A fast search method for NB-IoT narrowband Internet of Things

Abstract

The present invention relates to the technical field of data processing, and particularly relates to a fast search method for NB-IoT narrowband Internet of Things. The method includes: acquiring real-time wireless frame signals and historical wireless frame signals, performing signal co-variance detection based on the real-time wireless frame signals and the historical wireless frame signals, and calculating the connection strength of the m-th terminal device in the n-th cell currently and the connection strength in R cells; calculating connection priorities based on the connection strengths of R + 1 cells, determining whether to perform cell reselection based on the connection priorities. If cell reselection is to be performed, calculate the connection priorities of the m-th terminal device in the remaining cells, and obtain the decision degrees of the remaining cells when performing cell reselection; perform fast search on the cells by sorting the decision degrees from high to low, that is, the determination is more accurate when performing cell reselection, and the situation of communication fluctuations and instability caused by connecting to an inadaptable cell is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and particularly to a fast search method for NB-IoT (Narrow Band Internet of Things). Background Art

[0002] NB-IoT (narrow band-internet of things) is an emerging technology applicable to various intelligent sensors and devices. By optimizing the network structure, it enables devices to achieve long-distance data transmission while maintaining low power consumption. NB-IoT cell fast search refers to the process by which a terminal device (UE) searches for and connects to an NB-IoT network after power-on or during movement.

[0003] In practical application scenarios, the core objective of cell fast search is to accurately identify and determine the cell ID where the user equipment is currently located. NB-IoT defines narrowband primary synchronization signals and narrowband secondary synchronization signals for fast search. Traditional cell ID identification methods usually involve performing cross-correlation detection between all locally stored narrowband secondary synchronization signal sequences and the sequence to be detected, and determining the corresponding cell ID by detecting the cross-correlation peak. However, in real-time cell search scenarios, since some devices move continuously as the usage location changes, in order to maintain a stable network connection and communication quality, the device needs to perform fast and accurate switching between multiple cells. However, in urban environments, there are often a large number of cells with overlapping signal coverage. The device needs to accurately identify and select the best cell for connection. If the device makes an inaccurate determination during cell reselection or selects an inappropriate corresponding cell, it may cause the device to connect to an incompatible cell, thereby causing communication fluctuations and instability. Summary of the Invention

[0004] In order to solve the technical problem that the traditional cell ID identification method cannot accurately perform cell reselection, resulting in the device connecting to an incompatible cell, causing communication fluctuations and instability, the purpose of the present invention is to provide a fast search method for NB-IoT narrowband Internet of Things. The specific technical solution adopted is as follows:

[0005] Obtain real-time radio frame signals;

[0006] Obtain a terminal device, define that the mth terminal device is connected to the nth cell. If the nth cell and R cells have overlapping signals, obtain historical radio frame signals based on a total of R + 1 cells including the nth cell and the R cells, perform signal co-variation detection according to the real-time radio frame signals and the historical radio frame signals, and calculate the connection strength of the mth terminal device in the nth cell currently and the connection strength in the R cells;

[0007] Calculate the connection priority based on the connection strengths of R + 1 cells, determine whether to perform cell reselection based on the connection priority, and if so, generate an instruction and send it to the corresponding m-th terminal device for cell reselection;

[0008] Calculate the connection priority of the m-th terminal device in the remaining cells and obtain the decision degree of the remaining cells when performing cell reselection;

[0009] Quickly search for cells based on sorting the decision degrees from high to low.

[0010] Furthermore, obtain the real-time radio frame signal, including the following steps:

[0011] Obtain an NB-IoT device, use the NB-IoT device to receive the radio frequency signal of the base station through an antenna. The downlink signal sampling rate of the NB-IoT device is 1.92 MHz, and 100 radio frames are transmitted per second.

[0012] Furthermore, perform signal co-variation detection based on the real-time radio frame signal and the historical radio frame signal, including the following steps:

[0013] The historical radio frame signal generates multiple connection intervals according to the time sequence. Calculate the position characteristics of the signal strength corresponding to the real-time radio frame signal of the m-th terminal device in the connection intervals of the historical radio frame signal, and obtain the connection strength of the current terminal device in each cell based on the position characteristics.

[0014] Furthermore, the connection interval is all radio frame signals between the initial connection success and the connection interruption.

[0015] Furthermore, calculate the connection strength of the m-th terminal device currently in the n-th cell and the connection strengths in R cells. The corresponding calculation formula is:

[0016]

[0017] where θ m,r represents the connection strength of the m-th terminal device currently in the r-th connected cell; exp() represents the exponential function with the natural constant as the base; I represents the number of historical radio frame signal connection intervals of the m-th terminal device in the r-th connected cell; T m,r(i) represents the position of the current radio frame signal of the m-th terminal device in the i-th radio frame signal connection interval of the r-th connected cell; T r(i) represents the interval length of the i-th radio frame signal connection interval of the r-th connected cell of the current radio frame signal of the m-th terminal device, and is represented by the difference in the time sequence positions corresponding to the radio frame signals within the connection interval.

