Communication method and apparatus

Abstract

A communication method and apparatus. The method comprises: generating a secondary synchronization signal, wherein the secondary synchronization signal is a signal obtained on the basis of a first sequence, and the waveform of the secondary synchronization signal is a single-carrier waveform; and sending the secondary synchronization signal. The first sequence is determined on the basis of a second sequence, the first sequence and the second sequence both have a length of L, and element d(m) of the second sequence and element x(n) of the first sequence satisfy: [Equation 1] or [Equation 2], wherein m=(n+c)mod L, 0≤n<L, 0≤m<L, d(m)=0, 1, 2 or 3, and c is p×ID. In the method, the first sequence satisfying the described form exhibits relatively low cross-correlation after modulation, and the waveform of the secondary synchronization signal is the single-carrier waveform, such that the PAPR performance of the secondary synchronization signal can be improved, thereby reducing the PAPR of the secondary synchronization signal, and improving the coverage area of the secondary synchronization signal.

Description

A communication method and apparatus

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410813260.4, filed on June 21, 2024, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0004] In wireless communication systems, network devices send synchronization signals to terminal devices via downlink synchronization channels. These synchronization signals include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). The PSS is used by the terminal device to obtain initial timing and frequency synchronization, as well as a portion of the cell identifier (ID). The SSS is used for further time and frequency synchronization by the terminal device, and to obtain the remaining cell ID. Both the PSS and SSS carry partial information about the cell ID; in other words, the terminal device obtains the cell ID by detecting the PSS and SSS.

[0005] Currently, the peak-to-average power ratio (PAPR) of SSS transmitted by network devices is too high, which can easily cause the power amplifier of the network device to enter the nonlinear region. This results in nonlinear distortion of the signal after passing through the power amplifier, causing spectral spread and in-band signal distortion. To avoid the power amplifier of the network device entering the nonlinear region, the network device performs power back-off when transmitting SSS. This avoids nonlinear distortion, but it reduces the coverage performance of SSS, resulting in limited SSS coverage.

[0006] Therefore, improving the coverage performance of synchronization signals is an urgent problem to be solved. Summary of the Invention

[0007] This application provides a communication method and apparatus for improving signal coverage performance.

[0008] In a first aspect, the present application provides a communication method. This method is applied to the network side. For example, this method is applied to a network device or a component in a network device (such as a circuit, a chip, or a chip system, etc.); or, this method is applied to a module or unit that completes part of the functions of a network device, for example, a central unit (CU), a distributed unit (DU), or a radio unit (RU); or, this method is applied to a device including a network device. For the convenience of description, hereinafter, it is taken as an example that this method is applied to a network device. The communication method includes: generating a secondary synchronization signal, where the secondary synchronization signal is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; and transmitting the secondary synchronization signal. Among them, the first sequence is determined according to a second sequence. The lengths of the first sequence and the second sequence are both L. The element d(m) of the second sequence and the element x(n) of the first sequence satisfy:

[0009] or where m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2, or 3; c is p × ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer.

[0010] Through the method provided by the present application, the first sequence satisfying the above form has a low cross-correlation after modulation, and the waveform of the secondary synchronization signal determined according to the first sequence is a single-carrier waveform, so that the PAPR performance of the secondary synchronization signal can be improved, thereby reducing the PAPR of the secondary synchronization signal and increasing the coverage range of the secondary synchronization signal.

[0011] In a possible implementation, the secondary synchronization signal is a signal obtained by modulating the second sequence, performing conversion precoding, frequency-domain mapping, and N-point inverse fast Fourier transform. Or, the secondary synchronization signal is a signal obtained by performing conversion precoding, frequency-domain mapping, and N-point inverse fast Fourier transform on the first sequence.

[0012] In a possible implementation, generating the secondary synchronization signal includes: modulating the second sequence to obtain the first sequence; performing conversion precoding on the first sequence to obtain a first frequency-domain signal; mapping the first frequency-domain signal to L subcarriers and performing N-point inverse fast Fourier transform to obtain the secondary synchronization signal, where L is an integer greater than 1. Or, obtaining the first sequence, performing conversion precoding on the first sequence to obtain a first frequency-domain signal; mapping the first frequency-domain signal to L subcarriers and performing N-point inverse fast Fourier transform to obtain the secondary synchronization signal; or, obtaining the first frequency-domain signal; mapping the first frequency-domain signal to L subcarriers and performing N-point inverse fast Fourier transform to obtain the secondary synchronization signal. It should be understood that the value of N is generally much larger than L.

[0013] Through this method, the secondary synchronization signal of the single-carrier waveform can be obtained, thereby reducing the PAPR of the secondary synchronization signal, improving the coverage range of the secondary synchronization signal, and improving the coverage performance of the secondary synchronization signal.

[0014] In a possible implementation, the ratio of p to L is greater than a first threshold. In this implementation, since the ratio of p to L is greater than the first threshold, the cyclic shift interval of the sequence can be increased, the influence of the residual error of the primary synchronization signal detection on the secondary synchronization signal can be reduced, and the detection success rate of the secondary synchronization signal can be increased.

[0015] In a possible implementation, the first threshold is the ratio of the cyclic prefix CP length of the secondary synchronization signal to the orthogonal frequency division multiplexing OFDM symbol length. Through this scheme, since the ratio of p to L is greater than the ratio of the CP length to the OFDM symbol length, the error tolerance rate of detecting the secondary synchronization signal on the receiving side can be increased, thereby improving the transmission performance of the secondary synchronization signal.

[0016] In a possible implementation, the first sequence is a Z4 sequence.

[0017] In a second aspect, the present application provides a communication method, which is applied to the terminal side. For example, this method is applied to a terminal device or a component in the terminal device (such as a circuit, a chip, or a chip system, etc.), or this method is applied to a larger device including the terminal device. For the convenience of description, hereinafter, this method is taken as an example of being applied to a terminal device. The communication method includes: detecting a secondary synchronization signal from a network device; the secondary synchronization signal is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; wherein, the first sequence is determined according to a second sequence, the lengths of the first sequence and the second sequence are both L, and the element d(m) of the second sequence and the element x(n) of the first sequence satisfy:

[0018] or where m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; c is p × ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer.

[0019] In one possible implementation, detecting the synchronization signal includes detecting the auxiliary synchronization signal in one of four ways: Method 1, Method 2, Method 3, or Method 4. Method 1 includes acquiring a second sequence, and the terminal device detecting the auxiliary synchronization signal based on the second sequence. In Method 1, the second sequence can be stored in the terminal device, or the second sequence can be generated by the terminal device. The terminal device detecting the auxiliary synchronization signal based on the second sequence includes: the terminal device generating a first sequence based on the second sequence, and the terminal device performing correlation processing on the received auxiliary synchronization signal based on the first sequence, for example, performing correlation calculations on the first sequence and the received auxiliary synchronization signal to detect the synchronization signal.

[0020] Method two includes: acquiring a second sequence, generating a first sequence based on the second sequence, and detecting an auxiliary synchronization signal based on the first sequence. In method two, the second sequence can be stored in the terminal device, or the second sequence can be generated by the terminal device. The terminal device detecting the auxiliary synchronization signal based on the first sequence includes: the terminal device performing correlation processing on the received auxiliary synchronization signal according to the first sequence, for example, performing correlation calculations on the first sequence and the received auxiliary synchronization signal to detect the synchronization signal.

[0021] Method three includes: acquiring a first sequence, and the terminal device detecting the auxiliary synchronization signal based on the first sequence. In method three, the first sequence can be stored in the terminal device, or the first sequence can be generated by the terminal device, for example, the terminal device generates the first sequence based on a second sequence. The terminal device detecting the auxiliary synchronization signal based on the first sequence includes: the terminal device performing correlation processing on the received auxiliary synchronization signal based on the first sequence, for example, performing correlation calculations on the first sequence and the received auxiliary synchronization signal to detect the synchronization signal.

[0022] Method four includes: the terminal device detecting the auxiliary synchronization signal based on sequences in the auxiliary synchronization sequence set, the auxiliary synchronization sequence set including at least one first sequence. In method four, the auxiliary synchronization sequence set can be stored in the terminal device, or the auxiliary synchronization sequence set can be generated by the terminal device. The terminal device detecting the auxiliary synchronization signal based on sequences in the auxiliary synchronization sequence set includes: when detecting the auxiliary synchronization signal, the terminal device can sequentially perform correlation processing on all sequences in the auxiliary synchronization sequence set with the received auxiliary synchronization signal to obtain a correlation value set; one correlation value in the correlation value set corresponds to one sequence in the auxiliary synchronization sequence set; the first sequence corresponding to the auxiliary synchronization signal is determined based on the maximum correlation value in the correlation value set.

[0023] In one possible implementation, the ratio of p to L is greater than a first threshold.

[0024] In one possible implementation, the first threshold is the ratio of the cyclic prefix (CP) length of the secondary synchronization signal to the symbol length of the orthogonal frequency division multiplexing (OFDM).

[0025] In one possible implementation, the first sequence is a Z4 sequence.

[0026] Thirdly, this application provides a communication method applied to a network side. For example, the method may be applied to a network device or a component within the network device (e.g., a circuit, chip, or chip system); or, the method may be applied to a module or unit that performs some functions of the network device, such as a central unit (CU), a distributed unit (DU), or a radio unit (RU); or, the method may be applied to a device including the network device. For ease of description, the following example illustrates the method applied to a network device. The communication method includes: generating a secondary synchronization signal, the secondary synchronization signal being a signal obtained based on a first sequence; the modulation method of the secondary synchronization signal being QPSK; the waveform of the secondary synchronization signal being a single-carrier waveform; and transmitting the secondary synchronization signal.

[0027] The method provided in this application modulates the auxiliary synchronization signal obtained based on the first sequence as QPSK, and the waveform of the auxiliary synchronization signal is a single-carrier waveform, which can improve the PAPR performance of the auxiliary synchronization signal. This can reduce the PAPR of the auxiliary synchronization signal and increase the coverage of the auxiliary synchronization signal.

[0028] In one possible implementation, the auxiliary synchronization signal is a signal obtained by modulating, precoding, frequency mapping, and performing an N-point inverse fast Fourier transform on the first sequence. Alternatively, the auxiliary synchronization signal is a signal obtained by precoding, frequency mapping, and performing an N-point inverse fast Fourier transform on the second sequence.

[0029] In one possible implementation, generating the auxiliary synchronization signal includes: performing QPSK modulation on a first sequence to obtain a second sequence; precoding the second sequence to obtain a first frequency domain signal; mapping the first frequency domain signal onto L subcarriers and performing an N-point inverse Fast Fourier Transform to obtain the auxiliary synchronization signal, where L is an integer greater than 1. Alternatively, the following steps can be taken: obtaining the second sequence; precoding the second sequence to obtain the first frequency domain signal; mapping the first frequency domain signal onto L subcarriers and performing an N-point inverse Fast Fourier Transform to obtain the auxiliary synchronization signal; or obtaining the first frequency domain signal; mapping the first frequency domain signal onto L subcarriers and performing an N-point inverse Fast Fourier Transform to obtain the auxiliary synchronization signal.

[0030] In one possible implementation, the first sequence is determined based on the third and fourth sequences. The lengths of the first, third, and fourth sequences are all L. The elements e(k) of the third sequence, f(m) of the fourth sequence, and x(n) of the first sequence satisfy: x(n) = mod(e(k) + f(m), 2), where k = (n + c1) mod L, m = (n + c2) mod L, c1 and c2 are integers, and 0 ≤ n. <L,0≤m<L,0≤k<L;

[0031] Where c1 is p1×ID1, ID1 takes values ​​in the range [0, K1-1], K1 is a positive integer, c2 is p2×ID2, ID2 takes values ​​in the range [0, K2-1], K1 and K2 are positive integers, the ratio of p1 to L is greater than the first threshold, the ratio of p2 to L is greater than the second threshold, and p1 and p2 are positive integers.

[0032] In this implementation, since the ratio of p1 to L is greater than the first threshold and the ratio of p2 to L is greater than the second threshold, the cyclic shift interval of the sequence can be increased, which can reduce the impact of the residual error of the main synchronization signal detection on the auxiliary synchronization signal and increase the detection success rate of the auxiliary synchronization signal.

[0033] In one possible implementation, the difference between p1 and p2 is less than the third threshold. This method ensures that the cyclic shifts of the fourth and fifth sequences are as large as possible compared to the ratio of CP to OFDM symbols, thus improving the detection efficiency of the auxiliary synchronization signal.

[0034] In one possible implementation, the third threshold is less than or equal to 4.

[0035] In one possible implementation, the first threshold is the ratio of the cyclic prefix (CP) length of the secondary synchronization signal to the OFDM symbol length. This scheme increases the fault tolerance of the receiver in detecting the secondary synchronization signal, thereby improving its transmission performance, since the ratio of p1 to L is greater than the ratio of the CP length to the OFDM symbol length.

[0036] In one possible implementation, the first sequence is the gold sequence.

[0037] Fourthly, this application provides a communication method applied to a terminal side. For example, the method may be applied to a terminal device or a component within the terminal device (e.g., a circuit, chip, or chip system), or it may be applied to a larger device including the terminal device. For ease of description, the following example illustrates the method applied to a terminal device. The communication method includes: detecting a secondary synchronization signal from a network device; the secondary synchronization signal is a signal obtained based on a first sequence; the modulation scheme of the secondary synchronization signal is QPSK; and the waveform of the secondary synchronization signal is a single-carrier waveform.

