Why isn't Aggregation Level dynamically indicated?


Anyone know why Aggregation Levels are not dynamically indicated rather than allowing UE to blindly find it?

Aggregation level basically is the number of CCEs used for carrying a DCI to a UE. DCI is such important information that UE is expected to decode without any issue even at the cell edge/high interference conditions. If UE fails to decode the DCI, it fails to decode the PDSCH/fails to send PUSCH. By keeping the design to allow blind decodes by UE with multiple aggregation levels, we are giving freedom to the network to use multiple aggregation levels when sending DCI without any explicit RRC signaling. If UE is at the cell edge/high interference, a higher aggregation level is used → more number of RBs for carrying the DCI → high channel coding → higher chance of decoding the DCI. If UE is near to the cell, a low aggregation level is sufficient. Network can dynamically shift between the aggregation levels based on the path loss and interference conditions.