Method for terminal to autonomously carry out air interface switching in planar networking

Abstract

The invention relates to a method for a terminal to autonomously perform air interface switching in planar networking. The method comprises the following steps: a base station and a terminal included in the planar networking are basically located on the same plane; the terminal receives parameters for autonomously performing air interface switching from the base station; the terminal calculates a start time for measuring the signal quality; at the starting moment for measuring the signal quality, the terminal calculates the signal receiving strength and the signal-to-noise ratio; the signal quality of the original cell is in a weakened state, the signal quality of the target cell is in an enhanced state, and the difference between the received signal strength indication of the target cell and the received signal strength indication of the original cell is greater than a first trigger switching threshold. And when the difference between the signal-to-noise ratio of the target cell and the signal-to-noise ratio of the original cell is greater than a first trigger switching threshold, the terminal autonomously switches the original cell to which the terminal belongs to the target cell.

Description

Technical Field

[0001] The present application relates to the field of wireless communication, and more particularly to a method for a terminal to autonomously perform radio interface handover in a planar network. Background Art

[0002] Currently, the handover strategy of 3GPP is performed at the base station, that is, the terminal sends the measurement results to the base station, and the base station makes the decision. The terminal cannot autonomously perform radio interface handover. In addition, in a planar network system, the radio interface handover method needs to be improved. Summary of the Invention

[0003] The present application provides a method for a terminal to autonomously perform air interface handover in a planar network, including: the base stations and terminals included in the planar network are substantially located in the same plane; the terminal receives parameters for autonomously performing air interface handover from the base station; the terminal calculates the start time for measuring signal quality; at the start time for measuring signal quality, the terminal calculates the signal reception strength and signal-to-noise ratio; when the signal quality of the original cell is in a weakening state, the signal quality of the target cell is in a strengthening state, and the difference between the received signal strength indication of the target cell and the received signal strength indication of the original cell is greater than the first handover trigger threshold, and the difference between the signal-to-noise ratio of the target cell and the signal-to-noise ratio of the original cell is greater than the first handover trigger threshold, the terminal autonomously switches the original cell to which the terminal belongs to the target cell, where, at the start time for measuring the signal, the state of the signal quality of the cell is determined in the following manner: when the current value of the signal-to-noise ratio of the original cell is less than the sliding average value of the signal-to-noise ratio of the original cell, and the current value of the signal-to-noise ratio of the original cell is less than the previous sliding average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a weakening state; when the current value of the signal-to-noise ratio of the original cell is less than the sliding average value of the signal-to-noise ratio of the original cell, and the current value of the signal-to-noise ratio of the original cell is greater than the previous sliding average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a maintaining state, and when the current value of the signal-to-noise ratio of the original cell is greater than the sliding average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a maintaining state; when the current value of the signal-to-noise ratio of the target cell is greater than the sliding average value of the signal-to-noise ratio of the target cell, and the current value of the signal-to-noise ratio of the target cell is greater than the previous sliding average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the target cell is a strengthening state; when the current value of the signal-to-noise ratio of the target cell is greater than the sliding average value of the signal-to-noise ratio of the target cell, and the current value of the signal-to-noise ratio of the target cell is less than the previous sliding average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the original cell is a maintaining state, and when the current value of the signal-to-noise ratio of the target cell is less than the sliding average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the target cell is a maintaining state; where the above sliding average value is determined by performing weighted averaging on the current value of the signal-to-noise ratio of the cell and the previous sampled value of the signal-to-noise ratio of the cell, where the weighting coefficient of the current value of the signal-to-noise ratio of the cell is greater than the weighting coefficient of the previous sampled value of the signal-to-noise ratio of the cell.

[0004] Through the above method, in the system of the planar network, the terminal can automatically perform air interface handover. This method can be applied to the field of vehicle-to-everything (V2X). BRIEF DESCRIPTION OF THE DRAWINGS

[0005] To better describe and illustrate the embodiments of the present application, one or more drawings may be referred to, but the additional details or examples used to describe the drawings should not be considered as limiting the scope of any one of the inventive concepts of the present application, the currently described embodiments, or the preferred modes.

