Cell switching method and device

Abstract

The invention provides a cell switching method and device, and belongs to the technical field of communication. The cell switching method is applied to a source base station, and comprises the following steps: sending a sensing signal, receiving an echo signal of the sensing signal reflected by a terminal, and determining the current position and the moving speed of the terminal according to the echo signal; determining a target base station of the terminal according to the current position and the moving speed of the terminal, and sending information of the target base station to the terminal; determining whether the terminal enters a pre-switching range or not according to the current position, the moving speed and the switching time delay of the terminal; and after the terminal enters the pre-switching range, sending user information of the terminal to the target base station. According to the invention, the switching time can be shortened and the switching success rate can be improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to a cell handover method and apparatus. Background Art

[0002] With the rapid development of the low-altitude economy, emerging business scenarios such as drone delivery, air taxis, and smart city surveillance are constantly emerging. To ensure the safety of low-altitude drone operations in these application scenarios, not only a stable and reliable basic communication capability needs to be provided for low-altitude drones, but also advanced sensing and recognition capabilities are required.

[0003] With the development of the fifth-generation mobile communication system (5G) and its subsequent evolved technologies, the concept of integrated sensing and communication (ISAC) has been proposed, aiming to achieve the integration of wireless communication and environmental sensing functions. ISAC technology can support both communication and sensing services on the same spectrum resource, which not only improves the spectrum efficiency but also provides new possibilities for future intelligent Internet of Things (IoT) applications. Summary of the Invention

[0004] Embodiments of the present invention provide a cell handover method and apparatus, which can shorten the handover time and improve the handover success rate.

[0005] The embodiments of the present invention provide the following technical solutions:

[0006] On the one hand, a cell handover method is provided, which is applied to a source base station and includes:

[0007] Sending a sensing signal, receiving an echo signal reflected by a terminal from the sensing signal, and determining the current position and moving speed of the terminal according to the echo signal;

[0008] Determining a target base station of the terminal according to the current position and moving speed of the terminal, and sending information of the target base station to the terminal;

[0009] Determining whether the terminal enters a pre-handover range according to the current position, moving speed, and handover delay of the terminal;

[0010] After the terminal enters the pre-handover range, sending user information of the terminal to the target base station.

[0011] In some embodiments, the sensing signal is carried by a primary synchronization signal PSS and / or a secondary synchronization signal SSS in a synchronization signal block SSB; or

[0012] The sensing signal is carried by a demodulation reference signal DMRS in the SSB.

[0013] In some embodiments, determining whether the terminal enters the pre - handover range according to the current position, moving speed, and handover delay of the terminal includes:

[0014] When the distance d between the terminal and the target base station ue satisfies the following formula, it is determined that the terminal enters the pre - handover range:

[0015] d ue -Δd≤d pre

[0016] where d pre is a preset pre - handover threshold, and Δd is determined by the following formula:

[0017]

[0018] v*τ d =Δd

[0019] where v is the moving speed of the terminal, and τ d is the overall delay, and τ is the handover delay.

[0020] In some embodiments, the method further includes:

[0021] Determining a target waveform used for the terminal's communication according to the moving speed of the terminal, and sending waveform information of the target waveform to the terminal.

[0022] In some embodiments, when the moving speed of the terminal is not greater than a preset speed threshold, the target waveform is an orthogonal frequency - division multiplexing (OFDM) waveform;

[0023] When the moving speed of the terminal is greater than the preset speed threshold, the target waveform is an orthogonal time - frequency - space (OTFS) waveform.

[0024] In some embodiments, the waveform information indicates that during the process of switching from the OFDM waveform to the OTFS waveform, the sub - carrier spacing gradually increases;

[0025] The waveform information indicates that during the process of switching from the OFDM waveform to the OTFS waveform, the sub - carrier spacing gradually decreases.

[0026] An embodiment of the present invention further provides a cell handover method applied to a terminal, including:

[0027] Receiving a sensing signal sent by a source base station and reflecting an echo signal to the source base station;

[0028] Receiving information of a target base station sent by the source base station;

[0029] Monitor the reference signal receiving power of the source base station and the reference signal receiving power of the target base station;

[0030] When the reference signal receiving power of the target base station exceeds the reference signal receiving power of the source base station, switch to the target base station.

