Generation, configuration and transmission of chirp-like signals
By introducing linear and continuous sensing signals into the wireless communication system, the problems of sensing signal discontinuity and Zadoff-Chu sequence aliasing are solved, and better self-interference suppression and communication performance are achieved.
Patent Information
- Application Number
- CN202280097927.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-15
- Publication Date
- 2025-02-28
AI Technical Summary
In the existing wireless communication system, the discontinuity of the sensed signal and the aliasing problem of the Zadoff-Chu sequence during the discretization process make it difficult to eliminate self-interference and affect communication performance.
By introducing linear and continuous sensing signals into the wireless communication system, the frequency is ensured to be continuously scanned within the [-B/2, B/2] range, avoid aliasing problems, and generate sensing signals using time shift, frequency shift or mapping methods related to the Zadoff-Chu sequence.
It effectively eliminates the discontinuity in the sensed signal, avoids the aliasing problem of ZC sequences during discretization processing, improves the self-interference suppression ability in the communication system, and improves the communication performance.
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Figure CN119547390A_ABST
Abstract
Description
Technical Field
[0001] This patent document relates to wireless communications. Background Art
[0002] Mobile communication technology is driving the world towards an increasingly connected and networked society. Compared with existing wireless networks, the next generation of systems and communication technologies will need to support a wider range of use case characteristics and provide a more complex and sophisticated range of access requirements and flexibility. Summary of the invention
[0003] Among other things, the patent document discloses techniques related to the generation, configuration, and transmission of chirp-like signals that can be used in wireless communication systems.
[0004] In one example aspect, a wireless communication method is disclosed. The method includes transmitting, by a first wireless device, a sensing signal having a frequency as a continuous function of time within a time period in the range of [-B / 2, B / 2], where B is a transmission bandwidth of the sensing signal.
[0005] In yet another example aspect, a wireless communication device is disclosed that includes a processor configured or operable to perform the above method.
[0006] In yet another example aspect, a computer-readable storage medium is disclosed. The computer-readable storage medium stores codes, which, when executed by a processor, cause the processor to implement the above method.
[0007] These and other aspects are described further throughout this document. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 An example graph illustrating frequencies being swept linearly and continuously across a frequency range is shown.
[0009] Figures 2 to 4 An example graph showing the generation of a linear continuous function by mapping is shown.
[0010] Figure 5 An example of a linear continuous function within [0, T] and [-B / 2, B / 2] with a slope of -1 is shown.
[0011] Figure 6 An example of reusing part of the sensing signal as a channel state information reference signal (CSI-RS) is shown.
[0012] Figure 7 An exemplary block diagram of a hardware platform that may be part of a network device or a communication device is shown.
[0013] Figure 8An example of network communication including a base station (BS) and a user equipment (UE) based on some embodiments of the disclosed technology is shown.
[0014] Figures 9 and 10 is a flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology. DETAILED DESCRIPTION
[0015] The headings of the following sections are used to facilitate understanding of the disclosed subject matter and do not limit the scope of the claimed subject matter in any way. Therefore, one or more features of one section may be combined with one or more features of another section. In addition, for clarity of explanation, 6G or integrated sensing and communication (ISAC) terminology is used. Nevertheless, the technology disclosed in this document is not limited to 6G or ISAC technology and can be used in wireless systems implementing other protocols.
[0016] ISAC is expected to add considerable value to wireless communication systems. Widely deployed communication infrastructure can be enhanced to provide radar services such as traffic control and surveillance, drone detection, and railway obstacle detection. ISAC can also be implemented in various mobile communication devices in autonomous driving, smart home, and healthcare scenarios.
[0017] Communication systems and radar systems utilize electromagnetic waves in two different ways. The idea of dual-function design can be traced back to the 1960s. In recent years, it has attracted increasing research attention, and there are many driving factors, including (1) the spectrum has been well used by two independent systems, and joint spectrum utilization is expected to improve efficiency and flexibility; (2) hardware design has a technical trend of multi-antenna and digital baseband, and the sharing of hardware saves costs; (3) information fusion and mutual reinforcement of the two functions bring performance improvements, especially for autonomous vehicles.
