ANALISIS RTWP (RECEIVED TOTAL WIDEBAND POWER) PADA JARINGAN GSM

Assalamualaikum..

halo sobat jagaad, gimana kabarnya?..semoga selalu mendapat barokah yach..

kali ini ane mau share masalah RTWP. gara-garanya ane add trx pada dcs..eh masih ada blocking dan ternyata tak cek ada alarm RTWP/RSSI unbalanced yang artinya tuh ada masalah pada RTWP. lha ini yang bikin ane kudu analisa lagi..kenapa gaes? bisa faktor software bisa dari faktor hardware..ini kan karena adanya interferense..bisa disebabkan dari luar atau dari bts itu sendiri..

RTWP yang baik itu sekitar..-104.5 sampai -105.5..kalau kurang jelek kalau lebih juga jelek..tetapi kalau RTWP itu sudah jauh dari idealnya apalagi sampai 1000 wah ini mesti hardware nih..udah parah..karena RTWP itu sendiri dihitung berdasar sinya output dan juga gainnya..

DAFTAR SINGKATAN
2G =Second Generation Technology
3G =Third Generation Technology
3GPP =The 3rd Generation Partnership Project
AMPS = Advanced Mobile Phone System
AUC= Authentication Center
BER= Bit Error Rate
BSC= Base Station Controller
BTS= Base Transceiver Station
CDMA= Code Division Multiple Access
CEPT=Conference Europeance d’Administration de Post et Telecommunication
 CME= Civil Mechanical Electrical
CN= Core Network
CSSR= Call Setup Success Rate
DCS= Digital Cellular System
DECT= Digital Enhanced Cordless Telecommunications
EDGE= Enhanced Data Rates for GSM Evolution
ETSI= European Telecommunication Standard Institute
FCC= Federal Communication Commission
FLM= First Level Maintenance
GGSN= Gateway GPRS Support Node
GMSC= Gateway MSC
GPRS= General Packet Radio Service
GPS= Global Positioning System
GSM= Global System for Mobile Communication
HC= Handover Control
HLR= Home Location Register
HSCSD= High-Speed Circuit-Switched Data
HSDPA= High Speed Downlink Packet Access
IBC= In-Building Coverage
IMT-2000= International Mobile Telecommunications-2000
ITU= International Telecommunication Union
K3=Keselamatan dan Kesehatan Kerja

LAN= Local Area Network
LMT= Local Maintenance Terminal
MDF= Main Distribution Frame
ME= Mobile Equipment
MS= Managed Service
MSC= Mobile Services Switching Center 

NF= Noise Figure
NMT= Nordic Mobile Telephony
NOC= Network Operation Center
PC= Power Control
PDH= Plesiochronous Digital Hierarchy
PHS= Personal Handy-phone System
PIC= Person In Charge
PSTN= Public Switched Telephone Network
QoS= Quality of Service
R99= Release99
RF= Radio Frequency
RNC= Radio Network Controller
RNS= Radio Network System
RSSI= Received Signal Strength Indicator
RTO= Request Timed Out
RTWP= Received Total Wideband Power
SDH= Synchronous Digital Hierarchy
SGSN= Serving GPRS Support Node
SLA= Standard Level Agreement
SMS= Short Message Service
SOC= Service Operation Center
TACS= Total Access Communication System
TMA= Tower Mounted Amplifier
TOC= Trunk Operation Center
TT= Trouble Ticket
UE= User Equipment
UMTS= Universal Mobile Telecommunication Service
USIM= UMTS Subscriber Identity Module
UTRAN= UMTS Terrestrial Radio Access Network
VLR= Visitor Location Register
WARC= World Administrative Radio Conference
W-CDMA= Wideband-Code Division Multiple Access
WiMAX= Worldwide Interoperability for Microwave Access
WLAN= Wireless LAN

terus kalau untuk teori RTWP..sekali-kali ane copas yang bahasa inggris lah biar gayeng..halah..

If you work with UMTS,'ve probably heard someone talk about RTWP. Its definition can be found in a dictionary of acronyms, such as http://acronyms.thefreedictionary.com/RTWP: Received Total Wideband Power.

Represents a measure of UMTS technology: the total level of noise within the UMTS frequency band of any cell.

RTWP is related to uplink interference, and its monitoring helps control the call drops - mainly CS. It also has importance in the capacity management, as it provides information for the Congestion Control regarding Uplink Interference.

In UMTS, the uplink interference may vary due to several factors, such as the number of users in the cell, the Service, Connection Types and Conditions of Radio, etc..

As our goal is to always be as simple as possible, we will not delve in terms of formulas or concepts involved. We will then know the typical values, and know what must be done in case of problems.

Typical Values

Ok, we know that RTWP can help us in checking the uplink interference, then we need to know its typical values.

