NB-IOT base station terminal access method

Abstract

The invention relates to the technical field of Internet of Things communication, and discloses an NB-IOT base station terminal access method, which comprises the following steps: step 1, a base station receives an access request sent by a terminal, and the request carries an access reason value, a user identifier and user capability information; step 2, if the base station does not receive the core network response within the preset time, calculating the weight probability of the terminal in a control plane optimization mode based on the access reason value and the historical access mode data of the user identifier; and step 3, dynamically setting the time length of the timer according to the weight probability and the historical interaction time delay of the base station and the core network. According to the method, a base station side autonomous judgment strategy is adopted, and the terminal access mode of low core network dependence is judged through historical data statistics and dynamic weight probability calculation. Compared with a scheme completely depending on core network feedback in the prior art, the problem that the terminal access failure rate is high when the core network is delayed in response or fails is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of Internet of Things communication, and particularly to a method for NB-IoT base station terminal access. Background Art

[0002] With the rapid development of Internet of Things (IoT) technology, NB-IoT (Narrow Band Internet of Things), as an important technology for low-power wide-area network (LPWAN), is widely used in fields such as smart cities and industrial Internet of Things. In the NB-IoT network, terminal access is a key step to ensure device-network communication. However, in a high-latency and unstable network environment, such as satellite communication or deployment in remote areas, the success rate and efficiency of terminal access face severe challenges. In the prior art, the determination of the terminal access mode mainly relies on core network feedback, resulting in a significant increase in the access failure rate in high-latency or core network failure scenarios, and the user experience and system reliability are severely affected.

[0003] In the prior art, the determination of the terminal access mode (control plane optimization mode or user plane mode) is usually completed by the core network. The base station forwards the terminal access request to the core network and waits for the core network to return a control plane optimization access completion indication or a user plane context establishment request. The core network decides which access mode the terminal adopts according to the terminal's capabilities, service requirements, and network load. This solution performs well in scenarios where the core network responds in a timely manner and the link is stable, but it has obvious limitations in high-latency or core network failure scenarios.

[0004] The main problem of the prior art is the excessive dependence on core network feedback, resulting in a significant increase in the terminal access failure rate in high-latency or core network failure scenarios. For example, in a satellite communication scenario, due to the large latency of the space-ground link and the fast moving speed of the satellite, the terminal may have left the base station coverage area before the core network responds, resulting in access failure. In addition, when the core network load is too high or the link is unstable, the base station cannot obtain feedback in a timely manner, further exacerbating the access failure problem. The present invention solves the access failure problem caused by excessive dependence on the core network in the prior art through an autonomous decision-making strategy on the base station side, and significantly improves the success rate of terminal access and system reliability. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a method for NB-IoT base station terminal access, which solves the problem of high access failure rate of NB-IoT terminals in high-latency or core network failure scenarios.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for NB-IoT base station terminal access, comprising the following steps:

[0007] Step 1: The base station receives an access request sent by the terminal, and the request carries an access reason value, a user identifier, and user capability information.

[0008] Step 2: If the base station does not receive a core network response within a preset time, based on the historical access mode data of the access reason value and the user identifier, calculate the weight probability that the terminal is in the control plane optimization mode.

[0009] Step 3: Dynamically set the timer duration according to the weight probability and the historical interaction delay between the base station and the core network.

[0010] Step 4: If a core network response is not received before the timer times out, determine that the terminal completes the access process in the control plane optimization mode.

[0011] Preferably, the calculation of the weight probability includes:

[0012] Obtain the historical control plane mode probability corresponding to the access reason value.

[0013] Obtain the historical control plane mode probability corresponding to the user identifier.

[0014] Perform weighted summation of the historical control plane mode probability and a preset weight coefficient to obtain a comprehensive weight probability value.

[0015] Preferably, the update method of the historical control plane mode probability is:

[0016] For each access reason value, count the proportion of the number of successful accesses in the control plane mode to the total number of accesses within a preset time window.

[0017] For each user identifier, update the historical probability value based on its most recent access mode using the exponential smoothing method.

[0018] Preferably, the logic for dynamically setting the timer duration includes:

[0019] According to the maximum delay from the initial UE message to the core network response, the maximum response delay for a single message interaction, and the weight probability, shorten the waiting time for the high-probability control plane mode.

[0020] Preferably, the determination logic for the user capability information is:

[0021] If the terminal does not report the user plane optimization support field or the PDN attachment capability field, directly and forcibly determine it as the control plane optimization mode.

