A communication link switching method for heterogeneous networks

Abstract

The present application relates to the field of smart grid technology, and in particular to a communication link switching method for heterogeneous networks. By constructing a network link quality weighted evaluation model for cellular mobile networks, narrowband Internet of Things and Wi-SUN networks, and monitoring and evaluating the communication link quality of different types of networks according to real-time link quality evaluation parameters and the network link quality weighted evaluation model, the quality status of the current communication link can be intelligently identified; and when the link quality of any network is lower than a preset threshold, the method can quickly trigger the switching action of the communication link, and switch the uplink communication link of the gateway from a network with poor quality to a network with better quality, which not only significantly improves the stability and reliability of the communication link, but also effectively avoids communication interruption or data loss caused by poor network quality, thereby optimizing the overall network communication performance and ensuring the continuity and reliability of data transmission.

Description

Technical Field

[0001] The present application relates to the field of smart grid technology, and in particular to a communication link switching method for a heterogeneous network. Background Art

[0002] With the rapid development of technologies such as sensor technology and wireless communication, the Internet of Things technology has been widely used in the power industry, especially in the AMI system in the smart grid, which uses a variety of wireless networks, such as wireless local area network (Wi-Fi), cellular mobile network (3G / 4G / 5G), narrowband Internet of Things (NB-IoT) and wireless local area network (Wi-SUN) and other different types of networks to meet the needs of equipment access and services. Due to the different underlying protocols of various wireless communication technologies, the AMI system needs to deploy and integrate multiple network interfaces and multi-mode gateways to achieve direct communication indirectly through protocol conversion and data forwarding. However, in the existing AMI network architecture, the uplink and downlink wireless communication modules of the gateway are usually fixed, and it is difficult to perceive link failures in time, which will affect the success rate and stability of business reading.

[0003] Current technical solutions mainly focus on evaluating and optimizing link quality. For example, a wireless link quality evaluation method disclosed in the patent application with publication number CN116133034A accurately evaluates the link quality between nodes by filtering and scoring the received signal strength indication information. However, these solutions are limited to evaluating the wireless link quality of each node in the local network environment, and lack flexibility and compatibility with different network environments. Therefore, when the gateway accesses other wireless communication areas, the communication link is often unstable. Summary of the invention

[0004] Based on this, it is necessary to provide a communication link switching method for a heterogeneous network to solve the problem of unstable communication links when the existing gateway accesses other wireless communication areas. The method includes:

[0005] Step S1, constructing a first network link quality weighted evaluation model and a second network link quality weighted evaluation model; the first network link quality weighted evaluation model is used to evaluate the link quality of a cellular mobile network or a narrowband Internet of Things, and the second network link quality weighted evaluation model is used to evaluate the link quality of a Wi-SUN network;

[0006] Step S2, obtaining a first network quality assessment result according to the first network link quality weighted assessment model and the first link quality assessment parameter; obtaining a second network quality assessment result according to the second network link quality weighted assessment model and the second link quality assessment parameter;

[0007] Step S3: when the first network quality evaluation result is less than a first preset evaluation threshold, the uplink communication link is switched from the cellular mobile network or the narrowband Internet of Things to the Wi-SUN network.

[0008] Step S4: when the second network quality evaluation result is less than a second preset evaluation threshold, the uplink communication link is switched from the Wi-SUN network to a cellular mobile network or a narrowband Internet of Things.

[0009] In one of the embodiments, the communication link switching method of a heterogeneous network further includes:

[0010] Step S5, obtaining a comprehensive network link quality evaluation result according to the first network quality evaluation result and the second network quality evaluation result;

[0011] Step S6: dynamically adjust the wireless link monitoring period according to the comprehensive network link quality evaluation result.

[0012] In one embodiment, the method for adjusting the wireless link monitoring period is as follows:

[0013]

[0014] In the formula, is the adjusted wireless link monitoring period, is the adjustment factor, To synthesize the network link quality assessment results, The monitoring period is set.