[0018] Further, when r = 0, it indicates that the m-th terminal device is connected to the current n-th cell.

[0019] Further, the connection priority is calculated based on the connection strengths of R + 1 cells, and the corresponding calculation formula is:

[0020]

[0021] where α m,r represents the connection priority of the m-th terminal device in the current r-th cell; θ m,r represents the connection strength of the m-th terminal device in the current r-th connected cell; represents the average value of the connection strengths in all wireless frame signal connection intervals of the m-th terminal device in the r-th cell; R represents the number of overlapping cells of the current r-th cell connected by the m-th terminal device; represents the sum of the average values of the wireless frame connection strengths of the m-th terminal device and the R + 1 historically connected cells.

[0022] Further, when k = 0, it represents the average value of the connection strengths in all historical wireless frame signal connection intervals of the current n-th cell connected by the m-th terminal device.

[0023] Further, it is determined whether to perform cell reselection based on the connection priority. If so, an instruction is generated and sent to the corresponding m-th terminal device for cell reselection, including the following steps:

[0024] Sort based on the connection priority to obtain a priority queue, and obtain the central position W0 of the priority queue and the position W of the m-th terminal device in the priority queue when it is currently in the n-th cell n , if W0 > W n , an instruction is generated and sent to the corresponding m-th terminal device for cell reselection; if W0 < W n , cell reselection is not required; if W0 = W n , based on the historical wireless frame signals, obtain the fluctuation situation. If it is stable, cell reselection is not required.

[0025] Further, calculate the connection priority of the m-th terminal device in the remaining cells and obtain the decision degree of the remaining cells during cell reselection, including the following steps:

[0026] Calculate the sliding correlation between the wireless frame signal of the m-th terminal device and the reference NSSS, calculate the connection priority of the m-th terminal device in the remaining cells, and obtain the decision degree of the remaining cells during cell reselection. The corresponding calculation formula is:

[0027]

[0028] Among them, ρ m,r represents the decision degree of the r-th cell when the m-th terminal device performs cell reselection; W r represents the position of the r-th connected cell of the m-th terminal device in the priority queue; R + 1 is the length of the priority queue; represents the sliding correlation between the current radio frame signal of the m-th terminal device and the reference NSSS signal of the r-th cell.

[0029] The present invention has the following beneficial effects: By calculating the signal connection strength change of the radio frame signal of the current terminal device in the connected cell and its corresponding overlapping coverage cell, and its position in the priority queue, the connection strength of the device in the current connected cell and the corresponding overlapping coverage cell is quantified. By determining the connection priority of the terminal device in each cell, it is determined whether the current terminal device needs to perform cell reselection. If so, calculate the decision degree of each cell during cell reselection, and finally determine the cell to be reselected by the current terminal device according to the decision degree from high to low, thereby realizing the process of quickly searching for the smallest cell, making the determination of cell reselection more accurate, and avoiding the situation of communication fluctuations and instability caused by connecting to an inappropriately matched cell. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 It is a flowchart of the steps of the fast search method for NB-IoT narrowband Internet of Things provided by an embodiment of the present invention;

[0032] Figure 2 It is an implementation flowchart of the fast search method for NB-IoT narrowband Internet of Things provided by an embodiment of the present invention;

[0033] Figure 3 It is a composition diagram of the radio frame signal of the fast search method for NB-IoT narrowband Internet of Things provided by an embodiment of the present invention. Detailed Embodiments

[0034] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following specifically describes, in conjunction with the accompanying drawings and preferred embodiments, a fast search method for an NB-IoT narrowband Internet of Things according to the present invention, including its specific implementation manner, structure, features, and effects, as follows. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0036] The following specifically describes the specific solution of a fast search method for an NB-IoT narrowband Internet of Things provided by the present invention in conjunction with the accompanying drawings.

[0037] The core of the traditional method for identifying cell IDs lies in performing cross-correlation detection on all local NSSS (narrowband secondary synchronization signals) sequences and the sequence to be detected. Generally speaking, this method is like looking for a specific friend in a crowd, where each possible target needs to be carefully compared. When the correlation degree reaches a certain peak value, the target that highly matches the sequence to be detected can be found. Adopting this method requires processing and analyzing a large amount of data. Since the device is usually moving continuously, the received data is constantly changing. To maintain a stable network connection and communication quality, it is necessary to continuously switch between cells, which requires a relatively high data analysis ability. If inaccurate data leads to inaccurate cell reselection determination, connecting to an inappropriate cell will cause unstable communication fluctuations. The first embodiment of the present invention provides a fast search method for an NB-IoT narrowband Internet of Things. This method aims to quantify the decision degrees of each cell during cell reselection by the connection strength of wireless frame signals and the change in the connection strength of historical wireless frame signals of overlapping coverage cells, and quickly search for cells to dynamically connect to them to maintain a stable network connection and communication quality. The specific steps in this method will be introduced in detail below.

