A method for concurrent access of high-density terminals to a low-power wireless network

Abstract

The present invention belongs to the technical field of low-power wide-area Internet of Things wireless access, and specifically relates to a method for concurrent access of high-density terminals to a low-power wireless network. The method comprises: a gateway monitors the MAC layer access success rate of each frequency channel and determines whether network access congestion occurs; a terminal monitors the sending success rate and determines whether terminal data frame sending congestion occurs; according to whether network access congestion occurs at the gateway, the MAC protocol running on the gateway channel is adjusted; according to whether terminal data frame sending congestion occurs at the terminal, the MAC protocol running on the terminal channel is adjusted; the gateway continues to monitor the MAC layer access idle rate, and if it is found that the network access is in an idle state, the gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode; the terminal switches to the original channel and runs the MAC protocol first mode. The present invention ensures that the channel can be quickly accessed under high terminal concurrency conditions, improves the access capability and reliability of the network, and reduces the power consumption of the terminal.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-power wide-area Internet of Things wireless access, and in particular relates to a method for concurrent access of high-density terminals to a low-power wireless network. Background Art

[0002] Low-power wide-area networks (LPWANs), a new generation of IoT technology, are suitable for IoT communications requiring low power consumption, long distances, low bandwidth, low cost, and multiple connections. IoT wireless access technology requires large-scale, high-density, low-power, low-cost terminals to communicate and interconnect over wide areas. These large-scale industrial applications account for 60% of IoT use cases, making them a promising market. LPWANs, represented by various wireless communication technologies such as LoRa, NB-IoT, and Sigfox, offer practical applications in the IoT industry. Their technical characteristics enable networks to connect a large number of low-speed nodes over a wide area to collect data. In typical industrial IoT scenarios, a large number of terminals coexisting across diverse application types share limited wireless channel resources. The high density of terminals transmitting data at any given moment within wide-area coverage can cause severe network data conflicts, resulting in reduced network throughput and a sharp deterioration in network performance. When a large number of terminals experience conflicts and retransmissions, coupled with the real-time fluctuations in the number of terminals in the scenario, network performance can become extremely unstable. In these high-density terminal deployment scenarios, the method by which terminals access the network concurrently determines the number of terminals that can successfully connect and the optimal data transmission capacity. This allows for the establishment of a multi-objective optimization model for latency, power consumption, and cost to achieve optimal resource allocation. Furthermore, efficient access for massive terminals ensures a stable network, enabling rapid and flexible adaptation to changes in the network environment and maintaining near-maximum throughput.

[0003] The characteristics of large-scale IoT services dictate the massive number of terminal devices. Furthermore, their wireless access technology offers wide coverage, so a gateway must simultaneously communicate with a large number of terminals. Therefore, a key design objective for IoT wireless access technology must be to ensure that network communication remains functional even as the number and density of connected terminals increase significantly. In typical IoT sensor applications, to reduce terminal power consumption, terminals typically enter a sleep or low-power state when the sensors are not detecting an event, thereby extending battery life. Therefore, when most devices are in a monitoring state, network communication demand is low, preventing channel resource congestion and MAC layer access congestion. However, when a large number of terminals within the network simultaneously detect and initiate communication due to a widespread event, high-concurrency services can experience severe access and transmission collisions. Taking into account factors such as different service types and distribution locations, effective congestion handling mechanisms should be designed on both the gateway and terminal sides of the network to reduce collision probability, avoid collisions, and ensure successful network access for as many terminals as possible.

[0004] In summary, in low-power wide-area IoT wireless access technology, severe conflicts caused by high-density deployment of terminals at high concurrency can cause a large number of terminals to be constantly waiting for data retransmission. In addition, factors such as in-band and out-of-band interference, multipath, and shadow fading in the wireless channel can affect the communication quality of the wireless network and continuously worsen terminal power consumption. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a low-power wireless network high-density terminal concurrent access method for high-density terminal Internet of Things application scenarios with large-scale wide-area coverage. A reasonable congestion handling mechanism is designed to reduce the number of terminal data retransmissions caused by collisions, and to achieve efficient transmission from the terminal to the gateway, so as to ensure that the terminal can quickly access the channel under high concurrency conditions, improve the network access capability and reliability, and reduce the power consumption of the terminal.