[0022] Preferably, the calculation formula for the timer duration is:

[0023]

[0024] Where:

[0025] T duration represents the maximum response delay for a single message interaction between the base station and the core network;

[0026] T idmax represents the maximum delay from when the base station sends the initial UE message until it receives a response from the core network;

[0027] P represents the weight probability;

[0028] P th is a preset determination threshold.

[0029] Preferably, after the determination terminal completes the access process according to the control plane optimization mode, it further includes:

[0030] Releasing the terminal radio resources, recording the access log, and updating the historical control plane mode probability of the user identifier.

[0031] Preferably, the core network response includes at least one of the following messages:

[0032] Control plane optimization access completion indication message, used to notify the base station that the terminal access is completed;

[0033] User plane context establishment request message, used to trigger the user plane bearer establishment process.

[0034] Preferably, the method further includes an exception handling logic:

[0035] If the number of consecutive non-responses from the core network exceeds the preset threshold, trigger an alarm and switch to a backup core network node;

[0036] Locally cache the unconfirmed access requests and resend them to the core network at a preset period.

[0037] The present invention provides a method for NB-IOT base station terminal access. It has the following beneficial effects:

[0038] 1. The present invention adopts an autonomous decision-making strategy on the base station side. Through historical data statistics and dynamic weight probability calculation, it realizes the determination of the terminal access mode with low core network dependence. Compared with the existing technology that completely relies on the core network feedback, it solves the problem of high terminal access failure rate when the core network has response delays or failures.

[0039] 2. The present invention realizes the adaptive adjustment of the timer duration through a dynamic timer formula, combined with historical delay statistics and weight probability. Compared with the existing technology that designs a fixed-duration timer, it solves the problems of resource waste or access timeout caused by network jitter.

[0040] 3. The present invention adopts a user identification history library and the exponential smoothing method to achieve a quick reference determination of the terminal access mode. Compared with the solution in the prior art that requires recalculation for each access, it solves the problem of low judgment efficiency. Brief Description of the Drawings

[0041] Figure 1 It is a schematic flowchart of the method of the present invention. Detailed Embodiments

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] Please refer to the attached Figure 1 , the embodiment of the present invention provides a method for NB-IOT base station terminal access, including:

[0044] By optimizing the base station side's independent decision-making mechanism and the core network cooperation process, the problem of delayed determination of the terminal access mode in high-latency scenarios is solved. The system architecture includes a terminal, a base station, and a core network. The interaction process covers access request processing, historical data retrieval, dynamic timer management, and exception recovery to ensure quick completion of terminal access. In this embodiment, the base station realizes the access mode determination with low core network dependence through multi-dimensional data fusion and dynamic formula adjustment, taking into account both efficiency and reliability.

[0045] The independent decision-making strategy is one of the core modules of the present invention, which is used to quickly determine the terminal access mode through multi-dimensional data fusion and dynamic calculation when the core network responds abnormally. This strategy is based on historical data statistics and real-time information analysis, and combines the cause value probability, user identification history, and user ability fields to achieve efficient judgment. In this embodiment, the independent decision-making strategy ensures the accuracy and timeliness of the judgment result through a sliding window mechanism, the exponential smoothing method, and a weight probability formula, and dynamically adjusts the timer duration to adapt to different network scenarios.

[0046] In this embodiment, the trigger condition of the independent decision-making strategy is that the core network does not respond within the preset time.

[0047] Generally, after the base station sends an initial UE message to the core network, it starts a response waiting timer (default 500ms). If no feedback from the core network is received after the timeout, the independent decision-making strategy is started. As an option, the preset time can be dynamically adjusted according to the network deployment scenario. For example, it is set to 1000ms in the satellite scenario.

[0048] In some embodiments, the base station retrieves the historical control plane mode probability P corresponding to the current access reason value from the local reason value statistics library. cn The reason value statistics library is maintained through a sliding window mechanism. The window size is set to 1000 accesses, and the probability update formula is:

[0049]

[0050] Where the number of successful control plane mode accesses is the number of times the terminal has successfully accessed in the control plane mode under this reason value within the statistical window, and the total number of accesses is the total number of requests for this reason value.

[0051] If the current access reason value is mo-Data, and historical statistics show that 80 out of 100 accesses are in the control plane mode, then P c1 = 0.8.

