Download - GSM Performance KPI Optmization

GSM Performance KPI & Optmization - AdvancedModule 1 : Day 1

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© Ericsson AB 2009 | Ericsson Internal | X (X) | Date

INDEX

› Objectives› OSS Performance Management › RN Counters and KPIs› Circuited Switched KPI– Accessibility– Retainability– Integrity– Inter System Operability– Traffic

› GPRS KPI in BSS– General GRPS KPI– GPRS Best Effort Service KPIs

› Optimization using OSS


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Objectives

› Introduction to OSS Performance Management- Explain the collection and storage process for performance statistics.

› Introduce GRAN counters and associated KPI formulas (voice and data)- Explain the various RN counter types used in GRAN- Use CPI to find BSC and RBS counter description- Explain how RN counters fit into call scenario flow chart.- Use CPI to find GRAN KPI formulas

› Explain and show optimization tasks done on OSS


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OSS Performance Management


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Network Statistics (NWS)

NWS supports the following Network Elements (NE):

› AXE based network elements › Mobile Media Gateway network elements like

M-MGW, XC and Sgw nodes. › Wireless Packet Platform (WPP) based

GPRS Support Node (GSN) network elements

› Juniper based Gateway GPRS Support Node (GGSN) and IP network elements.

› WCDMA RAN network elements, Radio Network Controller (RNC), Radio Base Station (RBS) , and RXI

NWS is the OSS-RC Performance Management application.


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NWS Components

1. Initiation and CollectionSMIA –AXEMIA – MGW, IMS, GSN…SGW – all abovePDM (SPDM) – JuniperPMS – WCDMA RAN

2. Storage (Statistical Data Mart)sdm - SDM Commonsdmb - SDM GRANsdmc – SDM Core & GPRS

3. Presentation and AnalysisPSA (Performance Statistical Alarms)NWS-A (Network Statistic Analyzer) NWS-AG, GSM NWS-AC, Core NWS-AP, GPRS NWS-AM, Mobile Positioning


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Initiation of Measurements

SMIA supports the following types of job categories: › All Object Types in Statistics and Traffic Measurement (STS) subsystem. › Traffic Measurement on Routes (TRAR) in OMS. › Traffic Measurement on Traffic Types (TRART) in OMS › Traffic Dispersion Measurement (TRDIP) in OMS

SMIA supports the following actions on the jobs: › Create › Stop › Modify › Copy › Delete › Save job details as profile › Inform the jobs to SGw

Measurement Initiation and Administration (MIA) is used to initiate

counters on the following Network Elements: › M-MGw,XC,Sgw (Cello) Network Elements › SGSN Network Elements › GGSN Network Elements › CGSN Network Element


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Storage of MEASUREMENTS

Statistical Gateway (SGw), and the Performance Management Subsystem (PMS)


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Statistical Database Administration


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NWS Analyzer

Network Statistics Analyzer provides 196 predefined reports


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GSM RAN REPORTS› Overview Reports

Performance Overview, BSC and Cell Set Radio Overview, BSC and Cell Set

› Planning Reports AMR Codec Mode Utilization Cell, BSC Call Setup Performance Overview, BSC and Cell Set CP Load, BSC Hardware Dimensioning, BSC and Cell Set OL/UL Subcells, BSC and Cell Set Random Access, BSC System Performance Charts Traffic Trend Normal, BSC and Cell Set Traffic Trend PEAK, BSC Paging Statistics, BSC

› Dropped Calls Reports Dropped Calls Overview Dropped Calls Cell, BSC and Cell Set Dropped Calls Trend BSC, Cell Set and Cell

› Handover Reports Handover Activity, BSC and Cell Set Handover Performance Overview, Cell Set Handover Performance Per Cell, BSC and Cell Set Handover Performance Per Cell Relation, BSC and Cell Set Handover Performance OL/UL, BSC and Cell Set Inter BSC Handover Performance Intra-Cell Handover Overview, BSC and Cell Set

› Management Reports Abis Link Utilization Infrastructure Radio Network Performance Switch Performance, BSC Peak Hour Performance, BSC

› Speech Quality Supervision Speech Quality Cell, BSC Speech Quality Chart, BSC and Cell

› Dual Band Reports Dual Band Mobile Performance Cell, BSC and Cell Set Dual Band Mobile Performance Trend Cell, BSC and Cell Set

› GPRS BSC Reports (from revision 07B and onwards) GPRS GSL Device Utilization BSC GPRS CCCH Load and Paging Load Cell, BSC GPRS IP Discards and TBF Issues Cell, BSC GPRS RPP Load BSC GPRS Performance Overview in Overlaid Subcell GPRS Performance Overview Cell, BSC GPRS Radio Link Quality in Overlaid Subcell GPRS Traffic Load Cell BSC GPRS IP Throughput Cell, BSC GPRS Radio Link Quality Cell, BSC GPRS DTM Performance per Cell, BSC GPRS IP Latency Cell, BSC

› Scheduled reports Hardware dimensioning, BSC and Cell Set OL/UL Subcells, BSC and Cell Set

› Management Reports Abis Link Utilisation Infrastructure Radio Network Performance Switch Performance, BSC Peak Hour Performance, BSC

› Speech Quality Supervision Speech Quality Cell, BSC Speech Quality Chart, BSC and Cell

