Internet of Things wireless transmission method based on dynamic arbitrary polarized antenna

Abstract

The invention provides an Internet of Things wireless transmission method based on a dynamic arbitrary polarized antenna, which belongs to the technical field of wireless networks, and comprises the following steps: a master station finds a slave station to establish communication by adjusting the polarization direction of the antenna, and sends a handshake signal to establish communication; after communication is established, the master station periodically sends a judgment signal to the slave station, receives a feedback signal of the slave station, and judges whether the slave station needs to adjust the antenna polarization direction according to a polarization signal quality CQI result of the feedback signal; and the slave station performs switching when judging that the polarization direction of the antenna needs to be adjusted based on the judgment signal, calculates CQI data and feeds back the CQI data to the master station. According to the invention, the antenna with the adjustable polarization direction is matched with baseband processing and signaling protocols, so that the master station and the slave station can carry out adaptive polarization direction switching, and a reliable, stable and rapid communication state is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless networks, and in particular relates to an Internet of Things wireless transmission method based on a dynamic arbitrary polarization antenna. Background Art

[0002] With the advent of the 5G era, the development of wireless communications in the Internet of Things is very rapid, and it is inevitable that an environment with multiple terminals and multiple wireless communication technologies will be created. Figure 1 As shown in the figure, the signal is transmitted between the master station and multiple groups of slave stations. Due to the reflection of objects in the path, the polarization direction may change, which also brings about the multipath effect. Since the location and antenna polarization direction of each station are different, if you want to achieve safe and stable transmission in a multi-terminal and multi-antenna environment, you need to put forward higher requirements on the reliability, stability, and even power consumption of the transmission technology.

[0003] Traditional solutions often use multiple antennas and gain compensation to compensate for the loss during transmission. However, this approach will increase power consumption, affect the service life of the device, and bring new problems. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention discloses an Internet of Things wireless transmission method based on a dynamic arbitrary polarization antenna.

[0005] To achieve the above object, the technical solution of the present invention is as follows: The method for wireless transmission of the Internet of Things based on a dynamic arbitrary polarization antenna comprises the following steps: Step 1: The master station adjusts the polarization direction of the antenna to find the slave station to establish communication, and sends a handshake signal to establish communication; Step 2: After establishing communication, the master station periodically sends a judgment signal to the slave station, receives a feedback signal from the slave station, and judges whether the slave station needs to adjust the antenna polarization direction based on the polarization signal quality CQI result of the feedback signal; the slave station judges based on the judgment signal when the antenna polarization direction needs to be adjusted, and calculates the CQI data; when the CQI meets the requirements, it determines the appropriate channel; The CQI calculation formula is: CQI = f (BLER) + f (RSSI), BLER is the block error rate, and RSSI is the received signal strength.

[0006] Furthermore, the step 1 specifically includes the following process: The master station sets the default polarization direction of the antenna and sends a "handshake" request to the slave station. Then, the master station waits for the slave station to reply. When the slave station replies, the communication is established successfully, and the subsequent steps of sending judgment instructions are started. If no reply is received for a long time, the master station switches the polarization direction of the antenna and sends the "handshake" request again. When the slave station replies, the communication is established successfully, and the subsequent steps of sending judgment instructions are started. If the number of "handshake" requests sent exceeds the limit and no reply is received from the slave station, the master station sends an error.

[0007] Further, when the master station switches the polarization direction, the planned directions of the slave stations that have established communication with the master station are modified.

[0008] Furthermore, the step 2 specifically includes the following sub-steps: Step 2-1, the master station sends a judgment signal, which includes: a slave station address, a polarization direction switching instruction, and a test data packet; Step 2-2, after receiving the judgment signal, the slave station determines the polarization direction switching instruction, and switches the polarization direction when the polarization direction switching is required; the slave station calculates the CQI and feeds it back to the master station; Step 2-3, after the master station receives the feedback signal sent by the slave station, it makes a judgment based on the CQI: when the CQI is greater than the threshold, the master station maintains the judgment signal until the next feedback signal is received; when the CQI is less than the threshold, the master station updates the judgment signal, requiring the slave station to switch the antenna polarization direction, and sends the judgment signal in the next time slot, and repeats this step to receive the feedback signal again and make a judgment based on the CQI result until the channel is determined when the CQI is greater than the threshold.

[0009] Furthermore, when switching the polarization direction, a protection period is set before the switching is implemented, and the data that has been encoded and is in the transmission pipeline is processed within the protection period. The polarization direction is switched after the protection period ends and the old polarization data in the transmission pipeline is processed.