[0006] Figure 1 It is a schematic diagram of a method for a terminal to autonomously perform air interface handover in a planar network according to an embodiment of the present application.

[0007] Figure 2 It is a schematic diagram of preamble sequence filling according to an embodiment of the present application. Detailed implementation manners

[0008] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to 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.

[0009] 3GPP (3rd Generation Partnership Project) is an important standard organization in the field of wireless communication, responsible for formulating the world's leading wireless communication standards. In the wireless communication system of 3GPP, air interface handover is a key technology for ensuring the continuity and stability of communication.

[0010] The following is an air interface handover strategy and method in a typical 3GPP wireless communication system (such as LTE): Interaction between the base station (eNodeB) and the terminal (UE): In the LTE system of 3GPP, the communication between the base station and the terminal is carried out through the air interface (Uu interface). When the terminal communicates within the coverage area of a certain base station, it establishes a wireless connection with that base station. As the leading party, the base station monitors the quality of the wireless connection with the terminal and decides whether an air interface handover is required. Signal quality detection and air interface handover trigger conditions: The base station uses a series of measurement reports and signal quality indicators to evaluate the quality of the wireless connection with the terminal. These indicators include signal-to-noise ratio, received signal strength, bit error rate (BER), etc. When the signal quality is lower than a certain threshold, the base station will trigger the air interface handover process. Specifically, the base station configures a "trigger condition" or "handover threshold", which is a predefined signal quality threshold. When the signal quality of the terminal is lower than this threshold, the base station will initiate the air interface handover process. In addition, the air interface handover can also be triggered by system information broadcast, high-layer signaling, etc. Air interface handover process: When the base station decides to perform an air interface handover, it sends a "handover command" to the terminal. This command contains the identification of the new base station and other necessary information, such as the frequency of the target cell and the global cell identification (ECGI). After receiving this command, the terminal attempts to establish a new wireless connection with the new base station. Processing after successful handover: Once the terminal successfully switches to the new base station, it sends a "handover completion report" to the new base station. The new base station adjusts the communication parameters with the terminal according to this report to ensure the continuity and stability of communication.

[0011] Figure 1It is a schematic diagram of a method for a terminal to autonomously perform air interface handover in a planar network according to an embodiment of the present application.

[0012] Generally speaking, the terminal's air interface handover includes obtaining air interface handover parameters, the terminal measuring information for air interface handover parameters (which includes received signal strength, signal-to-noise ratio), calculating when to start measuring, and determining whether to initiate a handover. Descriptions are given separately below.

[0013] The method for obtaining air interface handover parameters is as follows: After the terminal accesses a certain base station, it interacts with the base station through signaling to obtain an air interface handover parameter table. The air interface handover parameter table may include the following content.

[0014] The air interface handover parameter table includes a measurement type, where the measurement type includes periodic measurement and triggered measurement. When the terminal receives a periodic measurement identifier, it will immediately start the measurement; if it receives a triggered measurement identifier, it will start the measurement again at an appropriate time according to its own signal quality and distance from the base station.

[0015] The air interface handover parameter table includes periodic measurement parameters. Among them, the periodic measurement parameters include a measurement long period (in frames), which is mainly used for the measurement period when the cell signal quality is relatively good. A measurement short period (in frames), which is mainly used for the measurement period when the cell signal quality is relatively poor. The TA threshold for starting long-period or short-period measurement. The received signal strength threshold for starting long-period or short-period measurement.

[0016] The air interface handover parameter table includes triggered measurement parameters. Among them, the triggered measurement parameters include the TA threshold for triggering measurement, the received signal strength threshold for triggering measurement, the signal-to-noise ratio threshold for triggering measurement, and the measurement period after triggering measurement starts.

