Communication method and apparatus

Abstract

The present application relates to the technical field of communications. Provided are a communication method and apparatus. The method comprises: a first communication apparatus receiving a synchronization signal, wherein the synchronization signal comprises a plurality of downlink synchronization signals from a plurality of second communication apparatuses, the downlink synchronization signals correspond to the second communication apparatuses on a one-to-one basis, the downlink synchronization signals are related to the cell radii of cells managed by the second communication apparatuses, and downlink synchronization signals of at least two different waveforms correspond to cells of different cell radii; and acquiring cell synchronization information of a target cell and a cell identifier of the target cell, wherein the target cell is a cell managed by a target second communication apparatus, and the target second communication apparatus is one of the plurality of second communication apparatuses. In the present application, a second communication apparatus can identify, on the basis of parameters such as a cell radius, whether the current cell is subjected to limited coverage or limited detection complexity, and thus can select a sending waveform for the cell in a targeted manner, thereby simultaneously ensuring a balance between downlink coverage and low detection complexity performance of a first communication apparatus in detecting downlink synchronization signals.

Description

A communication method and apparatus

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410813994.2, 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] After downlink synchronization between the terminal device and the network device, the information of the cell to which the terminal device needs to access can be determined. The terminal device can then access the cell and receive services from the network device within that cell. During downlink synchronization, the network device sends a synchronization signal (which can be called a synchronization signal) to the terminal device. This synchronization signal is generated based on a specific sequence. The terminal device receives the synchronization signal, detects the specific sequence, and adjusts its own timing and carrier frequency according to the time and frequency of the detected sequence, or notifies the network device to make adjustments, thereby achieving time and frequency synchronization between the terminal device and the network device.

[0005] When synchronizing downlink, it is usually necessary to consider both coverage and detection complexity. Coverage determines the signal transmission quality, while detection complexity determines the battery life of the terminal device. How to ensure good coverage and low detection complexity at the same time is an urgent problem to be solved. Summary of the Invention

[0006] This application provides a communication method and apparatus to balance the complexity of downlink coverage and downlink synchronization detection.

[0007] Firstly, this application provides a communication method that can be executed by a first communication device. Unless otherwise specified, the first communication device in this application can be the first communication device itself (e.g., a terminal device), a component within the first communication device (e.g., a processor, chip, or chip system), or a logic module or software that implements all or part of the functions of the first communication device. This application does not specifically limit the scope of the method.

[0008] This method can be applied to 5G communication systems or future network communication systems, and can also be applied to non-terrestrial communication systems; this application does not specifically limit its application. The execution is as follows:

[0009] The first communication device receives a synchronization signal, which includes multiple downlink synchronization signals from multiple second communication devices. Each downlink synchronization signal corresponds one-to-one with a second communication device and is related to the cell radius of the cell managed by the second communication device. At least two downlink synchronization signals with different waveforms correspond to cells with different cell radii. The first communication device obtains the cell synchronization information and cell identifier of the target cell. The target cell is a cell managed by the target second communication device, which is one of multiple second communication devices.

[0010] It should be noted that the second communication device can be the second communication device itself (e.g., a network device), a component within the second communication device (e.g., a processor, chip, or chip system), or a logic module or software that implements all or part of the functions of the second communication device. Typically, one second communication device manages only one cell. Different second communication devices correspond to different cells. The second communication device determines the downlink synchronization signal corresponding to that cell based on the information of that cell.

[0011] In this application, the second communication device determines the downlink synchronization signal with reference to the cell radius of the cell it manages. Different second communication devices may generate downlink synchronization signals with different cell radii, and the corresponding waveforms may be the same or different. The second communication device can identify whether the current cell is coverage-limited or detection complexity-limited based on parameters such as cell radius, and thus can select the appropriate transmission waveform for the cell, thereby simultaneously ensuring a balance between downlink coverage and low detection complexity performance for the first communication device in detecting the downlink synchronization signal. It should be understood that coverage-limited means that poor coverage is the highest priority issue affecting user communication within the current cell, and detection complexity-limited means that high detection complexity is the highest priority issue affecting user communication within the current cell.

[0012] Secondly, this application provides a communication method that can be executed by a second communication device. Unless otherwise specified, the second communication device in this application can be the second communication device itself (e.g., a network device), a component within the second communication device (e.g., a processor, chip, or chip system), or a logic module or software that implements all or part of the functions of the second communication device. This application does not specifically limit the scope of the application.

[0013] This method can be applied to 5G communication systems or future network communication systems, and can also be applied to non-terrestrial communication systems; this application does not specifically limit its application. The execution is as follows:

[0014] The second communication device acquires a downlink synchronization signal, which is related to the cell radius of the cell managed by the second communication device; and transmits the downlink synchronization signal.

[0015] In one alternative approach, the downlink synchronization signal is related to the cell radius of the cell managed by the second communication device, including:

[0016] The cell radius of the cell managed by the second communication device is less than the first radius threshold, and the waveform of the downlink synchronization signal is the first waveform; or, the cell radius of the cell managed by the second communication device is not less than the first radius threshold, and the waveform of the downlink synchronization signal is the second waveform; wherein the second waveform is different from the first waveform.

[0017] It should be noted that the second waveform can be understood as a single-carrier waveform, while the first waveform can be understood as a multi-carrier waveform.

[0018] In this application, when the cell radius is less than a first radius threshold, users at the cell edge may not receive the downlink synchronization signal, thus preventing them from accessing the cell. The downlink synchronization signal corresponding to the cell uses a first waveform, which ensures downlink coverage. When the cell radius is not less than the first radius threshold, the coverage for users within the cell is no longer limited, and the waveform of the downlink synchronization signal corresponding to the cell is a second waveform. Since the second waveform uses more cyclic shifting, the complexity of downlink synchronization detection can be reduced. Using the same or different downlink synchronization signal waveforms for different target cell radii can balance the complexity of downlink coverage and downlink synchronization detection.

[0019] In one alternative approach, the first waveform is an orthogonal frequency division multiplexing (OFDM) waveform; the second waveform is a discrete fourier transform spread orthogonal frequency division multiplexing with frequency-domain spectral shaping (DFT-S-OFDM) waveform.

[0020] In one alternative approach, when the waveform of the downlink synchronization signal is the first waveform, the downlink synchronization signal is modulated by quadrature phase shift keying (QPSK) or binary phase shift keying (BPSK); or, when the waveform of the downlink synchronization signal is the second waveform, the downlink synchronization signal is modulated by QPSK or π / 2-BPSK.

[0021] It should be understood that modulation of the downlink synchronization signal refers to the modulation of the downlink synchronization sequence and / or downlink broadcast information to obtain modulation symbols. These modulation symbols are then processed to generate the corresponding waveform for the downlink synchronization signal.

[0022] In this application, different modulation methods are used for downlink synchronization signals with different waveforms, which can ensure that the downlink synchronization signal has a lower peak to average power ratio (PAPR).

[0023] In one alternative approach, the downlink synchronization signal includes a primary synchronization signal and a secondary synchronization signal.

[0024] In one alternative approach, the downlink synchronization signal also includes a physical broadcast signal.

[0025] In one alternative approach, when the downlink synchronization signal consists of a primary synchronization signal, a secondary synchronization signal, and a physical broadcast signal, the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal occupy different time-domain resources of the first resource.

[0026] It is important to understand that frequency division multiplexing of downlink signals using DFT-s-OFDM waveforms (i.e., the second waveform) often disrupts the single-carrier characteristics of this waveform, leading to an increase in the PAPR of the signal. In this application, the primary synchronization signal, secondary synchronization signal, and physical broadcast signal occupy different time-domain resources of the first resource, which can ensure that the downlink synchronization signal has a lower PAPR. In one optional approach, the first resource occupies 4 OFDM symbol resources and K subcarriers, where K is a positive integer; the different time-domain resources occupied by the primary synchronization signal, secondary synchronization signal, and physical broadcast signal in the first resource include:

[0027] The primary synchronization signal occupies the first OFDM symbol resource, the secondary synchronization signal occupies the second OFDM symbol resource, and the physical broadcast signal occupies the third and fourth OFDM symbol resources, and occupies K subcarriers; or, the primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and third OFDM symbol resources, and occupies K subcarriers, while the secondary synchronization signal occupies the fourth OFDM symbol resource; or, the primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and fourth OFDM symbol resources, and occupies K subcarriers, while the secondary synchronization signal occupies the third OFDM symbol resource.

