CCE is the smallest resource unit for PDCCH transmission. Which of the following descriptions about CCE are correct? (Multiple choice)
A . When the channel condition is good, the system message will use the PDCCH of 1CC
C . PDCCH with aggregation level 1 with the highest code rate and the worst demodulation performance
D . PDCCH with aggregation level of 8 with the lowest code rate and best demodulation performance
E . eNodelB can be 1, 2, 4, 8 CCEs polymerized together to form a PDCCH
Answer: BCD