[0038] In one possible implementation, detecting the synchronization signal includes detecting the auxiliary synchronization signal using one of five methods: method one, method two, method three, method four, or method five. Method one includes acquiring a third sequence and a fourth sequence, and the terminal device detecting the auxiliary synchronization signal based on the third and fourth sequences. In method one, the third and fourth sequences can be stored in the terminal device, or the third and fourth sequences can be generated by the terminal device. The terminal device detecting the auxiliary synchronization signal based on the third and fourth sequences includes: the terminal device generating a first sequence based on the third and fourth sequences, determining a second sequence based on the first sequence, and performing correlation processing on the received auxiliary synchronization signal based on the second sequence, for example, performing correlation calculations on the second sequence and the received auxiliary synchronization signal to detect the synchronization signal.

[0039] Method two includes: acquiring a first sequence, and the terminal device detecting an auxiliary synchronization signal based on the first sequence. In method two, the first sequence can be stored in the terminal device, or the first sequence can be generated by the terminal device; the terminal device detecting the auxiliary synchronization signal based on the first sequence includes: the terminal device determining a second sequence based on the first sequence, and the terminal device performing correlation processing on the received auxiliary synchronization signal based on the second sequence, for example, performing correlation calculations on the second sequence and the received auxiliary synchronization signal to detect the synchronization signal.

[0040] Method 3 includes: acquiring a first sequence, determining a second sequence based on the first sequence, and the terminal device detecting the auxiliary synchronization signal based on the second sequence. In Method 3, the first sequence can be stored in the terminal device, or the first sequence can be generated by the terminal device; the terminal device detecting the auxiliary synchronization signal based on the second sequence includes: the terminal device performing correlation processing on the received auxiliary synchronization signal according to the second sequence, for example, performing correlation calculations on the second sequence and the received auxiliary synchronization signal to detect the synchronization signal.

[0041] Method four includes: acquiring a second sequence, and the terminal device detecting an auxiliary synchronization signal based on the second sequence. In method four, the second sequence can be stored in the terminal device, or the second sequence can be generated by the terminal device; the terminal device detecting the auxiliary synchronization signal based on the second sequence includes: the terminal device performing correlation processing on the received auxiliary synchronization signal according to the second sequence, for example, performing correlation calculations on the second sequence and the received auxiliary synchronization signal to detect the synchronization signal.

[0042] Method five includes: the terminal device detecting the auxiliary synchronization signal based on sequences in the auxiliary synchronization sequence set, the auxiliary synchronization sequence set including at least one second sequence. In method five, the auxiliary synchronization sequence set can be stored in the terminal device, or the auxiliary synchronization sequence set can be generated by the terminal device. The terminal device detecting the auxiliary synchronization signal based on sequences in the auxiliary synchronization sequence set includes: when detecting the auxiliary synchronization signal, the terminal device can sequentially perform correlation processing on all sequences in the auxiliary synchronization sequence set with the received auxiliary synchronization signal to obtain a correlation value set; one correlation value in the correlation value set corresponds to one sequence in the auxiliary synchronization sequence set; the second sequence corresponding to the auxiliary synchronization signal is determined based on the maximum correlation value in the correlation value set.

[0043] In one possible implementation, the first sequence is determined based on the third and fourth sequences. The lengths of the first, third, and fourth sequences are all L. The elements e(k) of the third sequence, f(m) of the fourth sequence, and x(n) of the first sequence satisfy: x(n) = mod(e(k) + f(m), 2), where k = (n + c1) mod L, m = (n + c2) mod L, c1 and c2 are integers, and 0 ≤ n. <L,0≤m<L,0≤k<L;

[0044] Where c1 is p1×ID1, ID1 takes values ​​in the range [0, K1-1], K1 is a positive integer, c2 is p2×ID2, ID2 takes values ​​in the range [0, K2-1], K1 and K2 are positive integers, the ratio of p1 to L is greater than the first threshold, the ratio of p2 to L is greater than the second threshold, and p1 and p2 are positive integers.

[0045] In one possible implementation, the difference between p1 and p2 is less than the third threshold.

[0046] In one possible implementation, the third threshold is less than or equal to 4.

[0047] In one possible implementation, the first threshold is the ratio of the cyclic prefix (CP) length of the secondary synchronization signal to the symbol length of the orthogonal frequency division multiplexing (OFDM).

[0048] In one possible implementation, the first sequence is the gold sequence.

[0049] Fifthly, this application also provides a communication device capable of implementing any of the methods provided in any of the first to fourth aspects. This 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 aforementioned functions.

[0050] In one possible implementation, the communication device includes a processor configured to support the communication device in performing corresponding functions of the network device or terminal device described above. The communication device may also include a memory coupled to the processor, which stores necessary program instructions and data for the communication device. Optionally, the communication device further includes interface circuitry for supporting communication between the communication device and devices such as terminal devices.

[0051] In one possible implementation, the communication device includes corresponding functional modules, each used to implement the steps in the above method. The functions can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

[0052] In one possible implementation, the communication device includes a processing unit and a communication unit, which can perform the corresponding functions in the above method examples, as described in the methods provided in any of the first to fourth aspects, and will not be repeated here.

[0053] A sixth aspect provides a communication device, including a processor and an interface circuit. The interface circuit is 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 implements the functional modules of the methods in any possible implementation of any of the first to fourth aspects through logic circuits or by executing computer programs or instructions. Optionally, the communication device further includes a memory for storing computer programs or instructions.

[0054] In a seventh aspect, a computer-readable storage medium is provided that stores a computer program or instructions that, when executed by a processor or when run on a computer, cause the computer to implement the methods in any possible implementation of any of the first to fourth aspects.

[0055] Eighthly, a computer program product storing instructions is provided, which, when read and executed by a computer, implements the method in any possible implementation of any of the first to fourth aspects.

[0056] A ninth aspect provides a circuit for performing the methods in any possible implementation of any of the first to fourth aspects described above, the circuit including chip circuitry. Optionally, the circuit may also be coupled to a memory.

[0057] In a tenth aspect, a chip is provided, the chip including a processor, which, when executing a computer program or instructions, implements the methods in any possible implementation of any of the first to fourth aspects. Optionally, the chip may further include a memory, and the chip may be composed of chips or may include chips and other discrete devices.

[0058] Eleventhly, a communication device is provided, including a processor that implements the methods in any possible implementation of any of the first to fourth aspects by means of logic circuits or by executing computer programs or instructions. Alternatively, the processor is configured to execute computer programs or instructions stored in a memory to implement the methods in any possible implementation of any of the first to fourth aspects.

[0059] In a twelfth aspect, a communication apparatus is provided, comprising a unit or module for performing a method in any possible implementation of any of the first to fourth aspects described above.

[0060] In a thirteenth aspect, embodiments of this application also provide a communication system. The communication system includes: a network device for implementing the methods of the first aspect and any possible implementations thereof; and a terminal device for implementing the methods of the second aspect and any possible implementations thereof. Alternatively, the communication system includes: a network device for implementing the methods of the third aspect and any possible implementations thereof; and a terminal device for implementing the methods of the fourth aspect and any possible implementations thereof. Attached Figure Description

[0061] Figure 1 is a schematic diagram of a communication system provided in an embodiment of this application;

[0062] Figure 2 is a schematic diagram of two typical protocol stacks of the base station provided in the embodiments of this application;

[0063] Figure 3 shows a schematic diagram of a synchronization signal time-frequency resource;

[0064] Figure 4 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0065] Figure 5 is a schematic diagram of a single-carrier waveform generation process provided in an embodiment of this application;

[0066] Figure 6 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0067] Figure 7 is a schematic diagram of the communication device provided in an embodiment of this application;

[0068] Figure 8 is a schematic diagram of the structure of the communication device provided in the embodiment of this application. Detailed Implementation

[0069] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The terms "first," "second," and corresponding terminology in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The methods and apparatus provided in the embodiments of this application are based on the same or similar technical concepts. Since the principles by which the methods and apparatus solve problems are similar, the implementation of the apparatus and methods can refer to each other, and repeated details will not be repeated.

[0070] The technical solutions provided in the embodiments of this application can be applied to communication systems related to the 3rd Generation Partnership Project (3GPP), such as Long Term Evolution (LTE) communication systems, 5th Generation (5G) mobile communication systems, or to future communication systems or other similar communication systems. Furthermore, the technical solutions provided in the embodiments of this application can be applied to cellular links, public land mobile networks (PLMNs), machine-to-machine (M2M) networks, Internet of Things (IoT) networks, or other networks. They can also be applied to links between devices, such as device-to-device (D2D) links. D2D links can also be called sidelinks, which are also referred to as secondary links or auxiliary links.

[0071] Please refer to Figure 1, which illustrates a communication system applicable to an embodiment of this application. The communication system includes a wireless access network 100 and a core network 200. Optionally, the communication system may also include the Internet (Figure 1 uses this as an example).

[0072] The wireless access network 100 may include at least one network device and at least one terminal device. For example, the wireless access network 100 includes two network devices, 110a and 110b, and terminal devices 120a to 120j. The network architecture shown in Figure 1 is only schematic; the number of terminal devices and / or network devices may be fewer or more. The communication system described in the embodiments of this application is for the purpose of more clearly illustrating the technical solutions of the embodiments of this application and does not constitute a limitation on the communication system to which the embodiments of this application are applicable. For example, the communication system may also include other devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1. As those skilled in the art will know, with the evolution of network architecture, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems. When applying the technical solutions of the embodiments of this application to other communication systems, the devices, components, modules, etc. in the embodiments can be replaced with corresponding devices, components, modules in other communication systems without limitation.

[0073] In this embodiment, the network device refers to a radio access network (RAN) device. The RAN can be a 3GPP-related cellular system, such as a 5G / new radio (NR) mobile communication system, or a future-oriented evolution system (e.g., a 6G mobile communication system). The RAN can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a virtualized RAN (vRAN), etc. The RAN can also be a communication system that integrates two or more of the above systems. The RAN device can also be referred to as a RAN node, RAN entity, or access node, etc.

[0074] In one possible scenario, a RAN node can be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a next-generation base station in a 6G mobile communication system, or a base station in a future mobile communication system. A RAN node can also be a macro base station, a micro base station, an indoor station, a relay node, a donor / host node, or a radio controller. RAN nodes can also be servers, wearable devices, vehicles, or in-vehicle equipment. For example, in V2X technology, a RAN node can be a roadside unit (RSU).

[0075] In another possible scenario, the RAN node can be a module or unit that performs some of the functions of the base station; or multiple RAN nodes can cooperate to assist terminal equipment in achieving wireless access, with different RAN nodes performing some of the functions of the base station. For example, the RAN node can be a centralized unit (CU), a distributed unit (DU), or a radio unit (RU). The function of the CU can be implemented by a single entity or by different entities. For example, the function of the CU can be further divided, that is, the control plane and the user plane can be separated and implemented by different entities, namely the control plane CU entity (i.e., CU-control plane (CP) entity) and the user plane CU entity (i.e., CU-user plane (UP) entity). The CU-CP entity and the CU-UP entity can be coupled with the DU to jointly complete the function of the RAN node. The CU and DU can be set up separately or included in the same network element, such as in the baseband unit (BBU). Any of the units among the CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented by software modules, hardware modules, or a combination of software modules and hardware modules.

[0076] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples.

[0077] The CU and DU can be configured according to the protocol layer functions of the wireless network they implement: for example, the CU can be configured to implement the functions of the Packet Data Convergence Protocol (PDCP) layer and above (such as the Radio Resource Control (RRC) layer and / or the Service Data Adaptation Protocol (SDAP) layer); the DU can be configured to implement the functions of the protocol layers below the PDCP layer (such as the Radio Link Control (RLC) layer, the Media Access Control (MAC) layer, and / or the Physical (PHY) layer). For specific descriptions of the above protocol layers, please refer to the relevant 3GPP technical specifications or the technical specifications of other applicable communication protocols.

[0078] For example, please refer to Figure 2, which is a schematic diagram of two typical protocol stacks of a base station provided in the embodiments of this application. In base station (1), the base station is divided into CU and DU. CU is configured to implement the functions of protocol layers above PDCP (e.g., RRC layer and / or SDAP layer, etc.); DU is configured to implement the functions of protocol layers below PDCP (e.g., RLC layer, MAC layer, and / or PHY layer, etc.). CU and DU communicate with each other based on the F1 interface. In base station (2), the base station is divided into CU and DU. CU includes CU-CP and CU-UP. CU-CP is used to implement the control plane functions of CU, and CU-UP is used to implement the user plane functions of CU. CU-CP and CU-UP can communicate based on the E1 interface. CU-CP and DU communicate based on the F1 interface (also called F1-C) that supports the control plane. CU-UP and DU communicate based on the F1 interface (also called F1-U) that supports the user plane. CU-CP is configured to implement the control plane and RRC layer functions of the PDCP layer, and CU-UP is configured to implement the user plane and SDAP layer functions of the PDCP layer. DU is configured to implement the functions of protocol layers below the PDCP layer (such as RLC, MAC, and / or PHY layers).

[0079] The above division of the processing functions of CU and DU according to protocol layers is merely an example; other division methods are also possible, and this application does not limit this. For example, in one design, CU or DU can be further divided into processing functions with protocol layers. In one design, some functions of the RLC layer and the functions of the protocol layer above the RLC layer are located in the CU, while the remaining functions of the RLC layer and the functions of the protocol layer below the RLC layer are located in the DU.