[0015] In one embodiment, the heterogeneous network includes an AMI main station and at least one Wi-SUN root router, each Wi-SUN root router is connected to the AMI main station, the uplink communication link of the Wi-SUN root router is a 4G cellular mobile network, and the downlink communication link is a Wi-SUN network; step S2 includes:

[0016] Step S201, the Wi-SUN root router periodically sends data packets to the AMI master station to test the PRR indicator;

[0017] Step S202: When the PRR indicator is lower than a preset PRR threshold, the Wi-SUN root router obtains a first link quality evaluation parameter, and obtains a first network quality evaluation result according to the first link quality evaluation parameter and a first network link quality weighted evaluation model;

[0018] Step S3 includes:

[0019] Step S301: When a first network quality evaluation result is lower than a first preset evaluation threshold, the Wi-SUN root router switches to a relay node, and switches an uplink communication link to a Wi-SUN network.

[0020] In one of the embodiments, the heterogeneous network includes an AMI master station, a Wi-SUN root router, and a Wi-SUN relay node, the Wi-SUN relay node is connected to the Wi-SUN root router, the Wi-SUN root router is connected to the AMI master station, and both the uplink and downlink communication links of the Wi-SUN relay node are Wi-SUN networks;

[0021] Step S2 includes:

[0022] Step S211, the Wi-SUN relay node periodically sends data packets to the AMI master station to test the PRR indicator;

[0023] Step S212: When the PRR indicator is lower than the preset PRR threshold, the Wi-SUN relay node obtains a second link quality evaluation parameter, and obtains a second network quality evaluation result according to the second link quality evaluation parameter and the second network link quality weighted evaluation model;

[0024] Step S3 includes:

[0025] Step S311: When the second network quality evaluation result is lower than the second preset evaluation threshold, the Wi-SUN relay node switches to a Wi-SUN root router, and switches the uplink communication link back to the cellular mobile network or the narrowband Internet of Things.

[0026] In one embodiment, the expression of the first network link quality weighted evaluation model is:

[0027]

[0028] In the formula, Indicates the link quality score of the cellular mobile network or narrowband IoT. is the normalized received signal strength, is the weight of the received signal strength, is the reference signal strength of the received signal after normalization, is the weight of the received signal reference signal strength, is the normalized signal to interference plus noise ratio, is the weight of the signal to interference plus noise ratio, is the normalized packet reception rate, is the weight of the packet receiving rate.

[0029] In one embodiment, the values ​​of the weights in the first network link quality weighted assessment model are as follows:

[0030] ;

[0031] ;

[0032] ;

[0033]

[0034] In the formula, is the received signal strength, is the reference signal strength of the received signal, is the signal to interference plus noise ratio, is the packet receiving rate.

[0035] In one embodiment, the expression of the second network link quality weighted evaluation model is:

[0036]

[0037] In the formula, Score the link quality of the Wi-SUN network. is the standardized link quality indicator, is the weight of the link quality indicator.

[0038] In one embodiment, the values ​​of the weights in the second network link quality weighted assessment model are as follows:

[0039] ;

[0040] ;

[0041]

[0042] In the formula, Indicates the link quality.

[0043] In one of the embodiments, the communication link switching method of a heterogeneous network further includes:

[0044] Step S7: dynamically adjust the first preset evaluation threshold and the second preset evaluation threshold according to the link quality before and after the switching.

[0045] The above-mentioned communication link switching method for heterogeneous networks constructs a network link quality weighted evaluation model for cellular mobile networks, narrowband Internet of Things and Wi-SUN networks, and monitors and evaluates the communication link quality of different types of networks according to real-time link quality evaluation parameters and the network link quality weighted evaluation model, so as to intelligently identify the quality status of the current communication link; and when the link quality of any network is lower than a preset threshold, the method can quickly trigger the switching action of the communication link, and switch the uplink communication link of the gateway from a network with poor quality to a network with better quality, which not only significantly improves the stability and reliability of the communication link, but also effectively avoids communication interruption or data loss caused by poor network quality, thereby optimizing the overall network communication performance and ensuring the continuity and reliability of data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of a flow chart of a method for switching communication links in a heterogeneous network in one embodiment;

[0047] Figure 2 A schematic diagram showing a comparison before and after switching of a communication link of a heterogeneous network in an embodiment;

[0048] Figure 3 A schematic diagram showing a comparison before and after switching of a communication link of a heterogeneous network in another embodiment;

[0049] Figure 4 It is a flowchart of a communication link switching method of a heterogeneous network in another embodiment. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0051] The communication link switching method for heterogeneous networks provided in this application can be applied to an AMI (Advanced Metering Infrastructure) system where multiple wireless networks coexist. The wireless networks include but are not limited to different types of networks such as wireless local area network (Wi-Fi), cellular mobile network (3G / 4G / 5G), narrowband Internet of Things (NB-IoT) and wireless local area network (Wi-SUN).

