2.1. What is OFDM/OFDMA?
One of the key elements of Long Term Evolution (LTE) is the use of Orthogonal Frequency Division Multiplex (OFDM) as the signal bearer and the associated access schemes, OFDMA (Orthogonal Frequency Division Multiplex Access) and Single Carrier Frequency Division Multiple Access (SC-FDMA).
OFDM is a modulation format that is very suitable for carrying high data rates – one of the key requirements for LTE.
OFDM can be used in both frequency division duplex (FDD) and time division duplex (TDD) formats, and LTE operates in both FDD and TDD modes.
Therefore, LTE is an OFDMA-based technology standardized in 3rd Generation Partnership Project (3GPP) release 8 and the following releases 9, 10, 11 and 12 to date.
OFDMA stands for Orthogonal Frequency Division Multiplex Access. It is based on OFDM, a coding scheme invented in Centre Commun d’etudes en telecommunications et television (CCETT, Rennes, France) in 1982. The purpose of OFDM was, at that time, focused on digital television transmission. OFDM and OFDMA are two different variants of the same broadband wireless air interface that are often mistaken for one another. OFDMA is a form of OFDM, which is the underlying technology.
OFDM is a superior air access, which has been chosen for LTE and now adopted by most radio communication systems, such as WiMax and Wi-Fi. OFDM is the coding scheme of all digital television systems, especially terrestrial (DVB-T and DVB-T2) and satellite (DVB-S2) broadcasting ...