNs to be detected are GSCNs within the GSCN range corresponding to the UE's operating frequency band) is achieved. Therefore, during the initial access phase, when the UE searches or detects the SSB sent by a network device (e.g., a satellite) based on the thinned GSCNs to be detected to determine the first GSCN, the probability of the UE misdetecting the GSCN can be effectively reduced.

[0357] In the present application, the method described in embodiment 4 can be implemented or executed independently, and is used for the UE to detect the GSCN of the SSB sent by the network device, without the network device sending additional new parameters to indicate the information associated with the second GSCN (i.e., the actual GSCN), which can reduce the signaling overhead. This embodiment 4 can also be applied to any one of the above-mentioned embodiments 1 to 3, and is used for the UE to determine / detect the current GSCN itself; further, the UE corrects the first GSCN determined / detected by itself in combination with the information associated with the second GSCN (i.e., the actual GSCN) shown in any one of embodiments 1 to 3, and obtains a third GSCN that is closer to the second GSCN (for example, the numerical difference or error between the third GSCN and the second GSCN is smaller, or the interval between the third GSCN and the second GSCN is smaller). Subsequently, the UE performs downlink synchronization and communication with the network device based on the finally determined third GSCN, which can greatly improve the accuracy of downlink synchronization and the performance of communication.

[0358] Implementation method five: Compared with the method described in implementation method four, in implementation method five, sparse GSCNs to be detected are achieved by modifying the step size of GSCNs, that is, increasing the interval between two adjacent GSCNs to be detected by the UE.

[0359] In the above-mentioned related art introduction, Table 3 shows the synchronization raster for each frequency band in FR1. The distance or interval between two adjacent GSCNs to be detected is represented by the step size. As shown in Table 3, the step size value of the GSCN in the prior art is set to 1. Therefore, referring to Table 3, in this fifth embodiment, the step size value of the GSCN is increased to increase the distance or interval between two adjacent GSCNs to be detected by the UE.

[0360] In one possible implementation, under sub3G, since the GSCN value is jointly determined by the two parameters N and M, M∈{1,3,5}, while ensuring that the range of M remains unchanged, the step size is set to an integer greater than 1. However, the step size cannot be an integer multiple of 3. This is to ensure that the constraints of M remain unchanged, that is, that M can be a value within 1, 3, and 5.

[0361] For example, taking the step size value as 4 as an example, as shown in Table 6, which is the synchronization grid of each frequency band of FR1, the distance or interval between two adjacent GSCNs to be detected is represented by the step size, and the step size value is 4.

[0362] Table 6

[0363] Table 6 above is only an example. In actual applications, the step size may also take other integer values. However, the step size value must be greater than 1 and cannot be an integer multiple of 3.

[0364] For example, FIG10 shows the changes in the GSCN to be detected on the UE side when the step size is changed to 4. The GSCN range shown in FIG10 is based on the example of GSCN from 2999 to 3013. Referring to FIG10 (1), it can be seen that when the step size is set to 1, within the GSCN range, when the UE detects the SSB sent by the network device (such as a satellite), it needs to traverse and search all GSCN values ​​from 2999 to 3013 until the optimal SSB is detected. The frequency interval between each adjacent GSCN to be detected is 100kHz. Referring to FIG10 (2), when the step size is set to 4, the GSCNs that the UE needs to search are 2999, 3003, 3007, and 3011. Compared with the step size of 1, the interval between the adjacent GSCNs to be detected is significantly increased. Therefore, the probability of the UE misdetecting the GSCN in the future will be greatly reduced.

[0365] In the fifth embodiment, by adjusting / modifying the step size of the GSCN as described above, the interval between the two adjacent GSCNs to be detected is expanded, thereby achieving the purpose of sparsely sparse GSCNs to be detected. The method described in the fifth embodiment can be adjusted for the GSCN range corresponding to the working frequency band where the UE is located. During the initial access phase, the UE can detect the SSB sent by the network device (such as a satellite) according to the increased step size value, that is, when detecting the SSB sent by the network device to determine the first GSCN in the sparsely sparse GSCN range to be detected (that is, the example of the first GSCN area described in Figure 5B above), the probability of the UE misdetecting the GSCN can be effectively reduced. In addition, compared with the fourth embodiment, the fifth embodiment not only achieves the sparseness of the GSCNs to be detected by the UE, but also reduces the number of GSCNs that the UE needs to detect, thereby reducing the delay of the UE's initial access.