[0080] In another possible design, the DU and RU collaborate to implement the PHY layer functionality, or, more specifically, a portion of the PHY layer functionality of the DU can be moved to the RU. A DU can be connected to one or more RUs. The functions of the DU and RU can be configured in various ways depending on the design. For example, the DU may be configured to implement baseband functions, and the RU may be configured to implement mid-RF functions. Alternatively, the DU may be configured to implement higher-level functions in the PHY layer, and the RU may be configured to implement lower-level functions in the PHY layer, or both lower-level and RF functions. Higher-level functions in the physical layer may include a portion of the physical layer's functionality closer to the MAC layer, while lower-level functions may include another portion of the physical layer's functionality closer to the mid-RF side. This application does not limit the specific functions of the DU and RU. The interface between the DU and RU can be referred to as a fronthaul interface.

[0081] In the embodiments of this application, the means for implementing the functions of the network device can be the network device itself, or it can be a means that supports the network device in implementing the functions, such as a chip system or a combination of devices or components that can implement the functions of the network device. This means can be installed in the network device. The embodiments of this application do not limit the specific technology or specific device form used in the network device.

[0082] In this application embodiment, anything capable of data communication with a base station can be considered a terminal device. Terminal devices are also called terminals, terminal equipment, user equipment (UE), mobile stations, or mobile terminals, etc. Terminal devices can be widely used in various scenarios. For example, terminal devices can be: mobile phones, computers, mobile internet devices (MID), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, stations (STA), robotic arms, cameras, robots, vehicles, drones, helicopters, airplanes, ships, or smart home devices (such as televisions, air conditioners, robot vacuums, speakers, set-top boxes), relays, customer premises equipment (CPE), etc.

[0083] Furthermore, in this embodiment, the terminal device can also be a terminal device in an IoT system, such as a water meter or electricity meter. IoT is an important component of future information technology development. Its main technical characteristic is connecting objects to networks through communication technology, thereby realizing an intelligent network that enables human-machine interconnection and object-to-object interconnection.

[0084] When the terminal device is applied to V2X, it can also be called a V2X device, such as a smart car, digital car, unmanned car, driverless car, pilotless car, autonomous car, pure electric vehicle, hybrid electric vehicle (HEV), range-extended electric vehicle (REEV), plug-in hybrid electric vehicle (PHEV), new energy vehicle, and roadside unit (RSU).

[0085] The various terminal devices described above, if located on a vehicle (e.g., placed / installed inside the vehicle), can all be considered in-vehicle terminal devices. In-vehicle terminal devices can be built into a vehicle's in-vehicle module, in-vehicle component, in-vehicle chip, or in-vehicle unit as one or more components or units. The vehicle can implement the methods of this application through the built-in in-vehicle module, in-vehicle component, in-vehicle chip, or in-vehicle unit. In-vehicle terminal devices can be vehicle equipment, in-vehicle modules, vehicles, on-board units (OBU), roadside units (RSU), in-vehicle systems (or in-vehicle transmitting units) (telematics boxes, T-boxes), chips, or systems on chips (SOCs), etc. These chips or SOCs can be installed in the vehicle, OBU, RSU, or T-box.

[0086] In the embodiments of this application, the device for implementing the functions of the terminal device can be the terminal device itself, or a device capable of supporting the terminal device in implementing the functions, such as a chip system or a combination of devices or components capable of implementing the functions of the terminal device. This device can be installed in the terminal device. The embodiments of this application do not limit the specific technology or specific device form used in the terminal device.

[0087] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these dozen or more items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0088] In this application, the Z4 sequence refers to sequence A that satisfies the following condition: length is 2. r The binary sequence obtained by projecting a sequence A of -1 onto a binary field has a period of 2. r -1, and the binary sequence is an m-sequence generated by projecting the primitive polynomial of sequence A onto the binary field. In possible implementations, the Z4 sequence can be a quaternion sequence, that is, the Z4 sequence includes elements with 4 possible values. It should be noted that the embodiments of this application do not limit the number of possible values ​​for the elements included in the Z4 sequence. For example, the Z4 sequence can also be a hexaternion sequence or an octet sequence, etc.

[0089] Network devices transmit a synchronous signal / physical broadcast channel block (SS / PBCH block or SSB) to terminal devices via the downlink synchronization channel. As shown in Figure 3, the SSB includes the PSS, SSS, and physical broadcast channel (PBCH). In the time domain, one SSB occupies four orthogonal frequency division multiplexing (OFDM) symbols (symbols 0 to 3). In the frequency domain, one SSB occupies 20 resource blocks (RBs), each RB containing 12 subcarriers, totaling 240 subcarriers numbered 0 to 239. The PSS is located on the middle 127 subcarriers of symbol 0, and the SSS is located on the middle 127 subcarriers of symbol 2. To protect the PSS and SSS, guard subcarriers are reserved on both sides of the PSS and SSS, as shown in the blank areas on both sides of the SSS in the figure. These guard subcarriers are not used to carry signals. PBCH occupies all subcarriers of symbols 1 and 3, as well as a portion of the remaining subcarriers of symbol 2, excluding those occupied by SSS.

[0090] The PSS (Physical System Sequence) is used by the terminal device to obtain initial timing and frequency synchronization and carries a portion of the cell identifier (ID). The SSS (Secondary System Sequence) is used to provide another portion of the cell identifier. The PBCH (Physical Branch Message Council) carries the critical system messages required for the UE to access the network. The terminal device can determine the physical cell identity (PCI) based on the SSS and PSS.

[0091] Among them, PCI is used to identify cells at the physical layer, and can also be called cell identifier. Terminal devices can identify cells through network identity 1 (NIC). ) and network identity 2, Determine the PCI. For example, It can be obtained from PSS. It can be obtained from SSS.

[0092] PSS uses m-sequence construction, and the specific sequence generation is shown in Formula 1 below:

[0093] SSS is constructed using the gold sequence as shown in Formula 2 below:

[0094] The community identification number can be calculated using the following formula 3:

[0095] in, The set of values ​​for is {0, 1, 2}. The set of values ​​for is {0, 1, 2, ..., 335}. Therefore, there are a total of 1008 = 3 * 336 cell identifiers. When the UE detects the downlink synchronization signal, it first performs a two-dimensional time-frequency search on the PSS. After the UE detects the PSS signal, it first performs frequency correction and then time synchronization. Since the PSS carries... There are three possible sequences in total, which the UE detects. Then, substitute it into the SSS detection, once It is confirmed that there are a total of 336 possible SSS sequences. The UE needs to use 336 different SSS sequences to perform cross-correlation detection on the SSS, and the SSS sequence corresponding to the maximum cross-correlation value is the SSS sequence actually sent by the network side.

[0096] Currently, SSS (Special Support Array) is generated using gold sequence / gold sequence, meaning the gold sequence is one type of sequence used to generate SSS. In the future, the frequency at which SSS is transmitted may increase, leading to greater path loss. To mitigate the impact of increased path loss, the transmission power of the SSS can be increased. However, increasing the transmission power of the SSS will result in an excessively high peak-to-average power ratio (PAPR), causing the power amplifier in the terminal equipment to enter the nonlinear region. This leads to nonlinear distortion of the SSS after passing through the power amplifier, necessitating power back-off. Consequently, SSS detection performance deteriorates, resulting in limited SSS coverage.

[0097] To address the aforementioned technical problems, this application provides a method for sending SSS, which can improve SSS coverage.

[0098] The method will be described below from the perspective of interaction between terminal devices and network devices. The steps executed by the terminal device can also be implemented by components within the terminal device (such as a baseband chip, or other processing units or processor modules). Similarly, the steps executed by the network device can also be implemented by components within the network device (such as a baseband chip, or other processing units or processor modules).

[0099] Figure 4 shows a flowchart of a communication method provided in an embodiment of this application. The method includes:

[0100] Step 401: The network device generates a secondary synchronization signal.

[0101] Among them, the secondary synchronization signal is a signal obtained based on the first sequence, and the first sequence can be referred to as the secondary synchronization signal sequence. The secondary synchronization signal can be used to determine the physical cell identifier. For example, according to and the physical cell identifier can be determined, where the secondary synchronization signal can carry which can be determined according to the primary synchronization signal. Another example is that only the secondary synchronization signal carries the physical cell identifier. This application does not limit the specific manner in which the secondary synchronization signal carries the physical cell identifier.

[0102] In this application, the first sequence can be a phase sequence. For example, the first sequence is a Z4 sequence. Among them, the phase sequence refers to a sequence element whose value is one of {1, -1, j, -j}, where j is an imaginary number. The multiplication complexity during the correlation detection of the phase sequence can be ignored, so the detection complexity of the first sequence can be reduced.

[0103] How the first sequence is specifically determined is not limited in this application. In one implementation, the first sequence is determined according to the second sequence. The lengths of the first sequence and the second sequence are both L. For example, the second sequence is a Z4 sequence determined according to a recurrence formula and an initial value, and the first sequence is a sequence obtained by circularly shifting and modulating the Z4 sequence. The element d(m) of the second sequence and the element x(n) of the first sequence satisfy:

[0104] or where m = (n + c) mod L, c is an integer, A is a constant, for example, A = 1; 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; c is p×ID, the value range of ID is [0, K - 1], K is a positive integer, j is an imaginary number, p is a positive integer greater than or equal to 0, and mod is the modulo operation. c can refer to the cyclic shift value, and p can refer to the cyclic shift interval. Among them, the value ranges of L and c and the value range of ID can be preset or predefined; for example, when K is 6, the length L of the first sequence is 127, and the value of p is 15, then the corresponding cyclic shift value c can be any value in 0, 15, 30, 45, 60, 75; or when K is 2, the length L of the first sequence is 255, and the value of p is 125, then the corresponding cyclic shift value c can be any value in 0, 125. ID can be used to determine the physical cell identifier. For example, there is a mapping relationship between ID and the physical cell identifier, and this mapping relationship is preset. For example, this ID and there is a mapping relationship, and this mapping relationship is preset. For example, this mapping relationship is a is an integer greater than 0. In the following description, is referred to as the first cell identifier. It should be understood that the first cell identifier can also be the physical cell identifier.

[0105] It is important to understand that m = (n + c) mod L means that the sequence [d[n]] is cyclically shifted to the left by c elements to obtain the sequence [d[m]]. This indicates modulation of the sequence [d[m]]. Taking [d[m]] = [0,1,2,3] as an example, then...

[0106] In one possible implementation, p is greater than a first threshold. For example, the first threshold is the ratio of the length of the cyclic prefix (CP) of the secondary synchronization signal to the length of the OFDM symbol. For example, if the first threshold is 1 / 10, p can be 2.

[0107] Optionally, p = floor(L / K), where floor rounds down; or p = ceil(L / K), where ceil rounds up; or p = round(L / K), where round rounds to the nearest integer. The value of p can also be preset or predefined.

[0108] It is important to understand that the above method of selecting the value of p maximizes the minimum distance between the two cyclic shift values, thereby ensuring the detection performance of the auxiliary synchronization signal to the greatest extent.

[0109] In one possible implementation, the ratio of p to L is greater than a first threshold. Since the ratio of p to L is greater than the ratio of the CP length to the OFDM symbol length, this increases the fault tolerance of the receiver in detecting the secondary synchronization signal, making it more robust to residual delay errors in PSS detection, thereby improving the transmission performance of the secondary synchronization signal.

[0110] For example, if the cyclic shift interval of the first sequence is 1 and the cyclic shift value of the first sequence is c=1, and the cyclic shift offset corresponding to the residual error detected by the PSS is 1, then the receiver on the receiving side will misdetect the cyclic shift value of the first sequence as 2, resulting in detection failure. However, in this application, by increasing the cyclic shift interval, for example, if the cyclic shift interval of the first sequence is p=7, then the cyclic shift value of the first sequence can be 0, 7, 14, 21, etc. If the cyclic shift value of the first sequence is c=7, and the cyclic shift offset corresponding to the residual error detected by the PSS is 1, then the receiver on the receiving side will misdetect the cyclic shift value of the first sequence as 8. However, since there is no cyclic shift value of 8 in the first sequence, the receiving side considers the actual cyclic shift value to be the closest to 8, i.e., determines the cyclic shift value to be 7, thus successfully detecting the auxiliary synchronization signal.

[0111] In this application, the second sequence can be determined based on the initial values ​​and the primitive polynomials. The initial values ​​of the second sequence belong to the initial value set, and any two initial values ​​in the initial value set are different. The elements of the second sequence satisfy a recurrence relation, which corresponds one-to-one with the primitive polynomials.

[0112] For example, the recurrence relation of the second sequence satisfies: The primitive polynomial f(x) of the second sequence satisfies: a i ∈{0,1,2,P-1}, where P is a positive integer greater than 3 and r is a positive integer. When P = 4, the second sequence includes 4 values ​​(i.e., 0,1,2,3), and is therefore called a quaternion series; when P = 6, the second sequence includes 6 values ​​(i.e., 0,1,2,3,4,5), and is therefore called a hexaternion series; and so on.

[0113] The following example, using the Z4 sequence as an example, illustrates the generation process of the second sequence:

[0114] Taking a second sequence of length 127 as an example, the primitive polynomial of the second sequence is f(x) = x. 7 +2x 4 +x+3, or, the primitive polynomial of the second sequence is f(x)=x 7 +3x 4 +2x 2 +3; The recurrence relation of the second sequence can satisfy: d(m+7)=mod(2·d(m+4)+3·d(m+1)+d(m),4), or, the recurrence relation of the second sequence can satisfy: d(m+7)=mod(d(m+4)+2·d(m+2)+d(im),4). Taking the length of the second sequence as 255 as an example, the primitive polynomial of the second sequence is x. 8 +x 5 +3x 3 +x 2 +2x+1, the recursive relation of the second sequence is d(m+8)=mod(3·d(m+5)+d(m+3)+3·d(m+2)+2·d(m+1)+3·d(m),4).

