2G expansion calculations

[Kalvera]

Please share you experiance with TRX expansion strategys methodology u have used are using....

Are u taking monthly average values for TCH blocking or BH traffic and so on.


Thanks in advance,
K

PS share some useful docs if u have

[RF engineer]

dear
normally you can do as you said take one month traffic and congestion and average them . in case if you want to be more reliable take maximum of both your traffic and congestion then average on maximum.
br

[venom]

Please share you experiance with TRX expansion strategys methodology u have used are using....

Are u taking monthly average values for TCH blocking or BH traffic and so on.


Thanks in advance,
K

PS share some useful docs if u have

I always take in to account the BH traffic with also avg weekly trend.

But before making an expansion always try to balance the traffic between neighbors or use the HR, AMR etc

[Kalvera]

For the TRX offered capacity i have to calculate HR+FR capacity as well, is it correct?

I mean if i have 2 TRX offering 7.20 erl at @2% GOS, adding 2 HR licenses will increase my capacity till 20 erl??

Prompt response will be appreciated

[venom]

u can gather Double the traffic with HR !!

Try also to balance the traffic on neighbors !

[Kalvera]

So basically i have to include increased capacity in the expansion calculation, and shouldn't calculate expansion based on only FR capacity?

thanks.
K

[RF engineer]

Sure you have aslo to take HR as margin let say 50% of TRX have HR TS if you go just on full rate the amount of TRXs you need more and cost.

[Kalvera]

Gents from your experience, if i have 2 TRX with 2 HR is it gonna carry 20.15 Erlang at 2% GoS or is going to be 50% increase for 2 FR TRX i.e 2 FR can carry 7.4 Erl if it is 50 % increase so it's gonna be 14 erl?

[venom]

Gents from your experience, if i have 2 TRX with 2 HR is it gonna carry 20.15 Erlang at 2% GoS or is going to be 50% increase for 2 FR TRX i.e 2 FR can carry 7.4 Erl if it is 50 % increase so it's gonna be 14 erl?

With busy hour traffic 7.4 Erl atr 2% Blocking rate, you need 9 time slots. Two trx means u have 16 time slots available out of which 14 would be available for carrying the traffic if u r assiging 1 time slot for SDCCH traffic (traffic isnt much so u shuld go for 1 sdcch).

Now 14 time slots can carry 14.4126 Erl Traffic with FR. If you go with HR then it will be doubled 2*14.4126 = 28.825 Erl, so it should be ok if you go for HR

Thanks

[RF engineer]

Gents from your experience, if i have 2 TRX with 2 HR is it gonna carry 20.15 Erlang at 2% GoS or is going to be 50% increase for 2 FR TRX i.e 2 FR can carry 7.4 Erl if it is 50 % increase so it's gonna be 14 erl?
Dear
erlang B table is not linear function table , what i mean
let say you have two TRX and assume all TS is traffic channel then Erlang will be 9.8 erl and if come separate TRX into one TRX+one TRX will be 3.62+3.62=7.42 erl you can see the difference in traffic.
BR

[hassen]

hi kalvera

you should know the average of congestion rate in your network
wich equipment that you use E/// for example ,did you try feature cell load sharing
because it is possible to decrease congestion in BH.
if yes
according to the rate
start with reshuffling TRX in order to balance traffic

classify disadvantaged cells in the order ,i mean the worst cell attributes
Priority 1.
for example cells between 10-20 % congestion HR 100% priority 1.for this case we need trx expansion.
of course before make neighbour tune and check HO kpi
and half rate tune and check speech quality kpi

up to you !
for each network there is a single strategy for better optimization.

br hassen

[Lesmana]

u can gather Double the traffic with HR !!

Try also to balance the traffic on neighbors !


@Lccengr

Would u please tell a little more about - balance the traffic on neighbors !

Is it sharing the traffic wt neighbors by means of congestion relief?

Thanks

[basith.aces]

For the TRX offered capacity i have to calculate HR+FR capacity as well, is it correct?

I mean if i have 2 TRX offering 7.20 erl at @2% GOS, adding 2 HR licenses will increase my capacity till 20 erl??

Prompt response will be appreciated

May i know the fulform of HR and FR

please reply

[nnazzal]

With busy hour traffic 7.4 Erl atr 2% Blocking rate, you need 9 time slots. Two trx means u have 16 time slots available out of which 14 would be available for carrying the traffic if u r assiging 1 time slot for SDCCH traffic (traffic isnt much so u shuld go for 1 sdcch).

