Single carrier FDMA for uplink wireless transmission

While LTE’s downlink uses OFDM, the uplink uses a different modulation scheme known as single-carrier frequency-division multiplexing (SC-FDMA) . OFDM signals have a high peak to average power ratio (PAPR), requiring a linear power amplifier with overall low efficiency.

The performance of SC-FDMA in relation to OFDMA has been the subject of various studies. Although the performance gap is small, SC-FDMA’s advantage of low PAPR makes it desirable for uplink wireless transmission in mobile communication systems, where transmitter power efficiency is of paramount importance .

OFDMA is used on the downling, but since it presents a high Peak-to-average Power Ratio it is not possible to use it on the uplink . For the uplink SC-FDMA will be used.