What is Non-Line-of-Sight (NLOS) communication?

In wireless communication systems, Line-of-Sight (LOS) communication is generally regarded as the ideal condition for signal transmission — there is no physical obstruction between the transmitter and the receiver, allowing the signal to propagate along a straight path with low attenuation and stable channel characteristics. However, in real-world environments, Non-Line-of-Sight (NLOS) communication is the norm. Due to factors such as topographic undulations, dense buildings, vegetation coverage, or electromagnetic interference, it is often impossible to establish a true, direct, and unobstructed line-of-sight path between the two communicating parties (the transmitter and the receiver). In such cases, the signal must bypass obstacles via indirect paths such as Reflection, Scattering, or Diffraction to reach the receiver.

Although NLOS communication can expand coverage range, it also gives rise to corresponding issues. For instance, during propagation, the received signal strength may experience significant attenuation due to differences in path length, medium absorption, or varying characteristics of reflective surfaces. Meanwhile, the superposition of signals from multiple propagation paths at the receiver leads to the Multipath Effect, which manifests as phase interference, delay spread, and frequency-selective fading — in layman’s terms, this means signals interfere with each other. These characteristics result in NLOS communication having far lower stability and reliability than LOS scenarios. Therefore, when deploying wireless devices, efforts are usually made to avoid wireless communication in NLOS scenarios as much as possible.

Despite the challenges of signal attenuation and multipath interference in NLOS scenarios, GuoXin Longxin has developed a variety of targeted solutions from multiple dimensions by integrating various specialized wireless communication technologies and engineering practices. The integration of these technologies enables stable NLOS communication in complex environments and makes it a key supporting technology for modern wireless network coverage. This article will conduct an in-depth discussion focusing on the technologies and methods for addressing NLOS communication issues, as well as their application cases.

I. Challenges of Non-Line-of-Sight (NLOS) Communication

Why does NLOS have a significant impact on the quality of wireless communication? Before delving into the challenges faced by NLOS communication, let’s first briefly introduce the influences of the Fresnel radius and Doppler effect on wireless signal transmission.

1. Fresnel Radius and Doppler Effect

The Fresnel radius is a key parameter that describes the size of the first Fresnel zone—a critical region along the propagation path of wireless electromagnetic waves. In wireless communication, signals do not propagate along a single straight line (the line-of-sight path) but instead spread out.

The Fresnel zone refers to an ellipsoidal region that surrounds this straight-line path and plays a decisive role in signal propagation. The first Fresnel zone is the most critical part of these zones, as it concentrates 60% of the total energy of the wireless signal. If this zone is blocked by physical obstacles, the signal strength will attenuate significantly, further leading to increased latency and even packet loss.

In plain and simple terms: Imagine drawing a line between the transmitter and receiver of a wireless communication system. If there is an obstacle blocking this line, it is “Non-Line-of-Sight (NLOS)”—this is easy to understand. However, in reality, even if there is no obstacle blocking the line itself, if there are obstacles within the Fresnel zone, the communication is still considered “NLOS”.

The Doppler effect is a physical phenomenon where, when there is relative motion between a signal source (e.g., a base station) and a receiver (e.g., a client device), the frequency of the signal received by the receiver changes. This phenomenon is very similar to a daily-life experience: when a fire truck approaches, the pitch of its siren sounds higher, and when it moves away, the pitch sounds lower.

In some cases, wireless devices are stationary relative to each other. However, high-speed moving “dynamic obstacle” particles brought by extreme weather such as sandstorms, heavy rains, and hailstorms will heavily fill the signal propagation path. After the transmitter of a wireless device emits an electromagnetic wave with a frequency of f₀, the wave encounters some particles moving toward the receiver during propagation. When these particles reflect the signal, their own movement will cause a “Doppler shift”: after the particles receive the signal with a frequency of f₀, the reflected frequency will increase to f₀ + f₁ due to the particles’ movement. At this point, the frequency of the signal received by the receiver is no longer the original f₀, but includes f₁ introduced by the moving particles—and this f₁ is the Doppler effect we observe.

