Does Wi-Fi Signal Strength Affect Speed?

Long before PCs and computer networks existed, mathematician Claude Shannon and others explored the relationship between wireless signal strength and the rate at which information can be transmitted. Applied to today's Wi-Fi technology, Shannon's law or theory says the maximum speed your Internet Service Provider states can't be reached if the signal strength is not enough to overcome the amount electromagnetic interference or noise in the environment. Interference causes data errors. Errors cause network speed to slow because information has to be retransmitted repeatedly. The stronger the signal, however, the less effect noise has on data transmission speed.

Wi-Fi signal interference can come from a number of sources. Your home's electrical wiring, household appliances like microwave ovens, Bluetooth devices, cordless phones and even your cell phone can cause enough interference to slow network speed. In addition, electromagnetic interference can come from outer space. Sunspots and solar storms like coronal mass ejections may temporarily add signal-weakening noise that slows Wi-Fi speed.

The real cause of slower than expected network speed may be the distance between a Wi-Fi-enabled device and its WAP or wireless access point. Physical barriers such as walls, doors, partitions, large TVs or video displays that stand in the path of the signal may also significantly reduce signal strength or serve as source of signal interference.

There are several ways you may be able to increase network speed. You can turn off unnecessary electrical devices in the vicinity of your Wi-Fi device or your WAP. You can adjust the position of your WAP's antenna to maximize signal strength. You can also try different locations in your home or office to see where the signal strength to be strongest and where there may be sources of interference you can avoid or eliminate.