[0017] The air interface handover parameter table includes general parameters. Among them, the general parameters include the threshold when the signal quality of the original cell is extremely poor. When it is lower than this threshold, as long as the signal quality of the target cell is better than that of the original cell, the handover is initiated; the parameter CalNum that depicts the size of the sliding window of the signal quality change between the original cell and the target cell, and the unit is the number of measurements.

[0018] The air interface handover parameter table includes neighbor cell parameters. Among them, the neighbor cell parameters may include multiple N cells, and the detailed content is as follows: the frequency point of target cell n; the bandwidth of target cell n; the MAC address value of target cell n; the first received signal strength threshold for triggering handover; the second received signal strength threshold for triggering handover; the first signal-to-noise ratio threshold for triggering handover; the second signal-to-noise ratio threshold for triggering handover; the minimum signal strength of the target cell.

[0019] The terminal measures information for air interface handover parameters (which includes received signal strength, signal-to-noise ratio).

[0020] Principle of measurement parameters: Thanks to the EUHT-5G system using the GPS or Beidou synchronization system as a reference to ensure the alignment of the frame headers of adjacent base stations. When performing neighbor cell measurements, energy statistics and signal-to-noise ratio calculations are carried out on the preamble stage of the neighbor cell.

[0021] Received signal strength The calculation method of the received signal strength is as follows:

[0022] Statistical energy of the Preamble stage:

[0023]

[0024] Where: x is the sampling point, and n is the number of sampling points.

[0025] Calculate power

[0026]

[0027] Where: R represents the receiving impedance. P (w) Is the signal power value, and the unit is watt.

[0028] Convert to the unit of dbm (Decibel-milliwatts)

[0029]

[0030] Where: The unit of P is dbm.

[0031] Calculation of received signal strength

[0032] Received signal strength = P - RX_Gain

[0033] Where, the received signal strength is the received signal strength of the RF front end, and the unit is dbm. RX_Gain is the gain value of the receiving link, and the unit is db.

[0034] In one embodiment, the signal power value P calculated by the baseband is -10 dbm, and the typical receiving link gain value is 60 db. Then the received signal strength = -10 - 60 = -70 dbm.

[0035] The calculation method of the signal-to-noise ratio is as follows:

[0036] Respectively statistical signal power Ps and noise power Pn, then the signal-to-noise ratio is:

[0037] SNR = Ps / Pn

[0038] Where, Ps statistically represents the received power in the preamble area, and Pn is the received power in the blank area after subtracting the preamble repetition sequence.

[0039] Specifically, the system of the present application adopts OFDM (Orthogonal Frequency Division Multiplexing) technology. In the Preamble stage, the elements composed of Z sequences are mapped to the frequency-domain spaced subcarriers. As Figure 2 shown, it is a schematic diagram of preamble sequence filling.

[0040] Among them, the shaded part is the filled data, and the blank part has no data. First, calculate the difference between the data in the shaded part and the data in the blank part to obtain the effective signal data sampling set S n , and use equations 1), 2), and 3) in the rssi calculation stage to calculate the effective signal power P S .

[0041] Then, use the blank part data sampling set N n , and also use equations 1), 2), and 3) to calculate the noise power P N .

[0042] Among them, the equations 1), 2), and 3) used in the rssi calculation stage are as follows:

[0043] Statistical energy in the Preamble stage:

[0044]

[0045] Among them: x is the sampling point, and n is the number of sampling points.

[0046] Calculate power

[0047]

[0048] Among them: R represents the receiving impedance. P (w) is the signal power value, and the unit is watt.

[0049] Convert to the dbm (Decibel-milliwatts) unit

[0050]

[0051] Among them: The unit of P is dbm.