[0028] This ensures that the downlink synchronization signal has a lower PAPR.

[0029] In one alternative approach, K is 288.

[0030] Where K represents 24*12 subcarriers, this ensures that the spectral efficiency of the physical broadcast signal is kept as similar as possible to that of the physical broadcast signal in the existing protocol, thereby guaranteeing the detection performance of the downlink signal.

[0031] In one alternative approach, the cross-correlation value of the downlink synchronization signals of different waveforms is lower than a first cross-correlation threshold.

[0032] Based on this, it can be ensured that the downlink synchronization signals corresponding to different cells all have a low PAPR.

[0033] In one alternative approach, the downlink synchronization signal is also related to the location of the target cell and / or the environmental parameters of the target cell.

[0034] It should be noted that the location of the target cell can be indicated using a world geographic coordinate system or by the tracking area. Environmental parameters of the target cell indicate the presence of signal obstructions; for example, the presence of numerous tall buildings in the target cell increases the probability of signal blockage. Based on this, it is possible to more accurately determine whether the current cell is limited by coverage or detection complexity, thus allowing for the selection of a more suitable transmission waveform.

[0035] In one alternative approach, the first communication device further acquires a first synchronization signal, the first synchronization signal being a primary synchronization signal; and determines the waveform of the downlink synchronization signal of the target cell by performing correlation detection between the first synchronization signal and the primary synchronization signal.

[0036] It should be understood that, since the distances of the multiple second communication devices from the first communication device are different, the first communication device can only detect the downlink synchronization signal of the target cell corresponding to the maximum received power, and thus determine the cell identifier of the target cell.

[0037] In this application, the second communication device determines the waveform of the downlink synchronization signal based on the pre-configured primary synchronization signal, thereby enabling the correct detection of the auxiliary synchronization signal and the physical broadcast signal, and improving the detection performance.

[0038] In one alternative approach, the first communication device acquires a second synchronization signal and a third synchronization signal, wherein the waveform of the second synchronization signal is a second waveform and the waveform of the third synchronization signal is a first waveform, and the second and third synchronization signals are the main synchronization signals; based on the correlation detection between the second and third synchronization signals and the synchronization signal, the waveform of the downlink synchronization signal of the target cell is determined.

[0039] In this application, the waveform of the downlink synchronization signal is determined by configuring the main synchronization signal with different waveforms, thereby enabling the correct detection of the auxiliary synchronization signal and the physical broadcast signal, and improving the detection performance.

[0040] In one alternative approach, if the first correlation value is lower than the second correlation value, the waveform corresponding to the downlink synchronization signal is determined to be the second waveform; if the first correlation value is not lower than the second correlation value, the waveform corresponding to the downlink synchronization signal is determined to be the first waveform; wherein, the first correlation value is the maximum value of the cross-correlation between the second synchronization signal and the downlink synchronization signal, and the second correlation value is the maximum value of the cross-correlation between the third synchronization signal and the downlink synchronization signal.

[0041] Based on this, auxiliary synchronization signals and physical broadcast signals can be detected correctly, improving detection performance.

[0042] Thirdly, this application provides a communication device, which can be a terminal device or a network device. The communication device has the functions to implement the first or second aspects described above. For example, the communication device includes modules, units, or means corresponding to the steps involved in the first or second aspects. These functions, units, or means can be implemented by software, hardware, or hardware executing corresponding software.

[0043] In one possible design, the communication device includes a processing unit and a transceiver unit. The transceiver unit can be used to send and receive signals to enable communication between the communication device and other devices. The processing unit can be used to perform some internal operations of the communication device. The transceiver unit can be called an input / output unit, a communication unit, etc., and can be a transceiver; the processing unit can be a processor. When the communication device is a module (e.g., a chip) in a communication device, the transceiver unit can be an input / output interface, input / output circuit, or input / output pins, etc., and can also be called an interface, communication interface, or interface circuit, etc.; the processing unit can be a processor, processing circuit, or logic circuit, etc.

[0044] In another possible design, the communication device includes a processor and may further include a transceiver for transmitting and receiving signals. The processor executes program instructions to perform the methods in any possible design or implementation of the first aspect described above. The communication device may also include one or more memories coupled to the processor. The memories may store necessary computer programs or instructions for implementing the functions involved in the first or second aspect described above. The processor can execute the computer programs or instructions stored in the memory, and when the computer programs or instructions are executed, the communication device implements the methods in any possible design or implementation of the first or second aspect described above.

[0045] In another possible design, the communication device includes a processor that can be coupled to a memory. The memory can store necessary computer programs or instructions for implementing the functions described in the first or second aspect above. The processor can execute the computer programs or instructions stored in the memory, causing the communication device to implement the methods in any possible design or implementation of the first or second aspect above, when the computer programs or instructions are executed.

[0046] In another possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and to perform the methods in any possible design or implementation of the first or second aspect described above.

[0047] Understandably, in the third aspect described above, the processor can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc.; when implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. Furthermore, there can be one or more processors, and one or more memories. The memory can be integrated with the processor or separated from it. In specific implementations, the memory can be integrated with the processor on the same chip or disposed on different chips. This application does not limit the type of memory or the arrangement of the memory and processor.

[0048] Fourthly, embodiments of this application provide a communication system, which includes the first communication device and the second communication device described above, wherein the first communication device or the second communication device is used to implement the method in any possible design or implementation of the first or second aspect described above.

[0049] Fifthly, this application provides a chip system including a processor and potentially a memory, the processor being used to implement the methods described in the first or second aspect above. The chip system may be composed of chips or may include chips and other discrete devices. The memory is used to store data related to implementing any possible design in the first or second aspect, such as relationships, and the processor is used to implement the processing flow related to any possible design in the first or second aspect. No specific limitations are specified herein.

[0050] Sixthly, this application also provides a computer-readable storage medium, which may be a volatile storage medium or a non-volatile storage medium, wherein the computer-readable storage medium stores computer-readable instructions, which, when executed on a computer, cause the computer to perform the methods as described in the first or second aspect.

[0051] In a seventh aspect, this application provides a computer program product containing instructions that, when run on a computer, cause the computer to perform the methods of the embodiments of the first or second aspect described above.

[0052] For the technical effects that can be achieved in the second to seventh aspects mentioned above, please refer to the description of the technical effects that can be achieved by the corresponding possible design schemes in the first aspect mentioned above. This application will not repeat them here. Attached Figure Description

[0053] Figure 1 shows a schematic diagram of a communication system provided in an embodiment of this application;

[0054] Figure 2 shows a schematic diagram of downlink synchronization signal time-frequency resources; Figure 3 shows a schematic diagram of Z4 sequence generation;

[0055] Figure 4 shows a flowchart of a communication method provided in an embodiment of this application;

[0056] Figure 5 shows a schematic diagram of a downlink synchronization signal time-frequency resource provided in an embodiment of this application;

[0057] Figure 6 shows a schematic diagram of a waveform generation process for DFT-s-OFDM provided in an embodiment of this application;

[0058] Figure 7 shows a schematic diagram of the communication device provided in an embodiment of this application;

[0059] Figure 8 shows a schematic diagram of the structure of the communication device provided in an embodiment of this application. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this application clearer, a further detailed description of this application will be provided below in conjunction with the accompanying drawings. The specific operational methods in the method embodiments can also be applied to the device embodiments or system embodiments. In the description of this application, unless otherwise stated, "multiple" means two or more. Therefore, implementations of the device and method can be referred to mutually, and repeated details will not be repeated.

[0061] The technical solutions provided in this application can be applied to 5G systems, or to future communication systems or other similar communication systems. Furthermore, the technical solutions provided in 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. In this application, the above terms all refer to links established between devices of the same type, and their meanings are the same. The so-called "same type of devices" can be links between terminal devices, links between base stations, links between relay nodes, etc., and this application does not limit this.