In a network is not loaded, normal, acceptable RTWP Average value is generally around -104.5 and -105.5 dBm.

Values around -95 dBm indicate that the cell has some uplink interferers.

If the value is around -85 dBm, the situation is ugly, with strong uplink interferers.

Usually we have High, Low and Medium measures of RTWP. However, the maximum and minimum values are recommended only as auxiliary or reference, since they may have been caused by a peak of access, or even been forced to have a momentary value due to some algorithm i.e..

Thus, the value that helps us, and has the most accurate information is the same Mean RTWP!

For cases in which cell has two carriers, the difference between them RTWP should not exceed 6 dB.

Based on these typical values, most vendors have an alarm: RTWP "Very High. "

What to do in case of problems?

We have seen that RTWP can cause performance degradation, mainly CS Call Drops. Note: Actually, it's not RTWP that causes performance degradation. What happens is that when its value is 'bad', it's actually indicating the presence of interference - the latter being responsible for degradation.

But what can we do when we find bad values?

If RTWP is not at acceptable levels, some actions should be taken.

• The first thing to do is check if there is a configuration issue with the RNC or NodeB. This is the most common case, especially in cases of new activations.
• Once verified the parameter settings, the next step is the physical examination, especially jumpers and cables, often partially reversed. It also should be checked if there is faulty transmitters, or any other problem that could generate intermodulation between the NodeB and the antenna.
• If the parameter settings and hardware are ok, the chance is very high that we have external interference, such as a Interferer Repeater.

In cases where there may be external interference, we must begin to act after such a prioritization based on how much this is affecting the cell KPI's across the network, if it carry high traffic, major subscribers, etc..

Note: There are many forms of interference in the uplink, both internal and external. Only a few are listed above. The deepening of all possibilities is beyond the goal of being simple to teach the concepts, but this is a suggestion for whoever wants to deepen the study, identification and elimination of interference.

In practice

to find - and eliminate - problems of interference is one of the biggest challenges in our area. For being such a complex problem, we recommend that be collected enough data for each investigation. Insufficient data collected can lead to erroneous conclusions, further worsening the problem.

The uplink interference may appear only in specific periods. Thus, it is recommended that data be collected from at least one week (7 days) for every 24 hours. Usually this amount of data is sufficient. In the figure below, we see different days and times - colorful - a fictional example where the interference occurred.

Data should be collected for the suspicious cell, but also for its adjacent cells, allowing it to make a triangulation increasing the chances of locating the source of interference.

Another way to locate the source of interference is to do a test in field. An antenna guy must gradually change the azimuth of the antenna, while another professional do RTWP measurements. That is, through the information directing the antenna and the respective values of RTWP, you can draw conclusions very good.

It is obvious that changing the online system may not be a good practice, and tests can be made with a Yagi antenna and a Spectrum Analyzer.

Vendors offer several ways to measure RTWP, using the OSS, performance counters and logs.

Conclusion

In this brief tutorial, we learn what is RTWP, and that the ideal typical value is about -104.5 dBm and -105.5 dBm.

As the RTWP is directly related to Uplink Interference - and we know that interference is the main cause of performance degradation - have concluded that improving RTWP, ie making is as close as possible to -105 dBm, improving the Call Drop Rate!

IMPORTANT : Seizing the opportunity, see what was stated at the start of this tutorial - dictionary - by describing RTWP. Remember that this site has been the subject of a very interesting tutorial in the Tips Section. If you have not visited this section of the portal yet , I strongly recommend, because it has many issues that help in our growth in telecom and IT area.

http://www.telecomhall.com/what-is-rtwp.aspx

https://www.scribd.com/doc/123867240/Laporan-Praktik-Kerja-Lapangan-Analisis-RTWP-pada-Jaringan-3G-AXIS-Menggunakan-Perangkat-Lunak-LMT

jadi intinya begini kalau bingung :

kita liat record RTWPnya..

- kalau jam tertentu terutama jam sibuk maka berarti ada interferesi dari luar. kalau itu masalahnya berarti bisa mengarah antena atau power dikurangi agar tidak saling berebutan..

- kalau alarmnya ada terus dan tidak tentu jamnya berarti ada masalah dari bts itu sendiri..

caranya :

cek databasenya apakah ada setingan power atau yang lain yang tidak sesuai dengan perangkat atau plannya.

jika database udah sesuai. cek hardware..apakah vswrnya..bisa dicek dengan dsp vswr..kalau normal berarti perlu dicek on site..

masalah yang terjadi disini feeder belum terpasang sempurna..jadi onsite diberin semua dikencengin serta dicek kkonctor dan kabelnya..

disini sajalah..

semoga bermanfaat..

alhamdulillah