Communication method, apparatus, and system

Abstract

The present application relates to the technical field of communications, and discloses a communication method, apparatus, and system. The method comprises: on the basis of a first sequence, a first communication apparatus generates a first signal, and sends the first signal. The first sequence is a cubic polynomial exponential sequence, and the first sequence is obtained on the basis of a phase offset and a cyclic shift of a second sequence. In this way, a cyclic shift is introduced, so that a first sequence has a feature of a time domain cyclic shift. Correspondingly, a reception end can implement PDP detection, thereby ensuring low detection complexity. In addition, since the first sequence is obtained on the basis of a phase offset and a cyclic shift of a second sequence, the first sequence has a feature of a large capacity. In other words, according to the method provided in embodiments of the present application, a sequence capacity can be improved while ensuring low detection complexity.

Description

A communication method, apparatus and system

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411914523.7, filed on December 20, 2024, entitled "A Communication Method, Apparatus and System", 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, apparatus and system. Background Technology

[0004] In wireless communication systems, the Zadoff-Chu (ZC) sequence is used for a variety of possible signals, such as random access signals and reference signals (e.g., measurement reference signals, demodulation reference signals, etc.).

[0005] However, the capacity of ZC sequences is positively correlated with the square of the sequence length, resulting in capacity limitations. For example, taking preambles as an example, preambles are generated based on ZC sequences. Currently, there is a need to increase the capacity of preamble sequences, but the capacity of preambles generated based on ZC sequences is limited and cannot meet this need. Summary of the Invention

[0006] This application provides a communication method, apparatus, and system that obtains a first sequence by phase shifting and cyclic shifting of a base sequence. The first sequence is a cubic polynomial exponential sequence, thereby increasing the sequence capacity while ensuring low detection complexity.

[0007] In a first aspect, embodiments of this application provide a communication method, which can be executed by a first communication device. Unless otherwise specified, the "first communication device" in this application can refer to a communication device (e.g., a terminal device or a network device), a component within that communication device (e.g., a processor, a chip, or a chip system), or a logic module or software capable of implementing all or part of the functions of the communication device. For example, in the method provided in the first aspect, the first communication device generates a first signal according to a first sequence and transmits the first signal; wherein the first sequence is a cubic polynomial exponential sequence, and the first sequence is obtained based on the phase shift and cyclic shift of a second sequence.

[0008] Secondly, embodiments of this application provide a communication method, which can be executed by a second communication device. Unless otherwise specified, the "second communication device" in this application can refer to a communication device (e.g., a network device or terminal device), a component within that communication device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the communication device. For example, in the method provided in the second aspect, the second communication device receives a first signal; based on the first signal, a first sequence is obtained; wherein the first sequence is a cubic polynomial exponential sequence, and the first sequence is obtained based on the phase shift and cyclic shift of a second sequence.

[0009] By employing the methods described in the first or second aspect, a cyclic shift is introduced, giving the first sequence the characteristic of a time-domain cyclic shift. Accordingly, the receiver can implement PDP detection, ensuring low detection complexity. Furthermore, since the first sequence is obtained based on the phase shift and cyclic shift of the second sequence, the first sequence possesses a large capacity characteristic. In other words, the method provided by the embodiments of this application can improve sequence capacity while ensuring low detection complexity.

[0010] Based on the first or second aspect, in one possible design, the maximum value of the sidelobe of the self-ambiguity function of the first sequence within the range of maximum round-trip time delay and maximum Doppler shift is a threshold, and the maximum value of the mutual ambiguity function of the first sequence within the range of maximum round-trip time delay and maximum Doppler shift does not exceed twice the threshold.

[0011] Thus, the first sequence has the characteristics of a low ambiguity region, which can guarantee the correlation performance of the signal (such as anti-interference performance).

[0012] Based on the first or second aspect, in one possible design, the maximum value of the sidelobe of the self-blurring function of the second sequence is the threshold, and the maximum value of the mutual blurring function of the second sequence does not exceed twice the threshold.

[0013] Based on the first or second aspect, in one possible design, the first signal is: a random access signal, a demodulation reference signal, a detection reference signal, or a sensing signal.

[0014] Based on the first or second aspect, in one possible design, the second sequence is a cubic polynomial exponential sequence.

[0015] Based on either the first or second aspect, in one possible design, the expression of the second sequence includes a cubic polynomial, where at least one of the coefficients of the quadratic, linear, and constant terms of the cubic polynomial is 0. For example, the second sequence is denoted as s. a,b,c,d (n), s a,b,c,d (n) satisfies: At least one of b, c, and d is 0.

[0016] Based on the first or second aspect, in one possible design, the second sequence is denoted as s. λ (n), s λ (n) satisfies: Where N represents the length of the second sequence, N is an integer greater than 1, and N is a prime number, λ∈{1,2,…,N-1}. The length of the second sequence is the same as the length of the first sequence.

[0017] Based on the first or second aspect, as one possible implementation (referred to as implementation 1), the value of the cyclic shift is an integer multiple of the maximum round-trip time delay, and the value of the phase shift is an integer multiple of the maximum Doppler frequency shift.

[0018] Based on implementation method 1, the cubic term coefficients of the first sequence are the same as the cubic term coefficients of the second sequence, the quadratic term coefficients of the first sequence are associated with the maximum round-trip time delay, and the linear term coefficients of the first sequence are associated with the maximum round-trip time delay and the maximum Doppler shift.

[0019] Based on implementation method 1, generating a first signal according to a first sequence includes: performing Discrete Fourier Transform (DFT) processing on the first sequence to obtain a third sequence; mapping the elements in the third sequence onto frequency domain resources and performing inverse Fourier transform processing to generate the first signal.

[0020] Based on implementation method 1, in the first example, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0021] or,

[0022] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0023] Optionally, the method further includes: receiving first information and / or second information, wherein the first information is used to indicate the maximum round-trip time delay and the second information is used to indicate the maximum Doppler shift.

[0024] Based on implementation method 1, in the second example, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0025] or,

[0026] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0027] Based on implementation method 1, in the third example, the first sequence is obtained by phase shifting and cyclic shifting the second sequence, including: the first sequence is obtained by phase shifting and cyclic shifting the second sequence and removing the constant phase.

[0028] Based on the third example of implementation method 1, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0029] Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0030] Based on implementation method 1, the first sequence is denoted as s. λ,k,l (n), n = 0, 1, ..., N-1; the first signal is denoted as x(t), and x(t) satisfies:

[0031] Where t represents the time variable, m represents the subcarrier index, and T CPThe duration of the cyclic prefix is ​​indicated by T, which represents the duration of the OFDM symbol.

[0032] Based on the first or second aspect, as another possible implementation (referred to as implementation 2), the cyclic shift is an integer multiple of the maximum Doppler frequency shift, and the phase offset is an integer multiple of the maximum round-trip delay.

[0033] Based on implementation method 2, the cubic term coefficients of the first sequence are the same as those of the second sequence, the quadratic term coefficients of the first sequence are associated with the maximum Doppler frequency shift, and the linear term coefficients of the first sequence are associated with the maximum round-trip time and the maximum Doppler frequency shift.

[0034] Based on implementation method 2, generating a first signal according to a first sequence includes: mapping the elements in the first sequence onto frequency domain resources and performing inverse Fourier transform processing to generate the first signal.

[0035] Based on implementation method 2, in the first example, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0036] or,

[0037] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0038] Based on implementation method 2, in the second example, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0039] or,

[0040] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. FIndicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0041] Based on implementation method 2, in the third example, the first sequence is obtained by phase shifting and cyclic shifting the second sequence, including: the first sequence is obtained by phase shifting and cyclic shifting the second sequence and removing the constant phase.

[0042] Based on the third example of implementation method 2, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0043] Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0044] Based on implementation method 2, the first sequence is denoted as s. λ,k,l (n), n = 0, 1, ..., N-1; the first signal is denoted as x(t), and x(t) satisfies:

[0045] Where t represents the time variable, m represents the subcarrier index, and T CP The duration of the cyclic prefix is ​​indicated by T, which represents the duration of the OFDM symbol.

[0046] For example, in the method provided in the first aspect, the first communication device generates a first signal based on a first sequence; and transmits the first signal; wherein the first sequence is obtained based on a phase offset and cyclic shift of a second sequence, the second sequence being denoted as s. λ (n), s λ (n) satisfies:

[0047] Where N represents the sequence length of the first sequence or the second sequence, N is an integer greater than 1, λ∈{1,2,…,P-1}, and P is the largest prime number not exceeding N. For example, when N is a prime number, P=N.

[0048] In one possible design, the first sequence is denoted as s. λ,k,l (n), sλ,k,l (n) satisfies:

[0049] or,

[0050] Among them, s λ (n) represents the second sequence, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,P-1}. This indicates rounding down to the nearest integer.

[0051] In one possible design, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0052] or,

[0053] Among them, s λ (n) represents the second sequence, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,P-1}. This indicates rounding down to the nearest integer.

[0054] For example, in the method provided in the first aspect, the first communication device generates a first signal according to a first sequence; and transmits the first signal; wherein the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0055] or,

[0056] or,

[0057] or,

[0058] or,

[0059] Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ TΔ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0060] For example, in the method provided in the first aspect, the first communication device generates a first signal according to a first sequence; and transmits the first signal; wherein the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0061] or,

[0062] or,

[0063] or,

[0064] or,

[0065] Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0066] For example, in the method provided in the second aspect, the second communication device receives a first signal and obtains a first sequence based on the first signal; wherein the first sequence is obtained based on a phase shift and cyclic shift of a second sequence, the second sequence being denoted as s. λ (n), s λ (n) satisfies:

[0067] Where N represents the sequence length of the first sequence or the second sequence, N is an integer greater than 1, λ∈{1,2,…,P-1}, and P is the largest prime number not exceeding N. For example, when N is a prime number, P=N.

[0068] In one possible design, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0069] or,

[0070] Among them, s λ (n) represents the second sequence, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,P-1}. This indicates rounding down to the nearest integer.

[0071] In one possible design, the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0072] or,

[0073] Among them, s λ (n) represents the second sequence, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,P-1}. This indicates rounding down to the nearest integer.