[0366] In the present application, the method described in embodiment 5 can be implemented or executed independently, and is used for the UE to determine / detect the GSCN of the SSB sent by the network device, without the network device sending additional new parameters to indicate the information associated with the second GSCN (i.e., the actual GSCN), which can reduce the signaling overhead. This embodiment 5 can also be applied to any one of the above-mentioned embodiments 1 to 3, and is used for the UE to determine / detect the current GSCN by itself; further, the UE corrects the first GSCN determined / detected by itself in combination with the information associated with the second GSCN (i.e., the actual GSCN) shown in any one of embodiments 1 to 3, and obtains a third GSCN that is closer to the second GSCN (for example, the numerical difference or error between the third GSCN and the second GSCN is smaller, or the interval between the third GSCN and the second GSCN is smaller). Subsequently, the UE performs downlink synchronization and communication with the network device based on the finally determined third GSCN, which can greatly improve the accuracy of downlink synchronization and the performance of communication.

[0367] Regarding the above-mentioned embodiments 1 to 5, it should be noted that:

[0368] (1) The above-mentioned embodiments 1 to 5 can be implemented separately or in combination, without any specific limitation. For example, the method described in embodiment 4 or embodiment 5 can be implemented in combination with any one of the above-mentioned embodiments 1 to 3.

[0369] (2) The above description focuses on the differences between Implementation Modes 1 to 3, and the differences between Implementation Modes 4 and 5. Except for the differences, Implementation Modes 1 to 3 can refer to each other, and Implementation Modes 4 and 5 can refer to each other.

[0370] (3) The step numbers in the flowcharts described in Implementation Methods 1 to 5 are merely examples of the execution process and do not limit the order in which the steps are executed. There are no sequential dependencies between the steps in the various implementations of this application, and there is no strict execution order. Furthermore, not all of the steps shown in the flowcharts are mandatory steps, and steps may be added or deleted based on actual needs.

[0371] In the embodiments provided in the present application, the methods provided in the embodiments of the present application are introduced from the perspective of interaction between various devices. In order to implement the various functions in the methods provided in the embodiments or implementations of the present application, the terminal device or network device may include a hardware structure and / or a software module to implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a function of the above functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.

[0372] The division of modules in the embodiments of the present application is illustrative and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments or implementations of the present application may be integrated into a single processor, or may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0373] Similar to the above concept, as shown in FIG11 , an embodiment of the present application further provides a communication device 1100 for implementing the functions of the terminal device or network device in the above method. For example, the communication device 1100 may be a software module or a chip system. In the embodiment of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices. The communication device 1100 may include: a communication unit 1101 and a processing unit 1102.

[0374] In the embodiments of the present application, the communication unit 1101 may also be referred to as a transceiver unit, and may include a sending unit and / or a receiving unit, each configured to execute the steps of sending and receiving by the terminal device or network device in the above method embodiments. The processing unit 1102 may be configured to read instructions and / or data from the storage module, so that the communication device 1100 implements the above method embodiments or implementation methods.

[0375] Optionally, the communication device 1100 may further include a storage unit 1103 , which is equivalent to a storage module and may be used to store instructions and / or data.

[0376] The communication device provided in the embodiments of the present application is described in detail below with reference to Figures 11 and 12. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, the contents not described in detail can be implemented with reference to the methods shown in Figures 5A and 5B above, and for the sake of brevity, they are not repeated here.

[0377] Communication unit 1101 may also be referred to as a transceiver, transceiver, or transceiver device. A processing unit may also be referred to as a processor, processing board, processing module, or processing device. Alternatively, the device in communication unit 1101 that implements the receiving function may be considered a receiving unit, and the device in communication unit 1101 that implements the transmitting function may be considered a transmitting unit. That is, communication unit 1101 includes both a receiving unit and a transmitting unit. A communication unit may also be referred to as a transceiver, transceiver, or transceiver circuit. A receiving unit may also be referred to as a receiver, receiver, or receiving circuit. A transmitting unit may also be referred to as a transmitter, transmitter, or transmitting circuit.

