How to improve wireless communication signal stability？

1，What is wireless communication

Wireless communication is a communication method that uses the characteristics of electromagnetic wave signals propagating in free space to exchange information .

What does wireless communication include?

LoRa, Bluetooth, GSM, 4G, 5G, WIFI, GPS, etc. are all wireless communications

2，What are the factors that affect wireless communication signals?

Before introducing the influencing factors, let us first understand how electromagnetic waves propagate.

In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy.

Electromagnetic fields propagate in the form of waves, forming electromagnetic waves. Electromagnetic waves are invisible and intangible. We can imagine electromagnetic waves as water waves. When we throw a stone into a river, water waves will form on the water surface, with the stone entering the water as the center and propagating in all directions. Because the air and objects have the effect of absorbing and reflecting electromagnetic waves, electromagnetic waves can only propagate to a limited range in space.

There are many types of electromagnetic waves, such as infrared, ultraviolet, etc. Here we mainly talk about 10kHz-3000GHz radio waves.

Through the propagation of electromagnetic waves, we know that the factors affecting the propagation of electromagnetic waves are as follows

1，Lonosphere,

2, Atmosphere

3, Obstacle:

Obstacles will cause refraction, reflection, and diffraction effects on electromagnetic waves

• Natural terrain (mountains, hills, plains, water bodies)
• The number, distribution, and material properties of artificial buildings
• Vegetation characteristics of the area

4, Signal interference, such as radio transmitters, radar devices, high-voltage lines, etc.

5, Device reception error

How to enchance the wireless communication signal stability?

From the above we can see that there are many factors that affect the propagation of electromagnetic waves. In order to improve the stability of signal transmission, it is necessary to minimize the impact of electromagnetic wave propagation factors.

• For example, by using a dual-frequency or multi-frequency receiver and detecting signals of different frequencies, the delay caused by the ionosphere can be eliminated directly from the difference between multiple signals.
• For tropospheric errors, the satellite altitude cutoff angle can be set to no less than 15, and the difference can be calculated by synchronous observations from two or more observation stations and corrected using the tropospheric model.
• For multipath effects, we can choose to use choke antennas or antennas that can reduce multipath effects at locations with open terrain and no reflective surfaces.
• As for signal interference, the site must be far away from the interference source, such as more than 200m away from the radio transmitter, more than 50m away from the high-voltage line, etc.
• For the feeder system at the equipment level, we need to choose impedance-matched feeders, high-quality materials such as pure copper, and shielded materials to reduce losses in signal transmission. In addition, we need to regularly check the appearance of connectors and wires, and replace any damaged ones in a timely manner to avoid affecting signal reception.

In addition to the antenna, you can choose a high-sensitivity receiver for GPS navigation and positioning

Here below, let's talk about how to choose an antenna to improve signal stability.

• Directional antennas with high gain can significantly improve the directionality of the signal, reduce signal reflection, scattering and other attenuation, thereby enhancing the stability of the signal.
• Installation: Install the antenna in an open area and try to increase the height of the antenna to reduce the number of paths the signal passes through, thereby reducing the multipath effect.
• Multi-antenna technology:

Using multiple transmitting and receiving antennas, spatial diversity and space-time coding of signals can improve the performance of the communication system. MIMO technology can simultaneously use multipath paths to transmit information, converting multipath effects into improved communication performance.

In addition to antennas, we can improve signal transmission stability through the following technologies

Equalization Technology:

The equalizer can process the received signal to reduce or eliminate the inter-symbol interference caused by multipath propagation. By adjusting the phase and amplitude of the received signal, the equalizer can compensate for signal distortion and improve the accuracy of data transmission.

Multi-carrier modulation technology

For example, Orthogonal Frequency Division Multiplexing (OFDM) distributes broadband signals to multiple orthogonal subcarriers, with each subcarrier having a lower signal transmission rate, thereby reducing the impact of multipath effects. OFDM effectively combats time domain distortion caused by multipath by processing in the frequency domain.

Spread Spectrum Technology:

By spreading the signal over a wider frequency band, the signal becomes more robust to multipath effects. Code Division Multiple Access (CDMA) is a widely used spread spectrum technology that distributes a unique chip sequence to each user, spreading the signal in the frequency domain to resist multipath effects.

Conclusion:

Radio wave transmission is affected by many factors, which determines the quality of signal transmission.

Although it is difficult to eliminate the influence of these factors, we can minimize the influence by optimizing the installation location and frequency of the equipment, using high-quality equipment, and adopting multiple technologies such as RTK, equalization technology, spread spectrum, and multi-carrier modulation technology, thereby improving signal stability.