# cellular communication

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#### sundarmeenakshi

##### Full Member level 3
erlang traffic intensity charts

hi friends
any body know ? how do use erlong B chart.

#### ubna

The erlang B chart is used to find the Traffic intensity in a system with specified no. of channels that has to meet given probability of blocking. Cellular network providers use it to determine the maximum traffic intensity their system can support. It is also used to find the no. of channels required when establishing a system that should meet specified traffic and grade of service

### sundarmeenakshi

points: 2

#### A.Anand Srinivasan

erlang chart is just like any other chart and using it you can find the average traffic intensity of a system given its number of channels and its GOS...

### sundarmeenakshi

points: 2

#### sundarmeenakshi

##### Full Member level 3
A.Anand Srinivasan said:
erlang chart is just like any other chart and using it you can find the average traffic intensity of a system given its number of channels and its GOS...
IT IS OK HOW TO USE THE CHART.
IN RAPPAPORT SOME PROPLEM IS GIVEN BUT I AM NOT GETTING PROPER RELATION.
BUT TABLE I GOT EXACT VALUES

#### ubna

Can you clearly say which problem and what is the difficulty you encountered..

### sundarmeenakshi

points: 2

#### sundarmeenakshi

##### Full Member level 3
ubna said:
Can you clearly say which problem and what is the difficulty you encountered..
c=1,Au-0.1,GOS=0.005.

THEN THAY ARE SAYING FRM FIG A=0.005

LIKE THAT SAYING HOW IT IS?
IN FIG X-AXIZ IS TRAFFIC INTENSITY IN ERLANG
Y-AXIS IS PROBABILITY OF BLOCKING
INSIDE SOME LINE S ARE GIVEN.

I DON'T HOW TO USE THIS CHART.

#### A.Anand Srinivasan

the blocking probability is given in the y axis and it is the GOS... now search for the line C=1 and find what value of A it gives when GOS=0.005 that is all... this is the value of A you have to find...

now divide A by Au to find the number of users....

### sundarmeenakshi

points: 2

#### ubna

Actually in the Rappaport the graph for A<0.1 is missing. For your given data you need to follow the curve c=1 and find where it crosses the horizontal dotted lines for the given GOS.The curve c=1 is not fully given there..

### sundarmeenakshi

points: 2

#### sundarmeenakshi

##### Full Member level 3
ubna said:
Actually in the Rappaport the graph for A<0.1 is missing. For your given data you need to follow the curve c=1 and find where it crosses the horizontal dotted lines for the given GOS.The curve c=1 is not fully given there..
YES
IT IS NOT PROPER.

SUPPOSE GOS=0.02,C=20 THE VALUE OF TAFFIC INTENSITY IS 10 ERLANG IT IS CORRECT?

#### ubna

No. I think its 10.5
You need to follow c=20 and stop where it crosses the gos=0.02 and then stop at that point and see the vertical dotted line at that point and determine the traffic intensity

points: 2