Troubleshooting Common Issues with Enterprise Wi-Fi Performance

More Wireless Can Mean More Problems

Most users today connect laptops, tablets, and smartphones to enterprise LANs wirelessly. The increasing number of Internet of Things (IoT) devices has further increased users’ reliance on wireless connectivity throughout commercial buildings. The cost-effectiveness, pervasive coverage, versatile data rates, power efficiency, and robust security features of Wi-Fi combine to make it a preferred choice.

Given Wi-Fi's critical role in day-to-day business operations, IT managers must prioritize robust, reliable, and secure wireless performance throughout the enterprise. However, recent advancements in Wi-Fi technology have introduced more operating frequencies, channels, channel widths, and security protocols — all of which also mean more complex configurations and increased potential for problems. Understanding common Wi-Fi issues is essential for you to troubleshoot them effectively.

Illegal and Non-Recommended Wi-Fi Channels

The Federal Communications Commission (FCC) and the International Telecommunication Union (ITU) have allocated the 2.4 GHz, 5 GHz, and 6 GHz frequency bands for Wi-Fi within the ultra high frequency (UHF) electromagnetic spectrum. While earlier generations operated within the 2.4 GHz and/or 5 GHz bands, Wi-Fi 6E expanded to include the 6 GHz band after the FCC opened it up in 2020.

Adjacent and Co-Channel Interference

Wi-Fi interference occurs when wireless signals are disrupted by other wireless signals in the vicinity, leading to slower network speeds and connection delays. Interference can be caused by electromagnetic radiation from external sources running on the same frequency. This typically impacts the 2.4 GHz band, since microwave ovens, cordless phones, Bluetooth devices, and even some lighting can emit noise at this frequency.

• • Adjacent channel interference happens when wireless access points (APs) located close to one another use overlapping channels, causing them to essentially “talk over” each other. This occurs within the 2.4 GHz band where channels overlap. For example, APs in the same area operating on channel 1 and channel 3 can interfere with each other. That’s why it’s best to only use channels 1, 6, and 11 in the 2.4 GHz band.


• • Co-channel interference occurs when two or more APs are using the same channel. This can happen in the 2.4 GHz, 5 GHz, and 6 GHz bands. For instance, two APs operating on channel 36 within the 5 GHZ band can interfere with each other if they are also close physically. Transmit power and coverage area can also impact co-channel interference. Lowering transmit power or increasing the distance between APs on the same channel can help prevent overlapping coverage areas and reduce interference.
  
  In the 5 and 6 GHz frequency bands, using wider 40, 80, or 160 MHz channels for greater throughput increases the probability of co-channel interference, because it reduces the number of non-overlapping channels. For example, an AP operating on the 80 MHz wide channel 42 (channels 36, 40, 44, and 48) can interfere with another AP operating on the 40 MHz wide channel 38 (channels 36 and 40). Carefully configuring a mix of different channel widths in the same environment is essential to avoiding co-channel interference in these bands.

Poor Wi-Fi Signal Strength

Wi-Fi signal strength is measured in decibel milliwatts (dBm), expressed as a negative value. A higher dBm value (closer to zero) indicates a stronger signal. Strong signals correlate with higher data transfer speeds and more reliable connections. A signal strength of -67 dBm or better generally supports most applications like voice and email, while a signal strength of -50 dBm or better is typically preferred for video streaming. If the signal drops to -80 dBm or lower, it’s normally too weak for most applications and may prevent connecting altogether.

Several factors can contribute to poor signal strength:

• • Interference from other wireless signals, excessive distance from the AP, and obstructed line of sight are common culprits.


• • In environments with high ceilings, APs may need to be mounted lower using threaded rod or cable hanging kits to improve signal strength.


• • Horizontal AP orientation is also recommended, whenever possible, for stronger signals.


• • Physical obstacles can also degrade signal strength. While the 2.4 GHz band is more congested and prone to interference, it offers better range and propagation (the ability to penetrate building materials) due to lower signal path loss. The 5 and 6 GHz bands are more susceptible to signal weakening by walls, doors, and furniture, especially materials like concrete and metal.

Conducting a Wi-Fi site survey is essential for determining optimal AP placement in your facility.

High Channel Utilization

Channel utilization measures how busy a Wi-Fi channel is as a percentage of bandwidth used. Experts recommend keeping channel utilization below 50% for optimal voice, data, and video transmission performance. High channel utilization can reduce throughput, increase latency, and lead to packet loss and connection drops.  

• • Interference, including adjacent and co-channel interference from other wireless devices, is a common cause of high channel utilization. A large number of clients on the same channel can also be a factor. If channel utilization is high but client count is low, interference is likely the culprit. While adding more APs might seem like a solution for high utilization due to many clients, it can worsen the problem if they operate on the same channel. Directional antennas in large open areas can help focus coverage and improve channel utilization.


• • Too many wireless networks (SSIDs) can also contribute to high channel utilization. While useful for segregating devices or user groups (e.g., employees and visitors), excessive SSIDs create channel overhead. Older devices with lower data rates exacerbate the issue by occupying more airtime. Upgrading older devices, disabling low data rates on the AP, or assigning a specific channel to slower devices can help mitigate this problem.

Weak Security

Outdated security protocols, outdated firmware, disabled encryption, and weak passwords result in an AP with weak security.

Wireless security protocols have evolved significantly over the years to protect users and networks. WEP, the initial standard, was rendered obsolete due to security vulnerabilities. WPA and WPA2 offered improvements, but WPA3 is the current recommended standard, providing the strongest protection through individualized encryption rather than shared passwords and a secure handshake to enhance authentication. It’s recommended that all APs use the WPA3 protocol.

Comprehensive Analysis Is Essential for Optimal Wi-Fi Performance

Understanding and troubleshooting Wi-Fi is crucial for supporting modern businesses and their wireless devices. Wi-Fi testers capable of analyzing 2.4 GHz, 5 GHz, and 6 GHz bands are essential for optimizing Wi-Fi environments. These tools should provide a snapshot of each channel within each frequency band, identifying overlapping channels, signal strength, and channel utilization. They should also indicate AP-specific data like MAC address, encryption protocol, frequency, channel, signal strength, and data rates.

Fluke Networks has you covered when it comes to maintaining the health of both your wired and wireless networks. We’ve just expanded our award-winning LinkIQ™ Cable+Network Tester with a simple, easy-to-use Wi-Fi testing interface that comprehensively analyzes all your wireless environments, from Wi-Fi 1 through Wi-Fi 6E.

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