[0031] An embodiment of the present invention further provides a cell handover device, which is applied to a source base station and includes:

[0032] A processing module, configured to send a sensing signal, receive an echo signal reflected by a terminal from the sensing signal, and determine the current position and moving speed of the terminal according to the echo signal;

[0033] A determination module, configured to determine a target base station of the terminal according to the current position and moving speed of the terminal, and send information about the target base station to the terminal;

[0034] A judgment module, configured to determine whether the terminal enters a pre-handover range according to the current position, moving speed and handover delay of the terminal;

[0035] A sending module, configured to send user information of the terminal to the target base station after the terminal enters the pre-handover range.

[0036] In some embodiments, the cell handover device further includes:

[0037] A waveform switching module, configured to determine a target waveform used for communication of the terminal according to the moving speed of the terminal, and send waveform information of the target waveform to the terminal.

[0038] An embodiment of the present invention further provides a cell handover device, which is applied to a terminal and includes:

[0039] A transmission module, configured to receive a sensing signal sent by a source base station and reflect an echo signal to the source base station; receive information about a target base station sent by the source base station;

[0040] A monitoring module, configured to monitor the reference signal receiving power of the source base station and the reference signal receiving power of the target base station;

[0041] A handover module, configured to switch to the target base station when the reference signal receiving power of the target base station exceeds the reference signal receiving power of the source base station.

[0042] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the cell handover method described above are implemented.

[0043] An embodiment of the present invention also provides a computer program product, including computer instructions, which implement the steps of the cell handover method as described above when executed by a processor.

[0044] The embodiments of the present invention have the following beneficial effects:

[0045] In the above solution, a sensing signal is sent to the terminal, and an echo signal reflected by the terminal from the sensing signal is received. By processing the echo signal, the current position and moving speed of the terminal can be determined. According to the current position and moving speed of the terminal, the target base station for handover can be determined. After the terminal enters the pre - handover range, the user information of the terminal is sent to the target base station in advance. This can enable the target base station to perform resource allocation and handover preparation in advance, shorten the time required for handover, reduce handover latency, and improve the handover success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic flowchart of the cell handover method applied to the source base station in the embodiment of the present invention;

[0047] Figure 2 It is a schematic diagram of processing the echo signal in the embodiment of the present invention;

[0048] Figure 3 It is a schematic diagram of the frame structure of the SSB;

[0049] Figure 4 It is a schematic flowchart of the cell handover method applied to the terminal in the embodiment of the present invention;

[0050] Figure 5 It is a block diagram of the structure of the cell handover device applied to the source base station in the embodiment of the present invention;

[0051] Figure 6 It is a block diagram of the structure of the cell handover device applied to the terminal in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] To make the technical problems, technical solutions, and advantages to be solved by the embodiments of the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0053] Through the integration of communication and sensing functions, the ISAC technology can achieve more intelligent signal processing and resource management. However, the existing ISAC technology mainly focuses on signal transmission and reception, and relatively little research has been done on the optimization of cell handover.

[0054] Cell handover refers to the process in which a mobile terminal seamlessly switches between different base stations or cells, ensuring communication continuity and quality of service (QoS). In traditional mobile communication systems, cell handover is mainly based on the measurement of signal strength or quality. However, the existing cell handover technologies have the following problems:

[0055] 1. Handover delay: In high user density areas, the processing of handover requests may be delayed due to network congestion, affecting the user experience.

[0056] 2. Uneven signal coverage: Due to factors such as building blockage and terrain undulation, there are blind spots in signal coverage, resulting in unstable signals during handover and reducing the handover success rate.

[0057] 3. Uneven resource allocation: During peak hours, the cell resource allocation may be uneven, resulting in some user devices being unable to obtain sufficient bandwidth and quality of service.

[0058] In addition, in high-speed mobile scenarios, traditional cell handover strategies are difficult to adapt to the rapidly changing channel environment, resulting in handover delay and packet loss. At the same time, the handover strategies in low-speed mobile scenarios are inefficient in high-speed scenarios.

