Communication Method, Communication Apparatus, and Communication System

Abstract

A communication method may include a first apparatus that obtains a cyclic shift sequence, where the cyclic shift sequence includes a delay domain cyclic shift and a Doppler cyclic shift; and outputs the cyclic shift sequence, where the cyclic shift sequence is used to generate a random access signal or a sensing signal.

Claims

1. A method comprising: performing a delay domain cyclic shift and a Doppler domain cyclic shift on a quadratic exponential sequence to obtain a quadratic exponential sequence set; obtaining a cyclic shift sequence, wherein the cyclic shift sequence is in the quadratic exponential sequence set and comprises a delay domain cyclic shift and a Doppler domain cyclic shift; and outputting the cyclic shift sequence.

2. (canceled)

3. The method of claim 1, wherein cyclic shift sequences with a same quadratic term coefficient in the quadratic exponential sequence set form a zero ambiguity zone, and wherein cyclic shift sequences with different quadratic term coefficients in the quadratic exponential sequence set form a low ambiguity zone.

4. The method of claim 1, wherein a discrete-time signal of the quadratic exponential sequence is:
s.sub.u,k,l(n)=e.sup.j[u(n+k.sup.T.sup.)(n+k.sup.T.sup.+1)+2nl.sup.F.sup.]/N,n=0,1, . . . ,N1, wherein s.sub.u,k,l(n) is the quadratic exponential sequence, wherein N represents a sequence length, wherein the sequence length is a composite number, wherein u represents a quadratic term coefficient, wherein the quadratic term coefficient comprises a prime factor of the sequence length, wherein k represents an index of the delay cyclic shift, wherein l represents an index of the Doppler cyclic shift, wherein .sub.T represents a preset maximum delay, and wherein .sub.F represents a preset maximum Doppler shift.

5. The method of claim 1, wherein a value of the sequence length is equal to a product of M mutually different prime numbers, wherein M is a positive integer, wherein the quadratic exponential sequence comprises sequences with the M mutually different prime numbers as quadratic term coefficients, wherein the quadratic exponential sequence set comprises G sequence sets based on separately performing delay domain cyclic shifts and Doppler domain cyclic shifts on the sequences with the M mutually different prime numbers as quadratic term coefficients, and wherein G is a positive integer.

6. The method of claim 4, wherein obtaining the cyclic shift sequence comprises determining the cyclic shift sequence based on the sequence length, the quadratic term coefficient, the preset maximum delay, and the preset maximum Doppler shift.

7. The method of claim 6, wherein the cyclic shift sequence is configured to generate a random access signal or a sensing signal.

8. A communication apparatus, comprising: at least one memory configured to store a computer program; and one or more processors coupled to the memory and configured to execute the computer program to cause the communication apparatus to: perform a delay domain cyclic shift and a Doppler domain cyclic shift on a quadratic exponential sequence to obtain a quadratic exponential sequence set; obtain a cyclic shift sequence, wherein the cyclic shift sequence is in the quadratic exponential sequence set and comprises a delay domain cyclic shift and a Doppler domain cyclic shift; and output the cyclic shift sequence.

9. (canceled)

10. The communication apparatus of claim 8, wherein cyclic shift sequences with a same quadratic term coefficient in the quadratic exponential sequence set form a zero ambiguity zone, and wherein cyclic shift sequences with different quadratic term coefficients in the quadratic exponential sequence set form a low ambiguity zone.

11. The communication apparatus of claim 8, wherein a discrete-time signal of the quadratic exponential sequence is:
s.sub.u,k,l(n)=e.sup.j[u(n+k.sup.T.sup.)(n+k.sup.T.sup.+1)+2nl.sup.F.sup.]/N,n=0,1, . . . ,N1, wherein s.sub.u,k,l(n) is the quadratic exponential sequence, wherein N represents a sequence length, wherein the sequence length is a composite number, wherein u represents a quadratic term coefficient, wherein the quadratic term coefficient comprises a prime factor of the sequence length, wherein k represents an index of the delay cyclic shift, wherein l represents an index of the Doppler cyclic shift, wherein .sub.T represents a preset maximum delay, and wherein .sub.F represents a preset maximum Doppler shift.

12. The communication apparatus of claim 8, wherein a value of the sequence length is equal to a product of M mutually different prime numbers, wherein M is a positive integer, wherein the quadratic exponential sequence comprises sequences with the M mutually different prime numbers as quadratic term coefficients, wherein the quadratic exponential sequence set comprises G sequence sets based on separately performing delay domain cyclic shifts and Doppler domain cyclic shifts on the sequences with the M mutually different prime numbers as quadratic term coefficients, and wherein G is a positive integer.

13. The communication apparatus of claim 11, wherein the one or more processors are further configured to execute the computer program to cause the communication apparatus to determine the cyclic shift sequence based on the sequence length, the quadratic term coefficient, the preset maximum delay, and the preset maximum Doppler shift.

14. The communication apparatus of claim 13, wherein the cyclic shift sequence is configured to generate a random access signal or a sensing signal.

15. A communication apparatus, comprising: at least one memory configured to store a computer program; and one or more processors coupled to the memory and configured to execute the computer program to cause the communication apparatus to: receive a cyclic shift sequence comprising a delay domain cyclic shift and a Doppler domain cyclic shift, wherein the cyclic shift sequence is in a quadratic exponential sequence set, and wherein the quadratic exponential sequence set is based on performing a delay domain cyclic shift and a Doppler domain cyclic shift on a quadratic exponential sequence; and process the cyclic shift sequence.

16. (canceled)

17. The communication apparatus of claim 15, wherein cyclic shift sequences with a same quadratic term coefficient in the quadratic exponential sequence set form a zero ambiguity zone, and wherein cyclic shift sequences with different quadratic term coefficients in the quadratic exponential sequence set form a low ambiguity zone.

18. The communication apparatus of claim 15, wherein a discrete-time signal of the quadratic exponential sequence is:
s.sub.u,k,l(n)=e.sup.j[u(n+k.sup.T.sup.)(n+k.sup.T.sup.+1)+2nl.sup.F.sup.]/N,n=0,1, . . . ,N1, wherein s.sub.u,k,l(n) is the quadratic exponential sequence, wherein N represents a sequence length, wherein the sequence length is a composite number, wherein u represents a quadratic term coefficient, wherein the quadratic term coefficient comprises a prime factor of the sequence length, wherein k represents an index of the delay cyclic shift, wherein l represents an index of the Doppler cyclic shift, wherein .sub.T represents a preset maximum delay, and wherein .sub.F represents a preset maximum Doppler shift.

19. The communication apparatus of claim 15, wherein a value of the sequence length is equal to a product of M mutually different prime numbers, wherein M is a positive integer, wherein the quadratic exponential sequence comprises sequences with the M mutually different prime numbers as quadratic term coefficients, wherein the quadratic exponential sequence set comprises G sequence sets based on separately performing delay domain cyclic shifts and Doppler domain cyclic shifts on the sequences with the M mutually different prime numbers as quadratic term coefficients, and wherein G is a positive integer.

20. The communication apparatus of claim 19, wherein when M is equal to 2, wherein the sequence length is equal to a first prime number multiplied by a second prime number, wherein the quadratic exponential sequence comprises a first sequence with the first prime number as a quadratic term coefficient and a second sequence with the second prime number as a quadratic term coefficient, and wherein the quadratic exponential sequence set comprises a first sequence set based on performing a delay domain cyclic shift and a Doppler domain cyclic shift on the first sequence with the first prime number as a quadratic term coefficient, and comprises a second sequence set based on performing a delay domain cyclic shift and a Doppler domain cyclic shift on the second sequence with the second prime number as a quadratic term coefficient.

21. The communication apparatus of claim 19, wherein when M is equal to 3, the sequence length is equal to a third prime number multiplied by a fourth prime number and multiplied by a fifth prime number, wherein the quadratic exponential sequence comprises a third sequence whose third prime number is a quadratic term coefficient, a fourth sequence whose fourth prime number is a quadratic term coefficient, and a fifth sequence whose fifth prime number is a quadratic term coefficient, and wherein the secondary index sequence set comprises a third sequence set based on cyclically shifting the third sequence whose third prime number is a quadratic term coefficient and a cyclic shift of a Doppler domain, a fourth sequence set based on cyclically shifting the fourth sequence whose fourth prime number is a quadratic term coefficient and a cyclic shift of a Doppler domain, and a fifth sequence set based on cyclic shift of a fifth sequence whose fifth prime number is a quadratic term coefficient and a cyclic shift of a Doppler domain.

22. The method of claim 5, wherein when M is equal to 2, the sequence length is equal to a first prime number multiplied by a second prime number, wherein the quadratic exponential sequence comprises a first sequence with the first prime number being a quadratic coefficient and a second sequence with the second prime number being a quadratic coefficient, and wherein the secondary index sequence set comprises a first sequence set obtained after cyclic shift of a first sequence whose first prime number is a quadratic coefficient and a first sequence set obtained after cyclic shift of a Doppler domain and comprises a second sequence set based on cyclically shifting the second sequence whose second prime number is a quadratic coefficient and a cyclic shift of a delay domain and a cyclic shift of a Doppler domain.

23. The method of claim 5, wherein when M is equal to 3, the sequence length is equal to a third prime number multiplied by a fourth prime number and multiplied by a fifth prime number, wherein the quadratic exponential sequence comprises a third sequence whose third prime number is a quadratic term coefficient, a fourth sequence whose fourth prime number is a quadratic term coefficient, and a fifth sequence whose fifth prime number is a quadratic term coefficient, and wherein the secondary index sequence set comprises a third sequence set based on cyclically shifting the third sequence whose third prime number is a quadratic term coefficient and a cyclic shift of a Doppler domain, a fourth sequence set based on cyclically shifting the fourth sequence whose fourth prime number is a quadratic term coefficient and a cyclic shift of a Doppler domain, and a fifth sequence set based on cyclic shift of a fifth sequence whose fifth prime number is a quadratic term coefficient and a cyclic shift of a Doppler domain.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0090] The following briefly describes accompanying drawings used in describing embodiments.