[0115] The set of all possible initial values ​​for the second sequence is called the initial value set. The second sequence can be generated based on any initial value within this initial value set. The initial value set is predefined by the protocol; or, it is agreed upon by the network device and the terminal device; or, it is configured by the network device for the terminal device. The initial value set can be pre-stored in the network device or in the terminal device. This application does not limit the specific implementation of the initial value set. For example, the initial value set can be represented by a table, where each row corresponds to an initial value, and the corresponding initial value is determined based on the row index.

[0116] In one possible implementation, the sequence set consisting of all sequences obtainable from the initial value set is predefined by the protocol, and this sequence set includes a second sequence. Alternatively, the sequence set is agreed upon by the network device and the terminal device; or, the sequence set is configured by the network device to the terminal device. This sequence set can be pre-stored in the network device or the terminal device. The specific implementation of the sequence set is not limited in this application. For example, the sequence set can be represented by a table, where each row corresponds to a sequence, and the corresponding sequence can be determined based on the row index.

[0117] In this embodiment, any two initial values ​​within the initial value set are different. This, to a certain extent, avoids the possibility of sequences generated based on the initial values ​​within the initial value set being cyclically shifted from each other. Therefore, since any two initial values ​​within the initial value set are different, and the sequence generated based on the initial values ​​within the initial value set carries the cell identifier, it can be ensured that the cell identifier is not confused, that is, it can be ensured that cell identifier confusion will not occur when detecting the secondary synchronization signal.

[0118] Optionally, any two initial values ​​in the initial value set are the same after modulo 2. This ensures that the binary sequence set obtained after modulo 2 of any two initial values ​​is the same, which means that the set of cyclic shift values ​​used for each initial value is the same. Thus, for different initial values, the cyclic shift value of the auxiliary synchronization signal can be detected based on the same detection mechanism, resulting in lower implementation complexity.

[0119] The set of initial values ​​for the second sequence varies depending on its length and the recurrence relation / primitive polynomial. Several possible sets of initial values ​​are illustrated below with specific examples.

[0120] Example 1: The length of the second sequence is 127, and the recurrence relation of the second sequence satisfies: d(m+7) = mod(2·d(m+4) + 3·d(m+1) + d(m), 4) or (m+7) = mod(d(m+4) + 2·d(m+2) + d(im), 4); or, the length of the second sequence is 127, and the primitive polynomial of the second sequence is x. 7 +2x 4 +x+3 or x 7 +3x 4 +2x 2 +3.

[0121] In Example 1, the initial value of the second sequence is [d(6),d(5),d(4),d(3),d(2),d(1),d(0)], and the initial value set 1 to which this initial value belongs includes one or more of the following sequences: [1,0,0,0,0,0,0,0], [3,0,0,0,0,0,0], [1,0,0,0,2,2,2], [3,2,0,0,0,0,0], [1,2,2,2,0,0,0], [1,0,0,0,0,0,2], [3,0,0,0,0,0,2], [3,2,2,2,0,0,0], [1,2,0,0,0,0,0], [3,0,0,0,2,2,2], [1,2,0,2,0,2] [,0],[3,2,2,0,0,0,0],[1,2,2,2,2,2,2],[1,2,2,0,0,2,2],[3,0,2,2,0,0,0],[1,2,0,2,0,0,0],[1,0,2,0,0,0,0],[1,0,2,0,2,0,2],[1,0,0,0,0] [2,0,2],[3,2,0,0,2,2,2],[1,0,2,2,2,2,0],[1,0,0,0,0,2,0],[3,0,0,0,0,2,0],[3,2,2,2,0,0,2],[3,2,0,0,0,0,2],[3,0,0,0,2,2,0],[1,0,0 [0,0,2,2],[3,0,0,0,0,2,2],[1,0,0,0,2,2,0],[1,2,0,0,0,0,2],[1,2,2,2,0,0,2],[3,2,2,2,2,2,2],[1,2,2,0,0,0,0],[3,2,0,2,0,2,0],[3, [0,2,2,2,2,0],[1,2,0,0,2,2,2],[3,0,0,0,2,0,2],[3,0,2,0,2,0,2],[3,0,2,0,0,0,0],[3,2,0,2,0,0,0],[1,0,2,2,0,0,0],[3,2,2,0,0,2,2], [1,0,0,2,0,2,2],[1,0,0,2,0,0,0],[1,2,0,2,2,0,2],[1,0,2,2,0,0,2],[3,2,2,0,2,0,2],[3,2,0,0,2,2,0],[3,0,2,0,2,2,2],[3,2,2,2,2,2] [0],[3,2,2,0,2,2,2],[3,2,0,0,2,0,2],[3,0,0,2,0,2,2],[1,2,0,2,2,2,2],[1,2,0,0,2,2,0],[3,0,0,2,0,2,0],[1,0,2,2,2,2,2],[1,2,2,2,0]2,0]，[1,2,2,2,2,0,2]，[1,2,2,0,2,0,0]，[3,0,2,2,2,2,2]，[3,0,2,0,2,0,0]，[3,2,2,0,0,0,2]，[1,0,2,0,2,2,2]，[3,0,0,2,0,0,0]，[1,0,2,0,0,2,0]，[3,2,0,0,0,2,2]，[1,0,0,0,2,0,0]，[3,0,2,0,0,2,2]，[3,2,2,0,2,0,0]，[3,0,0,0,2,0,0]，[3,2,2,2,0,2,2]，[3,2,0,0,0,2,0]，[1,2,0,0,0,2,0]，[1,2,2,2,0,2,2]，[1,0,2,0,2,0,0]，[3,2,0,2,0,0,2]，[3,2,2,0,0,2,0]，[1,2,0,2,0,2,2]，[1,0,2,0,0,0,2]，[1,2,2,2,2,2,0]，[3,2,2,2,0,2,0]，[1,2,0,0,0,2,2]，[1,2,2,0,0,0,2]，[3,0,2,2,0,0,2]，[3,0,2,0,0,0,2]，[3,2,0,2,0,2,2]，[1,2,2,0,0,2,0]，[1,2,0,2,0,0,2]，[1,2,2,0,2,0,2]，[3,2,0,2,2,0,2]，[1,0,0,2,0,2,0]，[1,0,2,0,0,2,2]，[3,0,2,0,0,2,0]，[3,2,0,2,2,2,2]，[3,2,2,2,2,0,2]，[1,2,0,0,2,0,2]，[1,2,2,0,2,2,2]，[3,0,0,2,2,2,2]，[3,2,2,2,2,0,0]，[1,2,2,2,2,0,0]，[3,0,2,2,0,2,0]，[1,2,2,0,2,2,0]，[3,2,0,0,2,0,0]，[3,0,2,2,2,0,2]，[1,0,0,2,2,0,0]，[1,2,0,2,2,2,0]，[3,0,0,2,2,0,2]，[3,0,0,2,0,0,2]，[1,0,0,2,2,2,2]，[3,2,0,2,2,0,0]，[1,0,0,2,2,2,0]，[3,0,0,2,2,0,0]，[1,0,2,2,2,0,0]，[1,0,2,2,0,2,2]，[3,0,2,2,2,0,0]，[3,0,2,2,0,2,2]，[3,2,0,2,2,2,0]，[3,2,2,0,2,2,0]，[1,0,0,2,0,0,2]，[1,[2,0,0,2,0,0], [1,0,2,2,2,0,2], [3,0,2,0,2,2,0], [1,2,0,2,2,0,0], [1,0,2,0,2,2,0], [1,0,0,2,2,0,2], [3,0,0,2,2,2,0], or [1,0,2,2,0,2,0].

[0122] Example 2: The length of the second sequence is 255, and the recurrence relation of the second sequence is d(m+8) = mod(3·d(m+5) + d(m+3) + 3·d(m+2) + 2·d(m+1) + 3·d(m), 4); or, the length of the second sequence is 255, and the primitive polynomial of the second sequence is x. 8 +x 5 +3x 3 +x 2 +2x+1.

[0123] In Example 2, the initial value of the second sequence is [d(6),d(5),d(4),d(3),d(2),d(1),d(0)], and the initial value set 2 to which this initial value belongs includes one or more of the following sequences: [3,0,0,0,0,0,0,0], [1,0,0,0,0,0,0,0], [3,2,2,0,2,0,2,2], [3,2,0,0,0,0,0,0], [3,0,0,2,0,2,0,0], [3,0,0,0,0,0,0,2], [1,0,0,0,0,0,0,2], [1,0,0,2,0,2,0,0], [1,2,0,0,0,0,0,0], [1,2,2,0,2] [0,2,2],[3,2,0,2,0,2,0,2],[1,0,2,0,0,0,0,0],[3,2,2,2,2,2,2,2],[3,0,2,0,2,2,0,0],[3,2,0,2,0,2,0,0],[1,2,0,0,0,0,0,2],[1,2,2,0 [0,0,0,0],[3,0,2,0,2,0,2,0],[1,2,2,2,0,2,2,2],[3,0,2,0,2,2,2],[3,0,0,2,2,0,2,0],[3,0,0,0,0,0,2,0],[1,0,0,0,0,0,2,0],[1,0,0,2 [0,2,0,2],3,2,0,0,0,0,0,2],[1,2,2,0,2,0,2,0],[3,0,0,0,0,0,2,2],[1,0,0,0,0,0,2,2],[3,2,2,0,2,0,2,0],[3,0,0,2,0,2,0,2],[1,2,2,2] [2,2,2,2],[3,0,2,0,0,0,0,0],[1,2,0,2,0,2,0,2],[1,0,0,2,2,0,2,0],[1,0,2,0,2,0,2,2],[3,2,2,2,0,2,2,2],[1,0,2,0,2,0,2,0],[3,2,2, [0,0,0,0,0],[1,2,0,2,0,2,0,0],[1,0,2,0,2,2,0,0],[1,0,0,2,2,2,0,0],[1,2,0,2,0,0,0,0],[3,0,2,2,2,0,0,0],[1,2,0,2,0,2,2,2],[3,0,2 [0,0,2,0,2],[3,2,2,2,0,0,0,0],[3,2,2,2,0,0,0,2],[3,0,2,2,0,0,2,0],[1,2,0,0,2,2,2,2],[1,2,2,2,0,2,0,0],[1,2,0,2,0,0,2,0],[3,0,2,2,2,2,2,0]，[3,2,0,2,2,0,2,0]，[3,0,2,0,0,2,2,2]，[1,2,2,2,0,2,0,2]，[1,2,0,0,2,0,2,2]，[1,2,2,0,2,0,0,0]，[3,0,0,0,2,2,0,2]，[1,0,2,2,0,2,2,2]，[3,0,0,0,2,2,2,0]，[1,0,0,2,0,0,0,0]，[3,0,0,2,2,2,0,0]，[1,2,2,0,2,2,2,0]，[3,2,0,0,0,2,2,2]，[3,0,2,2,0,0,0,0]，[1,2,2,0,0,0,2,2]，[1,2,2,2,2,0,0,2]，[3,0,2,2,2,2,2,2]，[3,0,0,0,2,0,2,2]，[1,0,2,2,2,0,2,2]，[1,0,0,0,2,0,2,2]，[1,0,2,0,0,2,2,0]，[3,2,0,2,2,0,0,0]，[1,0,2,2,0,2,0,0]，[3,2,2,0,2,2,0,0]，[3,2,2,2,0,0,2,0]，[1,0,0,0,0,2,0,0]，[3,0,0,0,0,2,0,0]，[3,2,0,0,0,0,2,0]，[1,0,0,2,0,2,2,2]，[1,0,0,0,0,2,0,2]，[3,0,0,0,0,2,0,2]，[1,2,0,0,0,0,2,0]，[3,0,0,2,0,2,2,2]，[3,2,2,0,2,0,0,0]，[1,0,2,0,0,0,0,2]，[1,0,2,0,2,2,0,2]，[1,2,2,0,0,0,0,2]，[3,2,2,2,2,2,2,0]，[3,2,2,2,0,2,2,0]，[1,0,0,2,2,0,2,2]，[1,0,0,0,0,2,2,0]，[3,0,0,0,0,2,2,0]，[3,2,0,0,0,0,2,2]，[3,0,0,2,0,2,2,0]，[3,2,2,0,2,0,0,2]，[1,0,0,0,0,2,2,2]，[3,0,0,0,0,2,2,2]，[1,2,0,0,0,0,2,2]，[1,2,2,0,2,0,0,2]，[1,0,0,2,0,2,2,0]，[3,0,2,0,0,0,0,2]，[3,0,0,2,2,0,2,2]，[1,2,2,2,0,2,2,0]，[3,2,2,0,0,0,0,2]，[1,2,2,2,2,2,2,0]，[3,0,2,0,2,2,0,2]，[1,0,2,2,2,0,0,0]，[3,2,0,2,0,0,0,0]，[1,0,2,2,0,0,2,0]，[1,2,2,2,0,0,0,2]，[1,2,2,2,0,0,0,0]，[3,2,0,2,0,2,2,2]，[1,0,2,0,0,2,0,2]，[3,0,2,2,2,0,2,2]，[3,0,2,0,0,2,2,0]，[1,2,2,2,0,0,2,0]，[1,2,2,0,2,2,0,0]，[3,0,2,2,0,2,0,0]，[1,2,0,2,2,0,0,0]，[1,0,0,0,2,2,2,0]，[3,0,0,2,0,0,0,0]，[3,2,2,2,2,0,0,2]，[1,0,2,2,2,2,2,2]，[1,2,0,0,0,2,2,2]，[3,2,2,0,0,0,2,2]，[1,0,2,2,0,0,0,0]，[3,2,2,0,2,2,2,0]，[3,2,0,0,2,2,2,2]，[3,2,0,2,0,0,2,0]，[3,2,2,2,0,2,0,0]，[1,0,0,0,2,2,0,2]，[3,0,2,2,0,2,2,2]，[3,2,2,2,0,2,0,2]，[3,2,0,0,2,0,2,2]，[1,0,2,2,2,2,2,0]，[1,0,2,0,0,2,2,2]，[1,2,0,2,2,0,2,0]，[3,2,0,0,2,2,2,0]，[1,0,2,2,0,0,0,2]，[3,0,2,2,0,0,2,2]，[1,2,0,0,0,2,0,0]，[1,0,0,2,2,2,2,0]，[1,2,0,2,2,2,0,2]，[1,2,2,2,2,2,0,0]，[1,0,2,0,2,2,2,0]，[3,0,2,0,2,0,0,0]，[1,2,0,0,2,0,2,0]，[1,2,0,2,0,0,0,2]，[3,2,0,2,2,2,0,0]，[1,2,0,2,2,0,2,2]，[1,2,0,2,2,2,2,2]，[3,0,2,0,0,0,2,0]，[1,0,0,2,2,0,0,0]，[3,0,0,2,2,0,0,2]，[1,0,2,0,0,0,2,2]，[1,2,2,0,2,2,2,2]，[3,2,0,0,2,0,0,0]，[3,0,2,2,0,2,2,0]，[1,2,0,0,0,2,2,0]，[1,0,2,2,2,0,0,2]，[1,2,0,0,2,2,0,2]，[3,0,2,2,2,2,0,0]，[1,2,0,0,0,2,0,2]，[1,2,0,2,2,2,0,0]，[3,2,0,2,0,0,2,2]，[3,0,2,0,0,2,0,0]，[1,0,2,2,2,2,0,0]，[1,2,2,0,2,2,0,2]，[3,0,2,0,2,2,2,0]，[3,0,0,2,2,2,2,2]，[1,2,2,2,2,0,2,2]，[3,2,0,0,0,2,2,0]，[1,2,2,0,0,2,2,0]，[3,2,2,0,0,2,0,2]，[3,2,2,0,0,2,0,0]，[1,2,2,2,2,0,2,0]，[1,0,0,0,2,2,0,0]，[1,0,2,0,0,0,2,0]，[3,0,0,2,2,0,0,0]，[3,2,0,2,2,0,0,2]，[3,0,0,0,2,0,0,0]，[3,2,2,0,0,2,2,0]，[3,2,2,2,2,2,0,0]，[3,2,2,2,2,0,0,0]，[1,0,0,0,2,0,0,0]，[3,2,0,0,2,0,0,2]，[1,0,2,0,2,0,0,0]，[1,0,0,2,0,0,0,2]，[1,0,2,0,2,2,2,2]，[1,0,2,0,0,2,0,0]，[1,0,0,2,2,2,2,2]，[3,0,0,2,2,2,2,0]，[1,2,2,0,0,2,2,2]，[1,0,0,0,2,0,2,0]，[3,0,2,2,0,0,0,2]，[3,2,0,0,2,2,0,0]，[1,0,2,2,0,2,0,2]，[3,0,0,0,2,0,2,0]，[1,2,2,2,0,0,2,2]，[3,2,0,2,2,0,2,2]，[3,0,0,2,0,0,2,2]，[1,0,2,2,2,0,2,0]，[3,2,0,0,2,2,0,2]，[1,0,0,2,0,0,2,0]，[1,2,0,0,2,2,0,0]，[1,0,0,0,2,2,2,2]，[1,2,0,0,2,0,0,2]，[3,2,2,0,0,2,2,2]，[3,0,0,0,2,0,0,2]，[1,0,0,0,2,0,0,2]，[1,0,0,2,0,0,2,2]，[3,2,0,0,0,2,0,0]，[1,2,2,0,0,0,2,0]，[3,0,2,0,2,2,2,2]，[1,2,2,2,2,2,0,2]，[3,2,2,0,2,2,0,2]，[3,2,0,0,0,2,0,2],[3,0,0,2,0,0,2,0],[3,2,2,0,0,0,2,0],[1,0,0,2,2,0,0,2],[3,2,2,2,2,2,0,2],[1,0,0,2,2,2,0,2],[3,0,2,2,2,0,0,2],[3,0,0,2,2,2,0,2],[1,2,2,2,2,0,0,0],[3,0,2,2,0,2,0,2],[3,0,2,2,2,0,2,0 [3,0,0,0,2,2,2,2], [1,2,0,2,0,2,2,0], [3,2,0,0,2,0,2,0], [1,2,0,2,2,0,0,2], [3,0,0,0,2,2,0,0], [3,2,2,0,2,2,2,2], [3,0,2,0,2,0,0,2], [1,0,2,0,2,0,0,2], [3,2,0,2,0,2,2,0], [3,0,0,2,0,0,0,2], [3,0,2,0,0,0,2,2],[3,2,0,2,0,0,0,2],[1,2,0,2,0,0,2,2],[1,2,0,0,2,2,2,0],[3,2,2,2,0,0,2,2],[1,0,2,2,0,0,2,2],[1,0,2,2,0,2,2,0],[3,2,0,2,2,2,0,2],[1,2,0,0,2,0,0,0],[3,2,0,2,2,2,2,2],[ [1,2,2,0,0,2,0,2], [1,2,2,0,0,2,0,0], [3,2,2,2,2,0,2,2], [3,2,2,2,2,0,2,0], [3,2,0,2,2,2,2,0], [3,0,2,2,2,2,0,2], [1,2,0,2,2,2,2,0], [1,0,2,2,2,2,0,2], [3,2,0,2,0,2,0,0], or, [1,2,2,0,2,0,0,2].