[0006] The object of the present invention is achieved by: a method for concurrent access of high-density terminals to a low-power wireless network, wherein the wireless network includes at least a terminal and a gateway, and the method comprises the following steps:

[0007] S100: The gateway monitors the MAC layer access success rate of each frequency channel and determines whether network access congestion occurs;

[0008] S101: The terminal monitors the sending success rate and determines whether terminal data frame sending congestion occurs;

[0009] S102: Adjusting the MAC protocol running on the gateway channel according to whether network access congestion occurs at the gateway;

[0010] S103: adjusting the MAC protocol running on the terminal channel according to whether terminal data frame transmission congestion occurs at the terminal;

[0011] S104: The gateway continues to monitor the MAC layer access idle rate. If it finds that the network access is in an idle state, the gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode; the terminal switches to the original channel and runs the MAC protocol first mode; the gateway and the terminal return to step S100 and step S101 respectively.

[0012] The gateway monitors the MAC layer access success rate of each frequency channel including:

[0013] The gateway monitors each reception of terminal access data frames and records the number of correct receptions, incorrect receptions, and empty receptions. The MAC layer access success rate is defined as the ratio of the number of correct receptions to the total number of receptions within the predetermined time T1. The total number of receptions is the arithmetic sum of the number of correct receptions, the number of incorrect receptions, and the number of empty receptions within the predetermined time T1.

[0014] Determining whether network access congestion occurs includes:

[0015] If the MAC layer access success rate is lower than the preset threshold S1, the congestion status judgment is started. If the MAC layer access success rate is lower than the preset threshold S2 within the subsequent T2 time, it is determined that the network access is congested, and the gateway side network congestion processing process is started. Otherwise, the MAC layer access success rate continues to be monitored.

[0016] The terminal monitoring the sending success rate includes:

[0017] The terminal monitors the situation of each data frame transmission and records the number of correct transmissions and the number of transmission failures. The terminal transmission success rate is defined as the ratio of the number of correct transmissions in the predetermined time T3 to the total number of transmissions.

[0018] Determining whether terminal data frame transmission congestion occurs includes:

[0019] If the terminal sending success rate is lower than the preset threshold S3, it is determined that the terminal data frame sending is congested, and the terminal side congestion processing process is started; otherwise, the sending success rate continues to be monitored.

[0020] The method of adjusting the MAC protocol running on the gateway channel according to whether network access congestion occurs at the gateway includes: when network access congestion does not occur, the gateway runs the first mode of the MAC protocol on the channel to which the gateway belongs to access the terminal; when network access congestion occurs, the gateway sets the MAC protocol running on the predetermined channel from the first mode to the second mode, and subsequent terminal access runs in the second mode of the MAC protocol to receive terminal access data frames.

[0021] The method of adjusting the MAC protocol running on the terminal channel according to whether terminal data frame sending congestion occurs includes: when the terminal does not experience data frame sending congestion, the terminal runs the first mode of the MAC protocol; when terminal data frame sending congestion occurs, the terminal sets the running MAC protocol from the first mode to the second mode on the predetermined channel, and subsequently the terminal runs in the second mode of the MAC protocol to send data frames for accessing the gateway.

[0022] The gateway continues to monitor the MAC layer access idle rate, including: if the MAC layer access idle rate monitored by the gateway is greater than a set threshold I1, starting a congestion state judgment, and within a subsequent time T4, if the gateway MAC layer access idle rate is greater than a preset threshold I2, it is determined that the gateway network access is in an idle state, and then stopping the network congestion processing process on the gateway side;

[0023] The gateway stopping the network congestion handling process and setting the channel to the original MAC protocol first mode includes: the gateway setting the channel running the MAC protocol second mode to the MAC protocol first mode, operating in the MAC protocol first mode, and receiving terminal access data frames. If the terminal running the MAC protocol second mode cannot obtain signaling information related to the MAC protocol second mode during the access process, the terminal automatically exits the MAC protocol second mode, switches to the original channel, and runs the MAC protocol first mode, thereby stopping the terminal congestion handling process.