[0062] Figure 1 is a schematic diagram of the architecture of the communication system 1000 used in an embodiment of this application. As shown in Figure 1, the communication system includes a wireless access network 100 and a core network 200. Optionally, the communication system 1000 may also include an Internet 300. The wireless access network 100 may include at least one wireless access network device (110a and 110b in Figure 1) and at least one terminal (120a-120j in Figure 1). The terminal is connected to the wireless access network device wirelessly, and the wireless access network device is connected to the core network wirelessly or via a wired connection. The core network device and the wireless access network device may be independent physical devices, or the functions of the core network device and the logical functions of the wireless access network device may be integrated on the same physical device, or a single physical device may integrate some of the functions of the core network device and some of the functions of the wireless access network device. Terminals and wireless access network devices can be interconnected via wired or wireless connections. Figure 1 is only a schematic diagram; the communication system may also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1.

[0063] Wireless access network equipment can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a 5G mobile communication system, a next-generation base station in a future communication system, a base station in a future mobile communication system, or an access node in a wireless-fidelity (WiFi) system; it can also be a module or unit that performs some of the functions of a base station. In some deployments, a gNB can include a centralized unit (CU) and a distributed unit (DU). The CU implements some of the functions of the gNB, and the DU implements some of the functions of the gNB. For example, the CU is responsible for handling non-real-time protocols and services. For example, it implements radio resource control (RRC), service data adaptation protocol (SDAP) functions, and packet data convergence protocol (PDCP) layer functions. The DU is responsible for handling physical layer protocols and real-time services. For example, it can implement the functions of the radio link control (RLC) layer, medium access control (MAC) layer, and physical (PHY) layer. The gNB can also include an active antenna unit (AAU). The AAU implements some physical layer processing functions, radio frequency processing, and related functions of the active antenna. Since the information in the RRC layer ultimately becomes the information in the PHY layer, or is derived from the information in the PHY layer, in this architecture, higher-layer signaling (e.g., RRC layer signaling) can also be considered to be sent by the DU, or by the DU and AAU. It is understood that the network device can be one or more of the following: CU node, DU node, and AAU node. Furthermore, the CU can be a network device in the radio access network (RAN), or a network device in the core network (CN); this application does not limit this. Additionally, in the embodiments of this application, the network device provides services to the cell, and the terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to network equipment (such as a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell.For example, small cells can include: metro cells, micro cells, pico cells, femto cells, etc. Because small cells have small coverage areas and low transmission power, they can provide high-speed data transmission services. Furthermore, in other possible cases, the network device can be other devices that provide wireless communication functions for terminal devices. The embodiments of this application do not limit the specific technology or device form used in the network device. For example, in an open radio access network (ORAN) system, a CU can also be called an O-CU (open CU), a DU can also be called an O-DU, a CU-CP can also be called an O-CU-CP, a CU-UP can also be called an O-CU-UP, and a RU can also be called an O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the CU (or CU-CP, CU-UP), DU, and RU units in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. For specific descriptions of the aforementioned protocol layers, please refer to the relevant technical specifications of the 3rd Generation Partnership Project (3GPP). The radio access network equipment can be a macro base station (as shown in Figure 1, 110a), a micro base station or an indoor station (as shown in Figure 1, 110b), or a relay node or donor node, etc. The embodiments of this application do not limit the specific technology or equipment form used in the radio access network equipment.

[0064] A terminal can also be referred to as a terminal device, user equipment (UE), mobile station, or mobile terminal (MT). Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the specific technologies or device forms used in the terminal.

[0065] Network devices and terminals can be fixed in location or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the network devices and terminals.

[0066] The roles of network devices and terminals can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile network device. For terminals 120j that access the wireless access network 100 via 120i, drone 120i is a network device; however, for network device 110a, 120i is a terminal, meaning that 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a network device-to-network device interface protocol. In this case, relative to 110a, 120i is also a network device. Therefore, both network devices and terminals can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be called communication devices with network device functions, and 120a-120j in Figure 1 can be called communication devices with terminal functions.

[0067] In the embodiments of this application, the functions of the network device can be executed by modules (such as chips) within the network device, or by a control subsystem that includes network device functions. This control subsystem, including network device functions, can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities. Similarly, the functions of the terminal can be executed by modules (such as chips or modems) within the terminal, or by a device that includes terminal functions.

[0068] 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.

[0069] Furthermore, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the order, sequence, priority, or importance of multiple objects. For example, "first waveform" and "second waveform" are only used to distinguish different types, and do not indicate a difference in priority or importance between the two sizes.

[0070] In the embodiments of this application, "send" and "receive" indicate the direction of signal transmission. For example, "send information to XX" can be understood as the destination of the information being XX, which may include direct transmission via the air interface or indirect transmission by other units or modules via the air interface. "Receive information from YY" can be understood as the source of the information being YY, which may include direct reception from YY via the air interface or indirect reception from YY by other units or modules via the air interface. "Send" can also be understood as the "output" of the chip interface, and "receive" can also be understood as the "input" of the chip interface. In other words, sending and receiving can occur between devices, such as between network devices and terminal devices, or within a device, such as between components, modules, chips, software modules, or hardware modules within the device via a bus, wiring, or interface. It is understood that information may undergo necessary processing, such as encoding and modulation, between the source and destination of information transmission, but the destination can understand the valid information from the source. Similar expressions in this application can be understood in a similar way and will not be repeated here.

[0071] In the embodiments of this application, "when," "if," and "if" all refer to the device taking corresponding actions under certain objective circumstances, not a time limit, nor do they require the device to perform a judgment action, nor do they imply any other limitations. Unless otherwise specified, "if" and "if" are interchangeable, and "when" and "in the case of" are interchangeable. "When" and "if" / "if" are interchangeable. In the embodiments of this application, "*" can be used to represent "multiplication."

[0072] The ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the size, content, order, timing, priority, or importance of the multiple objects. For example, the first sequence and the second sequence refer to two different sequences, and do not indicate that the content, priority, or importance of these two sequences are different. Words such as "exemplary" or "for example" are used to indicate that they are examples, illustrations, or explanations. Any embodiment or design that is described as "exemplary" or "for example" in this application should not be construed as being better or more advantageous than other embodiments or design solutions. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0073] To better illustrate the solution of this application, the technical terms involved in this application are explained below:

[0074] 1) Downlink synchronization signal

[0075] Network devices continuously broadcast downlink synchronization signals. Terminal devices detect downlink synchronization signals, perform time-frequency synchronization, and continue until they obtain cell information and access the cell to receive communication services.

[0076] The downlink synchronization signal includes a primary synchronization signal (mainly used for time synchronization, e.g., the primary synchronization signal (PSS)) and a secondary synchronization signal (used to determine the cell identifier, e.g., the secondary synchronization signal (SSS)). In addition to the primary and secondary synchronization signals, the downlink synchronization signal may also include a physical broadcast signal (mainly used to carry critical system messages required for terminal access to the network, e.g., the physical broadcast channel (PBCH)). When the downlink synchronization signal consists of PSS, SSS, and PBCH, its time-frequency structure is shown in Figure 2. In the time domain, one downlink synchronization signal occupies four OFDM symbols (symbols 0 to 3). In the frequency domain, one downlink synchronization signal occupies 20 resource blocks (RBs) (one RB includes 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, subcarriers are reserved on both sides of the PSS and SSS as guard subcarriers, as shown in Figure 2, where the blank areas on both sides of the SSS are guard subcarriers. These guard subcarriers are not used to carry signals. The PBCH occupies all subcarriers in symbols 1 and 3, and a portion of the remaining subcarriers in symbol 2 (excluding those occupied by the SSS) (i.e., the remaining subcarriers excluding the guard subcarriers). (Downlink synchronization signal related sequence)

[0077] m-sequence: An m-sequence is short for Longest Linear Feedback Shift Register Sequence. It refers to the longest-period sequence generated by a shift register with linear feedback. Generally, the longest period generated by an n-stage linear feedback shift register is equal to 2. n -1. The m-sequence is short for the longest linear feedback shift register sequence. Here, it is assumed that the feedback function is the XOR operation of all bits in the memory, i.e. Then the output sequence is:

[0078] The m-sequence is determined by the initial bit values ​​stored in the register and the primitive polynomial, where the order of the primitive polynomial is the highest power of the polynomial. For example, f(x) = x 7 The recursive formula corresponding to +x+1 is s(t)+s(t-6)+s(t-7)=0. For binary operations, they are all defined as modulo 2 operations, that is, -1mod2=1mod2(-1+0), 1+1=0, 1+0=1, 0+0=0. Therefore, the above formula can be transformed into the recursive formula s(t)=s(t-6)+s(t-7), where mod is the modulo operation.