[0038] Please refer to Figure 1 and Figure 2 , which respectively show the step flowchart and implementation flowchart of a fast search method for an NB-IoT narrowband Internet of Things provided by an embodiment of the present invention. The method includes:

[0039] Step S1: Obtain real-time wireless frame signals;

[0040] Step S2: Obtain the terminal device, define that the m-th terminal device is connected to the n-th cell. If the signals of the n-th cell and R cells overlap, based on the R + 1 cells including the n-th cell and the R cells, obtain the historical radio frame signals, perform signal co-variation detection according to the real-time radio frame signals and the historical radio frame signals, and calculate the connection strength of the m-th terminal device in the n-th cell currently and the connection strength in the R cells.

[0041] Step S3: Calculate the connection priority based on the connection strengths of the R + 1 cells, and determine whether to perform cell reselection based on the connection priority. If so, generate an instruction and send it to the corresponding m-th terminal device for cell reselection.

[0042] Step S4: Calculate the connection priority of the m-th terminal device in the remaining cells, and obtain the decision degree of the remaining cells when performing cell reselection.

[0043] Step S5: Perform a fast search for cells based on sorting the decision degrees from high to low.

[0044] It should be noted that NB-IoT (narrow band-internet of things) is an Internet of Things technology based on cellular networks. It is built on the existing cellular networks and only requires software upgrade of the existing LTE network to achieve low-cost and low-power Internet of Things connections. NB-IoT achieves low power consumption, enabling Internet of Things devices to operate stably for a long time without the need to frequently replace batteries. Moreover, NB-IoT has the characteristic of wide coverage and can cover remote areas that are difficult to reach by traditional wireless communications, providing a broader space for Internet of Things applications. It also supports large connections, that is, it can connect a large number of devices to meet the requirements of Internet of Things applications for the number of devices.

[0045] The terminal device refers to the device directly used by users, such as mobile phones, tablet computers, laptop computers, etc. These devices interact with the base station through the wireless communication network to achieve functions such as voice calls and data transmission; while the NB-IoT cell fast search refers to the process by which the terminal device (UE) searches for and connects to the NB-IoT network after power-on or during the movement process.

[0046] It can be explained that the NB-IoT cell fast search process generally includes the following steps:

[0047] First, after the terminal device is powered on, it will perform initialization operations, including reading configuration information, checking the battery power, etc. After completing the initialization, the device will start to execute the cell search process. During this process, the device continuously scans the surrounding available wireless signals to find the coverage area of the NB-IoT network.

[0048] Then, once the device detects the signal of the NB-IoT network, the device will attempt to synchronize with the network. The synchronization process includes time calibration and frequency calibration between the device and the network to ensure that both parties can accurately transmit data.

[0049] Secondly, the device will send a connection request to the network. This request contains the device's identity information and the required network resource information. After receiving the request, the NB-IoT network authenticates and authorizes the device to ensure that the device has legitimate access rights.

[0050] Finally, once the device passes authentication and obtains authorization, the network will send a connection response to the device to establish a stable communication connection. At this time, the device can transmit and receive data through the NB-IoT network.

[0051] In the process of wireless communication, signals are transmitted in frames. The wireless frame signal is the basic unit of information transmission in a wireless communication system, responsible for carrying data, control information, and various instructions. Among them, the real-time wireless frame signal refers to the wireless frame signal currently being transmitted, which carries real-time communication data and can ensure the timeliness and accuracy of communication; the historical wireless frame signal refers to the wireless frame signals that have been transmitted before. These signals are stored in a storage medium for subsequent analysis, processing, and optimization. They are characterized by a large amount of data and rich information, and can provide a large amount of historical data to understand the performance, fault conditions, and optimization directions of the wireless communication network, and can provide strong support for the improvement and development of the wireless communication network.

[0052] Signal overlap means that in a certain area, due to the overlapping of the signal coverage ranges of multiple wireless communication networks, the signals interfere with each other, affecting the communication quality; when the distance between cells is relatively close, signal overlap may occur. When the signals of two or more cells overlap, the mutual interference will make the signals unstable, the call quality deteriorate, and even disconnection may occur. Moreover, due to the mutual interference between signals, the instability of data transmission may occur, increasing the risk of data being stolen or tampered with.

[0053] In the NB-IoT network, cell reselection can ensure the stability of the network connection and the coherence of the user experience. Cell reselection refers to the process in which the terminal device switches from the current serving cell to another more suitable cell within the network coverage area according to certain strategies and conditions. Its purpose is to optimize the network connection quality and improve the data transmission rate and stability. That is, when the terminal device is moving, it may encounter problems such as a decrease in signal quality and an increase in interference. Through cell reselection, it can switch to a cell with better signal quality and less interference to ensure the stability and reliability of the network connection.