[0052] At the same time, the base station queries the user identification history library to obtain the historical control plane mode probability P corresponding to the user identification i The user identification history library is stored using a hash table. The key is the user identification, and the value is the probability value updated by the exponential smoothing method. The update formula is:

[0053]

[0054] Where α is the smoothing coefficient, defaulting to 0.9;

[0055] δ mode is the mode indication value, taking 1 if this access is in the control plane mode, otherwise taking 0.

[0056] If the historical probability P of the user identification S-TMSI-001 i = 0.6, and this access is in the control plane mode, then the updated probability is:

[0057]

[0058] In this embodiment, the base station calculates the weight probability P based on the above P cn and P i The formula is:

[0059]

[0060] Where,

[0061] N: The total number of categories of access reason values (such as the 6 reason values defined by the protocol);

[0062] δ(C n ): Indicator function, taking 1 when the current access reason value is the nth category (C n ), otherwise taking 0;

[0063] F c : Cause value weight coefficient, default set to 1, configurable from 0.5 to 2.0;

[0064] F i : User identification weight coefficient, default set to 1, configurable from 0.5 to 2.0.

[0065] In some embodiments, if the current access cause value is mo-Data (C1), and P c1 = 0.8, P i = 0.6, F c = F i = 1, then the weight probability calculation is:

[0066]

[0067] In this embodiment, the base station determines the access mode according to the weight probability PP and the preset threshold P tn . Generally, if P > P tn , it is determined as the control plane optimization mode; otherwise, it is determined as the user plane mode.

[0068] Specifically, if the terminal does not carry the user plane optimization support field or the PDN attachment capability field, it is directly and forcibly determined as the control plane optimization mode. The base station parses the terminal capability information field to quickly skip complex calculations and improve the decision-making efficiency.

[0069] The dynamic timer design is an important technical module of the present invention, which is used to ensure the rapid completion of the terminal access process in case of core network response delay or abnormality. This module dynamically adjusts the timer duration by combining historical delay statistics and the weight probability calculation result, avoiding access failures or resource waste caused by a fixed duration. In this embodiment, the timer duration is dynamically calculated through a formula based on the maximum delay from the initial UE message to the core network response, the maximum response delay of a single message interaction, and the weight probability, to adapt to the delay requirements of different network scenarios.

[0070] In this embodiment, the starting condition of the dynamic timer is after the base station sends the initial UE message.

[0071] While forwarding the terminal access request to the core network, the base station starts the dynamic timer. The initial duration of the timer can be preset according to the network deployment scenario. For example, it is set to 500 ms in an urban environment and 1000 ms in a satellite scenario.

[0072] The formula for calculating the timer duration is:

[0073]

[0074] Among them,

[0075] Tsdmax : The maximum response delay for a single message interaction between the base station and the core network, which is obtained by taking the maximum value from the historical data of the most recent 30 days;

[0076] T idmax : The maximum delay from the sending of the initial UE message to receiving the core network response, which is obtained by taking the maximum value from the historical data of the most recent 30 days;

[0077] P th : The determination threshold, which is default set to 0.7 and can be configured from 0.5 to 0.9.

[0078] For example, the formula shortens the waiting time in the high-probability control plane mode by dynamically adjusting the timer duration, improving the access efficiency. When T sdmax = 500ms, T idmax = 1000ms, and P th = 0.8, the timer duration is calculated as:

[0079]

[0080] In this embodiment, after the timer times out, the base station performs the forced access mode determination.

[0081] In this embodiment, the logic for dynamically adjusting the timer duration includes:

[0082] The timer duration shortens as the weighted probability P increases. When P approaches the determination threshold P th , the timer duration significantly decreases to accelerate the determination speed of the high-probability control plane mode. The correction term in the formula is used to dynamically adjust the waiting time to ensure that the timer duration matches the network state.

[0083] If the core network response is not received before the timer times out, the base station defaults that the terminal completes access in the control plane optimization mode, releases the radio resources and records the log. At the same time, the probability value in the user identification history library is updated to reflect the result of this determination. After the timer times out, the base station sends an alarm notification to the operation and maintenance system, indicating an abnormal core network response.

[0084] The statistical parameters T sdmax and T idmax are dynamically updated through historical data.

[0085] The base station statistically calculates the message interaction delay of the most recent 30 days at zero o'clock every day and takes the maximum value as T sdmax and T idmax . The statistical period can be dynamically adjusted according to the network load. For example, it is shortened to 7 days in a high-load scenario.