The Doppler effect causes frequency offset, which in turn destroys the orthogonality between subcarriers, leading to inter-symbol interference and demodulation errors. When the bit error rate exceeds the threshold of forward error correction capability, the system will activate the retransmission mechanism, resulting in packet loss. This severely impairs the signal transmission quality of wireless devices. It is thus evident that the “Non-Line-of-Sight (NLOS)” scenario involving moving obstacles is far more complex.

2. Generalized and Narrow-Sense Non-Line-of-Sight (NLOS) Communication

To more accurately understand the obstruction issues encountered in wireless communication, we systematically categorize NLOS communication into two dimensions: “generalized” and “narrow-sense”.

1) Generalized Non-Line-of-Sight (NLOS) Communication

Here, generalized NLOS communication refers to scenarios where the communication link is not established in an ideal, unobstructed free space, but operates in a complex, dynamic, and multi-dimensional propagation environment. The term “obstruction” in this context broadly encompasses all factors that render the direct path ineffective or cause severe signal degradation. These include:

Diversity of obstructions: This includes not only static obstacles (e.g., buildings, hills) but also dynamic obstacles (e.g., moving crowds, vehicles, rotating wind turbines).
Complexity of channels: Signal propagation paths are multiple and time-varying, leading to significant multipath effects.
Pervasiveness of interference: Beyond path obstructions, the system may also face electromagnetic interference from other devices, environmental noise (e.g., rain attenuation, hailstorms, sandstorms), and inherent time-variability of the channel (e.g., channel sharing by other wireless devices).

The following factors all fall into this category:

Static obstacles: Building walls, mountain bodies, underground structures.
Dynamic obstacles: Human bodies, vehicles, moving robotic arms.
Environmental interference: Heavy rainfall, sandstorms, hailstorms, strong magnetic fields, electromagnetic pulses.
Channel time-variability: Continuous changes in channel characteristics caused by the movement of communication devices (e.g., mobile phones, drones) or the environment (e.g., swaying tree leaves).

2) Narrow-Sense Non-Line-of-Sight (NLOS) Communication

Narrow-sense NLOS communication specifically refers to scenarios where one or more fixed, static physical obstacles explicitly block the direct path between the transmitter and the receiver. In such cases, communication can only be established through physical mechanisms such as signal reflection, scattering, and diffraction. Key features include:

Explicitness of obstructions: Obstacles are physical entities with relatively fixed positions, sizes, and materials.
Determinism of propagation paths: NLOS communication primarily relies on predictable reflective surfaces (e.g., wall surfaces, glass curtain walls) or specific diffractive paths.
Focus of problems: The main challenges center on overcoming path loss, utilizing specific reflective paths, and addressing the resulting multipath interference.

The following factors all fall into this category:

Building walls: Office partitions, concrete floors.
Hills or terrain: Natural obstacles that block the line of sight.
Vehicles or large equipment: Objects that remain stationary at a specific location for an extended period, causing obstruction.

Under normal circumstances, during the deployment of wireless devices, it is common to encounter terrain undulations or high-rise buildings that directly block signal paths. This forces signals to propagate through complex paths involving reflection, diffraction, and other mechanisms. To avoid multipath effects—where signals from different paths superimpose at the receiver, causing phase interference, increased latency, and signal strength attenuation (which degrades the quality of wireless communication data transmission)—efforts are made to place wireless devices under LOS communication conditions as much as possible. In particular, narrow-sense NLOS transmission (i.e., transmission blocked by fixed, static obstacles) is avoided.

So, how can wireless devices maintain stability and reliability when facing such NLOS communication scenarios? GuoXin Longxin has adopted a variety of technologies to address NLOS communication challenges for such scenarios.