[0024] The first mode and the second mode of the MAC protocol are MAC layer protocols with two different access success rates, and the access success rate of the second mode of the MAC protocol is higher than that of the first mode.

[0025] The first mode of the MAC protocol is a pure ALOHA protocol, and the second mode of the MAC protocol is a slotted ALOHA protocol.

[0026] The method of setting the MAC protocol from the first mode to the second mode on the predetermined channel by the terminal when congestion in sending terminal data frames occurs includes: the terminal enters the predetermined channel, listens to the signaling signal related to the second mode of the MAC protocol, and if no signaling information related to the second mode of the MAC protocol is received within time T5, returns to the original channel to run the first mode of the MAC protocol, and continues to monitor the sending success rate, and when congestion in sending terminal data frames occurs, re-enters the predetermined channel to run the second mode of the MAC protocol.

[0027] Beneficial effects of the present invention: A low-power wireless network high-density terminal concurrent access method of the present invention includes steps S100: the gateway monitors the MAC layer access success rate of each frequency channel and determines whether network access congestion occurs; S101: the terminal monitors the sending success rate and determines whether terminal data frame sending congestion occurs; S102: according to whether the gateway has network access congestion, the MAC protocol running on the gateway channel is adjusted; S103: according to whether the terminal has terminal data frame sending congestion, the MAC protocol running on the terminal channel is adjusted; S104: the gateway continues to monitor the MAC layer access idle rate. If it is found that the network access is in an idle state, the gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode; the terminal switches to the original channel and runs the MAC protocol first mode ; The gateway and the terminal return to step S100 and step S101 respectively; the gateway monitors the network MAC layer access success rate, and when the access success rate is lower than a certain threshold due to high concurrent access, the network congestion processing process is started, and the gateway and the terminal automatically detect and switch the MAC protocol working mode, so that a large number of terminals can achieve more efficient access, slow down the access and transmission congestion of terminal access data frames, reduce terminal access delay, reduce terminal data retransmission and terminal power consumption, and effectively improve the terminal concurrent access success rate in large-scale sensor monitoring applications of the Internet of Things; a low-power wireless network high-density terminal concurrent access method of the present invention realizes efficient transmission from the terminal to the gateway, ensures that the terminal can quickly access the channel under high concurrency conditions, improves the access capability and reliability of the network, and reduces the power consumption of the terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a schematic diagram of a method for concurrent access of high-density terminals to a low-power wireless network.

[0029] Figure 2 This is a schematic diagram of a process in which a gateway monitors access success rate and determines network access congestion in a method for concurrent terminal access to a low-power wireless network of the present invention.

[0030] Figure 3 The present invention is a flowchart of a method for concurrent terminal access to a low-power wireless network with high density, in which a terminal monitors the transmission success rate and determines the congestion of terminal data frame transmission. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings.

[0032] The present invention provides a method for concurrent access of high-density terminals to a low-power wireless network. The low-power wireless network is a typical wireless network feature in IoT sensor monitoring applications. The low power consumption means that the wireless network focuses on controlling the power consumption of the terminal during transmission, and in most applications, the terminal requires battery power. The high-density terminal means that there are a large number of sensor terminals within the management range of the gateway. The high-density terminal concurrent access refers to a large number of sensor terminals within the management range of a large gateway sending service data to the gateway in the same time period. Therefore, the access method described in the present invention is a terminal-to-gateway access method under the technical characteristics of low power consumption, high-density terminals, and concurrency.

[0033] The low-power wireless network includes at least terminals and gateways. The gateway manages a large number of terminals. The terminals carry sensors. When a sensor monitoring event occurs, the terminal sends a sensor data frame to access the gateway. When a large number of terminals within the management range of the gateway detect an event at the same time, it will trigger high-density terminal concurrent access, such as Figure 1 As shown, a method for concurrent terminal access to a low-power wireless network with high density of terminals according to the present invention comprises the following steps:

[0034] S100: The gateway monitors the MAC layer access success rate of each frequency channel and determines whether network access congestion occurs;

[0035] S101: The terminal monitors the sending success rate and determines whether terminal data frame sending congestion occurs;

[0036] S102: Adjusting the MAC protocol running on the gateway channel according to whether network access congestion occurs at the gateway;

[0037] S103: adjusting the MAC protocol running on the terminal channel according to whether terminal data frame transmission congestion occurs at the terminal;

[0038] S104: The gateway continues to monitor the MAC layer access idle rate. If it finds that the network access is in an idle state, the gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode; the terminal switches to the original channel and runs the MAC protocol first mode; the gateway and the terminal return to step S100 and step S101 respectively.