[0052] Calculate when to start measurement

[0053] To avoid multiple terminals measuring and initiating handovers simultaneously, the starting point of measurement for each terminal is associated with the current sfn (system frame number), its own MAC value, and period (measurement period). Calculation method: The sum of the Sfn and the MAC value is modulo-operated with the period, and the calculation formula is as follows:

[0054] (sfn + MAC) mod period

[0055] After the terminal accesses the base station, when the sfn is updated to make the result of the above formula equal to 0, the current frame is used as the starting moment for initiating measurement. Since the MAC address of each networked terminal is different and the period also varies, the moments for different terminals to initiate measurement are different.

[0056] In one embodiment, the current sfn = 3814, the MAC of terminal 1 = 26, the period = 128, (3814 + 26) mod 128 = 0; the MAC of terminal 2 = 30, the period = 128, (3814 + 30) mod 128 = 4; it can be seen that at frame 3814, terminal 1 can initiate measurement, but terminal 2 will not.

[0057] In one embodiment, the terminal calculates the starting moment for measuring signal quality and determines it in the following way: sum the system frame number of the base station and the MAC address value of the terminal, and divide the sum by the period for measuring signal quality to obtain the remainder. When the remainder is 0, it is used as the starting moment for the terminal to measure signal quality. Here, the system frame number is a count value used to identify the order of each physical frame. Each time the base station constructs a physical frame, the system frame number is incremented by 1. The range of the system frame number is from 0 to 4095. When it is greater than 4095, the system frame number returns to 0.

[0058] Record and statistically analyze the signal quality of the original cell and the target cell

[0059] After obtaining the valid measurement results of the neighboring cell each time, it is necessary to record the data of the original cell and the target cell. To avoid the ping-pong phenomenon of handover caused by the jump of measurement results, it is necessary to perform a moving average and trend judgment on the results of received signal strength and signal-to-noise ratio.

[0060] For the moving average, take the weighted average of the most recent measurement result and the average value of the previous data. The formula is as follows:

[0061] value = 0.3 × Last_Averge + 0.7 × New_value

[0062] Among them, Last_Averge is the moving average value within the previous statistical period, New_Value is the instantaneous measurement value this time, and Value is the moving average value of this statistics. The coefficient is the weight ratio.

[0063] Judge whether to initiate a handover. This stage includes the trend judgment of the original cell and the trend judgment of the target cell. The handling of invalid measurements of neighboring cells and the handling method of received signal strength.

[0064] 1. Trend judgment of the original cell

[0065] The change trend of the original cell is obtained mainly based on the change in the signal-to-noise ratio. The change trends of the original cell include:

[0066] a) The signal-to-noise ratio becomes weaker;

[0067] b) The signal-to-noise ratio remains

[0068] in two states, and the specific judgment is as follows:

[0069] 1) Each time the moving average of the signal-to-noise ratio of the original cell is calculated, compare the instantaneous value measured this time with the average value within the moving window and the previous average value;

[0070] 2) If the instantaneous value measured this time is less than the average value within the moving window and less than the previous average value, it is regarded that the signal-to-noise ratio becomes weaker this time;

[0071] 3) If the instantaneous value measured this time is less than the average value within the moving window but greater than or equal to the previous average value, it is regarded that the signal-to-noise ratio remains this time;

[0072] 4) If the instantaneous value measured this time is greater than or equal to the average value within the moving window, it is regarded that the signal-to-noise ratio remains this time;

[0073] 5) If the signal-to-noise ratio value drops N (N < CalNum, the value of N is adjustable) times within the statistical window, it is considered that the signal-to-noise ratio trend change is in the weakening state; otherwise, it is considered that the signal-to-noise ratio remains;

[0074] 2. Trend judgment of the target cell

[0075] The change trend of the target cell is obtained mainly based on the change in the signal-to-noise ratio. The change trends of the target cell include:

[0076] a) The signal-to-noise ratio becomes stronger;

[0077] b) The signal-to-noise ratio remains

[0078] in two states, and the specific judgment is as follows:

[0079] 1) Each time the moving average of the signal-to-noise ratio of the target cell is calculated, compare the instantaneous value measured this time with the average value within the moving window and the previous average value;