[0124] In Examples 1 and 2, the cross-correlation values ​​of the sequences corresponding to any two initial values ​​in the initial value set are close. Therefore, any initial value can be randomly selected from this initial value set as the initial value of the second sequence. For example, if the length of the second sequence is 127, an initial value can be randomly selected from initial value set 1. If the length of the second sequence is 255, an initial value can be randomly selected from initial value set 2.

[0125] The initial value sets in Examples 1 and 2 are merely examples. This application does not impose any restrictions on the primitive polynomial of the second sequence or on the recursive relation of the second sequence.

[0126] The initial value and cyclic shift value 'c' of the second sequence can be mapped to the first cell identifier. This can be understood as one first cell identifier corresponding to one initial value and one 'c', and a second sequence can be determined based on this initial value and 'c'. For example, if the length of the second sequence L = 127, and the number of first cell identifiers is 378 (e.g., the set of values ​​for the first cell identifiers is {0, 1, 2, ..., 378}), then the initial value set can include 6 initial values, each corresponding to 63 cyclic shift values. These 6 initial values ​​and 63 cyclic shift values ​​correspond to a total of 378 possible combinations, with each combination corresponding to one first cell identifier. That is, one second sequence is associated with one first cell identifier, and one first sequence is associated with one first cell identifier. As another example, if the number of first cell identifiers is 2016 (e.g., the set of values ​​for the first cell identifiers is {0, 1, 2, ..., 2016}), the initial value set can include 32 initial values, each corresponding to 63 cyclic shift values. The 32 initial values ​​and 63 cyclic shift values ​​correspond to a total of 2016 possible combinations, and each combination corresponds to a first cell identifier.

[0127] In one implementation, before sending the secondary synchronization signal, the network device can determine the first sequence based on the second sequence. For example, the network device can determine the initial value and c of the second sequence based on the first cell identifier, thereby determining the second sequence based on the initial value and c, and then determining the first sequence based on the second sequence. Alternatively, the network device includes a first sequence set, which comprises multiple sequences, each sequence in the first sequence set corresponding to a value of the first cell identifier. The network device can determine the second sequence from the first sequence set based on the first cell identifier.

[0128] In another implementation, the network device can directly determine the first sequence before sending the secondary synchronization signal. For example, the network device includes a second sequence set, which contains multiple first sequences. Each first sequence in the second sequence set corresponds to a value of a first cell identifier. The network device can determine the first sequence from the second sequence set based on the first cell identifier.

[0129] Combining with the previous implementation method one, the first sequence can be the sequence obtained by the network device modulating the second sequence, and the auxiliary synchronization signal is the signal obtained by the second sequence through modulation, conversion precoding, frequency domain mapping and N-point fast Fourier transform. The waveform of the auxiliary synchronization signal is a single-carrier waveform.

[0130] For example, as shown in Figure 5, the process of determining the secondary synchronization signal may include the following steps:

[0131] The second sequence is modulated to obtain the first sequence, and the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy:

[0132] or Where m = (n + c) mod L.

[0133] Based on the preceding description, if the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy formula (4), then element 0 in the second sequence can be mapped to A, element 1 in the second sequence can be mapped to A×j, element 2 in the second sequence can be mapped to -A, and element 3 in the second sequence can be mapped to -A×j. The elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy Table 1.

[0134] Table 1

[0135] Referring to Table 1, taking A=1 as an example, if A in Table 1 is replaced with 1, it can be shown in Table 2.

[0136] Table 2

[0137] Based on the preceding description, if the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy formula (5), then element 0 in the second sequence can be mapped to A, element 1 in the second sequence can be mapped to -A×j, element 2 in the second sequence can be mapped to -A, and element 3 in the second sequence can be mapped to A×j. The elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy Table 3.

[0138] Table 3

[0139] Referring to Table 3, taking A=1 as an example, if A in Table 3 is replaced with 1, it can be shown in Table 4.

[0140] Table 4

[0141] Furthermore, the second sequence is pre-coded to obtain the first frequency domain signal. For example, the second sequence can be subjected to an L-point Discrete Fourier Transform (DFT) to obtain the first frequency domain signal {X(0), X(1), ..., X(L-1)}. L is the number of DFT points, x(i) is the element of the first sequence, and X(n) is the frequency domain signal obtained after the DFT.

[0142] Furthermore, the first frequency domain signal is mapped onto L subcarriers and subjected to an N-point inverse fast fourier transformation (IFFT) to obtain the auxiliary synchronization signal, such as the auxiliary synchronization signal. N is the number of sampling points for the IFFT. The waveform of the secondary synchronization signal obtained at this time is a single-carrier waveform. Here, N is an integer greater than L, and N can be determined based on the system bandwidth. It is important to understand that the value of N is generally much larger than L.

[0143] The above are just examples. Network devices can also obtain the first sequence, for example, by storing the first sequence in the network device. The network device can convert and precode the first sequence to obtain the first frequency domain signal, and then generate the auxiliary synchronization signal based on the first frequency domain signal. Alternatively, the network device can obtain the first frequency domain signal, for example, by storing the first frequency domain signal in the network device, and then generate the auxiliary synchronization signal based on the first frequency domain signal.

[0144] In one implementation, if multiple antennas transmit auxiliary synchronization signals, the first frequency domain signal can be multiplied by a precoding matrix before subcarrier mapping. The precoding matrix is ​​preset or predefined.

[0145] Step 402: The network device sends a secondary synchronization signal.

[0146] Correspondingly, the terminal device receives the auxiliary synchronization signal from the network device.

[0147] In one implementation, the network device can also add a CP to the auxiliary synchronization signal and perform digital-to-analog conversion on the CP-added auxiliary synchronization signal to obtain an analog signal, which the network device then transmits via an antenna.

[0148] Step 403: The terminal device detects the auxiliary synchronization signal.

[0149] After receiving the auxiliary synchronization signal, the terminal device performs correlation detection on the auxiliary synchronization signal to determine the first sequence.

[0150] During the detection of the secondary synchronization signal by the terminal device, correlation processing is performed on the secondary synchronization signal and at least one specific sequence to obtain the correlation value corresponding to each specific sequence. This correlation value can refer to the cross-correlation value. The specific sequence with the largest correlation value corresponds to the secondary synchronization signal. These specific sequences can be pre-stored in the terminal device or generated by the terminal device. The terminal device can store or generate multiple specific sequences.

[0151] This application does not limit how the correlation value between two sequences is specifically determined. For example, the cross-correlation value c between frequency domain sequences S1 and S2... max (S1,S2) satisfy:

[0152] After normalization, c max (S1,S2) satisfy:

[0153] The terminal device can determine the relevant value corresponding to each specific sequence according to the above formula; the specific process will not be elaborated here.

[0154] A specific sequence can be implemented in multiple ways, and the detection method for the auxiliary synchronization signal also varies depending on the implementation method. Several examples are given below. Based on the preceding description, several possible detection methods for the auxiliary synchronization signal are presented below.

[0155] Method 1: The specific sequence is the second sequence. The terminal device acquires the second sequence and detects the auxiliary synchronization signal based on the second sequence.

[0156] The second sequence can be obtained by cyclically shifting the initial value and can be stored locally. At least one second sequence can be stored, and when detecting the secondary synchronization signal, the second sequence can be retrieved from the stored at least one second sequence. Alternatively, a set of initial values ​​can be stored locally, and when detecting the secondary synchronization signal, an initial value can be selected from the set and cyclically shifted to generate the second sequence.

[0157] The terminal device detects the auxiliary synchronization signal based on the second sequence, including: the terminal device performs correlation processing on the received auxiliary synchronization signal according to the second sequence to detect the auxiliary synchronization signal. For example, for each acquired second sequence, the terminal device can generate a first sequence based on the second sequence, obtaining multiple first sequences. The terminal device then performs correlation processing on each of the multiple first sequences with the auxiliary synchronization signal to obtain a correlation value corresponding to each first sequence. The first sequence with the largest correlation value is the first sequence corresponding to the auxiliary synchronization signal; that is, the terminal device determines the first sequence with the largest correlation value as the auxiliary synchronization sequence corresponding to the auxiliary synchronization signal.

