7signal | The Wi-Fi Performance Company

Top 10 Wi-Fi Performance Issues

In Wi-Fi network environments, users face many challenges with their experience. Workers are increasingly mobile and want to bring their own devices (BYOD). The sheer quantity of wireless devices on the network is stretching the boundaries of the original design intent. In addition, workers want instant, anywhere, anytime access to the systems and applications that help them be productive.

As a result, Wi-Fi troubleshooting has become an expensive and time consuming task. However, the video below demonstrates how 7signal uses its Sapphire Analyzer software to quickly identify and troubleshoot many Wi-Fi performance issues.

The Top 10 Wi-Fi Issues and Challenges network administrators face.

  1. Wireless access point rate control is set too aggressively. When too high a rate is selected, an increase in retries ensues, which leads to higher utilization and a lower signal to noise ratio. As a result of this decrease in available air time, capacity and TCP throughput collapse. Our recommendation is to make rate control dynamic, adjusting it based on observed radio conditions.
  2. Automated channel control algorithms need major improvement. We have observed that the automated channel selection features provided by wireless access point vendors can sometime be detrimental to the user experience. The continuous channel hopping that takes place across the network creates an unstable network environment. Despite what your vendor might recommend, we have observed that in certain situations a manual channel plan is more effective.
  3. Wireless radio settings are not understood, therefore, not set properly. These settings include those associated with data rates, control traffic data rates, fragmentation process, Quality of Service, Ack/block-ack schemes usage, RTS/CTS process, Long vs. short pre-amble configuration, load-balancing.
  4. Interference due to poor channel coordination and Bluetooth devices. Most channel plans in public places are random resulting in packet loss and jitter on voice calls. Better channel selection algorithms and coordination is needed. For example, when you’re using the Wi-Fi at the coffee shop, your experience suffers due to the noise generated by the Wi-Fi signals from the restaurant next door. A central system that managed both would be optimal, if we could somehow get these storefronts to collaborate in the name of better Wi-Fi experiences for all customers.
  5. Dense beacon intervals loads up the air unnecessarily. The common beacon interval default of 100ms congests the air significantly. In 100ms a person can move about 1 foot. Therefore, is this kind of dense beaconing necessary? Increasing the beaconing interval to 200 or 300ms can have a great impact on Wi-Fi performance and throughput.
  6. Mobile wireless networks interfere with the WLAN’s 2.4 GHz spectrum. When celluar network indoor antennas are within 30 feet of a WLAN access point, and/or Wi-Fi clients, the signal may saturate the receiver with off-band signals and the receiver generates harmonic distortion that lands in the 2.4 GHz band affecting Wi-Fi performance. One suggestion is to add RF band-pass filtering to WLAN access points.
  7. Supporting legacy 802.11 b devices seriously degrades Wi-Fi performance. The throughput benefits of new standards, such as 802.11ac cannot be realized if network administrators are overprotective of the old standards. Phasing out the old  b devices helps the Wi-Fi experience for everyone on the long run.
  8. Access point interoperability issues may degrade Wi-Fi performance. When administrators introduce new radio devices to the network (phones, tablets, laptops), average retry rates tend to increase to about 70%. It’s true that better requirements are needed for client/access point compatibility and interoperability. Live Wi-Fi network performance monitoring and measuring would certainly help identify and isolate these issues.
  9. Wireless access point antennas need a little help. Today’s WLAN radios have omni-directional antennas with good vertical coverage, but poor horizontal coverage. Some RF energy goes where it shouldn’t and antennas try to receive it from directions where there are no clients. Beam steering and more antenna gain in the direction of clients would be better as it would improve throughput and attenuate interference.
  10. No Wi-Fi performance management systems in place. As Dr. Deming, the grandfather of quality, would most certainly say if he were here today, “You cannot improve what you cannot measure”. Just as cellular networks are managed according to service level and key performance indicators, the time has come for Wi-Fi networks to do the same. This is true because of the mission critical importance of reliable Wi-Fi networks today in hospitals, universities, distribution centers and enterprises.

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