MULTIPLE-ACCESS TECHNOLOGY OF CHOICE IN 3GPP LTE

Third-Generation Partnership Project (3GPP) standardizes an Evolved UMTS Terrestrial Radio Access Network (EUTRAN)as air interface in its release 8 LTE. Orthogonal Frequency Division Multiple Access(OFDMA) and Single Carrier-Frequency Division Multiple Access(SC-FDMA)are key technologies for the air interface of mobile broadband systems.It is?evident that mobile broadband access technologies are reaching a commonality in the air interface and networking?architecture; they are being converged to an IP-based network architecture with OFDMA based air interface technology.?The air interface of E-UTRAN is based on OFDMA in downlink and SC-FDMA in the uplink, making it possible to efficientl?utilize bandwidth due to the orthogonally between sub-carriers and by assigning subsets of sub-carriers to individual users?which allows for simultaneous data rate transmission from several users and differentiated quality of service for each user.?In this paper, wehighlight the technologies behindOFDMA and SC-FDMA and also carry out performance comparison of?the two air interface technologies. We brieflydescribe the 3GPP LTE standard, and its implementation using OFDMA and?SC-FDMA technology.