[0158] Method 2: The specific sequence is the second sequence. The terminal device obtains the second sequence, generates the first sequence based on the second sequence, and detects the auxiliary synchronization signal based on the first sequence.

[0159] The second sequence can be obtained by cyclically shifting the initial value and can be stored locally. At least one second sequence can be stored, and when detecting the secondary synchronization signal, the second sequence can be retrieved from the stored at least one second sequence. Alternatively, a set of initial values ​​can be stored locally, and when detecting the secondary synchronization signal, an initial value can be selected from the set and cyclically shifted to generate the second sequence.

[0160] The terminal device detects the auxiliary synchronization signal based on the second sequence, including: generating a first sequence based on the second sequence, and performing correlation processing on the received auxiliary synchronization signal based on the first sequence to detect the auxiliary synchronization signal. For example, for each acquired second sequence, the terminal device can generate a first sequence based on the second sequence, obtaining multiple first sequences. The terminal device then performs correlation processing on each of the multiple first sequences with the auxiliary synchronization signal to obtain a correlation value corresponding to each first sequence. The first sequence with the largest correlation value is the first sequence corresponding to the auxiliary synchronization signal; that is, the terminal device determines the first sequence with the largest correlation value as the auxiliary synchronization sequence corresponding to the auxiliary synchronization signal.

[0161] Method 3: The specific sequence is the first sequence. The first sequence is obtained, and the terminal device detects the auxiliary synchronization signal based on the first sequence.

[0162] The first sequence is generated based on the second sequence and can be stored locally. At least one first sequence can be stored; when detecting the secondary synchronization signal, the first sequence can be retrieved from the stored at least one first sequence. Alternatively, at least one second sequence can be stored; when detecting the secondary synchronization signal, a second sequence can be selected from the stored at least one second sequence, and the first sequence can be generated based on the selected second sequence. Alternatively, an initial value set can be stored; when detecting the secondary synchronization signal, an initial value can be selected from the initial value set, cyclically shifted to generate the second sequence, and then the first sequence can be generated based on the first sequence.

[0163] The terminal device detects the auxiliary synchronization signal based on the first sequence by performing correlation processing on the received auxiliary synchronization signal according to the first sequence to detect the auxiliary synchronization signal. For example, the terminal device performs correlation processing on multiple first sequences with the auxiliary synchronization signal respectively to obtain a correlation value corresponding to each first sequence. The first sequence with the largest correlation value is the first sequence corresponding to the auxiliary synchronization signal, that is, the terminal device determines the first sequence with the largest correlation value as the auxiliary synchronization sequence corresponding to the auxiliary synchronization signal.

[0164] Method 4: The specific sequence is a synchronization sequence, and the terminal device detects the auxiliary synchronization signal based on the set of synchronization sequences.

[0165] The auxiliary synchronization sequence set includes at least one first sequence, which is a sequence derived from a second sequence. At least one auxiliary synchronization sequence set can be stored; when detecting an auxiliary synchronization signal, a sequence can be selected from the stored auxiliary synchronization sequence set for detection. Alternatively, at least one second sequence can be stored; when detecting an auxiliary synchronization signal, a second sequence can be selected from the stored at least one second sequence, and a first sequence can be generated based on the selected second sequence. Thus, by traversing the stored second sequences, at least one first sequence can be generated, obtaining the auxiliary synchronization sequence set.

[0166] When a terminal device detects a secondary synchronization signal, it can sequentially perform inner product operations with all sequences in the secondary synchronization sequence set and the received secondary synchronization signal to obtain a correlation value set. A correlation value in the correlation value set corresponds to a sequence in the secondary synchronization sequence set. The secondary synchronization signal is determined based on the maximum correlation value in the correlation value set. For example, the terminal device can determine the secondary synchronization sequence corresponding to the maximum correlation value in the correlation value set as the secondary synchronization sequence corresponding to the secondary synchronization signal; that is, the second sequence with the largest correlation value is the second sequence corresponding to this secondary synchronization signal.

[0167] The above are just examples. There may be other ways for the terminal device to detect the auxiliary synchronization signal, and this application does not limit this.

[0168] The terminal device can also determine the first cell identifier based on the first sequence with the largest correlation value (i.e., the first sequence corresponding to the secondary synchronization signal), and the specific process will not be described in detail.

[0169] The method provided in this application provides that the first sequence is a Z4 sequence, which has low cross-correlation after modulation. The cyclic shift set composed of cyclic shifts can carry more cell identifiers, and the waveform of the auxiliary synchronization signal is a single-carrier waveform. The PAPR performance of the auxiliary synchronization signal can be improved by 4dB, which can reduce the PAPR of the auxiliary synchronization signal and improve the coverage of the auxiliary synchronization signal.

[0170] Figure 6 shows a flowchart of a communication method provided in an embodiment of this application. The method includes:

[0171] Step 601: The network device generates a secondary synchronization signal.

[0172] The secondary synchronization signal is derived from the first sequence, which can be called the secondary synchronization signal sequence. The secondary synchronization signal can be used to determine the physical cell identifier, for example, based on... and The physical cell identifier can be determined, and the secondary synchronization signal can carry... It can be determined based on the primary synchronization signal. For example, the physical cell identifier may be carried solely by the secondary synchronization signal. This application does not limit the specific method by which the secondary synchronization signal carries the physical cell identifier. It can also be called the first community identifier. It should be understood that the first community identifier can also be the physical community identifier.

[0173] In this application, the first sequence is the gold sequence. The specific method for determining the first sequence is not limited in this application. For example, the first sequence can be determined based on the third and fourth sequences, where the lengths of the first, third, and fourth sequences are all L. The elements e(k) of the third sequence, f(m) of the fourth sequence, and x(n) of the first sequence satisfy: x(n) = mod(e(k) + f(m), 2), where k = (n + c1) mod L, m = (n + c2) mod L, c1 and c2 are integers, and 0 ≤ n. <L,0≤m<L,0≤k<L;

[0174] Wherein, c1 is p1 × ID1, ID1 ranges from [0, K1-1], K1 is a positive integer; c2 is p2 × ID2, ID2 ranges from [0, K2-1], K1 and K2 are positive integers; the ratio of p1 to L is greater than a first threshold; the ratio of p2 to L is greater than a second threshold. The third and fourth sequences can be m sequences.

[0175] Where c1 is p1 × ID1, ID1 takes values ​​in the range [0, K1-1], where K1 is a positive integer; c2 is p2 × ID2, ID2 takes values ​​in the range [0, K2-1], where K1 and K2 are positive integers. c1 can refer to the cyclic shift value of the third sequence, and p1 can refer to the cyclic shift interval of the third sequence; c2 can refer to the cyclic shift value of the fourth sequence, and p2 can refer to the cyclic shift interval of the fourth sequence.

[0176] In this implementation, by increasing the cyclic shift interval, the impact of residual error in the detection of the main synchronization signal on the auxiliary synchronization signal can be reduced, thereby increasing the success rate of the auxiliary synchronization signal detection.

[0177] The value ranges of L, c1, c2, ID1, and ID2 can be preset or predefined. ID1 and ID2 can be used to determine the physical cell identifier. For example, there is a mapping relationship between ID1, ID2, and the physical cell identifier. This mapping relationship is preset, such as the mapping relationship being first cell identifier = K2*ID1+ID2 or first cell identifier = K1*ID2+ID1.

[0178] Optionally, p1 = floor(L / K1), or p1 = ceil(L / K1); or p1 = round(L / K1). The value of p1 can also be preset or predefined. p2 = floor(L / K2), or p2 = ceil(L / K2); or p2 = round(L / K2). The value of p2 can also be preset or predefined. In this implementation, the above-mentioned values ​​of p1 and p2 can maximize the minimum interval between the two cyclic shift values, ensuring the lowest cross-correlation between sequences.

[0179] In one possible implementation, the ratio of p1 to L is greater than a first threshold, and the ratio of p2 to L is greater than a second threshold. The first threshold can be equal to the second threshold, or the absolute value of the difference between the first and second thresholds can be equal to a third threshold. In this implementation, by increasing the cyclic shift interval, the impact of residual errors in the detection of the primary synchronization signal on the secondary synchronization signal can be reduced, thereby increasing the success rate of the secondary synchronization signal detection.

[0180] In one possible implementation, the difference between p1 and p2 is less than a third threshold, or the absolute value of the difference between p1 and p2 is less than the third threshold. For example, the third threshold is less than or equal to 4. This method maximizes the guarantee that the cyclic shifts of the second and third sequences are as large as possible the ratio of CP to OFDM symbols, thereby improving the detection efficiency of the auxiliary synchronization signal determined based on the first sequence.

[0181] For example, the cyclic shift intervals of the third and fourth sequences are both 1, and the cyclic shift values ​​of the third and fourth sequences are c1=1 and c2=5, respectively. If the cyclic shift offset corresponding to the residual error detected by PSS is 1, then the receiver on the receiving side will misdetect the cyclic shift values ​​of the third and fourth sequences as 2 and 6, respectively, resulting in detection failure. In this application, by increasing the cyclic shift interval, for example, the cyclic shift intervals of the third sequence and the fourth sequence are p1=7 and p2=7 respectively, the cyclic shift value of the third sequence can be 0, 7, 14, 21, etc., and the cyclic shift value of the fourth sequence can be 0, 7, 14, 21, etc. If the cyclic shift values ​​of the third sequence and the fourth sequence are c1=7 and c2=7 respectively, and the cyclic shift offset corresponding to the residual error of PSS detection is 1, then the receiver on the receiving side will misdetect the cyclic shift values ​​of the third sequence and the fourth sequence as 8 and 8 respectively. However, since there is no cyclic shift value of 8 in the third sequence and the fourth sequence, the receiving side considers the actual cyclic shift value to be the value closest to 8, that is, determines the cyclic shift value to be 7, thereby successfully detecting the auxiliary synchronization signal.

[0182] In one implementation, the network device can determine the first sequence based on the third and fourth sequences before sending the secondary synchronization signal. In another implementation, the network device can directly determine the first sequence before sending the secondary synchronization signal. For example, the network device includes a second sequence set, which contains multiple first sequences. Each first sequence in the second sequence set corresponds to a value of a first cell identifier, and the network device can determine the first sequence from the second sequence set based on the first cell identifier.

[0183] This application does not limit how the third and fourth sequences are determined. In one implementation, the third sequence can be a sequence from a set of third sequences, which is preset and includes at least one sequence. Similarly, the fourth sequence can be a sequence from a set of fourth sequences, which is preset and includes at least one sequence. In this implementation, the network device can determine the values ​​of ID1 and ID2 based on the physical cell identifier, and determine c1 = p1 × ID1 based on the value of ID1, and c2 = p2 × ID2 based on the value of ID2; the network device can select a sequence from the set of third sequences as the third sequence based on the first cell identifier, and select a sequence from the set of fourth sequences as the fourth sequence based on the first cell identifier; the network device can determine the first sequence based on the cyclic shift value c1, the third sequence, the cyclic shift value c2, and the fourth sequence.

[0184] In one implementation, the third sequence can also be determined based on the first primitive polynomial, which is a preset. The fourth sequence can also be determined based on the second primitive polynomial, which is a preset. For example, the recursive formula corresponding to the first primitive polynomial is e(k+7)=mod(e(k+4)+e(k),2), assuming the initial value is [e(6),e(5),e(4),e(3),e(2),e(1),e(0)]=[0,0,0,0,0,0,1]; the recursive formula corresponding to the second primitive polynomial is f(m+7)=mod(f(m+1)+e(m),2), assuming the initial value is [f(6),f(5),f(4),f(3),f(2),f(1),f(0)]=[0,0,0,0,0,0,1]. In this implementation, the network device can determine the third sequence based on the recursive formula corresponding to the first primitive polynomial and the initial value; and determine the fourth sequence based on the recursive formula corresponding to the second primitive polynomial and the initial value. The specific process will not be elaborated here.

[0185] It is important to understand that the third sequence can be a sequence in a set of third sequences, where each sequence in the set has a different recursive formula; the fourth sequence can be a sequence in a set of fourth sequences, where each sequence in the set has a different recursive formula.

[0186] Based on the preceding description, in this application, the auxiliary synchronization signal is a signal obtained by first sequence through quadrature phase shift keying (QPSK) modulation, conversion precoding, frequency domain mapping, and N-point inverse fast Fourier transform. The waveform of the auxiliary synchronization signal is a single-carrier waveform.

[0187] For example, the process of determining the secondary synchronization signal may include the following steps:

[0188] The first sequence is QPSK modulated to obtain the second sequence.

[0189] Among them, the elements s(n) of the second sequence and the elements x(n) of the first sequence satisfy Table 5, that is, the element 0 in the first sequence can be mapped to... Element 1 in the first sequence can be mapped to... Element 3 in the first sequence can be mapped to... Element 3 in the first sequence can be mapped to... For example, it can be shown in Table 5.

[0190] Table 5

[0191] The second sequence can be a phase sequence, where each element takes the value of one of the numbers {1, -1, j, -j}, where j is an imaginary number. The multiplication complexity of performing correlation detection on a phase sequence is negligible, thus reducing the detection complexity of the second sequence.

[0192] Furthermore, the second sequence is pre-coded to obtain the first frequency domain signal. For example, the second sequence can be subjected to an L-point Discrete Fourier Transform (DFT) to obtain the first frequency domain signal {X(0), X(1), ..., X(L-1)}. Further, the first frequency domain signal is mapped onto L subcarriers and subjected to an N-point IFFT to obtain the auxiliary synchronization signal, where N is the number of IFFT sampling points. The waveform of the obtained auxiliary synchronization signal is a single-carrier waveform. Here, N is an integer greater than L, and N can be determined based on the system bandwidth. It is important to understand that the value of N is generally much larger than L.