[0091] FIG. 1 is a diagram of a structure of a communication system according to an embodiment of this disclosure;

[0092] FIG. 2 is a diagram of simulation of an ambiguity function of a Zadoff-Chu sequence using a correlation property according to an embodiment of this disclosure;

[0093] FIG. 3 is a diagram of simulation of an ambiguity function of an extended Zadoff-Chu sequence using an ambiguity property according to an embodiment of this disclosure;

[0094] FIG. 4 is a schematic flowchart of a communication method according to an embodiment of this disclosure;

[0095] FIG. 5 is a diagram of an ambiguity function of a cyclic shift sequence according to an embodiment of this disclosure;

[0096] FIG. 6A and FIG. 6B are a diagram of simulation of an ambiguity function of a cyclic shift sequence according to an embodiment of this disclosure;

[0097] FIG. 7A is a diagram of side lobes appearing within a zero ambiguity zone according to an embodiment of this disclosure;

[0098] FIG. 7B is a diagram of a receive window function according to an embodiment of this disclosure;

[0099] FIG. 7C to FIG. 7E are a diagram of suppressing a Doppler side lobe by using different roll-off factors according to an embodiment of this disclosure;

[0100] FIG. 7F and FIG. 7G are a diagram of comparison between ambiguity functions of two sequences according to an embodiment of this disclosure;

[0101] FIG. 8A and FIG. 8B are a diagram of an ambiguity function of a cyclic shift sequence whose sequence length is a product of two prime numbers according to an embodiment of this disclosure;

[0102] FIG. 9A to FIG. 9C are a diagram of an ambiguity function of a cyclic shift sequence whose sequence length is a product of three prime numbers according to an embodiment of this disclosure;

[0103] FIG. 10 is a diagram of a structure of a communication apparatus according to an embodiment of this disclosure; and

[0104] FIG. 11 is a diagram of a structure of a communication apparatus according to an embodiment of this disclosure.

DESCRIPTION OF EMBODIMENTS

[0105] The following describes embodiments of this disclosure with reference to the accompanying drawings in embodiments of this disclosure.

[0106] The technical solutions provided in this disclosure may be applied to various communication systems, for example, a 5th generation (5G) mobile communication system like an LTE system, an LTE frequency-division duplex (FDD) system, an LTE time-division duplex (TDD) system, and a NR system, and a system evolved after 5G, for example, a 6th generation (6G) mobile communication system or an integrated sensing and communication system.

[0107] The technical solutions provided in this disclosure may be further applied to machine-type communication (MTC), an LTE technology for machine-to-machine communication (LTE-M), a device-to-device (D2D) network, a machine-to-machine (M2M) network, an internet of things (IoT) network, or another network. The IoT network may include, for example, an internet of vehicles. Communication manners in an internet of vehicles system are collectively referred to as vehicle-to-X (V2X, where X can stand for anything). For example, the V2X may include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-network (V2N) communication, or the like. A V2X communication system is a sidelink (SL) transmission technology based on D2D communication.

[0108] To better understand a communication method, an apparatus, and a system provided in embodiments of this disclosure, the following first describes the communication system used in embodiments of this disclosure. FIG. 1 is a diagram of a structure of a communication system 100 according to an embodiment of this disclosure. The communication system 100 includes a network device 111, a network device 112, a terminal device 101, a terminal device 102, a terminal device 103, and a terminal device 104. It should be understood that the communication system 100 may include more or fewer network devices and more or fewer terminal devices. The network device and the terminal device may be hardware, or software obtained through function division, or a combination thereof. The network device 111 and the network device 112 may communicate with the terminal device 101 to the terminal device 104 via another device or network element. In the system, the network device 111 and the network device 112 may perform data transmission with the plurality of terminal devices: the terminal device 101 to the terminal device 104. For example, the network device 111 sends downlink data to the terminal device 101 to the terminal device 104, and the terminal device 101 to the terminal device 104 may also send uplink data to the network device 111. In addition, the terminal device 101, the terminal device 102, the terminal device 103, and the terminal device 104 may also form a communication system. In the system, the network device 111 may send downlink data to the terminal device 101 and the terminal device 104, and the terminal device 104 sends the downlink data to the terminal device 102 or the terminal device 103. The terminal device 101 and the terminal device 104 may also send uplink data to the network device 111. The method in embodiments of this disclosure may be applied to the communication system 100 shown in FIG. 1.

[0109] (1) The terminal device includes a device that provides voice and/or data connectivity for a user. For example, the terminal device may include a processing device connected to a wireless modem. The terminal device may communicate with a core network via a radio access network (RAN), and exchange a voice or data with the RAN, or exchange a voice and data with the RAN. The terminal device may include a handheld terminal, a notebook computer, a subscriber unit, a cellular phone, a smartphone, a wireless data card, a personal digital assistant (PDA) computer, a tablet computer, a palmtop computer, a wireless modem (modem), a handheld device (handheld), a laptop computer, a cordless telephone (cordless phone) or a wireless local loop (WLL) station, a machine type communication (MTC) terminal, a wearable device (for example, a smart watch, a smart band, and a pedometer), a vehicle-mounted device (for example, a car, a bicycle, an electric vehicle, an airplane, a ship, a train, and a high-speed railway), a V2X terminal device, a machine-to-machine/machine type communication (M2M/MTC) terminal device, an IoT terminal device, a light terminal device (light UE), a reduced capability terminal device (REDCAP UE), a point-of-sale (POS) machine, a customer-premises equipment (CPE), a mobile internet device (MID), a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a smart home device (for example, a refrigerator, a television, an air conditioner, or an electric meter), a smart robot, a workshop device, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a flight device (for example, a smart robot, a hot air balloon, an uncrewed aerial vehicle, or an airplane), or another device that can access a network.

[0110] In embodiments of this disclosure, the terminal device may further include a relay. Alternatively, it is understood as that any device that can perform data communication with a network device (for example, a base station) may be considered as a terminal device.

[0111] In embodiments of this disclosure, an apparatus configured to implement a function of the terminal device may be a terminal device, or may be an apparatus that can support the terminal device in implementing the function, for example, a chip system. The apparatus may be mounted in the terminal device. In embodiments of this disclosure, the chip system may include a chip, or may include a chip and another discrete component. In the technical solutions provided in embodiments of this disclosure, an example in which the apparatus configured to implement the function of the terminal is a terminal device is used for describing the technical solutions provided in embodiments of this disclosure.

[0112] (2) The network device is a node in a RAN, and may also be referred to as an access network device, or may also be referred to as a RAN node (or device). The network device is configured to help the terminal implement radio access. A plurality of network devices in the communication system 100 may be nodes of a same type, or may be nodes of different types.

[0113] In a possible scenario, the network device may be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next generation NodeB (gNB), a base station in a 6G mobile communication system, a base station or a satellite in a future mobile communication system, an access node, an integrated access and backhaul (IAB) node, a transmission point (TP), or a mobile switching center in a Wi-Fi system, and a device that functions as a base station in D2D, V2X, M2M, or uncrewed aerial vehicle communication, or the like. The network device may be a macro base station, a micro base station, an indoor base station, a relay node, a donor node, or a radio controller in a CRAN scenario. The network device may alternatively be a device that functions as a base station in D2D communication, internet of vehicles communication, uncrewed aerial vehicle communication, or machine communication. Optionally, the network device may alternatively be a server, a wearable device, a vehicle, a vehicle-mounted device, or the like. For example, an access network device in a V2X technology may be a road side unit (RSU).

[0114] In another possible scenario, a plurality of network devices collaborates to assist the terminal in implementing radio access, and different network devices separately implement a part of functions of the base station. For example, the network device may be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), a radio unit (RU), or the like. The CU and the DU may be separately arranged, or may be included in a same network element, for example, a baseband unit (BBU). The RU may be included in a radio frequency device or a radio frequency unit, for example, included in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It may be understood that the network device may be a CU node, a DU node, or a device including the CU node and the DU node. In addition, the CU may be classified as a network device in an access network RAN, or the CU may be classified as a network device in a core network (CN). This is not limited herein.

[0115] In different systems, the CU (or the CU-CP and the CU-UP), the DU, or the RU may alternatively have different names, but persons skilled in the art may understand meanings thereof. For example, in an ORAN system, the CU may also be referred to as an O-CU (open CU), the DU may also be referred to as an O-DU, the CU-CP may also be referred to as an O-CU-CP, the CU-UP may also be referred to as an O-CU-UP, and the RU may also be referred to as an O-RU. For ease of description, the CU, the CU-CP, the CU-UP, the DU, and the RU are used as examples for description in this disclosure. Any one of the CU (or the CU-CP and the CU-UP), the DU, and the RU in this disclosure may be implemented by using a software module, a hardware module, or a combination of the software module and the hardware module.

[0116] The network device may further include a CN device, which is a device in a CN that provides service support for the terminal device. The CN device may be an access and mobility management function (AMF) network element, a session management function (SMF) network element, a user plane function (UPF) network element, or the like, which are not listed one by one herein. The AMF network element may be responsible for access management and mobility management of the terminal device. The SMF network element may be responsible for session management, for example, session establishment of a user. The UPF network element may be a UPF entity, and is mainly responsible for connecting to an external network. It should be noted that the network element in this disclosure may also be referred to as an entity or a functional entity. For example, the AMF network element may also be referred to as an AMF entity or an AMF functional entity. For another example, the SMF network element may also be referred to as an SMF entity, an SMF functional entity, or the like.

[0117] In embodiments of this disclosure, an apparatus configured to implement a function of the network device may be a network device, or may be an apparatus that can support the network device in implementing the function, for example, a chip system. The apparatus may be mounted in the network device.

[0118] For ease of understanding, some concepts related to embodiments of this disclosure are described below for reference by using examples. Details are as follows.

[0119] 1. A Zadoff-Chu sequence, referred to as a ZC sequence for short, is a sequence generated through a phase change. The ZC sequence varies depending on whether a sequence length N.sub.ZC is an odd number or an even number. An expression of the ZC sequence may be in the following form:

[00006] $s_{u} (n) = {\begin{matrix} e^{- j u .Math. n (n + 1) / N_{ZC}}, N_{ZC} is an odd number \\ e^{- j u .Math. n^{2} N_{ZC}}, N_{ZC} is an even number \end{matrix}, n = 0, 1, .Math., N_{ZC} - 1,$ [0120] where N.sub.ZC is the length of the Zadoff-Chu sequence and is an integer greater than 1, a root index (root index) u=1, 2, . . . , N.sub.ZC1, and the root index u and the sequence length N.sub.ZC are mutually prime.

[0121] The Zadoff-Chu sequence has the following properties:

[0122] (1) The sequence is a periodic sequence, and a periodicity of the sequence is equal to the sequence length N.sub.ZC, that is, s.sub.u(nN.sub.ZC)=s.sub.u(n).

[0123] (2) The sequence has a constant amplitude value, and the amplitude value is 1, that is, |s.sub.u(n)|=1.

[0124] (3) A sequence obtained through discrete Fourier transform (DFT) is still a constant-amplitude sequence, and the sequence may be obtained by performing a weighted shift on an original Zadoff-Chu sequence, to omit a DFT operation.

[0125] (4) The ZC sequence has an ideal correlation property. A correlation value between two Zadoff-Chu sequences obtained by performing different cyclic shifts on a Zadoff-Chu sequence with a same root index is 0, or the two Zadoff-Chu sequences are orthogonal to each other. For any Zadoff-Chu sequences with different root indexes (for example, u.sub.1 and u.sub.2), when |u.sub.1u.sub.2| and the sequence length N.sub.ZC are mutually prime, an amplitude of a correlation value between the sequences is a fixed value.

[0126] The Zadoff-Chu sequence is widely used in a communication system because of the foregoing specific properties. Examples are as follows:

[0127] (1) A signal of the Zadoff-Chu sequence has a low peak-to-average power ratio due to the constant amplitude property of the Zadoff-Chu sequence, so that efficiency of a device power amplifier can be improved.

