Before full commercial deployment of LTE, downlink SNR to CQI mapping for different multiple antenna techniques can be of enormous significance for the operators. Such vital RF parameters should be tuned before full-fledged commercial launch. In LTE, Adaptive Modulation and Coding (AMC) has to ensure a BLER value smaller than 10%. The SNR-to-CQI mapping is required to achieve this goal.
The CQI report not only indicates the downlink channel quality but also takes the capabilities of the UE’s receiver into account. A UE with receiver of better quality can report better CQI for the same downlink channel quality and thus can receive downlink data with higher MCS. Table I shows modulation scheme, code rate along with efficiency for various CQI index