Wi-Fi is great when it works right, but as you may know all too well, it can be a pain when it doesn’t. Signals in the Wi-Fi frequency bands can have a pretty limited range indoors, especially if the building is constructed of higher attenuating materials like brick or concrete. Unlike cables, the data travels via the airwaves and is much more susceptible to interference and multipath, which can reduce Wi-Fi ranges as well.
If you need to increase a wireless network’s coverage substantially, the best route may be adding more access points. However if that isn’t desired due to lack of resources or you only need to extend the coverage slightly, here I discuss other options you might try.
Evaluate interference and channels
Though this first recommendation isn’t directly extending the Wi-Fi, it can certainly help the signals travel further and better. Signals can be greatly reduced when your access points are on overlapping channels or the same channels as neighboring wireless networks. Thus, you want to evaluate the airwaves using a Wi-Fi stumbler that will tell you channel details. For a simple stumbler, consider using free software on a laptop or Android apps on your smartphone or tablet.
Though the majority of access points today have an auto channel function that’s supposed to choose the best channels, their level of accuracy and functionality differ. So it’s best to periodically double-check the channel assignments manually.
In the 2.4GHz band, the only channels that don’t overlap are 1, 6, and 11. This band can be very congested, but for networks with multiple access points, you should try to stick to using those channels. For each access point, choose a channel from those three that have no or the least amount of interference from other access points.
In the 5GHz band, there are many more channels and they don’t overlap if the legacy 20MHz channel-widths are used. They only start to overlap when the 40, 80, or 160MHz channel-widths are used, thus you should avoid explicitly setting your access points to use them if you don’t fully understand how to check the channel-widths and set the channels accordingly.
Remember, don’t’ just check the wireless channels at the access point, but walk around the coverage area to get a better idea of the signals throughout. For instance, a channel may look okay to use from signal levels at the access point, but from where users connect the signal levels may raise or change significantly. Thus check the signals throughout and choose the best overall channels. This is one benefit of manually analyzing the bands and choosing channels yourself; the auto channel feature of access points usually lack the ability to factor in the interference that might exist away from that given access point.
If you do find interference and change to better channels, you may see a noticeable difference in the range of the Wi-Fi. Since there’s less noise and interfering signals, your Wi-Fi signals might come in clearer.
If signal and connectivity issues still persist and it appears to be interference related, it’s best to perform RF spectrum scans to detect and identify any non-Wi-Fi interference.
Use better antenna on the access points
If your access points have external removable antennas, consider purchasing higher gain antennas. Stick with omni-directional antennas if you want the coverage area to be relatively equal in all directions from the access point. On the other hand, if you only need the coverage toward a single direction, consider a directional antenna. Since the number and type of antennas vary between different access points, consult the vendor for any recommendations on different antennas.
Use better wireless adapter or antenna on client
If practical, consider upgrading the wireless adapter and/or antenna on the client device(s), which is best if you only have one or few devices with connectivity issues. For instance, an external USB adapter might provide better range for a laptop than its internal adapter and antenna, especially if the adapter is designed for long-range and/or has a more powerful antenna. For desktops, a wireless adapter with an external base antenna may help. Instead of screwing in the antennas on the back of the PC tower, you can usually place the antennas in a better and higher location.
Move the access points
Before spending money on additional access points or repeaters, consider moving around one or more access points to better serve the indented coverage area. This can be especially useful if proper Wi-Fi surveying and design work weren’t performed during the network’s deployment, or if there’s been physical changes in the building.
For smaller networks, a free simple Wi-Fi stumbler may be okay to perform the surveying, but when you have a couple or more access points it’s best to use a heat-map based Wi-Fi survey tool, such as those from AirMagnet, Ekahau, or TamoGraph. You can load in your floor plan and walk around the building recording the signal levels. This lets you visually see the coverage and other signal info on heat-maps, useful to do before and after any wireless network changes.
Utilize a Wireless Repeater, Bridge, or WDS
An alternative to adding a traditional access point is to extend the Wi-Fi signal using a wireless repeater, bridge, or wireless distribution system (WDS) capable device. This eliminates the need to run cabling out to the access point, thus could be a quicker, more economical, option than adding a traditional access point.
Keep in mind, repeaters aren’t great for overall wireless performance as client devices that connect to them can see their network throughput drastically cut. However, this is more of a problem if client devices are using sensitive applications, like VoWLAN. If they’re only doing casual web surfing, the throughput drop may not even be noticeable.
You can purchase devices that are specifically designed for wireless repeating, but some access points and even consumer-grade routers have this functionality built-in. That is useful so if needed, you can use it as a traditional access point in the future.
When you set up the repeater you’d place it within good signal level of the wireless network so it can connect wirelessly to the network. Then the repeater can accept incoming wireless connections from client devices, looking like a traditional access point to the Wi-Fi devices.
Remember, it’s best to ensure interference isn’t limiting your Wi-Fi ranges before doing anything else. Some quick and easy changes to the channels of your access points may help increase your coverage. Next consider better antennas on your access points and/or on the wireless adapters of your client devices. If you don’t see enough range improvement, double-check the placement of the access points and possibly move them around to better cover the area you desire.
Finally, one of the last options you have before having to run cabling for another access point is to use wireless repeating.
If you do end up having to add more access points, keep in mind simply upgrading from an older wireless standard like 802.11g to 802.11n or ac might provide some coverage boosting. Thus you’ll probably want to perform surveying and design work to help pick the best access point locations and channels.