[0128] (2) The ideal correlation property of the Zadoff-Chu sequence is used for synchronization, timing estimation, ranging, and signal sensing.

[0129] (3) The ideal correlation property of the Zadoff-Chu sequence is used as a signature (signature) sequence or a preamble (preamble) for user identification, cell identification, or beam identification.

2. Quadratic Exponential Sequence

[0130] The quadratic exponential sequence is a sequence in which an order of a highest-order item in exponential factors is 2, and may not be subject to the constraint that the root index in the Zadoff-Chu sequence and the sequence length are mutually prime. In the quadratic exponential sequence, a quadratic term coefficient (corresponding to the root index in the Zadoff-Chu sequence) and the sequence length may be or not be mutually prime. Therefore, some quadratic exponential sequences also have the properties of the Zadoff-Chu sequence.

3. Doppler Shift

[0131] When a vibration source like sound, light, or a radio wave moves relative to an observer at a relative velocity, a frequency of vibration received by the observer is different from a frequency provided by the vibration source. This phenomenon is referred to as a Doppler effect. A frequency change caused by the Doppler effect is referred to as a Doppler shift, which is proportional to the relative velocity and proportional to the vibration frequency.

4. Zero Ambiguity Zone/Low Ambiguity Zone

[0132] For a transmission signal whose duration is T and bandwidth is B, an ambiguity function of the transmission signal is usually defined in delay-Doppler domain with a delay range of 0 to T and a Doppler shift range of B/2 to B/2. Therefore, the ambiguity function essentially refers to an output response of a matched transmit signal filter through which a signal (on which a delay and a Doppler shift are performed) received by a receive end passes. If a signal having an extremely low ambiguity function value exists in a zone of the delay-Doppler domain, the zone is referred to as a low ambiguity zone (LAZ). If a signal having a zero ambiguity function value exists in another zone of the delay-Doppler domain, the zone is referred to as a zero ambiguity zone (ZAZ).

5. Maximum Delay .sub.T and Maximum Doppler Shift .sub.F

[0133] Within a zone (for example, a first zone), ranges between different sending devices and a receiving device may be different, and delays of signals arriving at the receiving device are also different. Therefore, a maximum value of round-trip transmission delays that may be corresponding to the sending devices within the first zone needs to be considered for a delay domain cyclic shift. Therefore, the maximum delay .sub.T may be determined based on a radius of the first zone.

[0134] It may be further understood that movement of the sending device relative to the receiving device causes a Doppler shift, and different moving velocities of the sending devices also cause different Doppler shifts. When the moving velocity of the sending device increases, the Doppler shift also increases accordingly. Therefore, a maximum Doppler shift that may be corresponding to the sending devices within the first zone needs to be considered for a Doppler domain cyclic shift. Therefore, the maximum Doppler shift .sub.F is determined based on a possible maximum moving velocity of the sending devices within the first zone.

[0135] The first zone may be a cell, a sensing zone, or the like.

[0136] For example, in a communication system, a zone covered by an access network device or a part of the zone covered by the access network device is referred to as a cell, or is referred to as a cellular cell. Because ranges between different terminals and the access network device are different, delays of signals arriving at the access network device are also different. Therefore, a maximum value of round-trip transmission delays that may be corresponding to the terminals within the cell needs to be considered for a delay domain cyclic shift. Therefore, the maximum delay .sub.T may be determined based on a radius of the cell.

[0137] It may be further understood that movement of the terminal causes a Doppler shift, and different moving velocities of the terminals also cause different Doppler shifts. When a moving velocity of a user increases, the Doppler shift also increases accordingly. Therefore, a maximum Doppler shift that may be corresponding to the terminals within the cell needs to be considered for a Doppler domain cyclic shift. Therefore, the maximum Doppler shift .sub.F is determined based on a possible maximum moving velocity of the terminals within the cell.

[0138] It can be learned from the foregoing analysis that Zadoff-Chu sequences with a same root index but different cyclic shifts are orthogonal to each other to form a zero correlation zone. Different cyclic shifts are performed on a Zadoff-Chu sequence with a same root index to obtain Zadoff-Chu sequences that are orthogonal to each other, which may be used to implement uplink access, delay estimation, and signal sensing, to obtain, through measurement, a range between a terminal device and a base station.

[0139] An expression of a discrete-time signal of the Zadoff-Chu sequence s.sub.u,k(n) using the correlation property may be expressed in the following form:

[00007] $\begin{matrix} s_{u, k} (n) = e^{- j u (n + k_{T}) (n + k_{T} + 1) / N_{ZC}}, n = 0, 1, .Math., N_{ZC} - 1 & (1.1) \end{matrix}$

[0140] In the formula (1.1), the sequence length N.sub.ZC is a prime number, the root index u=1, 2, . . . , N.sub.ZC1, the zero correlation zone represents .sub.T, .sub.T represents a maximum delay, and a cyclic shift index k=0, 1, . . . , N.sub.ZC/.sub.T1. A symbol + represents rounding down.

[0141] A Zadoff-Chu sequence set may be obtained by performing different cyclic shifts on the Zadoff-Chu sequence with a same root index shown in the formula (1.1). The Zadoff-Chu sequence set includes N.sub.ZC/.sub.T Zadoff-Chu sequences: s.sub.u,0(n), s.sub.u,1(n), . . . , and s.sub.u,N.sub.ZC.sub./.sub.T.sub.-1(n). The sequences in the Zadoff-Chu sequence set are orthogonal to each other, and may form a zero correlation zone, to multiplex a given physical random access channel (PRACH) resource.

[0142] However, when a Doppler shift exists, a frequency offset causes a cyclic shift of a signal based on the Zadoff-Chu sequence shown in the formula (1.1), affecting the correlation of the Zadoff-Chu sequence. When the frequency offset is serious, one Zadoff-Chu sequence may overlap with another Zadoff-Chu sequence, increasing a probability of misjudgment and reducing a quantity of available Zadoff-Chu sequences. In addition, a shift of a received signal deviates from a shift of an original sending signal, affecting detection of the receive end and deteriorating performance.

[0143] FIG. 2 is a diagram of simulation an ambiguity function of a Zadoff-Chu sequence using a correlation property according to an embodiment of this disclosure. According to the formula (1.1), a Zadoff-Chu sequence s.sub.4,0(n) whose root index is 4 may be obtained. It can be learned from FIG. 2 that, when a Doppler shift exists, a signal cyclic shift is caused to the Zadoff-Chu sequence s.sub.4,0(n) whose root index is 4. Therefore, an ambiguity function of the Zadoff-Chu sequence s.sub.4,0(n) whose root index is 4 has a plurality of peaks within a range scope of 0 to 240. The peak is a white bright spot shown in FIG. 2. That is, the Zadoff-Chu sequence whose root index is 4 no longer has an ideal correlation property, and a correlation value between Zadoff-Chu sequences with different cyclic shifts may not be 0. When the correlation value is large, a receive end may obtain incorrect delay estimation. Therefore, the Doppler shift affects detection performance of a random access signal or sensing performance of a sensing signal based on a Zadoff-Chu sequence.

[0144] To improve a capability of resisting the Doppler shift, the cyclic shift of the Zadoff-Chu sequence may be restricted, and a cyclic shift is selected from a restricted set to achieve purposes of measuring the delay and resisting Doppler.

[0145] In addition, the Zadoff-Chu sequence may be periodically repeated to obtain an extended Zadoff-Chu sequence, and a zero ambiguity zone is constructed by using a delay domain cyclic shift. An expression of a discrete-time signal of the extended Zadoff-Chu sequence may be as follows:

[00008] $\begin{matrix} s_{N_{F}, k} (n) = e^{- j N_{F} (n + k_{T}) (n + k_{T} + 1) / N}, n = 0, 1, .Math., N - 1 & (2.1) \end{matrix}$

[0146] In the formula (2.1), N represents a length of the extended Zadoff-Chu sequence, a value is a composite number, N.sub.T represents a length of a single Zadoff-Chu sequence, N.sub.F represents a quantity of periodic repetitions of the extended Zadoff-Chu sequence, the quantity N.sub.F of periodic repetitions is exactly divided by the length N=N.sub.FN.sub.T of the extended Zadoff-Chu sequence, .sub.T represents a maximum delay in a delay range, and a cyclic shift index k=0, 1, . . . , N.sub.T/.sub.T1.

[0147] An extended Zadoff-Chu sequence set may be obtained by performing different cyclic shifts on the sequence shown in the formula (2.1). The extended Zadoff-Chu sequence set includes N.sub.T/.sub.T extended Zadoff-Chu sequences: s.sub.N.sub.F.sub.,0(n), s.sub.N.sub.F.sub.,1(n), . . . , and s.sub.N.sub.F.sub.,N.sub.T.sub./.sub.T.sub.-1(n). In addition, a zero ambiguity zone may be formed between the N.sub.T/.sub.T sequences, to multiplex a given PRACH resource.

[0148] When a Doppler shift exists, because a delay domain cyclic shift is used in the formula (2.1), an ambiguity function of the extended Zadoff-Chu sequence shown in the formula (2.1) has only a single peak within a specific delay interval. FIG. 3 is a diagram of simulation of an ambiguity function of an extended Zadoff-Chu sequence using an ambiguity property according to an embodiment of this disclosure. According to the formula (2.1), two extended Zadoff-Chu sequences s.sub.61,0(n) and s.sub.61,2(n) whose quantities of periodic repetitions are 61 may be obtained. It can be learned from FIG. 3 that an ambiguity function of the extended Zadoff-Chu sequence s.sub.61,0(n) whose quantity of periodic repetitions is 61 has one peak within a delay range of 0 to 240, and an ambiguity function of the extended Zadoff-Chu sequence s.sub.61,2(n) also has one peak within a delay range of 240 to 480. Therefore, s.sub.61,0(n) and s.sub.61,2(n) are orthogonal to each other. However, for an extended Zadoff-Chu sequence using a cyclic shift sequence in delay domain, division is performed only in delay domain to construct a zero ambiguity zone, and the zero ambiguity zone cannot be constructed based on a maximum Doppler shift. Consequently, there are few available extended Zadoff-Chu sequences, and a sequence capacity is limited.

[0149] Therefore, to simultaneously observe ranges and velocities by using a plurality of sequences, in this disclosure, a delay domain cyclic shift and a Doppler domain cyclic shift are performed on a quadratic exponential sequence with a same quadratic term coefficient by using a property of a zero ambiguity zone of the quadratic exponential sequence, to construct more zero ambiguity zones, so as to increase the sequence capacity.

[0150] The following describes in detail the method in embodiments of this disclosure.

[0151] FIG. 4 is a schematic flowchart of a communication method according to an embodiment of this disclosure. Optionally, the method may be applied to the foregoing communication system, for example, the communication system described in the implementation in FIG. 1.