[0079] Generally, for multivariate or binary sequences, consider the primitive polynomial: a i For any ∈{0,1,2,…M}, if it is a binary sequence, M=1; if it is a quaternion sequence, M=3, and so on. The recursive formula is: For a quaternion sequence, addition is defined on {0,1,2,3}, meaning the result of addition must be modulo 4, i.e., -1 = 3, -2 = 2, -3 = 1.

[0080] Gold sequences: Gold sequences are also a type of pseudo-random sequence. They can be seen as obtained by performing an element-wise XOR operation on two sequences with different primitive polynomials. Gold sequences have good autocorrelation and cross-correlation properties; moreover, the number of Gold sequences is large, making it easy to carry information.

[0081] Z4 Sequence: The period of the Z4 sequence is the same as that of a binary gold sequence of the same length, and the value set is {0, 1, 2, 3}. Complex signals can be obtained using QPSK modulation. As shown in Figure 3, it represents the primitive polynomial f(x) = x. 3 +2x 2 Example of generating +x+3. Similar to the Gold sequence, the Z4 sequence can be generated using a circular shift register. The generation of the Z4 sequence is similar to that of the m-sequence, except that the Z4 sequence is defined on a four-element ring {0,1,2,3}, therefore addition and subtraction must be modulo 4. For the specific recursive formula, please refer to the above text.

[0082] 3) Physical Cell Identity (PCI)

[0083] PCI is used to identify cells at the physical layer; it can also be called a 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.

[0084] PSS uses m-sequence construction, and the specific sequence generation is shown in Formula 1 below:

[0085] SSS is constructed using Gold sequences as shown in Formula 2 below:

[0086] The community identification number can be calculated using the following formula 3:

[0087] 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. Specifically, it blindly detects the PSS signal on the standard-defined synchronization raster. The synchronization raster defines a set of frequencies with certain intervals within the 5G frequency band, used to divide the 5G frequency band into several SSB (synchronization signal and PBCH block) frequency domain locations. After detecting the PSS signal on a synchronization raster, frequency correction needs to be performed first, followed by 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 perform cross-correlation detection on the SSS using 336 different SSS sequences, and the SSS sequence corresponding to the maximum cross-correlation value is the actual sequence transmitted.

[0088] Furthermore, the Z4 sequence was used as the SSS sequence, based on different initial values ​​and cyclically shifted bearer cell IDs, where the cyclic shifts were selected at equal intervals. The length was 2. n Projecting the Z4 sequence of -1 into the binary domain, the resulting sequence still has a period of 2. n -1, the binary sequence is the m-sequence corresponding to the primitive polynomial generated by projecting the primitive polynomial of the corresponding Z4 sequence onto the binary field. For a length of L=2 r For a Z4 sequence with a cross-correlation value of -1, the maximum cross-correlation value is the maximum value of the cross-correlation value of the binary sequence.

[0089] The following describes the process of using Z4 sequences to carry 1008 / 2016 IDs:

[0090] In one implementation, the total number of cell IDs remains unchanged. Considering that the SSS length is 127, the PSS carries 3 cell IDs, the SSS uses 6 initial values, and 63 cyclic shifts are selected under each initial value (to avoid false detection caused by fractional frequency offset). The SSS carries a total of 378 IDs.

[0091] In another implementation, the cell ID is expanded to 2016. Considering that the SSS length is 127, the PSS carries 1 cell ID, the SSS uses 32 initial values, and 63 cyclic shifts are selected under each initial value. The SSS carries a total of 2016 IDs.

[0092] More IDs can be added in the same way. It should be noted that the interval of the cyclic shift can also be larger, such as 3 / 4 / 5, etc. This application does not limit it.

[0093] 4) Gold sequences are detected using the fast Hadamard transform (FHT).

[0094] FHT is a correlation detection method that performs Hadamard transform on the sequence to quickly calculate the correlation value. Taking the detection of the SSS sequence as a gold sequence as an example, as shown in 3), m0 and m1 have different numbers of cyclic shifts. m0 has 9 cyclic shifts, i.e., [0,1,2,3,4,5,6,7,8], and the value range of m0 is 5×[0,1,2,3,4,5,6,7,8]; m1 has 112 cyclic shifts, and the value range of m1 is [0,1,2,…,111]. When the UE detects SSS, the m sequence corresponding to m0 can be used as a scrambling code, and the m sequence corresponding to m1 can be subjected to fast Hadamard transform detection.

[0095] The primitive polynomial of the m-sequence is f(x) = x 3 +x 2 Taking +1 as an example, this generates 8 sequences, namely {[0,0,0,0,0,0,0,0],[0,0,1,0,1,1,1],[0,1,0,1,1,1,0],[1,0,1,1,1,0,0],[0,1,1,1,0,0,1],[1,1,1,0,0,1,0],[1,1,0,0,1,0,1],[1,0,0,1,0,1,1]}. It can be observed that, except for the all-zero sequence, all other m-sequences are cyclic shifts of a given sequence. For example, the third sequence is obtained by cyclically shifting the second sequence one position to the left. All cyclic shifts of the m-sequences can form a matrix M. Adding an all-zero vector to the first row and first column of matrix M yields a matrix...

[0096] Matrix M: matrix

[0097] matrix It can be obtained from the Hadamard matrix H through row and column transformations, for example, matrix H. The Hadamard matrix H satisfies the following relationship:

[0098] Among them, P L and P S It is a permutation matrix (i.e., each row and each column has only one position with a value of 1), assuming the Hadamard matrix H has a dimension of 2. n *2 n Then P L and P S All dimensions are 2 n *2 n , where n is the order of the primitive polynomial.

[0099] For correlation detection based on FHT, the number of additions required to multiply an arbitrary matrix by a Hadamard matrix is ​​2. n *log2(2 n -1), instead of performing correlation detection based on FHT, for example, directly correlating the received sequence with matrix M, requires 2^32 additions. n *(2 n -1), therefore, correlation detection based on FHT can reduce the complexity of inspection. For example, given a received sequence R = [0,1,0,1,1,1,0], converting R into a binary phase signal [1,-1,1,-1,-1,-1,1], and also converting the elements in matrix M into binary phase signals, and then adding all zeros to the first row, we get... Based on the maximum correlation value, the transmitted m-sequence is determined to be the 3rd sequence [0,1,0,1,1,1,0], and the required number of additions is 2. n *(2 n -1).

[0100] 5) Low-complexity detection of Z4 sequences

[0101] The following example illustrates the transmission and detection process of the Z4 sequence, using 2016 IDs as an example:

[0102] 1. Generate PSS and SSS sequences based on PCI, wherein the PSS and SSS sequences belong to the PSS sequence pool and the SSS sequence pool, respectively.

[0103] 2. Modulate the sequences separately. The SSS sequence is modulated using QPSK, and either the natural mapping or Gray mapping can be selected. Different modulation methods do not affect the cross-correlation between Z4 sequences (the preferred sequence may differ under different modulation methods). The natural mapping is shown in Table 1 below, and the Gray mapping is shown in Table 2 below. In the natural mapping, element 1 corresponds to the complex value j; in the Gray mapping, element 1 corresponds to the complex value -1+1j.

[0104] Table 1

[0105] Table 2

[0106] 3. Based on the above sequence, generate the PSS and SSS of the OFDM waveform and send them.

[0107] 4. The detection process on the receiving side is as follows:

[0108] Taking UE detection of synchronization signals as an example, the UE blindly detects the PSS (Physical Signal and Physical Downlink Broadcast Channel Block) on a standard-defined synchronization raster. The synchronization raster defines a set of frequencies with certain intervals within the 5G frequency band, used to divide the 5G frequency band into several synchronization signal and physical downlink broadcast channel blocks (SSBs) in the frequency domain. Alternatively, the synchronization raster can be considered to include one or more center frequencies where cells may exist, and the UE can detect the PSS at these possible center frequencies. After detecting a PSS signal on a synchronization raster, the UE performs frequency correction and then time slot synchronization. After time slot synchronization, the UE detects the SSS. Since the PSS carries... UE detected Afterwards, Substituting it into the SSS detection, it is about to Substitute into d SSS (n). It can be seen that there are 336 possible SSS sequences. The UE needs to use 336 different SSS sequences to perform cross-correlation detection on the SSS. The SSS sequence corresponding to the maximum cross-correlation value is the SSS sequence sent by the base station.

