Radiocommunication

Radiocommunication is the transmission of information through radio waves to enable communication between distant points. It covers a wide range of systems, including broadcasting, two-way voice and data links, mobile networks, satellite communications, radar, and navigation services. The signals travel through unguided electromagnetic energy in the radio spectrum, typically from about 3 kHz to 300 GHz.

A radiocommunication system consists of a transmitter that generates and modulates a signal onto a carrier wave, an antenna that radiates the radio wave, and a receiver with an antenna that captures the signal and demodulates it to recover the information. Propagation of radio waves depends on frequency and environment, with line-of-sight limiting higher-frequency links, ground waves operating at lower frequencies, and skywave or ionospheric propagation enabling long-range communication under certain conditions. Atmospheric factors such as weather and multipath can affect signal quality.

Modulation is the method used to encode information onto the carrier. Analog modulation includes amplitude, frequency, and phase modulation, while digital modulation uses schemes such as PSK, QAM, and OFDM, often combined with error-correcting codes and multiplexing techniques like FDMA, TDMA, and CDMA. Bandwidth, power, and coding determine system capacity and resilience, and multiple channels can be carried within a single spectral band through multiplexing.

Applications of radiocommunication include broadcast radio and television, cellular and mobile data networks, satellite links, radar, Wi-Fi and Bluetooth, and navigation systems such as GPS. Spectrum management and standards are governed by national regulators and international bodies, notably the ITU, which coordinate frequency allocations, licensing, and interference mitigation to ensure reliable operation across services.