Dft-s-ofdm vs cp-ofdm

1. What is CP-OFDM and DFT's OFDM?
2. What is Dfts OFDM?
3. Why is CP-OFDM used in 5G?
4. What is transform precoding?

What is CP-OFDM and DFT's OFDM?

The CP-OFDM waveform can be used for either single-stream and multi-stream (i.e. MIMO) transmissions, while DFT-S-OFDM based waveform is limited to single stream transmissions by targeting scenarios with limited link budget. Physical Channel Bandwidth.

What is Dfts OFDM?

The DFT-spread OFDM is a form of single-carrier technique that possesses almost all advantages of the multicarrier OFDM technique (such as high spectral efficiency, flexible bandwidth allocation, low sampling rate, and low-complexity equalization).

Why is CP-OFDM used in 5G?

CP-OFDM is used as the access technology for 5G New Radio. Its operation is very similar to that of OFDM used in LTE, however CP-OFDM features variable subcarrier spacing termed “numerology”. Where LTE uses a fixed 15kHz subcarrier separation, CP-OFDM can utilize 15kHz, 30kHz, 60kHz, 120kHz, etc.

What is transform precoding?

In term of functionality, Transform Precoding is to spread UL data in a special way to reduce PAPR(Peak-to-Average Power Ratio) of the waveform. In terms of mathematics, Transform Precoding is just a form of DFT(Digital Fourier Transform) as you see in the equation shown below.