Tech Sense: Wireless By John Bell
Updated: Nov 2, 2021
This month our topic is wireless technologies. We will try to briefly cover three wireless technologies that we find in our pockets, our homes, and nearly everyplace we go. These are NFC, Bluetooth, and Wi-Fi.
Near Field Communications (NFC)
Most phones today have a feature called NFC which is primarily used to make payments using your mobile phone. NFC stands for Near Field Communications. NFC is very short-range allowing the signal to reach nearly 3 inches from the phone. Yes, that is 3 inches. This is why when you make a purchase using the phone you nearly tap the device to the phone. The short distance makes the protocols less susceptible to being hacked. In addition to payment terminals, NFC is sometimes used to exchange data between phones, read biological sensors, open hotel doors, and send images to printers. NFC is best to transmit small amounts of data like the information on a credit card or business card.
Nearly all modern phones and most new laptop computers have built-in support for Bluetooth. The primary use for Bluetooth is to connect to add-on devices like headsets and mice. A Bluetooth signal can travel about 33 feet between transmitter and receiver. Bluetooth beacons are Bluetooth devices that transmit a small bit of information to your phone. An app on the phone can then track where you are located by knowing which beacons you are near. Bluetooth tags are also useful for finding lost items. The tag is attached to an item that you don’t want to lose. Whenever the tag is near a phone with a supporting app (Apple phones have this tracking built-in to iOS) the app will report where it was when it communicated with the tag. This information is then transmitted to your phone using mobile networks.
Wi-Fi is the wireless technology most commonly used to access the Internet. Wi-Fi supports several different wireless bands each supporting different amounts of data and different distances the signals can travel. The older Wi-Fi 4 over the 2.4 GHz radio band can travel 300 feet outdoors, but more typically is limited to 150 feet indoors. Wi-Fi 4 signals support between 72 and 600 Mbits/s. Wi-Fi 5 and 6 using the 5 GHz band has a shorter range (about1 third the distance) but higher bandwidths over 9000 Mbits/s.
In most homes Wi-Fi is provided by a wireless router. The router connects to the Internet provider through a cable modem (Comcast/Xfinity) or an Optical Network Terminal (ONT) (Verizon). The router has an Access Point (AP) built-in which broadcasts the wireless signal. Wireless devices like computers and phones then connect to this signal to access the Internet. Most new routers support both 2.4GHz and 5GHz signals giving a choice of longer distance or faster speeds. Also, because the 5GHz signal doesn’t travel as far it is less likely to interfere with other neighboring routers.
In larger homes the Wi-Fi signal may not cover the entire house. In this case additional access points or repeaters can be used to make the signal available over a larger area.
The Wi-Fi standards have changed significantly over the years. Today, the newest devices are using the Wi-Fi 6 standards are based on IEEE 802.11ax standards that were adopted in 2019. These standards give the highest wireless speeds (over 9000Mbits/s) but need to be supported both on the router and the devices using the wireless signals. Older slower devices are still supported on these routers but can’t benefit from the higher performance. Wi-Fi 5 based on IEEE 802.11ac was adopted in 2014 and at 6000Mbits/s is still fast enough from most home users. For many homes with Internet access under 250 Mbits/s, Wi-Fi 4 routers based on IEEE 802.11n and supporting up to 600 Mbits/s is fine. Remember that if your Internet connection is only 200 Mbits/s a faster router can’t make the Internet connection any faster no matter what the TV commercials imply.