[0378] When the communication device 1100 executes the terminal device in the process shown in Figure 5A of the above embodiment: the processing unit 1102 is used to determine that the current global synchronization channel number GSCN is the first GSCN; the communication unit 1101 is used to receive first information from the network device, the first information is used to indicate information associated with the second GSCN, and the second GSCN is the GSCN for sending the synchronization signal block SSB by the network device; the processing unit 1102 is also used to determine the third GSCN based on the first GSCN and the first information.

[0379] When the communication device 1100 executes the network device in the process shown in Figure 5A of the above embodiment: the processing unit 1102 is used to generate first information, where the first information is used to indicate information associated with a second global synchronization channel number GSCN, and the second GSCN is the GSCN for sending SSB by the network device; the communication unit 1101 is used to send the first information.

[0380] When the communication device 1100 executes the terminal device in the process shown in Figure 5B of the above embodiment: the processing unit 1102 is used to determine the first GSCN area; the range of the first GSCN area is the same as the range of the second GSCN area, the second GSCN area is determined by the working frequency band corresponding to the terminal device, the first GSCN area and the second GSCN area respectively include at least two GSCNs, and the interval between the two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between the two adjacent GSCNs to be detected in the second GSCN area; the communication unit 1101 is used to receive the SSB from the network device based on the first GSCN area, and determine the first GSCN corresponding to the received SSB as the current global synchronization channel number GSCN.

[0381] When the communication device 1100 executes the network device in the process shown in Figure 5B of the above embodiment: the processing unit 1102 is used to determine the second GSCN from the first GSCN area; the range of the first GSCN area is the same as the range of the second GSCN area, the second GSCN area is determined by the working frequency band corresponding to the terminal device, the first GSCN area and the second GSCN area respectively include at least two GSCNs, and the frequency interval between two adjacent GSCNs in the first GSCN area is greater than the frequency interval between two adjacent GSCNs in the second GSCN area; the communication unit 1101 is used to send SSB based on the second GSCN.

[0382] The above is just an example. The communication unit 1101 and the processing unit 1102 can also perform other functions. For more detailed description, please refer to the relevant description in the method embodiment shown in Figures 5A and 5B, which will not be repeated here.

[0383] Figure 12 illustrates another communication device 1200 provided in an embodiment of the present application. The communication device shown in Figure 12 may be a hardware circuit implementation of the communication device shown in Figure 11. This communication device 1200 may be used in the flowcharts shown above to perform the functions of the terminal device or network device in the above-described method embodiments. For ease of illustration, Figure 12 only illustrates the main components of the communication device.

[0384] As shown in Figure 12, communication device 1200 includes a communication interface 1201 and a processor 1202. Communication interface 1201 and processor 1202 are coupled to each other. It is understood that communication interface 1201 can be a transceiver or input / output interface, or an interface circuit such as a transceiver circuit. Optionally, communication device 1200 can also include a memory 1203 for storing instructions executed by processor 1202, input data required by processor 1202 to execute instructions, or data generated by processor 1202 after executing instructions.

[0385] When the communication device 1200 is used to implement the method shown in FIG. 5A or FIG. 5B , the communication interface 1201 is used to implement the functions of the communication unit 1101 , and the processor 1202 is used to implement the functions of the processing unit 1102 .

[0386] The specific connection medium between the communication interface 1201, the processor 1202, and the memory 1203 is not limited in the embodiments of the present application. In Figure 12, the embodiment of the present application shows that the memory 1203, the processor 1202, and the communication interface 1201 are connected via a communication bus 1204. The communication bus 1204 is represented by a bold line in Figure 12. The connection method between other components is only for schematic illustration and is not intended to be limiting. The communication bus 1204 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one bold line is used in Figure 12, but this does not mean that there is only one bus or one type of bus.

[0387] When the communication device is a chip, FIG13 shows a simplified schematic diagram of the chip structure, wherein the chip 1300 includes an interface circuit 1301 and one or more processors 1302. Optionally, the chip 1300 may further include a bus.

[0388] The processor 1302 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above-mentioned method for determining service node information can be completed by hardware integrated logic circuits or software instructions in the processor 1302. The above-mentioned processor 1302 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods and steps disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0389] The interface circuit 1301 can be used to send or receive data, instructions or information. The processor 1302 can use the data, instructions or other information received by the interface circuit 1301 to process it, and can send the processing completion information through the interface circuit 1301.