› Dual Band Reports Dual Band Mobile Performance Cell, BSC and Cell Set Dual Band Mobile Performance Trend Cell, BSC and Cell Set

› GPRS BSC Reports (from revision 07B and onwards) GPRS GSL Device Utilization BSC GPRS CCCH Load and Paging Load Cell, BSC GPRS IP Discards and TBF Issues Cell, BSC GPRS RPP Load BSC GPRS Performance Overview in Overlaid Subcell GPRS Performance Overview Cell, BSC GPRS Radio Link Quality in Overlaid Subcell GPRS Traffic Load Cell BSC GPRS IP Throughput Cell, BSC GPRS Radio Link Quality Cell, BSC GPRS DTM Performance per Cell, BSC GPRS IP Latency Cell, BSC

› Scheduled reports Hardware dimensioning, BSC and Cell Set OL/UL Subcells, BSC and Cell Set


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Example Report


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Counter Aggregation

Exactly how and when the aggregation is performed can be set up in SDM.


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Peak Types

› Daily Peak Hour (DLYPH) The peak value for the whole day, from midnight to midnight

› Morning Peak Hour (DAMPH)› Afternoon Peak Hour (DPMPH) It is the

Daily peak hour that is calculated for the first part of the day, as per the AM/PM break value mentioned in the SDM GUI. It is the Daily peak hour that is calculated for the second part of the day, as per the AM/PM break value mentioned in the SDM GUI Time

› Consistent Peak Hour (TCPH) The peak value during a specific period of the day. This time period is set in SDM for each managed object, and can be different for different objects.


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Business Objects Administration

NWS products NWS-A and PMR-A is being replaced with ENIQ.


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ESPA – web based Ericsson Tool


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RN Counters and KPIs


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Counters and Formulas in BO

› Overview reports › Planning reports › Dropped Calls reports › Handover reports › Management reports › Speech Quality Supervision reports › Dual Band reports › GPRS BSC reports


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Performance overview BSC and Cellset

BO Predefined Report


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BSS RADIO NETWORK KEY PERFORMANCE INDICATOR (KPI) GUIDELINE› The KPIs reflect the end-user perception of the performance of BSS as far as possible rather

than the system view.› The KPIs are though only based on what can be measured in BSS.› For GPRS end-to-end KPIs on service level need other types of measurements.› The KPIs are possible to collect from STS statistics and are formulated on counter level. › If a particular formula differs between releases, alternative formulas are given for different

releases.› The KPIs are formulated on cell level; they can though of course be aggregated on BSC or

system level. › It has been commented per KPI if a simpler version of the formula can be used if applied on

BSC or system level.› PERLEN stands for measurement period length in STS (minutes), and is available as a

parameter in STS. › NB_CELLS means number of cells for one BSC

The Radio Network KPIs for BSS used within Ericsson are being aligned within Ericsson, for example NetQB


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Comments on Formulas› Formulas that include handovers have considered handovers both to BSC internal and external

neighbors. If data is only collected from one BSC it is not possible to obtain the incoming handovers from external cells, so then all handovers for external cells could be omitted.

› For formulas handling handovers user defined summation counter have been used. The summation counters are not part of the BSC STS counters, but should created on cell level in a post-processing tool.

› The STS object types that contain counters for BSC internal cell relations are NCELLREL and NICELASS, and for BSC external cell relations NECELLREL and NECELASS.

› Note that for External Cells (i.e. cells belonging to different BSCs, e.g. "BSC1" and "BSC2") the Object Type NECELLREL only shows outgoing HO (STS data from a BSC only report counters for that particular BSC). Hence, in order to have a proper Summation, one must combine the NECELLREL Object Types from "BSC1" and "BSC2", respectively, in a post-processing tool. When looking at Internal Cells (cells belonging to the same BSC), i.e. Object Type NCELLREL, both incoming and outgoing HO is shown.

›

Circuited Switched KPI


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Overview of Circuit Switched KPIs

Accessibility

For setting up a signaling connection the mobile might try several times for each call setup. Thereby building up a combined total metric for accessibility success rate is not recommended, as one access failure seen from the subscribers will be seen as several access failures in the system. Each step in the call set-up process should thus be accounted for separately and for SDCCH availability time congestion is a better measure than success rate.


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Random Access Success Rate

Percentage successful random accesses.

Formulas in BO

A failed random access burst does not mean a failure to access the system, as the mobile may send many random access bursts each time it tries to access the network. E.g. bad BSIC planning, too high TA, parameter settings (e.g. MAXRET) or interference might cause a high number of random access failures.

The KPI covers random accesses over RACH both for CS and PS connections, but not over PRACH (when using a MPDCH). Only failures related to the random access as such are considered, rejects due to load regulation are not included and can be monitored by separate counters.


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SDCCH Time Congestion

SDCCH time congestion, percentage of the time.

Formulas in BO

Congestion on SDCCH might not lead to a call set-up failure as the mobile may retry several times to set-up an SDCCH in case of congestion (controlled by the MAXRET parameter). Also if immediate assignment on TCH is allowed the call set-up may proceed on a TCH even if there is SDCCH congestion. SDCCH time congestion starts incrementing when all channels are occupied, even if there are no rejected accesses.

If there is an SDCCH in both the OL and the UL subcell the KPI will over estimate the congestion as there might be available channels in one subcell even if the other is congested. Note though that some mobiles may not be capable or able to access both subcells.