[0052] Example 1

[0053] like Figure 1 As shown, a communication link switching method for a heterogeneous network is provided, and the method is explained by applying it to a Wi-SUN gateway, which specifically includes the following steps:

[0054] Step S1: construct a first network link quality weighted evaluation model and a second network link quality weighted evaluation model. The first network link quality weighted evaluation model is used to evaluate the link quality of a cellular mobile network or a narrowband Internet of Things, and the second network link quality weighted evaluation model is used to evaluate the link quality of a Wi-SUN network.

[0055] Among them, link quality assessment is a key link to ensure the stability and reliability of wireless communication systems. For different types of networks, different indicators can be combined for comprehensive assessment. For example, for cellular mobile networks and narrowband Internet of Things, the following evaluation indicators are mainly considered:

[0056] (1) Evaluation indicators based on the hardware physical layer:

[0057] RSSI (Received Signal Strength Indicator): reflects the strength of the received signal. Generally, when RSSI is greater than -90dBm, it means the signal quality is good, and when it is less than -110dBm, it means the signal quality is poor.

[0058] RSRP (Received Signal Strength in Reference Point): Provides more accurate information about signal quality. Set thresholds as follows: RSRP greater than -85dBm indicates good signal coverage, RSRP between -95dBm and -85dBm is considered good, and RSRP below -105dBm is considered unusable.

[0059] SINR (Signal to Interference plus Noise Ratio): refers to the ratio of the strength of the received useful signal to the strength of the received interference signal (noise and interference), which is used to measure the clarity and availability of the signal. Generally speaking, when SINR is greater than 25dB, the signal quality is considered excellent, when SINR is between 14dB and 25dB, the signal quality is considered good, and when SINR is less than 3dB, the signal quality is considered poor.

[0060] (2) Evaluation indicators based on the software link layer:

[0061] PRR (Packet Reception Rate): used to evaluate the reliability of data transmission, usually between 0 and 1. When PRR is lower than 0.8, it means that the connection stability is poor. When PRR is lower than 0.2, it means that the network is unavailable. The calculation formula of PRR is shown in formula (1):

[0062] (1)

[0063] In the formula, Indicates all packets sent. Indicates a successfully received packet.

[0064] Specifically, the first network link quality weighted evaluation model may include one or more of the above evaluation indicators, and each evaluation indicator is assigned a corresponding weight. Preferably, the mathematical expression of the first network link quality weighted evaluation model is shown in formula (2):

[0065] (2)

[0066] In formula (2), Indicates the link quality score of the cellular mobile network or narrowband IoT. is the normalized received signal strength, is the weight of the received signal strength, is the reference signal strength of the received signal after normalization, is the weight of the received signal reference signal strength, is the normalized signal to interference plus noise ratio, is the weight of the signal to interference plus noise ratio, is the normalized packet reception rate, is the weight of the packet receiving rate.

[0067] In order to be able to , , and Indicators are compared and comprehensively analyzed. This embodiment converts the original value range of each indicator into a unified standard range, usually between 0 and 1. This conversion is based on the value range of each indicator itself, with the aim of eliminating the difficulty in comparing different indicators due to different dimensions or value ranges. Specific standardization methods may include linear transformation, Z-score standardization, min-max standardization, etc., which are not limited here. , , and All values ​​are standardized, so the quality of the communication link can be evaluated more accurately.

