lte link budget introduction v1.0

HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

Huawei Confidential

Security Level: Internal2009-8-4

LTE Link Budget introduction

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

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=


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


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


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


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


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


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


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


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


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


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


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)


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


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


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 =


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)

lte link budget introduction v1.0

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