[0018] One problem that exists in the communication infrastructure related to sensing is the self-interference (SI) problem. For radar systems, this problem can be easily solved by using a linear frequency modulated (LFM) signal. The received LFM is dechirped or mixed with the transmitted LFM signal, which converts the strong SI into a direct current (DC) signal. The DC signal can be easily filtered and thus the SI is eliminated. Communication devices can transmit a Zadoff-Chu (ZC) sequence that is similar to the LFM signal. However, since the frequency is not continuously scanned, the dechirping of the ZC sequence performs poorly. Even if OFDM hardware is used to generate a standard LFM signal, the problem still exists.
[0019] In ISAC, the communication hardware is expected to generate a sensing signal. A common sensing signal is the LFM signal, which is expressed as:
[0020]
[0021] Where B and T are the bandwidth and time interval of the LFM signal respectively.
[0022] LFM signals are typically generated by analog methods using a voltage controlled oscillator (VCO) or a surface acoustic wave (SAW) device.
[0023] If it is generated by OFDM digital hardware, it needs to go through a discretization process where the continuous time t is replaced by And the discretized time interval T / M is the inverse of the bandwidth B, which can be expressed as:
[0024]
[0025] Although the discrete signal is a zero autocorrelation sequence, it does not work well with the de-frequencying process because the frequency sweeps from 0 to B / 2 and then aliases to negative frequencies that sweep from -B / 2 to 0. The aliasing problem causes incorrect values at non-integer points because the correct value requires a bandwidth of [0, B]. Similar problems are found when using Zadoff-Chu (ZC) sequences.
[0026] Among other aspects, the present patent application proposes methods and solutions to solve the above problems. The proposed methods and solutions are conducive to eliminating discontinuities in the original signal and avoiding aliasing problems of ZC and other sequences during discretization processing.
[0027] The details of the proposed method are discussed in the following examples.
[0028] Example 1
[0029] Among other things, this section discloses the introduction of "linear" and "continuous" signals.
[0030] Linear
[0031] Linear frequency sweep means phase information The first derivative of is a linear function of t.
[0032] Therefore, the phase information The second derivative of is a constant.
[0033] like Figure 1 As shown, the BS generates a sensing signal whose frequency is linearly swept in the range of [-B / 2, B / 2].
[0034] In such Figure 1 In the example shown, The linear sweep frequency generates As a linear function, and as a constant.
[0035] continuous
[0036] Signals in continuous-time form have the advantage of being easily converted to discrete form.
[0037] Here, "continuous" can be defined with respect to the frequency domain.
[0038] A continuous frequency sweep in [-B / 2, B / 2] means that with a sampling rate or bandwidth of B, all frequencies are aliased in [-B / 2, B / 2] and the sweep in this range is continuous.
[0039] like Figure 1 As shown, the BS generates a sensing signal whose frequency is continuously scanned in the range of [-B / 2, B / 2].
[0040] Figure 1 The upper right portion of discloses an example of a discontinuous scan in [B / 2, B / 2]. Here, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The scan from 0 to B is discontinuous because it is aliased in [-B / 2, B / 2].
[0041] Figure 1 The lower right portion of discloses an example of a discontinuous scan in [B / 2, B / 2]. Here, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The frequency scan from [-B / 2, B / 2] is continuous, which can be linear or nonlinear.
[0042] Example 2
[0043] Among other things, this section discloses examples for generating linear and continuous signals.
[0044] For example, the UE may generate the signal through a time shift operation.
[0045] In this embodiment, the BS or UE generates a sensing signal via:
[0046]
[0047] or
[0048]
[0049] The BS or UE then transmits the generated sensing signal. The same node receives the echo of the sensing signal and uses the transmitted signal to mix with the received echo signal.
[0050] like Figure 2 As shown, a similar signal can be obtained by shifting the signal in time using the following expression:
[0051]
[0052] or
[0053]
[0054] The time shift can be performed in the following manner. First, the second half of the signal in the time period [-T / 2, 0] can be generated using the same formula, using m = -M / 2, -M / 2+1, ..., -1. Second, the complete signal in the time period [-T / 2, T / 2] can be shifted forward in the time domain by a distance of T / 2. In other words, the original signal is shifted from [-T / 2, T / 2] to [0, T].
[0055] In other examples, the time shift offset may be:
[0056] or Where k is an arbitrary integer.
[0057] like Figure 2 As shown, the final signal after frequency shift is continuous and linear in both time and frequency domains.
[0058] Example 3
[0059] Among other things, this section discloses examples for generating linear and continuous signals.
