the calculation of vswr and output power

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

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The Calculation of VSWR and Output Power


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Slide text :20-22ptBullets level 2-5:

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Some Basic Technical Details

0101ZZZZ

11VSWR

Definition of Γ

Definition of VSWR

Level 1 => go to maintenance

Level 2 => Service interrupt





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The impaction of VSWR high

• The coverage will be lower before level 2 (but still can carry traffic).

• The DDPU’s temperature get higher because of more reflect power (The reason of close TRX)

• BTS should insist working if possible.

Find a suitable threshold for level 1

Have a higher threshold for level 2





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The Calculation of Reflect Power

RIP 2

2I

R

PP





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11VSWR

121

1

VSWR

2

%

121

11

VSWR

P

2I

R

PP

2% 11

I

R

PPP

How much Power can be Transmitted Out?





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The Transmitted Power in Different VSWR

VSWRΓ=1/(1+2/(VSWR-1)) P (%) IF 60W IF 40W

1.2 0.090909 99.17% 59.50413 39.669421.5 0.2 96.00% 57.6 38.41.6 0.230769 94.67% 56.80473 37.869821.8 0.285714 91.84% 55.10204 36.734691.9 0.310345 90.37% 54.22117 36.147442 0.333333 88.89% 53.33333 35.55556

2.1 0.354839 87.41% 52.44537 34.963582.2 0.375 85.94% 51.5625 34.3752.3 0.393939 84.48% 50.68871 33.792473 0.5 75.00% 45 30

3.1 0.512195 73.77% 44.25937 29.506253.2 0.52381 72.56% 43.53741 29.02494

VSWR Calculation





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Huawei’s Advantage

• From the calculation, only little difference between VSWR 1.8 and 2.

• When the 1 level alarm generate, only 6.x W power loss.• Huawei system can still working at higher VSWR to 3!

VSWR P (%) IF 60W IF 40WDB

Deviation1.8 91.84% 55.10204 36.73469

0.142 88.89% 53.33333 35.555562.2 85.94% 51.5625 34.375

0.593 75.00% 45 30

Huawei BTS performs better service ability!





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We suggest to use the threshold 2 and 3 for the level 1 and 2 VSWR alarm.

From Huawei’s huge maintenance experience

Thank youwww.huawei.com

the calculation of vswr and output power

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