[0010] The beneficial effects of the present invention are: The present invention uses an antenna with adjustable polarization direction, combined with baseband processing and signaling protocol, to enable the master station and the slave station to perform adaptive polarization direction switching, alleviate the multipath effect, ensure reliable, stable and fast communication status, and effectively reduce manual operation costs. The method of the present invention avoids over-compensation of gain and can extend the service life of the device (PA).

[0011] The present invention does not need to adopt multiple antenna settings, thus saving costs.

[0012] The method of the present invention adopts a protection period to form a protection mechanism, which can improve communication quality and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of signal transmission between the master station and multiple groups of slave stations.

[0014] Figure 2 Schematic diagram of the adjustable antenna structure.

[0015] Figure 3 Schematic diagram of the communication process between the master station and the slave station.

[0016] Figure 4 Schematic diagram of main station monitoring.

[0017] Figure 5 This is a schematic diagram of slave station feedback.

[0018] Figure 6 Schematic diagram of the polarization direction switching stage. DETAILED DESCRIPTION

[0019] The technical solution provided by the present invention will be described in detail below in conjunction with specific embodiments. It should be understood that the following specific implementation methods are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0020] The network environment for implementing the scheme of the present invention should at least include a master station and several groups of slave stations, and communication is established between the master station and the slave station. The antennas of the master station and the slave station have the function of adjusting the polarization direction. The polarization direction adjustable antenna is a single antenna, supports dynamic polarization reconstruction, and supports sending and receiving. The present invention uses dynamic polarization to resist adverse environments such as multipath fading, interference and signal shielding, so that the sending and receiving antennas have the same polarization direction, achieving high system performance and reducing interference. The baseband chips of the master station and the slave station are upgraded to implement the channel quality CQI evaluation algorithm and the polarization mode selection algorithm in the baseband processor. In addition, it is necessary to adopt a suitable signaling protocol, and the wireless protocol stack can be referred to. The signaling message containing channel quality feedback and polarization mode negotiation is adopted in the process of establishing and maintaining the wireless link. The data packets transmitted between the master and slave stations are encoded and modulated using an adaptive codec method to dynamically adjust the transmission parameters according to the real-time link quality, and further optimize the utilization efficiency of wireless resources. The slave station antenna uses adaptive antenna polarization mode to switch polarization direction: 1. When the CQI of the current polarization mode is detected to be lower than the preset threshold, it can switch to another polarization mode. 2. When the master station notifies the slave station to switch polarization mode, the slave station switches, and the master station should also remain synchronized with the slave station.

[0021] Adjustable antennas are usually Figure 2The disc stacked Yagi structure shown is composed of a half-wavelength dipole driver, a reflector and multiple pilots. In contrast, the adjustable antenna used in the present invention uses 13 circular metal discs as pilots and a patch antenna as a driving element. The patch antenna is also where the liquid metal alloy adjusts the polarization direction. The patch antenna structure is essentially a center-fed circular patch. The patch antenna used in the adjustable antenna in this example is an inner circular patch with a radius of r1 and an outer circle patch with a radius of r2 printed on a RO4350B circular substrate, with a relative dielectric constant of 3.48 and a loss tangent of 0.0037. The radius of the substrate is r and the thickness is d. The other side of the substrate is a metal ground. The gap g between the main radiating plates is 0.5 mm. On top of the patch is a cylinder with a radius of r4 and a height of d1, made of polymethyl methacrylate (PMMA) with a dielectric constant of 3.7. Inside the PMMA cylinder, a circular groove with a height of d2 is formed with a cutter. When this annular groove is located directly above the annular gap g, a microfluidic annular channel is formed. About 1 / 6 of the channel is filled with a small section of liquid metal and sealed with liquid polytetrafluoroethylene (PTFE). It is injected through two PTFE tubes. The inner patch and the outer ring patch are short-circuited at the liquid metal rod. The position of the liquid metal rod can be moved by pumping in a syringe connected to the PTFE tube. This changes the current path on the patch antenna and therefore also changes the polarization direction.

[0022] Before installing the parasitic patch, the position of the liquid metal rod is observed under a microscope and the amount of PTFE injected through the needle is recorded. The parasitic patch and guide are then installed. The polarization direction of the antenna is controlled by the amount of PTFE injected. It must be pointed out that a programmable micro-constant current pump and an accurate cross-polarization calibration procedure are required to produce a more accurate lookup table and relate the polarization direction to the amount of PTFE injected. A circular copper parasitic patch with a radius of r3 and a thickness of d3 is further stacked on top of the PMMA cylinder to improve impedance matching and bandwidth. The antenna is excited using a 50Ω semi-rigid coaxial cable at the center of the patch. The geometry of the entire antenna has rotational symmetry, and changes in the position of the liquid metal do not affect the impedance matching. Continuous polarization adjustment within a range of 180° can be achieved by adjusting the liquid metal rods on the semicircle.