[0068] Furthermore, the values ​​of each weight can be dynamically adjusted according to the actual network environment to ensure the accuracy and effectiveness of the evaluation results. Preferably, the weight of each indicator in the first network link quality weighted evaluation model can be dynamically adjusted according to the relationship shown in equations (3)-(6):

[0069] (3)

[0070] (4)

[0071] (5)

[0072] (6)

[0073] For Wi-SUN networks, in addition to RSSI, RSRP and PRR indicators, the LQI (link quality indicator) indicator also needs to be considered. The value range of LQI is from 0 to 255, and the higher the value, the better the link quality. Generally, when LQI is greater than 150, it means that the signal quality is excellent, and when LQI is less than 100, it means that packet loss may occur occasionally. Similarly, the second network link quality weighted evaluation model may include one or more evaluation indicators of the above-mentioned Wi-SUN network, and each evaluation indicator is assigned a corresponding weight. Preferably, the mathematical expression of the second network link quality weighted evaluation model is shown in formula (7):

[0074] (7)

[0075] In the formula, Score the link quality of the Wi-SUN network. is the standardized link quality indicator, is the weight of the link quality indicator. Similarly, in order to more accurately evaluate the quality of the communication link, the evaluation indicators in formula (7) ( , and ) are all evaluation indicators that have been standardized according to their respective value ranges. Similarly, the values ​​of each weight in the second network link quality weighted evaluation model can be dynamically adjusted according to the actual network environment to ensure the accuracy and effectiveness of the evaluation results. Preferably, the weight of each indicator in the second network link quality weighted evaluation model can be dynamically adjusted according to the relationship shown in equations (8)-(10):

[0076] (8)

[0077] (9)

[0078] (10)

[0079] Step S2, obtaining a first network quality assessment result according to the first network link quality weighted assessment model and the first link quality assessment parameters; obtaining a second network quality assessment result according to the second network link quality weighted assessment model and the second link quality assessment parameters.

[0080] Among them, the first link quality evaluation parameter is an evaluation index included in the first network link quality weighted evaluation model. For example, when the first network link quality weighted evaluation model is as shown in formula (2), the first link quality evaluation parameter may include RSSI, RSRP, SINR and PRR. The second link quality evaluation parameter is an evaluation index included in the second network link quality weighted evaluation model. For example, when the second network link quality weighted evaluation model is as shown in formula (7), the second link quality evaluation parameter may include RSSI, LQI and PRR.

[0081] Specifically, after the Wi-SUN gateway obtains the first link quality evaluation parameter and the second link quality evaluation parameter from the link layer and the physical layer, the first link quality evaluation parameter is substituted into the first network link quality weighted evaluation model to obtain a first network quality evaluation result, which is the link quality score of the cellular mobile network or the narrowband Internet of Things at this time; the second link quality evaluation parameter is substituted into the second network link quality weighted evaluation model to obtain a second network quality evaluation result, which is the link quality score of the Wi-SUN network at this time.

[0082] Step S3: when the first network quality evaluation result is less than a first preset evaluation threshold, the uplink communication link is switched from the cellular mobile network or the narrowband Internet of Things to the Wi-SUN network.

[0083] Step S4: when the second network quality evaluation result is less than a second preset evaluation threshold, the uplink communication link is switched from the Wi-SUN network to a cellular mobile network or a narrowband Internet of Things.

[0084] Specifically, if the uplink communication link of the current Wi-SUN gateway is a cellular mobile network or a narrowband Internet of Things, when the Wi-SUN gateway detects that the first network quality evaluation result is less than the first preset evaluation threshold, the Wi-SUN gateway switches the uplink communication link from the current cellular mobile network or the narrowband Internet of Things to the Wi-SUN network. If the uplink communication link of the current Wi-SUN gateway is a Wi-SUN network, when the Wi-SUN gateway detects that the second network quality evaluation result is less than the second preset evaluation threshold, the Wi-SUN gateway switches the uplink communication link from the current Wi-SUN to the cellular mobile network or the narrowband Internet of Things.

[0085] Further, when the uplink communication link of the Wi-SUN gateway is switched from the cellular mobile network or the narrowband Internet of Things to the Wi-SUN network, the second network quality evaluation result is recalculated based on the updated second link quality evaluation parameter to determine whether the uplink communication link after the switch is normal, that is, whether the recalculated second network quality evaluation result is less than the second preset evaluation threshold; if not, the current uplink and downlink communication mode is maintained; if so, the original uplink wireless link access mode is restored, that is, the original uplink communication link is restored to the connection mode of the cellular mobile network or the narrowband Internet of Things.