[0054] It can be noted that with the continuous development of wireless communication technology, in real-time cell search, more and more devices have mobility, such as smartphones, tablets, wearable devices, etc. During the movement of mobile devices, they will continuously enter and leave different communication cells. In order to ensure the continuity of communication, the device needs to continuously switch between cells. In order to complete the device switching process and maintain a stable communication speed and network quality, a fast search method for NB-IoT narrowband Internet of Things is proposed. First, by receiving wireless frame signals, real-time wireless communication information is obtained to provide basic data for subsequent search processes; information of the terminal device is obtained, and it is defined that the m-th terminal device is connected to the n-th cell. When the signals of the n-th cell overlap with those of R cells, based on the historical wireless frame signals of the cells, signal co-variation detection is performed to effectively distinguish the signals of different cells and provide a basis for calculating the connection strength; then, according to the connection strength of the n-th cell and the R + 1 cells including the R cells, the connection priority is calculated and sorted to provide a decision basis for whether to perform cell reselection. When cell reselection is required, corresponding instructions are generated and sent to the corresponding device; the connection priority of the m-th terminal device in the remaining cells is calculated to obtain the decision degree of the remaining cells during cell reselection, and the suitability of each cell as a handover target is evaluated through the decision degree; finally, through the sorting of the decision degrees, the process of fast search for the smallest cell is achieved, quickly locating to the most suitable handover target cell, thereby realizing fast and accurate cell handover. This setting not only improves the speed and accuracy of cell search but also reduces the handover failure rate, can enhance the stability and reliability of wireless communication, and meets the communication requirements of mobile devices during movement.

[0055] Preferably, obtaining the real-time wireless frame signal includes the following steps:

[0056] An NB-IoT device is obtained, and the NB-IoT device receives the radio frequency signal of the base station through an antenna. The downlink signal sampling rate of the NB-IoT device is 1.92 MHz, and 100 wireless frames are transmitted per second.

[0057] It is explained that the NB-IoT device is a low-power wide-area network communication technology in the field of the Internet of Things and is widely used in various intelligent devices, such as smart meters, smart parking, smart manhole covers, etc. These devices realize remote data collection and transmission through the NB-IoT network. Taking the smart city as an example, by deploying a large number of NB-IoT sensors, users can monitor the urban environmental quality, traffic conditions, and the operation status of public facilities in real time. This setting not only helps to improve the urban governance level but also provides a more convenient and comfortable living environment for citizens.

[0058] Obtain an NB-IoT device. The NB-IoT device receives the radio frequency signal from the base station through an antenna. The downlink signal sampling rate of the NB-IoT device is 1.92 MHz, and 100 wireless frames are transmitted per second.

[0059] It can be explained that the NB-IoT device receives the radio frequency signal from the base station through an antenna. Among them, the antenna is used for the reception and transmission of information. The radio frequency signal of the base station undergoes a complex modulation and demodulation process, and it has rich data and information for the NB-IoT device to read and process.

[0060] The sampling rate is 1.92 MHz, that is, the NB-IoT device can capture a large number of data samples in an extremely short time, ensuring the integrity and accuracy of the signal. The high sampling rate enables the NB-IoT device to maintain stable performance when processing high-speed data transmission and complex network environments; and the NB-IoT device can transmit 100 wireless frames per second, which has high transmission capacity. Each wireless frame can carry a certain amount of data. Through continuous wireless frame transmission, the NB-IoT device can achieve fast data transmission and real-time update.

[0061] Please refer to Figure 3 , which shows the composition diagram of the wireless frame signal of the fast search method for NB-IoT narrowband Internet of Things provided by an embodiment of the present invention. Specifically, the signal of each wireless frame is composed of 10 subframes. Among them, each subframe is composed of two time slots, and each time slot is composed of 7 OFDM signals. Each wireless frame signal includes a primary synchronization signal (NPSS) and a secondary synchronization signal (NSSS). Suppose a total of M cell wireless frame signals are obtained.

[0062] Make an explanation. OFDM (Orthogonal Frequency Division Multiplexing) signal, which divides the channel into several orthogonal subchannels, converts the high-speed data signal into parallel low-speed sub-data streams, and modulates them to be transmitted on each subchannel.

[0063] It can be explained that the subframe is the basic component of the wireless frame, carrying different data and instruction information, and jointly constituting the complete wireless frame. Each subframe is further divided into two time slots. The time slot is the basic time unit for the transmission of the wireless frame signal, and its length is determined according to the specific requirements of the communication system; in each time slot, usually 7 OFDM signals are included, effectively improving the spectrum utilization rate and anti-interference ability, and the OFDM signals are arranged and transmitted in a certain order within the time slot, realizing reliable data transmission; in addition, the wireless frame signal includes a primary synchronization signal (NPSS) and a secondary synchronization signal (NSSS). The primary synchronization signal is used for time offset and frequency offset estimation of the received signal, and the secondary synchronization signal is used for cell ID identification.

[0064] Preferably, signal co-variability detection is performed based on real-time wireless frame signals and historical wireless frame signals, including the following steps:

[0065] The historical wireless frame signals generate multiple connection intervals according to the time sequence. Calculate the position characteristics of the signal strength corresponding to the real-time wireless frame signal of the m-th terminal device in the connection intervals of the historical wireless frame signals, and obtain the connection strength of the current terminal device in each cell based on the position characteristics.

