Wi-Fi engineers have been led to believe, and-for better or worse-site survey software validates the belief that data rates can be reliably predicted based on a metric like RSSI or SNR. Though often ignored, rate adaptation is a critical component of any high-performance system. When it’s tuned properly, a good adaptation algorithm finds the right data rate that delivers peak AP output in current RF conditions –unstable as they are. Rate adaptation is the function that determines how and when to dynamically change to a new data rate. How do I get more reliable Wi-Fi?įinding the right balance between optimum performance and reliability with adaptive data rate algorithms is what separates the great Wi-Fi systems from those that are good enough. There have been many examples of poor rate control algorithms loose in the wild (in both popular AP's and common client devices) that do not actually achieve this monotonic performance, especially when subject to unexpected environmental inputs or certain radio degradations. The physical layer data rate selection algorithm is critical to achieving the monotonically increasing relationship shown here up to saturation. Variability in the environment and in the radios themselves makes real-world wireless throughput a random variable that can only be assessed accurately via statistical methods. All of the details (especially the scale) of this graph are highly dependent on the capabilities of the transmitting radio, the receiving radio and the environment. In fact, at some point (usually a few cm away from the AP) you can eventually run into a signal strength so high that the receiver's front-end is unable to process it, at which point throughput will drop precipitously. (One gross oversimplification is to think of different MCS as being somewhat like different gears on a bike or car.) Once there is sufficient signal strength to operate reliably in the maximum supported MCS rate, additional signal strength does not produce additional throughput gains. The super detailed, professional and technical diagram below shows a typical relationship for any modern wireless system with adaptive modulation: The data transfer speed increases up to a point as signal strength increases since higher signal strengths enable the use of higher PHY (PHYsical layer data) rates, also known as MCS (Modulation and Coding Scheme) in modern Wi-Fi. How does Wi-Fi signal strength relate to data transfer speed?Īll other factors (of which there are many) being equal, stronger signal strength is correlated with higher data transfer speeds, with a couple of exceptions and assuming an optimal physical layer data rate selection algorithm. So here's a good, fairly simple explanation from one of our rocket-scientist founders, Bill Kish, that should help clarify things. The answer, like all answers to WI-Fi questions, can be difficult to get a grip on. One question we constantly get is this: Does a stronger Wi-fi signal always imply faster webpage loading and downloads? The relationship between Wi-Fi signal strength and the speed at which data can be transferred over that signal is something that is essential to understand when it comes to Wi-Fi performance.
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