Orthogonal frequency-division multiple access
Orthogonal frequency-division multiple access (OFDMA) is a multi-user version of the popular orthogonal frequency-division multiplexing (OFDM) digital modulation scheme. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users.
Source: Wikipedia — Orthogonal frequency-division multiple access (CC BY-SA 4.0)