[0059] Embodiments of the present invention provide a cell handover method and apparatus, which can shorten the time required for handover and improve the handover success rate.

[0060] Embodiments of the present invention provide a cell handover method, which is applied to a source base station, as Figure 1 shown, and includes:

[0061] Step 101: Send a sensing signal, receive the echo signal reflected by the terminal from the sensing signal, and determine the current position and moving speed of the terminal according to the echo signal;

[0062] The source base station in this embodiment can be an ISAC base station. In addition to having basic communication functions, the ISAC base station also has sensing capabilities. The sensing capabilities of the ISAC base station can be used to send sensing signals to the terminal, and by analyzing the echo signals returned by the terminal, the moving speed and position of the terminal can be estimated in real time. The ISAC base station is equipped with a dedicated ISAC signal processing module, as Figure 2 shown, which can receive and process communication signals and echo signals simultaneously. After receiving the communication signals and echo signals, the ISAC signal processing module first processes the communication signals and echo signals using a low-noise amplifier (LNA), and then performs digital down-conversion and analog-to-digital conversion on the communication signals and echo signals.

[0063] Specifically, during the communication between the source base station and the terminal, the signals received by the source base station include the uplink communication signal from the terminal and the echo signal. The echo signal contains the reflection, scattering information of the terminal and the Doppler frequency shift, and the Doppler frequency shift is directly related to the moving speed of the terminal. The source base station can use existing radar signal processing methods such as two-dimensional fast Fourier transform (2D-FFT) to process the echo signal reflected by the terminal, obtain parameters such as distance, speed, and angle, and thus can know the location information of the terminal.

[0064] Compared with the traditional one-dimensional fast Fourier transform (1D-FFT), 2D-FFT can analyze the time-frequency characteristics and spatial characteristics of the signal simultaneously, so as to more accurately estimate the speed and direction of the terminal. By analyzing the specific frequency components in the 2D-FFT result, the moving speed of the terminal can be estimated; specifically, the magnitude of the Doppler frequency shift contained in the echo signal is proportional to the moving speed of the terminal, and by calculating these frequency shifts, the speed information of the terminal can be accurately obtained.

[0065] Step 102: Determine the target base station of the terminal according to the current position and moving speed of the terminal, and send the information of the target base station to the terminal;

[0066] Specifically, the moving trajectory of the terminal can be predicted according to the current position and moving speed of the terminal, the base station on the moving trajectory is determined as the target base station, and the information of the target base station such as the identifier and location of the target base station is sent to the terminal.

[0067] Step 103: Determine whether the terminal enters the pre-switching range according to the current position, moving speed and handover delay of the terminal;

[0068] In this embodiment, the source base station determines the pre-switching range based on the current position, moving speed and handover delay (the delay caused by the handover algorithm) of the terminal, and triggers the pre-switching step when the user enters the pre-switching range.

[0069] Specifically, when the distance d ue between the terminal and the target base station satisfies the following formula, it is determined that the terminal enters the pre-switching range:

[0070] d ue -Δd ≤ d pre

[0071] where d pre is the preset pre-switching threshold, and the value of d pre can be adjusted according to the terminal nature and the actual scenario. Δd is determined by the following formula:

[0072]

[0073] v * τd = Δd

[0074] where v is the moving speed of the terminal, and τ d is the overall time delay, and τ is the handover time delay.

[0075] Step 104: After the terminal enters the pre - handover range, send the user information of the terminal to the target base station.

[0076] When it is determined that the pre - handover step needs to be executed, the source base station sends the user key information of the terminal (including the resources required by the terminal and the currently used frequency band, etc.) to the target base station in advance, so that the target base station reserves the corresponding resources and prepares for frequency handover, ensuring the continuity and integrity of data. After receiving the user information of the terminal, the target base station starts to prepare for resource allocation and connection establishment.

[0077] In this embodiment, a sensing signal is sent to the terminal, and the echo signal reflected by the terminal from the sensing signal is received. By processing the echo signal, the current position and moving speed of the terminal can be determined. According to the current position and moving speed of the terminal, the target base station for handover can be determined. After the terminal enters the pre - handover range, the user information of the terminal is sent to the target base station in advance, so that the target base station can perform resource configuration and handover preparation in advance, shortening the time required for handover, reducing handover delay and increasing handover success rate.

