Have you considered how the materials that pin your building together might be affecting the quality of your Wi-Fi setup? I’m guessing probably not. Generally speaking; in our homes and at work we don’t seem to have much knowledge about Wireless and Radio Frequency (RF) theory. Why would you? After all, there’s physics involved that you probably don’t need to know. Unless you're an IT professional or you’re keen to delve deeper into something that you use every day of course.
Do you think it would be useful to know how RF propagates? The characteristics and how the Radio Frequencies can behave in certain conditions?
Knowing this can improve your knowledge for the future and the performance of your Wireless environment now.
The intention of this blog is an introduction into a few of the Radio Frequency behaviours and why they are worth considering in your Small Office Home Office (SOHO) environment. Various behaviours occur due to obstacles and changes to the environment that you are in, especially with outdoor setups that are out in the elements.
This is where a signal does not bounce or reflect off of an object, its strength is reduced by absorption into thick materials such as concrete and brick. Although most materials will absorb some amount of an RF signal. For example (plagiarised from the CWNA study book): "a 2.4 GHz signal will be 1/16 the original power after propagating through a brick wall. That same signal will only lose ½ the original power after passing through drywall material." Due to the water content in the human body, us humans are considered a form of absorption too - so high density areas are at risk.
Real life meaning: Have you wondered why downstairs at home your signal is great and upstairs you have 1 bar and you're barely getting connected, if at all? Absorption will be up there with one of the reasons why. It’s not your broadband at fault as most presume! Below is a visual of how the signal reduces.
This is where a wave hits a smooth object (that is larger than itself) and bounces in a different direction. This can create more than one instance of your propagated signal (Multipath). This was once a detrimental issue with the 802.11a/b/g standards until the introduction of MIMO (Multi-Input Multi-Output). 802.11n and 802.11ac utilise these once frowned upon behaviours with MIMO technology.
Real life meaning: If you work in an office space with lots of glass windows and doors etc then you will either be seeing the pros or the cons of Reflection, depending on your setup and the technology used. Make sure your technology is up to date!
Loss or Free Space Path Loss (FSPL) as it’s more technically known, is the most natural form of attenuation. This is simply the decrease of amplitude/signal strength through free space (the air). It's the widening of the waves as it gets further away from the antenna.
Real life meaning: Do you wonder why you can’t get a good enough signal in your garden at home and your Wi-Fi doesn’t work there? Well it’s simply because you are too far away from your Wi-Fi Router (FSPL in effect). This isn’t the only reason but it’s the most common reason in the majority of cases.
There are quite a few Radio Frequency behaviours that I haven’t discussed but I have highlighted the most common. If you have more interest in this area then study RF theory or embark on the CWNA journey: https://www.cwnp.com/certifications/cwna
The below extract Table1 is from the CWNA study book highlighting the attenuation of 2.4 Ghz signals through various materials. I hope you found this blog useful.
As a customer myself I know that we all like to have free Guest Wi-Fi pretty much wherever we go now, it’s a part of our culture. Business owners like to provide this service as well and ultimately allow their customers to promote their business while they’re on-site.
It’s very tempting to opt for the pre-configured Wireless network that comes with your ISPs (Internet Service Providers) Wi-Fi router. I’ve seen a lot of businesses put up signs detailing the Guest Wi-Fi network name (SSID) and password that the customer needs to look for. Some of them on well printed leaflets and some written by hand on small pieces of paper, using details like in Figure 1:
This kind of setup is mostly down to a lack of knowledge in the area and for a quick fix. The purpose of this blog is to highlight the downsides of setting up your own ‘Guest Wi-Fi’ service. This is from both a technical and business point of view.
The use of ISP equipment and legacy technology
There are many draw backs with using ISPs equipment. The starting point would be the physical technology itself and its limitations. A Wireless Router is a hybrid device, it’s effectively a router and a mini Access Point all-in-one. A jack of all trades with limited hardware space. Whereas a Wireless Access Point is designed solely for facilitating Wireless networks. See Figure 2 for what an Access Point looks like. It’s the best device to use for a professional service. They allow you to configure many more aspects of Radio Frequency than a Wireless Router does, such as transmit power levels which is important for the coverage of your WiFi.
The equipment quickly becomes dated and businesses end up using legacy physical and 802.11 standards without knowing. Figure 3 shows the standard Sky router config which only offers 2.4Ghz, which is a very contended technology. Wireless routers might also only offer legacy security and encryption like WEP, which is easily cracked.
For a small business offering Guest Wi-Fi the bare minimum you should be running is the following. A dual band environment (2.4Ghz ISM & 5Ghz UNII bands) using these standards 802.11a/g/n/ac via an Access Point if possible. Using these standards allows all public devices to connect to the WiFi apart from legacy clients that are 802.11b. Eliminating 802.11b from your network and its 1, 2, 5.5, 11 Mbps data rate will provide a much greater service for everyone on your Wi-Fi.
Prior to install
A frequency spectrum & protocol analysis should be performed, which a lot of businesses don’t even know about. This will highlight interference from other non-Wi-Fi related devices (Walkie Talkies/Microwaves etc) and also the channels that are being used by other WiFi Routers and Access Points. Having your equipment on the same channel as your neighbour will cause Co-Channel Interference (CCI) which seriously degrades your Wi-Fi. The analysis provides you with this information and enables you to avoid these channels (which you can statically set).
The final technical point
Is about the placement of your Access Point. Many providers such as Sky’s ‘The Cloud’ are installing access points for many venues out there but are not advising their customers about where they should be installed, the optimum location. My local pub has their Sky Wireless Access Point underneath the bar so that it’s out of sight. The Wi-Fi is subsequently very poor for the simple reason that the Radio Frequencies can’t propagate properly as there are many obstructions in the way. Within the Wireless community there is a jovial hashtag called #BadFi by @heyeddie that gives examples of some badly placed Access Points, check it out. Some of them are very interesting to say the least :)
To clarify the placement aspect, you should see an Access Point in the analogy of a ceiling light. For the light to cover the room properly it needs to be up high and in a central location, the same applies to Wireless. Due to various restraints this isn't always possible unfortunately. The location is very important if a top-notch service is to be provided. Figure 4 is an example of a good placement.
From a business point of view