[0066] Preferably, the connection interval is all wireless frame signals between the initial connection success and connection interruption.

[0067] It should be noted that signal co-variability refers to a certain common change trend or pattern presented among multiple signals in terms of time or space. This may be due to the signal sources themselves having similar characteristics, or due to the signals being subject to similar interference or influence during propagation or processing. By detecting signal co-variability, the internal connections between signals can be revealed. In practical applications, signal co-variability detection has a wide range of application scenarios. For example, in the communication field, signal co-variability detection can be used to detect interference and noise between signals to optimize the performance of the communication system.

[0068] Signal strength refers to the strength of the existing wireless frame signal, that is, the strength of the wireless signal during the transmission process. The stronger the signal strength, the better the communication quality, and the higher the speed and stability of data transmission. On the contrary, if the signal strength is weak, the communication quality will be affected, resulting in problems such as slow data transmission speed and unstable connection. Connection strength refers to the stability and reliability of the connection established between the device and the cell, and is applied in fields such as wireless networks and Bluetooth connections. The higher the connection strength, the more stable the connection between the device and the cell, and the more reliable the data transmission. On the contrary, if the connection strength is weak, the connection between devices is more likely to be disconnected, resulting in data transmission termination or failure.

[0069] It can be explained that the historical wireless frame signals are a collection of wireless frame signals collected over a past period of time. They are generated according to the time sequence to form a series of continuous data, which reflects the changes in wireless signals at different time periods. Create connection intervals based on the historical wireless frame signals. The connection interval refers to the time period of the wireless frame signals experienced by the terminal device between the initial connection success and connection interruption. The signal changes within the time period reflect the connection status between the terminal device and the base station. Then calculate the position characteristics of the signal strength corresponding to the real-time wireless frame signal of the m-th terminal device in the connection intervals of the historical wireless frame signals, that is, find the corresponding position in the connection intervals of the historical wireless frame signals according to the timestamp of the real-time wireless frame signal, and obtain the connection strength of the current terminal device in each cell based on the position characteristics.

[0070] Specifically, in practical applications, calculate the position characteristics of the signal strength corresponding to the real-time wireless frame signal of the m-th terminal device among the historical connected wireless frame signals in these R + 1 cells; where the signal strength of the wireless frame in each connection is measured by the Received Signal Strength Indication (RSSI). RSSI is an indicator for measuring the received signal strength, which enables users to understand the impact during transmission. By measuring the RSSI value, the attenuation of the signal during transmission can be known to judge the quality of the signal. Analyze the RSSI data to obtain the variation law of the wireless frame signal strength. When the signal strength is low, it may be due to too far distance or the existence of obstacles. When the signal strength fluctuates greatly, it may be caused by multipath effects or interference signals.

[0071] For the r-th connected cell of the m-th device, there are multiple connection intervals for its historical wireless frame signals in chronological order; for each wireless frame signal connection interval, calculate the position characteristics of the current wireless frame signal in each wireless frame signal connection interval to determine the connection strength of the current wireless frame signal device in each cell.

[0072] Preferably, calculate the connection strength of the m-th terminal device currently in the n-th cell and the connection strengths in the R cells. The corresponding calculation formula is:

[0073]

[0074] where, θ m,r represents the connection strength of the m-th terminal device currently in the r-th connected cell; exp() represents the exponential function with the natural constant as the base; I represents the number of historical wireless frame signal connection intervals of the m-th terminal device in the r-th connected cell; T m,r(i) represents the position of the current wireless frame signal of the m-th terminal device in the i-th wireless frame signal connection interval in the r-th connected cell; T r(i) represents the interval length of the i-th wireless frame signal connection interval of the r-th connected cell of the current wireless frame signal of the m-th terminal device, and is represented by the difference in the chronological positions corresponding to the wireless frame signals within the connection interval.

[0075] It can be explained that T r(i) represents the interval length of the i-th wireless frame signal connection interval of the r-th connected cell of the current wireless frame signal of the m-th device; it is represented by the difference in the chronological positions corresponding to the interval wireless frame signals, reflecting the duration of the wireless frame signal within the connection interval to evaluate the connection state of the device. When The smaller the value, the higher the connection strength of the m-th device in the i-th radio frame signal connection interval of the r-th connected cell currently, that is, a smaller interval length difference indicates that the duration of the radio frame signal within the connection interval is more stable, reducing the possibility of continuous interruption or performance degradation caused by signal fluctuations.

[0076] Preferably, when r = 0, it indicates that the m-th terminal device is connected to the current n-th cell.

[0077] It is explained that when r = 0, a specific connection state has been achieved, that is, the m-th terminal device has successfully established a connection with the current n-th cell, and the terminal device has accessed the NB-IoT network provided by the cell and can start operations such as data transmission and voice calls.

