1 emlab wireless propagations. 2 emlab channel rf dsp 데이터 송신 rf dsp 수신 데이터 1....
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![Page 1: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/1.jpg)
1
EMLAB
Wireless propagations
![Page 2: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/2.jpg)
2
EMLAB
channelRFDSP데이터
송신
RF DSP
수신
데이터
1. Wireless channel model
• 무선 통신 기기 사이의 전파 송수신 예측 어려움 .
• 단말기 설계를 위해 channel 특성 파악 필요 .
![Page 3: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/3.jpg)
3
EMLAB
근사 모델 #1: Free space model
2
4
RGGPP RTTR
R
Rc
j
RT eR
GGH
4)(
(Friis formula)
• 거리 감쇄 효과만 고려 .
• 초기 설계에 유용 .
![Page 4: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/4.jpg)
4
EMLAB
Antenna modeling
)/(4
cRtR
R
)ˆˆ(),(4 hT,vT, TT
jkR
TTTT
in hhR
eG
P
E
안테나에서 나온 신호는 거리 R 떨어진 지점에서 진폭이 1/R로 줄어들고 시간 지연이 R/c 만큼 생긴다 .
)(t
![Page 5: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/5.jpg)
5
EMLAB
Field test route (outdoor)
Guidelines for drive testing to accurately estimate average cell radius or for tun-ing a path loss model.
![Page 6: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/6.jpg)
6
EMLAB
Field test route (indoor)
Typical in-building measurement route and signal strength.
![Page 7: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/7.jpg)
7
EMLAB
Measured path loss
![Page 8: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/8.jpg)
8
EMLAB
Physical model
Impu
lse
resp
onse
Time
dthstxt
R )()()(
)(th
Measurement Simplified model
![Page 9: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/9.jpg)
9
EMLAB
Propagation channel model
tfjtfjii
iiR
cic eettstx 2)(2)]([)(Re
Impu
lse
resp
onse
Time
Spec
tru
m
Frequency
Amplitude variation
time spread
Mathematical model
αi(t), τi(t) 가 channel 특성 결정 .
![Page 10: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/10.jpg)
10
EMLAB
Hierarchical fading process : statistical model
![Page 11: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/11.jpg)
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EMLAB
Propagation loss mechanisms : scaled model
1. Large Scale Fading:due to distance
2. Medium Scale Fading: shadowing and obstacles
3. Small Scale Fad-ing: due to multipath
![Page 12: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/12.jpg)
12
EMLAB
The three scales of mobile signal variation
![Page 13: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/13.jpg)
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EMLAB
(1) Large scale fading
)/()(][)( 00 dddPLdBdPL
( 거리와 path loss 를 fitting 하여 β 값을 찾음 .)
![Page 14: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/14.jpg)
14
EMLAB
근사 모델 #2 : Two-ray Ground Reflection
21
21
4)(
R
eR
R
eGGH
Rc
j
S
Rc
j
RT
![Page 15: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/15.jpg)
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EMLAB
• Measure PL(d0) or calculate Free Space Path Loss.
• Take measurements and derive empirically.
근사 모델 #3 : Log-Distance Model
Environment Exponent (β)
Free space 2
Urban area 2.7~3.5
Shadowed urban area 3~5
Indoor LOS 1.6~1.8
Indoor non-LOS 4~6
)/()(][)( 00 dddPLdBdPL
![Page 16: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/16.jpg)
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EMLAB
Classification of large scale propagation models1. Macro cell model
① Empirical model
a. Log-distance path loss
b. Okumura-Hata
② Physical model
a. COST231/Walfisch-Ikegami Model
③ ITU-R model
2. Micro cell model
④ Empirical model
a. Dual slope model
⑤ Physical model
a. Two-ray model
b. Street canyon model
c. Random waveguide model
d. Ray tracing model
⑥ ITU-R model
3. Pico cell model
⑦ Empirical model
⑧ Physical model
![Page 17: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/17.jpg)
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EMLAB
Okumura-Hata model (COST207)
1. 150MHz~1.5GHz 에서 유용 .
2. 측정을 통해 얻은 데이터임 .
3. Open area, Suburban area, Urban area 로 분류함 .
ERBALdB log
CRBALdB log
DRBALdB log
1.1)56.0log56.1()7.0log1.1(
3001.1))54.1(log(29.8
30097.4))75.11(log(2.3
94.40log33.18)(log78.4
4.5))28/(log(*2
log55.69.44
log82.13log16.2655.69
2
2
2
2
CmC
Cm
Cm
CC
C
b
bC
fhfE
MHzfh
MHzfhE
ffD
fC
hB
hfA
For large cities
For medium to small cities
frequencycarrier :[MHz]f
mobile andstation base
between distance circlegreat :R[km]
1.5m) (oftemheight
antennastation mobile:][
C
mhm
Urban areas :
Suburban areas :
Open areas :
![Page 18: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/18.jpg)
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EMLAB
COST231-Hata model
GERBFLdB log
areasan metropolit3
areassuburban and cities sized medium0
log82.13log9.333.46
G
hfF bC
1. 1.5GHz~2GHz 로 Hata 모델 확장
2. 측정을 통해 얻은 데이터임 .