[0023] Based on the above hardware environment, the present invention provides an Internet of Things wireless transmission method based on a dynamic arbitrary polarization antenna, comprising the following steps: Step 1: Initialization The master station adjusts the antenna polarization direction and finds the slave station to establish communication by sending a handshake signal. The handshake signal includes: master station address, pointing address, request instruction, etc.

[0024] Specifically, Figure 3As shown in the figure, the direction from the master station to the slave station is the downlink channel, and the direction from the slave station to the master station is the uplink channel. The master station receives instructions from the upper layer to communicate with the slave station a. The master station sets the default polarization direction of the antenna and sends a "handshake" request to the slave station a. Then, the master station waits for the slave station a to reply: when the slave station a reply is received, the communication is successfully established, and the subsequent steps of sending judgment instructions are started; when no reply is received for a long time, the master station switches the antenna polarization direction and sends the "handshake" request again. When the slave station a reply is received, the establishment is successful, and the subsequent steps of sending judgment instructions are started; if the master station still does not receive a reply from the slave station after sending the "handshake" request three times, the master station sends an error to the upper layer.

[0025] When the master station establishes communication with another group of slave stations b through a "handshake" request, the polarization direction of the master station may change again. If you want to maintain the communication quality of slave station a, you need to modify the polarization direction of slave station a to adapt to the master station.

[0026] Step 2: Master Station Monitoring After establishing communication, the master station periodically sends a judgment signal to the slave station, receives the feedback signal from the slave station, and judges whether the slave station needs polarization direction adjustment based on the CQI result of the feedback signal. The process is as follows: Figure 4 shown.

[0027] (1) First, the master station sends a judgment signal, which includes: a slave station address, a polarization direction switching instruction (such as a polarization direction switching judgment bit), and a test data packet.

[0028] (2) If Figure 5 As shown, after the vertical / horizontal polarized antenna of the slave station receives the judgment signal, it determines the switching instruction of the master station to the antenna to see whether polarization direction switching and demodulation are required. If no switching is required, the working state is maintained. If switching is required, the antenna polarization direction is switched according to the antenna switching principle. A set of polarization mode coding (Zadoff-Chu sequence) needs to be agreed between the master and slave stations, including polarization direction and CQI expression. In this example, the polarization mode uses 1 bite data. When the polarization mode is 0, it indicates vertical polarization, and when the polarization mode is 1, it indicates horizontal polarization.

[0029] After the slave station calculates the polarization signal quality (CQI Channel Quality Indication) corresponding to the test data through the baseband, it is uniformly fed back to the master station. The feedback signal includes: slave station address, slave station antenna polarization direction information, and CQI processing result. CQI is used to reflect the downlink channel quality received by the slave station and serves as a basis for determining whether to switch the antenna polarization mode in the future. CQI can be obtained through the following data: signal-to-noise ratio (SNR), bit error rate (BER / PER), received signal strength (RSSI), multipath delay spread information, etc. In this example, CQI is measured and processed by the baseband, and the calculation formula is as follows: CQI = f(BLER) + f(RSSI) The BLER value can be obtained under the SINR condition and weighted conversion is performed according to the limit of BLER<10%. The RSSI value is compared with the theoretical result under the condition of direct communication between the master station and the slave station and weighted conversion is performed according to the theoretical value.

[0030] The CQI value occupies 4 bits, with a maximum value of 15 (1111). In this example, the judgment threshold is set to: >7 (0111). The slave station reports the CQI value periodically (such as in each transmission gap) or triggered. When the two reporting methods occur at the same time, the triggered reporting method prevails. The slave station reports the CQI value through the uplink control channel or the in-band feedback channel.

[0031] (3) The master station receives the feedback signal sent by the slave station and makes a judgment based on the CQI result: when the CQI is greater than the threshold, the master station maintains the judgment signal until the next feedback signal is received; when the CQI is less than the threshold, the master station updates the judgment signal, requires the slave station to switch the antenna polarization direction, and sends the judgment signal in the next time slot, and repeats this step to receive the feedback signal again and make a judgment based on the CQI result until the CQI is greater than the threshold; the channel is determined.

[0032] like Figure 6 As shown, the polarization direction switching is divided into three stages: Switching notification: After the master station decides to switch the polarization mode according to the adaptive algorithm, it needs to first notify the slave station of the new polarization mode encoding to be switched through control signaling.