[0152] The communication method shown in FIG. 4 may include one or more of step S401 to step S403. It should be understood that, for ease of description in this disclosure, an execution time point, a quantity of execution times, and the like of the foregoing one or more step are not limited in embodiments of this disclosure.

[0153] In the communication method shown in FIG. 4, a first apparatus and a second apparatus may be terminal devices, or communication units, components, or chips in the terminal devices, or apparatuses that are used in cooperation with the terminal devices. Alternatively, the first apparatus and the second apparatus may be network devices, or communication units, components, or chips in the network devices, or apparatuses that are used in cooperation with the network devices.

[0154] Step S401 to step S403 are specifically as follows.

[0155] Step S401: The first apparatus obtains a cyclic shift sequence. The cyclic shift sequence includes a delay domain cyclic shift and a Doppler cyclic shift.

[0156] In a possible implementation, the cyclic shift sequence is a sequence in a quadratic exponential sequence set, and the quadratic exponential sequence set is a sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on a quadratic exponential sequence.

[0157] In another possible implementation, a zero ambiguity zone includes cyclic shift sequences with a same quadratic term coefficient in the quadratic exponential sequence set, and a low ambiguity zone includes cyclic shift sequences with different quadratic term coefficients in the quadratic exponential sequence set. When a quantity of cyclic shift sequences generated by using a same quadratic term coefficient cannot meet a requirement on a total quantity of users needing to be supported, a cyclic shift sequence generated by using a different quadratic term coefficient may be added.

[0158] In a possible implementation, an expression of a discrete-time signal of the cyclic shift sequence based on the quadratic exponential sequence is as follows:

s.sub.u,k,l(n)=e.sup.j[u(n+k.sup.T.sup.)(n+k.sup.T.sup.+1)+2nl.sup.F.sup.]/N,n=0,1, . . . ,N1(3.1)

[0159] In the formula (3.1), s.sub.u,k,l(n) is the quadratic exponential sequence, N represents a sequence length, the sequence length is a composite number, u represents a quadratic term coefficient, the quadratic term coefficient includes a prime factor of the sequence length, k represents an index of the delay cyclic shift, l represents an index of the Doppler cyclic shift, .sub.T represents a preset maximum delay, and .sub.F represents a preset maximum Doppler shift.

[0160] In a possible implementation, the first apparatus obtains sequence configuration information. The sequence configuration information includes one or more of the following parameters: the sequence length N, an available quadratic term coefficient, a delay domain cyclic shift set and a Doppler domain cyclic shift set that are corresponding to each quadratic term coefficient, a maximum delay .sub.T in a first zone, and a maximum Doppler shift .sub.F in the first zone. The first zone may be a cell, a sensing zone, or the like. Then, the first apparatus selects a quadratic term coefficient u, selects a delay cyclic shift index k and a Doppler cyclic shift index l from a delay domain cyclic shift set and a Doppler domain cyclic shift set that are corresponding to the quadratic term coefficient u, and may obtain the cyclic shift sequence s.sub.u,k,l(n) by performing the delay cyclic shift and the Doppler cyclic shift.

[0161] In a possible implementation, the first apparatus receives the sequence configuration information. Optionally, the sequence configuration information may be sent by the second apparatus, or the sequence configuration information is sent by another apparatus.

[0162] In a possible implementation, the sequence configuration information is predefined, for example, predefined in a standard protocol.

[0163] In a possible implementation, the sequence configuration information is determined by the first apparatus. Optionally, the first apparatus further sends the sequence configuration information to the second apparatus.

[0164] The delay cyclic shift index k may also be referred to as a large-scale cyclic shift index. A phase change caused by a cyclic shift of the delay cyclic shift index k is equal to a multiple of the quadratic term coefficient u of the sequence, and does not exceed the sequence length N. Therefore, in a possible design, the delay cyclic shift index k=0, 1, . . . , N/u.sub.T1.

[0165] The Doppler cyclic shift index/may also be referred to as a small-scale cyclic shift index, and means that a phase change caused by a cyclic shift does not exceed the quadratic term coefficient u of the sequence. Therefore, in a possible design, the Doppler cyclic shift index l=0, 1, . . . , u/.sub.F1.

[0166] FIG. 5 is a diagram of an ambiguity function of a cyclic shift sequence according to an embodiment of this disclosure. The ambiguity function shown in FIG. 5 is an ambiguity function of the quadratic exponential sequence set obtained based on the formula (3.1). The quadratic exponential sequence set is obtained by performing k delay domain cyclic shifts and/Doppler domain cyclic shifts that are of a same quadratic term coefficient on the quadratic exponential sequence shown in the formula (3.1).

[0167] It can be learned from FIG. 5 that a horizontal direction represents a velocity, and a vertical direction represents a range. When no cyclic shift is considered, a peak position of the ambiguity function may be determined based on the sequence length N and the quadratic term coefficient u, and a circle represents the peak position of the ambiguity function. Because the sequence length N in the formula (3.1) is a composite number, the sequence length N may be decomposed into a product of a plurality of prime numbers, the quadratic term coefficient u is a prime factor of the sequence length N, and a phase change caused by the delay cyclic shift k is a multiple of the quadratic term coefficient u. Therefore, a peak position of an ambiguity function of each cyclic shift sequence obtained according to the formula (3.1) is periodic, a peak may appear at any range coordinate, and a peak may appear at a specific velocity coordinate.

[0168] To increase a sequence capacity, a delay domain cyclic shift and a Doppler domain cyclic shift are performed. A sequence may be multiplexed by performing the delay domain cyclic shift and the Doppler domain cyclic shift, to obtain more available sequences. A zero ambiguity zone .sub.T.sub.F may be determined based on the maximum delay .sub.T and the maximum Doppler shift .sub.F. When .sub.T=2 and .sub.F=2, a 22 grid shown in FIG. 5 is a zero ambiguity zone. After the delay domain cyclic shift and the Doppler domain cyclic shift that are of the same quadratic term coefficient are performed according to the formula (3.1), the cyclic shift sequence can be multiplexed. It can be learned from FIG. 4 that when the delay domain cyclic shift index is 2 and the Doppler domain cyclic shift index is 3, a total of six cyclic shifts can be multiplexed. An ambiguity function of a cyclic shift sequence obtained by multiplexing a sequence by using a property of the zero ambiguity zone has only one peak within each zero ambiguity zone .sub.T.sub.F (the peak is not completely shown in FIG. 4). A sequence capacity of the zero ambiguity zone is N/u.sub.Tu/.sub.F, and adjacent zero ambiguity zones .sub.T.sub.F do not overlap.

[0169] It can be further learned from FIG. 5 that, compared with an extended Zadoff-Chu sequence on which only a delay domain cyclic shift is performed, a delay domain cyclic shift and a Doppler domain delay shift may be performed on a quadratic exponential sequence to construct more zero ambiguity zones, and an available quantity of the quadratic exponential sequence is increased, to increase the sequence capacity.

[0170] When the sequence length N=7747, the quadratic term coefficient u=61, and a zero ambiguity zone determined based on cell information is: .sub.T.sub.F=4010, the delay domain cyclic shift k=0, 1, . . . , N/u.sub.T1=0, 1, 2 and the Doppler domain cyclic shift l=0, 1, . . . , u/.sub.F1=0, 1, . . . , 5 may be obtained. Therefore, 18 cyclic shift sequences may be obtained by performing, according to the formula (3.1), the delay domain cyclic shift and the Doppler domain cyclic shift on the quadratic exponential sequence whose sequence length N is 7747 and whose quadratic term coefficient u is 61.

[0171] FIG. 6A and FIG. 6B are a diagram of simulation of an ambiguity function of a cyclic shift sequence according to an embodiment of this disclosure. FIG. 6A is a diagram of simulation of ambiguity functions of the foregoing 18 cyclic shift sequences, and FIG. 6B may be obtained by partially zooming-in a zone 501 (for example, a zone determined based on a range scope of 0 meters (m) to 700 m and a velocity range of 600 kilometers per hour (km/h) to 600 km/h) in FIG. 6A. It can be learned from FIG. 6B that the zone 501 includes three cyclic shift sequences s.sub.61,0,0(n), s.sub.61,0,2(n), s.sub.61,2,0(n), a white bright spot shown in the figure is a peak of an ambiguity function, and each dashed-line box represents a zero ambiguity zone. Peaks of ambiguity functions of the three cyclic shift sequences may be within different zero ambiguity zones by performing different delay domain cyclic shifts and different Doppler domain cyclic shifts. This indicates that the three cyclic shift sequences are orthogonal to each other. After receiving the three cyclic shift sequences, the receive end (the second apparatus) can obtain, through measurement, a range and a velocity of a target object without ambiguity.

[0172] In a possible implementation, a value of the sequence length N may be equal to a product of M (N.sub.1, N.sub.2, . . . , N.sub.M) mutually different prime numbers, that is, N=N.sub.1.Math.N.sub.2.Math. . . . .Math.N.sub.M. Therefore, the quadratic exponential sequence includes sequences with the M mutually different prime numbers as quadratic term coefficients. The quadratic exponential sequence set includes G sequence sets obtained by separately performing delay domain cyclic shifts and Doppler domain cyclic shifts on the sequences with the M mutually different prime numbers as quadratic term coefficients, where (is a positive integer. An upper bound of a sequence capacity that can be supported is MN/.sub.T.sub.F.

[0173] In a possible design, when M is equal to 2, the sequence length is equal to a first prime number multiplied by a second prime number. The quadratic exponential sequence includes a first sequence with the first prime number as a quadratic term coefficient and a second sequence with the second prime number as a quadratic term coefficient. The quadratic exponential sequence set includes a first sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the first sequence with the first prime number as a quadratic term coefficient, and a second sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the second sequence with the second prime number as a quadratic term coefficient. Therefore, when a quantity of cyclic shift sequences generated by using the first prime number as the quadratic term coefficient cannot meet the requirement on the total quantity of users needing to be supported, a cyclic shift sequence generated by using the second prime number as the quadratic term coefficient may be added.

[0174] In a possible implementation, when M is equal to 3, the sequence length is equal to a third prime number multiplied by a fourth prime number multiplied by a fifth prime number. The quadratic exponential sequence includes a third sequence with the third prime number as a quadratic term coefficient, a fourth sequence with the fourth prime number as a quadratic term coefficient, and a fifth sequence with the fifth prime number as a quadratic term coefficient. The quadratic exponential sequence set includes a third sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the third sequence with the third prime number as a quadratic term coefficient, a fourth sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the fourth sequence with the fourth prime number as a quadratic term coefficient, and a fifth sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the fifth sequence with the fifth prime number as a quadratic term coefficient. Therefore, when a quantity of cyclic shift sequences generated by using the third prime number as the quadratic term coefficient cannot meet the requirement on the total quantity of users needing to be supported, a cyclic shift sequence generated by using the fourth prime number as the quadratic term coefficient may be added. When a quantity of cyclic shift sequences generated by using the fourth prime number as the quadratic term coefficient cannot meet the requirement on the total quantity of users needing to be supported, a cyclic shift sequence generated by using the fifth prime number as the quadratic term coefficient may be added.

