NB-IoT Multi-Evaluation Measurement
R&S
®
CMW-KM300/-KS300
208
User Manual 1178.5689.02 ─ 06
The 180 kHz are divided into subcarriers. There are two different modes:
●
3.75 kHz subcarrier spacing, bandwidth divided into 48 subcarriers
●
15 kHz subcarrier spacing, bandwidth divided into 12 subcarriers
In the time domain, the smallest unit is an SC-FDMA symbol. Each symbol contains a
guard time called cyclic prefix (CP). A time slot contains seven SC-FDMA symbols with
normal CP. A time slot for 3.75 kHz subcarrier spacing ends with a guard period (GP,
no UL signal).
Depending on the subcarrier spacing, the slot length is 2 ms or 0.5 ms. A radio frame
of 10 ms contains 5 slots or 20 slots.
Durations are often stated in sample intervals T
s
. T
s
can be calculated from the sam-
pling frequency 30.72 MHz: 1 T
s
= 1/30.72 MHz
≈
32.55 ns.
The following table and figures summarize this information.
Subcarriers
Slots
Symbol duration
Spacing
No.
Duration
Per frame
CP
Data
Note
3.75 kHz
48
2 ms, 61440 T
s
5
256 T
s
8192 T
s
GP at end of slot
2304 T
s
15 kHz
12
0.5 ms, 15360 T
s
20
symbol 1: 160 T
s
symbol n: 144 T
s
2048 T
s
-
Figure 3-3: Frame structure for 3.75 kHz subcarrier spacing
General Description
深圳德标仪器
135-1095-0799