[0074] For example, in the method provided in the second aspect, the second communication device receives a first signal and obtains a first sequence based on the first signal; wherein the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0075] or,

[0076] or,

[0077] or,

[0078] or,

[0079] Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift.T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0080] For example, in the method provided in the second aspect, the second communication device receives a first signal and obtains a first sequence based on the first signal; wherein the first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies:

[0081] or,

[0082] or,

[0083] or,

[0084] or,

[0085] Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

[0086] Thirdly, this application provides a communication device that has the functions involved in the first or second aspect above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the first or second aspect above. The functions, units, or means can be implemented by software, or by hardware, or by hardware executing corresponding software.

[0087] In one possible design, the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to transmit 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 functions performed by the processing unit and the communication unit can correspond to the operations involved in the first or second aspect described above.

[0088] In one 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 executed.

[0089] In one possible design, the communication device includes a processor and a memory, the memory of which may store necessary computer programs or instructions for implementing the functions involved in the first or second aspect described above. The processor may execute the computer programs or instructions stored in the memory, and when the computer programs or instructions are executed, cause the communication device to implement the methods in any possible design or implementation of the first or second aspect described above.

[0090] In one possible design, the communication device includes a processor and an interface circuit, wherein the processor is configured to communicate with other devices via the interface circuit and execute the methods in any possible design or implementation of the first or second aspect described above.

[0091] 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.

[0092] Fourthly, this application provides a communication system, which may include a first communication device and a second communication device; wherein the first communication device is used to perform the method described in the first aspect, and the second communication device is used to perform the method described in the second aspect.

[0093] Fifthly, this application provides a computer-readable storage medium storing a computer program (or computer-readable instructions) in which, when a computer reads and executes some or all of the computer-readable instructions, the method in any of the possible designs of the first or second aspect described above is executed.

[0094] For example, a computer-readable storage medium can be any available medium that a computer can access. This includes, but is not limited to, non-transient computer-readable media, random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), CD-ROM or other optical disc storage, magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer.

[0095] Sixthly, this application provides a computer program product that, when read and executed by a computer, causes the method in any of the possible designs of the first or second aspect to be performed.

[0096] In a seventh aspect, this application provides a chip (or chip system) including a processor coupled to a memory storing a computer program; the processor is configured to invoke part or all of the computer program in the memory, such that the method in any of the possible designs of the first or second aspect described above is executed. Attached Figure Description

[0097] Figure 1 is a schematic diagram of the architecture of the communication system used in the embodiments of this application;

[0098] Figure 2 is a schematic diagram of the network device architecture;

[0099] Figure 3 is a schematic diagram of the random access process;

[0100] Figure 4 is a schematic diagram of the fuzzy function for the ZC sequence;

[0101] Figure 5 is a schematic diagram of the processing flow of the sending and receiving ends;

[0102] Figure 6 is a schematic diagram of the fuzzy function of the W sequence;

[0103] Figure 7 is a schematic diagram of the fuzzy function of the cubic polynomial exponential sequence provided in the embodiment of this application;

[0104] Figure 8 is a flowchart illustrating the communication method provided in the embodiments of this application;

[0105] Figure 9 is a possible exemplary block diagram of the apparatus involved in the embodiments of this application;

[0106] Figure 10 is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0107] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings. This application will focus on various aspects, embodiments, or features of a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these solutions may also be used.

[0108] In the embodiments of this application, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as an "example" in this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the term "example" is intended to present concepts in a concrete manner. In the embodiments of this application, "of," "corresponding, relevant," and "corresponding" may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent unless their distinction is emphasized.

[0109] The technical solutions of this application can be applied to various wireless communication systems, such as Universal Mobile Telecommunications System (UMTS), Wireless Local Area Network (WLAN), short-range wireless communication systems (such as sidelink, wireless fidelity, Wi-Fi, Bluetooth, etc.), wired networks, vehicle-to-everything (V2X) communication systems, device-to-device (D2D) communication systems, vehicle-to-everything (V2X) communication systems, integrated communication and sensing systems, 4th generation (4G) mobile communication systems (such as Long Term Evolution (LTE) systems), LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, Worldwide Interoperability for Microwave Access (WiMAX) communication systems, 5th generation (5G) mobile communication systems (such as New Radio (NR) systems), Future Communications systems, or other similar communication systems, without limitation. This application describes the communication system shown in Figure 1 as an example. When applying the technical solution of this application to other communication systems, the devices, components, modules, etc. in the embodiment can be replaced with corresponding devices, components, modules in other communication systems without limitation.

[0110] Figure 1 is a schematic diagram of the architecture of the communication system applied in the embodiments of this application. As shown in Figure 1, the communication system includes an access network 100. Optionally, the communication system may also include a core network 200 and an Internet 300. The access network 100 may include at least one network device, such as 110a and 110b in Figure 1, and may also include at least one terminal device, such as 120a-120j in Figure 1. Specifically, 110a is a base station, 110b is a micro-station, 120a, 120e, 120f, and 120j are mobile phones, 120b is a car, 120c is a fuel dispenser, 120d is a home access point (HAP) deployed indoors or outdoors, 120g is a laptop computer, 120h is a printer, and 120i is a drone. The same terminal device or network device can provide different functions in different application scenarios. For example, the mobile phones in Figure 1 are 120a, 120e, 120f and 120j. Mobile phone 120a can access base station 110a, connect to car 120b, communicate directly with mobile phone 120e and access HAP. Car 120b can access HAP and communicate directly with mobile phone 120a. Mobile phone 120f can access micro-station 110b, connect to laptop 120g and printer 120h. Mobile phone 120j can control drone 120i.

[0111] (1) Network equipment

[0112] A network device is a network-side device with wireless transceiver capabilities. A network device can be a device in a radio access network (RAN) that provides wireless communication capabilities to terminal devices; it can be called an RAN device. The RAN can be an access network in the 3rd Generation Partnership Project (3GPP), such as 4G, 5G, or future networks. The RAN can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a communication network combining two or more of these.

[0113] 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 base station in a future mobile communication system, an access node, transmission node, transceiver node, relay equipment in a WiFi system, or a small or micro station with base station functions, etc.

[0114] Network equipment can also be modules or units that perform some of the functions of a base station. For example, it can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). Here, the CU performs the functions of the radio resource control (RRC) and PDCP protocols of the base station, and can also perform the functions of the service data adaptation protocol (SDAP). The CU can be further divided into a CU control plane (CP) (i.e., CU-CP) and a CU user plane (UP) (i.e., CU-UP). The DU performs the functions of the RLC and MA layers of the base station, and can also perform some or all of the physical layer functions. For specific descriptions of the above protocol layers, please refer to the relevant 3GPP technical specifications. The CU and DU can be set up separately, or they can be included in the same network element, such as in the baseband unit (BBU). The RU can be included in radio frequency equipment or radio frequency units, such as in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). In different systems, CU, DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, and RU can also be called O-RU. 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. The RA device 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 specific device form used in the network equipment.

[0115] For example, communication between network devices and terminal devices follows a certain protocol layer structure, which may include the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the media access control (MAC) layer, and the physical layer (PHY) layer. For detailed descriptions of each of these protocol layers, please refer to the relevant technical specifications of the 3rd Generation Partnership Project (3GPP).

[0116] Figure 2 illustrates a schematic diagram of a network device architecture. As shown in Figure 2, the network device includes one or more functional modules for signal processing. Taking the physical layer function as an example, the network device can perform one or more of the following functions: coding, rate matching, scrambling, modulation, layer mapping, precoding, resource element (RE) mapping, digital beamforming (BF), inverse fast Fourier transformation (IFFT) / adding a cyclic prefix (CP), decoding, rate matching dematching, descrambling, demodulation, inverse discrete Fourier transformation (IDFT), channel equalization (or channel estimation), RE demapping, digital BF, fast Fourier transform (FFT) / CP removal, digital to analog (DA) conversion, analog BF, analog to digital (AD) conversion, or analog BF.

[0117] In Figure 2, CPRI stands for Common Public Radio Interface, used to connect the building base band unit (BBU) and radio remote unit (RRU) of a wireless base station. eCPRI stands for Enhanced Common Public Radio Interface. eCPRI Cat A to F are several categories divided to meet different needs. These categories differ in key performance indicators such as data transmission rate, latency, and functional support to accurately adapt to various service scenarios, from simple mobile Internet access to complex industrial control and high-bandwidth multimedia transmission.

[0118] (2) Terminal equipment

[0119] A terminal device is a user-side device with wireless transceiver capabilities. Terminal devices can also be called terminals, user equipment (UE), mobile stations, mobile terminals, etc. Terminal devices 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), the Industrial Internet, virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. In the embodiments of this application, the device used to implement the functions of the terminal device can be the terminal device itself, or it can be a device that supports the terminal device in implementing that function, such as a chip system or a combination of devices or components that can implement the functions of the terminal device. This device can be installed in the terminal device. The embodiments of this application do not limit the specific technology or specific device form used in the terminal device.

[0120] For example, the terminal device includes one or more functional modules for signal processing. For instance, the terminal device can perform one or more of the following functions: encoding, decoding, rate matching, rate dematching, scrambling, descrambling, modulation, demodulation, layer mapping, FFT, IFFT, IDFT, precoding, RE mapping, channel equalization, RE mapping, digital BF, adding CP, removing CP, etc.

[0121] Network devices and terminal devices 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 also be deployed in the air on airplanes, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of the network devices and terminal devices.

[0122] The roles of network devices and terminal devices can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile network device. For terminal devices 120j that access the wireless access network 100 via 120i, terminal device 120i is a network device; however, for network device 110a, 120i is a terminal device. That is, 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 terminal devices 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 device functions.

[0123] Network devices and terminal devices, network devices and network devices, and terminal devices and terminal devices can communicate through licensed spectrum, unlicensed spectrum, or both licensed and unlicensed spectrum simultaneously; there are no specific limitations.

[0124] The network architecture and business scenarios described in this application are intended to more clearly illustrate the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0125] The following explanations address the relevant terms used in the embodiments of this application. These explanations are intended to make the embodiments of this application easier to understand and should not be construed as strict limitations on the terms within the scope of protection claimed in this application.