[0175] In a possible implementation, when the cyclic shift sequence is used to generate a random access signal, the first apparatus may obtain, based on random access information broadcast by a network device, related information for sending the random access signal, including the sequence length N, available quadratic term coefficients of the quadratic exponential sequence, and the maximum delay .sub.T and the maximum Doppler shift .sub.F in the cell.

[0176] In a possible implementation, the first apparatus may randomly select a quadratic term coefficient u from the available quadratic term coefficients of the quadratic exponential sequence, and determine, based on the sequence length N, the quadratic term coefficient u, and the maximum delay .sub.T and the maximum Doppler shift .sub.F in the cell, an available delay cyclic shift index k and an available Doppler cyclic shift index l that are corresponding to each quadratic term coefficient. Next, the first apparatus obtains the cyclic shift sequence by performing the delay domain cyclic shift and the Doppler domain cyclic shift on the formula (3.1) based on the sequence length N, the quadratic term coefficient, the maximum delay .sub.T, the maximum Doppler shift .sub.F, the delay cyclic shift index k, and the Doppler cyclic shift index l.

[0177] In a possible implementation, the first apparatus may randomly select a quadratic term coefficient u from the available quadratic term coefficients of the quadratic exponential sequence, then determine a delay cyclic shift index and a Doppler cyclic shift index in a prestored cyclic shift set based on the sequence length N, the quadratic term coefficient u, and the maximum delay .sub.T and the maximum Doppler shift .sub.F in the cell, and perform cyclic shifts on the quadratic exponential sequence based on the delay domain cyclic shift and the Doppler domain cyclic shift.

[0178] In a possible implementation, the first apparatus may randomly select a quadratic term coefficient u from the available quadratic term coefficients of the quadratic exponential sequence, and determine a cyclic shift sequence in a prestored quadratic exponential sequence set based on the sequence length N, the quadratic term coefficient u, and the maximum delay .sub.T and the maximum Doppler shift .sub.F in the cell.

[0179] In another possible implementation, when the cyclic shift sequence is used to generate a sensing signal, the first apparatus may receive configuration information, about the sensing signal, sent by a server or a control node. The configuration information includes related information used to determine the cyclic shift sequence, and may specifically include the sequence length N, the quadratic term coefficient u, one delay cyclic shift in one or more delay cyclic shifts corresponding to the quadratic term coefficient u, one Doppler cyclic shift in one or more Doppler cyclic shifts corresponding to the quadratic term coefficient u, and the maximum delay .sub.T and the maximum Doppler shift .sub.F in the sensing zone. Therefore, the first apparatus may obtain the cyclic shift sequence by performing the delay domain cyclic shift and the Doppler domain cyclic shift on the formula (3.1) based on the sequence length N, the quadratic term coefficient u, the maximum delay .sub.T, the maximum Doppler shift .sub.F, the delay cyclic shift index k, and the Doppler cyclic shift index l.

[0180] In a possible implementation, the first apparatus may determine, based on the sequence length N, the quadratic term coefficient u, and the maximum delay .sub.T and the maximum Doppler shift .sub.F in the cell, a delay cyclic shift index and a Doppler cyclic shift index in a prestored cyclic shift set, and perform cyclic shifts on the quadratic exponential sequence based on the delay domain cyclic shift and the Doppler domain cyclic shift.

[0181] In a possible implementation, the first apparatus may determine the cyclic shift sequence in a prestored quadratic exponential sequence set based on the sequence length N, the quadratic term coefficient u, and the maximum delay .sub.T and the maximum Doppler shift .sub.F in the cell.

[0182] In a possible implementation, when the cyclic shift sequence is used to generate a sensing signal, the first apparatus may determine configuration information of the sensing signal, and obtain the cyclic shift sequence. Optionally, the first apparatus may further send the configuration information of the sensing signal to the second apparatus.

[0183] It may be understood that:

[0184] Step S402: The first apparatus outputs the cyclic shift sequence.

[0185] Specifically, the first apparatus may send the cyclic shift sequence to the second apparatus. Correspondingly, the second apparatus may receive the cyclic shift sequence from the first apparatus, or the second apparatus may receive a cyclic shift sequence reflected by the target object.

[0186] In a possible implementation, the first apparatus performs N-point DFT transform on the cyclic shift sequence to obtain a cyclic shift sequence distributed in frequency domain, or may perform a weighted shift on the cyclic shift sequence to obtain a cyclic shift sequence distributed in frequency domain, to omit a DFT operation. Next, subcarrier mapping is performed, the cyclic shift sequence that is distributed in frequency domain and that is obtained through the DFT is mapped to a corresponding subcarrier position, a time domain signal may be obtained after IDFT is performed on the mapped cyclic shift sequence distributed in frequency domain, and a time domain signal including the cyclic shift sequence is sent to the second apparatus or the target object after corresponding processing (for example, inserting a cyclic prefix) is performed on the time domain signal.

[0187] Step S403: The second apparatus processes the cyclic shift sequence.

[0188] In a possible implementation, if the cyclic shift sequence is used to generate a random access signal, the terminal device or the first apparatus in the terminal device sends a signal including the cyclic shift sequence to the network device or the second apparatus in the network device, and the network device or the second apparatus in the network device processes the cyclic shift sequence.

[0189] In a possible implementation, if the cyclic shift sequence is used to generate a sensing signal, the network device or the first apparatus in the network device sends a signal including the cyclic shift sequence to the target object, and the target object may reflect the signal including the cyclic shift sequence, so that the signal is received by the network device or the second apparatus in the network device, and the network device or the second apparatus in the network device processes the cyclic shift sequence.

[0190] It may be understood that a zone in which a signal attenuates from a maximum value to a first zero point is referred to as a main lobe, and a zone, between adjacent zero points, next to the main lobe is referred to as a side lobe or a sidelobe. For a signal whose time and bandwidth are restricted, a side lobe appears for the ambiguity function of the cyclic shift sequence. In a possible case, a peak of an ambiguity function of the cyclic shift sequence causes a side lobe to appear within a zero ambiguity zone between adjacent Doppler cyclic shifts. The side lobe is not conducive to Doppler estimation, and the cyclic shift sequence needs to be suppressed.

[0191] FIG. 7A is a diagram of side lobes appearing within a zero ambiguity zone according to an embodiment of this disclosure. It can be learned from FIG. 7A that, for a cyclic shift sequence s.sub.61,0,2(n), a peak of an ambiguity function of s.sub.61,0,2(n) is within a first zero ambiguity zone, and a side lobe of an ambiguity function of s.sub.61,0,0(n) also appears within the first zero ambiguity zone. For a cyclic shift sequence s.sub.61,0,0(n), a peak of the ambiguity function of s.sub.61,0,0(n) is within a second zero ambiguity zone, and a side lobe of the ambiguity function of s.sub.61,0,2(n) also appears within the second zero ambiguity zone. Therefore, a side lobe appearing within a zero ambiguity zone in which the peak of the ambiguity function is located causes interference to signal processing. This is unfavorable to Doppler estimation.

[0192] In a possible implementation, before calculating the ambiguity function of the cyclic shift sequence, the second apparatus first performs time domain windowing processing on the received cyclic shift sequence. Windowing means that a window function is used as a modulation wave, and an input signal is used as a carrier for amplitude modulation. FIG. 7B is a diagram of a receive window function according to an embodiment of this disclosure. By using a raised cosine window, a main lobe is widened and its amplitude is reduced, and side lobes of an ambiguity function are suppressed, so that the side lobes counteract each other.

[0193] FIG. 7C to FIG. 7E are a diagram of suppressing a Doppler side lobe by using different roll-off factors according to an embodiment of this disclosure. A roll-off factor in FIG. 7C is 0, a roll-off factor in FIG. 7D is a reciprocal of the quadratic term coefficient of the sequence, and a roll-off factor in FIG. 7E is 1. Through comparison of FIG. 7C to FIG. 7E, the roll-off factors are sequentially increased, and simulation results show that attenuation speeds of the side lobe are also sequentially increased. It indicates that the raised cosine window function may suppress the side lobe of the ambiguity function, reducing interference.

[0194] FIG. 7F and FIG. 7G are a diagram of comparison between ambiguity functions of two sequences according to an embodiment of this disclosure. FIG. 7F is an ambiguity function of a Prouhet-Thue-Morse sequence, and FIG. 7G is an ambiguity function of a quadratic exponential sequence. It can be learned that in an actual Doppler model, a side lobe suppression capability of the quadratic exponential sequence is stronger than that of the Prouhet-Thue-Morse sequence. In addition, a sequence capacity obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the quadratic exponential sequence can be larger than that of a Gray complementary sequence pair. Therefore, in a communication system, generating a random access signal or a sensing signal by using a quadratic exponential sequence can improve system performance and save resources.

[0195] Scenarios to which embodiments of this disclosure are applicable include but are not limited to the following scenarios.

[0196] [Scenario 1] A quadratic exponential sequence is used to generate a random access signal.

[0197] In a possible implementation scenario, the terminal device 104 shown in FIG. 1 is used as an example for description. The terminal device 104 obtains a cyclic shift sequence. The cyclic shift sequence includes a delay domain cyclic shift and a Doppler domain cyclic shift. The cyclic shift sequence is a sequence in a quadratic exponential sequence set, and the quadratic exponential sequence set is a sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the quadratic exponential sequence. A zero ambiguity zone includes sequences with a same quadratic term coefficient in the quadratic exponential sequence set, and a low ambiguity zone includes sequences with different quadratic term coefficients in the quadratic exponential sequence set. Specifically, the terminal device 104 may obtain the cyclic shift sequence based on the foregoing communication method, for example, the communication method shown in FIG. 4.

[0198] The terminal device 104 sends a random access signal including the cyclic shift sequence to the network device 111 or a functional module in the network device.

[0199] The network device 111 or the functional module in the network device may receive the random access signal including the cyclic shift sequence, and implement downlink signal synchronization and uplink random access of the terminal device 104 based on a correlation of the cyclic shift sequence. Specifically, the network device 111 may obtain, through measurement based on the cyclic shift sequence, a range between the terminal device 104 and the network device 111 or a velocity of the terminal device 104 relative to the network device 111. The network device 111 may calculate, based on the range or the velocity, a timing advance needed by the terminal device 104, and feed back the timing advance to the terminal device 104. Therefore, in a random access process, the terminal device 104 is identified by the network device 111, and obtains the timing advance estimated by the network device 111, to establish uplink and downlink synchronization and construct a bidirectional link between the terminal device 104 and the network device 111. Then, the terminal device 104 may perform data transmission based on a resource scheduled by the network device 111.

[0200] [Scenario 2] A quadratic exponential sequence is used to generate a sensing signal.

