I am wondering would router wifi signal strength drop significantly when large number of users connecting onto it? Or is there any possible problems could arise when there is a sudden surge of large volume of people trying to connect to a single router?
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It called an access point, AP, not router. There is an inverse relationship between wireless client throughput and the number of client devices concurrently transmitting and receiving traffic trough the AP. Coverage planning and Capacity planning are distinct and equally important.– Ronnie SmithCommented Jul 17, 2016 at 2:06
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Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.– Ron Maupin ♦Commented Aug 14, 2017 at 4:06
3 Answers
The medium for wireless communication is air/space which is limited. There is only so much of it. The more clients connecting the more medium is used less medium there is for others. The signal strength would not really be compromised. The signal strength depends on the room parameters (humidity, type of walls, other radio frequencies in operation). There is a limited amout of clients that can connect. The limit is generally bound to the specs of the access point, but in essence would be limited to the amount of available bandwidth/space in the air within that given frequency. So I think to answer your question, the more users connecting to an access point the less performance in general you can expect, this resulting because of shared bandwidth/medium (space). Signal strength is more of a constant, how far that signal gets or how many clients your access point can serve is based on other factors.
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@SIRO1969 In addition to the excellent post by Max, also take into account the most commonly used enterprise hardware for wireless transmission atm is only half-duplex. If you have many users watching videos, doing torrents, etc. for only one wireless access point... contention for air time is in play and the users experience degrades. There are recommended solutions for your wireless infrastructure to match these challenges, search the web for "High Density Wireless Design"– user4565Commented May 18, 2016 at 20:43
A starting point is that signal strength really isn't the issue, it's the signal-to-noise ratio. A wi-fi radio is listening to one transmission at a time. If energy from another transmission comes in it can make the decoding the initial reception more difficult. The ability to decode is based upon SNR and not the received power.
To make it possible for a radio to receive only one signal at a time, wi-fi uses something called collision avoidance (which is much different than wired ethernet's collision detect) so there is only one transmission to an AP's radio (or, more preciesly, a receiver's radio) at a time. (Note: APs these days have multiple radios so they can support things like 2.4G and 5G simultaneously and some have more) The avoidance techniques cause a bottleneck per distributed access to a shared medium, which is roughly 10K transmissions opportunities (TXOPs) per second at a peak. As more devices come in these TXOPs will be consumed.
Optimal avoidance techniques depend upon hearing peer transmissions in order not to clobber them. For wi-fi, there can be hidden nodes, i.e. two devices can hear the AP but not each other hence the potential to "interfere" with a current reception. In this case, a transmission can require more TXOPs so the AP can effectively reserve air time for the devices which can't hear one another.
So there is a performance impact of a sudden surge of devices but it's mostly due to the need to arbitrate for the AP's "ear." A way around this is to weaken the signal (cell coverage) and add more APs creating more cells, effectively increasing the number of simultaneous conversations that can be supported by the network.
In my experience the signal strength shouldn't change only the speed. When more devices/users connect to the router you will start to see a performance decrease in terms of Internet speed because all the devices will be sharing the same Internet connection at the same time.