[0109] Specifically, the receiver equalizes the received SSS signal based on the channel estimation result of the PSS (specifically, the receiver determines the actual transmitted PSS, then determines the channel estimate based on the pre-configured PSS sequence and the received PSS signal, and equalizes the received SSS based on the channel estimate). The equalized SSS is projected onto a binary domain, and the index of the cyclic shift version is determined using FHT. Based on the cyclic shift version index, Z4 sequences generated with different initial values ​​are determined. The initial value is determined based on the maximum likelihood criterion, i.e., the sequences in the local sequence pool and the received signal are correlated sequentially to determine the initial value of the sequence corresponding to the maximum correlation value. Finally, the PCI is determined based on the solved initial value of the sequence and the cyclic shift value.

[0110] It is important to note that the meaning of "projecting to the binary domain" is as follows: if the modulation uses a natural mapping, the imaginary part of the SSS needs to be taken and its absolute value calculated to complete the projection operation; if the modulation uses a Gray mapping, the real part of the SSS needs to be taken to complete the projection operation. Based on the above detection process, the detection complexity can be significantly reduced.

[0111] Please refer to Table 3, which shows the complexity of generating an SSS based on a Gold sequence and a Z4 sequence of length 127. Table 3 uses a PSS carrying 3 cell IDs as an example. Table 4 shows the complexity of generating an SSS based on a Gold sequence and a Z4 sequence with 1008 cell IDs, 2016 cell IDs, and 4032 cell IDs, i.e., the number of computations required to detect an SSS.

[0112] Table 3

[0113] As shown in Table 3, generating SSS based on the Z4 sequence can reduce the detection complexity of SSS, thereby reducing the detection complexity of the synchronization signal. It's important to understand that, for both the gold and Z4 sequences, the source of low-complexity detection is the number of cyclic shifts; the more cyclic shifts, the greater the reduction in detection complexity based on FHT.

[0114] 6) Cross-correlation between PSS and SSS

[0115] Since downlink timing is not obtained when detecting PSS, all time-domain cyclic shifts need to be considered when calculating the cross-correlation value between PSS and SSS. The formula for calculating the cross-correlation value between PSS and SSS is as follows:

[0116] For time-domain sequences s1 and s2 of length L, the cross-correlation value c between s1 and s2 is... max (s1,s2) satisfy:

[0117] The value of τ ranges from [-L, L].

[0118] After normalization, c max (s1,s2) satisfy:

[0119] 7) Cross-correlation between SSS and SSS

[0120] The cross-correlation value c between frequency domain sequences S1 and S2 max (S1,S2) satisfy: After normalization, c max (S1,S2) satisfy:

[0121] During downlink synchronization, coverage and detection complexity must be considered simultaneously. It is unclear how to design the downlink synchronization signal to balance the complexity of downlink coverage and downlink synchronization detection. Therefore, this application provides a communication method to solve the above problems. Referring to Figure 4, this method can be executed through the interaction of a first communication device and a second communication device. Unless otherwise specified, in this application, the first communication device can be the first communication device itself (e.g., a terminal device), a component within the first communication device (e.g., a processor, chip, or chip system), or a logic module or software that implements all or part of the functions of the first communication device. The second communication device can be the second communication device itself (e.g., a network device), a component within the second communication device (e.g., a processor, chip, or chip system), or a logic module or software that implements all or part of the functions of the second communication device. This application does not specifically limit the scope here. Figure 4 illustrates this using a UE as the first communication device and a gNB as the second communication device.

[0122] This method can be applied to 5G communication systems or future network communication systems, and can also be applied to non-terrestrial communication systems; this application does not specifically limit its application. The first communication device receives multiple downlink synchronization signals from multiple second communication devices, with each downlink synchronization signal corresponding one-to-one with a second communication device. The first and second communication devices mentioned below refer to multiple devices; here, only UE, gNB1, gNB2, and gNB3 are used as examples. The execution is as follows:

[0123] Step 401A: gNB1 acquires downlink synchronization signal 1. Downlink synchronization signal 1 is related to the cell radius of the cell managed by gNB1.

[0124] Step 401B: gNB2 acquires downlink synchronization signal 2. Downlink synchronization signal 2 is related to the cell radius of the cell managed by gNB2.

[0125] Step 401C: gNB3 acquires downlink synchronization signal 3. Downlink synchronization signal 3 is related to the cell radius of the cell managed by gNB3.

[0126] It should be noted that the first communication device can construct the downlink synchronization signal with reference to cell information. For example, if the cells covered by the first communication device include cell 1, and the cell information is the cell radius, the first communication device can construct the downlink synchronization signal with reference to the cell radius of cell 1. Furthermore, the downlink synchronization signal can be understood with reference to the descriptions in 1) and 2) above, and will not be elaborated upon here.

[0127] When the downlink synchronization signal consists of a primary synchronization signal, an auxiliary synchronization signal, and a physical broadcast signal, the primary synchronization signal, the auxiliary synchronization signal, and the physical broadcast signal can occupy time-frequency resources as shown in Figure 2 above. They can also occupy different time-domain resources of the first resource while ensuring that the downlink synchronization signal has a lower PAPR.

[0128] For example, the first resource occupies 4 OFDM symbol resources and K subcarriers, where K is a positive integer; typically, K is greater than 240 (20 RBs, 20*12 REs). For example, K is 288 (24 RBs, 24*12 REs), which ensures that the spectral efficiency of the physical broadcast signal is kept as similar as possible to that of the physical broadcast signal in existing protocols, thereby guaranteeing the detection performance of the downlink signal. The primary synchronization signal occupies the first OFDM symbol resource, the secondary synchronization signal occupies the second OFDM symbol resource, and the physical broadcast signal occupies the third and fourth OFDM symbol resources, and occupies K subcarriers; as shown in Figure 5(a), taking K as 288, the primary synchronization signal as PSS, the secondary synchronization signal as SSS, and the physical broadcast signal as PBCH as an example, the first resource occupies 4 OFDM symbol resources, with symbol numbers 0, 1, 2, and 3 respectively, and occupies 288 subcarriers (subcarrier numbers 0 to 287). The PSS occupies the OFDM symbol resources corresponding to symbol number 0, and the subcarriers corresponding to subcarrier numbers 56-182. The SSS occupies the OFDM symbol resources corresponding to symbol number 1, and the subcarriers corresponding to subcarrier numbers 56-182. The PBCH occupies the OFDM symbol resources corresponding to symbols 2 and 3, and the subcarriers corresponding to subcarrier numbers 0-287.

[0129] The primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and third OFDM symbol resources, and occupies K subcarriers; the secondary synchronization signal occupies the fourth OFDM symbol resource. As shown in Figure 5(b), taking K as 288, the primary synchronization signal as PSS, the secondary synchronization signal as SSS, and the physical broadcast signal as PBCH as an example, the first resource occupies 4 OFDM symbol resources, with symbol numbers 0, 1, 2, and 3, and occupies 288 subcarriers (subcarrier numbers 0 to 287). PSS occupies the OFDM symbol resource corresponding to symbol number 0, and the subcarriers corresponding to subcarrier numbers 56 to 182. SSS occupies the OFDM symbol resource corresponding to symbol number 3, and the subcarriers corresponding to subcarrier numbers 56 to 182. PBCH occupies the OFDM symbol resources corresponding to symbols 1 and 2, and the subcarriers corresponding to subcarrier numbers 0 to 287.

[0130] The primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and fourth OFDM symbol resources, and occupies K subcarriers. The secondary synchronization signal occupies the third OFDM symbol resource. As shown in Figure 5(c), taking K as 288, the primary synchronization signal as PSS, the secondary synchronization signal as SSS, and the physical broadcast signal as PBCH as an example, the first resource occupies 4 OFDM symbol resources, with symbol numbers 0, 1, 2, and 3, and occupies 288 subcarriers (subcarrier numbers 0 to 287). PSS occupies the OFDM symbol resource corresponding to symbol number 0, and the subcarriers corresponding to subcarrier numbers 56 to 182. SSS occupies the OFDM symbol resource corresponding to symbol number 2, and the subcarriers corresponding to subcarrier numbers 56 to 182. PBCH occupies the OFDM symbol resources corresponding to symbols 1 and 3, and the subcarriers corresponding to subcarrier numbers 0 to 287.

