Contents
- 1 Why SC-FDMA is single carrier?
- 2 What is the advantage of using single carrier frequency division multiple access SC-FDMA in the uplink?
- 3 Why we are using SC-FDMA in LTE uplink instead of OFDMA?
- 4 Which is better TDMA or FDMA?
- 5 What is the advantage of using SC-FDMA in the LTE uplink?
- 6 Which is better TDM or FDM?
Why SC-FDMA is single carrier?
SC-FDMA (Singe Carrier FDMA) presents the benefit of a single carrier multiplexing of having a lower Peak-to-average Power Ratio. On SC-FDMA before applying the IFFT the symbols are pre coded by a DFT (Discrete Fourier Transform). This way each subcarrier after de IFFT will contain part of each symbol.
What is the advantage of using single carrier frequency division multiple access SC-FDMA in the uplink?
Owing to its inherent single carrier structure, a prominent advantage of SC-FDMA over OFDM and OFDMA is that its transmit signal has a lower peak-to-average power ratio (PAPR), resulting in relaxed design parameters in the transmit path of a subscriber unit.
Why we are using SC-FDMA in LTE uplink instead of OFDMA?
SC-FDMA is preferred for LTE uplink mainly due to its advantage of having low peak-to-average power ratio (PAPR) during signal transmission. It is found that by increasing spreading factor symbol error rate is reduced for SC-FDMA system and for spreading factor of 64 for SNR=20 dB, SER is of the order of 10 -4 .
What is difference between FDM and TDM?
FDM is the multiplexing technique which is used in analog system. In FDM, Guard band is required and the spectral efficiency of FDM is low….Frequency Division Multiplexing (FDM):
| S.NO | TDM | FDM |
|---|---|---|
| 2. | TDM works with digital signals as well as analog signals. | While FDM works with only analog signals. |
How OFDM is better compare to FDM?
It is also the multiplexing technique which is used in analog system. In OFDM, Guard band is not required and the spectral efficiency of OFDM is high which oppose to the FDM….Orthogonal Frequency Division Multiplexing (OFDM):
| S.NO | FDM | OFDM |
|---|---|---|
| 7. | FDM supports low data rate. | While OFDM gives higher data rate. |
Which is better TDMA or FDMA?
FDMA is the channelization protocol in which bandwidth is divided into various frequency bands….Difference between FDMA and TDMA :
| Sr. No. | FDMA | TDMA |
|---|---|---|
| 6. | It requires stability of high carrier efficiency. | It does not require stability of high carrier efficiency. |
| 7. | It is basically used in GSM and PDC. | It is basically used in advanced mobile phone systems. |
What is the advantage of using SC-FDMA in the LTE uplink?
SC- FDMA has a lower PAPR and lower sensitivity to carrier frequency errors while OFDMA provides better frequency diversity resulting in better immunity against multipath fading.
Which is better TDM or FDM?
FDM is the multiplexing technique which is used in analog system. In FDM, Guard band is required and the spectral efficiency of FDM is low….Frequency Division Multiplexing (FDM):
| S.NO | TDM | FDM |
|---|---|---|
| 5. | TDM is efficient. | While it is inefficient. |