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faares
2011-11-21, 02:37 PM
Dear all ,

I have observed in our network that the coverage of some site in remote area(villages) getting reduced ,after commission and configuration
of new sites it performs very nicely with a coverage of 25km and some times more then after couple of months it reaches
only 15km at most.can any one tells what are the factors that effecting the reduction in network coverage.

Thanks

jan74
2011-11-21, 09:48 PM
Dear all ,

I have observed in our network that the coverage of some site in remote area(villages) getting reduced ,after commission and configuration
of new sites it performs very nicely with a coverage of 25km and some times more then after couple of months it reaches
only 15km at most.can any one tells what are the factors that effecting the reduction in network coverage.

Thanks

That doesnt sound normal at all unless you have changed parameters such as Cell Radius or CPICH...

faares
2011-11-21, 10:17 PM
but as the customers complains they were getting a good coverage and all over sudden it shrink and it is in many sites in the villages.
so kindly help in this issue, notice: the BTS is of HUAWEI vendor and no alarm at all.
what will be the factor that is causing the shrinking of coverage.

jan74
2011-11-21, 10:49 PM
but as the customers complains they were getting a good coverage and all over sudden it shrink and it is in many sites in the villages.
so kindly help in this issue, notice: the BTS is of HUAWEI vendor and no alarm at all.
what will be the factor that is causing the shrinking of coverage.

Have you got drive test measurements before and after? You cant believe a customer when they say coverage is an issue as they dont know. You might have capacity or pilot pollution issues. Possibly cell shrinkage but not by 10km!

jayk
2011-11-22, 05:52 AM
but as the customers complains they were getting a good coverage and all over sudden it shrink and it is in many sites in the villages.
so kindly help in this issue, notice: the BTS is of HUAWEI vendor and no alarm at all.
what will be the factor that is causing the shrinking of coverage.

TRX Addition using Combiners reduces output power; that can reduce coverage or someone have put Downtilt on your antennas or output power has been reduced by parameters.. check for these things.

faares
2011-11-22, 01:09 PM
Have you got drive test measurements before and after? You cant believe a customer when they say coverage is an issue as they dont know. You might have capacity or pilot pollution issues. Possibly cell shrinkage but not by 10km!
Thanks for your reply,could you please elaborate more on how the capacity will effect the coverage.
thanks

faares
2011-11-22, 01:13 PM
TRX Addition using Combiners reduces output power; that can reduce coverage or someone have put Downtilt on your antennas or output power has been reduced by parameters.. check for these things.
Thanks for you reply, Combiner loss you mean the CDU , DDPU or you mean the TX combination configration like wideband combining.

jayk
2011-11-22, 01:54 PM
Thanks for you reply, Combiner loss you mean the CDU , DDPU or you mean the TX combination configration like wideband combining.

Your query is related to 2G or 3G? Points mentioned by me applies on GSM system...

faares
2011-11-22, 02:51 PM
2G system Hauwei vendor

rfoptman
2011-11-22, 04:13 PM
If you just decide on customer complaint without DT in field, then you can check "RX Lev Access Minimum" in the cells or penalty offsets values.

srilasitha
2011-11-22, 04:53 PM
This is a common Issue and there can be many causes. You may have one or many
Common causes
1. Configuration changes
Software changes such as TRX power, RACH min, RX level min
hardware changes: Capacity expansion, antenna adjustments

2. Hardware issues
faulty DDPU/DRFU,feeder issues, connector issues, antenna issues

3. New sites commissioning by other vendors

this will affect the customers who is having poor signal strengths

faares
2011-11-22, 05:32 PM
This is a common Issue and there can be many causes. You may have one or many
Common causes
1. Configuration changes
Software changes such as TRX power, RACH min, RX level min
hardware changes: Capacity expansion, antenna adjustments

2. Hardware issues
faulty DDPU/DRFU,feeder issues, connector issues, antenna issues

3. New sites commissioning by other vendors

this will affect the customers who is having poor signal strengths
thanks for ur reply , can we say the Feeder swap in a cell will affect the coverage if yes , then how ?
thanks

jan74
2011-11-22, 05:40 PM
Thanks for your reply,could you please elaborate more on how the capacity will effect the coverage.
thanks

I am not saying capacity affects the coverage. I am saying that you may not have a coverage problem apart from possible issues at cell edge with more noise if there is a lot of traffic, giving the impression to your customers of a coverage problem. The best thing is to compare pre and post drive tests.

jayk
2011-11-23, 05:06 AM
thanks for ur reply , can we say the Feeder swap in a cell will affect the coverage if yes , then how ?
thanks

feeder swap can cause UE not to camp on best cell, due to missing neighbors. So it can be taken as low coverage in areas. Feeder swap effects more on Rx Quality and causes high call drops.

srilasitha
2011-11-24, 03:05 PM
thanks for ur reply , can we say the Feeder swap in a cell will affect the coverage if yes , then how ?
thanks
Feeder swap can happen between sectors or within the same sector.