[0078] Preferably, the connection priority is calculated based on the connection strengths of R + 1 cells, and the corresponding calculation formula is:

[0079]

[0080] where α m,r represents the connection priority of the m-th terminal device in the r-th cell currently; θ m,r represents the connection strength of the m-th terminal device in the r-th connected cell currently; represents the average value of the connection strengths of the m-th terminal device in all radio frame signal connection intervals of the r-th cell; R represents the number of overlapping cells of the r-th cell currently connected by the m-th terminal device; represents the sum of the average values of the radio frame connection strengths of the m-th terminal device and the R + 1 historically connected cells.

[0081] It is explained that the connection priority refers to classifying and sorting different connections according to the strength of the connection.

[0082] It can be explained that the larger the value, the greater the historical signal connection strength of the m-th device in the r-th cell compared to all R + 1 cells, reflecting that the m-th device is more inclined to select the r-th cell for communication at the current moment. At this time, the larger the value of θ m,r the larger the connection strength of the m-th device in the r-th connected cell currently, indicating that the communication quality of the terminal device in this cell is better and the reliability of data transmission is higher. Therefore, the larger the value of α m,r the higher the connection priority of the m-th device in the r-th cell currently.

[0083] Preferably, when k = 0, it represents the average value of the connection strengths of all historical radio frame signal connection intervals of the n-th cell currently connected by the m-th terminal device.

[0084] It is explained that when k = 0, it represents the average value of the connection strength in all historical wireless frame signal connection intervals of the nth cell currently connected by the mth terminal device, which reflects the average connection strength level of a terminal device within a cell, so as to understand the network coverage and signal quality of the area, and to recommend a more suitable network access scheme for users according to the connection strength performance of the terminal device in different cells, which can improve the user experience and communication efficiency.

[0085] Preferably, it is judged whether to perform cell reselection based on the connection priority. If so, an instruction is generated and sent to the corresponding mth terminal device for cell reselection, including the following steps:

[0086] Sort based on the connection priority to obtain a priority queue, and obtain the central position W0 of the priority queue and the position W of the mth terminal device in the priority queue when it is currently in the nth cell n , if W0 > W n , an instruction is generated and sent to the corresponding mth terminal device for cell reselection; if W0 < W n , cell reselection is not required; if W0 = W n , based on the historical wireless frame signals, obtain the fluctuation situation. If it is stable, cell reselection is not required.

[0087] It is explained that cell reselection ensures that the terminal device can select the optimal cell for communication to provide stable and high-quality communication services. First, sort the connection priorities according to the connection strength to obtain a priority queue to reflect the overall communication quality of each cell; then determine the central position of the priority queue and the position of the cell where the mth terminal device is currently located in the queue. Among them, the central position usually represents a preset judgment in the priority queue, and the position of the cell where the mth terminal device is currently located reflects the quality of its current communication environment. Compare W0 with W n If the priority of the central position is higher than the priority of the current position of the mth terminal device, cell reselection is required, and the cell reselection instruction is sent to the corresponding mth terminal device to notify it to perform cell reselection to switch to a new cell for communication, which can maintain a stable communication situation and network quality; on the contrary, if the priority of the central position is lower than the priority of the current position of the mth terminal device, it means that the current cell is already a better choice and cell reselection is not required. At this time, maintain the current communication state of the terminal device without performing any operations.

[0088] Specifically, calculate the signal strength of the radio frame signal of the nth cell where the mth terminal device is currently located, then calculate the position characteristics of the current radio frame signal in each radio frame signal connection interval to determine the connection strength of the current terminal device in each cell, and calculate the connection priority based on the connection strength to obtain a priority queue. Calculate the position of the nth cell where the mth terminal device is currently located in the priority queue. If its position is closer to the central position of the priority queue, it indicates that the connection strength of the mth terminal device in the rth cell is better. And the more forward the position is, it indicates that it is in the initial stage of connection. Due to the existence of the signal overlap area, the current connection accuracy is more unstable. On the contrary, the more backward the position is, it indicates that it is in the end stage of connection, and the greater the possibility that the current connection needs to be reconnected, that is, cell reselection is required.

[0089] As an alternative implementation, if W0 = W n , obtain the fluctuation situation based on the historical radio frame signal, that is, analyze the obtained historical radio frame signal to obtain its fluctuation situations such as signal quality and load. If the reaction trend of the fluctuation situation is stable and good, cell reselection is not required; on the contrary, if the historical radio frame signal indicates that the performance of this cell may decline in some periods, that is, the reaction trend fluctuates severely and unstably, then cell reselection is required.

[0090] Preferably, calculate the connection priority of the mth terminal device in the remaining cells and obtain the decision degree of the remaining cells during cell reselection, including the following steps:

[0091] Calculate the sliding correlation between the radio frame signal of the mth terminal device and the reference NSSS, calculate the connection priority of the mth terminal device in the remaining cells, and obtain the decision degree of the remaining cells during cell reselection. The corresponding calculation formula is:

[0092]

[0093] Among them, ρ m,r represents the decision degree of the rth cell when the mth terminal device performs cell reselection; W r represents the position of the rth connected cell of the mth terminal device in the priority queue; R + 1 is the length of the priority queue; represents the sliding correlation between the current radio frame signal of the mth terminal device and the reference NSSS signal of the rth cell.