[0033] Protection period: If the slave station is switched immediately after notifying it, the slave station will not be able to demodulate correctly. Therefore, it is necessary to protect the data that has been encoded and is in the transmission pipeline from being affected. Therefore, a protection period is used to protect these data, and no switching is performed during the protection period. The above protection mechanism ensures that data will not be lost during the switching of the antenna polarization direction by the method of "caching" and then "sending".

[0034] Switching implementation: After the protection period ends and the old polarization data in the transmission pipeline is processed (whether the processing is completed needs to be confirmed), the master station and the slave station synchronously switch to the new polarization mode encoding and start using the new polarization mode for data transmission.

[0035] The present invention adopts a timing synchronization mechanism for switching: when switching the polarization mode, it is based on the time slot or frame structure, and the switching timing is precisely controlled. The master station indicates the specific switching effective timestamp (such as the number of time slots) in the judgment signal. The slave station adjusts the local timing accordingly and switches the polarization mode at the specified timestamp. The slave station compares the timestamp to determine whether the switching effective time has exceeded. If it has timed out but has not switched, it is considered to be out of sync with the master station mode and enters the protection mode. In the protection mode, the master station demodulates the two polarization modes in parallel and selects the demodulation output with better reception quality. After the protection mode lasts for a period of time, if the receiving end detects that the transmitting end has switched, it also switches to the same mode.

[0036] When the master station is monitoring, it will no longer actively switch the polarization direction of the antenna. The master station monitors each slave station independently.

[0037] The present invention can also use artificial intelligence methods to evaluate and make decisions on polarized channels, thereby achieving better transmission effects.

[0038] It should be noted that the above content only illustrates the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.

Claims

1. An Internet of Things wireless transmission method based on a dynamic arbitrary polarization antenna, characterized in that: The steps include: Step 1: The master station adjusts the polarization direction of the antenna to find the slave station to establish communication, and sends a handshake signal to establish communication; Step 2: After establishing communication, the master station periodically sends a judgment signal to the slave station, receives a feedback signal from the slave station, and judges whether the slave station needs to adjust the antenna polarization direction based on the polarization signal quality CQI result of the feedback signal; the slave station judges when it needs to adjust the antenna polarization direction based on the judgment signal, switches, and calculates the CQI data and feeds it back to the master station; when the CQI meets the requirements, determines the appropriate channel; The CQI calculation formula is: CQI = f (BLER) + f (RSSI), BLER is the block error rate, and RSSI is the received signal strength.

2. The method for wireless transmission of the Internet of Things based on a dynamic arbitrary polarization antenna according to claim 1, characterized in that: The step 1 specifically includes the following process: The master station sets the default polarization direction of the antenna and sends a "handshake" request to the slave station. Then, the master station waits for the slave station to reply. When the slave station replies, the communication is established successfully, and the subsequent steps of sending judgment instructions are started. If no reply is received for a long time, the master station switches the polarization direction of the antenna and sends the "handshake" request again. When the slave station replies, the communication is established successfully, and the subsequent steps of sending judgment instructions are started. If the number of "handshake" requests sent exceeds the limit and no reply is received from the slave station, the master station sends an error to the upper layer.

3. The method for wireless transmission of the Internet of Things based on a dynamic arbitrary polarization antenna according to claim 2, characterized in that: When the master station switches the polarization direction, the planned directions of the slave stations that have established communication with the master station are modified.

4. The method for wireless transmission of the Internet of Things based on a dynamic arbitrary polarization antenna according to claim 1, characterized in that: The step 2 specifically includes the following sub-steps: Step 2-1, the master station sends a judgment signal, which includes: a slave station address, a polarization direction switching instruction, and a test data packet; Step 2-2, after receiving the judgment signal, the slave station determines the polarization direction switching instruction, and switches the polarization direction when the polarization direction switching is required; the slave station calculates the CQI and feeds it back to the master station; Step 2-3, after the master station receives the feedback signal sent by the slave station, it makes a judgment based on the CQI: when the CQI is greater than the threshold, the master station maintains the judgment signal until the next feedback signal is received; when the CQI is less than the threshold, the master station updates the judgment signal, requiring the slave station to switch the antenna polarization direction, and sends the judgment signal in the next time slot, and repeats this step to receive the feedback signal again and make a judgment based on the CQI result until the channel is determined when the CQI is greater than the threshold.

5. The method for wireless transmission of the Internet of Things based on a dynamic arbitrary polarization antenna according to claim 1, characterized in that: When switching the polarization direction, a protection period is set before the switching is implemented. The data that has been encoded and is in the transmission pipeline is processed within the protection period. The polarization direction is switched after the protection period ends and the old polarization data in the transmission pipeline is processed.

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