The systems are normally dimensioned to have a certain SDCCH GoS, so the KPI should be compared to the GoS that the system was planned for. The system should normally be dimensioned with low SDCCH congestion, as a rule of thumb the SDCCH Grade of Service (GOS) should be dimensioned for no more than ¼ of the TCH GOS. Even if the SDCCH congestion is normally very low it is important to monitor it as it can rise sharply due to subscriber behaviour, e.g. through heavy usage of SMS or positioning using AGPS.

If the feature Adaptive configuration of logical channels is used SDCCH congestion is prevented by allowing on-demand SDCCHs to be allocated in case of congestion, and monitoring the SDCCH congestion is less critical.


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SDCCH Drop Rate Percentage drops on SDCCH channels.

A drop on SDCCH does not mean a failed call set-up since it can be used for procedures that only require an SDCCH like a location area update or SMS. In fact as the SDCCH holding time for call set-up is just under 3 seconds and about twice as long for SMS, drops for SMS should be over represented.

The KPI does not include released SDCCH connection due to TCH or transcoder congestion (i.e. the CNRELCONG counter), as it is seen in the TCH assignment success rate KPI. The drop rate is related to all SDCCH establishments in the cell; no compensation has been done for SDCCH handovers, but as the mobiles normally camp on the SDCCH a short time SDCCH handover occur seldom.

A high SDCCH drop rate may be due to:

• Poor coverage

• Interference

• Equipment faults (e.g. BTS or mobile related)

• Subscriber behavior (sending frequent large SMS, using AGPS positioning or causing sudden loss e.g. entering an elevator)

• Power congestion (overload) if using MCPA based TRXs. (See MCPA Guidelines in Alex)


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TCH Assignment Success Rate

Percentage successful first TCH assignments for the mobiles that tuned in to signaling in the cell.

If the formula is used on BSC or system level handovers do not need to be considered.


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TCH Assignment Success Rate› The assignment success rate covers both change from SDCCH to TCH or changed channel mode on TCH from signaling to speech.› It should be noted that during the assignment procedure there may be several attempts to allocate a channel in different cells, but the

attempts counter in this formula (TASSALL) will only be incremented once, if an attempt succeeds or if all attempts have failed.› A low TCH assignment success rate would normally be due to TCH congestion. › The KPI shows the subscriber perceived TCH availability at call setup and is impacted by parameter settings e.g. for the assignment

time-out (TASSREQ) and assignment to worse or better cell (e.g. AWOFFSET). › The systems are dimensioned to have a certain TCH GoS, so the KPI must be compared to the TCH GoS the system was planned for. › Note that congestion at hand-over is not included in this KPI, or any other KPI, as there is no way to determine the subscriber impact

due to a hand-over that could not be executed due to congestion. › As a second level measurement the channel availability in the cells should be monitored in terms if congestion time, this is though not a

KPI as it does not directly translate into a subscriber impact (with features like OL/UL subcells, Hierarchical Cell Structures, assignment to worse cell and dynamic mode adaptation subscriber impact due to lack of channels is prevented).

› The KPI does not only show failures due TCH congestion, but also includes other reasons for failures to establish a TCH like transcoder congestion, CLEAR COMMAND, RESET or RESET CURCUIT received from the MSC, Ater RESET or Ater RESET CURCUIT received from the TRC, MS lost, link connection or HW failure during the assignment process.

› The TCASSALL and TASSALL counters in the formula for successful assignments are stepped in the target cell; if the assignment fails the TASSALL counter is stepped in the serving cell (the cell where the MS was tuned in for signaling).

› To show how many mobiles that tuned in for signaling in the cell that managed to establish a TCH outgoing assignment handovers are added (they managed to get a TCH in an other cell) and incoming assignment handovers are subtracted (they tuned in to signaling in an other cell) from both the numerator and the denominator.

Retainability


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TCH DROP RATE

Percentage dropped TCH connections of the total number of TCH connections terminated in the cell.

If the formula is used on BSC or system level handovers do not need to be considered.

I recommend another formula as it is independent of were the call startedas well as of any handover.


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TCH Drop Rate› To capture the subscriber perceived drops in a cell the number of calls terminated in the cell are considered, i.e.

compensation is done for incoming and outgoing handovers for all internal and external cell relations.› It is important to note that the TCH drop counters are stepped as soon as a TCH is established even if there has yet not

been any B-answer, this is also applies when TCH is used for signaling. › If the TCH is dropped before the B-answer the subscriber will experience it as a failed call set-up rather than a dropped

call. If TCHs are used extensively for signaling one reason for increased TCH drops could be transcoder congestion, it can be seen in the counters THNRELCONG, THNRELCONGSUB, TFNRELCONG and TFNRELCONGSUB.

› TCH connections that are lost during handovers are also seen as TCH drops in the counters.› If Adaptive Multi Rate (AMR) is used the subscriber will experience better speech quality and is more likely to hold on to

the call until it drops rather than disconnecting the call due to poor speech quality, thus the drop rate might increase slightly when AMR is introduced.