For example sector A feeders A+, A-, Sector B feeders B+,B-

there could be several combinations possible.....:( Of course these things we have experienced when checking problem site feeder tracing.
For A and B feeder combinations ..........Issues are obvious and need no explanations.

Antenna ports are TX/RX and RX. therefore + and - feeder crossing will slightly reduce coverage.
Sector antenna swap can cause coverage issues as the neighbor cell definitions and measurement frequencies are not matching actual requirements

melkaiy
2011-11-24, 07:17 PM
faares,
dude I think you better check the RTWP, if the RTWP is too high then it is interfered externally. External interference may reduce the coverage radius especially the signal quality. You can hear in the dt software if there are intra-freq handover in gsm. If there are, then we know that intra-freq ho has been occurred which is actually a ho between same freq and in gsm this is means interference. It handed over to the same frequency. You can also check if there are a lot of subscribers using the network. This is the cell breathing phenomenon wherein the as more and more subscribers use the system the cell shrinks (more and more capacity, the cell shrinks). Not actually the coverages radius but the good quality. Rxqual good range has been decreased then you better check the CE congestion if some overload is already happening.

I hope this one helps kindly add reps if you like this :)

faares
2011-11-25, 12:02 AM
Feeder swap can happen between sectors or within the same sector.

For example sector A feeders A+, A-, Sector B feeders B+,B-

there could be several combinations possible.....:( Of course these things we have experienced when checking problem site feeder tracing.
For A and B feeder combinations ..........Issues are obvious and need no explanations.

Antenna ports are TX/RX and RX. therefore + and - feeder crossing will slightly reduce coverage.
Sector antenna swap can cause coverage issues as the neighbor cell definitions and measurement frequencies are not matching actual requirements
Thanks , but in huawei BTSs in the DDPU you will find it has two ports labeled with A and B and on the antenna will find + and -, so which one is TX/RX port and RX port in this example as well your example.

jayk
2011-11-25, 02:19 PM
both ports of antenna are tx/rx. there is no difference if you connect A & B to + or -. Swap is considered when one feeder or both feeders are swapped with other sectors..

justdream
2012-03-16, 12:25 AM
Dear, what's your BTS Type?
Have you noticed Coverage reuction after modifying configuration for all BTS types? or specific type?

maq17
2012-03-18, 11:44 AM
Dear Faares

2G RRU Huawei uses one (two) amplifier(s) for a certain number of TRX. For example, if you have an initial configuration of 3 TRX in that sector, you could have a maximum of 20Watts per TRX, but if you increased capacity to 6TRXs, you would have 10Watts per TRX, so it could impact the coverage

25Km cell range is not a close distance for a regular BTS, so you must check capacity expansion very carefully. Also you can ask your O&M team for support related to power per TRX distribution, VSWR or RRU alarms or maybe they can check in site if some kind of failure with no alarm occured (for example, a new obstruction like a tower or building or an unanthorized change of azimut or tilt)

sad_RNP
2012-03-23, 02:46 PM
Thanks , but in huawei BTSs in the DDPU you will find it has two ports labeled with A and B and on the antenna will find + and -, so which one is TX/RX port and RX port in this example as well your example.

pls find the attach file content Check TRX Output Power guidbook

25717

sad_RNP
2012-03-23, 02:51 PM
[QUOTE=sad_RNP;174163]pls find the attach file content How to find wrong TCH jumpers (feeders) connection

pls find the attach file content How to find wrong TCH jumpers (feeders) connection

tito_rober87
2012-03-30, 07:45 AM
Hi sad_RNP,

I see your post about how to find wrong TCH jumpers (feeders) connection, but i am new in this web, please could you send me this file, its very important for me.

Thanks in advance
BR.

peanut
2012-03-30, 08:41 AM
Dear,

Did you check your PathBalance (DL Losses - Ul Losses) statistics on the BCCH TRX, in the case of PathBalance <= -10, there is a lot of DL losses so your coverage will shrink.

Ragards,

ayodeji
2012-07-25, 04:54 AM
every interesting topic to learn from specially those working in telecom industry.kindly keep the topic alive.

ayodeji
2012-07-25, 05:03 AM
Hi sad_RNP,

I see your post about how to find wrong TCH jumpers (feeders) connection, but i am new in this web, please could you send me this file, its very important for me and my career.
Thanks