II. Technologies and Methods for Addressing Non-Line-of-Sight (NLOS) Communication

Traditional wireless devices often struggle to tackle the complex challenges of NLOS communication. However, GuoXin Longxin (retain the original name; adjust if an official English name is available) comprehensively leverages a variety of technologies and methods to resolve issues such as signal attenuation, multipath interference, and unclear propagation paths. Specifically, it overcomes NLOS communication challenges through the synergy of technologies and problem-solving approaches including signal enhancement, interference resistance, dynamic adaptation, and link redundancy, thereby achieving reliable wireless communication.

1. Technologies for Supporting NLOS Communication

1) Enhancing Signal Transmitting and Receiving Capabilities

This is the most direct traditional solution, aiming to ensure sufficient signal strength to either penetrate or bypass obstacles.

Increasing transmit power or device sensitivity: Boosting the output power of the transmitter strengthens the signal, making it easier to penetrate “weak obstacles” (e.g., tree leaves) within the Fresnel zone or retain enough energy to be captured by the receiver after diffraction. Improving sensitivity is a more “intelligent” approach, but its potential for optimization is limited by technical and physical constraints. This method is also restricted by device power consumption and regulatory requirements, so it is not a fundamental solution.
Using directional antennas: Traditional solutions also adopt high-gain directional antennas (e.g., sector antennas, parabolic antennas) to concentrate signal energy for transmission and reception in a specific direction. This can significantly enhance signal strength in the effective direction, enabling the signal to “penetrate” or “bypass” obstacles and improve scenarios where the Fresnel zone is partially blocked.

The wireless devices provided by GuoXin Longxin can combine both methods to enhance signal strength and address NLOS communication. For instance, GuoXin Longxin’s wireless devices feature adjustable transmit power and offer a diverse range of antennas; customized antennas are used based on different communication requirements. For guidance on antenna selection, please refer to the article How to Choose an Antenna?, which provides a detailed explanation of the differences between various antennas, the basic principles of antennas, and other relevant content.

2) Anti-Multipath Interference

In an NLOS communication environment, signals reach the receiver via multiple paths such as reflection and scattering, causing severe multipath interference and intersymbol interference—these are the primary reasons for degraded communication quality.

Equalization Technology: A time-domain equalizer is used to compensate for intersymbol interference caused by the channel. It uses an adjustable filter to “straighten” the signal waveform distorted by the channel and restore the original data. This is a classic method to counteract frequency-selective fading and multipath effects.
OFDM (Orthogonal Frequency Division Multiplexing) Modulation: OFDM is a modern technology whose core idea—decomposing a wideband signal into multiple orthogonal narrowband subcarriers—serves as an efficient solution to multipath interference. The bandwidth of each subcarrier is much smaller than the coherent bandwidth of the channel, so each subchannel can be approximately regarded as a flat-fading channel, thereby avoiding complex equalization issues. Many traditional wireless systems also adopt subchannelization technologies similar to OFDM when facing complex channels.

OFDM is exactly the commonly used technology by our company, GuoXin Longxin, to address multipath interference. Through OFDM, the degradation of signal transmission quality caused by multipath effects from refraction and reflection can be effectively reduced or resolved.

3) Diversity and MIMO Technologies

The core idea of diversity technology is “simultaneous transmission, independent reception,” which uses multiple copies (paths) of signals to counteract channel fading. MIMO (Multiple-Input Multiple-Output) technology, on the physical layer, uses multiple antennas to improve the performance of wireless communication systems.

Transmit-Receive Diversity: Multiple antennas are used at the receiver (diversity reception) or multiple antennas are used at the transmitter (transmit diversity). By receiving multiple signal copies with differences and combining them at the receiver (e.g., maximum ratio combining), the probability of communication interruption caused by obstruction or fading of a single path can be significantly reduced.
Spatial Diversity: Spatial diversity is the most common and effective way to implement transmit-receive diversity. In essence, it is also a type of transmit-receive diversity. Its core idea is to use the physical separation of antennas in space to ensure that the channel fading experienced by signals received or transmitted from different antennas is mutually independent. This means that when the signal of one antenna fades due to obstruction by an obstacle, the signal of another antenna may still maintain strong strength.
For example: GuoXin Longxin’s FibeAir microwave is designed with 1-to-2 diversity. It can effectively reduce the impact of NLOS through spatial diversity, which is particularly effective in cross-water communication scenarios.
MIMO (Multiple-Input Multiple-Output) Technology: It is a technology that uses multiple antennas configured at both the transmitter and receiver to transmit and receive multiple data signals simultaneously. Through spatial multiplexing, it significantly improves data transmission rates; alternatively, through spatial diversity, it enhances signal stability and anti-interference capabilities. Thus, without increasing bandwidth or transmit power, it greatly improves the spectral efficiency and system performance of wireless communication.

