Orthogonal Frequency Division Multiple Access (OFDMA) is a multiple access scheme for OFDM systems. It works by assigning a subset of subcarriers to individual users.

OFDMA features

  • OFDMA is the 'multi-user' version of OFDM

  • Functions by partitioning the resources in the time-frequency space, by assigning units along the OFDM signal index and OFDM sub-carrier index

  • Each OFDMA user transmits symbols using sub-carriers that remain orthogonal to those of other users

  • More than one sub-carrier can be assigned to one user to support high rate applications

  • Allows simultaneous transmission from several users ⇒ better spectral efficiency

  • Multiuser interference is introduced if there is frequency synchronization error

The term 'OFDMA' is claimed to be a registered trademark by Runcom Technologies Ltd., with various other claimants to the underlying technologies through patents.