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Here’s why you should get a 5GHz Wi-Fi AC router (Part 2: Advantages and Disadvatanges of 5GHz band in IEEE 802.11)
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Here’s why you should get a 5GHz Wi-Fi AC router (Part 2: Advantages and Disadvatanges of 5GHz band in IEEE 802.11)

by Super DaddyJuly 22, 2017

Before we dive deep into the advantages and disadvantages of the 5GHz band in IEEE 802.11, you should read up our earlier article on the history of the 5GHz band to get a better understanding of its journey in order to be able to appreciate the benefits that it will carry. Some of the highlights here will be focused based on the history, so understanding it will make this article more meaningful.

Take note that this article is based on our technical testing environment and our opinions are based on our own user experience and hardware advantages that we have. For our testing, we have used the ASUS RT-AC5300 which is an extremely powerful router but is capable of portraying the real benefits in terms of throughput and signal range. 

Goodbye Interference

Probably one of the most important benefits of having a 5GHz band connectivity is the fact that its less likely to be a culprit of interference compared to 2.4GHz band. As you already know, your device might or might not have 5GHz capabilities, but it will definitely have 2.4GHz capabilities if it works on Wi-Fi.

To understand interference, it is important to understand wave coherence. Two (or more) wave sources are coherent if they have a constant phase difference and modulate at a same frequency. As we already know, our wireless waves are modulating at specific frequencies. When these waves come into contact with each other, there are two scenarios that happen; when they have the same frequency but no phase difference, they are said to be in phase. When they have the same frequency and have phase differences, they are said to be out of phase with each other. When two waves are out of phase and the difference is exactly 180° from each other, they reach an antiphase which creates a destructive interference causing them to cancel each other out.

These phase differences are calculated at every single wave form, which means the interference happens very quickly and rapidly. As a result, your wireless internet packet will have to be reissued, causing a very little delay in the accurate data delivery. The cause of interference itself could be anything between the various smartphones and gadgets that you have, network extenders, smart home appliances, radio control toys, cordless phones, or pretty much anything that has wireless capabilities in them. Because 2.4GHz is the prime choice (I’ll explain why later on), the likeliness of having interference on 2.4GHz band is much higher than 5GHz. Take note of the term “likeliness” that I use repetitively.

Higher Throughput

The 5GHz is capable of offering much higher throughput compared to the 2.4GHz with the same channel width. This is subjective to the hardware that is used, of course. A typical 5GHz band has 23 non-overlapping channels as compared to only 3 offered in the 2.4GHz band. Some newer routers even offer powerful tools and technologies like MU-MIMO, beamforming, WTFast, etc which even enhances the streamlining of the waves.

Some routers like our ASUS RT-5300 has tri-band capabilities to offer even higher total throughput on the 5GHz band. Tri-band means that the router has 2 x 5GHz bands and 1 x 2.4GHz band. The two 5GHz bands in the RT-5300 router are coupled to a load-balancer whereby it will automatically offload devices from one band to another when too many devices connect to one of the bands.

Because the 5GHz has higher maximum speed and wider spectrum of channels, you can connect way more devices to the 5GHz and still maintain excellent speeds compared to 2.4GHz. Think of it as a highway where you have 23 lanes, compared to 3 lanes. If you have only one car on the highway, your limitation is the speed of how fast your vehicle can travel. But when you talk about 50 cars, the significant difference that 23 lanes can bring compared to 3 lanes in terms of congestion is pretty clear.

5GHz vs 2.4GHz throughput speed test

To test this out, I ran a quick test to show the speed difference between both networks. I setup a little local server to which I added SFTP access. Local server, because we want to gauge only the wi-fi transfer speeds without latency from the internet. If I were to test the transfer speed of one single file, I would get pretty much the same results for both network bands. Instead, I increased the limit to 8 concurrent SFTP connections to the server to allow multiple simultaneous downloads, maximizing throughput utilisation.

On my remote server, I uploaded a small NodeJS project file that I had lying around that contains 5 main directories, 75 sub-directories and about 350 files, mix of binary and ASCII based files. Because the SFTP would run a recursive command searching every single file in every sub-directory while transferring, I loaded up the recursive queue first, then processed the queue to ensure minimal discrepancies. I’ve also enabled timestamp logging so we can gauge the time taken for the transfer to complete.

I’ve set the best possible settings for both 2.4GHz and 5GHz bands. The 2.4GHz mode is set to N-only, using channel bandwidth of 40MHz and using the best available control channel (1). The 5GHz mode is set to N/AC mixed, using channel bandwidth of 80MHz and also using the best available control channel (149). Now, to make the results even more significant, I could have set the 2.4GHz to use legacy Wi-Fi mode which is still used in some older routers, but instead, I decided to do a test of best of both worlds – since we have the ASUS RT-5300 anyway. I’m also using the second 5GHz band for this test because it uses 1024-QAM and higher number of available channels.

Each of these transfers were done three times to get the final results. This eliminates any disk caching and other parameters that can affect the outcome.

2.4GHz FTP Transfer test

Our first test begins with the transfer of the 2.4GHz band. The timestamp shows 12:36:24 as the starting time.

Below you can see that the final file transfer completes at 12:37:08 which means the whole queue took about 44 seconds.

5GHz FTP Transfer Test

Then we move on to the 5GHz transfer test. The timestamp shows that the test was began at 12:53:46.

