The
LTE uplink transmission scheme for FDD and TDD mode is based on SC-FDMA (Single
Carrier Frequency Division Multiple Access).
This
is to compensate for a drawback with normal OFDM, which has a very high Peak to
Average Power Ratio (PAPR). High PAPR requires expensive and inefficient power
amplifiers with high requirements on linearity, which increases the cost of the
terminal and also drains the battery faster.
SC-FDMA
solves this problem by grouping together the resource blocks in such a way that
reduces the need for linearity, and so power consumption, in the power
amplifier. A low PAPR also improves coverage and the cell-edge performance.
Still, SC-FDMA signal processing has some
similarities with OFDMA signal processing, so parameterization of downlink and
uplink can be harmonized.