[0390] Optionally, the chip further includes a memory 1303, which may include a read-only memory and a random access memory, and provides operating instructions and data to the processor. A portion of the memory 1303 may also include a non-volatile random access memory (NVRAM).

[0391] Optionally, the memory stores an executable software module or a data structure, and the processor can perform corresponding operations by calling an operation instruction stored in the memory (the operation instruction may be stored in an operating system).

[0392] Optionally, the chip can be used in a terminal device or network device involved in the embodiments of the present application. Optionally, the interface circuit 1301 can be used to output the execution result of the processor 1302. Regarding the communication method provided in one or more embodiments of the present application, reference can be made to the aforementioned embodiments or implementation methods, and no further details will be given here.

[0393] It should be noted that the corresponding functions of the interface circuit 1301 and the processor 1302 can be implemented through hardware design, software design, or a combination of hardware and software, and there is no limitation here.

[0394] An embodiment of the present application also provides a computer-readable storage medium on which computer instructions for implementing the method executed by a terminal device or a network device in the above method embodiment are stored.

[0395] For example, when the computer program is executed by a computer, the computer can implement the method performed by the terminal device or the network device in the above method embodiment.

[0396] An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to implement the method executed by the terminal device or the network device in the above method embodiment.

[0397] An embodiment of the present application also provides a chip, including a processor, for calling the computer program or computer instructions stored in the memory so that the processor executes the communication method of the implementation method shown in Figures 5A and 5B, Figure 6A, Figure 7 and Figure 8 above.

[0398] In one possible implementation, the input of the chip corresponds to the receiving operation in the implementation shown in Figures 5A and 5B, Figure 6A, Figure 7 and Figure 8 above, and the output of the chip corresponds to the sending operation in the implementation shown in Figures 5A and 5B, Figure 6A, Figure 7 and Figure 8 above.

[0399] Optionally, the processor is coupled to the memory via an interface.

[0400] Optionally, the chip further includes a memory in which computer programs or computer instructions are stored.

[0401] The processor mentioned in any of the above may be a general-purpose central processing unit, a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of a program of a communication method in the implementation manner shown in Figures 5A and 5B, Figure 6A, Figure 7, and Figure 8. The memory mentioned in any of the above may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM), etc.

[0402] It should be noted that, for the sake of convenience and brevity of description, the explanation of the relevant contents and beneficial effects of any of the communication devices provided above may refer to the embodiments of the corresponding communication methods provided above, and will not be repeated here.

[0403] In the present application, the communication devices may further include a hardware layer, an operating system layer running on top of the hardware layer, and an application layer running on the operating system layer. The hardware layer may include hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also known as main memory). The operating system of the operating system layer may be any one or more computer operating systems that implement business processing through processes, such as the Linux operating system, Unix operating system, Android operating system, iOS operating system, or Windows operating system. The application layer may include applications such as browsers, address books, word processing software, and instant messaging software.

[0404] The division of modules in the embodiments of the present application is illustrative and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the present application may be integrated into a single processor, or may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0405] Through the description of the above embodiments, it will be clear to those skilled in the art that the embodiments of the present application can be implemented in hardware, firmware, or a combination thereof. When software is used for implementation, the above functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein the communication media include any medium that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that a computer can access. For example, but not limited to: a computer-readable medium may include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store a desired program code in the form of an instruction or data structure and can be accessed by a computer. In addition, any connection can be appropriately a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used in the embodiments of the present application, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically and discs use lasers to reproduce data optically. Combinations of the above should also be included within the scope of protection of computer-readable media.

[0406] In short, the above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made based on the disclosure of the present application should be included in the scope of protection of the present application.

Claims

1. A communication method, characterized in that: The method is applied to a terminal device or a chip of the terminal device, and includes: Determine the current global synchronization channel number GSCN as the first GSCN; receiving first information from a network device, where the first information is used to indicate information associated with a second GSCN, where the second GSCN is a GSCN for sending a synchronization signal block SSB by the network device; A third GSCN is determined according to the first GSCN and the first information.

2. The method according to claim 1, characterized in that There is a correspondence between GSCN and physical cell identifier PCI; The first information is used to determine a first physical cell identifier PCI; The determining, according to the first GSCN and the first information, a third GSCN includes: If the first GSCN and the first PCI satisfy the corresponding relationship, the value of the third GSCN is equal to the value of the first GSCN; If the first GSCN and the first PCI do not conform to the correspondence, a target GSCN that conforms to the correspondence with the first PCI is determined from at least one candidate GSCN, and the distance between the center frequency position of the SSB corresponding to the target GSCN and the center frequency position of the SSB detected by the terminal device for the network device is the smallest, and the value of the third GSCN is equal to the value of the target GSCN; wherein the at least one candidate GSCN is determined by the working frequency band corresponding to the terminal device.