[0193] The above are just examples. Network devices can also acquire a second sequence, for example, by storing the second sequence in the network device. The network device can then convert and precode the second sequence to obtain a first frequency domain signal, and thereby generate a secondary synchronization signal based on the first frequency domain signal. Alternatively, the network device can acquire the first frequency domain signal, for example, by storing the first frequency domain signal in the network device, and thereby generate a secondary synchronization signal based on the first frequency domain signal.

[0194] In one implementation, if multiple antennas transmit auxiliary synchronization signals, the first frequency domain signal can be multiplied by a precoding matrix before subcarrier mapping. The precoding matrix is ​​preset or predefined.

[0195] Step 602: The network device sends a secondary synchronization signal.

[0196] Correspondingly, the terminal device receives the auxiliary synchronization signal from the network device.

[0197] In one implementation, the network device can also add a CP to the auxiliary synchronization signal and perform digital-to-analog conversion on the CP-added auxiliary synchronization signal to obtain an analog signal, which the network device then transmits via an antenna.

[0198] Step 603: The terminal device detects the auxiliary synchronization signal.

[0199] After receiving the auxiliary synchronization signal, the terminal device performs correlation detection on the auxiliary synchronization signal to determine the first sequence.

[0200] During the detection of the secondary synchronization signal by the terminal device, correlation processing is performed on the secondary synchronization signal and at least one specific sequence to obtain the correlation value corresponding to each specific sequence. This correlation value can refer to the cross-correlation value. The specific sequence with the largest correlation value is the sequence corresponding to the secondary synchronization signal. These specific sequences can be pre-stored in the terminal device or generated by the terminal device. The terminal device can store or generate multiple specific sequences. For details on how to determine the correlation value between two sequences, please refer to the preceding description; it will not be repeated here.

[0201] A specific sequence can be implemented in multiple ways, and the detection method for the auxiliary synchronization signal also varies depending on the implementation method. Several examples are given below. Based on the preceding description, several possible detection methods for the auxiliary synchronization signal are presented below.

[0202] In Method 1, the specific sequences are the third and fourth sequences. The terminal device acquires the third and fourth sequences and detects the auxiliary synchronization signal based on the third and fourth sequences.

[0203] The terminal device stores at least one third sequence and at least one fourth sequence. When detecting the auxiliary synchronization signal, it can obtain the third sequence from at least one third sequence and the fourth sequence from at least one fifth sequence. Alternatively, the terminal device can determine at least one third sequence based on the recursive formula corresponding to the first primitive polynomial and the initial value, and determine at least one fourth sequence based on the recursive formula corresponding to the second primitive polynomial and the initial value.

[0204] The terminal device detects the auxiliary synchronization signal based on a third sequence and a fourth sequence, including: the terminal device performs correlation processing on the received auxiliary synchronization signal according to the third sequence and the fourth sequence to detect the auxiliary synchronization signal. For example, a first sequence is generated for each acquired third sequence and each fourth sequence, and a second sequence is determined based on the first sequence. The terminal device can generate multiple first sequences, thereby obtaining multiple second sequences. The terminal device performs correlation processing on the multiple second sequences with the auxiliary synchronization signal respectively to obtain a correlation value corresponding to each second sequence. The second sequence with the largest correlation value is the second sequence corresponding to the auxiliary synchronization signal, that is, the terminal device determines the second sequence with the largest correlation value as the auxiliary synchronization sequence corresponding to the auxiliary synchronization signal.

[0205] Method 2: The specific sequence is the first sequence. The terminal device acquires the first sequence and detects the auxiliary synchronization signal based on the first sequence.

[0206] The first sequence can be determined based on the third and fourth sequences and can be stored locally. At least one first sequence can be stored, and when detecting the secondary synchronization signal, the first sequence can be obtained from the stored at least one first sequence. Alternatively, at least one third sequence and at least one fourth sequence can be stored locally, and when detecting the secondary synchronization signal, the third sequence is obtained from the at least one third sequence, the fourth sequence is obtained from the at least one fourth sequence, and the first sequence is generated based on the third and fourth sequences.

[0207] The terminal device detects the secondary synchronization signal based on the first sequence by performing correlation processing on the received signal according to the first sequence to detect the synchronization signal. For example, for each acquired first sequence, the terminal device can generate a second sequence, obtaining multiple second sequences. The terminal device then performs correlation processing on each of the multiple second sequences with the secondary synchronization signal to obtain a correlation value corresponding to each second sequence. The correlation processing includes correlation calculation, and the second sequence with the largest correlation value is the second sequence corresponding to the secondary synchronization signal. That is, the terminal device determines the second sequence with the largest correlation value as the secondary synchronization sequence corresponding to the secondary synchronization signal.

[0208] Method 3: The specific sequence is the first sequence. The terminal device acquires the first sequence, determines the second sequence based on the first sequence, and then detects the auxiliary synchronization signal based on the second sequence. The second sequence is generated based on the first sequence.

[0209] For example, the first sequence can be determined based on the third and fourth sequences and can be stored locally. At least one first sequence can be stored, and when detecting the secondary synchronization signal, the first sequence can be obtained from the stored at least one first sequence. Alternatively, at least one third sequence and at least one fourth sequence can be stored locally, and when detecting the secondary synchronization signal, the third sequence is obtained from the at least one third sequence, the fourth sequence is obtained from the at least one fourth sequence, and the first sequence is generated based on the third and fourth sequences.

[0210] The terminal device detects the auxiliary synchronization signal based on the second sequence, including: the terminal device generating a second sequence based on the first sequence, and performing correlation processing on the received signal based on the second sequence. For example, for each acquired first sequence, the terminal device can generate a second sequence, obtaining multiple second sequences. The terminal device then performs correlation processing on each of the multiple second sequences with the auxiliary synchronization signal to obtain a correlation value corresponding to each second sequence. The second sequence with the largest correlation value is the second sequence corresponding to the auxiliary synchronization signal; that is, the terminal device determines the second sequence with the largest correlation value as the auxiliary synchronization sequence corresponding to the auxiliary synchronization signal.

[0211] Method 4: The specific sequence is the second sequence. The second sequence is obtained, and the terminal device detects the auxiliary synchronization signal based on the second sequence.

[0212] The second sequence is generated based on the first sequence and can be stored locally. At least one second sequence can be stored, and when detecting the secondary synchronization signal, the second sequence can be retrieved from the stored at least one second sequence. Alternatively, at least one first sequence can be stored, and when detecting the secondary synchronization signal, a first sequence can be selected from the stored at least one first sequence, and the second sequence can be generated based on the selected first sequence. Alternatively, at least one third sequence and at least one fourth sequence can be stored locally, and when detecting the secondary synchronization signal, the third sequence is retrieved from the at least one third sequence, the fourth sequence is retrieved from the at least one fourth sequence, the first sequence is generated based on the third and fourth sequences, and then the second sequence is generated based on the first sequence.

[0213] The terminal device detects the auxiliary synchronization signal based on the second sequence, including: the terminal device generating a second sequence based on the first sequence, and performing correlation processing on the received signal based on the second sequence. For example, for each acquired first sequence, the terminal device can generate a second sequence, obtaining multiple second sequences. The terminal device then performs correlation processing on each of the multiple second sequences with the auxiliary synchronization signal to obtain a correlation value corresponding to each second sequence. The second sequence with the largest correlation value is the second sequence corresponding to the auxiliary synchronization signal; that is, the terminal device determines the second sequence with the largest correlation value as the auxiliary synchronization sequence corresponding to the auxiliary synchronization signal.

[0214] Method 5: The specific sequence is a secondary synchronization sequence, and the terminal device detects the secondary synchronization signal based on the sequence in the set of secondary synchronization sequences.

[0215] The auxiliary synchronization sequence set includes at least one second sequence, which is a sequence obtained based on the first sequence. At least one auxiliary synchronization sequence set can be stored. When detecting an auxiliary synchronization signal, a sequence can be selected from the stored auxiliary synchronization sequence set for detection. Alternatively, at least one first sequence can be stored. When detecting an auxiliary synchronization signal, a first sequence can be selected from the stored at least one first sequence, and a second sequence can be generated based on the selected first sequence. Thus, by traversing the stored first sequences, at least one second sequence can be generated, obtaining the auxiliary synchronization sequence set. Alternatively, at least one third sequence and at least one fourth sequence can be stored locally. When detecting an auxiliary synchronization signal, a third sequence is obtained from the at least one third sequence, a fourth sequence is obtained from the at least one fourth sequence, a first sequence is generated based on the third and fourth sequences, and then a second sequence is generated based on the first sequence. Thus, by traversing the stored at least one third sequence and at least one fourth sequence, at least one second sequence can be generated, obtaining the auxiliary synchronization sequence set.

[0216] When a terminal device detects a secondary synchronization signal, it can sequentially perform inner product operations with all sequences in the secondary synchronization sequence set and the received secondary synchronization signal to obtain a correlation value set. A correlation value in the correlation value set corresponds to a sequence in the secondary synchronization sequence set. The secondary synchronization signal is determined based on the maximum correlation value in the correlation value set. For example, the terminal device can determine the secondary synchronization sequence corresponding to the maximum correlation value in the correlation value set as the secondary synchronization sequence corresponding to the secondary synchronization signal; that is, the second sequence with the largest correlation value is the second sequence corresponding to this secondary synchronization signal.

[0217] The above are just examples. There may be other ways for the terminal device to detect the auxiliary synchronization signal, and this application does not limit this.

[0218] The terminal device can also determine the first cell identifier based on the second sequence with the largest correlation value (i.e., the second sequence corresponding to the auxiliary synchronization signal). The specific process will not be described in detail here.

[0219] The method provided in this application modulates the auxiliary synchronization signal obtained based on the first sequence as QPSK, and the waveform of the auxiliary synchronization signal is a single-carrier waveform. The PAPR performance of the auxiliary synchronization signal can be improved by 4dB, which can reduce the PAPR of the auxiliary synchronization signal and improve the coverage of the auxiliary synchronization signal.

[0220] It is understood that, in order to achieve the functions in the above embodiments, the terminal device or network device includes hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0221] The following are schematic diagrams of possible communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of terminal devices or network devices in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0222] In the case of using integrated units, FIG7 shows a possible exemplary block diagram of the communication device involved in the embodiments of this application. As shown in FIG7, the communication device 700 may include a processing unit 701 and a communication unit 702. The processing unit 701 is used to control and manage the operation of the communication device 700. The communication unit 702 is used to support communication between the communication device 700 and other devices. Optionally, the communication unit 702 may include a receiving unit and / or a transmitting unit, respectively used to perform receiving and transmitting operations. Optionally, the communication device 700 may also include a storage unit for storing the program code and / or data of the communication device 700. The communication unit may be referred to as an input / output unit, transceiver unit, etc., and the communication unit may be a transceiver; the processing unit may be a processor. When the communication device is a module (e.g., a chip) in a communication device, the communication unit may be an input / output interface, input / output circuit, or input / output pin, etc., and may also be referred to as an interface, communication interface, or interface circuit, etc.; the processing unit may be a processor, processing circuit, or logic circuit, etc. Specifically, the communication device may be the aforementioned network device, terminal, etc.

[0223] In one embodiment, the communication device 700 is used to implement the functions of a network device:

[0224] A processing unit is configured to generate a secondary synchronization signal, which is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; wherein the first sequence is determined based on a second sequence, both the first sequence and the second sequence have a length of L, and the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy:

[0225] or Where, m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; the c is p × ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer.

[0226] A communication unit, configured to send the secondary synchronization signal.

[0227] In another embodiment, the communication device 700 is configured to implement the functions of a terminal device:

[0228] A processing unit, configured to detect a secondary synchronization signal from a network device; the secondary synchronization signal is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; wherein, the first sequence is determined according to a second sequence, the lengths of the first sequence and the second sequence are both L, and the element d(m) of the second sequence and the element x(n) of the first sequence satisfy:

[0229] Or Where, m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; the c is p × ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer.

[0230] In one embodiment, the communication device 700 is configured to implement the functions of a network device:

[0231] A processing unit, configured to generate a secondary synchronization signal, the secondary synchronization signal is a signal obtained based on a first sequence; the modulation mode of the secondary synchronization signal is QPSK; the waveform of the secondary synchronization signal is a single-carrier waveform;

[0232] A communication unit, configured to send the secondary synchronization signal.

[0233] In another embodiment, the communication device 700 is configured to implement the functions of a terminal device:

[0234] A processing unit, configured to detect a secondary synchronization signal from a network device; the secondary synchronization signal is a signal obtained based on a first sequence; the modulation mode of the secondary synchronization signal is QPSK; the waveform of the secondary synchronization signal is a single-carrier waveform.

[0235] The above-mentioned processing unit and communication unit can also implement other functions. For a more detailed description, reference can be directly made to the relevant descriptions in the above method embodiments, which will not be elaborated here.

[0236] It should be understood that the division of units in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, all units in the device can be implemented entirely through software calls from processing elements; all units can be implemented entirely in hardware; or some units can be implemented through software calls from processing elements, while others are implemented in hardware. For example, each unit can be a separate processing element, or it can be integrated into a chip within the device. Alternatively, it can be stored as a program in memory, called and executed by a processing element of the device. Moreover, these units can be fully or partially integrated together, or implemented independently. The processing element here can also be called a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, the operations or units described above can be implemented through integrated logic circuits in the processor element or through software calls from processing elements.

