Number PRB
Number prb is decided by different bandwidth and SCS.
Aggregate
Aggregate relate bandwidth, no matter SCS.
ü bandwidth[60M 100]
aggregate is 2, 2^2 = 4 means that 4 AxC corresponding to one ant.
ü bandwidth[30M 50M]
aggregate is 1, 2^1 = 2 means that 2 AxC corresponding to one ant.
ü bandwidth20M
aggregate is 0, 2^0 = 1 means that 1 AxC corresponding to one ant.
FFT size
FFT size is decided by bandwidth and SCS. Sample rate= FFT_size * SCS.
FFT size @(bandwidth,SCS)show as below:
U=0 à SCS=15k
U=1 à SCS=30k
U=2 à SCS=60k
One thing need note is that for 30M, 30k, FFT size= 2048, not 1536.
Another FFT size and cp length table show as below:
cp length
Tc = Basic time unit for NR=1/(2048*15000)
Tc = Basic time unit for NR= 1/(FFT size*SCS)
K= The ratio between Ts and Tc
For example NR(100M,30k):
K=(4096*30k)/(2048*15k)=4
For example NR(100M,30k)
First symbol cp length = 144*4*2^(-1) + 16*4 = 288+64 = 352
scond symbol cp length = 144*4*2^(-1) = 288