› There are separate dropped call counters for AMR, which allows drops for AMR connections to be monitored separately.› As HOVERSUC includes successful SDCCH handovers, the drop rate on cell level can be skewed if there are a large

number of SDCCH handovers. › The mobile though camps on the on the SDCCH only a short period of time and number of SDCCH handovers is

normally small compared to the total number of TCH assignment, typically less than one percent.› Due to reduced interference when using different RN features in the Radio Network, the KPIs such as TCH drop rate

and for SQI distributions are is expected to improve. To what extent is highly depending on radio network design and existing frequency plan.


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TCH DROP RATE

› A high TCH drop rate may be due to:› Poor coverage › Interference › Hardware faults (e.g. transcoder, BTS or

mobile related) › Subscriber behaviour (e.g. causing sudden

loss by entering an elevator or pulling out the battery)

› Handover failure › Too high timing advance (TA) › Power congestion (overload) if using MCPA

based TRXs

T_DR = TNDROP / (TNDROP+DISNORM)

My recommendation

It is NOT important were thecall started BUT were it ENDED.

Thus we can ignore TCASSALLand all Handovers in the dropformula…….

Also time is eliminated as a factor.A call that starts in hour n can drop in hour n+1.


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Call Minutes Between Drops Average time period between TCH drops in minutes.

This KPI complements the TCH drop rate KPI as the call holding time may differ in different networks or in different parts of one network, which may impact the TCH drop rate.

Formula in BO


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Handover Success Rate

Percentage successful handovers. Summed up for all external and internal cell relations.

Formula in BO

The KPI does not only cover TCH handover but also handovers during assignment and SDCCH handovers.

A low handover success rate may be due to not optimized cell plan, parameters or neighbor relations.

The handovers that are not successful or not lost revert to the old cell. A high rate of reverted Handovers could indicate that there exists two cells with the same BSIC -BCCH combination, and both of them are defined as neighbors. Other reasons are that the handover is attempted before the uplink in the new cell works, and the old cell is sufficiently good for allowing a reversion. The failure in the new cell can be too aggressive settings for HO, or an indication of a faulty RX in the target cell with lower sensitivity.

Note that Handover reversions do occur in any network even at good conditions - normally the rate is around 1%. The reason for this is likely temporary dips, collisions in the air interface etc. The Handover failure is not perceived by the subscriber, but could lead to a subsequent drop due to penalties in locating and handovers to other cells that are not good candidates.


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Handover Lost Rate Percentage MS lost at handovers. Summed up for all external and internal cell relations.

The KPI does not only cover TCH handover but also handovers during assignment and SDCCH handovers.

The KPI shows the subscriber perceived impact due to failed handovers, as it shows the percentage of handover that resulted in a lost call. This KPI is important to correlate to the TCH drop rate since a lost handover for a TCH will also bee seen in the TCH drop KPI.

Look at #calls, #handovers, #drops, #HO lost and #HO per call

Integrity

The Integrity KPIs are based on the Speech Quality Supervision function, which is a method to measure and monitor the speech quality in the network based on radio quality information. The speech quality is determined by monitoring the radio conditions for each ongoing call in the network. The radio conditions are converted to a Speech Quality Index (SQI) which corresponds to a subjective speech quality.


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Integrity› SQI is in R10 and R11 is available on the uplink.› In R12 with the features EMR and SQS enhancements SQI on the downlink will be available for EMR

capable mobiles. › Formulas applicable from BSS R10 to BSS 07B should be used with care in newer releases. › In 08A support for AMR wideband is introduced. Hence, additional formulas including AMR wideband

(Speech version 5) applicable from 08A and onwards are introduced.› In R11 STS counters for RXQUAL uplink and downlink are introduced. › The RXQUAL distribution for different hopping networks (or different network configurations) will not truly

reflect the difference in subjective speech quality of the networks. The RXQUAL measure can thus not be used for benchmarking, and should therefore not be used as a KPI.

› However, RXQUAL is still interesting when comparing between cells within one network.› Note that packet ABIS influence on speech quality will not be visible in the SQI values UL and DL,

respectively.› Due to reduced interference when using the optional feature Dynamic BTS Power Control and Dynamic

MS Power Control, KPIs such as TCH drop rate and SQI distributions are expected to improve. To what extent is highly depending on radio network design and existing frequency plan.


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SQI UL Good R10 — 07B

Percentage SQI samples with good quality of total number of SQI samples in both OL and UL subcells.

SQI for AMR calls and non-AMR calls are counted separately……


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SQI UL Acceptable R10 — 07B

Percentage SQI samples with acceptable quality of total number of SQI samples in both OL and UL subcells.


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SQI UL Bad R10 — 07B

Percentage SQI samples with unsatisfactory quality of total number of SQI samples in both OL and UL subcells.


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SQI UL Good 08A and onwards, AMR wideband included.

Percentage SQI samples with good quality of total number of SQI samples in both OL and UL subcells.


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SQI UL Acceptable 08A and onwards, AMR wideband included.

Percentage SQI samples with acceptable quality of total number of SQI samples in both OL and UL subcells.


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SQI UL Bad 08A and onwards, AMR wideband included.

Percentage SQI samples with unsatisfactory quality of total number of SQI samples in both OL and UL subcells.


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SQI DL from R12 and onwards

› The formulas are the same as for UL only replace UL with DL.› Only EMR capable phones will report DL measurements› In a network not all mobiles will be EMR capable› Implementing EMR can degrade performance if the mobile is not able to

correctly handle EMR reporting.› If the mobile is not EMR capable it should send measurement report the as if

EMR was not implemented.