[0126] (1) Sequence

[0127] In this application's embodiments, the "sequence" includes one or more elements. These elements can be represented as complex numbers, including a real part and an imaginary part; alternatively, elements can also be represented as real numbers, without any specific limitation.

[0128] For example, s(n) represents a sequence containing N elements, where N is an integer greater than 1. n belongs to {0,…,N-1}, that is, n∈{0,…,N-1}. The “…” in {0,…,N-1} represents an integer between 0 and N-1, for example, when N=5, n∈{0,1,2,3,4}. The N elements in {s(n)} can be s(0),…,s(N-1). It is understood that this embodiment uses a numbering method with a starting number of 0 and incrementing by a step size of 1 as an example, but it is not limited to this. For example, the numbering method can also be: starting number of 1 and incrementing by a step size of 1. Another example is: starting number of X and decrementing by a step size of 1, where X is an integer greater than 1.

[0129] (2) Correlation function and fuzzy function

[0130] Correlation functions include autocorrelation and cross-correlation. The autocorrelation function is the inner product of sequence A and sequence A1, where sequence A1 is the time-delayed version of sequence A. The cross-correlation function is the inner product of sequence B and sequence A1, where sequence A1 is the time-delayed version of sequence A, and sequences A and B reside in the same set of sequences.

[0131] Taking sequence A as an example, the autocorrelation function of sequence s(n) satisfies the following formula:

[0132] Where C(τ) represents the autocorrelation function, s * [(n-τ)mod N] represents the sequence of s(n) after time delay transformation (i.e., sequence A1), where N represents the sequence length, τ represents the time delay, and τ∈{0,1,…,N-1}.

[0133] Ambiguity functions include two types: self-ambiguity functions (AAF) and cross-ambiguity functions (CAF). A self-ambiguity function is the inner product of sequence A and sequence A2, where sequence A2 is the sequence of sequence A after time delay and Doppler frequency shift transformation. A cross-ambiguity function is the inner product of sequence B and sequence A2, where sequence A2 is the sequence of sequence A after time delay and Doppler frequency shift transformation, and sequences A and B reside in the same sequence set.

[0134] Taking sequence A as an example, the self-fuzzy function of sequence s(n) satisfies the following formula:

[0135] Where A(τ,v) represents the self-ambiguity function, s * [(n-τ)mod N]e j2πnv / NLet s(n) be the sequence after time delay and Doppler shift transformation (i.e., sequence A2), N represent the sequence length, τ represent the time delay, τ∈{0,1,…,N-1}, and v represent the Doppler shift, v∈{0,1,…,N-1}.

[0136] (3) Zero-correlation region, low-correlation region, zero-ambiguity region, low-ambiguity region, and sequence capacity

[0137] The zero correlation region refers to the situation where, within a set of sequences, for any two sequences, their correlation function value is zero within a certain time delay range (where there is no Doppler shift).

[0138] The low correlation region refers to the region in which, within a set of sequences, for any two sequences, within a certain time delay range (without Doppler shift), their correlation function value does not exceed a threshold.

[0139] The zero-ambiguity zone refers to the situation where, within a set of sequences, for any two sequences, the ambiguity function is equal to zero within a certain time delay and Doppler range.

[0140] The low ambiguity zone refers to the situation where, within a set of sequences, for any two sequences, the ambiguity function value does not exceed a threshold within a certain time delay and Doppler range.

[0141] Sequence capacity refers to the number of sequences contained in a sequence set.

[0142] (4) ZC sequence

[0143] A ZC sequence is a complex sequence, and the ZC sequence X... u The expression for (n) is as follows:

[0144] Where u is the root index and N is the sequence length.

[0145] In wireless communication systems, ZC sequences are used in various possible signals, such as random access signals. This section describes one possible implementation using ZC sequences in random access signals as an example. Random access signals are used to initiate the random access procedure. For example, a random access signal is derived from a random access preamble, which can be called a random access preamble sequence, preamble sequence, or preamble. Random access signals are carried on the physical random access channel (PRACH).

[0146] Figure 3 is a schematic diagram of a random access procedure provided in an embodiment of this application. As shown in Figure 3, it includes the following steps:

[0147] In step S300, the network device sends random access configuration information to the terminal device, and the terminal device receives the configuration information from the network device. This step can be considered preparatory work before executing the random access procedure and is not part of the random access procedure itself.

[0148] For example, a network device can send random access configuration information to a terminal device via system messages. This configuration information may include a logical root index number, which is used to determine the sequence set (or preamble set) of the current cell. The preamble set includes 64 preambles, i.e., 64 sequences.

[0149] 1) An introduction to the implementation of the terminal device determining the preamble set.

[0150] After receiving the logical root index number (denoted as i), the terminal device queries a predefined table to obtain the physical root index number (denoted as u), and then generates the root sequence X based on the physical root index number. u (n). Furthermore, the terminal device... u (n) Perform a cyclic shift to generate 64 sequences X. u,v (n); if for the root sequence X u If the number of sequences generated by the cyclic shift (n) is less than 64, then continue to generate the next root sequence and perform a cyclic shift on the next root sequence until 64 sequences are generated.

[0151] Wherein, sequence X u,v (n) can be generated by the following formula: X u,v (n)=X u ((n+C v )mod N)

[0152] The above C v is the cyclic shift value, and v is the cyclic shift index.

[0153] The following example, with a root sequence length of 139, illustrates how a terminal device obtains 64 sequences from the preamble set.

[0154] The terminal device receives a logical root index number of 20, obtains a physical root index number of 11 by querying a predefined table, and can then generate a root sequence X. 11 (n). Further, assume v = 0, 1, 2...34, C0 = 0, C1 = 4, C2 = 8, C3 = 12, and so on, that is, each cyclic shift shifts 4 bits backward.

[0155] The first sequence: v = 0, C v =0,X 11,0 (n)=X 11(n), that is, the first sequence is the root sequence X. 11 (n);

[0156] Second sequence: v = 1, C v =4,X 11,1 (n)=X 11 ((n+4) mod 139;

[0157] The third sequence: v = 2, C v =8,X 11,2 (n)=X 11 ((n+8) mod 139;

[0158] And so on;

[0159] The 35th sequence: v = 34, C v =136, X 11,34 (n)=X 11 ((n+136)mod 139.

[0160] Due to the root sequence X 11 (n) If the number of sequences generated by the cyclic shift is less than 64, then continue to generate the next root sequence and perform a cyclic shift on the next root sequence. The physical root index number of the next root sequence in the predefined table is 128 (logical root index number is 21), therefore, the next root sequence is X. 128 (n).

[0161] The 36th sequence: v = 0, C v =0,X 128,0 (n)=X 128 (n), that is, the 36th sequence is the root sequence X. 128 (n);

[0162] The 37th sequence: v = 1, C v =4,X 128,1 (n)=X 128 ((n+4) mod 139;

[0163] And so on;

[0164] The 64th sequence: v = 28, C v =112, X 128,28 (n)=X 128 ((n+112)mod 139, thus obtaining 64 sequences.

[0165] It is understandable that the above description is based on the example of a terminal device generating 64 sequences. In other examples, the terminal device can also determine the physical root index number and cyclic shift value corresponding to each of the 64 sequences without actually generating the sequence. After the terminal device selects one of the sequences (such as sequence a), it generates sequence a according to the physical root index number and cyclic shift value corresponding to sequence a.

[0166] 2) The fuzzy function of the ZC sequence is introduced.

[0167] As mentioned above, when the terminal device determines the preamble set, it generates 64 preambles by first traversing the cyclic shift of the root sequence and then traversing the physical root index. Therefore, the sequence length is N and the maximum round-trip time is Δ. T The maximum Doppler frequency shift is Δ F The ZC sequence can be represented as:

[0168] Wherein, the physical root index u∈{1,2,…,N-1}, different cyclic shifts of the same root sequence constitute the zero correlation region, and arbitrary cyclic shifts of different root sequences constitute the low correlation region (the maximum value of the correlation function is...). For low-speed movement scenarios, the unrestricted set cyclic shift index... This indicates rounding down; for high-speed motion scenarios, a cyclic shift of the constraint set is used to counteract Doppler shift. Specific descriptions of the constraint set can be found in existing protocols. The sequence capacity Ω of the ZC sequence is positively correlated with the square of the sequence length, i.e. The ambiguity function of the ZC sequence within the range of maximum round-trip time delay and maximum Doppler shift can be expressed as:

[0169] Figure 4 shows a schematic diagram of the self-ambiguity function u1 = u2 and the mutual ambiguity function u1 ≠ u2 for the ZC sequence. From Figure 4, we can see that:

[0170] ① The self-ambiguity function of the ZC sequence exhibits periodic peaks in the time-delay Doppler two-dimensional plane. Therefore, by detecting the peak positions of the self-ambiguity function, the signal delay and Doppler frequency shift can be determined, thereby achieving synchronization between the transmitter and receiver.

[0171] ② The maximum sidelobe value of the self-ambiguity function of the ZC sequence is N. When estimating parameters such as signal delay and Doppler shift, the sidelobe characteristics of the self-ambiguity function can be used as a reference. However, since the sidelobes of the ZC sequence are relatively high, they may interfere with the judgment of the main lobe (peak) position, thus leading to ambiguity.

[0172] ③The mutual ambiguity function of the ZC sequence is all in the time-delay Doppler two-dimensional plane. That is, the correlation between different ZC sequences in the time delay-Doppler domain is low, which makes it easier to reduce interference between different terminal devices.

[0173] S301, the terminal device sends a random access signal. This random access signal can be referred to as the first message or message 1 (Msg1) of the random access procedure.

[0174] For example, the terminal device selects a preamble (such as sequence a) from the preamble set of the current cell and generates a random access signal based on sequence a. Specifically, as shown in Figure 5, the terminal device transforms sequence a (e.g., N=839) to the frequency domain through an N-dimensional discrete Fourier transformation (DFT), maps it to the corresponding frequency domain resources, and then performs N... FFT The inverse fast fourier transformation (IFFT) transforms the N-dimensional space into the time domain (e.g., N). FFT =4096), and then add a cyclic prefix to obtain the final symbol sequence (i.e., random access signal), and then send the random access signal to the network device through PRACH.