[0080] 2) If the instantaneous value measured this time is greater than the average value within the moving window and greater than the previous average value, it is regarded that the signal-to-noise ratio becomes stronger this time;

[0081] 3) If the instantaneous value measured this time is greater than the average value within the moving window but less than or equal to the previous average value, it is regarded that the signal-to-noise ratio remains this time;

[0082] 4) If the instantaneous value measured this time is less than or equal to the average value within the moving window, it is regarded that the signal-to-noise ratio remains this time;

[0083] 5) If the received signal strength value becomes stronger N (N < CalNum) times within the statistical window, it is considered that the SNR trend change is in a strengthening state; otherwise, it is considered that the overall SNR remains unchanged.

[0084] 3. Handling of invalid measurements of adjacent cells

[0085] When the measurement value of a certain target cell is empty, it is regarded as an invalid measurement result for this time. If it is empty for the first measurement, the measurement value for this time is not only an invalid value but also does not participate in the subsequent average calculation; if the measurement value becomes empty midway, then the measurement value for this time is replaced by the previous measurement value, but it should be recorded that this measurement is invalid. When the number of invalid measurements exceeds the threshold, the measurement value of this target cell will be reset to invalid. When making handover criterion judgments later, if there are CalNum - m (m value adjustable) invalid values within the CalNum interval for this cell, then this cell will not be used as a candidate target cell.

[0086] 4. Processing method of received signal strength

[0087] The recording and statistical methods of the received signal strength values of the original cell and the target cell are the same as those of the SNR, but do not participate in trend judgment.

[0088] The terminal judges whether to initiate an air interface handover.

[0089] After each measurement and statistics of the signal quality of the original cell and the target cell by the terminal, it also needs to judge whether to initiate a handover to the target cell.

[0090] Embodiment 1

[0091] Regardless of the trend states of the original cell and the target cell, as long as the SNR of the original cell is lower than the threshold when the signal quality of the original cell is extremely poor, and the SNR of the target cell is greater than the SNR of the original cell, a handover to the target cell is triggered.

[0092] Embodiment 2

[0093] The signal quality of the original cell is in a weakening trend, and the signal quality of a certain target cell is in a strengthening trend, satisfying the following conditions:

[0094] The received signal strength of the target cell minus the received signal strength of the original cell is greater than the threshold 2 for triggering handover of the received signal strength;

[0095] The SNR of the target cell minus the SNR of the original cell is greater than or equal to the threshold 2 for triggering handover of the received signal strength. Then a handover to the target cell is triggered. In this case, the target cell is significantly better than the original cell.

[0096] Embodiment 3

[0097] The original cell is in a trend of weakening signal quality, and a certain target cell is in a maintaining trend, satisfying the following conditions:

[0098] If the received signal strength of the target cell minus the received signal strength of the original cell is greater than the threshold 1 for triggering handover received signal strength, and the signal-to-noise ratio of the target cell is greater than the signal-to-noise ratio of the original cell, then trigger the handover to this target cell.

[0099] Embodiment 4

[0100] The signal quality of the original cell is in a maintaining trend, and the target cell is in a trend of strengthening or maintaining signal quality, satisfying the following conditions:

[0101] The received signal strength of the target cell minus the received signal strength of the original cell is greater than the threshold 2 for triggering handover received signal strength.

[0102] The signal-to-noise ratio of the target cell minus the signal-to-noise ratio of the original cell is greater than the threshold 1 for triggering handover signal-to-noise ratio. In this case, it takes 3 measurement periods to initiate the handover to the target cell. The purpose of 3 consecutive measurement periods is to avoid ping-pong handover.

[0103] Embodiment 5

[0104] The original cell is in a trend of maintaining signal quality, satisfying the following conditions:

[0105] The received signal strength of the target cell minus the received signal strength of the original cell is greater than 3 times the threshold 2 for triggering handover received signal strength.