[0086] In some embodiments, the base station dynamically adjusts P thFor example, if the recent access success rate is lower than a preset value (such as 90%), then reduce P th to 0.6 to increase the determination probability of the control plane mode. The adjustment logic is implemented through a machine learning model and optimized by combining multi-dimensional data such as network load and terminal type.

[0087] The core network coordination and exception handling module is an important part of the present invention, which is used to ensure that the base station can still efficiently complete the terminal access process when the core network responds abnormally or there is a link failure. Through message format specifications, exception detection mechanisms and recovery strategies, this module guarantees the reliability of the system in a high-latency and unstable network environment. In this embodiment, the core network coordination mechanism includes message interactions for control plane optimized access completion indication and user plane context establishment request, and the exception handling mechanism covers core network fault detection, backup node switching and request retransmission logic to ensure service continuity in extreme scenarios.

[0088] In this embodiment, the format of the core network response message follows the JSON protocol and includes fields such as terminal identification, access mode type and timestamp. The message types returned by the core network include control plane optimized access completion indication and user plane context establishment request. The message format can be extended to support more fields, such as quality of service parameters.

[0089] In this embodiment, the base station determines the subsequent processing logic based on the type of the core network response message. If it receives a CP_COMPLETE message, the base station confirms that the terminal has completed access in the control plane optimized mode, releases the radio resources and records the log. If it receives a UP_SETUP message, the base station triggers the user plane bearer establishment process and allocates data radio resources. The base station parses the QoS field in the message and dynamically adjusts the resource allocation strategy.

[0090] In this embodiment, the core of the exception handling mechanism is core network fault detection and recovery.

[0091] The base station judges the core network status by the number of consecutive unresponses. As an option, the detection threshold is set to 3 times, that is, if the core network response is not received continuously 3 times, it is determined that the core network has failed. The base station maintains an exception counter (failure_count), and the counter is incremented by 1 each time there is an unresponse and cleared after receiving a response.

[0092] In this embodiment, the recovery strategy after core network failure includes backup node switching and request retransmission.

[0093] If the failure_count exceeds a preset threshold (e.g., 3 times), the base station triggers an alarm and switches to the backup core network node. The IP address of the backup node is preset through a configuration file, such as 10.0.0.2. The base station monitors the status of the backup node through a heartbeat detection mechanism (e.g., sending PING messages every 10 seconds) to ensure its availability.

[0094] In this embodiment, unacknowledged access requests are cached in a local queue and retried at a preset period. The base station maintains a request cache queue (request_queue) with a maximum capacity of 10 requests. The retry interval is set to 30 seconds each time, and the maximum number of retries is 3 times. The retry interval can be dynamically adjusted according to the network load, for example, shortened to 15 seconds in a high-load scenario.

[0095] In this embodiment, the exception handling mechanism also includes log recording and alarm notification.

[0096] After each core network failure or request retry failure, the base station records detailed logs, including information such as the failure time, terminal identifier, and number of retries. The base station sends an alarm notification to the operation and maintenance system through the SNMP protocol to indicate that the core network status is abnormal.

[0097] Embodiment 1: Probability Statistics Based on Access Cause Values

[0098] Scenario description: The terminal initiates an access request due to different access cause values (such as mo-Data, mt-Access), and the base station makes a mode determination based on historical statistical data.

[0099] Data collection:

[0100] The base station records each access cause value and the final mode. For example, if mo-Data is in the control plane mode 80 times out of 100 accesses, then P c1 = 0.8.

[0101] Probability update:

[0102] Adopt a sliding window mechanism, set the window size to 1000 accesses, and the probability update formula is:

[0103]

[0104] Decision logic:

[0105] If the current access cause value is mo-Data and P c1 = 0.8, then the weighted probability P is calculated as:

[0106]

[0107] If P > P th= 0.7, it is determined as the control plane mode.

[0108] Through historical data statistics, improve the accuracy of access mode determination and reduce the dependence on the core network.

[0109] Example 2:

[0110] Scenario description: The terminal accesses multiple times under a fixed base station, and the base station makes a mode determination based on the historical data of the user identifier (such as S-TMSI).

[0111] Data storage:

[0112] The base station uses a hash table to store the user identifier and its historical control plane mode probability P i .