[0175] S302, the network device sends a random access response (RAR) to the terminal device. This random access response can be referred to as message 2 or message 2 (Msg2) of the random access procedure.

[0176] For example, referring to Figure 5, after receiving the random access signal, the network device removes the cyclic prefix and passes it through N... FFT The network device performs an N-dimensional FFT transform to the frequency domain, and demaps the transformed signal to obtain the frequency domain signals on N subcarriers. Furthermore, for a sequence in the preamble set (such as the local sequence S1), the network device performs an N-dimensional DFT transform on sequence S1 to the frequency domain (or, the network device can directly store the frequency domain signal after the DFT transform), and multiplies the received N-dimensional frequency domain signal with the conjugate of the local N-dimensional frequency domain signal (or, the network device can directly store the signal after conjugate processing of the local N-dimensional frequency domain signal, and then calculate the inner product between the received N-dimensional frequency domain signal and the conjugate processed signal). This process is then repeated. DFT 3D IDFT transform to the time domain (e.g., N) DFT =1024), obtain the correlation function between the received signal and the local signal. If the correlation function exceeds the threshold, it is considered that a random access preamble has been detected, and the timing advance is determined based on the delay. Among them, RAR can include the timing advance.

[0177] The following section describes the detection complexity of the receiving end (i.e., network device).

[0178] Since the preamble is constructed by cyclically shifting the zero-correlation region of the ZC root sequence, a single calculation of the PRACH power-delay profile (PDP) detection can detect the correlation between the received signal and all cyclic shifts of the local ZC root sequence. Therefore, the number of PDP detections is equal to the number M of ZC root sequences used in the preamble set.

[0179] The complexity of PRACH detection includes the following three parts:

[0180] (i) Receive the time-domain signal and transform it to the frequency domain, N FFT The computational complexity of 3D FFT is O(N). FFT logN FFT ).

[0181] (ii) Received signal correlated with local sequence Temporal convolution corresponds to frequency domain multiplication The computational complexity of frequency domain multiplication is O(N).

[0182] Here, a complex number can be represented as The complex multiplication in frequency domain multiplication in (ii) above is obtained through real multiplication and real addition. The conjugate root sequence numbers u and Nu always appear consecutively in the ZC root sequence. For the physical root index number Nu, Complex multiplication The result can be calculated using the existing real-number multiplication result of the physical root index u. Therefore, utilizing the characteristics of the preamble constructed through time-domain cyclic shift and the continuous occurrence of conjugate root sequence numbers, the number of complex multiplications detected by the PDP is...

[0183] (iii)N DFT The computational complexity of 3D IDFT is O(N). DFT log N DFT ).

[0184] S303, the terminal device sends uplink signaling to the network device according to the RAR. This uplink signaling can be referred to as message 3 or message 3 (Msg3) of the random access procedure.

[0185] In step S304, the network device sends a contention resolution message to the terminal device. Correspondingly, the terminal device can receive the contention resolution message from the network device. If the contention resolution message determines that the random access conflict has been won, the random access is considered successful; otherwise, the terminal device determines that the random access has failed. The contention resolution message can be referred to as message 4 or message 4 (Msg4) in the random access procedure.

[0186] It is understood that the random access process shown in Figure 3 above is only one possible process example, and the embodiments of this application do not limit it.

[0187] (5) Exponents and Theorems

[0188] The exponential sum theorem, also known as the Weil bound on exponential sum theorem, specifically refers to:

[0189] If the polynomial of degree d is p(n) = p d n d +p d-1 n d-1 The coefficient of the highest-order term in +…+p1n+p0 Represents the finite field {1,…,N-1}; coefficients of non-highest-order terms. Let d represent a finite field {0,1,…,N-1}, where N is a prime number and d≥1, then the exponent and sum of the exponents are... satisfy: |·| represents the modulus.

[0190] In particular, when d = 2, the exponential sum degenerates into a Gaussian sum. Gauss and satisfaction:

[0191] (6) Cubic polynomial exponential sequence

[0192] A cubic polynomial exponent sequence can be represented as:

[0193] Where N represents the sequence length, an 3 +bn 2 +cn+d represents a cubic polynomial, where a represents the coefficient of the cubic term, b represents the coefficient of the quadratic term, c represents the coefficient of the linear term, and d represents the constant term. The meanings of the cubic, quadratic, linear, and constant terms used in the embodiments of this application can be understood by referring to this definition.

[0194] If the length N of the cubic polynomial exponential sequence is a prime number, then the expression for the cubic polynomial exponential sequence can also be expressed as:

[0195] Where a, b, and c are all finite fields. The elements in the array, where a≠0.

[0196] Furthermore, the cubic polynomial exponent sequence can be determined based on the base sequence and auxiliary sequences. For example, the cubic polynomial exponent sequence can be represented as the base sequence u. a (n) and auxiliary sequence v b,c,d (n) The form of dot product s a,b,c,d (n)=u a (n)·v b,c,d (n). As an example, the base sequence can be represented as: The auxiliary sequence can be represented as: Wherein, the base sequence u a (n) satisfies global low ambiguity; for example, the maximum sidelobe value of the self-ambiguity function of the basis sequence is The maximum value of the mutual ambiguity function of the basis sequences does not exceed Auxiliary sequence v b,c,d (n) Satisfies the requirement of large capacity in low ambiguity region; for example, the maximum value of the mutual ambiguity function of the auxiliary sequence within the range of maximum round-trip time delay and maximum Doppler frequency shift is... The number of auxiliary sequences is positively correlated with the square of the sequence length.

[0197] When a cubic polynomial exponent sequence satisfies the exponent sum theorem, it can also be called a Weil exponent sum sequence, or simply a W sequence. For example, a W sequence can be represented as:

[0198] Where N represents the sequence length, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F Represents the maximum Doppler frequency shift, with cubic coefficient index λ∈{1,2,…,N-1} and quadratic coefficient index λ∈{1,2,…,N-1}. Index of coefficients of the first term The sequence capacity Ω of sequence W is positively correlated with the cube of the sequence length, i.e. The ambiguity function of the W sequence within the range of maximum round-trip time delay and maximum Doppler shift can be expressed as:

[0199] Figure 6 shows a schematic diagram of the self-ambiguity function and the mutual ambiguity function of the W sequence. As can be seen from Figure 6:

[0200] ①The self-ambiguity function of the W sequence has a single-peak characteristic in the time-delay Doppler two-dimensional plane, that is, there is only one main peak and there is no interference from other peaks. Therefore, by determining the position of the peak, the estimated values ​​of time delay and Doppler frequency shift can be obtained directly, which facilitates the synchronization between the transmitter and receiver.

[0201] ②The maximum value of the sidelobe of the self-ambiguity function of the W sequence is That is, the self-ambiguity function sidelobe of the W sequence is relatively low, so there is no ambiguity.

[0202] ③ The mutual ambiguity function of any two W sequences with the same cubic coefficient index has no peak in the ambiguity region. The absence of a peak means that there is no confusion between the signals of different terminal devices in the ambiguity region. This feature can be used to clearly distinguish the signals of each terminal device, so that more terminal devices can communicate at the same time without the communication quality being significantly reduced due to mutual interference of signals.

[0203] Based on the above introduction to terminology, ZC sequences are used in wireless communication systems for various possible signals, such as random access signals, synchronization signals, and reference signals. However, the sequence capacity Ω of a ZC sequence is positively correlated with the square of the sequence length, i.e. There is a capacity limitation issue.

[0204] For example, taking preambles as an example, preambles are generated based on ZC sequences. Currently, there is a need to increase the sequence capacity of preambles, but the sequence capacity of preambles generated based on ZC sequences is limited and cannot meet this need. Furthermore, based on the characteristics of cellular mobile communication and the application scenarios of 5G networks, the need to increase sequence capacity manifests in the following three aspects:

[0205] (1) The frequency bands used in wireless communication are moving from low frequency to mid-to-high frequency. Due to the large path loss on mid-to-high frequency carriers, beams are needed to concentrate signal energy and reduce interference between signals in order to make efficient use of these frequency bands. For example, network devices can perform downlink synchronization signal beam scanning, that is, network devices can use different beam transmission (synchronization signal block, SS) / physical broadcast channel (PBCH) blocks (i.e., SS / PBCH blocks). After the terminal device receives multiple SS / PBCH blocks sent by the network device, it can select the target SS / PBCH block from multiple SS / PBCH blocks based on the measurement values ​​of multiple SS / PBCH blocks, and instruct the terminal device to select the target SS / PBCH block during uplink access.

[0206] One possible indication method is to indicate the target SS / PBCH block using a preamble. Specifically, different SS / PBCH blocks within multiple SS / PBCH blocks correspond to different preambles. This correspondence can be configured by the network device, or it can be preconfigured or predefined. For example, SS / PBCH block 1 corresponds to preambles 1-10 in the preamble set, SS / PBCH block 2 corresponds to preambles 11-20 in the preamble set, SS / PBCH block 3 corresponds to preambles 21-30 in the preamble set, and so on. Furthermore, when the terminal device selects SS / PBCH block 1 as the target SS / PBCH block, the terminal device can randomly select a preamble from preambles 1-10 (such as preamble 1), generate a random access signal based on the selected preamble, and send it. Accordingly, after detecting preamble 1, the network device can know that the target SS / PBCH block selected by the terminal device is SS / PBCH block 1 corresponding to preamble 1. Then, the network device can use the beam corresponding to SS / PBCH block 1 to send RAR to the terminal device.

[0207] Therefore, with the introduction of more beams, more preambles are needed to indicate the beams, which means that the sequence capacity of the preambles needs to be increased.

[0208] (2) As an extension of large-scale machine-type communication, massive communication places new demands on network capabilities, such as requiring a network connection density of 10. 6 -10 8 With an average of 1,000 devices per kilometer, the number of terminal devices (such as Internet of Things (IoT) devices) connecting to the network will further increase in the future. Given this increased number of terminal devices, the probability of collisions when different devices connect to the network is higher. For example, if many terminal devices choose one sequence from the 64 sequences included in the preamble set, the probability of different terminal devices selecting the same sequence is high.