Therefore, when designing wireless solutions, GuoXin Longxin usually fully considers the on-site environment and integrates MIMO (Multiple-Input Multiple-Output) technology. It configures multiple independent antennas at the transmitter and receiver to work collaboratively, leveraging transmit-receive diversity and spatial diversity technologies to ensure that there is always a signal that can achieve the effect of LOS communication.

4) Adaptive Adjustment Technologies

When facing NLOS communication caused by channel time-variability, GuoXin Longxin can also use a variety of adaptive technologies, including Automatic Distance Learning (ADI), Adaptive Air Rate (AAR), and Automatic Channel Selection (ACS), to reduce the impact of signal strength degradation, channel instability, and channel interference on wireless signal transmission.

Automatic Distance Learning (ADI): GuoXin Longxin’s wireless devices can automatically determine the transmission distance between devices. The Automatic Distance Learning technology can dynamically adjust the output power of the transmitter based on the communication distance between the two communicating parties. Excessively strong or weak wireless signal quality will affect signal transmission quality: when good signal quality is detected (short distance), the transmit power is automatically reduced; when signal quality degrades (long distance or interference exists), the transmit power is increased accordingly to maintain link stability.
Adaptive Air Rate (AAR): Adaptive Air Rate means that communication devices, based on real-time changes in current channel conditions, monitor indicators such as received signal strength, signal-to-noise ratio, bit error rate, and packet loss rate to evaluate the current channel quality and automatically select the most suitable transmission rate. Its core goal is to maximize network throughput while ensuring the reliability of data transmission.
Automatic Channel Selection (ACS): It refers to the ability of wireless devices to automatically scan the surrounding environment and select a channel with low current interference and good signal quality for communication. Its purpose is to avoid continuous interference caused by fixed channels, thereby improving overall network performance.

5) Link Redundancy Technology

GuoXin Longxin’s link redundancy technology is also applicable to NLOS scenarios. The Virtual Router Redundancy Protocol (VRRP) and Multi-Link Data Mirroring (MLDM) address NLOS communication issues from the perspective of network deployment solutions.

Virtual Hot-Standby Routing (VRRP): A fault-tolerant protocol used to improve network reliability and availability. Its core concept is to group multiple physical router devices into a “virtual router,” providing a unified and stable default gateway for hosts within the local area network (LAN). When the master router fails, the backup router can quickly take over its operations, enabling smooth switching of service traffic. This effectively prevents network outages caused by single-point failures of the gateway.In practical deployment, by deploying dual wireless devices or dual wireless links and using them in conjunction with VRRP, if one wireless link is interrupted due to an NLOS communication scenario, terminal devices such as PLCs and cameras connected to it can be immediately switched to the other wireless link to maintain data transmission. Therefore, VRRP is an ideal solution for NLOS communication in mobile scenarios.
Multi-Link Data Mirroring (MLDM): A high-reliability technology adopted by GuoXin Longxin’s iMAX Wireless Metropolitan Area Network (WMAN). It converges multiple parallel links with different interfaces into a single virtual interface, enabling simultaneous multi-path transmission of the same data.Unlike hot-standby routing and Ethernet rings, MLDM technology does not involve service interruption or switching processes—both hot-standby routing and Ethernet rings require such processes. With MLDM technology, as long as the parallel links are not interrupted simultaneously, data transmission remains uninterrupted. Thus, MLDM not only significantly improves the reliability of network systems but also brings the packet loss rate of wireless systems infinitely close to zero; even single-link switching can be achieved with zero packet loss. This unique wireless communication technology allows the iMAX wireless network to outperform fiber optic rings in terms of reliability, packet loss rate, latency indicators, and switching performance. Therefore, this technology also has practical applications in NLOS scenarios.