[0131] Figure 5 above is only an illustrative example. In specific applications, the main synchronization signal, auxiliary synchronization signal, and physical broadcast signal may occupy other symbol resources. This is not specifically limited here. The arrangement order of the main synchronization signal, auxiliary synchronization signal, and physical broadcast signal in the first resource should ensure that the time domain resources occupied by the main synchronization signal are placed before the time domain resources occupied by the auxiliary synchronization signal.

[0132] The execution order of steps 401A to 401C is not limited here.

[0133] Among them, the downlink synchronization signal is related to the cell radius of the cell managed by the second communication device, including:

[0134] The downlink synchronization signal waveform of the cell managed by the second communication device is the first waveform if the cell radius is less than the first radius threshold; or, if the cell radius of the cell managed by the second communication device is not less than the first radius threshold, the downlink synchronization signal waveform is the second waveform; wherein the second waveform is different from the first waveform (i.e., the first waveform and the second waveform are different types of waveforms). It should be noted that the second waveform can be understood as a single-carrier waveform, and the first waveform can be understood as a multi-carrier waveform. In this application, when the cell radius is less than the first radius threshold, users at the cell edge may not receive the downlink synchronization signal, thus resulting in the inability to access the cell. The downlink synchronization signal corresponding to the cell adopts the first waveform, which ensures downlink coverage. When the cell radius is not less than the first radius threshold, the coverage of users within the cell is no longer limited, and the downlink synchronization signal waveform corresponding to the cell is the second waveform. Since the second waveform uses more cyclic shifting, the complexity of downlink synchronization detection can be reduced. For different target cell radii, the same or different downlink synchronization signal waveforms can be used to balance the complexity of downlink coverage and downlink synchronization detection.

[0135] For example, the first waveform is an OFDM waveform; the second waveform is a DFT-s-OFDM waveform. When the downlink synchronization signal waveform is the first waveform, the downlink synchronization signal is modulated by QPSK or BPSK; or, when the downlink synchronization signal waveform is the second waveform, the downlink synchronization signal is modulated by QPSK or π / 2-BPSK. It should be understood that modulation of the downlink synchronization signal refers to modulating the downlink synchronization sequence and / or downlink broadcast information to obtain modulation symbols. The modulation symbols are then processed to generate the downlink synchronization signal using the corresponding waveform. In this application, different modulation methods are used for downlink synchronization signals with different waveforms to ensure that the downlink synchronization signal has a lower PAPR.

[0136] It should be noted that the second waveform is a DFT-s-OFDM waveform. Taking the PSS in the downlink synchronization signal as an example, refer to Figure 6 for understanding. The PSS synchronization sequence is transformed from a time-domain signal to a frequency-domain signal through an M-point DFT, followed by subcarrier mapping, an N-point inverse fast fourier transform (IFFT), the addition of a cyclic prefix (CP), and digital-to-analog conversion to obtain the DFT-s-OFDM waveform. Here, M is the number of subcarriers, and N is the number of sampling points.

[0137] Furthermore, the downlink synchronization signal is also related to the location of the target cell and / or the environmental parameters of the target cell. The location of the target cell can be indicated by a world geographic coordinate system or by the tracking area. The environmental parameters of the target cell indicate the presence of signal obstructions; for example, the presence of numerous tall buildings in the target cell increases the probability of signal obstruction. In this application, the downlink synchronization signal references not only the radius of the reference cell but also the location and environmental parameters of the target cell. Based on this, it is possible to more accurately determine whether the current cell is limited by coverage or detection complexity, thereby allowing for the selection of a more suitable transmission waveform.

[0138] It should also be noted that, considering the potential mutual interference between downlink synchronization signals from different cells, a low cross-correlation threshold is maintained when using different waveforms for downlink synchronization signals from different cells. Specifically, the cross-correlation value of the downlink synchronization signals with different waveforms should be below a first cross-correlation threshold. For example, if the first cross-correlation threshold is set to 0.3, and downlink synchronization signal A (OFDM waveform) and downlink synchronization signal B (DFT-s-OFDM waveform) are transmitted within the same time period, the cross-correlation value should be below 0.3. The following example, using Table 4 (with the primitive polynomials constituting the PSS as an m-sequence and the primitive polynomials constituting the SSS as a Z4-sequence, which can be understood by referring to the explanation in section 2 above), illustrates how to ensure low cross-correlation between different cells when using different waveforms for downlink synchronization signals. In practical applications, the primitive polynomials constituting the downlink synchronization signal can also be gold sequences, ensuring low cross-correlation values ​​for the time-domain mapped PSS / SSS and the frequency-domain mapped PSS / SSS (generally, the time-domain waveform complexity is reduced less, while the frequency-domain waveform complexity is reduced more). This example uses an OFDM waveform as the first waveform and a DFT-s-OFDM waveform as the second. When the PSS waveform is OFDM, the primitive polynomial constituting the PSS is x. 7 +x 4 +1, the initial value of PSS is [1,0,0,0,0,0,0], and when the SSS waveform is OFDM, the primitive polynomial constituting SSS is x. 7 +2x 4 +x+3, the initial value of SSS is one or more of the following sequences:

[0139] [1,0,0,0,0,0,0]，[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]，[1,0,0,0,2,0,2]，[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].

[0140] The SSS cyclic shift corresponding to different cells can be selected at equal intervals (interval greater than 1, for example, set to 2); when the PSS waveform is DFT-s-OFDM, the primitive polynomial constituting the PSS is x. 7 +x+1, the initial value of PSS is [1,0,0,0,0,0,0,0], and when the SSS waveform is DFT-s-OFDM, the primitive polynomial constituting SSS is x. 7 +2x 4 +x+3, the initial value of SSS is as described above. The SSS cyclic shift corresponding to different cells can be selected at equal intervals (the interval is greater than the CP length, for example, set to 10).

[0141] Table 4

[0142] Step 402A: gNB1 sends downlink synchronization signal 1. Correspondingly, the UE receives downlink synchronization signal 1.

[0143] In step 402B, gNB2 sends downlink synchronization signal 2. Correspondingly, the UE receives downlink synchronization signal 2.

[0144] In step 402C, gNB3 sends downlink synchronization signal 3. Correspondingly, the UE receives downlink synchronization signal 3.

[0145] The execution order of steps 402A to 402C is not limited here. The downlink synchronization signals 1 to 3 received by the UE are transmitted within the same time period; that is, the UE receives a synchronization signal resulting from the superposition of downlink synchronization signals 1, 2, and 3. At least two downlink synchronization signals with different waveforms correspond to cells with different cell radii. The downlink synchronization signal actually received by the UE is a composite downlink synchronization signal formed by downlink synchronization signal 1, downlink synchronization signal 2, and downlink synchronization signal 3.

[0146] The second communication device can transmit downlink synchronization signals via broadcast or unicast. The first communication device can detect the downlink synchronization signal by referring to steps 3) and 4) above. The first communication device can also detect the downlink synchronization signal in the following ways:

[0147] In one optional approach, the first communication device further acquires a first synchronization signal, which is a primary synchronization signal; and determines the waveform of the downlink synchronization signal of the target cell by performing correlation detection between the first synchronization signal and the primary synchronization signal. The target cell is a cell managed by a target second communication device, which is one of multiple second communication devices (i.e., one of gNB1 to gNB3). Specifically, after detecting the downlink synchronization signal, the UE determines the identifier of the target cell. It should be understood that, since the multiple second communication devices are at different distances from the UE, the UE can only detect the downlink synchronization signal of the target cell corresponding to the maximum received power, and thus determine the identifier of the target cell. In this application, the second communication device determines the waveform of the downlink synchronization signal based on a pre-configured primary synchronization signal, thereby correctly detecting the secondary synchronization signal and the physical broadcast signal, improving detection performance.