3. The method according to claim 1, characterized in that The first information is used to indicate part or all of the information of the second GSCN.

4. The method according to claim 3, characterized in that when the partial information of the second GSCN is at least one digit of the second GSCN; The determining, according to the first GSCN and the first information, a third GSCN includes: If the value of at least one digit in the same position in the first GSCN is consistent with the value of at least one digit in the second GSCN, the value of the third GSCN is equal to the value of the first GSCN; If the value of at least one digit in the same position in the first GSCN is inconsistent with the value of at least one digit in the second GSCN, the value of the first GSCN is adjusted according to at least one digit of the second GSCN to obtain an adjusted first GSCN, and the value of the third GSCN is equal to the value of the adjusted first GSCN.

5. The method according to claim 3, characterized in that Part of the information of the second GSCN is the value of the first parameter M corresponding to the second GSCN; The determining, according to the first GSCN and the first information, a third GSCN includes: Determine the value of the first parameter M and the value of the second parameter N corresponding to the first GSCN; the first parameter M and the second parameter N are used to represent the center frequency position of the SSB corresponding to the GSCN; If the value of the first parameter M corresponding to the first GSCN is equal to the value of the first parameter M corresponding to the second GSCN, the value of the third GSCN is equal to the value of the first GSCN; If the value of the first parameter M corresponding to the first GSCN is not equal to the value of the first parameter M corresponding to the second GSCN, updating the value of the first parameter M corresponding to the first GSCN to the value of the first parameter M corresponding to the second GSCN, to obtain an updated value of the first parameter M corresponding to the first GSCN; According to the updated value of the first parameter M corresponding to the first GSCN and the value of the second parameter N corresponding to the first GSCN, the updated value of the first GSCN is determined, and the value of the third GSCN is equal to the updated value of the first GSCN.

6. The method according to claim 2, characterized in that The first information is a primary synchronization signal PSS sequence and a secondary synchronization signal SSS sequence in the SSB of the network device, and the primary synchronization signal PSS sequence and the secondary synchronization signal SSS sequence are used to determine the first PCI.

7. The method according to any one of claims 3 to 5, characterized in that The first information is carried in a master system information block (MIB) of the SSB of the network device.

8. A communication method, characterized in that: The method is applied to a terminal device or a chip of the terminal device, and includes: Determine a first GSCN area; the range of the first GSCN area is the same as the range of the second GSCN area, the second GSCN area is determined by the working frequency band corresponding to the terminal device, the first GSCN area and the second GSCN area each include at least two GSCNs, and the interval between the two adjacent GSCNs to be detected in the first GSCN area is greater than the interval between the two adjacent GSCNs to be detected in the second GSCN area; Based on the first GSCN area receiving the SSB from the network device, the first GSCN corresponding to the received SSB is determined as the current global synchronization channel number GSCN.

9. The method according to claim 8, characterized in that The center frequency position of the SSB corresponding to the GSCN in the second GSCN area is represented by the following information: A first parameter M, a first step value of the first parameter M, a second parameter N, a step value of the second parameter N; The interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the second GSCN area is associated with the first step value and / or the step value of the second parameter N, and N and M are positive integers.

10. The method according to claim 8 or 9, characterized in that The center frequency position of the SSB corresponding to the GSCN in the first GSCN area is represented by the following information: a first parameter M, a second step value of the first parameter M, a second parameter N, and a step value of the second parameter N; In which, the interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the first GSCN area is associated with the second step value and / or the step value of the second parameter N, the second step value is greater than the first step value of the first parameter M, and N and M are positive integers.

11. The method according to claim 10, characterized in that The interval between the center frequency position of the SSB corresponding to the GSCN in the first GSCN area and the full-bandwidth downlink center frequency position of the transmission channel is an integer multiple of 15kHz.

12. The method according to claim 8, characterized in that The second GSCN area corresponds to the first step distance, and the first step distance is used to represent the absolute difference between two adjacent GSCNs to be detected in the second GSCN area.