[0078] To support the functions of ISAC, a new frame structure needs to be designed to meet the requirements of communication and sensing. Traditional wireless communication systems usually adopt a fixed frame structure, but in the ISAC system, the frame structure needs to flexibly allocate resource blocks to support both data transmission and sensing tasks simultaneously.

[0079] In this embodiment, part of the signals in the Synchronization Signal and PBCH block (SSB) can be used as the sensing signal to increase the sensing of users without affecting communication. Figure 3It is a schematic diagram of the SSB frame structure. In a related communication system, the Primary Synchronization Signals (PSS), Secondary Synchronization Signals (SSS), and Physical Broadcast Channel (PBCH) together constitute an SSB (SS / PBCH block). In the time domain, the SS / PBCH block consists of 4 Orthogonal Frequency Division Multiplexing (OFDM) symbols, numbered in ascending order from 0 to 3 within the SS / PBCH block. In the frequency domain, the SS / PBCH block consists of 240 consecutive subcarriers, with subcarrier numbers increasing sequentially from 0 to 239.

[0080] The time / frequency domain position information of PSS, SSS, and PBCH in each SSB is as follows:

[0081] PSS: In the time domain, it is located at the position of the 0th OFDM symbol in the SSB block, and in the frequency domain, it occupies 127 subcarriers between 56 and 182.

[0082] SSS: In the time domain, it is located at the position of the 2nd OFDM symbol in the SSB block, and in the frequency domain, it occupies 127 subcarriers between 56 and 182.

[0083] PBCH: When occupying the positions of the 1st and 3rd OFDM symbols in the SSB block, it occupies 240 subcarriers between 0 and 239 in the frequency domain; when occupying the 2nd symbol position in the SSB block, it occupies 96 subcarriers between 0 and 47 and between 192 and 239 in the frequency domain.

[0084] In some embodiments, the PSS of the SSB can be directly used as a sensing signal, and the PSS can be processed as a sensing signal at the receiving end. In the SSB, 127 subcarriers in the center frequency band of the subcarriers are filled with PSS data (127 subcarriers between 56 and 182), and no data is filled in the upper and lower frequency bands of the center frequency band (56 subcarriers between 0 and 55 and 57 subcarriers between 183 and 239). If the PSS is used as a sensing signal to complete the radar detection function, the PSS data can be directly used as the sensing signal.

[0085] There are a total of 127 subcarriers in the PSS filled with communication data, and the filled data has good autocorrelation. As can be seen from the following formula, the sensing distance resolution R res and the maximum sensing distance R max are inversely proportional to the sensing bandwidth Δf, where Nc where \(N\) is the number of subcarriers occupied by the sensing signal, and \(c_0\) is the speed of light.

[0086]

[0087] Therefore, when the subcarrier spacing is 30 kHz (sub6GHz band) and 120 kHz (mmWave band), the sensing distance resolution (i.e., the radar detection distance resolution of the integrated waveform) is 39.37 m and 9.84 m respectively. When the subcarrier spacing is 30 kHz (sub6GHz band) and 120 kHz (mmWave band), the maximum sensing distance (i.e., the maximum ranging range of the integrated sensing algorithm for detecting distance information) is 5 km and 1.25 km respectively.

[0088] In some embodiments, the SSS of the SSB can also be directly used as the sensing signal, and the SSS can be processed as the sensing signal at the receiving end.

[0089] In some embodiments, the SSS and PSS of the SSB can also be jointly used as the sensing signal, and the PSS and SSS can be processed as the sensing signal at the receiving end. The joint use of PSS and SSS as the sensing signal can improve the radar data refresh rate and the sensing accuracy.