[0148] For example, the UE can pre-configure a PSS (including multiple PSSs of a first waveform and a second waveform), and then randomly select a pre-configured PSS to perform correlation detection with the PSS in the received downlink synchronization signal. If the correlation is lower than a preset threshold, it is determined that the waveform of the received PSS is the same as that of the pre-configured PSS; if the correlation is higher than the preset threshold, it is determined that the waveform of the received PSS is different from that of the pre-configured PSS. When the UE determines the PSS waveform, it then detects the SSS and PBCH.

[0149] In another optional approach, the first communication device acquires a second synchronization signal and a third synchronization signal. The waveform of the second synchronization signal is the second waveform, and the waveform of the third synchronization signal is the first waveform. The second and third synchronization signals are the main synchronization signals. Correlation detection is performed between the second and third synchronization signals and the main synchronization signal to determine the waveform of the downlink synchronization signal of the target cell. If the first correlation value is lower than the second correlation value, the waveform corresponding to the downlink synchronization signal is determined to be the second waveform; if the first correlation value is not lower than the second correlation value, the waveform corresponding to the downlink synchronization signal is determined to be the first waveform. The first correlation value is the maximum cross-correlation value between the second synchronization signal and the downlink synchronization signal, and the second correlation value is the maximum cross-correlation value between the third synchronization signal and the downlink synchronization signal. This application determines the waveform of the downlink synchronization signal by configuring main synchronization signals with different waveforms, thereby correctly detecting auxiliary synchronization signals and physical broadcast signals, and improving detection performance.

[0150] For example, the UE can pre-configure multiple PSS1 (third synchronization signal) waveforms as a first waveform and multiple PSS2 (second synchronization signal) waveforms as a second waveform. Then, it randomly selects a pre-configured PSS1 and performs correlation detection with the PSS in the received downlink synchronization signal. If the correlation is lower than a preset threshold, it is determined that the received PSS and the pre-configured PSS1 waveform are the same. If the correlation is higher than the preset threshold, it randomly selects a pre-configured PSS2 and performs correlation detection with the PSS in the received downlink synchronization signal. If the correlation is lower than the preset threshold, it is determined that the received PSS and the pre-configured PSS2 waveform are different. When the UE determines the PSS waveform, it detects the SSS and PBCH.

[0151] Step 403: The UE obtains the cell synchronization information and cell identifier of the target cell.

[0152] In this application, the second communication device determines the downlink synchronization signal with reference to the cell radius of the cell it manages. Different second communication devices may generate downlink synchronization signals with different cell radii, and the corresponding waveforms may be the same or different. The second communication device can identify whether the current cell is coverage-limited or detection complexity-limited based on parameters such as cell radius, and thus can select the appropriate transmission waveform for the cell, thereby simultaneously ensuring a balance between downlink coverage and low detection complexity performance for the first communication device in detecting the downlink synchronization signal. It should be understood that coverage-limited means that poor coverage is the highest priority issue affecting user communication within the current cell, and detection complexity-limited means that high detection complexity is the highest priority issue affecting user communication within the current cell.

[0153] The foregoing primarily describes the solutions provided by the embodiments of this application from the perspective of device interaction. It is understood that, in order to achieve the above functions, each device may include corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0154] The embodiments of this application can divide the device into functional units according to the above method examples. For example, each function can be divided into a separate functional unit, or two or more functions can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0155] 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 transceiver unit 702. The processing unit 701 is used to control and manage the operation of the communication device 700. The transceiver unit 702 is used to support communication between the communication device 700 and other devices. Optionally, the transceiver 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 transceiver unit may be referred to as an input / output unit, a communication unit, etc., and the transceiver 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 transceiver unit may be an input / output interface, an input / output circuit, or an input / output pin, etc., and may also be referred to as an interface, a communication interface, or an interface circuit, etc.; the processing unit may be a processor, a processing circuit, or a logic circuit, etc. Specifically, the communication device may be the aforementioned network device, terminal, etc.

[0156] In one embodiment, the communication device is a terminal, and the transceiver unit 702 is used to receive synchronization signals. The synchronization signals include multiple downlink synchronization signals from multiple second communication devices. Each downlink synchronization signal corresponds one-to-one with a second communication device and is related to the cell radius of the cell managed by the second communication device. At least two downlink synchronization signals with different waveforms correspond to cells with different cell radii. The processing unit 701 is used to obtain cell synchronization information and cell identifier of the target cell. The target cell is a cell managed by a target second communication device, and the target second communication device is one of multiple second communication devices.

[0157] In another embodiment, the communication device is a network device, the processing unit 701 is used to acquire a downlink synchronization signal, which is related to the cell radius of the cell managed by the second communication device; the transceiver unit 702 is used to transmit the downlink synchronization signal.

[0158] In one alternative approach, the downlink synchronization signal is related to the cell radius of the cell managed by the second communication device, including:

[0159] The cell radius of the cell managed by the second communication device is less than the first radius threshold, and the waveform of the downlink synchronization signal is the first waveform; or, the cell radius of the cell managed by the second communication device is not less than the first radius threshold, and the waveform of the downlink synchronization signal is the second waveform; wherein the second waveform is different from the first waveform.

[0160] In one alternative approach, the first waveform is an OFDM waveform; the second waveform is a DFT-s-OFDM waveform.

[0161] In one alternative approach, when the waveform of the downlink synchronization signal is the first waveform, the downlink synchronization signal is modulated by QPSK or BPSK; or, when the waveform of the downlink synchronization signal is the second waveform, the downlink synchronization signal is modulated by QPSK or π / 2-BPSK.

[0162] In one alternative approach, the downlink synchronization signal includes a primary synchronization signal and a secondary synchronization signal.

[0163] In one alternative approach, the downlink synchronization signal also includes a physical broadcast signal.

[0164] In one alternative approach, when the downlink synchronization signal consists of a primary synchronization signal, a secondary synchronization signal, and a physical broadcast signal, the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal occupy different time-domain resources of the first resource.

[0165] In one alternative approach, the first resource occupies 4 OFDM symbol resources and K subcarriers, where K is a positive integer; the primary synchronization signal, secondary synchronization signal, and physical broadcast signal occupy different time-domain resources of the first resource, including:

[0166] The primary synchronization signal occupies the first OFDM symbol resource, the secondary synchronization signal occupies the second OFDM symbol resource, and the physical broadcast signal occupies the third and fourth OFDM symbol resources, and occupies K subcarriers; or, the primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and third OFDM symbol resources, and occupies K subcarriers, while the secondary synchronization signal occupies the fourth OFDM symbol resource; or, the primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and fourth OFDM symbol resources, and occupies K subcarriers, while the secondary synchronization signal occupies the third OFDM symbol resource.

[0167] In one alternative approach, K is 288.

[0168] In one alternative approach, the cross-correlation value of the downlink synchronization signals of different waveforms is lower than a first cross-correlation threshold.

[0169] In one alternative approach, the downlink synchronization signal is also related to the location of the target cell and / or the environmental parameters of the target cell.

[0170] In one alternative embodiment, the terminal's processing unit 701 is further configured to acquire a first synchronization signal, the first synchronization signal being a primary synchronization signal; and to determine the waveform of the downlink synchronization signal of the target cell by performing correlation detection between the first synchronization signal and the primary synchronization signal.

[0171] In one alternative embodiment, the terminal's processing unit 701 is further configured to acquire a second synchronization signal and a third synchronization signal, wherein the waveform of the second synchronization signal is a second waveform, the waveform of the third synchronization signal is a first waveform, and the second and third synchronization signals are primary synchronization signals; and to determine the waveform of the downlink synchronization signal of the target cell by performing correlation detection with the synchronization signal based on the second and third synchronization signals and the synchronization signal.

[0172] In one alternative approach, if the first correlation value is lower than the second correlation value, the processing unit 701 of the terminal is further configured to determine that the waveform corresponding to the downlink synchronization signal is the second waveform; if the first correlation value is not lower than the second correlation value, the processing unit 701 of the terminal is further configured to determine that the waveform corresponding to the downlink synchronization signal is the first waveform; wherein, the first correlation value is the maximum value of the cross-correlation between the second synchronization signal and the downlink synchronization signal, and the second correlation value is the maximum value of the cross-correlation between the third synchronization signal and the downlink synchronization signal.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] In one design, the processor 801 and / or memory 802 may include an artificial intelligence (AI) module 807 and an AI module 808, which are used to implement 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. For example, the AI ​​module may be a near real-time RIC or a non-real-time RIC.

