Signal Bars: How Accurate Are They Really?

It all starts with something called the common pilot channel, or CPICH. Used in UMTS and other CMDA communication networks, the pilot channel is a downlink channel broadcast by Node Bs that has constant power and a known bit sequence. Steve van Skike, Senior Manager of Test and Regulatory for Nextivity told Digital Trends:

You can characterize the waveform – the signal coming from an operator, whether it’s LTE or UMTS – by a pilot channel that’s always transmitted, which is a constant. The traffic loading goes up and down depending on how many people are using the network.Steven van Skike

Each cell phone manufacturer uses different algorithms to calculate how many signal bars should show up on your phone.

There’s no standard. They do indicate signal strength, but it’s up to the handset manufacturer to come up with whatever algorithm they want. They certainly want to do something that is appropriate for the consumer, it needs to be meaningful information, but the details are up to them.Steven van Skike

When a cell phone is connected to data, it reports signal strength that it sees back up to the network, and the network then tries to make a smart choice about what technology, band or channel the phone will use for its user’s next communication.

For example, if you’re in a crowded place like a club, you might get pushed onto a different wireless band if for no other reason that your phone supports it. So even if you’re connected to the same network as the people around you, that doesn’t mean you’ll have the same number of signal bars on your phone.

But the real question is: Do more bars mean a better signal?

Almost always, yes. There are cases where you can have interference or capacity problems and you may have plenty of signal bars, but it doesn’t mean that the service is reliable at all. But for the most part these things work the way they’re supposed to, and more bars should mean better service.Steven van Skike

Steve also explains the difference between how iPhones and Android phones calculate signal strength:

iPhone products stood out because you could put an Android phone next to an iPhone and decrease the signal-to-noise ratio on purpose, while keeping the input signal level constant, and you’d see the bars decrease. So we knew right away that they had a more complicated algorithm when determining the number of bars.Steven van Skike

There’s a lot of excitement as Google is rumored to release it’s MVNO, codenamed Project Fi today. One of the features to look forward to is having phones switch more easily between networks, depending on which one is stronger in your area. Also rumored is seamlessly switching your calls between WiFi and data. Since there is no standard when it comes to signal bars and algorithms, maybe Google can push carriers to come up with a standard.

Signal Bars: How Accurate Are They Really?

Source: Digital Trends Website On Signal Bars

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Andrew Orr