The final file is transferred at 12:54:02 which means the same queue took about 16 seconds to complete.

That’s a pretty staggering difference right there. 44 seconds on the 2.4GHz compared to only 16 seconds on the 5GHz band. This is only based on one user running multiple streams of file transfer. If you have several users on your network, and have multiple devices per users connected to the same router, imagine the difference on a larger scale that it could bring.

Take note also that a part of this speed is also affected by the interference that happens in the 2.4GHz band. The number of 2.4GHz Wi-Fi bands around our testing environment is pretty huge whereas there was only one 5GHz band in our premise which was ours during the test.

Shorter Range & Poorer Wall Penetration

If there is one thing that the 5GHz band doesn’t win over 2.4GHz band, it’s range. Because of higher frequency, 5GHz attenuate faster compared to 2.4GHz causing it to have much shorter range (often almost half) of what 2.4GHz is capable of. 5GHz band also has poorer wall penetration because of its shorter wavelengths compared to 2.4GHz.

Now this is up to you too look at one perspective or another. The good things about having a short range is that 5GHz is almost definitely NOT going to reach your neighbour’s premises. Even if it does in high rises, due to poor wall penetration, they would be getting very poor performance, which gives you an advantage to fully utilise your own high speed internet for yourself. Even if they have the password, connecting to the 5GHz band will be disappointing for them.

On thicker walls (and different material walls), the likeliness of 5GHz to perform better reduces as well. But how far does it really matter? We did a test on the RT-AC5300 to find out about this. The image below depicts the layout of my house where I conducted the test and the position where I have placed the router. There are three different locations where I tested the network performance:

  1. First position is right in front of the router with no interference at all.
  2. Second position is the guest room that passes through one solid brick wall.
  3. Third position is the play room that passes one glass door and one brick wall.
  4. Fourth position is near the entrance that passes two solid brick walls and thick concrete-based staircase.
  5. Fifth position is the furthest corner from the router and passes one solid brick wall.

How does it perform? Let’s look at it one by one. We have Pokde2.4G as the SSID of the 2.4GHz band and Pokde5G-2 as our 5GHz band. Take note that these network are running freely without any devices attached to them (not even my test device) to make sure our results are as accurate as possible without having any load on the router.

Test 01 – Right in front of the router

As you can see, when my test device was right in front of the router, our 2.4GHz band is claiming about -35dBm signal strength and this is very much similar to our 5GHz band. This is our “control” results which is what we will compare against. You can also see the super wide number of channels catered by the 5GHz band that shows how powerful the ASUS RT-5300 router is.

Test 02 – Guest room with one brick wall apart

As the distance increases, combining with the fact that now there is a wall between the device and the router, you can see that the signal strength is naturally decreased. Our Pokde2.4GHz band dropped down to about -55dBm while our Pokde5G-2 dropped to about -63dBm making its strength still better than the 2.4GHz band. Don’t mind the rest of the networks. These are starting to appear from my neighbourhood. I didn’t hide them to showcase the likeliness of interference to happen on both bands too. Let me also tell you that my house is a corner lot, which means I could have doubled the number of network signals if my house was in the middle 😉

Test 03 – Play room with one brick wall and glass door

This is where things get a little more interesting. I increase the distance and now we have a glass door on top of a brick wall in between the router and the test device. Our 2.4GHz band only got a slight decrease to about -58dBm compared to Test 02. But our 5GHz band had a bigger fall, down to -71dBm. Like I mentioned earlier, different materials will have different affect on the signal strength.

Test 04 – Entrance with two solid bricks and concrete stairs

Let’s push it further. This time, looking at the layout, we have two solid brick walls and a concrete stairs in between our router and the device. Our 2.4GHz band almost didn’t felt a pinch here, sitting at -62dBm but our 5GHz band is getting a lot weaker at almost -75dBm. This is good news for me because outside of my house entrance, the 5GHz signal will disappear, making my 5GHz band only available within my premises 😉 And that’s what we will test in the next environment.

Test 05 – Furthest corner from the router

So this is the furthest corner from the router and it only goes through one single brick wall. As you can see, the results are somewhat similar to our Test 04 because now we have removed all barriers, but increased the distance.

Here’s the thing, you can see so much overlapping 2.4GHz network bands coming from all the houses around me, but not a single 5GHz band. Like I said earlier, you can either take this as an advantage for yourself (like what I think it is) or a disadvantage.

Conclusion

Nowadays, with technology advancement progressing so quickly, hardware has stepped up to support much advanced technology and one of them that many have missed out is the 5GHz wireless capabilities. I get a common question a lot and that sounds like, “Should I invest in a new router, and if yes, which one?”. The first thing that you need to identify is the speed capabilities of the router that you already have. Having a 5GHz capable router but has a slower throughput will not prove its point. I’ve jumped between one too many routers and I can very clearly tell you that getting a better router definitely has its perks and advantages. Right now, for me, the ASUS RT-5300 is the one I trust my network with. And I can only show you results to prove my point. To experience it, you will have to get one yourself 😉

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About The Author
Super Daddy
A proof that the real fun does not actually ends, but rather begins when you become a daddy. Enterprise Application Co-ordinator, Web Developer, Hardware Enthusiast, Gadgets lover, Android Evangelist, Desktop and Consoles Gamer, Metal Music Guitarist, Audiophile, Networking Freak, Radio Controlled Toys rat, Ferrari Crazy and above all - a daddy in every kid's dream.

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