[0039] Furthermore, the gateway monitoring the MAC layer access success rate of each frequency channel includes:

[0040] The gateway monitors each reception of terminal access data frames and records the number of correct receptions, incorrect receptions, and empty receptions. The MAC layer access success rate is defined as the ratio of the number of correct receptions to the total number of receptions within the predetermined time T1. The total number of receptions is the arithmetic sum of the number of correct receptions, the number of incorrect receptions, and the number of empty receptions within the predetermined time T1.

[0041] Furthermore, determining whether network access congestion occurs includes:

[0042] If the above-mentioned MAC layer access success rate is lower than the preset threshold S1, the congestion status judgment is started. If the average MAC layer access success rate is lower than the preset threshold S2 within the subsequent T2 time, it is determined that the network access is congested, and the gateway side network congestion processing process is started. Otherwise, the MAC layer access success rate continues to be monitored.

[0043] Furthermore, in a specific embodiment, the gateway and terminals run a pure ALOHA protocol at the MAC layer before congestion occurs. This protocol's fundamental characteristic is that when a terminal has sensor data to transmit, it sends it directly. If the transmission fails, it will be retransmitted after a random delay. When not transmitting, the terminal is in a dormant or low-power state, significantly reducing terminal power consumption. When all terminals within the gateway's range need to transmit fewer data frames to the gateway, the entire network will not experience congestion, and terminals can significantly save energy, increasing terminal battery life, reducing channel utilization time, and improving channel efficiency.

[0044] The theoretical maximum access success rate for the pure ALOHA protocol is 0.184. Its statistical significance can be expressed as follows: when a terminal operates in pure ALOHA mode, the probability of successfully transmitting a data frame is 0.184, meaning that a successful transmission requires 1 / 0.184 transmissions. The aforementioned "MAC layer access success rate is defined as the ratio of the number of correct receptions within a predetermined time period T1 to the total number of receptions, where the total number of receptions is the arithmetic sum of the number of correct receptions, the number of incorrect receptions, and the number of empty receptions within the predetermined time period T1." In one specific embodiment, assuming T1 is 24 hours, statistics show that within 24 hours, the gateway received 18 correct receptions, 40 incorrect receptions, and 42 empty receptions. Therefore, the MAC layer access success rate is 18 / (18 + 40 + 42) = 0.18.

[0045] Furthermore, to dynamically adapt to changes in service intensity, the setting of T1 can be related to the overall service transmission period or frequency: a longer period results in a longer T1, and a shorter period results in a shorter T1. In one specific embodiment, T1 can be set to 10 times the average of the three consecutive reception intervals preceding the current moment; this indicates monitoring the network access success rate over the past T1 period. If the threshold value S1 is set to 0.85*Smax, where Smax is the theoretical maximum access success rate for the MAC layer protocol, then the threshold S1 indicates that continued monitoring for T2 begins when the access success rate falls below 85% of the theoretical maximum. T2 indicates that if a decrease in the access success rate is observed during T1 monitoring, continued monitoring for T2 is performed to determine whether congestion has occurred. The setting of T2 should take into account the detection of multiple consecutive receptions within a short period of time. In one specific embodiment, T2 can be set to 10 times the time required for the maximum uplink and downlink data frames, equivalent to the time required for 10 uplink interactions given an observation period. Therefore, it can more objectively reflect the phenomenon of high-density concurrency within a short period of time. After monitoring at T2, the threshold S2 is set to 0.8*Smax, indicating that S2 must be lower than S1. S1 is used to detect a possible decrease, while S2 is used to confirm a decrease in the access success rate.