Inter System Operability

A UTRAN cell is considered as a candidate for handover in the GSM system if the signal quality in the target cell is good enough. When prioritizing between UTRAN or GSM the traffic load of the GSM cell is also used as a criterion for handover towards UTRAN. Only outgoing handovers from GSM cells to UTRAN cells are counted in BSS. Similar counter exist in the UTRAN system that cover handovers from UMTS to GSM.GPRS Cell Reselections to UMTS are not counted in BSS since the BSC is not aware if a mobile moves to another GSM BSC or to the UTRAN network.


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GSM to UTRAN Handover Success Rate

Percentage successful GSM to UTRAN handovers.

The KPI covers SDCCH and TCH handovers to UTRAN, no handovers during assignment are done to UTRAN.

The handovers to UTRAN are not seen in the general retainability KPIs for handover success rate and handover lost rate.

Generally the handovers to UTRAN are only seen in the UTRAN specific handover counter in BSS, except for the SDCCH hand over counters on cell level where they are included.


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GSM to UTRAN Handover Lost Rate

Percentage MS lost at GSM to UTRAN handovers.

The KPI shows the subscriber perceived impact due to failed GSM to UTRAN handovers, as it shows the percentage of handover that resulted in a lost call.

This KPI is important to correlate to the TCH drop rate since a lost handover for a TCH will also bee seen in the TCH drop KPI.

The handovers that are not successful or not lost will revert to the old cell.

Traffic

Traffic level is not a KPIs in its own right, but can be used to relate to changes in other KPIs, e.g. a sharp increase of traffic might explain an increased congestion or degraded speech quality (many half rate connections).


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Traffic

Average TCH traffic in Erlang.

Average SDCCH traffic in Erlang.

GPRS KPI in BSS

In the telecom world network performance is often defined in the ITU terms accessibility, retainability and integrity. These terms work well in a circuit switched network; accessibility relates to blocked calls, retainability to dropped calls and integrity to speech quality. For the end user in a packet switched system it is though difficult to define measures in the BSS, that relate these terms to the end user perception of service quality.


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GPRS KPI in BSS

› The GPRS/EGPRS/EGPRS2-A system has many layers of protocols. A user session where a TBF lost, which would be a retainability problem in BSS, will normally be kept alive by higher protocol layers (e.g. TCP) until a new TBF is established. To the user this seems like an integrity problem, a session that included a short delay. The higher layer protocols are transparent to BSS.

› The GPRS/EGPRS/EGPRS2-A network is a bearer for a number of different services. These are affected by events in the network in different ways. For example if BSS failed to transfer any data for 5 seconds it would be a serious problem for a WAP user, but hardly be noticed by a user down loading emails in the background.

› The end-user services are also normally not visible to BSS.› The terms accessibility, retainability and integrity can be applied to the

GPRS/EGPRS/EGPRS2-A system, but only on higher layers and by considering events that are invisible to the BSS.


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GPRS KPI in BSS

› Most BSS GPRS KPIs in are integrity KPIs on end-user level (with exception of GPRS availability.

› Accessibility and Retainability on GPRS Attach and PDP context level should be measured in the GPRS nodes (SGSN and GGSN).

› The GPRS KPIs in this document are directly related to the BSS ability to transfer IP packets, which impact the user perception of the service.

› To trouble shoot deviations found in the KPIs lower level performance indicators must be used.

› Apart from using STS counter further detailed troubleshooting can be done with other applications like R-PMO.


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GPRS KPI in BSS

› As different characteristics are important depending on what type of application that the end-user is running the BSS GPRS KPIs have been put in the following categories or application types:

1. General GPRS KPIs that are relevant for all types of transfers. 2. Best effort services (traffic class interactive and background). This could

typically be email downloads, WAP session and ftp. 3. Streaming (traffic class streaming). This could typically be real time viewing of

film clips. 4. Dual Transfer Mode, a simultaneous CS call and PS data transfer. DTM is not

an application as such, but needs to be monitored separately since fewer timeslots can be used for the PS connection and as the mobility pattern will differ compared to pure PS connections.


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Overview of BSS GPRS KPI

++ : Significant impact on end-user performance

+ : Impact on end-user performance

I : Included in KPI, no direct impact on end-user performance

0 : Not included in KPI or not applicable


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Optimization Example› For interactive and background transfers this means minimizing the total transfer time (i.e. for each WAP page, web page, email transfer,

MMS transfer etc). The best way to do this is to calculate the total transfer time as a function of the IP throughput, IP latency and IP transfer interrupts.

› An operator wishes to optimize the GPRS network for the download of an “average” web page. › This consists of 5 objects of size 9 Kbyte (giving a total of 45 Kbytes of data). To transfer these 5 TCP objects 20 Round Trip Times are

needed (for TCP handshake messages and TCP slow starts). › A bit simplified the transfer can be modeled as:› The measured average IP throughput is 30 kbit/s. Transfer time = (45*8)/30 = 12 seconds.› The measured average IP latency is 600 ms. Total latency time = 20 * 600 ms = 12 seconds.› The measured average TBF time per IP transfer interrupt = 20 minutes or 1200 seconds. › Assume each interruption lasts for 5 seconds. › If one web page takes a total of 18 seconds to download then a user should, on average, be able to download a total of 66 web pages

without any problems. An interruption of 5 seconds will be experienced in the next download. (18*66=1188 seconds)› Another way to look at this is to say that for every 1 second of TBF time there is, on average, an added 0.0042 seconds (5/1200) of

interrupt time. So added interrupt time = 18 * 0.0042 = 0.076 seconds.› So for this application the IP throughput and the IP latency are equally important. The impact of the IP transfer interrupts is more

subjective - is one interrupt in every 67:th web page too much?› Different operators will have different focus on different applications. For example for WAP the IP latency will be a much larger part of the

total transfer time.› It's important to note though that improving the IP throughput or IP latency will improve the performance for all applications (just two

different degrees depending on whether the application is throughput or latency sensitive).