[0178] 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.

[0179] 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 transceiver unit, transceiver, transceiver circuit, or transceiver, is used to implement the transmission and reception functions of the communication device 800 through the antenna 806.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] To achieve the functions of the communication device shown in Figure 4, this application embodiment 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 the necessary computer programs, instructions, and data of the communication device.

[0186] 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.

[0187] Those skilled in the art will recognize that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0188] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0189] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0190] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0191] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the essential contributing part of the technical solution of this application, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, external hard drives, ROM, RAM, magnetic disks, or optical disks.

[0192] 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, Applied to a first communication device, comprising: The system receives a synchronization signal, which includes multiple downlink synchronization signals from multiple second communication devices. Each downlink synchronization signal corresponds to a second communication device and is related to the cell radius of the cell managed by the second communication device. At least two downlink synchronization signals with different waveforms correspond to cells with different cell radii. Obtain the cell synchronization information and cell identifier of the target cell, wherein the target cell is a cell managed by the target second communication device, and the target second communication device is one of the plurality of second communication devices.

2. The method according to claim 1, characterized in that, The downlink synchronization signal is related to the cell radius of the cell managed by the second communication device, including: The cell radius of the cell managed by the second communication device is smaller than a first radius threshold, and the waveform of the downlink synchronization signal is a first waveform; or, The cell radius of the cell managed by the second communication device is not less than the first radius threshold, and the waveform of the downlink synchronization signal is the second waveform; The second waveform is different from the first waveform.

3. The method according to claim 2, characterized in that, The first waveform is an orthogonal frequency division multiplexing (OFDM) waveform, and the second waveform is an orthogonal frequency division multiplexing (DFT-s-OFDM) waveform extended by discrete Fourier transform.

4. The method according to claim 2 or 3, characterized in that, When the waveform of the downlink synchronization signal is the first waveform, the downlink synchronization signal is modulated by quadrature phase shift keying (QPSK) or binary phase shift keying (BPSK); or, When the waveform of the downlink synchronization signal is the second waveform, the downlink synchronization signal is modulated by QPSK or π / 2-BPSK.

5. The method according to any one of claims 1-4, characterized in that, The downlink synchronization signal includes: Primary synchronization signal and secondary synchronization signal.

6. The method according to claim 5, characterized in that, The downlink synchronization signal also includes: physical broadcast signal.

7. The method according to claim 6, characterized in that, When the downlink synchronization signal is composed of the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal, the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal occupy different time domain resources of the first resource.

8. The method according to claim 7, characterized in that, The first resource occupies 4 OFDM symbol resources and K subcarriers, where K is a positive integer; the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal occupy different time-domain resources of the first resource, including: The primary synchronization signal occupies the first OFDM symbol resource, the secondary synchronization signal occupies the second OFDM symbol resource, and the physical broadcast signal occupies the third and fourth OFDM symbol resources, and occupies K subcarriers; or, The primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and third OFDM symbol resources and K subcarriers, and the secondary synchronization signal occupies the fourth OFDM symbol resource; or, The primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and fourth OFDM symbol resources and occupies K subcarriers, and the secondary synchronization signal occupies the third OFDM symbol resource.

9. The method according to claim 8, characterized in that, K is 288.

10. The method according to any one of claims 1-9, characterized in that, The cross-correlation values ​​of downlink synchronization signals with different waveforms are lower than the first cross-correlation threshold.

11. The method according to any one of claims 1-10, characterized in that, The method further includes: Acquire the first synchronization signal, which is the main synchronization signal; The waveform of the downlink synchronization signal of the target cell is determined by performing correlation detection between the first synchronization signal and the synchronization signal.

12. The method according to any one of claims 2-11, characterized in that, The method further includes: Acquire a second synchronization signal and a third synchronization signal, wherein the waveform of the second synchronization signal is the second waveform, the waveform of the third synchronization signal is the first waveform, and the second synchronization signal and the third synchronization signal are the main synchronization signals; The waveform of the downlink synchronization signal of the target cell is determined by performing correlation detection between the second synchronization signal, the third synchronization signal and the synchronization signal.

13. The method according to claim 12, characterized in that, The step of determining the waveform of the downlink synchronization signal of the target cell by performing correlation detection with the second synchronization signal and the third synchronization signal, and the synchronization signal in accordance with the second synchronization signal and the third synchronization signal, includes: If the first correlation value is lower than the second correlation value, the waveform corresponding to the downlink synchronization signal is determined to be the second waveform; If the first correlation value is not lower than the second correlation value, the waveform corresponding to the downlink synchronization signal is determined to be the first waveform; Wherein, the first correlation value is the maximum value of the cross-correlation between the second synchronization signal and the downlink synchronization signal, and the second correlation value is the maximum value of the cross-correlation between the third synchronization signal and the downlink synchronization signal.

14. The method according to any one of claims 1-13, characterized in that, The downlink synchronization signal is also related to the location of the cell managed by the second communication device, and / or the environmental parameters of the cell managed by the second communication device.

15. A communication method, characterized in that, Applied to a second communication device, including: Acquire a downlink synchronization signal, the downlink synchronization signal being related to the cell radius of the cell managed by the second communication device; Send the downlink synchronization signal.

16. The method according to claim 15, characterized in that, The downlink synchronization signal is related to the cell radius of the cell managed by the second communication device, including: The cell radius of the cell managed by the second communication device is smaller than a first radius threshold, and the waveform of the downlink synchronization signal is a first waveform; or, The cell radius of the cell managed by the second communication device is not less than the first radius threshold, and the waveform of the downlink synchronization signal is the second waveform; The second waveform is different from the first waveform.

17. The method according to claim 16, characterized in that, The first waveform is an orthogonal frequency division multiplexing (OFDM) waveform, and the second waveform is an orthogonal frequency division multiplexing (DFT-s-OFDM) waveform extended by discrete Fourier transform.

18. The method according to claim 16 or 17, characterized in that, When the waveform of the downlink synchronization signal is the first waveform, the downlink synchronization signal is modulated by quadrature phase shift keying (QPSK) or binary phase shift keying (BPSK); or, When the waveform of the downlink synchronization signal is the second waveform, the downlink synchronization signal is modulated by QPSK or π / 2-BPSK.

19. The method according to any one of claims 15-18, characterized in that, The downlink synchronization signal includes: Primary synchronization signal and secondary synchronization signal.

20. The method according to claim 19, characterized in that, The downlink synchronization signal also includes: physical broadcast signal.

21. The method according to claim 20, characterized in that, When the downlink synchronization signal is composed of the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal, the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal occupy different time domain resources of the first resource.

22. The method according to claim 21, characterized in that, The first resource occupies 4 OFDM symbol resources and K subcarriers, where K is a positive integer; the primary synchronization signal, the secondary synchronization signal, and the physical broadcast signal occupy different time-domain resources of the first resource, including: The primary synchronization signal occupies the first OFDM symbol resource, the secondary synchronization signal occupies the second OFDM symbol resource, and the physical broadcast signal occupies the third and fourth OFDM symbol resources, and occupies K subcarriers; or, The primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and third OFDM symbol resources and K subcarriers, and the secondary synchronization signal occupies the fourth OFDM symbol resource; or, The primary synchronization signal occupies the first OFDM symbol resource, the physical broadcast signal occupies the second and fourth OFDM symbol resources and occupies K subcarriers, and the secondary synchronization signal occupies the third OFDM symbol resource.

23. The method according to claim 22, characterized in that, K is 288.

24. The method according to any one of claims 15-23, characterized in that, The cross-correlation values ​​of downlink synchronization signals with different waveforms are lower than the first cross-correlation threshold.

25. The method according to any one of claims 15-24, characterized in that, The downlink synchronization signal is also related to the location of the cell managed by the second communication device, and / or the environmental parameters of the cell managed by the second communication device.

26. A communication device, characterized in that, include: At least one processor and memory; The memory is used to store computer programs or data; The at least one processor is configured to run part or all of the computer program or data to cause the method of any one of claims 1-25 to be performed.

27. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed by a computer, cause the method as described in any one of claims 1-25 to be performed.

28. A computer program product comprising a computer program or instructions, characterized in that, When the computer program or instructions are run on a computer, the method as described in any one of claims 1-25 is performed.

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