Now 14 time slots can carry 14.4126 Erl Traffic with FR. If you go with HR then it will be doubled 2*14.4126 = 28.825 Erl, so it should be ok if you go for HR

Thanks

Guys;

HR & FR principles are as in the bellow:

Assume we have 2 TRU in one cell, using Erlang-B table for the 14 TS’s with GoS=.02, it gives 8.2 Erlang not 7.2.
The HR, FR works based on the TS’s not based on the traffic, i.e. not type of multiply the traffic.

Example: in the same cell (14 TS’s) I need to open 50% HR, this means that the first 7 TS’s will stay FR, the other 7 TS’s will be HR (7*2)=14, by total I have 7+14=21 TS’s, using Erlang-B it gives 14.03 Erlang.

The maximum capacity for this cell to open all TS’s to be HR i.e. 100% half rate. This means (14 TS’s *2) =28 TS’s, using Erlang-B table it gives 21.15 Erlangs. This exactly what goes on in the FR/HR.
So, the Cell with 2 TRU’s not supporting 28Eralang without a high level of blocking.

Please if you see it’s valuable, add reputation

[venom]

Guys;

HR & FR principles are as in the bellow:

Assume we have 2 TRU in one cell, using Erlang-B table for the 14 TS’s with GoS=.02, it gives 8.2 Erlang not 7.2.
The HR, FR works based on the TS’s not based on the traffic, i.e. not type of multiply the traffic.

Example: in the same cell (14 TS’s) I need to open 50% HR, this means that the first 7 TS’s will stay FR, the other 7 TS’s will be HR (7*2)=14, by total I have 7+14=21 TS’s, using Erlang-B it gives 14.03 Erlang.

The maximum capacity for this cell to open all TS’s to be HR i.e. 100% half rate. This means (14 TS’s *2) =28 TS’s, using Erlang-B table it gives 21.15 Erlangs. This exactly what goes on in the FR/HR.
So, the Cell with 2 TRU’s not supporting 28Eralang without a high level of blocking.

Please if you see it’s valuable, add reputation

That is right, i have miscalculated it, my mistake was that i entered 20% grade of service instead of 2%. The right calculations are as follows:


With busy hour traffic 7.4 Erl atr 2% Blocking rate, you need 13 time slots. Two trx means u have 16 time slots available out of which 14 would be available for carrying the traffic if u r assiging 1 time slot for SDCCH traffic (traffic isnt much so u shuld go for 1 sdcch).

If you are using HR with full capacity then the timeslots would be doubled = 28. Which means 20.15 Erl Traffic can be carried out at full capacity (Reference Calculator Attached). But you never like to have 100% Capacity, so it is better that you look for expansion or traffic balancing between neighbors. To do traffic balancing, you need to change the HOM , Handover criterea (based on Levels or quality). In SIEMENS we use RXDLO and RXDLI


Use Erlang B calculator attached as a reference.

Thanks nnazel for correcting my calculations !!

[nnazzal]

That is right, i have miscalculated it, my mistake was that i entered 20% grade of service instead of 2%. The right calculations are as follows:


With busy hour traffic 7.4 Erl atr 2% Blocking rate, you need 13 time slots. Two trx means u have 16 time slots available out of which 14 would be available for carrying the traffic if u r assiging 1 time slot for SDCCH traffic (traffic isnt much so u shuld go for 1 sdcch).

If you are using HR with full capacity then the timeslots would be doubled = 28. Which means 20.15 Erl Traffic can be carried out at full capacity (Reference Calculator Attached). But you never like to have 100% Capacity, so it is better that you look for expansion or traffic balancing between neighbors. To do traffic balancing, you need to change the HOM , Handover criterea (based on Levels or quality). In SIEMENS we use RXDLO and RXDLI


Use Erlang B calculator attached as a reference.

Thanks nnazel for correcting my calculations !!

You are welcme, but you missed onr thing, to add me a reputation, actally i am new inthis forum and i need morereputation to download what you sent.

[Lesmana]

Dear Experts,

I'm working with ******** BTS..