[0209] Therefore, in order to reduce the probability of collisions between different terminal devices, more preambles are needed, that is, the sequence capacity of the preambles needs to be increased.

[0210] (3) In high-speed mobile scenarios such as future high-speed trains (speed approximately 1000 km / h) and low-orbit satellite communication (speed approximately 7.56 km / s), terminal devices also need to access network devices. As the speed of the terminal device increases, the Doppler frequency offset becomes larger, meaning the frequency deviation between the received signal and the original transmitted signal is greater. With the increase in Doppler frequency offset, the number of cyclic shift sequences that can maintain good correlation (within the zero-correlation region) decreases because these sequences are designed based on certain frequency and time characteristics. When the frequency changes significantly, the good autocorrelation originally within the zero-correlation region will be destroyed. Therefore, when generating preambles based on ZC sequences, at least 2 / 3 of the zero-correlation region cyclic shift sequences are unavailable to counteract a frequency offset of ±1 subcarrier; at least 4 / 5 of the zero-correlation region cyclic shift sequences are unavailable to counteract a frequency offset of ±2 subcarriers, thus limiting the sequence capacity of the preamble.

[0211] Therefore, in order to support the access of terminal devices in high-speed mobile scenarios, it is necessary to generate a preamble based on a large-capacity sequence.

[0212] Based on this, embodiments of this application provide a communication method, apparatus, and system that obtains a first sequence by phase shifting and cyclic shifting of a base sequence. The first sequence is a cubic polynomial exponential sequence, thereby increasing the sequence capacity while ensuring low detection complexity.

[0213] Here, we will first briefly explain the overall concept of the embodiments of this application: As can be seen from the previous introduction about cubic polynomial exponential sequences, the sequence capacity of a cubic polynomial exponential sequence is positively correlated with the cube of the sequence length, that is, a cubic polynomial exponential sequence has the characteristic of large capacity. Therefore, one possible design idea is to generate signals based on cubic polynomial exponential sequences to meet the requirement of large capacity.

[0214] However, taking the preamble as an example, the terminal device determines the preamble set (i.e., 64 preambles) by first traversing the cyclic shifts of the root sequence and then traversing the physical root index number. It then selects a preamble from the set to generate a random access signal and transmit it. Therefore, the network device can detect the correlation between the received signal and all cyclic shifts of the local ZC root sequence in a single calculation using PDP detection, resulting in lower detection complexity. The aforementioned cubic polynomial exponential sequence (such as...) It does not have the characteristic of time-domain cyclic shift. If the preamble is generated based on the cubic polynomial exponential sequence, then the different sequences in the preamble set are obtained based on different λ or different k or different l. The different sequences are not cyclically shifted from each other. Therefore, network devices cannot realize PDP detection. Compared with ZC sequence, the detection complexity of cubic polynomial exponential sequence is higher.

[0215] Therefore, in this embodiment, a cubic polynomial exponential sequence is generated by cyclic shifting the base sequence to give it the characteristics of time-domain cyclic shifting, thereby facilitating PDP detection at the receiver and reducing detection complexity. Optionally, a phase shift is introduced, i.e., a cubic polynomial exponential sequence is generated by phase shifting and cyclic shifting the base sequence, giving it a large capacity characteristic. As shown in Figure 7, the self-ambiguity function of the cubic polynomial exponential sequence generated by phase shifting and cyclic shifting the base sequence has a single-peak characteristic in the time-delay Doppler two-dimensional plane. The maximum value of the sidelobes of the self-ambiguity function within the range of maximum round-trip delay and maximum Doppler frequency shift is a threshold (e.g., a threshold of 1). N is the sequence length), and the maximum value of the mutual ambiguity function within the range of maximum round-trip time delay and maximum Doppler shift does not exceed twice the threshold. In other words, the cubic polynomial exponential sequence provided in this application has low ambiguity region characteristics, which can guarantee the correlation performance of the signal (such as anti-interference performance).

[0216] The communication method provided in this application is described below with reference to specific embodiments. The communication method provided in this application can be applied to communication between network devices and terminal devices, or between network devices, or between terminal devices; the specific application is not limited. The communication method provided in this application involves a first communication device and a second communication device. The first communication device is the signal transmitting side, and the second communication device is the signal receiving side. For example, the first communication device may be a terminal device or a component of a terminal device, such as a chip (e.g., a baseband chip) or chip system disposed in the terminal device; the second communication device may be a network device or a component of a network device, such as a chip or chip system disposed in the network device; the specific application is not limited to this. In this application, the example of "the first communication device being a terminal device and the second communication device being a network device" is used for description.

[0217] Figure 8 is a flowchart illustrating the communication method provided in this embodiment. As shown in Figure 8, the process may include:

[0218] S801, the terminal device generates a first signal according to the first sequence.

[0219] For example, the first signal can be a variety of possible signals, such as a random access signal, a reference signal, or a sensing signal. The reference signal may include a sounding reference signal (SRS), a demodulation reference signal (DMRS), etc. Optionally, when the first signal is a random access signal, implementation method 1 described below can be used; when the first signal is a reference signal, implementation method 2 described below can be used; the specific implementation is not limited thereto.

[0220] The first sequence is a cubic polynomial exponent sequence, such as the W sequence. Optionally, the expression of the first sequence includes a cubic polynomial, where the cubic coefficient index is associated with the quadratic and linear coefficients, and the quadratic coefficient index is associated with the linear coefficient.

[0221] The first sequence is obtained by phase shifting and cyclic shifting the second sequence. The first and second sequences have the same length. The second sequence can be called the base sequence or other possible names. The second sequence is also a cubic polynomial exponential sequence; for example, the second sequence is denoted as s. a,b,c,d (n), s a,b,c,d (n) satisfies: N represents the length of the second sequence, and N is an integer greater than 1. When N is a prime number, the expression for the cubic polynomial exponential sequence can also be expressed as: In this application, the example of "N being a prime number" is used for description.

[0222] The expression for the second sequence includes a cubic polynomial an. 3 +bn 2 +cn+d, in one example, at least one of the coefficients of the quadratic, linear, and constant terms of the cubic polynomial in the second sequence is 0, that is, at least one of b, c, and d is 0. For example, if b, c, and d are all 0, and a = λ, then the second sequence can be represented as: N is a prime number. It can be seen that when b, c, and d are all 0, the cubic polynomial of the second sequence only includes cubic terms. In this case, the complexity of phase shifting and cyclic shifting of the second sequence is lower (compared to the case where b, c, and d are not 0). For example, for the sequence... The complexity of performing phase shifting and cyclic shifting is lower than that of performing sequence shifting. (i.e., a = λ, b, c, d are all 1) to perform phase shift and cyclic shift complexity.

[0223] For example, there are multiple specific implementations of obtaining the first sequence based on the phase shift and cyclic shift of the second sequence. The following describes two possible implementations in conjunction with implementation method 1 and implementation method 2.

[0224] (1) Implementation method 1

[0225] In implementation method 1, the value of the cyclic shift can be an integer multiple of the maximum round-trip time (RTD), and the value of the phase shift can be an integer multiple of the maximum Doppler frequency shift. The maximum RTD and / or maximum Doppler frequency shift are cell-related parameters, which can be configured by the network device or indicated to the terminal device. For example, the network device sends first information and / or second information via system messages (or other possible messages), where the first information indicates the maximum RTD and the second information indicates the maximum Doppler frequency shift.

[0226] ① As an example of implementation method 1 (referred to as Example 1), the first sequence can be obtained by first phase shifting the second sequence and then performing a cyclic shift.

[0227] For example, let the first sequence be s. λ,k,l (n), s λ,k,l (n) satisfies the following formula 1:

[0228] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F This indicates the value of the phase offset.

[0229] Alternatively, by expanding Equation 1 through calculation, s can be obtained. λ,k,l (n) satisfies the following formula 2:

[0230] In other words, Formula 1 and Formula 2 are equivalent formulas.

[0231] Taking the first signal as a random access signal as an example, the terminal device can first determine the preamble set (assuming the preamble set includes A preambles), then select a sequence (such as the first sequence) from the preamble set, and generate a random access signal based on the first sequence. When the first sequence satisfies the above formula 1 (or formula 2), as a possible implementation, the network device can configure or indicate the initial values ​​of λ, k, and l, for example, the initial values ​​of λ, k, and l are λ0, k0, and l0, respectively; correspondingly, the terminal device determines the sequence based on the initial values ​​of λ, k, and l. Furthermore, the terminal device first iterates through the possible values ​​of k based on its initial value, generating A sequences (e.g., A is greater than or equal to 64, such as A = 64, 128, or 256). If the number of sequences generated by iterating through the possible values ​​of k is less than A, then it iterates through the possible values ​​of l based on its initial value. If the number of sequences generated by iterating through the possible values ​​of k and l is less than A, then it iterates through the possible values ​​of λ based on its initial value. Typically, the number of sequences generated by iterating through the possible values ​​of k and l is sufficient to generate A, so it is not necessary to iterate through the possible values ​​of λ.

[0232] Understandably, in other examples, the value of λ can also be predefined or preconfigured.

[0233] For example, if λ is 1, the initial value of k (for network device configuration or indication) is 0, and the initial value of l is 0, then the sequence in the preamble set includes:

[0234] The first sequence: l = 0, k = 0, s 1,0,0 (n)=s1[(n+0)mod N],n=0,1,…,N-1;

[0235] Second sequence: l = 0, k = 1, s 1,0,1 (n)=s1[(n+Δ T [)mod N], n=0,1,…,N-1;

[0236] The third sequence: l = 0, k = 2, s 1,0,2 (n)=s1[(n+2Δ T [)mod N], n=0,1,…,N-1;

[0237] And so on;

[0238] No. (assumption) There are fewer than A sequences: l = 0,

[0239] No. A sequence: l = 1,

[0240] No. A sequence: l = 1,

[0241] No. A sequence: l = 1, k = 2,

[0242] This process continues until A sequences are obtained. Sequences with the same λ and l values ​​but different k values ​​are cyclic shifts of each other; for example, sequences 1 to... Different sequences within a sequence are cyclic shifts of each other.