General GRPS KPI


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Session Minutes per IP Transfer Interrupt Downlink

Average downlink data session transfer in minutes per downlink IP buffer discard. DTM transfers not included.

R11:

G11B:

The KPI Session minutes per IP transfer interrupt downlink is a combined user integrity measure for mobility, TBF retainability and TBF accessibility assuming the delay or interruption to the user transfer is similar in all cases, typically in the order of 3-7 seconds.


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Session Minutes per IP Transfer Interrupt Downlink› The IP throughput counters measure the speed with which the BSS ships IP packets to and from the users. But what

happens when the BSS has received IP packets from the SGSN but cannot transfer these to the MS for some reason (perhaps the BSS could not set-up a connection to the MS or the connection was broken mid-transfer)? Then the entire contents of the buffer in the PCU and SGSN will be discarded.

› Even if, as is likely in most cases, the data transfer is automatically re-established fairly quickly by the higher layer protocols (TCP or UDP), there will still be some impact on the transfer of IP packets from the discard. The transfer interrupts downlink KPI is measured as the number of complete downlink buffer discards per downlink TBF minute.

› For TCP transfers this will usually result in a temporary reduction in the send rate of the TCP connection (TCP congestion avoidance and/or slow start).

› For UDP transfers the application may request re-sending of the discarded data.› The user experience of an IP buffer discard is heavily dependent on the application he/she is running. But there will be

some interruption in the transfer since the buffer is empty after the discard. It is the number of these interruptions in service that are important to measure rather than the amount data discarded.

› Shorter delays induced by an inter Routing Area or inter PCU cell reselection do not cause any PCU buffer discard are not considered in the KPI, these interrupts are normally in the range of 2-3 seconds and can be monitored by the FLUMOVE counter. With the feature network assisted cell change this time will be reduced even further, down to one second.

› In R11 with the feature loss less pre-emption the downlink IP buffer is kept during 5 seconds after a TBF is lost, the interrupt that will occur if a new TBF is established during this time is not visible in this KPI, but will be seen as a reduced throughput for the transfer.


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Session Minutes per IP Transfer Interrupts Uplink Average uplink data session transfer in minutes per abnormally released TBF Uplink and access reject.

DTM transfers not included.

R10:

R11:

06B:

08A:

G11B:


(32 pt makes 2 rows








Session Minutes per IP Transfer Interrupts Uplink

› Prior to the 06B release, the counter IAULREL stepped also due to Cell Reselections. In the 06B release and onwards, the Cell Reselection contribution to IAULREL has been removed and is handled by the counter CRSULREL.

› Prior to the 08A release, the counter PREJTFI stepped also due to Abis congestion. In the 08A release and onwards, the Abis contribution to PREJTFI has been removed and is handled by the counter PREJABISCONG.

› G11B: Formula updated in order to include EGPRS2-A.› The KPI Session minutes per IP transfer interrupt uplink is a combined user

integrity measure for mobility, TBF retainability and TBF accessibility assuming the delay or interruption to the user transfer is similar in all cases, typically in the order of 3-7 seconds.


(32 pt makes 2 rows








Session Minutes per IP Transfer Interrupts Uplink› Ideally there should be a mirror image of the IP buffer discard counters for the uplink. However it is

impossible for the PCU to know when the MS has decided to discard the contents of its IP buffer.› Instead we measure the number of times the PCU knew the MS had data to send but was unable to for

some reason. These can be split into two areas:– MS Access Rejects (MS request to set-up an uplink TBF must be repeated) – MS to BSS connection loss (Ongoing uplink TBF released)

› A rejected packet access means that the MS has to retry its attempt to access the system. Normally the MS is prevented from attempting packet accesses in the same cell until the Wait Indication has expired (T3412 specified in the Immediate Assignment Reject message or T3172 (optional) specified in the Packet Access Reject message). This value is always 5 seconds in the Ericsson BSS.

› A rejected packet access does not directly relate to a failure to transfer IP packets on the uplink since a packet access procedure is still required for other purposes (for example for the transfer of GMM/SM signaling). However the ratio of rejected packet access will give a good indication if there are problems in the cell.

› When the MS to BSS connection is lost due to radio reasons, again, this does not indicate a direct impact on the users in terms of a failure to transfer IP packets on the uplink, but does gives an indication that there may be coverage and/or interference problems in the cell.


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GPRS Availability

GPRS Availability Cell Level (R10 and R11)Measure of GPRS availability per Cell.

If the result is 0 the cell is likely not available for GPRS if 100% it is considered available.

GPRS_AVA_C should be calculated per cell and measurement period and be aggregated as a status counter i.e. be averaged over time.


