A method of radio transmission that allows a large number of users to share access to a group of radio frequency channels without interference by assigning specific frequencies within the group of frequencies to each user.

A multiple access technology that separates users by putting each traffic channel on a discrete frequency band.

A method of enabling several communications devices to use the same transmission channel by allocating a portion of the capacity of the channel on a pair-by-pair basis using frequency division multiplexing (FDM).