[0090] In some embodiments, the DMRS symbol bit can also be used as the sensing signal. The position of the DMRS corresponding to the PBCH is related to the cell physical layer identifier (ID). On symbols 1 and 3 of the SSB, there is one DMRS signal every 4 subcarriers among 240 subcarriers, and the starting position of the DMRS signal depends on the result \(v\) of taking the modulo of the cell physical layer cell ID number with 4. On symbol 2, there is one DMRS signal every 4 subcarriers among subcarriers 0 - 47 and subcarriers 192 - 239. Similarly, the starting position of the DMRS signal depends on the result \(v\) of taking the modulo of the cell physical layer ID number with 4. There are 60 DMRSs (0 + \(v\), 4 + \(v\), 8 + \(v\), …, 236 + \(v\)) in each of symbols 1 and 3. Therefore, using the DMRS symbol for radar signal detection and processing can improve the radar data refresh rate and the sensing accuracy.

[0091] The carrier spacing of the DMRS is \(4\Delta f\). When the subcarrier spacing is 30 kHz (sub6GHz band) and 120 kHz (mmWave band), the carrier spacing of the DMRS is 120 kHz and 480 kHz, the sensing distance resolution (i.e., the radar detection distance resolution of the integrated waveform) is 20.83 m and 5.20 m respectively, and the maximum sensing distance (i.e., the maximum ranging range of the integrated sensing algorithm for detecting distance information) is 1.25 km and 0.312 km respectively.

[0092] In some embodiments, the cell handover method further includes:

[0093] Determine a target waveform used for the terminal's communication according to the moving speed of the terminal, and send waveform information of the target waveform to the terminal.

[0094] Based on the moving speed of the terminal, waveform selection is performed in this embodiment, and the most suitable waveform can be dynamically selected according to the moving speed of the terminal to optimize communication performance.

[0095] In some embodiments, a preset speed threshold can be used to distinguish between a low-speed scenario and a high-speed scenario. When the moving speed of the terminal is not greater than the preset speed threshold, it is considered to be in a low-speed scenario; when the moving speed of the terminal is greater than the preset speed threshold, it is considered to be in a high-speed scenario. Specifically, the preset speed threshold can be 100 km / h. Of course, the value of the preset speed threshold can also be adjusted according to actual needs.

[0096] When the moving speed of the terminal is not greater than the preset speed threshold, the target waveform can be an orthogonal frequency division multiplexing (OFDM) waveform, which can optimize spectral efficiency and reduce interference;

[0097] When the moving speed of the terminal is greater than the preset speed threshold, the target waveform is an orthogonal time-frequency-space (OTFS) waveform, which can improve signal stability under high-speed movement.

[0098] In a low-speed scenario, the OFDM waveform can effectively resist frequency-selective fading and reduce the influence of multipath interference through spectral dispersion, thereby providing stable communication quality. In a high-speed scenario, the OTFS waveform can better adapt to a time-varying channel, reduce the influence of Doppler frequency shift through signal processing in the time-frequency space, and maintain signal integrity.

[0099] During the waveform handover process, the network-side device needs to adjust parameters accordingly, such as subcarrier spacing, modulation mode, coding strategy, etc., to adapt to the characteristics of different waveforms. The source base station can send the subcarrier spacing, modulation mode, coding strategy, etc. as waveform information of the target waveform to the terminal.

[0100] In addition, in order to reduce signal distortion during the handover process, it is necessary to smoothly adjust the subcarrier spacing. In some embodiments, the waveform information indicates that during the process of switching from the OFDM waveform to the OTFS waveform, the subcarrier spacing gradually increases, which can smoothly adjust the subcarrier spacing and reduce signal distortion during the handover process; the waveform information indicates that during the process of switching from the OFDM waveform to the OTFS waveform, the subcarrier spacing gradually decreases, which can smoothly adjust the subcarrier spacing and reduce signal distortion during the handover process.

[0101] An embodiment of the present invention further provides a cell handover method, which is applied to a terminal. For example, Figure 4 as shown, it includes:

[0102] Step 201: Receive the sensing signal sent by the source base station and reflect an echo signal back to the source base station;

[0103] Step 202: Receive the information of the target base station sent by the source base station;

[0104] Step 203: Monitor the reference signal received power of the source base station and the reference signal received power of the target base station;

[0105] Step 204: When the reference signal received power of the target base station exceeds the reference signal received power of the source base station, switch to the target base station.