[0094] It should be noted that the decision degree refers to a comprehensive index for evaluating and comparing the remaining cells during cell reselection, and it is an index used to measure the suitability of different cells for the connection of mobile devices.

[0095] Sliding correlation is used to describe the degree of correlation between two signals or data sequences under a sliding window, so as to reveal the dynamic relationship between them. Through the correlation within the sliding window, the local relationship between signals can be observed, which reflects the change trend at different time or space scales. The calculation of sliding correlation involves multiplying two signals point by point and taking the average, and this average is the correlation coefficient within the sliding window. When the correlation coefficient is close to 1, it indicates that the two signals are highly similar within this window; when the correlation coefficient is close to -1, it indicates an anti-correlation relationship within this window. Sliding correlation is usually applied in various fields. For example, in signal processing, it is often used to detect periodic components in signals or identify the association patterns between different signals; in financial market analysis, sliding correlation can help investors discover the relationship between stock prices and macroeconomic indicators to formulate more effective investment strategies.

[0096] Calculate the sliding correlation between the wireless frame signal of the m-th terminal device and the reference NSSS. NSSS is used to achieve synchronization and identification in a wireless communication system, and it has unique features that enable the receiving end to easily distinguish it from other signals. Preferably, in order to improve the accuracy and reliability of the calculation results, digital signal processing techniques can be used to filter and denoise the signals to reduce the impact of interference and noise on the calculation results.

[0097] By calculating the sliding correlation, data on the similarity between the wireless frame signal received by the terminal device and the reference NSSS is obtained. This data can not only help evaluate the synchronization performance of the signal, but also be used to identify the characteristics and sources of the signal. If the sliding correlation is high, it indicates that the signal received by the terminal device has a high similarity with the reference NSSS, and the signal transmission quality is good at this time. On the contrary, if the sliding correlation is low, it may indicate that the signal is interfered or the transmission quality is poor.

[0098] According to the connection priority of the m-th terminal device in the remaining cells, obtain the decision degree of each remaining cell during cell reselection. It represents the comprehensive evaluation result of the terminal device for each candidate cell during cell decision-making. When the terminal device is moving at high speed, it tends to select large cells with a wide coverage range and stable signals to ensure the continuity of communication.

[0099] It can be explained that The smaller the value, the higher the priority of the r-th connected cell of the m-th terminal device in the priority queue, that is, the r-th connected cell of the m-th terminal device is more forward in the priority queue, and the priority is also higher; The larger the value, the higher the matching degree between the received signal and the expected NSSS signal, that is, the better the synchronization of the NSSS signal of the device's target cell. Therefore, ρ m,rThe larger the value is, the higher the decision degree of the r-th cell during the cell reselection of the m-th device, indicating that the terminal device has a more positive comprehensive evaluation of this cell. At this time, this cell serves as the new connection target.

[0100] It is explained that in step S5, the cells are quickly searched based on the sorting from high to low of the decision degree. Sorting the decision degree from high to low enables the performance of the cells in dimensions such as signal strength and connection strength to be scored, and the scores are sorted in descending order, enabling the device to quickly find excellent-performing cells, saving a large amount of time and effort.

[0101] Specifically, due to changes in the network environment and user requirements, the m-th terminal device disconnects from the current cell. This step ensures that the device is not interfered by the signal of the current cell when searching for a new cell. Based on the decision degree sorted from high to low obtained above, the cell with the largest decision degree is selected for connection. Then the device updates its corresponding internal state, including updating the information of the currently connected cell, as well as relevant network parameters and configurations, to achieve fast cell search. At this time, the device communicates with the new cell and enjoys a more stable and efficient network service. This not only improves the utilization efficiency of network resources but also enables the user to maintain a stable network connection during movement, meeting the needs of various real-time communications and data transmissions, and providing a smoother and more convenient network experience for the user.

[0102] It can be understood that by calculating the change in the signal connection strength of the wireless frame signal of the current terminal device in the connected cell and its corresponding overlapping coverage cell's historical wireless frame signals, and its position in the priority queue, the connection strength of the device in the current connected cell and the corresponding overlapping coverage cell is quantified. Whether the current terminal device needs to perform cell reselection is determined by the connection priority of the terminal device in each cell. If necessary, the decision degree of each cell during cell reselection is calculated. Finally, the cells that the current terminal device needs to reselect are determined according to the sorting from high to low of the decision degree, thereby realizing the process of quickly searching for the smallest cell, making the determination of its cell reselection more accurate, and avoiding the situation of communication fluctuations and instability caused by connecting to an incompatible cell.

[0103] It should be noted that the above sequence of the embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be beneficial.