[0201] In a possible implementation scenario, the network device 111 shown in FIG. 1 is used as an example for description. The network device 111 obtains a cyclic shift sequence. The cyclic shift sequence includes a delay domain cyclic shift and a Doppler domain cyclic shift. The cyclic shift sequence is a sequence in a quadratic exponential sequence set, and the quadratic exponential sequence set is a sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the quadratic exponential sequence. A zero ambiguity zone includes sequences with a same quadratic term coefficient in the quadratic exponential sequence set, and a low ambiguity zone includes sequences with different quadratic term coefficients in the quadratic exponential sequence set. Specifically, the network device 111 may obtain the cyclic shift sequence based on the foregoing communication method, for example, the communication method shown in FIG. 4.

[0202] In a possible implementation, the network device 111 may receive sequence configuration information sent by a server or a control node (not shown in FIG. 1), or may receive sequence configuration information sent by the terminal device, or may receive sequence configuration information sent by the network device 112.

[0203] The network device 111 sends a sensing signal including the cyclic shift sequence to a target object (for example, a vehicle in an ambient environment).

[0204] The target object may reflect the sensing signal including the cyclic shift sequence, so that the sensing signal is received by the network device 111 or a functional module in the network device 111. The network device 111 or the functional module in the network device 111 determines some attributes of the target object based on the reflection of the sensing signal, including one or more of a range, a position, a shape, or a velocity.

[0205] In a possible implementation, the sensing signal including the cyclic shift sequence that is reflected by the target object may be received by the network device 112 or a functional module in the network device 112. The network device 112 or the functional module in the network device 112 determines some attributes of the target object based on the reflection of the sensing signal, including one or more of a range, a position, a shape, or a velocity.

[0206] In another possible implementation, the sensing signal including the cyclic shift sequence that is reflected by the target object may be received by the terminal device or a functional module in the terminal device. The terminal device or the functional module in the terminal device determines some attributes of the target object based on the reflection of the sensing signal, including one or more of a range, a position, a shape, or a velocity.

[0207] It should be noted that the terminal device or the functional module in the terminal device may alternatively obtain the cyclic shift sequence, to send the sensing signal including the cyclic shift sequence to the target object.

[0208] The following describes some possible implementations of the cyclic shift sequence.

Implementation 1

[0209] In a possible implementation, a value of the sequence length N may be equal to a product of M (N.sub.1, N.sub.2, . . . , N.sub.M) mutually different prime numbers, that is, N=N.sub.1.Math.N.sub.2.Math. . . . .Math.N.sub.M. Therefore, the quadratic exponential sequence includes sequences with the M mutually different prime numbers as quadratic term coefficients. The quadratic exponential sequence set includes G sequence sets obtained by separately performing delay domain cyclic shifts and Doppler domain cyclic shifts on the sequences with the M mutually different prime numbers as quadratic term coefficients, where G is a positive integer. An upper bound of a sequence capacity that can be supported is MN/.sub.T.sub.F.

[0210] When M=2, the sequence length N is equal to a first prime number P multiplied by a second prime number Q, that is, N=P.Math.Q. The quadratic exponential sequence may include a first sequence with the first prime number P as a quadratic term coefficient and a second sequence with the second prime number (as a quadratic term coefficient.

[0211] An expression of a discrete-time signal of the first sequence with the first prime number P as a quadratic term coefficient may be as follows:

[00009] $\begin{matrix} s_{P, k, l} (n) = e^{- j [P (n + k_{T}) (n + k_{T} + 1) + 2 n l_{F}] / N}, n = 0, 1, .Math., N - 1, & (4.1) \end{matrix}$

where a delay cyclic shift index k=0, 1, . . . , Q/.sub.T1, a Doppler cyclic shift index l=0, 1, . . . , P/.sub.F1, and a sequence capacity of a zero ambiguity zone is Q/.sub.TP/.sub.F. A first sequence set is obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the first sequence s.sub.P,k,l(n) with the first prime number P as a quadratic term coefficient. The zero ambiguity zone includes cyclic shift sequences in the first sequence set.

[0212] An expression of a discrete-time signal of the second sequence with the second prime number Q as a quadratic term coefficient may be as follows:

[00010] $\begin{matrix} s_{Q, k, l} (n) = e^{- j [Q (n + k_{T}) (n + k_{T} + 1) + 2 n l_{F}] / N}, n = 0, 1, .Math., N - 1, & (4.2) \end{matrix}$

where a delay cyclic shift index k=0, 1, . . . , P/.sub.T1, a Doppler cyclic shift index l=0, 1, . . . , Q/.sub.F1, and a sequence capacity of a zero ambiguity zone is P/.sub.TQ/.sub.F. A second sequence set is obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the second sequence s.sub.Q,k,l(n) with the second prime number (as a quadratic term coefficient. The zero ambiguity zone includes cyclic shift sequences in the second sequence set.

[0213] A low ambiguity zone includes the first sequence s.sub.P,k,l(n) with the first prime number P as a quadratic term coefficient and the second sequence s.sub.Q,k,l(n) with the second prime number Q as a quadratic term coefficient. An ambiguity function between the first sequence and the second sequence may be expressed as follows:

[00011] $\begin{matrix} A_{s_{P, k, l^{, s} Q,,}} (, v) = {.Math.}_{n = 0}^{N - 1} s_{P, k, l} (n) s_{Q,,}^{*} (n +) e^{j 2 n v / N}, n = 0, 1, .Math., N - 1, & (4.3) \end{matrix}$

where represents a time difference between delays of echo signals of an apparatus for transmitting the first sequence and an apparatus for transmitting the second sequence relative to the transmit signal, and represents a Doppler frequency difference between the apparatus for transmitting the first sequence and the apparatus for transmitting the second sequence.

[0214] A maximum value

[00012] $\max_{, v} .Math. A_{s_{P, k, l^{, s} Q,,}} (, v) .Math. = \sqrt{N \gcd (Q - P, N)} = \sqrt{N}$

of the ambiguity function between the first sequence s.sub.P,k,l(n) and the second sequence s.sub.Q,k,l(n) may be obtained through calculation, where gcd represents a greatest common divisor (GCD), and a greatest common divisor of two numbers a and b is a greatest positive integer that exactly divides both a and b, which is denoted as gcd(a, b).

[0215] It can be learned that, because the sequence length being a composite number is decomposed into a product of two different prime numbers N=P.Math.Q, in a maximum value {square root over (N gcd(QP,N))}, QP and N are always mutually prime. It should be noted that, when the two prime numbers are different, a greatest common factor of the two prime numbers is 1. Therefore, a maximum value {square root over (N)} of the ambiguity function in the low ambiguity zone is the same as that of an existing ZC sequence.

[0216] FIG. 8A and FIG. 8B are a diagram of an ambiguity function of a cyclic shift sequence whose sequence length is a product of two prime numbers according to an embodiment of this disclosure. When the sequence length N=7747, N=7747=61.127, a first prime number P may be 61, and a second prime number Q may be 127. When a zero ambiguity zone determined based on cell information is: .sub.T.sub.F=401, a delay domain cyclic shift index k=0, 1, . . . , Q/.sub.T1=0, 1, . . . , 127/401=0, 1, 2 of a first sequence and a Doppler domain cyclic shift index l=0, 1, . . . , P/.sub.F1=0, 1, . . . , 61/101=0, 1, 2, 3, 4, 5 of the first sequence may be obtained. Therefore, after delay domain cyclic shifts and Doppler domain cyclic shifts are performed, according to the formula (4.1), on a quadratic exponential sequence whose sequence length N is 7747 and whose quadratic term coefficient P is 61, it can be learned from FIG. 8A that 18 cyclic shift sequences may be obtained: s.sub.61,0,0, s.sub.61,0,1, s.sub.61,0,2, s.sub.61,0,3, s.sub.61,0,4, s.sub.61,0,5, s.sub.61,1,0, s.sub.61,1,1, s.sub.61,1,2, s.sub.61,1,3, s.sub.61,1,4, s.sub.61,1,5, s.sub.61,2,0, s.sub.61,2,1, s.sub.61,2,2, s.sub.61,2,3, s.sub.61,2,4, and s.sub.61,2,5. A peak of an ambiguity function of each cyclic shift sequence is within a different zero ambiguity zone (not shown in the figure).

[0217] A delay domain cyclic shift index of a second sequence is k=0, 1, . . . , P/.sub.T1, where 61/401=0, that is, k=0. A Doppler domain cyclic shift index of the second sequence is l=0, 1, . . . , Q/.sub.F1, where 127/101=11, that is, l=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Therefore, after delay domain cyclic shifts and Doppler domain cyclic shifts are performed, according to the formula (4.1), on a quadratic exponential sequence whose sequence length N is 7747 and whose quadratic term coefficient Q is 127, it can be learned from FIG. 8B that 12 cyclic shift sequences may be obtained: s.sub.127,0,0, s.sub.127,0,1, s.sub.127,0,2, s.sub.127,0,3, s.sub.127,0,4, s.sub.127,0,5, s.sub.127,0,6, s.sub.127,0,7, s.sub.127,0,8, s.sub.127,0,9, s.sub.127,0,10, and s.sub.127,0,11.

[0218] Therefore, when the sequence length N=7747, the first prime number is 61, the second prime number Q is 127, and the zero ambiguity zone in a cell is: .sub.T.sub.F=4010, a total sequence capacity is 30.

[0219] When the sequence length is a product of two different prime numbers, a low ambiguity zone includes cyclic shift sequences with the two different prime numbers as quadratic term coefficients, and a maximum value of an ambiguity function of the low ambiguity zone may be {square root over (N)}. This indicates that there is a low correlation between the two cyclic shift sequences.

Implementation 2

[0220] In a possible implementation, a value of the sequence length N may be equal to a product of M (N.sub.1, N.sub.2, . . . , N.sub.M) mutually different prime numbers, that is, N=N.sub.1.Math.N.sub.2.Math. . . . .Math.N.sub.M. Therefore, the quadratic exponential sequence includes sequences with the M mutually different prime numbers as quadratic term coefficients. The quadratic exponential sequence set includes G sequence sets obtained by separately performing delay domain cyclic shifts and Doppler domain cyclic shifts on the sequences with the M mutually different prime numbers as quadratic term coefficients, where G is a positive integer. An upper bound of a sequence capacity that reaches a maximum value {square root over (N)} of the ambiguity function is MN/.sub.T.sub.F.

[0221] When M=3, the sequence length N is equal to a third prime number P multiplied by a fourth prime number (multiplied by a fifth prime number R, that is, N=P.Math.Q.Math.R. Therefore, the quadratic exponential sequence may include a third sequence with the third prime number P as a quadratic term coefficient, a fourth sequence with the fourth prime number Q as a quadratic term coefficient, and a fifth sequence with the fifth prime number R as a quadratic term coefficient.

