Wireless Data Communication

Wireless data communication carries digital information between devices using radio waves instead of cables. The data, a stream of bits, is impressed on a radio carrier through digital modulation and transmitted through the air to a receiver that recovers the original bits. Because radio is a shared medium, wireless systems include techniques to let many devices coexist without interfering with one another, and to keep the link reliable in the presence of noise and reflections.

Bluetooth is a short-range wireless standard designed to connect personal devices over distances of a few metres, replacing cables between items such as headphones, keyboards and phones. It uses a technique called frequency hopping, in which the transmitter rapidly changes the carrier frequency in a predetermined sequence many times per second. Hopping spreads the signal across many channels, which reduces the effect of interference on any single frequency and makes the link more robust.

Wireless LAN (WLAN), widely known by the Wi-Fi name, connects computers and other devices to a network and to the internet over ranges of tens of metres, typically within a home or office. It operates in unlicensed radio bands and uses access points that bridge wireless devices to a wired network. Both Bluetooth and Wi-Fi operate in shared, unlicensed frequency bands, so they must tolerate interference from each other and from other equipment. They achieve this through a combination of spread-spectrum methods, error detection and protocols that retransmit data that arrives corrupted.

Frequently asked questions

What is frequency hopping and why does Bluetooth use it?

Frequency hopping rapidly changes the carrier frequency in a set sequence, spreading the signal over many channels so interference on any one frequency has little effect, which makes the link more robust.

How do Bluetooth and Wi-Fi differ?

Bluetooth links personal devices over a few metres to replace cables, while Wi-Fi connects devices to a network over larger areas such as a home or office.

How do wireless systems cope with interference?

They use spread-spectrum techniques, error detection and protocols that retransmit corrupted data, allowing reliable communication in shared, unlicensed radio bands.