What is modulation order in LTE? Why it is range of 0 to 8 ?

Question

why QPSK modulation scheme is used for all control channels in LTE ?

Answer 1

Hi hinmani,

Modulation order defines the modulation types used for the data transmission. Say BPSK,QPSK,QAM etc.
If lower modulation order means it is mapped to BPSK and higher modulation is 64QAM.

Comments

Hi, just to add here, let's suppose we have two UE, one UE is very close to cell and other is far, so depending on RSRP/RSRP eNB deduces that one UE is close to cell and other is far. UE is supposed to notify this capability to eNB via UE Capability Information message. If UE support 64 QAM and eNB enable UL 64 QAM, Q'm = 6 is translated to Qm = 6 (64 QAM), but if UE does not support 64 QAM and eNB does not enable UL 64 QAM, Q'm = 6 is translated to Qm = 4. So if UE uses BPSK or QPSK the modulation rate will be poor for UE compared to UE uses 64QAM