We review the most common commercial technologies for wireless communications. This includes radio frequency, optical, acoustical and other methods for moving information / data from one location to another. The best thing about these technologies is that none of them require cables or other physical connections between the transmitter and the receiver.
ISM (Industrial, Scientific, Medical) – this is an “unlicensed” spectrum, utilizing frequencies from 915 MHz to 5.800 GHz. Within the ISM band is where our most common radio frequency technologies (Bluetooth, Wi-Fi, ZigBee, etc.) operate and co-exist.
Bluetooth – designed to replace cables between cell phones, laptops, and other computing and communication devices within a 10-meter range.
Wi-Fi (Wireless Fidelity) – designed and optimized for Local Area Networks (LAN); it provides an extension or replacement of wired networks for dozens of computing devices within a +100-meter range. This encompasses all forms of wireless Ethernet with data rates typically in the 10 Mbps up to 10 Gbps, and a range of +25-meters.
For more comprehensive information on Wireless technologies with an emphasis on Bluetooth and WiFi, take a look at this text (about $30) from Amazon by Gordon Colbach, Wireless Networking: Introduction to Bluetooth and WiFi .
Li-Fi (Light Fidelity) – Visible Light Communications (VLC) system using LED light bulbs, effective within a +50-meter range.
Under ideal conditions, data rates of 224 Gigabits per second (Gbps). For real world conditions and configurations with multiple transmitters in the same space, speeds are more typically around 70 Megabits per second (Mbps).
Read more in: The Secret of LiFi or download the free Kindle Unlimited e-book “How to Design Your Own Li-Fi Dongle for audio and music applications : play your audio signals through light”
ZigBee – a standard enabling control and monitoring capabilities for industrial and residential applications within a +100-meter range, at frequency of with 915 MHz or 2.4 GHz. It has a very low data rate, with a maximum of 250kbps. It’s primarily used for low-power / battery nodes.
IrDA (Infrared Data Association) – short range (< 1 meter), line-of-sight communication standard for exchange of data over infrared light (e.g., optical communications). IrDA interfaces are frequently used in computers and mobile phones. Data rates are from 2.4 kbps to 1 Gbps
RFID (Radio Frequency Identification) – automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags. An RFID tag is a small object that can be attached to or incorporated into a product. Most common examples are Carpool Lane Transponders, Parking Garage Passes, Silicone Wristbands, and Security Tags.
This technology generally operates in the 13.56 MHz, 860 to 930 MHz and 2.45 GHz frequency ranges, with a distance of +30-meters. Data rates can be high, but for short bursts only. This is acceptable since usually only a small amount of information (e.g., 64kbits) is stored in a target device.
For More Information – You can read more about this topic in a companion article – Common Types of Wireless Communications – An Introduction.