[0243] In the above example, in a specific implementation, assuming the terminal device determines that the values ​​of traversal l are {0, 1, 2}, resulting in A sequences, then the terminal device can store the phase-shifted sequence s. 1,0,k (n), s 1,1,k (n) and s 1,2,k (n): s 1,0,k (n)=s1[(n+kΔ T [)mod N], n=0,1,…,N-1

[0244] Furthermore, when a terminal device needs to initiate random access, the terminal device can select from s 1,0,k (n), s 1,1,k (n) and s 1,2,k Randomly select a sequence from (n), for example, select a sequence s. 1,1,k (n); Further, the terminal device randomly selects a value k, assuming the selected k value is 1, then the terminal device can obtain the sequence s. 1,1,1 (n), and according to the sequence s 1,1,1 (n) Generates a random access signal. Where, sequence s 1,1,1 (n) is the preamble selected by the terminal device from the preamble set.

[0245] In other words, the terminal device can pre-store the phase offset sequence and, when random access needs to be initiated, select a phase offset sequence for cyclic shifting. Thus, by pre-stored the phase offset sequence, computational complexity can be reduced, while storage overhead is relatively large.

[0246] ② As another example of implementation method 1 (referred to as example 2), the first sequence can be obtained by first cyclically shifting the second sequence and then performing a phase shift.

[0247] For example, let the first sequence be s. λ,k,l (n), sλ,k,l (n) satisfies the following formula 3:

[0248] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F This indicates the value of the phase offset.

[0249] Alternatively, by expanding Equation 3 through calculation, we can obtain s λ,k,l (n) satisfies the following formula 4:

[0250] In other words, Formula 3 and Formula 4 are equivalent formulas.

[0251] Taking the first signal as a random access signal as an example, the terminal device can first determine the preamble set, then select a sequence (such as the first sequence) from the preamble set, and generate a random access signal based on the first sequence. When the first sequence satisfies the above formula 3 (or formula 4), as a possible implementation, the network device can configure or indicate the initial values ​​of λ, k, and l, for example, the initial values ​​of λ, k, and l are λ0, k0, and 0l, respectively; correspondingly, the terminal device determines the sequence based on the initial values ​​of λ, k, and l. Furthermore, the terminal device first iterates through the values ​​of k based on the initial value of k, generating A (for example, A is greater than or equal to 64) sequences; if the number of sequences generated by iterating through the values ​​of k is less than A, then it iterates through the values ​​of l based on the initial value of l; if the number of sequences generated by iterating through the values ​​of k and l is less than A, then it iterates through the values ​​of λ based on the initial value of λ.

[0252] For example, if λ is 1, the initial value of k (configured or indicated by the network device) is 0, and the initial value of l is 0, then the terminal device can obtain:

[0253] The first sequence: l = 0, k = 0, s 1,0,0 (n)=s1[(n+0)mod N],n=0,1,…,N-1;

[0254] Second sequence: l = 0, k = 1, s 1,0,1 (n)=s1[(n+Δ T [)mod N], n=0,1,…,N-1;

[0255] The third sequence: l = 0, k = 2, s 1,0,2 (n)=s1[(n+2Δ T [)mod N], n=0,1,…,N-1;

[0256] And so on;

[0257] No. (assumption) There are fewer than A sequences: l = 0,

[0258] No. A sequence: l = 1,

[0259] No. A sequence: l = 1,

[0260] No. A sequence: l = 1,

[0261] This process continues until A sequences are obtained. Sequences with the same λ and l values ​​but different k values ​​are cyclic shifts of each other (different from each other by only a constant phase), for example, sequences 1 to... Different sequences within a sequence are cyclic shifts of each other.

[0262] For example, when a terminal device needs to initiate random access, it can select the values ​​of l and k, and calculate the corresponding sequence based on the selected values ​​of l and k. For instance, if the terminal device selects a value of 2 for l and a value of 0 for k, it can substitute the values ​​of l and k into formula 3 or formula 4 to calculate s. 1,2,0 (n). It's understandable that if we iterate through the values ​​of l... And by iterating through the values ​​of k ({0, 1, 2}), we can obtain A sequences. Therefore, the value of l selected by the terminal device is... One of them, where the value of k selected by the terminal device is one of {0, 1, 2}.

[0263] Thus, since there is no need to pre-store the sequence, the storage overhead of the terminal device is small, but the computational complexity is relatively large.

[0264] ③ As another example of implementation method 1 (referred to as Example 3), the first sequence can be obtained from the fourth sequence. For example, considering that the constant term does not affect the sequence properties, such as sequence capacity, fuzzy function, detection complexity, etc., the first sequence can be obtained by removing the constant term from the fourth sequence. The fourth sequence is obtained by phase shifting and cyclic shifting of the second sequence. For example, the fourth sequence is obtained by first cyclic shifting the second sequence and then performing a phase shift (see Example 1); or, the fourth sequence is obtained by first cyclic shifting the second sequence and then performing a phase shift (see Example 2). That is to say, the first sequence is obtained by performing phase shifting and cyclic shifting on the second sequence and removing the constant phase, i.e., the first sequence does not contain a constant phase.

[0265] For example, the fourth sequence is denoted as satisfy:

[0266] or,

[0267] The first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies the following formula 5:

[0268] Where N represents the length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}.

[0269] Taking the first signal as a random access signal as an example, the terminal device can first determine the preamble set, then select a sequence (such as the first sequence) from the preamble set, and generate a random access signal based on the first sequence. When the first sequence satisfies the above formula 5, as a possible implementation, the network device can configure or indicate the initial values ​​of λ, k, and l, for example, the initial values ​​of λ, k, and l are λ0, k0, and 0l, respectively; correspondingly, the terminal device determines the sequence based on the initial values ​​of λ, k, and l. Furthermore, the terminal device first iterates through the values ​​of k based on the initial value of k, generating A (for example, A is greater than or equal to 64) sequences; if the number of sequences generated by iterating through the values ​​of k is less than A, then it iterates through the values ​​of l based on the initial value of l; if the number of sequences generated by iterating through the values ​​of k and l is less than A, then it iterates through the values ​​of λ based on the initial value of λ.

[0270] For example, when a terminal device needs to initiate random access, it can choose the values ​​of l and k, and calculate the corresponding sequence based on the selected values ​​of l and k. Thus, since there is no need to pre-store the sequence, the terminal device has lower storage overhead, but relatively higher computational complexity.

[0271] As can be seen from Examples 1 to 3 above, the cubic coefficients of the first sequence are the same as those of the second sequence. The quadratic coefficients of the first sequence are associated with the maximum round-trip time (RTD), and the linear coefficients of the first sequence are associated with both the RTD and the maximum Doppler shift. Furthermore, in Examples 1 to 3, λ is the index of the cubic coefficients, k is the index of the quadratic coefficients, and l is the index of the linear coefficients.

[0272] In implementation method 1, the first sequence is a sequence mapped from time-domain resources. The terminal device generates the first signal based on the first sequence, which can mean: the terminal device performs DFT processing on the first sequence to obtain a third sequence; then maps the elements of the third sequence onto frequency-domain resources and performs inverse Fourier transform processing to generate the first signal. The steps described here are only some possible steps; in specific implementations, other steps may also be included, without limitation. For example, the first signal is denoted as x(t), and x(t) satisfies:

[0273] Where t represents the time variable, m represents the subcarrier index, and T CP The duration of the cyclic prefix is ​​indicated by T, which represents the duration of the OFDM symbol.

[0274] Furthermore, since the first sequence in implementation method 1 is a time-domain resource mapping sequence, the first signal has the characteristic of constant modulus in the time domain, which facilitates ensuring a low peak-to-average power ratio (PAPR). Typically, random access signals require a low PAPR; for example, a low PAPR random access signal can effectively reduce the power consumption of terminal equipment. Therefore, when the first signal is a random access signal, the first sequence can be a time-domain resource mapping sequence.

[0275] (2) Implementation Method 2

[0276] In implementation method 2, the value of the cyclic shift can be an integer multiple of the maximum Doppler frequency shift, and the value of the phase offset can be an integer multiple of the maximum round-trip time. The maximum round-trip time and / or the maximum Doppler frequency shift are cell-related parameters, which can be configured by the network equipment or indicated to the terminal equipment.

[0277] ① As an example of implementation method 2 (referred to as example 4), the first sequence can be obtained by first phase shifting the second sequence and then performing a cyclic shift.

[0278] For example, let the first sequence be s. λ,k,l (n), s λ,k,l (n) satisfies the following formula 6:

[0279] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T This indicates the value of the phase offset.

[0280] Alternatively, by expanding Equation 6 through calculation, s can be obtained. λ,k,l (n) satisfies the following formula 7:

[0281] In other words, Formula 6 and Formula 7 are equivalent formulas.

[0282] Taking the first signal as a random access signal as an example, the terminal device can first determine the preamble set, then select a sequence (such as the first sequence) from the preamble set, and generate a random access signal based on the first sequence. When the first sequence satisfies the above formula 6 (or formula 7), as a possible implementation, the network device can configure or indicate the initial values ​​of λ, k, and l, for example, the initial values ​​of λ, k, and l are λ0, k0, and 0l, respectively; correspondingly, the terminal device determines the sequence based on the initial values ​​of λ, k, and l. Furthermore, the terminal device first iterates through the possible values ​​of k based on the initial value of k, generating A sequences (e.g., A is greater than or equal to 64). If the number of sequences generated by iterating through the possible values ​​of k is less than A, then it iterates through the possible values ​​of l based on the initial value of l. If the number of sequences generated by iterating through the possible values ​​of k and l is less than A, then it iterates through the possible values ​​of λ based on the initial value of λ. See Example 1 for a detailed description.

[0283] Among them, sequences with the same λ and l values ​​but different k values ​​in A sequences are cyclic shifts of each other (different from each other by only a constant phase).

