Slow WiFi: what to do?

Different factors may affect the quality of your WiFi throughput. When WiFi is slower than expected, user intervention may be needed. This article provides a list of possible issues and how to solve them.

Generally, the use of WiFi AI is recommended. It provides automated and regular WiFi setting updates, allowing for a reliable and continuous adaption to changing RF environments.

 Overview

Each Plasma Cloud device presents different characteristics and can thus reach different throughput. The first table shows the max WiFi data rates for each model based on different channel widths:

WiFi Data Rates

Maximum Measurable WiFi Throughput

The second table below shows the max throughput per model and channel that can be measured via an HTTP throughput test (i.e. speedtest.net) in a perfect RF environment, defined as:

• Without any WiFi interference;
• A single connected client supporting the same capabilities (802.11n/ac/ax) and WiFi radios (2.4 GHz / 5 GHz / 6 GHz) as the WiFi Access Point it is connected to.

WiFi radio limitations

Some Access Points, such as Plasma Cloud's PA300 and PA300E, are single radio devices exclusively running on the 2.4 GHz band supporting the 802.11n standard. For these devices, the maximum WiFi  throughput measurable by clients is around 140 Mbit/s. If you wish to reach higher speeds, consider deploying a device such as the PAX1800 also running on the 5 GHz band and supporting the WiFi 6 standard (802.11ax) (max 600 mbit/s measurable throughput per band).

Alternatively, you could use our tri-band device, the PAX5400, supporting the WiFi 6 standard (802.11ax) on the 2.4, 5 and 6 GHz bands. The WiFi 6/6E standard currently provides the highest throughput (max 1200 Mbit/s measurable throughput per band).

Narrow channel width

Increasing the channel width allows to improve the WiFi throughput, as maximum WiFi performance is generally achievable only when using maximum channel width. Halving the channel width also halves the maximum achievable throughput. For instance, you can reach up to 432 Mbit/s on the 5 GHz band supporting 802.11ac using the 80 MHz channel width. However, by changing to 40 MHz channel width, the maximum measurable throughput decreases to 200 Mbit/s and 78 Mbit/s for 20 MHz, respectively.

Reducing the maximum channel width can still be beneficial though depending on the RF environment. In fact, the 40 MHz channel width on the 2.4 GHz is rarely used in practice because when there are many neighboring WiFi networks, channel interference penalties often outweigh the gain in throughput. If your network environment is heavily affected by 2.4 GHz signal interference, please consider using a 20 MHz channel width instead.

WiFi signal interference

WiFi signal interference from other nearby WiFi devices or non-WiFi sources such as Bluetooth, microwaves, cordless phones, etc. pose a significant challenge for throughput, especially for outdoor installations in busy neighborhoods. You may find that the measurable throughput of a WiFi client varies throughout the day depending on how actively nearby devices are transmitting data.

Selecting different channels and/or physically moving devices away from each other can help you minimize WiFi signal interference. You may check our radio frequency topology article to learn how to uncover signal interference in your environment and how to select the best WiFi channels to ensure better performance for your network.

Number of connected clients

The WiFi throughput measured by a client directly depends on the number of clients connected to the same WiFi Access Point. The throughput is divided by the number of active WiFi clients. Therefore, the more clients are connected to the same device, the slower the connection will be.

Deploying an Access Point with more radios (such as the PAX5400) or deploying more Access Points can help mitigating the bottleneck caused by large number of connected WiFi clients. However, please ensure to minimize WiFi signal interference when adding more Access Points (see previous section).

Mesh connection

With every mesh hop, the throughput is halved due to the "WiFi store and forward" principle. This is because every WiFi radio must first fully receive the data before forwarding it to the next hop. Thanks to our innovative radio alternating mechanism, Plasma Cloud mesh networks effectively reduce the time of WiFi store and forward in networks comprised of dual-band and tri-band Access Points models. This allows for overall higher throughput compared to other mesh networks. 

Also, all WiFi clients connected to mesh devices share the throughput provided by the common gateway. WiFi clients connected to the same mesh gateway are 'competing' for airtime with all the other mesh participants. Basically, the 140 Mbit/s user measurable throughput mentioned above is shared with all mesh devices and their connected WiFi clients at the same time. Plasma Cloud offers a mesh topology tool to better study and troubleshoot your mesh network. Learn more about it in this article.

Generally, we strongly advise to wire your devices whenever possible. However, when a mesh connection is the only available solution, try to balance the load to the best of your possibilities, either by partly switching to wired connections, by using multiple gateways, or by smartly placing your current mesh devices to reduce the number of hops.

Client throttling

Client throttling, the intentional limiting of an Internet service to regulate network traffic and provide fair throughput share to each client, could give the impression of slow WiFi. Always ensure this feature is configured as needed, without limiting your clients more than expected.

Client device limitations

Even with the best WiFi network, well thought out and perfectly deployed, the measured throughput may not be as expected for some clients. This highly depends on the WiFi standard that the client device supports. For instance, WiFi throughput could be limited because a client device has only one antenna or exclusively supports older WiFi standards. You may check the WiFi standard your client device is using on the Plasma Cloud console (Clients > Capabilities). Also, as reference, please note that most laptops have two antennas, whereas many smartphones only have one antenna and thus their measured throughput may be lower.

Still experiencing slow WiFi and not sure why? Contact us explaining the problem. Please remember to also provide details such as organisation, network, MAC address of the problematic Access Points and anything else that may help us in understanding what is going on.