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Why SC-FDMA is not used for downlink?

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I know the reason why OFMDA cannot be used for the uplink but I wonder why SC-FDMA is not used for the downlink. It is still a form of OFDMA technology.

posted Jul 22, 2013 by Sonu Jindal

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1 Answer

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Best answer

OFDM takes advantage of frequency diversity to achieve higher data rates
In order to cope up with the multipass, delay-spread and inter-symbol interference associated with the Single Carrier(SC-FDMA), OFDMA symbols are made of long duration symbols and multiple sub-carriers with the data symbols made to modulate separately on diff sub-carriers, therefore it is very robust in terms of delay spread and inter-symb-interference. It is because of this virtue, it is used in the downlink, which carries demand for higher datarates.
Whereas the same thing is compromised on the uplink by using SC-FDMA because of the significant disadvantage of much higher PAPR(Peak to Avg power ratio) associated with OFDMA, causing a high battery consumption. However the Basestation is able to cope up with this as it is much more power-abundant as compared to the UE.

answer Jul 22, 2013 by Chandra Javalkar
OFDMA uses many narrow band carrier(each of 180khz) instead of single carrier(SC-FDMA) ,so it can reduce multi path fading & more efficient as comapared to SCFDMA
Similar Questions
+1 vote

PAPR is the major disadventage of OFDMA which require high resolution D/A and A/D or increasing Transmission Power.
I know that SC-FDMA used on Uplink becuase it has lower PAPR than OFDMA. On downlink direction, the high PAPR Problem of OFDMA solved by increasing eNB transmission power. This solution cannot be implemented on Uplink direction because UL is power limited link. so SC-FDMA used on UL instead of OFDMA, but why? why SC-FDMA has LOWER PAPR

+1 vote

Are the demodulation reference symbols modulated using SC-FDMA like other PUSCH symbols or using OFDM. I have seen in a couple of places that OFDM is used for the DRMS, but I cannot find anything about it in 3GPP TS 36.211.

Any pointer would be appreciated?


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