[0284] For example, in a specific implementation, the terminal device can pre-store a sequence of phase offsets and, when random access needs to be initiated, select a sequence of phase offsets for cyclic shifting. In this way, by pre-storing the sequence of phase offsets, the computational complexity can be reduced, while the storage overhead is relatively large.

[0285] ② As another example of implementation method 2 (referred to as example 5), the first sequence can be obtained by first cyclically shifting the second sequence and then performing a phase shift.

[0286] For example, let the first sequence be s. λ,k,l (n), s λ,k,l (n) satisfies the following formula 8:

[0287] Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T This indicates the value of the phase offset.

[0288] Alternatively, by expanding Equation 8 through calculation, s can be obtained. λ,k,l (n) satisfies the following formula 9:

[0289] In other words, Formula 8 and Formula 9 are equivalent formulas.

[0290] Taking the first signal as a random access signal as an example, the terminal device can first determine the preamble set, then select a sequence (such as the first sequence) from the preamble set, and generate a random access signal based on the first sequence. When the first sequence satisfies the above formula 3 (or formula 4), as a possible implementation, the network device can configure or indicate the initial values ​​of λ, k, and l, for example, the initial values ​​of λ, k, and l are λ0, k0, and 0l, respectively; correspondingly, the terminal device determines the sequence based on the initial values ​​of λ, k, and l. Furthermore, the terminal device first iterates through the possible values ​​of k based on the initial value of k, generating A sequences (e.g., A is greater than or equal to 64). If the number of sequences generated by iterating through the possible values ​​of k is less than A, then it iterates through the possible values ​​of l based on the initial value of l. If the number of sequences generated by iterating through the possible values ​​of k and l is less than A, then it iterates through the possible values ​​of λ based on the initial value of λ. See Example 2 for a detailed description.

[0291] In this context, sequences with the same λ and l values ​​but different k values ​​among the A sequences are cyclic shifts of each other.

[0292] For example, when a terminal device needs to initiate random access, it can choose the values ​​of l and k, and calculate the corresponding sequence based on the selected values ​​of l and k. Thus, since there is no need to pre-store the sequence, the terminal device has lower storage overhead, but relatively higher computational complexity.

[0293] ③ As another example of implementation method 2 (referred to as Example 6), the first sequence can be obtained from the fifth sequence, for example, the first sequence is obtained by removing the constant term from the fifth sequence. The fifth sequence is obtained by phase shifting and cyclic shifting of the second sequence. For example, the fifth sequence is obtained by first cyclic shifting the second sequence and then performing a phase shift (see Example 4); or, the fifth sequence is obtained by first cyclic shifting the second sequence and then performing a phase shift (see Example 5). That is to say, the first sequence is obtained by performing phase shifting and cyclic shifting on the second sequence and removing the constant phase, i.e., the first sequence does not contain a constant phase.

[0294] For example, the fifth sequence is denoted as satisfy:

[0295] or,

[0296] The first sequence is denoted as s. λ,k,l (n), s λ,k,l (n) satisfies the following formula 10:

[0297] Where N represents the length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of phase offset is represented by λ∈{1,2,…,N-1}.

[0298] Taking the first signal as a random access signal as an example, the terminal device can first determine the preamble set, then select a sequence (such as the first sequence) from the preamble set, and generate a random access signal based on the first sequence. When the first sequence satisfies the above formula 5, as a possible implementation, the network device can configure or indicate the initial values ​​of λ, k, and l, for example, the initial values ​​of λ, k, and l are λ0, k0, and 0l, respectively; correspondingly, the terminal device determines the sequence based on the initial values ​​of λ, k, and l. Furthermore, the terminal device first iterates through the values ​​of k based on the initial value of k, generating A (for example, A is greater than or equal to 64) sequences; if the number of sequences generated by iterating through the values ​​of k is less than A, then it iterates through the values ​​of l based on the initial value of l; if the number of sequences generated by iterating through the values ​​of k and l is less than A, then it iterates through the values ​​of λ based on the initial value of λ.

[0299] For example, when a terminal device needs to initiate random access, it can choose the values ​​of l and k, and calculate the corresponding sequence based on the selected values ​​of l and k. Thus, since there is no need to pre-store the sequence, the terminal device has lower storage overhead, but relatively higher computational complexity.

[0300] As can be seen from Examples 4 to 6 above, the cubic coefficients of the first sequence are the same as those of the second sequence. The quadratic coefficients of the first sequence are associated with the maximum Doppler shift, and the linear coefficients of the first sequence are associated with the maximum round-trip time and the maximum Doppler shift. Furthermore, in Examples 1 to 3, λ is the index of the cubic coefficients, k is the index of the quadratic coefficients, and l is the index of the linear coefficients.

[0301] In implementation method 2, the first sequence is a sequence mapped from frequency domain resources. The terminal device generates the first signal based on the first sequence, which can mean that the terminal device maps the elements of the first sequence to frequency domain resources and performs an inverse Fourier transform to generate the first signal. The steps described here are only some possible steps; in specific implementations, other steps may also be included, without limitation. For example, the first signal is denoted as x(t), and x(t) satisfies:

[0302] Where t represents the time variable, m represents the subcarrier index, and T CP The duration of the cyclic prefix is ​​indicated by T, which represents the duration of the OFDM symbol.

[0303] Furthermore, since the first sequence in implementation method 2 is a frequency domain resource-mapped sequence, the first signal has the characteristic of constant modulus in the frequency domain, which facilitates ensuring ideal autocorrelation. Typically, the reference signal requires ideal autocorrelation; for example, an ideally autocorrelated reference signal allows the receiver to accurately detect the signal's start position, period, etc. Therefore, when the first signal is a reference signal, the first sequence can be a frequency domain resource-mapped sequence.

[0304] It should be understood that the embodiments in this application are described using the example of "N being a prime number". In other examples, N may not be a prime number. For example, when the first signal is a reference signal, N may not be a prime number. When N is not a prime number, the second sequence can be expressed as the following formula 11:

[0305] Accordingly, taking Example 4 in Implementation Method 2 above as an example, the first sequence can be represented as:

[0306] Where P is the largest prime number not exceeding N, s λ (n) represents the second sequence (i.e., formula 11), λ∈{1,2,…,P-1}, For other details, please refer to the relevant descriptions when N is a prime number.

[0307] S802, the terminal device sends a first signal; correspondingly, the network device receives the first signal.

[0308] For example, the first signal may be generated by the baseband chip of the terminal device. Sending the first signal by the terminal device includes the baseband chip of the terminal device sending the first signal to the radio frequency chip of the terminal device. Sending the first signal by the terminal device also includes the radio frequency chip of the terminal device sending the first signal to the network device.

[0309] S803, the network device obtains the first sequence based on the first signal.

[0310] For example, in implementation 1 above, after receiving the first signal, the network device performs an FFT transformation to the frequency domain and demaps it to obtain a frequency domain signal. Furthermore, for the local sequence S1, the network device performs a DFT transformation on sequence S1 to the frequency domain (or, the network device can directly save the frequency domain signal after the DFT transformation), and multiplies the received frequency domain signal with the conjugate of the local frequency domain signal (or, the network device can directly save the signal after the conjugate processing of the local frequency domain signal, and then calculate the inner product between the received frequency domain signal and the conjugate processed signal), performs an IDFT transformation to the time domain, and obtains the correlation function between the received signal and the local signal. If the correlation function exceeds a threshold, the first sequence is considered to have been detected.

[0311] Taking the first signal as a random access signal as an example, during PRACH detection, the number of complex multiplications in PDP detection is: M represents the number of combinations of cubic and linear coefficient indices. For example, taking Example 1, if we iterate through the values ​​of l ({0,1,2}) to obtain A sequences (excluding the values ​​of λ, meaning the λ values ​​are the same in all A sequences), then M = 3. If we iterate through the values ​​of λ ({1,2}) and l ({0,1,2}) to obtain A sequences, then M = 6. It can be seen that the detection complexity of the cubic polynomial exponent sequence provided in this embodiment is comparable to that of the ZC sequence.

[0312] Regarding implementation method 2 above, after receiving the first signal, the network device performs an FFT transformation to the frequency domain and demaps it to obtain the frequency domain signal. Furthermore, for the local sequence S1, the network device performs a conjugate multiplication of the received frequency domain signal and the local frequency domain signal (i.e., the local sequence S1) (or, the network device can directly save the signal after conjugate processing of the local sequence S1 and then calculate the inner product between the received frequency domain signal and the conjugate processed signal), performs an IDFT transformation to the time domain, and obtains the correlation function between the received signal and the local signal. If the correlation function exceeds a threshold, the first sequence is considered to have been detected.

[0313] It should be understood that the expressions for cubic polynomial exponent sequences given in the embodiments of this application are merely some possible examples. Modifications made based on these examples (such as shifting the coefficients of the cubic, quadratic, or linear terms of the entire cubic polynomial exponent sequence, or shifting the constant term of each generated sequence) will not change the sequence properties (such as large capacity, low ambiguity, and low detection complexity), and are readily available to those skilled in the art, and are also within the scope of protection of this invention. For example, a cubic polynomial exponent sequence... If N is a prime number, and assuming the coefficient of the cubic term is shifted globally, the shifted sequence can be:

[0314] Regarding the above embodiments, it is understood that:

[0315] (1) In this application, “predefined” usually refers to information that is defined by the standard, does not require configuration by other devices, and is recorded / written in advance in the hardware and / or software of the terminal device or network device itself, or can be understood as information that cannot be changed by the network device or terminal device.

[0316] In this application, "pre-configuration" can refer to the server sending relevant information to network devices or terminal devices; alternatively, it can refer to defining the relevant information and pre-writing it into the network devices or terminal devices. This application does not limit the specific method used. Furthermore, the relevant information can be changed or updated.

[0317] (2) In the embodiments of this application, unless otherwise specified or in case of logical conflict, the terms and / or descriptions in different examples or implementations are consistent and can be referenced by each other. The technical features in different examples or implementations can be combined to form new embodiments according to their inherent logical relationships. In addition, different implementations or different examples can be referenced or referenced by each other.

