Orthogonal frequency division multiple access is the process of dividing a radio carrier channel into several independent sub-carrier channels that are shared between simultaneous users of the radio carrier. When a mobile radio communicates with an OFDMA system, it is dynamically assigned a specific sub-carrier channel or group of sub-carrier channels within the radio carrier. By allowing several users to use different sub-carrier channels, OFDMA systems increase their ability to serve multiple users and the OFDMA system may dynamically allocate varying amounts of transmission bandwidth based on how many sub-carrier channels have been assigned to each user.
As demonstrated in Figure 1, the WiMAX system allows more than one simultaneous user per radio channel through the use of orthogonal frequency division multiple access (OFDMA). The WiMAX radio channel can be divided into multiple sub-carriers and that the sub-carriers can be dynamically assigned to multiple users who are sharing a radio carrier signal. Finally, the data rates that are provided to each user can vary based on the number of subcarriers that are assigned to each user.
