What are the disadvantages of SC-FDMA?

Question

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?

Answer 1

SC-FDMA is a FDMA with single carrier and is used in the UL of LTE to counter the problem of PAPR (Peal to average power ratio) in OFDMA and obviously has low resource utilization as compare to OFDMA. Other then this following disadvantages of FDMA are still applicable to SC-FDMA.

• In the FDMA technique,it is impossible for the stations to receive data from more than one transmission source.
• One of most important thing in communication systems is the maximum data rate which is small and fixed for every channel in FDMA.
• Because of the guard bands,the capacity of the FDMA will be decreased.
• Increasing the cost of FDMA,since the band filters are narrow that can't be recognized by VLSI.
• FDMA requires special filters to avoid any interference between the narrow channels.