[0086] Similarly, when the uplink communication link of the Wi-SUN gateway is switched from the Wi-SUN network to the cellular mobile network or the narrowband Internet of Things, the first network quality evaluation result is recalculated based on the updated first link quality evaluation parameter to determine whether the uplink communication link after the switch is normal, that is, whether the recalculated first network quality evaluation result is less than the first preset evaluation threshold; if not, the current uplink and downlink communication mode is maintained; if so, the original uplink wireless link access mode is restored, that is, the original uplink communication link is restored to the connection mode of the Wi-SUN network.

[0087] In addition, the first preset evaluation threshold and the second preset evaluation threshold can be dynamically adjusted according to the link quality before and after the switch to adapt to different communication conditions and ensure the stability and reliability of the network. For example, when the signal strength decreases after the communication link is switched, the first preset evaluation threshold and the second preset evaluation threshold can be appropriately lowered to trigger the link switching mechanism earlier; when the signal is stable or rising after the communication link is switched, the first preset evaluation threshold and the second preset evaluation threshold can be appropriately increased to reduce unnecessary link switching and improve the stability and efficiency of communication.

[0088] The communication link switching method for heterogeneous networks of this embodiment constructs a network link quality weighted evaluation model for cellular mobile networks, narrowband Internet of Things and Wi-SUN networks, and monitors and evaluates the communication link quality of different types of networks according to real-time link quality evaluation parameters and the network link quality weighted evaluation model, so as to intelligently identify the quality status of the current communication link; and when the link quality of any network is lower than a preset threshold, the method can quickly trigger the switching action of the communication link, and switch the uplink communication link of the gateway from a network with poor quality to a network with better quality, which not only significantly improves the stability and reliability of the communication link, but also effectively avoids communication interruption or data loss caused by poor network quality, thereby optimizing the overall network communication performance and ensuring the continuity and reliability of data transmission.

[0089] Example 2

[0090] The difference from Embodiment 1 is that the communication link switching method of a heterogeneous network in this embodiment further includes the following steps:

[0091] Step S5, obtaining a comprehensive network link quality evaluation result according to the first network quality evaluation result and the second network quality evaluation result.

[0092] Exemplarily, a weighted average method can be used to obtain a comprehensive network link quality assessment result, that is, weights are assigned to the first network quality assessment result and the second network quality assessment result based on factors such as network type, application scenario, user preference or historical performance data. These weights can be static (i.e. determined based on fixed rules or policies) or dynamic (i.e. adjusted according to real-time network conditions, user needs or performance goals); or the numerical values ​​of the first network quality assessment result and the second network quality assessment result can be directly compared, and the higher quality assessment result can be used as the comprehensive network link quality assessment result.

[0093] Step S6: dynamically adjust the wireless link monitoring period according to the comprehensive network link quality evaluation result.

[0094] In order to accurately capture the dynamic changes of wireless links, effectively filter out instantaneous link fluctuations and respond quickly to sudden link conditions, the wireless link monitoring cycle can be flexibly adjusted according to the comprehensive network link quality evaluation results. Specifically, when the signal environment is good, the monitoring cycle is appropriately extended to reduce unnecessary resource consumption; when the signal environment is average, the preset monitoring cycle is maintained to ensure normal monitoring; and when the signal environment is poor and network fluctuations are significantly enhanced, the monitoring cycle is quickly shortened to achieve the best balance between stability and agility of link monitoring.

[0095] Preferably, the method for adjusting the wireless link monitoring period is as shown in formula (11):

[0096] (11)

[0097] In the formula, is the adjusted wireless link monitoring period, is the adjustment factor, and its value range is 0-1. To synthesize the network link quality assessment results, The monitoring period is set.

[0098] The communication link switching method of the heterogeneous network of this embodiment achieves resource optimization and energy saving by dynamically adjusting the wireless link monitoring period according to the first network quality evaluation result and the second network quality evaluation result, and at the same time responds quickly when the network quality is poor, thereby improving stability.

[0099] The following is a detailed explanation of the heterogeneous network communication link switching method of the present application using 4G cellular mobile network and Wi-SUN wireless communication protocol as the application environment.