[0046] In a specific embodiment, the process of the gateway monitoring the access success rate and determining the network access congestion is as follows: Figure 2 As shown, the specific process is as follows:

[0047] In step S200, the gateway calculates and dynamically updates T1, running timer T1. T1 is set to 10 times the average of the three consecutive service reception intervals preceding the current moment. For example, if the service reception intervals before the current moment were 8 minutes, 9 minutes, and 10 minutes, respectively, then T1 = 10 * ((8 + 9 + 10) / 3) = 90 minutes, and is continuously adjusted and updated in the form of a sliding time window. If the service reception intervals before the current moment were 1 minute, 3 minutes, and 5 minutes, respectively, then T1 = 10 * ((1 + 3 + 5) / 3) = 30 minutes. The gateway continuously updates T1 using the reception intervals.

[0048] In step S201, the gateway monitors the MAC layer access success rate within time T1. This MAC layer access success rate represents the access success rate of the pure ALOHA protocol, with a theoretical maximum access success rate Smax of 0.184. Within the T1 sliding window, the gateway continuously outputs access success rate statistics within time T1, for example, access success rate S[0.18, 0.181, 0.179, 0.17, 0.155]. When 0.155 appears, the gateway compares this value with the threshold.

[0049] In step S202, the gateway compares the MAC layer access success rate obtained by monitoring with the threshold S1 in real time. If it is higher than S1, the process continues to S201. If it is lower than S1, further judgment is made and the process proceeds to S203.

[0050] In step S203, the gateway monitors the MAC layer access success rate within time T2. Here, the threshold S2 is set to 0.8*Smax, or 0.1472. The gateway needs to continue monitoring the MAC layer access success rate within T2. ​​For example, T2 is 10 times the uplink and downlink interaction time. If the uplink and downlink time is 10 seconds, T2 is set to 100 seconds. In other words, the gateway monitors the access success rate for the next 100 seconds.

[0051] In step S204, the gateway determines whether the access success rate is lower than the threshold S2, that is, whether the access success rate monitored during time T2 is lower than S2. In this specific example, the access efficiency value during time T2 is 0.14, which is lower than S2, and then the process goes to S205.

[0052] In step S205, the gateway determines that the network access is congested, and then starts a network congestion processing process on the gateway side.

[0053] Furthermore, the terminal monitors the sending success rate, including: the terminal monitors the situation of each data frame transmission, and records the number of correct transmissions and the number of transmission failures respectively; the terminal sending success rate is defined as the ratio of the number of correct transmissions to the total number of transmissions within a predetermined time T3. In a specific embodiment, the terminal sending success rate is about 0.18, which means that under the steady state of the network, when the service arrival intensity is one packet to be transmitted per unit time, the success rate is 0.18. However, when the terminal concurrency is very small, the packet success rate is much higher than this value. Therefore, the terminal determines whether the success rate is lower than the threshold value through the statistical value of the sending success rate within the T3 time. If the above-mentioned terminal sending success rate is lower than the preset threshold value S3, it is determined that the terminal data frame sending is congested, and the terminal side congestion processing process is started, otherwise the sending success rate continues to be monitored.

[0054] In a specific embodiment, the process of the terminal monitoring the sending success rate and determining the terminal data frame sending congestion is as follows: Figure 3As shown. In this embodiment, in step S300, the terminal calculates and dynamically updates T3, and runs timer T3. The terminal monitors the sending success rate within the past T3 time, that is, it counts the success rate of sending data frames within the T3 time, which is numerically equal to the number of successful data frame sending and the total number of data frames sent. In a specific implementation, considering that the T3 time is to discover possible sending congestion of the terminal, the T3 time cannot be too long, but the time required for high concurrency in a short period of time must be considered. For example, the time of 10 sending cycles, the time of one sending cycle is equal to the time of sending a data and then receiving a gateway confirmation data frame ACK. For example, if a terminal sending cycle is 10 seconds, then T3 can be set to 100 seconds. The length of T3 can be dynamically adjusted according to the length and intensity of the service data.

[0055] In step S301 , the terminal monitors the sending success rate within the time period T3 , that is, the terminal continuously counts the sending success rate within T3 .