Here we set HR Threshold 60%(when 60% TS occupy with FR Traffic then the remaining TS's will convert into HR).In some cells there are 4 TRX and HR is enabled in all 4 TRX.Total HR Time slots=28*2=56 and Capacity of the cell will be=45.87538706(As per erlang B Table). But the problem is:

From the stats i never saw the cell is carrying 45E traffic though the call set up blocking rate shows=10-12% during BH.Probably all TS's are not converted into HR.There also shows a significant amount of FR traffic like 4-5E.

In this situation How can i calculate the actual capacity of the cell ? Need to find the utilization.

Thanks in advance..

[RF engineer]

According to you blocking it shows that there is problem(interference or Hardware) because also FR traffic is very low 4-5 erl first solve the problem and check stat again.
BR
RF

[nnazzal]

Dear Experts,

I'm working with ******** BTS..

Here we set HR Threshold 60%(when 60% TS occupy with FR Traffic then the remaining TS's will convert into HR).In some cells there are 4 TRX and HR is enabled in all 4 TRX.Total HR Time slots=28*2=56 and Capacity of the cell will be=45.87538706(As per erlang B Table). But the problem is:

From the stats i never saw the cell is carrying 45E traffic though the call set up blocking rate shows=10-12% during BH.Probably all TS's are not converted into HR.There also shows a significant amount of FR traffic like 4-5E.

In this situation How can i calculate the actual capacity of the cell ? Need to find the utilization.

Thanks in advance..

Do you mean the SDCCH congestion is 10-12%? if you means that ,then it is normal case because of the calls destripution in the BH is not detected and you can re-dimention the SDCCH channels or you can tune the ACLC feasture, else could you explain the stats report that you use and what counters you calculate in the report, so i can help.

Thanks

[Lesmana]

Do you mean the SDCCH congestion is 10-12%? if you means that ,then it is normal case because of the calls destripution in the BH is not detected and you can re-dimention the SDCCH channels or you can tune the ACLC feasture, else could you explain the stats report that you use and what counters you calculate in the report, so i can help.

Thanks

Dear nnazzal,

Here 10-12% blocking is call setup blocking rate(TCH Blocking Rate)
and SD blocking is defined by Immediate Assignment Blocking rate in ********.

please let me know the followings if possible:

-The HR Threshold is 60%

- To calculate the capacity of a cell, do i need to calculate for both HR and FR seperately? OR It will be combined?
please see the following Questions...

1) if there are 4 TRX in a cell and total 28 Time slots for traffic.Half rate is enabled in all TRX's.For this case, how can i calculate the capacity of this cell?


AND

2) if there are 4 TRX in a cell and total 28 Time slots for traffic.Half rate is enabled in 2 TRX's. For this case, what will be the capacity of this cell?


THANKS IN ADVANCE....

[nnazzal]

Dear nnazzal,

Here 10-12% blocking is call setup blocking rate(TCH Blocking Rate)
and SD blocking is defined by Immediate Assignment Blocking rate in ********.

please let me know the followings if possible:

-The HR Threshold is 60%

- To calculate the capacity of a cell, do i need to calculate for both HR and FR seperately? OR It will be combined?
please see the following Questions...

1) if there are 4 TRX in a cell and total 28 Time slots for traffic.Half rate is enabled in all TRX's.For this case, how can i calculate the capacity of this cell?


AND

2) if there are 4 TRX in a cell and total 28 Time slots for traffic.Half rate is enabled in 2 TRX's. For this case, what will be the capacity of this cell?


THANKS IN ADVANCE....

Dear Ala'a;

First:

The HR & FR capacity should be in combined calculation since the same TS may be used as FR or may be used in HR , and to calculate the total traffic you can use the attached simple created formula (I prepare it today for your questions).

Second:

The HR is a cell parameter & not TRx parameter i.e. you can't activate the HR per TRU, it is activated for all the cell, you can't activate HR in the first 2 TRU's and leave the other TRu's.

Thanks

[imravian]

1: Stats:
Stats will be taken for the last three weeks averaged over the period in daily busy hour.

2: Criteria:
TCH congestion >=2%
TCH traffic utilization >=200%...................................................priority1
150% =<TCH traffic utilization <=200%......................................priority2
TCH congestion <2%
TCH traffic utilization >=200%...................................................priority1
170% =<TCH traffic utilization <=200%......................................priority2

TCH congestion>=2%
100% =<TCH traffic utilization <=150% and DTHNAMR>=80 ...........priority3

where traffic utilization = carried/designed traffic