[0106] The signal-to-noise ratio of the target cell is greater than the signal-to-noise ratio of the original cell, triggering the handover.

[0107] Embodiment 6

[0108] Regardless of the states of the original cell and the target cell, satisfying that the signal-to-noise ratio of the target cell minus the signal-to-noise ratio of the original cell is greater than or equal to the threshold 1 for triggering handover signal-to-noise ratio; and, the signal strength of the target cell is greater than the minimum signal strength of the target cell, triggering the handover.

[0109] During the process of judging the triggering of handover, if two or more target cells meet the conditions, then compare the average received signal strength and the average signal-to-noise ratio within the window of multiple target cells, and take the stronger one as the access target cell.

[0110] In summary, the present application proposes a method for a terminal to autonomously perform air interface handover in a planar network, including: the base stations and terminals included in the planar network are substantially located in the same plane; the terminal receives parameters for autonomously performing air interface handover from the base station; the terminal calculates the start time for measuring signal quality; at the start time for measuring signal quality, the terminal calculates the signal reception strength and signal-to-noise ratio; when the signal quality of the original cell is in a weakening state, the signal quality of the target cell is in a strengthening state, and the difference between the received signal strength indication of the target cell and the received signal strength indication of the original cell is greater than the first handover trigger threshold, and the difference between the signal-to-noise ratio of the target cell and the signal-to-noise ratio of the original cell is greater than the first handover trigger threshold, the terminal autonomously switches the original cell to which the terminal belongs to the target cell, wherein, at the start time for measuring the signal, the state of the signal quality of the cell is determined as follows: when the current value of the signal-to-noise ratio of the original cell is less than the moving average value of the signal-to-noise ratio of the original cell, and the current value of the signal-to-noise ratio of the original cell is less than the previous moving average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a weakening state; when the current value of the signal-to-noise ratio of the original cell is less than the moving average value of the signal-to-noise ratio of the original cell, and the current value of the signal-to-noise ratio of the original cell is greater than the previous moving average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a maintaining state, and when the current value of the signal-to-noise ratio of the original cell is greater than the moving average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a maintaining state; when the current value of the signal-to-noise ratio of the target cell is greater than the moving average value of the signal-to-noise ratio of the target cell, and the current value of the signal-to-noise ratio of the target cell is greater than the previous moving average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the target cell is a strengthening state; when the current value of the signal-to-noise ratio of the target cell is greater than the moving average value of the signal-to-noise ratio of the target cell, and the current value of the signal-to-noise ratio of the target cell is less than the previous moving average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the original cell is a maintaining state, and when the current value of the signal-to-noise ratio of the target cell is less than the moving average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the target cell is a maintaining state; wherein, the above-mentioned moving average value is determined by weighted averaging the current value of the signal-to-noise ratio of the cell and the previous sampled value of the signal-to-noise ratio of the cell, wherein the weighting coefficient of the current value of the signal-to-noise ratio of the cell is greater than the weighting coefficient of the previous sampled value of the signal-to-noise ratio of the cell.

[0111] Through the above method, in the system of a planar network, the terminal can automatically perform air interface handover. This method can be applied to the field of vehicle-to-everything (V2X).

[0112] In one embodiment, the start time for the terminal to calculate the signal quality measurement is determined as follows: The system frame number of the base station and the MAC address value of the terminal are summed, and the value obtained after summation is divided by the period for measuring the signal quality to obtain a remainder. When the remainder is 0, it is used as the start time for the terminal to measure the signal quality. Herein, the system frame number is a count value used to identify the order of each physical frame. Each time the base station constructs a physical frame, the system frame number is incremented by 1. The range of the system frame number is from 0 to 4095. When it is greater than 4095, the system frame number is reset to 0.