[0056] In step S302, the terminal determines whether the transmission success rate is lower than threshold S3. Specifically, the terminal compares the terminal transmission success rate collected during T3 with S3. Assume the terminal transmission success rate is 0.1, and S3 is set to 80% of Smax. For the pure ALOHA protocol, S3 = 0.184 * 0.8 = 0.1472. If the terminal transmission success rate monitored during T3 is lower than S3, the process proceeds to S303.

[0057] In step S303, the terminal determines that the current state is congestion in sending terminal data frames, and starts a terminal-side congestion processing process.

[0058] Furthermore, the adjusting of the MAC protocol running on the gateway channel according to whether network access congestion occurs on the gateway includes: when network access congestion does not occur, the gateway runs the first mode of the MAC protocol on the channel to which the gateway belongs to access the terminal; when network access congestion occurs, the gateway sets the MAC protocol running on the predetermined channel from the first mode to the second mode, and subsequent terminal access runs in the second mode of the MAC protocol to receive terminal access data frames.

[0059] Furthermore, the adjusting of the MAC protocol running on the terminal channel according to whether the terminal experiences terminal data frame sending congestion includes: when the terminal does not experience data frame sending congestion, the terminal runs the first mode of the MAC protocol; when the terminal data frame sending congestion occurs, the terminal sets the running MAC protocol on the predetermined channel from the first mode to the second mode, and subsequently the terminal runs in the second mode of the MAC protocol to send data frames to the access gateway.

[0060] The first mode and the second mode of the MAC protocol are MAC layer protocols with two different access success rates, and the access success rate of the second mode of the MAC protocol is higher than that of the first mode.

[0061] The first mode of the MAC protocol is a pure ALOHA protocol, and the second mode of the MAC protocol is a slotted ALOHA protocol. Pure ALOHA and slotted ALOHA are typical principle protocols for sensor data acquisition in low-power wireless networks for the Internet of Things. They are used in the specific embodiments of the present invention to illustrate the generality and benefits of the method provided by the present invention.

[0062] Furthermore, the gateway changes the MAC protocol running on the predetermined channel from the first mode to the second mode. In a specific embodiment, the gateway turns off the pure ALOHA mode running on the predetermined channel and turns on the slotted ALOHA mode. The gateway supports at least two or more independent frequency channels, and the gateway has at least one channel that is predetermined to be changed from the first mode of the MAC protocol to the second mode.

[0063] Furthermore, the terminal switches the MAC protocol running on the predetermined channel from the first mode to the second mode. In a specific embodiment, the terminal activates the second mode of the MAC protocol on the predetermined channel, that is, activates the slotted ALOHA mode on the predetermined channel. The terminal enters the predetermined channel and listens for signaling signals related to the second mode of the MAC protocol. If no signaling information related to the second mode of the MAC protocol is received within time T5, the terminal returns to the original channel to operate in the first mode of the MAC protocol and continues to monitor the transmission success rate. When congestion occurs in the transmission of terminal data frames, the terminal re-enters the predetermined channel to operate in the second mode of the MAC protocol. In a specific embodiment, the T5 time is set to enable the reception of signaling signals for the second mode of the MAC protocol. The T5 time should be at least twice the slotted ALOHA signaling period.

[0064] Furthermore, the gateway continues to monitor the MAC layer access idle rate, including: if the gateway monitors the MAC layer access idle rate to be greater than a set threshold value I1, then initiating congestion status judgment; if the gateway MAC layer access idle rate is greater than a preset threshold value I2 within a subsequent time period T4, it is determined that the gateway network access is in an idle state, and the gateway side network congestion processing process is stopped; the gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode, including: the gateway sets the channel running the MAC protocol second mode to the MAC protocol first mode, operates in the MAC protocol first mode, and receives terminal access data frames. If the terminal running the MAC protocol second mode cannot obtain signaling information related to the MAC protocol second mode during the access process, it automatically exits the MAC protocol second mode, switches to the original channel, and runs the MAC protocol first mode, then the terminal congestion processing process is stopped; in a specific embodiment, the idle rate refers to the ratio of the number of gateway receptions to the total number of receptions within a period of time, such as T1. The lower the idle rate, the lower the channel utilization, indicating that the terminal sends less data. Setting threshold I1 refers to setting the gateway access idle rate threshold. In a steady-state system, the idle rate of a slotted ALOHA system is approximately 0.368. Therefore, if it approaches twice this value, or 0.736, it is considered excessively idle. Therefore, here we set I1 = 0.736. If the gateway detects that the access idle rate reaches I1 in slotted ALOHA mode, it stops the network congestion handling process and sets the channel to the original MAC protocol first mode.