[0222] An expression of a discrete-time signal of the third sequence with the third prime number P as a quadratic term coefficient may be as follows:

[00013] $\begin{matrix} s_{P, k, l} (n) = e^{- j [P (n + k_{T}) (n + k_{T} + 1) + 2 n l_{F}] / N}, n = 0, 1, .Math., N - 1, & (5.1) \end{matrix}$

where a delay cyclic shift index k=0, 1, . . . , QR1, a Doppler cyclic shift index l=0, 1, . . . , P/.sub.F1, and a sequence capacity of a zero ambiguity zone is QR/.sub.TP/.sub.F. A third sequence set is obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the third sequence s.sub.P,k,l(n) with the third prime number P as a quadratic term coefficient. The zero ambiguity zone includes cyclic shift sequences in the third sequence set.

[0223] An expression of a discrete-time signal of the fourth sequence with the fourth prime number Q as a quadratic term coefficient may be as follows:

[00014] $\begin{matrix} s_{Q, k, l} (n) = e^{- j [Q (n + k_{T}) (n + k_{T} + 1) + 2 n l_{F}] / N}, n = 0, 1, .Math., N - 1, & (5.2) \end{matrix}$

where a delay cyclic shift index k=0, 1, . . . , RP/.sub.T1, a Doppler cyclic shift index l=0, 1, . . . , Q/.sub.F1, and a sequence capacity of a zero ambiguity zone is RP/.sub.TQ/.sub.F. A fourth sequence set is obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the fourth sequence s.sub.Q,k,l(n) with the fourth prime number Q as a quadratic term coefficient. The zero ambiguity zone includes cyclic shift sequences in the fourth sequence set.

[0224] An expression of a discrete-time signal of the fifth sequence with the fifth prime number R as a quadratic term coefficient may be as follows:

[00015] $\begin{matrix} s_{R, k, l} (n) = e^{- j [R (n + k_{T}) (n + k_{T} + 1) + 2 n l_{F}] / N}, n = 0, 1, .Math., N - 1, & (5.3) \end{matrix}$

where a delay cyclic shift index k=0, 1, . . . , PQ/.sub.T1, a Doppler cyclic shift index l=0, 1, . . . , R/.sub.F1, and a sequence capacity of a zero ambiguity zone is PQ/.sub.TR/.sub.F. A fifth sequence set is obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the fifth sequence s.sub.R,k,l(n) with the fifth prime number R as a quadratic term coefficient. The zero ambiguity zone includes cyclic shift sequences in the fifth sequence set.

[0225] A low ambiguity zone includes any two of the third sequence s.sub.P,k,l(n) with the third prime number P as a quadratic term coefficient, the fourth sequence s.sub.Q,k,l(n) with the fourth prime number (as a quadratic term coefficient, and the fifth sequence s.sub.R,k,l(n) with the fifth prime number R as a quadratic term coefficient. An ambiguity function between any two of the sequences may be expressed as follows:

[00016] $\begin{matrix} A_{s_{u, k, l^{s} v,,}} (, v) = {.Math.}_{n = 0}^{N - 1} s_{u, k, l} (n) s_{v,,}^{*} (n +) e^{j 2 n v / N}, (u, v) {(P, Q), (Q, R), (P, R)}, & (5. 4) \end{matrix}$

where represents a time difference between delays, relative to a transmit signal, of echo signals of any two apparatuses in an apparatus for transmitting the third sequence, an apparatus for transmitting the fourth sequence, and an apparatus for transmitting the fifth sequence, and represents a Doppler frequency difference between any two apparatuses in the apparatus for transmitting the third sequence, the apparatus for transmitting the fourth sequence, and the apparatus for transmitting the fifth sequence.

[0226] A maximum value of an ambiguity function between any two of the third sequence s.sub.P,k,l(n), the fourth sequence s.sub.Q,k,l(n), and the fifth sequence s.sub.R,k,l(n) is

[00017] $\max_{, v} .Math. A_{s_{u, k, t^{s} v,,}} (, v) .Math. = \sqrt{N \gcd (v - u, N)} = \sqrt{N} .$

[0227] It can be learned that, because the sequence length being a composite number is decomposed into a product of three different prime numbers N=P.Math.Q.Math.R, in a maximum value {square root over (N gcd(vu, N))}, (QP) or (RQ) or (RP) and N are always mutually prime. It should be noted that, when two prime numbers are different, a greatest common factor of the two prime numbers is 1. Therefore, a maximum value {square root over (N)} of the ambiguity function in the low ambiguity zone is the same as that of an existing ZC sequence.

[0228] FIG. 9A to FIG. 9C are a diagram of an ambiguity function of a cyclic shift sequence whose sequence length is a product of three prime numbers according to an embodiment of this disclosure. When the sequence length N=7429, N=7429=17.Math.19.Math.23, a third prime number P may be 17, a fourth prime number Q may be 19, and a fifth prime number R may be 23. When a zero ambiguity zone determined based on cell information is: .sub.T.sub.F=4010, a delay domain cyclic shift k=0, 1, . . . , QR/.sub.T1=0, 1, . . . , 19.Math.23/401=0, 1, 2, 3, 4, 5, 6, 7, 8, 9 of a third sequence and a Doppler domain cyclic shift index l=0, 1, . . . , P/.sub.F1=0, 1, . . . , 17/101=0 of the third sequence may be obtained. Therefore, after delay domain cyclic shifts and Doppler domain cyclic shifts are performed, according to the formula (5.1), on a quadratic exponential sequence whose sequence length N is 7429 and whose quadratic term coefficient P is 17, it can be learned from FIG. 9A that 10 cyclic shift sequences may be obtained: s.sub.17,0,0, s.sub.17,1,0, s.sub.17,2,0, s.sub.17,3,0, s.sub.17,4,0, s.sub.17,5,0, s.sub.17,6,0, s.sub.17,7,0, s.sub.17,8,0, and s.sub.17,9,0. A peak of an ambiguity function of each cyclic shift sequence is within a different zero ambiguity zone (not shown in the figure). In addition, adjacent zero ambiguity zones complementarily overlap.

[0229] A delay domain cyclic shift of a fourth sequence is: k=0, 1, . . . , RP/.sub.T1, where 23.Math.17/401=8, that is, k=0, 1, 2, 3, 4, 5, 6, 7, 8. A Doppler domain cyclic shift of the first sequence is: l=0, 1, . . . , Q/.sub.F, where 18/101=0, that is, l=0. Therefore, after delay domain cyclic shifts and Doppler domain cyclic shifts are performed, according to the formula (5.2), on a quadratic exponential sequence whose sequence length N is 7429 and whose quadratic term coefficient Q is 19, it can be learned from FIG. 9B that nine cyclic shift sequences may be obtained: s.sub.19,0,0, s.sub.19,1,0, s.sub.19,2,0, s.sub.19,3,0, s.sub.19,4,0, s.sub.19,5,0, s.sub.19,6,0, s.sub.19,7,0, and s.sub.19,8,0.

[0230] A delay domain cyclic shift of a fifth sequence is: k=0, 1, . . . , PQ/.sub.T1=0, 1, . . . , 1719/401=0, 1, 2, 3, 4, 5, 6, 7. A Doppler domain cyclic shift of the first sequence is: l=0, 1, . . . , R/.sub.F1=0, 1, . . . , 23/101=0, 1. Therefore, after delay domain cyclic shifts and Doppler domain cyclic shifts are performed, according to the formula (5.3), on a quadratic exponential sequence whose sequence length N is 7429 and whose quadratic term coefficient R is 23, it can be learned from FIG. 9C that 16 cyclic shift sequences may be obtained: s.sub.23,0,0, s.sub.23,1,0, s.sub.23,2,0, s.sub.23,3,0, s.sub.23,4,0, s.sub.23,5,0, s.sub.23,6,0, s.sub.23,7,0, s.sub.23,0,1, s.sub.23,1,1, s.sub.23,2,1, s.sub.23,3,1, s.sub.23,4,1, s.sub.23,5,1, s.sub.23,6,1, and s.sub.23.7.1. A peak of an ambiguity function of each cyclic shift sequence is within a different zero ambiguity zone (not shown in the figure). In addition, adjacent zero ambiguity zones complementarily overlap.

[0231] Therefore, when the sequence length N=7429, the third prime number is 17, the fourth prime number Q is 19, the fifth prime number R is 23, and the zero ambiguity zone in a cell is: .sub.T.sub.F=4010, a total sequence capacity is 35.

[0232] When the sequence length is a product of three different prime numbers, a low ambiguity zone includes cyclic shift sequences with any two of the three different prime numbers as quadratic term coefficients, and a maximum value of an ambiguity function of the low ambiguity zone may be {square root over (N)}. This indicates that there is a low correlation between the two cyclic shift sequences, and a sequence capacity of the low ambiguity zone can be increased.

[0233] The foregoing describes in detail the method in embodiments of this disclosure. The following provides apparatuses in embodiments of this disclosure.

[0234] An embodiment of this disclosure provides a communication apparatus. The communication apparatus may include modules or units that are in one-to-one correspondence with the methods/operations/steps/actions described in the foregoing method embodiments. The module or unit may be a hardware circuit, software, or a combination of the hardware circuit and the software. For example, FIG. 10 is a diagram of a structure of a communication apparatus 100 according to an embodiment of this disclosure. The communication apparatus 100 may include a processing unit 1001 and a communication unit 1002. The communication apparatus 100 is configured to implement the foregoing communication method, for example, the communication method in the embodiment shown in FIG. 4.

[0235] Optionally, the communication apparatus 100 may be the first apparatus, the second apparatus, or the like in the foregoing embodiments, for example, the first apparatus or the second apparatus in the embodiment shown in FIG. 5.

[0236] In a possible implementation, when the communication apparatus 100 is the first apparatus in the foregoing embodiments, the processing unit 1001 is configured to obtain a cyclic shift sequence, where the cyclic shift sequence includes a delay domain cyclic shift and a Doppler domain cyclic shift; and the communication unit 1002 is configured to output the cyclic shift sequence.

[0237] In a possible implementation, the processing unit 1001 is specifically configured to determine the cyclic shift sequence based on a sequence length, a quadratic term coefficient, a preset maximum delay, and a preset maximum Doppler shift.

[0238] In a possible implementation, when the communication apparatus 100 is the second apparatus in the foregoing embodiments, the communication unit 1002 is configured to receive a cyclic shift sequence, where the cyclic shift sequence includes a delay domain cyclic shift and a Doppler cyclic shift; and the processing unit is configured to process the cyclic shift sequence.

[0239] In a possible implementation, the cyclic shift sequence is a sequence in a quadratic exponential sequence set, and the quadratic exponential sequence set is a sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on a quadratic exponential sequence.

[0240] In a possible implementation, a zero ambiguity zone includes cyclic shift sequences with a same quadratic term coefficient in the quadratic exponential sequence set, and a low ambiguity zone includes cyclic shift sequences with different quadratic term coefficients in the quadratic exponential sequence set.