[0100] Example 3

[0101] like Figure 2 As shown, the heterogeneous network in this embodiment includes an AMI main station and at least one Wi-SUN root router (BR, Border Router). Each Wi-SUN root router is connected to the AMI main station, and its uplink communication link is a 4G cellular mobile network, and its downlink communication link is a Wi-SUN network. In addition, each Wi-SUN root router manages a Wi-SUN FAN network, which contains multiple measurement nodes (Meter Node), and these nodes are connected to the Wi-SUN root router to which they belong.

[0102] Step S2 includes:

[0103] Step S201, the Wi-SUN root router periodically sends data packets to the AMI master station to test the PRR indicator.

[0104] Specifically, the Wi-SUN root router regularly sends data packets to the AMI master station at predetermined time intervals. These data packets are not only used for normal data transmission, but also for testing the key performance indicators of the uplink communication link, namely the PRR indicator. As can be seen from the above embodiment, the PRR indicator reflects the ratio of the number of data packets successfully sent by each Wi-SUN root router to the AMI master station through its uplink communication link (4G cellular mobile network) to the total number of data packets attempted to be sent, and is an important indicator for measuring the efficiency and quality of the uplink communication link.

[0105] Step S202: When the PRR indicator is lower than a preset PRR threshold, the Wi-SUN root router obtains a first link quality evaluation parameter from the physical layer, and obtains a first network quality evaluation result according to the first link quality evaluation parameter and a first network link quality weighted evaluation model.

[0106] Specifically, when the Wi-SUN root router detects that the PRR indicator is lower than the preset PRR threshold, it indicates that there may be problems with the quality of the uplink communication link. At this time, the Wi-SUN root router will obtain the first link quality evaluation parameter from the physical layer. Then, the Wi-SUN root router will obtain the first network quality evaluation result based on the first link quality evaluation parameter and the pre-built first network link quality weighted evaluation model, which reflects the overall quality status of the current uplink communication link.

[0107] Step S3 includes:

[0108] Step S301: When a first network quality evaluation result is lower than a first preset evaluation threshold, the Wi-SUN root router switches to a relay node, and switches an uplink communication link to a Wi-SUN network.

[0109] When the first network quality evaluation result of the Wi-SUN root router is lower than the first preset evaluation threshold, it indicates that the quality of the uplink communication link between it and the AMI master station is poor, which may lead to unstable connection or communication failure. In order to optimize the communication link, the Wi-SUN root router will perform the following operations: First, the Wi-SUN root router no longer communicates with the AMI master station directly through the 4G cellular mobile network, but switches to the role of a relay node. Secondly, the Wi-SUN root router will find and connect to other nearby Wi-SUN root routers with normal uplink communication links. These normal Wi-SUN root routers, as candidates for relay links, can provide more stable or higher quality uplink communication links. Then, by establishing a connection with a nearby Wi-SUN root router with a normal uplink communication link, the Wi-SUN root router (now acting as a relay node) switches the uplink communication link from the original 4G cellular mobile network to the Wi-SUN network; after completing the above switching, the Wi-SUN root router (now acting as a relay node) will communicate with the AMI master station indirectly through a nearby Wi-SUN root router with a normal uplink communication link. This relay communication method helps bypass poor-quality uplink communication links and ensures stable data transmission.

[0110] Specifically, Figure 2 As shown, when the first network quality evaluation result of a certain Wi-SUN root router is lower than the first preset evaluation threshold, the router will switch to a relay node according to the above steps, and communicate with the AMI master station through a nearby Wi-SUN root router with a normal uplink communication link, thereby optimizing the communication performance of the entire heterogeneous network. In this embodiment, the switching process of the uplink communication link of the Wi-SUN router from the 4G cellular mobile network to the Wi-SUN network is called a forward link switching mechanism.

[0111] like Figure 3 As shown, the heterogeneous network can also include an AMI main station, a Wi-SUN root router and a Wi-SUN relay node, the Wi-SUN relay node is connected to the Wi-SUN root router, the Wi-SUN root router is connected to the AMI main station, and the uplink and downlink communication links of the Wi-SUN relay node are both Wi-SUN networks. At this time, the Wi-SUN relay node and the Wi-SUN root router are in the same Wi-SUN FAN network.