13. The method according to claim 8 or 12, characterized in that The first GSCN area corresponds to a second step distance, and the second step distance is used to characterize the absolute difference between two adjacent GSCNs to be detected in the first GSCN area. The value of the second step distance is greater than the value of the first step distance corresponding to the second GSCN area.

14. A communication method, characterized in that: The method is applied to a network device or a chip of the network device, and includes: Generate first information, where the first information is used to indicate information associated with a second global synchronization channel number GSCN, where the second GSCN is a GSCN for sending an SSB by the network device; The first information is sent.

15. The method according to claim 14, characterized in that There is a corresponding relationship between the GSCN and the physical cell identifier PCI, and the first information is used to determine the first physical cell identifier PCI.

16. The method according to claim 14, characterized in that The first information is used to indicate part or all of the information of the second GSCN.

17. The method according to claim 16, characterized in that Part of the information of the second GSCN is any one of the following: At least one digit of the second GSCN and the value of the first parameter M corresponding to the second GSCN.

18. The method according to claim 15, characterized in that The first information is a primary synchronization signal PSS sequence and a secondary synchronization signal SSS sequence in the SSB of the network device, and the primary synchronization signal PSS sequence and the secondary synchronization signal SSS sequence are used to determine the first PCI.

19. The method according to claim 16 or 17, characterized in that The first information is carried in a master system information block (MIB) of the SSB of the network device.

20. A communication method, characterized in that: The method is applied to a network device or a chip of the network device, and includes: Determine a second GSCN from the first GSCN area; the range of the first GSCN area is the same as the range of the second GSCN area, the second GSCN area is determined by the working frequency band corresponding to the terminal device, the first GSCN area and the second GSCN area each include at least two GSCNs, and the frequency interval between two adjacent GSCNs in the first GSCN area is greater than the frequency interval between two adjacent GSCNs in the second GSCN area; Based on the second GSCN, send SSB.

21. The method according to claim 20, characterized in that The center frequency position of the SSB corresponding to the GSCN in the second GSCN area is represented by the following information: A first parameter M, a first step value of the first parameter M, a second parameter N, a step value of the second parameter N; The interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the second GSCN area is associated with the first step value and / or the step value of the second parameter N, and N and M are positive integers.

22. The method according to claim 20 or 21, characterized in that The center frequency position of the SSB corresponding to the GSCN in the first GSCN area is represented by the following information: a first parameter M, a second step value of the first parameter M, a second parameter N, and a step value of the second parameter N; In which, the interval between the center frequency positions of the SSBs corresponding to two adjacent GSCNs in the first GSCN area is associated with the second step value and / or the step value of the second parameter N, the second step value is greater than the first step value of the first parameter M, and N and M are positive integers.

23. The method according to claim 22, characterized in that The interval between the center frequency position of the SSB corresponding to the GSCN in the first GSCN area and the full-bandwidth downlink center frequency position of the transmission channel is an integer multiple of 15kHz.

24. A communication device, characterized in that: The method comprises a unit or module for executing the method according to any one of claims 1 to 7, or a unit or module for executing the method according to any one of claims 14 to 19.

25. A communication device, characterized in that: The method comprises a unit or module for executing the method according to any one of claims 8 to 13, or a unit or module for executing the method according to any one of claims 20 to 23.

26. A communication device, characterized in that: The method comprises a processor and a memory, wherein the memory is used to store program instructions, and when the processor executes the program instructions, the method according to any one of claims 1 to 7 is executed, or when the processor executes the program instructions, the method according to any one of claims 14 to 19 is executed.

27. A communication device, characterized in that: The method comprises a processor and a memory, wherein the memory is used to store program instructions, and when the processor executes the program instructions, the method according to any one of claims 8 to 13 is executed, or when the processor executes the program instructions, the method according to any one of claims 20 to 23 is executed.

28. A computer-readable storage medium, characterized in that The computer storage medium stores computer-readable instructions, which, when executed on a communication device, cause the method according to any one of claims 1 to 23 to be executed.

29. A computer program product, characterized in that The computer program product comprises a computer program which, when run on a computer, causes the computer to perform the method according to any one of claims 1 to 23.

30. A chip, characterized in that: The chip is coupled to a memory and is configured to read and execute program instructions stored in the memory to implement the method according to any one of claims 1 to 23.

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