[0241] In a possible implementation, an expression of a discrete-time signal of the quadratic exponential sequence is:

[00018] $s_{u, k, l} (n) = e^{- j [u (n + k_{T}) (n + k_{T} + 1) + 2 n l_{F}] / N}, n = 0, 1, .Math., N - 1,$

where s.sub.u,k,l(n) is the quadratic exponential sequence, N represents a sequence length, the sequence length is a composite number, u represents a quadratic term coefficient, the quadratic term coefficient includes a prime factor of the sequence length, k represents an index of the delay cyclic shift, l represents an index of the Doppler cyclic shift, .sub.T represents a preset maximum delay, and .sub.F represents a preset maximum Doppler shift.

[0242] In a possible implementation, a value of the sequence length is equal to a product of M mutually different prime numbers, where M is a positive integer.

[0243] The quadratic exponential sequence includes sequences with the M mutually different prime numbers as quadratic term coefficients.

[0244] The quadratic exponential sequence set includes (sequence sets obtained by separately performing delay domain cyclic shifts and Doppler domain cyclic shifts on the sequences with the M mutually different prime numbers as quadratic term coefficients, where G is a positive integer.

[0245] In a possible implementation, when M is equal to 2, the sequence length is equal to a first prime number multiplied by a second prime number.

[0246] The quadratic exponential sequence includes a first sequence with the first prime number as a quadratic term coefficient and a second sequence with the second prime number as a quadratic term coefficient.

[0247] The quadratic exponential sequence set includes a first sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the first sequence with the first prime number as a quadratic term coefficient, and a second sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the second sequence with the second prime number as a quadratic term coefficient.

[0248] In a possible implementation, when M is equal to 3, the sequence length is equal to a third prime number multiplied by a fourth prime number multiplied by a fifth prime number.

[0249] The quadratic exponential sequence includes a third sequence with the third prime number as a quadratic term coefficient, a fourth sequence with the fourth prime number as a quadratic term coefficient, and a fifth sequence with the fifth prime number as a quadratic term coefficient.

[0250] The quadratic exponential sequence set includes a third sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the third sequence with the third prime number as a quadratic term coefficient, a fourth sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the fourth sequence with the fourth prime number as a quadratic term coefficient, and a fifth sequence set obtained by performing a delay domain cyclic shift and a Doppler domain cyclic shift on the fifth sequence with the fifth prime number as a quadratic term coefficient.

[0251] In a possible implementation, the cyclic shift sequence is used to generate a random access signal or a sensing signal.

[0252] FIG. 11 is a diagram of a structure of a communication apparatus 110 according to an embodiment of this disclosure. The communication apparatus 110 may be configured to implement functions of the first apparatus and the second apparatus in the foregoing methods. The communication apparatus 110 is an apparatus that has a computing capability and a communication capability. The communication apparatus herein may be a physical device, for example, a network device or a terminal device, or may be a communication unit, a component, or a chip in the network device, or may be a communication unit, a component, or a chip in the terminal device, or may be an apparatus that is used in cooperation with the network device, or may be an apparatus that is used in cooperation with the terminal device.

[0253] As shown in FIG. 11, the communication apparatus 110 includes a processor 1101. In a possible implementation, the communication apparatus 110 may further include at least one communication interface 1102, or the processor 1101 is coupled to the communication interface 1102. In another possible implementation, the communication apparatus 110 may further include at least one memory 1103. The memory 1103 may be integrated with the processor 1101, disposed separately, or located outside the communication apparatus 110. It should be understood that quantities of processors and memories in the communication apparatus 110 are not limited in this disclosure.

[0254] The processor 1101 is a module for performing an operation, and may include any one or more of processors such as a controller (for example, a storage controller), a logic circuit, a baseband processor, a central processing unit (CPU), a micro graphics processing unit (GPU), a microprocessor (MP), a digital signal processor (DSP), a coprocessor (assisting the central processing unit in completing corresponding processing and application), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), and a microcontrol unit (MCU).

[0255] The communication interface 1102 is configured to provide an information input or output for the at least one processor, and/or the communication interface 1102 may be configured to receive data sent from the outside and/or send data to the outside. The communication interface 1102 may be an input/output interface, may be a wired link interface including, for example, an Ethernet cable, or may be a wireless link (Wi-Fi, Bluetooth, universal wireless transmission, and another wireless communication technology) interface. Optionally, the communication interface 1102 may further include a transmitter (for example, a radio frequency transmitter or an antenna), a receiver, or the like that is coupled to the interface. For example, when the communication apparatus 110 is the first apparatus, the communication interface 1102 is configured to send a cyclic shift sequence. When the communication apparatus 110 is the second apparatus, the communication interface 1102 is configured to receive a cyclic shift sequence.

[0256] The memory 1103 is configured to provide storage space. The storage space may optionally store application data, user data, an operating system, a computer program, a configuration file, and the like. The memory 1103 may include a volatile memory, for example, a random-access memory (RAM). The memory 1103 may further include a non-volatile memory, for example, a read-only memory (ROM), a flash memory, a hard disk drive (HDD), or a solid-state drive (SSD).

[0257] The communication apparatus 110 may further include a bus 1104. The bus 1104 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus may be classified into an address bus, a data bus, a control bus, or the like. For ease of representation, the bus is represented by using only one line in FIG. 11. However, this does not indicate that there is only one bus or only one type of bus. The bus 1104 may include a path for transmission of information between various parts (for example, the memory 1103, the processor 1101, and the communication interface 1102) of the communication apparatus 110.

[0258] In this embodiment of this disclosure, the memory 1103 stores executable instructions. The processor 1101 executes the executable instructions to implement the foregoing communication method, for example, the communication method in the embodiment in FIG. 4. In other words, the memory 1103 stores instructions used to perform the communication method.

[0259] In a possible implementation, when the communication apparatus 110 is the first apparatus, the communication apparatus 110 is configured to perform steps performed by the first apparatus in the possible implementations of the foregoing method embodiments. For example, the processor 1101 is configured to obtain the cyclic shift sequence. The cyclic shift sequence includes a delay domain cyclic shift and a Doppler domain cyclic shift. The processor 1101 is configured to send the cyclic shift sequence through the communication interface 1102.

[0260] The processor 1101 is specifically configured to determine the cyclic shift sequence based on a sequence length, a quadratic term coefficient, a preset maximum delay, and a preset maximum Doppler shift.

[0261] In another possible implementation, when the communication apparatus 110 is the second apparatus, the communication apparatus 110 is configured to perform steps performed by the first apparatus in the possible implementations of the foregoing method embodiments. For example, the processor 1101 is configured to receive the cyclic shift sequence through the communication interface 1102. The cyclic shift sequence includes a delay domain cyclic shift and a Doppler domain cyclic shift. The processor 1101 is configured to process the cyclic shift sequence.

[0262] When the communication apparatus 110 is a chip used in the terminal, the chip in the terminal implements a function of the terminal in the foregoing method embodiments. The chip in the terminal receives information from another module (for example, a radio frequency module or an antenna) in the terminal, where the information is sent by another terminal or a network device to the terminal. Alternatively, the chip in the terminal outputs information to another module (for example, a radio frequency module or an antenna) in the terminal, where the information is sent by the terminal to another terminal or a network device.

[0263] When the communication apparatus 110 is a chip used in the network device, the chip in the network device implements a function of the network device in the foregoing method embodiments. The chip in the network device receives information from another module (for example, a radio frequency module or an antenna) in the network device, where the information is sent by a terminal or another network device to the network device. Alternatively, the chip in the network device outputs information to another module (for example, a radio frequency module or an antenna) in the network device, where the information is sent by the network device to a terminal or another network device.

[0264] An embodiment of this disclosure may further provide a computer program product. The computer program product includes computer instructions. When the instructions are run on at least one processor, the foregoing communication method, for example, the communication method in the embodiment in FIG. 4, is implemented.

[0265] In a possible implementation, the computer program product may be a software installation package or an image package. When the foregoing method needs to be used, the computer program product may be downloaded, and the computer program product is executed on a computing device.

[0266] An embodiment of this disclosure may further provide a communication system. The communication system includes a terminal device and a network device. For specific descriptions, refer to the communication method shown in FIG. 4.

[0267] An embodiment of this disclosure may further provide a computer program. The computer program is used to implement the foregoing communication method, for example, the communication method in the embodiment in FIG. 4.

[0268] An embodiment of this disclosure further provides a computer-readable storage medium. The computer-readable storage medium includes instructions. The instructions are used to implement the foregoing communication method, for example, the communication method in the embodiment in FIG. 4.

[0269] The computer-readable storage medium may be any usable medium that can be stored by a communication apparatus, or a data storage device like a data center including one or more usable media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, a digital video disc (DVD)), a semiconductor medium (for example, an SSD), or the like.

[0270] In embodiments of this disclosure, the word like example or for example is used to give an example, an illustration, or a description. Any embodiment or design scheme described as an example or for example in this disclosure should not be explained as being more preferred or having more advantages than another embodiment or design scheme. To be precise, use of the word like example or for example is intended to present a relative concept in a specific manner.

[0271] In embodiments of this disclosure, at least one means one or more, and a plurality of means two or more. At least one of the following items (pieces) or a similar expression thereof means any combination of these items, including a single item (piece) or any combination of a plurality of items (pieces). For example, at least one of a, b, or c may indicate: a, b, c, (a and b), (a and c), (b and c), or (a, b, and c), where a, b, and c may be singular or plural. And/or describes an association relationship between associated objects and indicates that three relationships may exist. For example, A and/or B may indicate the following three cases: Only A exists, both A and B exist, and only B exists, where A and B may be singular or plural. The character / usually indicates an or relationship between the associated objects.

[0272] In addition, unless otherwise specified, ordinal numbers such as first and second in embodiments of this disclosure are intended to distinguish between a plurality of objects, but not to limit an order, a time sequence, priorities, or importance of the plurality of objects. For example, a first container storage management apparatus and a second container storage management apparatus are merely for ease of description, but do not indicate differences in apparatus structures, deployment sequences, importance degrees, and the like of the first container storage management apparatus and the first container storage management apparatus.

[0273] Persons of ordinary skill in the art may understand that all or some of the steps of the foregoing embodiments may be implemented by hardware or a program instructing related hardware. The program may be stored in a computer-readable storage medium. The storage medium may be a read-only memory, a magnetic disk, an optical disc, or the like.

[0274] Finally, it should be noted that the foregoing embodiments are merely intended for describing the technical solutions of the present disclosure, but not for limiting the present disclosure. Although the present disclosure is described in detail with reference to the foregoing embodiments, persons of ordinary skill in the art should understand that they may still make modifications to the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features thereof, without departing from the protection scope of the technical solutions of embodiments of the present disclosure.

Communication Method, Communication Apparatus, and Communication System

Assignee

Inventors

Cpc classification

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H04W74/0833

ELECTRICITY

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H04J13/0055

ELECTRICITY

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H04J13/14

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H04L27/2607

ELECTRICITY

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H04J13/0074

ELECTRICITY

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H04L27/26

ELECTRICITY

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H04W74/0833

ELECTRICITY

Abstract

Claims

Description