CMW500 LTE射频测试简介
罗德与施瓦茨产品支持部
学习内容
通过本次学习,我们将了解到
LTE物理层的结构是怎样的
LTE功率分布有什么特点
TS 36.521定义了哪一些测试
Jun 2011 | LTE Test| 马志聪, RS_SZ 2
LTE物理层
物理层资源示意图
slotT
DL
symbN
N
DL
symb N
×
RB
sc
lk
),(
s
r
e
i
r
r
a
c
b
u
s
c
s
B
R
N
×
L
B
D
R
N
s
r
e
i
r
r
a
c
b
u
s
c
s
B
R
N
0=l
= Nl
DL
symb
1
Jun 2011 | LTE Test| 马志聪, RS_SZ 3
LTE物理层
LTE时频资源
RE(Reosurce Element), LTE最小的资源
REG(RE Group), 将4个RE组合在一起,作为更大的粒度
RB(Resource Block), 12subcarrier*1slot,是LTE基本调度单元
RB Pair,在一个TTI中两个时间上连续的,频率相同的RB
Jun 2011 | LTE Test| 马志聪, RS_SZ 4
LTE物理层
LTE物理层帧结构(FDD)
TCP
5.1/4.7 us
CP
TSYMBOL 66.73s
f0 f1 f2
1/TSYMBOL=15kHz
f0
f1
f2
f
1
2
3
4
5
6
7
CP
OFDM
Symbol
CP
OFDM
Symbol
CP
OFDM
Symbol
CP
OFDM
Symbol
CP
OFDM
Symbol
CP
OFDM
Symbol
TCP
16.7 us
1 subframe = 2
slot, 1slot = 0.5ms
slot slot
Normal CP
Extended CP
1 subframe = 1ms
(= min TTI)
#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19
1 radio frame = 10 subframes = 10 TTIs = 10 ms
Jun 2011 | LTE Test| 马志聪, RS_SZ 5
LTE物理层
物理层帧结构 – Type 1(FDD)
1 frame = 10 ms
1 frame = 10 subframe
1 subframe = 2 slot(0.5ms)
Maximum FFT size (20 MHz Bandwidth) = 2048(110x12=1320 subcarrier used)
Subcarrier spacing = 15 kHz
Subcarrier Bandwidth 2048x15kHz = 30.72 MHz
Jun 2011 | LTE Test| 马志聪, RS_SZ 6
LTE物理层
物理层帧结构 – Type 2(TDD)
One radio frame = 10 ms = 2 half-frames
Subframes 0 and 5 always for DL
Special subframe with various partitioning of the following 3 fields
DwPTS – DL
GP – Guard period
UpPTS – UL, always followed by an UL subframe
Diagram illustrates 5 ms DL to UL switching point periodicity
One special subframe per half-frame
10 ms switching point periodicity also supported
One special subframe per radio frame
Supports 7 different UL/DL configurations
Different numbers of UL / DL subframes partitioning
Jun 2011 | LTE Test| 马志聪, RS_SZ 7
LTE物理层
TYPE2 UL/DL 配置
这个时间间隔表示两个相邻特殊子帧的时间间隔
Jun 2011 | LTE Test| 马志聪, RS_SZ 8