[0112] Similarly, the Wi-SUN relay node regularly sends data packets to the AMI master station at predetermined time intervals. When the Wi-SUN relay node detects that the PRR indicator is lower than the preset PRR threshold, it indicates that there may be problems with the quality of the uplink communication link. At this time, the Wi-SUN relay node will obtain the second link quality evaluation parameter. Then, the Wi-SUN relay node will obtain the second network quality evaluation result based on the second link quality evaluation parameter and the pre-constructed second network link quality weighted evaluation model.

[0113] When the second network quality evaluation result of the Wi-SUN relay node is lower than the second preset evaluation threshold, the relay node switches the uplink communication link from the original Wi-SUN network to the 4G cellular mobile network. At this time, the Wi-SUN router switches from the original relay node to the root router, representing an independent Wi-SUN FAN network to communicate directly with the AMI master station. In this embodiment, the switching process of the Wi-SUN router's uplink communication link from the Wi-SUN network to the 4G cellular mobile network is called a reverse link switching mechanism.

[0114] The overall process of the forward link switching mechanism and the reverse link switching mechanism mentioned in this embodiment can be referred to in detail. Figure 4 to understand. Specifically, after the Wi-SUN gateway is started and initialized, it will use the default uplink / downlink communication mode, and at the same time run the wireless link quality assessment strategy to continuously monitor the status of the communication link. When the Wi-SUN gateway detects that the quality score of the uplink communication link is lower than the preset threshold, it will trigger the dynamic link switching process. The specific switching mechanism is as follows: If the current uplink communication link is a 4G cellular mobile network and the quality is poor, the Wi-SUN gateway will use the forward link switching mechanism described above to try to switch the uplink communication link to the Wi-SUN network; conversely, if the current uplink communication link is a Wi-SUN network and the quality is not up to standard, the Wi-SUN gateway will use the reverse link switching mechanism described above to switch the uplink communication link to the 4G cellular mobile network.

[0115] During the dynamic link switching process, the Wi-SUN gateway will evaluate the quality of the uplink communication link after the switch. If the link quality after the switch meets the requirements, that is, whether it is the second network quality evaluation result after switching to the Wi-SUN network or the first network quality evaluation result after switching to the 4G cellular mobile network, if it is higher than the corresponding preset evaluation threshold, the system will keep the current uplink and downlink communication mode unchanged. However, if the link quality after the switch is still not ideal, the Wi-SUN gateway will revert to the original uplink wireless link access mode to ensure the stability and reliability of communication.

[0116] In addition, through the accumulated historical data, the Wi-SUN gateway can learn the link performance in different environments, thereby continuously optimizing the switching algorithm.

[0117] This embodiment achieves a significant improvement in the communication performance of the power Internet of Things by introducing a comprehensive link quality evaluation and a dynamic link switching mechanism. The communication link switching method of the heterogeneous network of this embodiment can evaluate the link quality in real time, and intelligently select a link with better signal quality and lower latency for communication, thereby ensuring the high reliability of the network. When the link quality is poor, it can quickly switch to a better link, effectively reducing the data loss rate. This mechanism not only improves the efficiency of the power Internet of Things in real-time monitoring and data transmission, but also significantly optimizes the user experience. In addition, the method comprehensively considers the network quality between different wireless communication areas from personal area networks to wide area networks, and realizes a comprehensive evaluation of the stability and reliability of cross-regional network connections by accurately analyzing the physical layer and link layer parameters, so that the link quality can be evaluated more accurately, and rapid fault diagnosis and optimization adjustment can be achieved. More importantly, the method realizes intelligent decision-making and automatic optimization by integrating the link quality data of different wireless networks, thereby further enhancing the stability and reliability of the power Internet of Things and meeting the increasingly complex and changing application requirements.