[0106] In this embodiment, after receiving the information of the target base station, the terminal continuously monitors the reference signal received power (RSRP) of the source base station and the RSRP of the target base station. When the RSRP from the target base station exceeds the RSRP of the source base station, the terminal immediately performs cell handover, establishes a channel connection with the target base station, and releases the channel resources with the source base station.

[0107] An embodiment of the present invention further provides a cell handover device, which is applied to a source base station. For example, Figure 5 as shown, it includes:

[0108] A processing module 31, configured to send a sensing signal, receive the echo signal reflected by the terminal from the sensing signal, and determine the current position and moving speed of the terminal according to the echo signal;

[0109] The source base station in this embodiment may be an ISAC base station. In addition to having the basic communication function, the ISAC base station also has a sensing ability. The sensing ability of the ISAC base station can be used to send a sensing signal to the terminal, and by analyzing the echo signal returned by the terminal, the moving speed and position of the terminal can be estimated in real time. The ISAC base station is equipped with a dedicated ISAC signal processing module. For example, Figure 2 as shown, it can receive and process communication signals and echo signals simultaneously. After receiving the communication signal and the echo signal, the ISAC signal processing module first processes the communication signal and the echo signal using a low-noise amplifier (LNA), and then performs digital down-conversion and analog-to-digital conversion on the communication signal and the echo signal.

[0110] Specifically, during the communication between the source base station and the terminal, the signals received by the source base station include the uplink communication signal from the terminal and the echo signal. The echo signal contains the reflection and scattering information of the terminal as well as the Doppler frequency shift, which is directly related to the moving speed of the terminal. The source base station can use existing radar signal processing methods such as two-dimensional fast Fourier transform (2D-FFT) to process the echo signal reflected by the terminal, obtain parameters such as distance, speed, and angle, and thus can obtain the location information of the terminal.

[0111] Compared with the traditional one-dimensional fast Fourier transform (1D-FFT), 2D-FFT can analyze the time-frequency characteristics and spatial characteristics of the signal simultaneously, so as to more accurately estimate the speed and direction of the terminal. By analyzing the specific frequency components in the 2D-FFT result, the moving speed of the terminal can be estimated; specifically, the magnitude of the Doppler frequency shift contained in the echo signal is proportional to the moving speed of the terminal. By calculating these frequency shifts, the speed information of the terminal can be accurately obtained.

[0112] A determination module 32, configured to determine the target base station of the terminal according to the current location and moving speed of the terminal, and send the information of the target base station to the terminal;

[0113] Specifically, the moving trajectory of the terminal can be predicted according to the current location and moving speed of the terminal, the base station on the moving trajectory is determined as the target base station, and the information of the target base station such as the identifier and location of the target base station is sent to the terminal.

[0114] A judgment module 33, configured to determine whether the terminal enters the pre-switching range according to the current location, moving speed and switching delay of the terminal;

[0115] In this embodiment, the source base station determines the pre-switching range based on the current location, moving speed and switching delay (the delay caused by the switching algorithm) of the terminal, and triggers the pre-switching step when the user enters the pre-switching range.

[0116] A sending module 34, configured to send the user information of the terminal to the target base station after the terminal enters the pre-switching range.

[0117] When it is determined that the pre-switching step needs to be executed, the source base station sends the key user information of the terminal (including the resources required by the terminal and the currently used frequency band, etc.) to the target base station in advance, so that the target base station reserves the corresponding resources and prepares for frequency switching, ensuring the continuity and integrity of the data. After receiving the user information of the terminal, the target base station starts to prepare for resource allocation and connection establishment.

[0118] In this embodiment, a sensing signal is sent to the terminal, and an echo signal reflected by the terminal after receiving the sensing signal is received. By processing the echo signal, the current position and moving speed of the terminal can be determined. According to the current position and moving speed of the terminal, the target base station for the terminal to switch to can be determined, and after the terminal enters the pre-switching range, the user information of the terminal is sent to the target base station in advance. This can enable the target base station to perform resource allocation and handover preparation in advance, shorten the time required for handover, reduce handover latency, and improve the handover success rate.