For more information about VRRP and MLDM, please refer to the articles Application of VRRP Technology in iMAX Wireless Private Network Deployment and How to Ensure High Reliability of Wireless Network Systems?

6) Low-Frequency MESH Technology

In an NLOS communication environment, signals need to penetrate or diffract around obstacles. In wireless communication, the higher the frequency, the shorter the wavelength, and the weaker the diffraction capability.

GuoXin Longxin’s Huanyou Low-Frequency MESH Ad Hoc Network System operates in a typical frequency band of 1.4GHz. Compared with higher frequency bands such as 5.8GHz, it has stronger diffraction capability and obstacle penetration ability—its signals experience less attenuation when passing through obstacles, enabling more stable communication connections under NLOS conditions. Additionally, since the 1.4GHz frequency band is relatively low, it is less susceptible to interference from other high-frequency devices (e.g., WiFi, Bluetooth, microwave, and millimeter-wave devices).

It is precisely because of the physical characteristics of high power and high sensitivity of Huanyou MESH in the 1.4GHz band that it is naturally more suitable for NLOS communication. Therefore, choosing the 1.4GHz frequency band can be regarded as a physical-layer technical optimization for NLOS communication scenarios. However, lower frequencies correspond to lower available bandwidth. Generally, it is recommended to use the Huanyou Low-Frequency MESH Ad Hoc Network System (equipped with low-frequency anti-interference technology) in scenarios with low bandwidth requirements but high anti-interference demands.

Due to its strong signal, high sensitivity, and support for MESH networking, the Huanyou Low-Frequency MESH System offers excellent application advantages in NLOS scenarios. For detailed information about the Huanyou System’s products, technical features, and selected solutions, please refer to the article Typical Case Collection of Emergency Communication Command.

2. Methods for Addressing Non-Line-of-Sight (NLOS) Communication

During the design and construction of wireless communication systems, scenarios where it is difficult to meet the Fresnel radius requirements (e.g., areas with high mountains, hills, or tall buildings) are often encountered. At the same time, wireless communication access points are widely distributed and scattered geographically. How can we solve the NLOS problem in such scenarios once and for all? Based on years of project experience, GuoXin Longxin has developed two main solution design methods that are well-suited to addressing such NLOS issues.

Multi-Base Station Coverage Solution: In metropolitan area network (MAN) access scenarios ranging from several kilometers to hundreds of kilometers in scale, obstruction of wireless communication by terrain irregularities is inevitable. GuoXin Longxin has proposed a solution based on its project experience: using elevation data from satellite maps to select appropriate locations for deploying wireless base stations (BS). These multiple base stations achieve overlapping coverage, ensuring that wireless MAN customer premise equipment (CPE) falls within the coverage area of multiple BS. Therefore, even if communication between a specific BS and the CPE is disrupted by terrain or obstacles, the CPE can adjust the direction of its antenna to achieve effective access through other BS—redundancy backup is even supported.
Relay Solution: In practical application scenarios, some communication points are located in low-lying areas where base station signals are completely blocked. Even with the deployment of multiple BS, wireless network coverage in these areas remains challenging. In such cases, GuoXin Longxin’s relay method can be used. By deploying dedicated dual-mode relay devices at nearby communication points (one wireless module connects to the BS, and the other connects to the blocked wireless CPE), wireless communication can be realized at low cost and high efficiency without affecting normal data transmission.

In essence, the two methods above convert NLOS scenarios into LOS ones. They also enhance project cost-effectiveness and improve project feasibility, reliability, and availability. Supported by GuoXin Longxin’s extensive project experience and profound wireless technology expertise, NLOS communication has become a problem that can be solved easily and simply. Of course, this “ease and simplicity” is based on a deep understanding of wireless communication and mastery of practical conditions—and more importantly, it relies on the outstanding communication capabilities of GuoXin Longxin’s wireless systems, which are actually difficult to replicate.