[0113] In one embodiment, at the start time for measuring the signal quality, the terminal calculates the received signal strength in the following manner:

[0114] Statistical energy of the preamble stage of the frame

[0115]

[0116] where x is the sampling point, n is the number of sampling points, and

[0117] Calculate power

[0118]

[0119] where R represents the receiving impedance, P (w) is the signal power value, and it is further calculated through the following formula

[0120]

[0121] Finally, the received signal strength value is the P value minus the gain value of the receiving link.

[0122] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification.

[0123] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, 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 appended claims.

Claims

1. A method for a terminal to autonomously perform air interface handover in a planar network, including: The base stations and terminals included in the planar network are basically located in the same plane; The terminal receives parameters for autonomous air interface handover from the base station; The terminal calculates the start time for measuring signal quality; At the start time for measuring signal quality, the terminal calculates the signal reception strength and signal-to-noise ratio; When the signal quality of the original cell is in a weakening state, the signal quality of the target cell is in a strengthening state, and the difference between the received signal strength indication of the target cell and the received signal strength indication of the original cell is greater than the first handover trigger threshold, and the difference between the signal-to-noise ratio of the target cell and the signal-to-noise ratio of the original cell is greater than the first handover trigger threshold, The terminal autonomously switches the original cell to which the terminal belongs to the target cell, where At the start time for measuring the signal, the state of the signal quality of the cell is determined by the following method: When the current value of the signal-to-noise ratio of the original cell is less than the sliding average value of the signal-to-noise ratio of the original cell, and the current value of the signal-to-noise ratio of the original cell is less than the previous sliding average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a weakening state; When the current value of the signal-to-noise ratio of the original cell is less than the sliding average value of the signal-to-noise ratio of the original cell, and the current value of the signal-to-noise ratio of the original cell is greater than the previous sliding average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a maintaining state, and when the current value of the signal-to-noise ratio of the original cell is greater than the sliding average value of the signal-to-noise ratio of the original cell, it is determined that the state of the signal quality of the original cell is a maintaining state; When the current value of the signal-to-noise ratio of the target cell is greater than the sliding average value of the signal-to-noise ratio of the target cell, and the current value of the signal-to-noise ratio of the target cell is greater than the previous sliding average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the target cell is a strengthening state; When the current value of the signal-to-noise ratio of the target cell is greater than the sliding average value of the signal-to-noise ratio of the target cell, and the current value of the signal-to-noise ratio of the target cell is less than the previous sliding average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the original cell is a maintaining state, and when the current value of the signal-to-noise ratio of the target cell is less than the sliding average value of the signal-to-noise ratio of the target cell, it is determined that the state of the signal quality of the target cell is a maintaining state; Among them, the above sliding average value is determined by weighted averaging the current value of the signal-to-noise ratio of the cell and the previous sampled value of the signal-to-noise ratio of the cell, where the weighting coefficient of the current value of the signal-to-noise ratio of the cell is greater than the weighting coefficient of the previous sampled value of the signal-to-noise ratio of the cell.

2. The method for a terminal to autonomously perform air interface handover in a planar network according to claim 1, wherein, The terminal calculates the start time for measuring signal quality, which is determined by the following method: Sum the system frame number of the base station and the MAC address value of the terminal, and divide the sum by the period for measuring signal quality to obtain a remainder. When the remainder is 0, it is used as the start time for the terminal to measure signal quality. Among them, the system frame number is a count value used to identify the order of each physical frame. Each time the base station constructs a physical frame, the system frame number is incremented by 1. The range of the system frame number is 0 to 4095. When it is greater than 4095, the system frame number returns to 0.

3. The method for a terminal to autonomously perform air interface handover in a planar network according to claim 1, wherein, At the start time for measuring signal quality, the terminal calculates the received signal strength by the following method: Statistic the energy in the preamble stage of the frame Among them, x is the sampling point, n is the number of sampling points, and Calculate the power where R represents the receiving impedance, and P (w) is the signal power value and is further calculated by the following formula Finally, the received signal strength value is the P value minus the gain value of the receiving link.

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