[0318] (3) The various numerical designations used in this application are merely for descriptive convenience and are not intended to limit the scope of this application. The step numbers in the above flowcharts are only examples of the execution process and do not constitute a restriction on the order of execution of the steps. That is, the size of each step number does not imply the order of execution, and the execution order of each step should be determined by its function and internal logic. In addition, not all steps shown in the flowcharts are mandatory steps, and some steps can be added or deleted based on actual needs.

[0319] The above mainly describes the solution provided by the embodiments of this application from the perspective of the interaction between the first communication device and the second communication device. It is understood that, in order to achieve the above functions, the first communication device and the second communication device may include hardware structures and / or software modules corresponding to the execution of 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.

[0320] In this application embodiment, the first communication device and the second communication device can be divided into functional units according to the above method example. 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.

[0321] In the case of using integrated units, FIG9 shows a possible exemplary block diagram of the device involved in the embodiments of this application. As shown in FIG9, the device 900 may include a processing unit 902 and a communication unit 903. The processing unit 902 is used to control and manage the operation of the device 900. The communication unit 903 is used to support communication between the device 900 and other devices. Optionally, the communication unit 903 is also called a transceiver unit, and may include a receiving unit and / or a sending unit, respectively used to perform receiving and sending operations. The device 900 may also include a storage unit 901 for storing the program code and / or data of the device 900.

[0322] (1) The device 900 can be the first communication device in the above embodiments. The processing unit 902 can support the device 900 in performing the actions of the first communication device in the above method embodiments. Alternatively, the processing unit 902 mainly performs the internal actions of the first communication device in the method embodiments, and the communication unit 903 can support communication between the device 900 and other devices.

[0323] For example, in one embodiment, the processing unit 902 is used to: generate a first signal according to a first sequence; the communication unit 903 is used to: send the first signal; wherein, the first sequence is a cubic polynomial exponential sequence, the first sequence is obtained according to the phase shift and cyclic shift of a second sequence, and the second sequence is a base sequence.

[0324] (2) The device 900 can be the second communication device in the above embodiments. The processing unit 902 can support the device 900 in performing the actions of the second communication device in the above method embodiments. Alternatively, the processing unit 902 mainly performs the internal actions of the second communication device in the method embodiments, and the communication unit 903 can support communication between the device 900 and other devices.

[0325] For example, in one embodiment, the communication unit 903 receives a first signal; the processing unit 902 is configured to obtain a first sequence based on the first signal; wherein the first sequence is a cubic polynomial exponential sequence, the first sequence is obtained based on the phase shift and cyclic shift of a second sequence, and the second sequence is a base sequence.

[0326] It should be understood that the division of units in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, all units in the device can be implemented entirely through software calls from processing elements; all units can be implemented entirely in hardware; or some units can be implemented through software calls from processing elements, while others are implemented in hardware. For example, each unit can be a separate processing element, or it can be integrated into a chip within the device. Alternatively, it can be stored as a program in memory, called and executed by a processing element of the device. Moreover, these units can be fully or partially integrated together, or implemented independently. The processing element here can also be called a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, the operations or units described above can be implemented through integrated logic circuits in the processor element or through software calls from processing elements.

[0327] In one example, a unit in any of the above devices can be one or more integrated circuits configured to implement the methods described above, such as: one or more application-specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these forms of integrated circuits. As another example, when a unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a processor, such as a central processing unit (CPU), or other processor capable of calling programs. Furthermore, these units can be integrated together and implemented as a System-on-a-Chip (SoC).

[0328] The receiving unit described above is an interface circuit of the device, used to receive signals from other devices. For example, when the device is implemented as a chip, the receiving unit is an interface circuit for the chip to receive signals from other chips or devices. The transmitting unit described above is an interface circuit of the device, used to transmit signals to other devices. For example, when the device is implemented as a chip, the transmitting unit is an interface circuit for the chip to transmit signals to other chips or devices.

[0329] Based on the above embodiments, this application also provides a communication device. Referring to FIG10, the communication device 1000 may include one or more processors 1001. Optionally, the communication device 1000 may further include a memory 1002, which may be disposed inside or outside the communication device 1000. It is understood that FIG10 only shows the main components of the communication device, and the communication device may further include a transceiver (not shown in the figure).

[0330] Specifically, processor 1001 may be a CPU, a network processor (NP), or a combination of a CPU and an NP. Processor 1001 may further include a hardware chip. The aforementioned hardware chip may be an ASIC, a programmable logic device (PLD), or a combination thereof. The aforementioned PLD may be a complex programmable logic device (CPLD), an FPGA, generic array logic (GAL), or any combination thereof.

[0331] The processor 1001 and memory 1002 are interconnected. Optionally, the processor 1001 and memory 1002 are interconnected via bus 1003; bus 1003 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, only one thick line is used in Figure 10, but this does not indicate that there is only one bus or one type of bus.

[0332] In one alternative implementation, memory 1002 is used to store programs, etc. Specifically, the program may include program code, which includes computer operation instructions. Memory 1002 may include RAM, and may also include non-volatile memory, such as one or more disk storage devices. Processor 1001 executes the application program stored in memory 1002 to implement the above-mentioned functions, thereby realizing the functions of communication device 1000.

[0333] For example, the communication device 1000 may be the first communication device or the second communication device in the above embodiments.

[0334] In one embodiment, when the communication device 1000 performs the functions of the first communication device in the above method embodiment, the transceiver can perform the transmit and receive operations executed by the first communication device in the above method embodiment; the processor 1001 can perform other operations besides the transmit and receive operations executed by the first communication device in the above method embodiment. Specific details can be found in the relevant descriptions in the above embodiments, and will not be elaborated upon here.

[0335] In one embodiment, when the communication device 1000 performs the functions of the second communication device in the above method embodiment, the transceiver can perform the transmit and receive operations executed by the second communication device in the above method embodiment; the processor 1001 can perform other operations besides the transmit and receive operations executed by the second communication device in the above method embodiment. Specific details can be found in the relevant descriptions in the above embodiments, and will not be elaborated upon here.

[0336] The terms "system" and "network" in this application embodiment are used interchangeably. "At least one" refers to one or more, and "multiple" 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 items, including any combination of single or plural items. For example, "at least one of A, B, and C" includes A, B, C, AB, AC, BC, or ABC. And, unless otherwise specified, the ordinal numbers such as "first" and "second" mentioned in this application embodiment are used to distinguish multiple objects and are not used to limit the order, sequence, priority, or importance of multiple objects.

[0337] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0338] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0339] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0340] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

Claims

1. A communication method, characterized in that, The method includes: Generate a first signal based on the first sequence; Send the first signal; The first sequence is a cubic polynomial exponential sequence, which is obtained by phase shift and cyclic shift of the second sequence.

2. A communication method, characterized in that, The method includes: Receive the first signal; Based on the first signal, a first sequence is obtained; The first sequence is a cubic polynomial exponential sequence, which is obtained by phase shift and cyclic shift of the second sequence.

3. The method according to claim 1 or 2, characterized in that, The second sequence is denoted as s λ (n), s λ (n) satisfies: Where N represents the sequence length of the second sequence, N is an integer greater than 1, and N is a prime number, λ∈{1,2,…,N-1}.

4. The method according to any one of claims 1 to 3, characterized in that, The value of the cyclic shift is an integer multiple of the maximum round-trip time, and the value of the phase shift is an integer multiple of the maximum Doppler frequency shift.

5. The method according to claim 4, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

6. The method according to claim 4, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

7. The method according to claim 4, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

8. The method according to claim 4, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

9. The method according to claim 4, characterized in that, The first sequence is obtained based on the phase shift and cyclic shift of the second sequence, including: The first sequence is obtained by phase shifting and cyclic shifting the second sequence, and removing the constant phase.

10. The method according to claim 9, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. T Indicates the value of the cyclic shift, lΔ F The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

11. The method according to any one of claims 4 to 10, characterized in that, The first sequence is denoted as s λ,k,l (n), n = 0, 1, ..., N-1, where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number; the first signal is denoted as x(t), and x(t) satisfies: Where t represents the time variable, m represents the subcarrier index, and T CP The duration of the cyclic prefix is ​​represented by T, which represents the duration of an OFDM symbol.

12. The method according to any one of claims 1 to 3, characterized in that, The cyclic shift is an integer multiple of the maximum Doppler frequency shift, and the phase offset is an integer multiple of the maximum round-trip time delay.

13. The method according to claim 12, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

14. The method according to claim 12, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

15. The method according to claim 12, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Among them, s λ (n) represents the second sequence, N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

16. The method according to claim 12, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

17. The method according to claim 12, characterized in that, The first sequence is obtained based on the phase shift and cyclic shift of the second sequence, including: The first sequence is obtained by phase shifting and cyclic shifting the second sequence, and removing the constant phase.

18. The method according to claim 17, characterized in that, The first sequence is denoted as s λ,k,l (n), s λ,k,l (n) satisfies: Where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number, Δ T Δ represents the maximum round-trip time. F kΔ represents the maximum Doppler frequency shift. F Indicates the value of the cyclic shift, lΔ T The value of the phase offset is λ∈{1,2,…,N-1}. This indicates rounding down to the nearest integer.

19. The method according to any one of claims 12 to 18, characterized in that, The first sequence is denoted as s λ,k,l (n), n = 0, 1, ..., N-1, where N represents the sequence length of the first sequence, N is an integer greater than 1, and N is a prime number; the first signal is denoted as x(t), and x(t) satisfies: Where t represents the time variable, m represents the subcarrier index, and T CP The duration of the cyclic prefix is ​​indicated by T, which represents the duration of the OFDM symbol.

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

21. A communication device, characterized in that, The device includes a processor coupled to a memory in which a computer program is stored; the processor is configured to invoke part or all of the computer program in the memory such that the method as described in any one of claims 1 to 19 is executed.

22. A communication system, characterized in that, The communication system includes a first communication device and a second communication device, wherein the first communication device is used to perform the method as described in claim 1, and the second communication device is used to perform the method as described in claim 2.

23. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when some or all of the computer program is executed by a computer, causes the method described in any one of claims 1 to 19 to be performed.

24. A computer program product, characterized in that, When the computer reads and executes the computer program product, the method described in any one of claims 1 to 19 is performed.

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