[0119] In some embodiments, the sensing signal is carried by the primary synchronization signal PSS and / or the secondary synchronization signal SSS in the synchronization signal block SSB; or

[0120] The sensing signal is carried by the demodulation reference signal DMRS in the SSB.

[0121] In some embodiments, the determination module 33 is specifically configured to determine that the terminal enters the pre-switching range when the distance d ue between the terminal and the target base station satisfies the following formula:

[0122] d ue -Δd ≤ d pre

[0123] where d pre is a preset pre-switching threshold, and Δd is determined by the following formula:

[0124]

[0125] v * τ d = Δd

[0126] where v is the moving speed of the terminal, and τ d is the overall time delay, and τ is the handover time delay.

[0127] In some embodiments, the cell handover device further includes:

[0128] A waveform switching module, configured to determine the target waveform used for the terminal's communication according to the moving speed of the terminal, and send the waveform information of the target waveform to the terminal.

[0129] This embodiment selects the waveform based on the moving speed of the terminal, and can dynamically select the most suitable waveform according to the moving speed of the terminal to optimize the communication performance.

[0130] In some embodiments, when the moving speed of the terminal is not greater than the preset speed threshold, the target waveform is the orthogonal frequency division multiplexing OFDM waveform;

[0131] When the moving speed of the terminal is greater than a preset speed threshold, the target waveform is an orthogonal time-frequency-space OTFS waveform.

[0132] In a low-speed scenario, the OFDM waveform can effectively resist frequency-selective fading, reduce the impact of multipath interference through spectral dispersion, and thus provide stable communication quality. In a high-speed scenario, the OTFS waveform can better adapt to a time-varying channel, reduce the impact of Doppler frequency shift through signal processing in the time-frequency space, and maintain the integrity of the signal.

[0133] To reduce signal distortion during the handover process, it is necessary to smoothly adjust the subcarrier spacing. In some embodiments, the waveform information indicates that the subcarrier spacing gradually increases during the handover from the OFDM waveform to the OTFS waveform; the waveform information indicates that the subcarrier spacing gradually decreases during the handover from the OFDM waveform to the OTFS waveform.

[0134] An embodiment of the present invention also provides a cell handover device, which is applied to a terminal, as Figure 6 shown, including:

[0135] A transmission module 41, configured to receive a sensing signal sent by a source base station, and reflect an echo signal back to the source base station; receive information of a target base station sent by the source base station;

[0136] A monitoring module 42, configured to monitor the reference signal received power of the source base station and the reference signal received power of the target base station;

[0137] A handover module 43, configured to hand over to the target base station when the reference signal received power of the target base station exceeds the reference signal received power of the source base station.

[0138] In this embodiment, after receiving the information of the target base station, the terminal continuously monitors the reference signal received power (RSRP) of the source base station and the RSRP of the target base station. When the RSRP from the target base station exceeds the RSRP of the source base station, the terminal immediately performs a cell handover, establishes a channel connection with the target base station, and releases the channel resources with the source base station.

[0139] An embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the cell handover method described above are implemented.

[0140] An embodiment of the present invention also provides a computer program product, including computer instructions, and when the computer instructions are executed by a processor, the steps of the cell handover method described above are implemented.

[0141] In the method embodiments of the present invention, the sequence numbers of the steps do not limit the order of the steps. For those of ordinary skill in the art, without creative efforts, the changes in the order of the steps are also within the protection scope of the present invention.

[0142] It should be noted that in this text, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or elements inherent to such a process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including that element. In addition, it should be pointed out that the methods and devices in the embodiments of the present application are not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the reverse order according to the functions involved. For example, the described method may be performed in a different order than described, and various steps may be added, omitted or combined. Additionally, the features described with reference to certain examples may be combined in other examples.

[0143] Through the description of the above embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of computer software products plus the necessary general hardware platforms, and of course, can also be implemented by hardware. The computer software products are stored in storage media (such as ROM, RAM, magnetic disks, optical disks, etc.), and the computer software products include several instructions for causing a terminal or a network-side device to execute the methods described in the various embodiments of the present application.