(32 pt makes 2 rows








GPRS Availability

GPRS Availability (R12 and Onwards)

GPRS Availability BSC Level

Measure of GPRS availability per BSC, the average percentage of cells considered as not being available for GPRS. If formula is applied on aggregated data it shows the percentage of cell time available for GPRS, with the measurement period in STS as granularity.


(32 pt makes 2 rows








GPRS Availability› The GPRS Availability KPI is based on measurements showing cells that are suspected to be unavailable

for GPRS.› In the cells with no GPRS traffic uplink or downlink during the last 5 minutes attempts are made to inject

Packet Switched traffic by forcing a limited number of suspended GPRS attached MSs present in the cell to perform a Routing Area Update.

› The GPRSAVA counter counts each injection. If the number of traffic injection attempts over the chosen measurement period is five or more, but the data transferred is still zero uplink or downlink the cell is suspected to be unavailable for GPRS.

› As mobiles might be close to cell borders and perform a Routing Area update to an other cell at least a certain number of injections are required to consider the cell as suspected to be unavailable.

› That GPRS is unavailable in a cell may not be due to problems in BSS, but in other parts of the GPRS network.

› It should be noted that the formula on cell level only works on data that has not been aggregated over time. The result of the formula should be aggregated as a status counter, i.e. by averaging over time.

› As from R12 and onwards, a new peg counter GPRCELLAVA can be used for a simpler formula that do not require intermediate results to be calculated on cell level to aggregate on BSC level. Using this formula GPRS availability can be measured down to 5 minutes level.

GPRS Best Effort Service KPIs

(Traffic Class Background and Interactive)


(32 pt makes 2 rows








IP Latency

The picture below shows the time that will be measured as the BSS-MS-BSS IP latency.


(32 pt makes 2 rows








IP Latency

› The IP latency BSS-MS-BSS is measured on small IP packets received on the Gb interface where a small IP packet is received on the uplink in response.

› The size limit for the IP packets is currently an LLC data volume of 70 bytes both for the uplink and the downlink.

› The time is measured from the downlink packet is received on the GB interface until the uplink packet is sent onto the GB interface, i.e. it measures the delay Gb-BSS-MS-BSS-Gb, which in the majority of the GPRS networks contributes to more than 90% of the total client-server round-trip time.

› Note that also delays induced by the mobiles, laptop and mobile-laptop communication are included in the KPI.


(32 pt makes 2 rows








IP LatencyIP Latency BSS-MS-BSS GPRS

Average IP latency BSS-MS-BSS for GPRS capable mobiles, regardless of extended UL capability. R11 and onwards.

IP Latency BSS-MS-BSS EGPRS/EGPRS2-A

Average IP latency BSS-MS-BSS for EGPRS/EGPRS2-A capable mobiles without Reduced Latency capability (3GPP R7) –

regardless of extended UL capability. R11 and onwards.


(32 pt makes 2 rows








IP Latency

Average IP latency BSS-MS-BSS for EGPRS/EGPRS2-A and Reduced Latency (3GPP R7) capable mobiles –

regardless of extended UL capability. 08B and onwards.


(32 pt makes 2 rows








IP Latency

› The IP latency is affected by parameter settings for PULS (Persistent Uplink Scheduling) and Reduced Latency, penetration of 3GPP R4 capable mobiles that are capable of “Extended UL TBF” and Reduced Latency, the traffic load, radio link quality and the coding schemes used.

› The formulas have been separated for EGPRS/EGPRS2-A and GPRS as the higher throughput for EGPRS/EGPRS2-A transfers will give better latency and to enable better correlation with the IP throughput KPIs that are separated for GPRS and EGPRS/EGPRS2-A transfers.

› Note though that for the throughput KPIs the combination EGPRS/EGPRS2-A/GPRS relates to the TBF mode while for latency it relates to the MS capability.

› The latency in BSS will differ depending on when in a session the IP latency is measured. There are two different IP latencies that can be measured:– Out of session latency- latency for transfers that are not within a session (i.e. no DL TBF is set-up) – In session latency - latency for transfers that are within a session (i.e. DL TBFs are already set-up)


(32 pt makes 2 rows








IP Latency

In Session Latency› The KPI for BSS IP latency measures the “in session latency”.› For end-users running TCP/IP applications (which are predominant in the networks today) it is

the in session latency that is important while the out of session latency impacts the end-user performance only marginally.

Out of Session Latency› The out of session latency (measured e.g. by the first ping in a ping series) corresponds to the

first access after a period of end-use idleness. The out of session latency is important only for a very limited set of applications. The out of session latency (first Ping) will be consistently longer than the in session latency (consecutive Pings). This is because the time for the first ping includes set-up times for one UL and one DL TBF (which takes 300 - 500 ms in total). In contrast the following Pings in the series use already established DL TBFs and (in case of 3GPP R4 terminals) already established UL TBFs. The first ping takes ~ 200 ms longer time for EDGE than for GPRS (due to the EDGE two-phase access) while the latency for the following pings is equal for GPRS and EDGE.

› The out of session latency is not measured by counters BSS.


(32 pt makes 2 rows








IP Throughput GPRS

IP Throughput UL GPRSWeighted throughput, interactive and background transfers, GPRS transfers uplink.

IP Throughput DL GPRSWeighted throughput, interactive and background transfers, GPRS transfers downlink.


