Hello Experts,
5G NR supports multiple OFDM Sub-Carrier Spacing (SCS)
15, 30, 60, 120 and 240 kHz is supported.
Why do we have extended CP only in 60 kHz?
Any reason behind this?
Extended CP is for cells with large delay spread, but don’t know why only for 60 KHz.
Hello,
Extended CP wasn’t used in LTE because 15 Khz SCS has enough Doppler resistance for the used case, so NR wanted to get rid of it. However, it can be useful in specific used case.
Big SCS = Low latency + Small coverage → Mostly used for Real time game, VR or HGH video streaming - Main SCS 120, 240 Khz.
Small SCS = Higher latency + great coverage → Mostly used for eMMB - Main SCS 15, 30 Khz.
So CP was defined for 60 Khz to be able to be used in the two used case. That’s my interpretation, but any confirmation is welcomed !
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