[0237] Figure 8 is a schematic block diagram of a communication device 800 provided in an embodiment of this application. The communication device 800 can be a terminal device or a network device as described in the above embodiments. For example, the communication device 800 can be the terminal device in Figure 1 or a chip (system) within a terminal device. In this embodiment, the chip system can be composed of chips or may include chips and other discrete devices. Specific functions can be found in the descriptions of the above method embodiments. As another example, the communication device 800 can be the network device in Figure 1 or a chip (system) within a network device. In this embodiment, the chip system can be composed of chips or may include chips and other discrete devices. Specific functions can be found in the descriptions of the above method embodiments.

[0238] The communication device 800 includes one or more processors 801, used to implement or support the communication device 800 in implementing the functions of the terminal device or network device in the methods provided in the embodiments of this application. For details, please refer to the detailed description in the method examples, which will not be repeated here. The processor 801 can also be called a processing unit or processing module, and can implement certain control functions. The processor 801 can be a general-purpose processor or a dedicated processor, etc. For example, it includes: a baseband processor, a central processing unit, an application processor, a modem processor, a graphics processor, an image signal processor, a digital signal processor, a video codec processor, a controller, a memory, and / or a neural network processor, etc. The baseband processor can be used to process communication protocols and communication data. The central processing unit can be used to control the communication device 800 (e.g., a network device or a terminal device), execute software programs and / or process data. Different processors can be independent devices or integrated into one or more processors, for example, integrated on one or more application-specific integrated circuits.

[0239] In one design, processor 801 may include program 803 (sometimes also referred to as code or instructions) that can be executed on processor 801 to cause communication device 800 to perform the methods described in the embodiments below. In yet another possible design, communication device 800 includes circuitry (not shown in FIG8) for implementing the functions of the terminal device or network device in the above embodiments.

[0240] In one design, the communication device 800 may include one or more memories 802 storing a program 804 (sometimes referred to as code or instructions), which can be run on the processor 801 to cause the communication device 800 to perform the methods described in the above method embodiments.

[0241] In one design, the processor 801 and / or memory 802 may include an artificial intelligence (AI) module for implementing AI-related functions. The AI ​​module may be implemented through software, hardware, or a combination of both. For example, the AI ​​module may include a RAN intelligent controller (RIC) module. The AI ​​module may be a near real-time RIC or a non-real-time RIC.

[0242] In one possible design, the processor 801 and / or memory 802 may also store data. The processor and memory may be configured separately or integrated together.

[0243] In one possible design, the communication device 800 may further include a transceiver 805 and / or an antenna 806. The processor 801, sometimes referred to as a processing unit, controls the communication device 800. The transceiver 805, sometimes referred to as a communication unit, transceiver, transceiver circuit, or transceiver, is used to implement the transmission and reception functions of the communication device 800 through the antenna 806.

[0244] In one possible design, the communication device 800 may further include one or more of the following components: a wireless communication module, an audio module, an external memory interface, internal memory, a universal serial bus (USB) interface, a power management module, an antenna, a speaker, a microphone, an input / output module, a sensor module, a motor, a camera, or a display screen, etc. It is understood that in some embodiments, the communication device 800 may include more or fewer components, or some components may be integrated, or some components may be separated. These components may be implemented in hardware, software, or a combination of software and hardware.

[0245] The communication device in the above embodiments can be a terminal device, a circuit, a chip applied in a terminal device, or other combined devices or components having the aforementioned terminal device. Alternatively, the communication device in the above embodiments can be a network device, a circuit, a chip applied in a network device, or other combined devices or components having the aforementioned network device. When the communication device is a terminal device or a network device, the transceiver module can be a transceiver, which may include an antenna and radio frequency circuits, etc., and the processing module can be a processor, such as a CPU. When the communication device is a chip system, the communication device can be an FPGA, a dedicated ASIC, a system-on-chip (SoC), a CPU, a network processor (NP), a DSP, a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips. The processing module can be the processor of the chip system. The transceiver module or communication interface can be the input / output interface or interface circuit of the chip system. For example, the interface circuit can be a code / data read / write interface circuit. The interface circuit can be used to receive code instructions (the code instructions are stored in memory and can be read directly from memory or through other devices) and transmit them to the processor; the processor can then execute the code instructions to perform the methods described in the above method embodiments. Alternatively, the interface circuit can also be a signal transmission interface circuit between a communication processor and a transceiver.

[0246] This application also provides a communication system, which includes at least one terminal device and at least one network device. The terminal device is used to implement the functions related to the above-described communication method, and the network device is used to implement the functions related to the above-described communication method. This application also provides a computer-readable storage medium, including instructions that, when executed on a computer, cause the computer to perform the method executed by the terminal device or the network device in the above-described communication method.

[0247] This application also provides a computer program product, including computer program code, which, when executed, causes a computer to perform the method executed by the terminal device or network device in the above-described communication method.

[0248] This application provides a chip system including a processor and potentially a memory, for implementing the functions of a terminal device or network device in the aforementioned communication method. The chip system can be composed of chips or may include chips and other discrete components.

[0249] To achieve the functions of the aforementioned communication device, this application also provides a chip, including a processor, for supporting the communication device in implementing the functions involved in the terminal device or network device in the above method embodiments. In one possible design, the chip is connected to a memory or the chip includes a memory for storing necessary computer programs, instructions, and data for the communication device.

[0250] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0251] It should be noted that the structure shown in Figure 8 does not constitute a specific limitation on the terminal device or network device. For example, in other embodiments of this application, the terminal device or network device may include more or fewer components than shown in the figure, or combine some components, or split some components, or have different component arrangements. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0252] When the aforementioned communication device is a chip applied to a terminal, the terminal chip implements the functions of the terminal in the above method embodiments. The terminal chip receives information from other modules (such as radio frequency modules or antennas) in the terminal, which is information sent to the terminal by the base station; or, the terminal chip sends information to other modules (such as radio frequency modules or antennas) in the terminal, which is information sent to the base station by the terminal.

[0253] When the aforementioned communication device is a module applied to a base station, the base station module implements the functions of the base station in the above method embodiments. The base station module receives information from other modules (such as radio frequency modules or antennas) in the base station, which is information sent by the terminal to the base station; or, the base station module sends information to other modules (such as radio frequency modules or antennas) in the base station, which is information sent by the base station to the terminal.

[0254] It is understood that the processor in the embodiments of this application may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

[0255] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. Of course, the processor and storage medium can also exist as discrete components in the base station or terminal.

[0256] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0257] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0258] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0259] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0260] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0261] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method, characterized in that, including: A secondary synchronization signal is generated, which is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; wherein, the first sequence is determined based on a second sequence, and both the first sequence and the second sequence have a length of L, and the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy: or where m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; c is p×ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer; transmitting the secondary synchronization signal.

2. The method according to claim 1, characterized in that, Said generating the secondary synchronization signal includes: modulating the second sequence to obtain the first sequence; performing transform precoding on the first sequence to obtain a first frequency-domain signal; mapping the first frequency-domain signal to L subcarriers and performing N-point inverse fast Fourier transform to obtain the secondary synchronization signal, where L is an integer greater than 1.

3. The method according to claim 1 or 2, characterized in that, The ratio of p to L is greater than a first threshold.

4. The method according to claim 3, characterized in that, The first threshold is the ratio of the cyclic prefix CP length of the secondary synchronization signal to the orthogonal frequency division multiplexing OFDM symbol length.

5. The method according to any one of claims 1 to 4, characterized in that, The first sequence is a Z4 sequence.

6. A communication method, characterized in that, including: A secondary synchronization signal from a network device is detected; the secondary synchronization signal is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; wherein, the first sequence is determined based on a second sequence, both the first sequence and the second sequence have a length of L, and the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy: or where m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; c is p×ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer.

7. The method according to claim 6, characterized in that, The ratio of p to L is greater than a first threshold.

8. The method according to claim 7, characterized in that, The first threshold is the ratio of the cyclic prefix CP length of the secondary synchronization signal to the orthogonal frequency division multiplexing OFDM symbol length.

9. The method according to any one of claims 6 to 8, characterized in that, The first sequence is a Z4 sequence.

10. A communication method, characterized in that, including: generating a secondary synchronization signal, which is a signal obtained based on a first sequence; the modulation method of the secondary synchronization signal is QPSK; the waveform of the secondary synchronization signal is a single-carrier waveform; transmitting the secondary synchronization signal.

11. The method according to claim 10, characterized in that, Said generating the secondary synchronization signal includes: performing QPSK modulation on the first sequence to obtain a second sequence; performing transform precoding on the second sequence to obtain a first frequency-domain signal; mapping the first frequency-domain signal to L subcarriers and performing N-point inverse fast Fourier transform to obtain the secondary synchronization signal, where L is an integer greater than 1.

12. The method according to claim 10 or 11, characterized in that, The first sequence is determined according to a third sequence and a fourth sequence. The lengths of the first sequence, the third sequence and the fourth sequence are all L. The elements e(k) of the third sequence, the elements f(m) of the fourth sequence, and the elements x(n) of the first sequence satisfy: x(n) = mod(e(k) + f(m), 2), where k = (n + c1) mod L, m = (n + c2) mod L, c1 and c2 are integers, 0 ≤ n < L, 0 ≤ m < L, 0 ≤ k < L; where c1 is p1×ID1, the value range of ID1 is [0, K1 - 1], K1 is a positive integer, c2 is p2×ID2, the value range of ID2 is [0, K2 - 1], K1 and K2 are positive integers, the ratio of p1 to L is greater than a first threshold, the ratio of p2 to L is greater than a second threshold, and p1 and p2 are positive integers.

13. The method according to claim 12, characterized in that, The difference between p1 and p2 is less than a third threshold.

14. The method according to claim 13, characterized in that, The third threshold is less than or equal to 4.

15. The method according to any one of claims 12 to 14, characterized in that, The first threshold is the ratio of the cyclic prefix CP length of the secondary synchronization signal to the orthogonal frequency division multiplexing OFDM symbol length.

16. The method according to any one of claims 10 to 15, characterized in that, The first sequence is a Gold sequence.

17. A communication method, characterized in that, It includes: Detecting a secondary synchronization signal from a network device; the secondary synchronization signal is a signal obtained based on the first sequence; the modulation method of the secondary synchronization signal is QPSK; The waveform of the secondary synchronization signal is a single-carrier waveform.

18. The method according to claim 17, characterized in that, The first sequence is determined according to a third sequence and a fourth sequence. The lengths of the first sequence, the third sequence, and the fourth sequence are all L. The element e(k) of the third sequence, the element f(m) of the fourth sequence, and the element x(n) of the first sequence satisfy: x(n) = mod(e(k) + f(m), 2), where k = (n + c1) mod L, m = (n + c2) mod L, c1 and c2 are integers, 0 ≤ n < L, 0 ≤ m < L, 0 ≤ k < L; Where, c1 is p1 × ID1, the value range of ID1 is [0, K1 - 1], K1 is a positive integer, c2 is p2 × ID2, the value range of ID2 is [0, K2 - 1], K1 and K2 are positive integers, the ratio of p1 to L is greater than a first threshold, the ratio of p2 to L is greater than a second threshold, and p1 and p2 are positive integers.

19. The method according to claim 18, characterized in that, The difference between p1 and p2 is less than a third threshold.

20. The method according to claim 19, characterized in that, The third threshold is less than or equal to 4.

21. The method according to any one of claims 18 to 20, characterized in that, The first threshold is the ratio of the cyclic prefix CP length of the secondary synchronization signal to the length of the orthogonal frequency division multiplexing OFDM symbol.

22. The method according to any one of claims 18 to 21, characterized in that, The first sequence is a Gold sequence.

23. A communication device, characterized in that, It includes: A processing unit is configured to generate a secondary synchronization signal, which is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; wherein the first sequence is determined based on a second sequence, both the first sequence and the second sequence have a length of L, and the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy: or Where, m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; c is p × ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer; A communication unit for transmitting the secondary synchronization signal.

24. A communication device, characterized in that, It includes: A processing unit is configured to detect a secondary synchronization signal from a network device; the secondary synchronization signal is a signal obtained based on a first sequence; the waveform of the secondary synchronization signal is a single-carrier waveform; wherein the first sequence is determined based on a second sequence, both the first sequence and the second sequence have a length of L, and the elements d(m) of the second sequence and the elements x(n) of the first sequence satisfy: or Where, m = (n + c) mod L, c is an integer, A is a constant, 0 ≤ n < L, 0 ≤ m < L, d(m) = 0, 1, 2 or 3; c is p × ID, the value range of ID is [0, K - 1], K is a positive integer; p is a positive integer.

25. A communication device, characterized in that, It includes: A processing unit for generating a secondary synchronization signal, the secondary synchronization signal is a signal obtained based on the first sequence; the modulation method of the secondary synchronization signal is QPSK; the waveform of the secondary synchronization signal is a single-carrier waveform; A communication unit for transmitting the secondary synchronization signal.

26. A communication device, characterized in that, It includes: A processing unit for detecting a secondary synchronization signal from a network device; the secondary synchronization signal is a signal obtained based on the first sequence; the modulation method of the secondary synchronization signal is QPSK; the waveform of the secondary synchronization signal is a single-carrier waveform.

27. A communication device, characterized in that, It includes a processor; the processor is used to execute a computer program or instruction, so that the communication device implements the method described in any one of claims 1 to 22.

28. A computer-readable storage medium, characterized in that, A computer program or instruction is stored. When the computer program or instruction runs on a computer, the computer implements the method described in any one of claims 1 to 22.

29. A computer program product, characterized in that, When a computer reads and executes the computer program product, the method described in any one of claims 1 to 22 is executed.

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