[0065] The method of setting the MAC protocol from the first mode to the second mode on the predetermined channel by the terminal when congestion in sending terminal data frames occurs includes: the terminal enters the predetermined channel, listens to the signaling signal related to the second mode of the MAC protocol, and if no signaling information related to the second mode of the MAC protocol is received within time T5, returns to the original channel to run the first mode of the MAC protocol, and continues to monitor the sending success rate, and when congestion in sending terminal data frames occurs, re-enters the predetermined channel to run the second mode of the MAC protocol.

[0066] The terminal switches to the original channel and runs the first mode of the MAC protocol. In a specific embodiment, it is characterized in that: the gateway stops the network congestion processing process and sets the channel to the original first mode of the MAC protocol. If the terminal running the second mode of the MAC protocol cannot obtain the signaling information related to the second mode of the MAC protocol during the access process, it will automatically exit the second mode of the MAC protocol, switch to the original channel, run the first mode of the MAC protocol, and stop the terminal congestion processing process.

[0067] The above-described embodiments merely represent several specific implementations and examples of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, and all such modifications and improvements fall within the scope of protection of the present invention.

[0068] In summary, a method for concurrent access of high-density terminals to a low-power wireless network of the present invention includes the following steps: S100: a gateway monitors the MAC layer access success rate of each frequency channel and determines whether network access congestion occurs; S101: a terminal monitors the transmission success rate and determines whether terminal data frame transmission congestion occurs; S102: adjusting the MAC protocol running on the gateway channel according to whether network access congestion occurs at the gateway; S103: adjusting the MAC protocol running on the terminal channel according to whether terminal data frame transmission congestion occurs at the terminal; S104: the gateway continues to monitor the MAC layer access idle rate. If it is found that the network access is in an idle state, the gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode; the terminal switches to the original channel and runs the MAC protocol first mode; the gateway and the terminal return to step S100 and step S101 respectively; the gateway monitors the network MAC layer access success rate, and when the access success rate is lower than a certain threshold due to high concurrent access, the network congestion processing process is started, and the gateway and the terminal automatically detect and switch the MAC protocol working mode, so that a large number of terminals can achieve more efficient access, slow down the access and transmission congestion of terminal access data frames, reduce terminal access delay, reduce terminal data retransmission and terminal power consumption, and effectively improve the terminal concurrent access success rate in large-scale sensor monitoring applications of the Internet of Things; a low-power wireless network high-density terminal concurrent access method of the present invention realizes efficient transmission from the terminal to the gateway, ensures that the terminal can quickly access the channel under high concurrency conditions, improves the access capability and reliability of the network, and reduces the power consumption of the terminal.