[0144] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Those of ordinary skill in the art, under the inspiration of the present application, without departing from the purpose of the present application and the scope protected by the claims, can also make many forms of embodiments, and these embodiments are all within the protection scope of the present application.

Claims

1. A cell handover method, characterized in that, Applied to the source base station, including: Sending a sensing signal, receiving the echo signal reflected by the terminal from the sensing signal, and determining the current position and moving speed of the terminal according to the echo signal; Determining the target base station of the terminal according to the current position and moving speed of the terminal, and sending the information of the target base station to the terminal; Determining whether the terminal enters the pre-switching range according to the current position, moving speed and handover delay of the terminal; After the terminal enters the pre-switching range, sending the user information of the terminal to the target base station.

2. The cell handover method according to claim 1, wherein: The sensing signal is carried by the primary synchronization signal PSS and / or the secondary synchronization signal SSS in the synchronization signal block SSB; or The sensing signal is carried by the demodulation reference signal DMRS in the SSB.

3. The cell handover method according to claim 1, wherein, The determining whether the terminal enters the pre-switching range according to the current position, moving speed and handover delay of the terminal includes: The distance d between the terminal and the target base station ue When the following formula is satisfied, it is determined that the terminal enters the pre - handover range: d ue -Δd ≤ d pre where d pre is a preset pre-switching threshold, and Δd is determined by the following formula: where v is the moving speed of the terminal, τ d is the overall delay, and τ is the handover delay.

4. The cell handover method according to any one of claims 1-3, characterized in that, The method further includes: Determining the target waveform used for the terminal communication according to the moving speed of the terminal, and sending the waveform information of the target waveform to the terminal.

5. The cell handover method according to claim 4, wherein: When the moving speed of the terminal is not greater than the preset speed threshold, the target waveform is the orthogonal frequency division multiplexing OFDM waveform; When the moving speed of the terminal is greater than the preset speed threshold, the target waveform is the orthogonal time-frequency-space OTFS waveform.

6. The cell handover method according to claim 5, wherein: The waveform information indicates that during the process of switching from the OFDM waveform to the OTFS waveform, the subcarrier spacing gradually increases; The waveform information indicates that during the process of switching from the OFDM waveform to the OTFS waveform, the subcarrier spacing gradually decreases.

7. A cell handover method, characterized in that, Applied to the terminal, including: Receiving the sensing signal sent by the source base station and reflecting the echo signal to the source base station; Receiving the information of the target base station sent by the source base station; Monitoring the reference signal receiving power of the source base station and the reference signal receiving power of the target base station; When the reference signal receiving power of the target base station exceeds the reference signal receiving power of the source base station, switching to the target base station.

8. A cell handover device, characterized in that, Applied to the source base station, including: A processing module, configured to send a sensing signal, receive the echo signal reflected by the terminal from the sensing signal, and determine the current position and moving speed of the terminal according to the echo signal; A determining module, configured to determine the target base station of the terminal according to the current position and moving speed of the terminal, and send the information of the target base station to the terminal; A judging module, configured to determine whether the terminal enters the pre-switching range according to the current position, moving speed and handover delay of the terminal; A sending module, configured to send the user information of the terminal to the target base station after the terminal enters the pre-switching range.

9. The cell handover device according to claim 8, wherein Further includes: A waveform switching module, configured to determine the target waveform used for the terminal communication according to the moving speed of the terminal, and send the waveform information of the target waveform to the terminal.

10. A cell handover device, characterized in that, Applied to the terminal, including: A transmission module, configured to receive the sensing signal sent by the source base station and reflect an echo signal back to the source base station; and receive the information of the target base station sent by the source base station; A monitoring module, configured to monitor the reference signal receiving power of the source base station and the reference signal receiving power of the target base station; A switching module, configured to switch to the target base station when the reference signal receiving power of the target base station exceeds the reference signal receiving power of the source base station.

11. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the cell switching method according to any one of claims 1 to 7 are implemented.

12. A computer program product, characterized in that, It includes computer instructions, and when the computer instructions are executed by a processor, the steps of the cell switching method according to any one of claims 1 to 7 are implemented.

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