[0060] For example, the UE may generate a signal through a frequency shift operation.
[0061] In one example, the BS may generate a sensing signal via the following expression:
[0062]
[0063] or
[0064]
[0065] Then, the BS transmits the generated sensing signal. Another BS receives an echo of the sensing signal at the same resource location and uses the transmitted signal to mix with the received echo signal. Resource location information in the second BS may be obtained from a higher layer (eg, CN).
[0066] like Figure 3 As shown, a similar signal can be obtained by shifting the frequency of the signal using the following expression:
[0067]
[0068] or
[0069]
[0070] Frequency shifting can be performed in the following manner. First, the first half of the signal in the time period [0, T / 2] can be shifted downward in the frequency domain by a distance of B / 2. In other words, the original signal is shifted from [0, B / 2] to [-B / 2, -0]. Second, the second half of the signal in the time period [T / 2, T] can be shifted upward in the frequency domain by a distance of B / 2. In other words, the original signal is shifted from [B / 2, B] to [0, B / 2].
[0071] In other examples, the frequency shift offset may be:
[0072] or Where k is an arbitrary integer.
[0073] like Figure 3 As shown, the final signal after frequency shift is continuous and linear in both time and frequency domains.
[0074] Example 4
[0075] Among other things, this section discloses examples for generating linear and continuous signals.
[0076] For example, the UE may generate the signal through a mapping operation of one of linear frequency modulation (LFM) signals.
[0077] In this embodiment, if Figure 4 As shown, the BS can generate a sensing signal by exchanging the first half and the second half of the time domain or frequency domain. The corresponding expression is:
[0078]
[0079] After generating the sensing signal using the above method, the UE can transmit the generated sensing signal in the resources allocated by the BS. In a wireless communication environment, some targets may backscatter the sensing signal. The BS receives the echo signal or the backscattered signal from the target at the allocated resource. The BS receiver generates a signal using the same method and mixes it with the received echo signal. In this way, the self-interference signal transmitted directly from the transmitting antenna to the receiving antenna is converted into a DC signal, and the echo signal is converted into the sum of single-tone signals, where the frequency of the single-tone signal is determined by the target distance. The BS can then obtain the resource location and speed information of the target through processing operations.
[0080] Example 5
[0081] Among other things, this section discloses examples for generating linear and continuous signals.
[0082] For example, the UE may generate a signal by a mapping method related to a Zadoff-Chu sequence.
[0083] In this embodiment, the wireless node (eg, UE) may generate a sensing signal by setting parameters associated with the sequence function. For example, the UE may set u and C in an equation associated with the ZC sequence. v The value of .
[0084] In one example, the value of parameter u is set to u=1 or -1, and the C of the following ZC sequence expression v The value is set to C v = -M / 2, -(M+1) / 2 or -(M-1) / 2:
[0085] xu , v(n)=xu((n+Cv)mod M),
[0086]
[0087] After generating the sensing signal using the above method, the UE can transmit the generated sensing signal in the resources allocated by the BS. In a wireless communication system, some targets may backscatter the sensing signal. The BS receives the echo signal or the backscattered signal from the target at the allocated resource. The BS receiver generates a signal using the same method and mixes it with the received echo signal. In this way, the self-interference signal transmitted directly from the transmitting antenna to the receiving antenna is converted into a DC signal, and the echo signal is converted into the sum of single-tone signals, where the frequency of the single-tone signal is determined by the target distance. The BS can then obtain the resource location and speed information of the target through processing operations.
[0088] Figure 5The frequency spectrogram is shown for the example when u=-1, which represents the scenario of frequency sweeping in the negative direction.
[0089] Example 6
[0090] Among other things, this embodiment discloses examples involving reusing at least a portion of a sensed signal.
[0091] In some examples, at least a portion of the sensing signal may be reused as a reference signal or a synchronization signal.
[0092] For example, Figure 6 As shown, the first symbol and the fifth symbol of all 8 symbols of the sensing signal are also used as a channel state information reference signal (CSI-RS) to improve spectrum efficiency.
