HUAWEI TECHNOLOGIES CO., LTD.
www.huawei.com
Huawei Confidential
Security Level: Internal2009-8-4
LTE Link Budget introduction
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LTE Link budget process Start
Assume an uplink/downlink load
Calculate uplinkCell radius
Calculate downlinkCell radius
Min (uplink, downlink)
Effective cell radius
End
Input Data
No
Yes
AdjustCell uplink/downlink load
Calculate site number
R
R 2389 RArea=
2323 RArea=
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Downlink: Radio Link BudgeteNodeB Transmit Power (e.g. 46dBm)
NodeB Antenna Gain
UE Antenna Gain
Other Gain Slow fading margin
Interference margin
Body Loss
Cable Loss
Penetration Loss
Path Loss
DOWNLINK BUDGET
UE reception sensitivity(e.g. -109dBm)
Antenna Gain
Other Gain
Margin
Loss
Path Loss
CableLoss
AntennaGain
NodeBSensitivity Penetration
Loss
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Uplink: Radio Link Budget
Path Loss
CableLoss
AntennaGain
NodeBSensitivity Penetration
Loss
UE Transmit Power(e.g. 23dBm)
UE Antenna Gain
Node B Antenna Gain
Other Gain Slow fading margin
Interference margin
Body Loss
Cable Loss
Penetration Loss
Path Loss
UPLINK BUDGET
eNodeB reception sensitivity(e.g. -119dBm)
Antenna Gain
Other Gain
Margin
Loss
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Cable Loss in Link BudgetCable Loss in Link Budget includes:
--- Cables loss between NodeB and antenna
--- Jumper Loss between NodeB and antenna
--- Connectors loss between NodeB and antenna
Cab
le L
oss
Cable loss = cable length(m)/100 * cable loss per100m(dB) + Jumper loss + connector loss
Manufacturer Type SizeInsertion loss/100m
800MHz 2100MHz 2500MHz
Andrew
LDF4 1/2" 6.456 10.961 12.09
FSJ4 1/2" 10.431 18.137 20.11
AVA5 7/8" 3.325 5.678 6.27
AL5 7/8" 3.676 6.246 6.89
LDP6 5/4" 2.465 4.342 4.828
AL7 13/8" 2.193 3.798 4.208
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Path loss & Propagation Model
Stanford A/B/C Model Band:2.5/3.5/5.8GHz, Antenna height 10~80mCell radius <10km, suburban scenario
Cost231-Hata Model Band: 1500~2000MHz , antenna height 30~200mCell radius 1~20km
Cost231-WI Model Band: 800~2000MHz , Antenna height 4~50mCell radius 0.02~0.5km
Okumura-Hata Model Band: 150~1000MHz , Antenna height 30~200mCell radius 1~20km
SPM Model All band after calibration
MorphologyPenetration Loss (dB)
2600M 2100M 900M
Dense Urban 20 19 18
Urban 17 16 16
Sub Urban 13 12 12
Rural Area 8 8 8
Available Propagation Model
Typical penetration lossBody Loss
Data service 0dBVoice service 3dB
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Path Loss and Fading Margin
Path Loss— fading due to propagation distance
Short term (fast) fading — slight (ignored in LTE)
Long term (slow) fading — caused by shadowing
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Slow Fading MarginSlow Fading --- Signal levels obey Log-Normal distribution
Slow Fading Margin depends on:--- Area Coverage Probability
--- The higher coverage probability is, the more SFM required--- Standard Deviation
--- The higher standard deviation is, the more SFM required
Received Signal Level [dBm]
Prob
abilit
y D
ensi
ty
Fmedian (x)Fthreshold
Coverage Probability:
P COVERAGE (x) = P [ F(x) > Fthreshold ]
Coverage Probability:
P COVERAGE (x) = P [ F(x) > Fthreshold ]σSFM required
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Service Rate (Down Link) - traffic bear (e.g. Bit Rate 64kbps)
Relationship between service rate and MCS & RB
BitRate_DL (Kbps) = (1-BLER)*(168-36-12)*(code bits)*(code rate)*Nrb*CC=2, if 2T2R-MCW (MIMO option, detail in page16)C=1, if others.