In GuoXin Longxin’s article What If Leased Line Costs Are Too High and the System Collapses Due to “Line Disconnection”?, when addressing the question “What if wireless communication requires unobstructed lines but this cannot be achieved in actual deployment?”, it is explained that multi-base station coverage and relay design can be used together to solve obstruction problems.

III. Examples of Typical Non-Line-of-Sight (NLOS) Application Scenarios

1. NLOS Communication Caused by Obstacles

When deploying wireless devices in practice, the problem of NLOS communication caused by static obstacles is often encountered. For instance, in scenarios such as forest fire prevention and water conservancy inspection, uneven terrain poses a major challenge to line-of-sight (LOS) communication. Wireless devices cannot establish a direct line of sight, failing to meet the communication requirements of the Fresnel radius. In such cases, relay technology can be used to overcome the physical limitations of LOS propagation.

In a certain open-pit mine project of Guoxin Longxin, the most suitable technology for deploying scattered video surveillance points in mountainous areas is the use of a wireless metropolitan area network (WMAN) private network. However, there is a significant altitude difference between some video nodes and the data acquisition center, making it impossible to establish direct wireless communication. Meanwhile, several video nodes cannot establish wireless communication with any base station either. Under such circumstances, the “multi-base station cross-coverage deployment + wireless relay” networking solution can be adopted. This solution avoids topographically uneven hills in terms of space and converts the original non-line-of-sight (NLOS) communication, which was blocked by obstacles, into reliable and stable line-of-sight (LOS) communication.

2. Application of Non-Line-of-Sight (NLOS) Communication in Mobile Networking for Ports and Yard Cranes

In mobile networking applications for ports and yard cranes, particularly in remote control or unmanned operation scenarios, extremely high requirements are placed on the reliability and stability of wireless networks. However, non-line-of-sight (NLOS) communication challenges such as obstacle blockage frequently arise in such environments. How to address this issue?

In a certain port project of Guoxin Longxin, the quay cranes need to transmit remote control data to the command center. Additionally, wind power generation facilities are deployed on-site between the quay cranes and the command center, which results in the problem that wireless signals are blocked by the wind power generation columns when the quay cranes are moving.

To address the non-line-of-sight (NLOS) issues caused by the dynamic obstacles of wind turbine blades and the blockage from columns, Guoxin Longxin has adopted spatial diversity technology and VRRP (Virtual Router Redundancy Protocol) technology. These technologies prevent wireless signals from being completely blocked at the same time from a spatial perspective, thereby enhancing the reliability and stability of wireless communication and providing an extremely safe operating environment for the remote control of port machinery.

Non-line-of-sight (NLOS) situations caused by obstructions in mobile scenarios are quite common. Especially in scenarios such as unmanned driving, remotely controlled vehicles and machinery, greater emphasis must be placed on how to avoid and reduce the impact of NLOS. For content related to Guoxin Longxin’s unmanned driving, please refer to the Unmanned Driving High-Reliability Wireless Private Network Solution.

3. Non-Line-of-Sight (NLOS) Communication Caused by Environmental Interference

In extreme weather conditions, environmental factors directly damage the integrity of signal propagation paths, resulting in special non-line-of-sight (NLOS) communication challenges. A typical feature of such scenarios is the dynamic deterioration of channel conditions and the uncontrollability of interference sources.

In a project located in a desert area overseas, after the deployment of a regular wireless monitoring system, signal interruptions and severe network packet loss often occurred due to sandstorms. Our analysis identified the main cause as the Doppler effect induced by the high-speed movement of sand and dust particles, which, when combined with environmental noise, led to a sharp surge in the bit error rate.

After replacing the equipment with Guoxin Longxin’s iMAX Wireless Metropolitan Area Network (WMAN) devices and integrating the multi-link data mirroring technology, a stable wireless link was maintained even during sandstorms, ensuring uninterrupted service transmission and the continuous transfer of basic data.