[0093] Figure 7 An exemplary block diagram of a hardware platform 700 is shown, which may be part of a network device (e.g., a base station) or a communication device (e.g., a user equipment (UE)). The hardware platform 700 includes at least one processor 710 and a memory 705 having instructions stored thereon. The instructions, when executed by the processor 410, configure the hardware platform 700 to perform Figures 1 to 6 The operations described in the various embodiments described in and in this patent document. Transmitter 715 transmits or sends information or data to another device. For example, a network device transmitter can send a message to a user device. Receiver 720 receives information or data transmitted or sent by another device. For example, a user device can receive a message from a network device.
[0094] The above-described embodiments will be applied to network communications. Figure 8 An example of a communication system (e.g., a 6G or NR cellular network) including a base station 820 and one or more user equipment (UE) 811, 812, and 813 is shown. In some embodiments, the UE uses a communication link to the network (sometimes referred to as an uplink direction, as depicted by dashed arrows 831, 832, 833) to access the BS (e.g., the network), which then enables subsequent communication from the BS to the UE (e.g., shown in the direction from the network to the UE, sometimes referred to as a downlink direction, as shown by arrows 841, 842, 843). In some embodiments, the BS sends information to the UE (sometimes referred to as a downlink direction, as depicted by arrows 841, 842, 843), which then enables subsequent communication from the UE to the BS (e.g., shown in the direction from the UE to the BS, sometimes referred to as an uplink direction, as shown by dashed arrows 831, 832, 833). The UE can be, for example, a smartphone, a tablet, a mobile computer, a machine-to-machine (M2M) device, an Internet of Things (IoT) device, etc.
[0095] Fig. 9 An example flow chart representation of a method for wireless communication in accordance with one or more embodiments of the present technology is shown. Operation 902 includes transmitting, by a first wireless device, a sensing signal having a frequency as a continuous function of time within a time period in the range of [-B / 2, B / 2], where B is a transmission bandwidth of the sensing signal.
[0096] Fig.10 An example flow chart representation of a method for wireless communication according to one or more embodiments of the present technology is shown. Operation 1002 includes receiving, by a second wireless device, a sensing signal having a frequency as a continuous function of time within a time period in the range of [-B / 2, B / 2], where B is a transmission bandwidth of the sensing signal. Operation 1004 includes performing an operation based on the sensing signal.
[0097] Figures 9 and 10 Various preferred embodiments and additional features of the above method are as follows. Further examples are described with reference to Examples 1 to 6.
[0098] In one example aspect, a wireless communication method is disclosed. The method includes transmitting, by a first wireless device, a sensing signal having a frequency as a continuous function of time within a time period in the range of [-B / 2, B / 2], where B is a transmission bandwidth of the sensing signal.
[0099] In another example aspect, another wireless communication method is disclosed. The method includes receiving, by a second wireless device, a sensing signal having a frequency as a continuous function of time within a time period in the range of [-B / 2, B / 2], where B is a transmission bandwidth of the sensing signal; and operating based on the sensing signal.
[0100] In some embodiments, the frequency is swept linearly and continuously in the range of [-B / 2, B / 2].
[0101] In some embodiments, the sensing signal is generated by at least one of: 1) a time shift operation, 2) a frequency shift operation, 3) a mapping operation of one of a linear frequency modulation (LFM) signal, or 4) a mapping method related to a Zadoff-Chu sequence.
[0102] In some embodiments, the sensing signal is generated by setting parameters of a Zadoff-Chu (ZC) sequence generation method.
[0103] In some embodiments, by setting the u and C of the ZC sequence v The value is used to generate the sensing signal, and the ZC sequence is expressed as:
[0104] x u,v (n) = x u ((n+Cv )modL)
[0105]
[0106] In some embodiments, u=1 or -1, where C v =-M / 2, -(M+1) / 2 or -(M-1) / 2.
[0107] In some embodiments, the sensing signal is generated by at least one of the following: 1) 2) 3) or 4)
[0108]
[0109] In some embodiments, at least a portion of the sense signal is used as a reference signal or a synchronization signal.
[0110] It should be understood that this document discloses methods and apparatus related to generating chirp-like signals that can be used in ISAC or other communication systems. LFM signals are introduced to solve the SI problem. Communications use ZC sequences similar to LFM signals to achieve similar goals. The de-modulation processing of ZC sequences performs poorly during discrete scanning. This patent application proposes methods and solutions to solve the above problems. The proposed methods and solutions are conducive to eliminating discontinuities in the original signal and avoiding aliasing problems between ZC and other sequences during discretization processing.