12 (sub-carriers) * 7 RE * 2 (Slot) =168 REControl Signal = 36 REReference Signal = 12 RE
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Service Rate (Up link) - traffic bear (e.g. Bit Rate 64kbps)
Relationship between service rate and MCS & RB
BitRate_UL(kbps) = (1-BLER)*(168-24-0) *(code bits)*(code rate)*Nrb
12 (sub-carriers) * 7 RE * 2 (Slot) =168 REControl Signal = 24 RE
1RB=84RE, 1 Sub frame contains 168 RE
Nrb: Number of RB (Resource Block),
12
7
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Es/No (1/2) -SINR RequiredEs/No Definition
It is the Signal-to-Interference-and-Noise-Ratio as experienced by the detector.
Impact factors
1.Radio Environment (e.g. ETU3)2.Frequency Band (e.g. 2600MHz)3.MCS4.RB(Resource Block) number5.BLER(e.g. 10%)
Es/No is the most important parameter in link budget, primarily determined by MCS & RB
Multi-Path Channel Model
ETU3 Urban 3km/h
ETU30 Urban 30km/h
ETU60 Urban 60km/h
EVA30 Vehicle 30km/h
RA3 Rural 3km/h
RA120 Rural 120km/h
HT250 Hill 250km/h
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Es/No (2/2) -MCS & RB
Modulation Code bits code rateQPSK 1/3 2 1/3
QPSK 1/2 2 1/2
QPSK 3/4 2 3/4
16QAM 1/2 4 1/2
16QAM 3/4 4 3/4
64QAM 1/2 6 1/2
64QAM 2/3 6 2/3
64QAM 3/4 6 3/4
64QAM 5/6 6 5/6
Es/No is primarily determined by MCS & RB (simulation result from RTT department)
Es/No =
Bandwidth (MHz)
Total Number of RB(Nrb)
1.4 6
3 15
5 25
10 50
15 75
20 100
MCS= Code bits * Code rate Total available RB
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Other Gain
N
NodeB
Multi-elementTransmitter
M
MS
Multi-elementReceiver
MIMOMIMO::Multiple Input Multiple OutputMultiple Input Multiple Output
HARQ Gain (dB) 1.5
VoIP Bundling Gain (dB)
4.5(Uplink only)
IRC Gain (dB) 0.8(QPSK only)
Other FactorsOther Factors
MIMO gain is reflected by different Es/No (SINR)
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Other Gain- MIMO
Down Link Up Link1T1R 1T1R
2T2R-SFBC 1T2R 2T2R-MCW
2T2R-MCW 1T2R 2T2R-MCW
1T2R 1T1R
MIMOMIMO::Multiple Input Multiple OutputMultiple Input Multiple Output
DL option -> UL option
SFBC: Space Frequency Block Code
MCW: Multiple Code Word
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Reception Sensitivity
Rx Sensitivity Composite (Final Result)
Thermal noise : -174dBm/Hz
NF ( Noise Figure of eNodeB ): 2.1dB for 2.6G 1.6dB for others
Rx Sensitivity Per Sub-carrier
= Thermal noise (dBm/Hz)+ 10*lg(sub-carrier band)+ NF + Es/No
= Rx Sensitivity Per Sub-carrier +10lg(Sub carrier Number)
NF ( Noise Figure of UE ): 7dB
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Typical Interference Margin
Interference MarginMore Load Larger Noise Rise More Interference Margin
Up Link Load Interference Margin (dB)Low(~30%) ~3
High(~100%) ~6
Down Link Load level depends on the Noise Rise
NoTotal PINoiseRise =
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Differences between LTE and WCDMA
LTE
Hard handover
No fast fading margin
Composite Rx sensitivity
Small cell radius for voice (For the
same frequency)
WCDMA
Soft handover
Fast fading margin
Single service Rx sensitivity
Large cell radius for voice (For
the same frequency)
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