Claims

1. A method for concurrent terminal access in a low-power wireless network with high density, wherein the wireless network comprises at least terminals and a gateway, characterized in that: It includes the following steps: S100: The gateway monitors the MAC layer access success rate of each frequency channel and determines whether network access congestion occurs; S101: The terminal monitors the sending success rate and determines whether terminal data frame sending congestion occurs; S102: Adjusting the MAC protocol running on the gateway channel according to whether network access congestion occurs at the gateway; S103: adjusting the MAC protocol running on the terminal channel according to whether terminal data frame transmission congestion occurs at the terminal; S104: The gateway continues to monitor the MAC layer access idle rate. If the network access is found to be in an idle state, the gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode. The terminal switches to the original channel and runs the MAC protocol first mode. The gateway and the terminal return to step S100 and step S101 respectively. The adjusting of the MAC protocol operated by the gateway channel according to whether network access congestion occurs at the gateway includes: when network access congestion does not occur, the gateway operates the first mode of the MAC protocol on the channel to which the gateway belongs to access the terminal; when network access congestion occurs, the gateway changes the MAC protocol operated by the predetermined channel from the first mode to the second mode, and subsequent terminal access operates in the second mode of the MAC protocol to receive terminal access data frames; The adjusting the MAC protocol running on the terminal channel according to whether the terminal has terminal data frame transmission congestion includes: when the terminal does not have data frame transmission congestion, the terminal runs the first mode of the MAC protocol; when the terminal data frame transmission congestion occurs, the terminal changes the running MAC protocol from the first mode to the second mode on the predetermined channel, and subsequently the terminal runs in the second mode of the MAC protocol to send data frames to the access gateway; The gateway continues to monitor the MAC layer access idle rate, including: if the MAC layer access idle rate monitored by the gateway is greater than a set threshold I1, starting a congestion state judgment, and within a subsequent time T4, if the gateway MAC layer access idle rate is greater than a preset threshold I2, it is determined that the gateway network access is in an idle state, and then stopping the network congestion processing process on the gateway side; The gateway stops the network congestion processing process and sets the channel to the original MAC protocol first mode, including: the gateway sets the channel running the MAC protocol second mode to the MAC protocol first mode, runs in the MAC protocol first mode, receives terminal access data frames, and the terminal running the MAC protocol second mode cannot obtain signaling information related to the MAC protocol second mode during the access process, then automatically exits the MAC protocol second mode, switches to the original channel, and runs the MAC protocol first mode, then stops the terminal congestion processing process.

2. The method for concurrent access of high-density terminals to a low-power wireless network according to claim 1, wherein: The gateway monitoring the MAC layer access success rate of each frequency channel includes: The gateway monitors each reception of terminal access data frames and records the number of correct receptions, incorrect receptions, and empty receptions. The MAC layer access success rate is defined as the ratio of the number of correct receptions to the total number of receptions within the predetermined time T1. The total number of receptions is the arithmetic sum of the number of correct receptions, the number of incorrect receptions, and the number of empty receptions within the predetermined time T1. Determining whether network access congestion occurs includes: If the MAC layer access success rate is lower than the preset threshold S1, the congestion status judgment is started. If the MAC layer access success rate is lower than the preset threshold S2 within the subsequent T2 time, it is determined that the network access is congested, and the gateway side network congestion processing process is started. Otherwise, the MAC layer access success rate continues to be monitored.

3. The method for concurrent terminal access to a low-power wireless network with high density according to claim 1, wherein: The terminal monitoring the sending success rate includes: The terminal monitors the situation of each data frame transmission and records the number of correct transmissions and the number of transmission failures. The terminal transmission success rate is defined as the ratio of the number of correct transmissions in the predetermined time T3 to the total number of transmissions. Determining whether terminal data frame transmission congestion occurs includes: If the terminal sending success rate is lower than the preset threshold S3, it is determined that the terminal data frame sending is congested, and the terminal side congestion processing process is started; otherwise, the sending success rate continues to be monitored.

4. The method for concurrent terminal access to a low-power wireless network with high density according to claim 1, wherein: The first mode and the second mode of the MAC protocol are MAC layer protocols with two different access success rates, and the access success rate of the second mode of the MAC protocol is higher than that of the first mode.

5. The method for concurrent terminal access to a low-power wireless network with high density according to claim 4, wherein: The first mode of the MAC protocol is a pure ALOHA protocol, and the second mode of the MAC protocol is a slotted ALOHA protocol.

6. The method for concurrent terminal access to a low-power wireless network with high density according to claim 1, wherein: The method of setting the MAC protocol from the first mode to the second mode on the predetermined channel by the terminal when congestion in sending terminal data frames occurs includes: the terminal enters the predetermined channel, listens to the signaling signal related to the second mode of the MAC protocol, and if no signaling information related to the second mode of the MAC protocol is received within time T5, returns to the original channel to run the first mode of the MAC protocol, and continues to monitor the sending success rate, and when congestion in sending terminal data frames occurs, re-enters the predetermined channel to run the second mode of the MAC protocol.

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