[0113] Probability update:

[0114] After each access, update P according to the exponential smoothing method i :

[0115]

[0116] If the historical probability P of the user identifier S-TMSI-001 i = 0.6, and the current access is in the control plane mode, then the updated probability is:

[0117]

[0118] Decision logic:

[0119] If P i = 0.64, and the access reason value probability P cn = 0.8, then the weighted probability P is calculated as:

[0120]

[0121] If P > P th = 0.7, it is determined as the control plane mode.

[0122] Through the historical data of the user identifier, improve the decision-making efficiency for multiple accesses of the same terminal.

[0123] Example 3:

[0124] Scenario description: The base station dynamically adjusts the timer duration according to the historical delay statistics data to adapt to different network scenarios.

[0125] Delay statistics:

[0126] The base station statistics the message interaction delay in the recent 30 days and takes the maximum value as T sdmax and T idmax . For example, Tsdmax = 500 ms, T idmax = 1000 ms.

[0127] Timer calculation:

[0128] If the weight probability P = 0.8, the timer duration calculation is:

[0129]

[0130] Timeout handling:

[0131] If no response from the core network is received before the timer times out, it is forcibly determined to be in the control plane mode, resources are released, and a log is recorded.

[0132] By dynamically adjusting the timer duration, the access failure rate in high-latency scenarios is reduced.

[0133] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for NB-IOT base station terminal access, characterized in that, It includes the following steps: Step 1: The base station receives an access request sent by the terminal, where the request carries an access reason value, a user identifier, and user capability information; Step 2: If the base station does not receive a core network response within a preset time, based on the historical access mode data of the access reason value and the user identifier, calculate the weight probability that the terminal is in the control plane optimization mode; Step 3: Dynamically set the timer duration according to the weight probability and the historical interaction delay between the base station and the core network; Step 4: If a core network response is not received before the timer times out, determine that the terminal completes the access process in the control plane optimization mode.

2. The method for NB-IOT base station terminal access according to claim 1, wherein The calculation of the weight probability includes: Obtain the historical control plane mode probability corresponding to the access reason value; Obtain the historical control plane mode probability corresponding to the user identifier; Perform weighted summation of the historical control plane mode probability and a preset weight coefficient to obtain a comprehensive weight probability value.

3. A method for NB-IoT base station terminal access according to claim 1, characterized in that, The update method of the historical control plane mode probability is: For each access reason value, count the proportion of the number of successful accesses in the control plane mode to the total number of accesses within a preset time window; For each user identifier, update the historical probability value based on its most recent access mode using the exponential smoothing method.

4. A method for NB-IoT base station terminal access according to claim 1, characterized in that The logic for dynamically setting the timer duration includes: According to the maximum delay from the initial UE message to the core network response, the maximum response delay for a single message interaction, and the weight probability, shorten the waiting time for the high-probability control plane mode.

5. A method for NB-IoT base station terminal access according to claim 1, characterized in that, The determination logic of the user capability information is: If the terminal does not report a user plane optimization support field or a PDN attachment capability field, directly and forcibly determine it as the control plane optimization mode.

6. The method for NB-IOT base station terminal access according to claim 1, wherein The management of the historical access mode data of the user identifier includes: Store the user identifier and its corresponding control plane mode probability in the local hash table of the base station; If there is no new access request for the user identifier within a preset time, automatically delete its historical data.

7. A method for NB-IoT base station terminal access according to claim 1, characterized in that The calculation formula for the timer duration is: Where: T duration Indicates the maximum response delay for a single message interaction between the base station and the core network; T idmax Indicates the maximum time delay from when the base station sends the initial UE message until it receives the core network response; P represents the weight probability; P th is a preset determination threshold value.

8. A method for NB-IoT base station terminal access according to claim 1, characterized in that After determining that the terminal completes the access process in the control plane optimization mode, it further includes: Release the radio resources of the terminal, record the access log, and update the historical control plane mode probability of the user identifier.

9. A method for NB-IoT base station terminal access according to claim 1, characterized in that The core network response includes at least one of the following messages: A control plane optimization access completion indication message for notifying the base station that the terminal access is completed; A user plane context establishment request message for triggering the user plane bearer establishment process.

10. The method for NB-IOT base station terminal access according to claim 1, characterized in that The method further includes an exception handling logic: If the number of consecutive non-responses from the core network exceeds a preset threshold, trigger an alarm and switch to a backup core network node; Locally cache the unconfirmed access requests and resend them to the core network at a preset period.

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