For NLOS (Non-Line-of-Sight) communication scenarios caused by environmental factors, Guoxin Longxin can address the issue through a combination of multiple technologies. These include: adopting Multi-Link Data Mirroring (MLDM) technology to reduce packet loss and enhance the stability and reliability of signal transmission; integrating VRRP (Virtual Router Redundancy Protocol) technology to improve link redundancy; and utilizing OFDM (Orthogonal Frequency Division Multiplexing) technology to mitigate multipath interference, along with increasing signal transmission strength to reduce wireless signal loss.

4. Application Case of Non-Line-of-Sight (NLOS) Communication Under Electromagnetic Interference

In a strong electromagnetic environment, the transmission of wireless signals is also highly susceptible to interference. How should we respond when such a strong electromagnetic environment affects wireless communication?

When wireless communication encounters ultra-high voltage (UHV) power transmission lines, it will also result in non-line-of-sight (NLOS) communication caused by environmental interference, which is mainly reflected in two aspects: electromagnetic radiation interference and Fresnel zone blocking effect.

UHV power transmission lines themselves are strong sources of electromagnetic radiation. The intense electromagnetic field generated during their operation forms a large interference area along the lines. When wireless signals pass through this area, they will be affected: while receiving useful signals, wireless devices will also receive superimposed background electromagnetic noise from the UHV lines. This directly reduces the signal-to-noise ratio (SNR), leads to an increase in the bit error rate (BER), and causes unstable or even interrupted data transmission.

In addition, the lines of UHV power transmission lines may partially block the first Fresnel zone, resulting in the attenuation of signal energy and an increase in path damage, thereby affecting communication quality. Furthermore, under specific meteorological conditions (such as excessively high humidity), UHV lines may also experience corona discharge, generating electromagnetic noise covering a wide frequency range, which further pollutes communication channels. The ionospheric disturbances caused by the discharge will also reflect and scatter wireless signals, potentially triggering the multipath effect and causing signal phase distortion and delay spread.

For such scenarios, Guoxin Longxin’s multiple NLOS communication technologies and methods can be used together to solve communication problems. For the case of UHV power transmission line monitoring projects, please refer to the Case Sharing of Wireless Networking for Power Tower Monitoring.

Overview

Faced with different non-line-of-sight (NLOS) communication challenges, Guoxin Longxin adopts a combination of multiple technologies and methods to collaboratively solve the networking problems encountered in NLOS scenarios, including enhancing signal strength, applying anti-multipath interference technology, diversity technology, adaptive adjustment technology, data redundancy technology, and low-frequency anti-interference technology.

Years of accumulated project experience enable us to help users avoid or reduce the impact of NLOS during the demand research and scheme design phases. Moreover, during the later construction and commissioning phases, we also have a variety of technologies and methods for solving NLOS communication to assist users in addressing NLOS communication issues. For instance, in interference-prone environments with a large number of wireless communication devices, higher-frequency and lower-millimeter-wave communication technologies can be adopted. This not only proactively avoids communication frequency overlap to reduce interference but also achieves larger bandwidth—a win-win solution. For details about millimeter-wave communication systems, please refer to the Overview of Millimeter-Wave Communication System Technology and Applications.

Even when dealing with NLOS communication in long and narrow enclosed spaces such as tunnels, subways, and mines, or NLOS issues in electromagnetic radiation environments generated by large industrial machinery, Guoxin Longxin can convert NLOS to line-of-sight (LOS) using leaky wave cables, thereby ensuring stable, safe, and reliable wireless communication. For information about leaky wave cables and waveguides, please see the Wireless Private Network Solution for Medium and High-Frequency Leaky Wave Cables.

However, it should be noted that NLOS communication requires meeting certain physical and observable conditions, and more engineering experience is needed in links such as design and implementation; otherwise, communication failure will occur directly.

Guoxin Longxin’s wireless private network networking solutions can solve wireless network networking problems in various scenarios. For difficult and costly networking, and for high-reliability wireless private network networking, choose Guoxin Longxin!

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