[0104] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key points of each embodiment are to illustrate the differences from other embodiments.

Claims

1. A fast search method for NB-IoT narrowband Internet of Things, characterized in that, The method includes: Obtain a real-time wireless frame signal; Obtain a terminal device, define that the m-th terminal device is connected to the n-th cell. If the signals of the n-th cell and R cells overlap, obtain a historical wireless frame signal based on a total of R + 1 cells including the n-th cell and the R cells, perform signal co-variation detection according to the real-time wireless frame signal and the historical wireless frame signal, and calculate the connection strength of the m-th terminal device in the n-th cell currently and the connection strengths in the R cells; Calculate a connection priority based on the connection strengths of the R + 1 cells, determine whether to perform cell reselection based on the connection priority. If so, generate an instruction and send it to the corresponding m-th terminal device for cell reselection; Calculate the connection priorities of the m-th terminal device in the remaining cells and obtain the decision degrees of the remaining cells during cell reselection; Perform a fast search for cells based on sorting the decision degrees from high to low; Performing signal co-variation detection according to the real-time wireless frame signal and the historical wireless frame signal includes the following steps: The historical wireless frame signal generates multiple connection intervals according to the time sequence. Calculate the position characteristics of the signal strength corresponding to the real-time wireless frame signal of the m-th terminal device in the connection intervals of the historical wireless frame signal, and obtain the connection strength of the current terminal device in each cell based on the position characteristics; Among them, calculating the connection strength of the m-th terminal device in the n-th cell currently and the connection strengths in the R cells, the corresponding calculation formula is: ； Among them, represents the connection strength of the m-th terminal device in the r-th connected cell currently; represents the exponential function with the natural constant as the base; represents the number of historical radio frame signal connection intervals of the m-th terminal device in the r-th connected cell; represents the position of the current radio frame signal of the m-th terminal device in the i-th radio frame signal connection interval in the r-th connected cell; represents the interval length of the i-th radio frame signal connection interval of the r-th connected cell of the current radio frame signal of the m-th terminal device, and is represented by the difference in the timing positions corresponding to the radio frame signals within the connection interval; Calculating the connection priority based on the connection strengths of the R + 1 cells, the corresponding calculation formula is: ； Among them, represents the connection priority of the m-th terminal device in the r-th cell currently; represents the connection strength of the m-th terminal device in the r-th connected cell currently; represents the average value of the connection strength in all radio frame signal connection intervals of the m-th terminal device in the r-th cell; represents the number of overlapping cells of the r-th cell currently connected by the m-th terminal device; represents the sum of the average values of the radio frame connection strengths of the m-th terminal device and the R + 1 historically connected cells.

2. The rapid search method for NB-IoT narrowband Internet of Things according to claim 1, wherein: Obtaining a real-time wireless frame signal includes the following steps: Obtain an NB-IoT device. The NB-IoT device receives the radio frequency signal of the base station through an antenna. The downlink signal sampling rate of the NB-IoT device is 1.92 MHz, and 100 wireless frames are transmitted per second.

3. The rapid search method for NB-IoT narrowband Internet of Things according to claim 1, characterized in that: The connection interval is all wireless frame signals between the initial connection success and the connection interruption.

4. The rapid search method for NB-IoT narrowband Internet of Things according to claim 1, wherein: When it indicates that the m-th terminal device is connected to the current n-th cell.

5. The fast search method for NB-IoT narrowband Internet of Things according to claim 1, characterized in that: When it represents the average connection strength in the connection intervals of all historical radio frames of the nth cell currently connected by the mth terminal device.

6. The rapid search method for NB-IoT narrowband Internet of Things according to claim 1, characterized in that: Determining whether to perform cell reselection based on the connection priority. If so, generate an instruction and send it to the corresponding m-th terminal device for cell reselection includes the following steps: Sort based on connection priority to obtain a priority queue, and obtain the central position of the priority queue and the position of the m-th terminal device in the priority queue when it is currently in the n-th cell , if , generate an instruction and send it to the corresponding m-th terminal device for cell reselection; if , no cell reselection is required; if , obtain the fluctuation situation based on the historical radio frame signals, and if it is stable, no cell reselection is required.

7. The fast search method for NB-IoT narrowband Internet of Things according to claim 1, characterized in that: Calculating the connection priorities of the m-th terminal device in the remaining cells and obtaining the decision degrees of the remaining cells during cell reselection includes the following steps: Calculate the sliding correlation between the wireless frame signal of the m-th terminal device and the reference NSSS, calculate the connection priorities of the m-th terminal device in the remaining cells, and obtain the decision degrees of the remaining cells during cell reselection. The corresponding calculation formula is: ； Among them, represents the decision degree of the r-th cell when the m-th terminal device performs cell reselection; represents the position of the r-th connected cell of the m-th terminal device in the priority queue; is the length of the priority queue; represents the sliding correlation between the current radio frame signal of the m-th terminal device and the reference NSSS signal of the r-th cell.

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