[0118] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A communication link switching method for a heterogeneous network, characterized in that: The method comprises: Step S1, constructing a first network link quality weighted evaluation model and a second network link quality weighted evaluation model; the first network link quality weighted evaluation model is used to evaluate the link quality of a cellular mobile network or a narrowband Internet of Things, and the second network link quality weighted evaluation model is used to evaluate the link quality of a Wi-SUN network; Step S2, obtaining a first network quality assessment result according to the first network link quality weighted assessment model and the first link quality assessment parameter; obtaining a second network quality assessment result according to the second network link quality weighted assessment model and the second link quality assessment parameter; Step S3: when the first network quality evaluation result is less than a first preset evaluation threshold, switching the uplink communication link from the cellular mobile network or the narrowband Internet of Things to the Wi-SUN network; Step S4: when the second network quality evaluation result is less than a second preset evaluation threshold, switching the uplink communication link from the Wi-SUN network to a cellular mobile network or a narrowband Internet of Things; The heterogeneous network includes an AMI main station and at least one Wi-SUN root router, each of the Wi-SUN root routers is connected to the AMI main station, the uplink communication link of the Wi-SUN root router is a 4G cellular mobile network, and the downlink communication link is a Wi-SUN network; the step S2 includes: Step S201, the Wi-SUN root router periodically sends data packets to the AMI master station to test the PRR indicator; Step S202: When the PRR indicator is lower than a preset PRR threshold, the Wi-SUN root router obtains the first link quality evaluation parameter, and obtains the first network quality evaluation result according to the first link quality evaluation parameter and the first network link quality weighted evaluation model; The step S3 comprises: Step S301: When the first network quality evaluation result is lower than the first preset evaluation threshold, the Wi-SUN root router switches to a relay node, and switches the uplink communication link to the Wi-SUN network; The heterogeneous network includes an AMI main station, a Wi-SUN root router and a Wi-SUN relay node, the Wi-SUN relay node is connected to the Wi-SUN root router, the Wi-SUN root router is connected to the AMI main station, and the uplink communication link and the downlink communication link of the Wi-SUN relay node are both Wi-SUN networks; The step S2 comprises: Step S211, the Wi-SUN relay node periodically sends a data packet to the AMI master station to test the PRR indicator; Step S212: When the PRR indicator is lower than the preset PRR threshold, the Wi-SUN relay node obtains the second link quality evaluation parameter, and obtains the second network quality evaluation result according to the second link quality evaluation parameter and the second network link quality weighted evaluation model; The step S4 comprises: Step S411: When the second network quality evaluation result is lower than the second preset evaluation threshold, the Wi-SUN relay node switches to a Wi-SUN root router, and switches the uplink communication link back to the cellular mobile network or the narrowband Internet of Things.

2. The method for switching communication links in a heterogeneous network according to claim 1, characterized in that: The method further comprises: Step S5, obtaining a comprehensive network link quality assessment result according to the first network quality assessment result and the second network quality assessment result; Step S6: dynamically adjust the wireless link monitoring period according to the comprehensive network link quality evaluation result.

3. The method for switching communication links in a heterogeneous network according to claim 2, characterized in that: The method for adjusting the wireless link monitoring period is shown in the following formula: ； In the formula, is the adjusted wireless link monitoring period, is the adjustment factor, is the comprehensive network link quality evaluation result, The monitoring period is set.

4. The method for switching communication links in a heterogeneous network according to claim 1, characterized in that: The expression of the first network link quality weighted evaluation model is: ； In the formula, Indicates the link quality score of the cellular mobile network or narrowband IoT. is the normalized received signal strength, is the weight of the received signal strength, is the reference signal strength of the received signal after normalization, is the weight of the received signal reference signal strength, is the normalized signal to interference plus noise ratio, is the weight of the signal to interference plus noise ratio, is the normalized packet reception rate, is the weight of the packet receiving rate.

5. The method for switching communication links in a heterogeneous network according to claim 4, characterized in that: The values ​​of the weights in the first network link quality weighted assessment model are as follows: ； ； ； ； In the formula, is the received signal strength, is the reference signal strength of the received signal, is the signal to interference plus noise ratio, is the packet receiving rate.

6. The method for switching communication links in a heterogeneous network according to claim 1, characterized in that: The expression of the second network link quality weighted evaluation model is: ； In the formula, Score the link quality of the Wi-SUN network. is the standardized link quality indicator, is the weight of the link quality indicator.

7. The method for switching communication links in a heterogeneous network according to claim 6, characterized in that: The values ​​of the weights in the second network link quality weighted assessment model are as follows: ； ； ； In the formula, Indicates the link quality.

8. The method for switching communication links in a heterogeneous network according to claim 1, characterized in that: The method further comprises: Step S7: dynamically adjust the first preset evaluation threshold and the second preset evaluation threshold according to the link quality before and after the switching.

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