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arban
2010-11-18, 04:23 PM
Can anybody confirm how many users can be connected to one Node B at one time. I know all this depends on type of service offered, you can give me breakdown in terms of service, let say CS12.2k, PS 64K, PS 384K.

THanks.:L

RF engineer
2010-11-18, 04:32 PM
Can anybody confirm how many users can be connected to one Node B at one time. I know all this depends on type of service offered, you can give me breakdown in terms of service, let say CS12.2k, PS 64K, PS 384K.

THanks.:L

Look below simple calculation

cells
UMTS Network Planning Basics!
If you have suggestions or comments email: info@umtsworld.com

UMTS Capacity Planning


The number of installed transceivers limits the mobile network theoretical capacity. In cdma systems interference, accepted and planned quality and grade of service will determine the system capacity. Cdma systems also have soft capacity, which complicates the network area capacity estimations. The link budget is used to calculate the maximum allowed path loss and the maximum range for cell. The link budget includes the interference margin, which is the increased noise level caused by greater load in a cell. So by increasing the cell load, cell coverage area becomes smaller. That's how cell coverage and capacity dimensioning are interlinked.

System capacity planning is divided to two parts:

1 The first thing is to estimate a single transceiver and site capacity. Calculations how the noise raises as the cell load increases is out of the scope of this page, but in-cell noise, Eb/No requirements, planned data rates, coverage probability, air resources usage activity factor, target interference margin and processing gains are needed to approximate the transceiver and site capacity. Depending on the parameter values, planned transceiver capacity is typically from 400 kbits/s to 700 kbits/s per transceiver.

2 The second part of the process is to estimate how many mobile users each cell can serve. Once the cell capacity and subscriber traffic profiles are known, network area base station requirements can be calculated. Estimations can be done in Erlangs per subscriber or kilobits per subscriber. Network vendor normally has simulation tools to test system parameters and verify rough estimations. A lot of data is required for comprehensive network dimensioning; number of subscribers and growth estimations, traffic / user / busy hour / geographic segment and required throughput including service mixes in geographic segments for example.

Traffic mix

Each type of traffic has to be estimated for capacity calculations.

Here is a rough downlink capacity calculation example:

During a busy hour an average user downloads 10 Mbits with 384 kbits/s, 2 Mbits with 144 kbits/s and makes one 60-second voice call. Data has to be retransmitted 1.1 times because of network conditions.

Used kbits/s per user per busy hour downlink only are:

Service Rate Average Rate
(10000 kbits / 3600 sec) x 1.1*) 3.06 kbits/s
(2000 kbits / 3600 sec) x 1.1*) 0.61 kbits/s
(60sec x 12.2 kbits/s) / 3600 sec 0.20 kbits/s
Total 3.87 kbits/s / user / busy hour

If a cell capacity is estimated to be 500 kbits/s, each cell can be dimensioned for about 129 users.
BR
RF

arban
2010-11-19, 03:05 AM
Look below simple calculation

cells
UMTS Network Planning Basics!
If you have suggestions or comments email: info@umtsworld.com

UMTS Capacity Planning


The number of installed transceivers limits the mobile network theoretical capacity. In cdma systems interference, accepted and planned quality and grade of service will determine the system capacity. Cdma systems also have soft capacity, which complicates the network area capacity estimations. The link budget is used to calculate the maximum allowed path loss and the maximum range for cell. The link budget includes the interference margin, which is the increased noise level caused by greater load in a cell. So by increasing the cell load, cell coverage area becomes smaller. That's how cell coverage and capacity dimensioning are interlinked.

System capacity planning is divided to two parts:

1 The first thing is to estimate a single transceiver and site capacity. Calculations how the noise raises as the cell load increases is out of the scope of this page, but in-cell noise, Eb/No requirements, planned data rates, coverage probability, air resources usage activity factor, target interference margin and processing gains are needed to approximate the transceiver and site capacity. Depending on the parameter values, planned transceiver capacity is typically from 400 kbits/s to 700 kbits/s per transceiver.

2 The second part of the process is to estimate how many mobile users each cell can serve. Once the cell capacity and subscriber traffic profiles are known, network area base station requirements can be calculated. Estimations can be done in Erlangs per subscriber or kilobits per subscriber. Network vendor normally has simulation tools to test system parameters and verify rough estimations. A lot of data is required for comprehensive network dimensioning; number of subscribers and growth estimations, traffic / user / busy hour / geographic segment and required throughput including service mixes in geographic segments for example.

Traffic mix

Each type of traffic has to be estimated for capacity calculations.

Here is a rough downlink capacity calculation example:

During a busy hour an average user downloads 10 Mbits with 384 kbits/s, 2 Mbits with 144 kbits/s and makes one 60-second voice call. Data has to be retransmitted 1.1 times because of network conditions.

Used kbits/s per user per busy hour downlink only are:

Service Rate Average Rate
(10000 kbits / 3600 sec) x 1.1*) 3.06 kbits/s
(2000 kbits / 3600 sec) x 1.1*) 0.61 kbits/s
(60sec x 12.2 kbits/s) / 3600 sec 0.20 kbits/s
Total 3.87 kbits/s / user / busy hour

If a cell capacity is estimated to be 500 kbits/s, each cell can be dimensioned for about 129 users.
BR
RF

Thanks RF for a good explanation on how to estimate number of users percell in node B.
You have mentioned above, that there is a cell breathing effect where the coverage of Node B will get smaller with the increment of users. May I know in what percentage the size of the radius for the cell get smaller? Thanks.:L

RF engineer
2010-11-19, 03:33 AM
Thanks RF for a good explanation on how to estimate number of users percell in node B.
You have mentioned above, that there is a cell breathing effect where the coverage of Node B will get smaller with the increment of users. May I know in what percentage the size of the radius for the cell get smaller? Thanks.:L

When the load become 50% or higher the cell breath starting to be half coverage shrinking

telecom.santosh
2011-02-14, 05:28 PM
If Maximum transceiver capacity is typically from 400 kbits/s to 700 kbits/s per transceiver then how speed reached 5mbps or more?

hngydx
2011-02-16, 03:35 AM
Thanks RF for a good explanation on how to estimate number of users percell in node B.
You have mentioned above, that there is a cell breathing effect where the coverage of Node B will get smaller with the increment of users. May I know in what percentage the size of the radius for the cell get smaller? Thanks.

RF engineer
2011-02-16, 04:24 AM
Thanks RF for a good explanation on how to estimate number of users percell in node B.
You have mentioned above, that there is a cell breathing effect where the coverage of Node B will get smaller with the increment of users. May I know in what percentage the size of the radius for the cell get smaller? Thanks.

Dear your post is not clear you copy from other collegue and paste

can i know what exactly you need. and if you ask the question i already answered.

BR

pathloss
2011-02-16, 05:44 AM
When the load become 50% or higher the cell breath starting to be half coverage shrinking

Ha, and your Answer were obviously missed! I love this..:D