3. Open area, Suburban area, Urban area 로 분류함 .
![Page 19: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/19.jpg)
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EMLAB
Walfisch-Ikegami Propagation Model
sdmsdFdB LLLL Lf : free space loss
Lmsd:multiple knife edge diffraction
Lsd : single diffraction
![Page 20: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/20.jpg)
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EMLAB
(2) Medium scale model : shadowing
SdB LLL 50
![Page 21: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/21.jpg)
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EMLAB
Typical variation of shadowing with mobile position at fixed BS distance
Probability density function of shad-owing. Measured values are pro-duced by subtracting the empirical model.
Log-normal distribution : shadowing
2
2
2exp
2
1)(
S
S
L
S
LLp
![Page 22: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/22.jpg)
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EMLAB
LzxSz SS
zQdx
xdLLpzL
L /
2
2exp
2
1)(Pr
Shadowing effect on coverage
![Page 23: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/23.jpg)
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EMLAB
(3) Small scale fading
tfjc
cetuttftats 2)(Re)(2cos)()(
)()()()( )( tjytxetatu tj
Probability density function of real part of NLOS fading signal→ Gaussian
Multi-path fading : NLOS
![Page 24: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/24.jpg)
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EMLAB
Equal delay ellipse : multi-path fading
![Page 25: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/25.jpg)
25
EMLAB
Complex samples of NLOS fading signal Theoretical and experimental Rayleigh distributions
Rayleigh fading
![Page 26: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/26.jpg)
26
EMLAB
Rician fading
2
2 2/
s
P
Pk
NLOS
LOS
kr
Ieer
rp kr 2)( 0
)2/(2
22
Rice factor :
![Page 27: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/27.jpg)
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EMLAB
c
,1
12
)cos1()( υk
][ || tυrrr
c
kυ
kkk ||
][|| HυEEE
][|| EυHHH
HE,
HE ,k
υ
동일한 전자기 현상이지만 관찰자의 상대적 운동에 의해 E, H, k, 주파수 등이 변한다
2c
ttrυ
Frequency shift by Doppler effect
![Page 28: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/28.jpg)
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EMLAB
1f
2f
Beat frequency due to Doppler effect
)cos1( ff
υ
다중 경로 신호의 주파수가 달라져 beat frequency 관찰됨 .
![Page 29: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/29.jpg)
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EMLAB
The received signal of a time varying channel where the transmitted signal is a time-harmonic signal with frequency f =10Hz.
Time varying channel – Doppler shift
Dc f
T16
9
![Page 30: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/30.jpg)
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EMLAB
Time varying channel : auto-correlation
Power spectral density
)2()()( 0* Dlll fJPtataE
otherwise0
if)/(1
2
)2()( 20
D
DDD
ffffffJFfS
( fD : maximum Doppler frequency.)
( )S F
Dff
Jakes model
For time delay profile
Dc f
T16
9Coherence time :
![Page 31: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/31.jpg)
31
EMLAB
Wideband fast fading
c
rr 21
]1[
)()(])([
1
])([2
])([1
11
2211
jtj
tjtj
eea
eaeaH
)]cos(1[2)( 1 aH
![Page 32: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/32.jpg)
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EMLAB
Multi-path Fading
Impu
lse
resp
onse
Time
• Flat fading :
• low data rate.
• Ex) AMPS, ASK, ...
Time
Impu
lse
resp
onse
Sd T
• Frequency selective fading :
• high data rate 인 경우에 생김 .
• Ex) WCDMA, DMB 등 ...
Sd TInter-symbol interference
ST
STSymbol Time
d
d
![Page 33: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/33.jpg)
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EMLAB
Multi-path Fading
Multi-path Fading 의 영향
•협대역 신호인 경우 영향이 작다 .
광대역 신호인 경우 신호 spec-trum 에 미치는 영향이 크다 .
![Page 34: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/34.jpg)
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EMLAB
l
tffjll
llcetxtaty ))((2)()(Re)(
…shift in time …
…shift in frequency …
… attenuation…
(this causes small scale time variations)
paths
Wide-band fast fading channel model
![Page 35: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/35.jpg)
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EMLAB
Channel sounding
n
iii
T
PP
10
n
iii
Trms P
P20
21
rmscB 2
3
Coherent B. W. :
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36
EMLAB
Overcoming narrow band fading
Diversity
![Page 37: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/37.jpg)
37
EMLAB
Overcoming wide band fading
Linear equalizer
![Page 38: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/38.jpg)
38
EMLAB
Adaptive equalizer
![Page 39: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/39.jpg)
39
EMLAB
OFDM receivers
OFDM Subcarriers in the Frequency Domain
![Page 40: 1 EMLAB Wireless propagations. 2 EMLAB channel RF DSP 데이터 송신 RF DSP 수신 데이터 1. Wireless channel model 무선 통신 기기 사이의 전파 송수신 예측 어려움](https://reader036.vdocuments.mx/reader036/viewer/2022062515/56649f3e5503460f94c5e43e/html5/thumbnails/40.jpg)
40
EMLAB
. . .
0w 1w 2Nw 1Nw
12
각도 추정
.
.
.0w 1w 2Nw 1Nw
RF, modem
다중 빔 안테나
각도 추정 알고리즘 다중 빔 생성
Adaptive antenna