[0111] The disclosed embodiments and other embodiments, modules and functional operations described in this document may be implemented in digital electronic circuit systems, or in computer software, firmware or hardware, including the structures disclosed in this document and their structural equivalents, or in a combination of one or more of them. The disclosed embodiments and other embodiments may be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium, for execution by a data processing device or for controlling the operation of the data processing device. The computer-readable medium may be a machine-readable storage device, a machine-readable storage substrate, a storage device, a composition that affects a machine-readable propagation signal, or a combination of one or more of them. The term "data processing device" encompasses all devices, equipment and machines for processing data, such as a programmable processor, a computer or multiple processors or computers. In addition to hardware, the device may also include code that creates an execution environment for the computer program under consideration, such as code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagation signal is an artificially generated signal, such as a machine-generated electrical signal, an optical signal, or an electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.
[0112] A computer program (also referred to as a program, software, software application, script, or code) may be written in any form of programming language, including compiled or interpreted languages, and it may be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for a computing environment. A computer program does not necessarily correspond to a file in a file system. A program may be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program under consideration, or in multiple collaborative files (e.g., files storing one or more modules, subroutines, or portions of code). A computer program may be deployed to be executed on one computer or multiple computers located at one site or distributed across multiple sites and interconnected by a communications network.
[0113] The processes and logic flows described in this document may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by special purpose logic circuitry, and apparatus may also be implemented as special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).
[0114] For example, processors suitable for executing computer programs include general-purpose microprocessors and special-purpose microprocessors, as well as any one or more processors of any kind of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The basic elements of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Typically, a computer will also include or be operably coupled to one or more large-capacity storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data to receive data from or transfer data to, or both. However, a computer need not have such a device. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor storage devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD ROM and DVD-ROM optical disks. The processor and memory may be supplemented by or incorporated into a dedicated logic circuit system.
[0115] Although this document contains many details, these should not be interpreted as limitations on the scope of the claimed invention or the scope of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features described in this document in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. In addition, although the above-mentioned features may be described as working in certain combinations and even initially claimed as such, in some cases, one or more features from the combination may be deleted from the combination, and the combination may involve sub-combinations or variations of sub-combinations. Similarly, although operations are described in a particular order in the accompanying drawings, this should not be understood as requiring that the operations be performed in the particular order or sequence shown, or that all the operations shown be performed to obtain the desired results.
[0116] Only some examples and implementations are disclosed. Variations, modifications and enhancements may be made to the described examples and implementations and other implementations based on what is disclosed.
Claims
1. A method for wireless communication, the method comprising: A sensing signal having a frequency as a continuous function of time is transmitted by the first wireless device within a time period in the range of [-B / 2, B / 2], where B is a transmission bandwidth of the sensing signal.
2. A method for wireless communication, the method comprising: receiving, by a second wireless device, a sensing signal having a frequency as a continuous function of time within a time period in the range of [-B / 2, B / 2], where B is a transmission bandwidth of the sensing signal; as well as An operation is performed based on the sensed signal.
3. The method according to claim 1 or 2, wherein: The frequency is swept linearly and continuously in the range of [-B / 2, B / 2].
4. The method according to claim 1 or 2, wherein: The sensing signal is generated by at least one of: 1) a time shift operation, 2) a frequency shift operation, 3) a mapping operation of one of a linear frequency modulation (LFM) signal, or 4) a mapping method associated with a Zadoff-Chu sequence.
5. The method according to claim 1 or 2, wherein: The sensing signal is generated by setting parameters of a Zadoff-Chu (ZC) sequence generation method.
6. The method according to claim 5, wherein: The sensing signal is obtained by setting the u and C of the ZC sequence. v To generate, the ZC sequence is expressed as: x u,v (n)=x u ((n+C v )modL) 7. The method according to claim 6, wherein: u=1 or -1, where C v =-M / 2, -(M+1) / 2 or -(M-1) / 2.
8. The method according to claim 1 or 2, wherein: The sensing signal is generated by at least one of the following: 1) 2) 3) or 4) 9. The method according to claim 1 or 2, wherein: At least a portion of the sensing signal is used as a reference signal or a synchronization signal.
10. An apparatus for a communication network, the apparatus comprising: A processor configured to implement the method according to any one of claims 1 to 9.
11. A computer-readable storage medium having codes stored thereon, which, when executed by a processor, cause the processor to implement the method according to any one of claims 1 to 9.