(32 pt makes 2 rows








IP Throughput EGPRS

IP Throughput UL EGPRSWeighted throughput, interactive and background transfers, EGPRS transfers uplink.

IP Throughput DL EGPRSWeighted throughput, interactive and background transfers, EGPRS transfers downlink.


(32 pt makes 2 rows








IP Throughput EGPRS2-A

IP Throughput UL EGPRS2-AWeighted throughput, interactive and background transfers, EGPRS2-A transfers uplink.

IP Throughput DL EGPRS2-aWeighted throughput, interactive and background transfers, EGPRS2-A transfers downlink.


(32 pt makes 2 rows








IP Throughput LLC› The IP throughput measurement has been designed to reflect the subscriber perceived throughput and is measured per

PFC for the “active PFC lifetime” i.e. when there is data to send in the downlink buffers or when data is being sent uplink.

› The “active PFC lifetime” timer also includes the set-up time for downlink TBFs. › The timer is stopped a soon as there is no user data in the PCU buffer and the measured throughput is not impacted if

the TBF is kept alive artificially by the system, for example by the feature “Delayed release of DL TBF”. › The IP throughput is weighted by data volume, i.e. a transfer of 100 KB will contribute 10 times more to the weighted IP

throughput than a transfer of 10 KB. › There is no lower limit to how small transfers that are included.› As the measured throughput is based also on the TBF setup time (which is approximately 180 ms) small transfers will

consistently show lower throughput than large transfers even if the throughput when the TBF has been set-up is the same.

› This means that in cells with a very large amount of small transfers and few large transfers the measured throughput will show low values even if the subscriber perceived throughput for larger transfers (where throughput is has most impact on the user perception) is good.

› Technically speaking the counters show throughput on the LLC layer rather than the IP layer, but the LLC overhead is very small. E.g. a 500 byte LLC PDU only contain 11 byte, or 2.2%, of header data.

› The IP throughput is impacted by e.g. the radio link quality, Abis link quality and capacity, the number of PDCHs reserved per transfer, the capabilities of the mobiles, the traffic load in the system and the traffic pattern (smaller transfers will have lower measured throughput).

› Note that the IP Throughput may be negatively affected if there is a power congestion (overload) when using MCPA based TRXs


(32 pt makes 2 rows








Streaming KPIQoS Negotiation Success Rate

Percentage of QoS negotiations resulting in the requested GBR, XX relates to the GBR intervals the counters are divided in.

The characteristics of streaming transfers differ in many important aspects from the best effort services. Streaming transfers require a fixed throughput that is held consistent throughout the whole session; throughput for streaming transfers is thus not good measure of BSS performance. The reservations for streaming transfers differs compared to other traffic classes and at high traffic load new streaming sessions will not be admitted or not get the requested Guaranteed Bit rate (GBR).


(32 pt makes 2 rows








Streaming

› The parameters BPDCHBR, GPDCHBR and EPDCHBR are used to reserve a number of effective streaming PDCHs that are required to meet the requested GBR that is stored in the ABQP. The streaming transfer will have absolute priority on the effective streaming PDCHs and they are normally not allowed to be pre-empted. If the parameter settings are well tuned the normal problem for streaming sessions at resource shortage will be getting the requested GBR for a transfer.

› The GBR is negotiated with the SGSN and by monitoring the outcome of these attempts to reserve resources it can be seen if the users get the GBR, and hence the quality of service, they requested. The success rate will vary with the type of streaming traffic in the cell (higher requested GBRs are more difficult to serve). As a second level measurement it should be verified that the parameters are set so that the reservation really meets the granted GBR.

› IP transfer interrupts are important for streaming transfers as it will be experienced by the end-user as a bigger disturbance for streaming than for best effort services.


(32 pt makes 2 rows








Dual Transfer Mode KPI (R11 and forward)

DTM IP Throughput ULWeighted throughput, interactive and background traffic classes, EGPRS and GPRS uplink, R11 only.

DTM IP Throughput DLWeighted throughput, interactive and background traffic classes, EGPRS and GPRS downlink, R11 only.


(32 pt makes 2 rows








Dual Transfer Mode KPI (R11 and forward)

› Dual Transfer Mode (DTM) enables a user to run a CS call and PS data transfer simultaneously.

› The throughput for DTM connections will be consistently lower than for other transfers as fewer timeslots can be used for the PS connection.

› There are a number of additional counter for DTM connections that allow for example multi slot utilisation, downlink buffer discards, accesses and lost uplink TBFs to be monitored separately for DTM connections.

› The KPI will provide an accessibility metric for DTM connections, which is considered to be an important aspect as there are tougher restrictions when allocating a DTM connection than a pure CS or PS transfer (e.g. the available timeslots must be arranged a certain way).


(32 pt makes 2 rows








Dual Transfer Mode Allocation Success Rate KPI (R12 and onwards)

DTM Allocation Success Rate, R12 - 07B

DTM Allocation Success Rate, 08B and onwards, AMR wideband included


(32 pt makes 2 rows








Dual Transfer Mode Allocation Success Rate KPI (R12 and onwards)

› With the new R12 counter TDTMALLOCAT it is possible to calculate the DTM allocation success rate for all MSs that were allowed to enter DTM mode (prerequisite for allocating resources).

› In conjunction with the introduction of AMR wideband in 08A, TDTMALLOCAT is updated and includes also AMR wideband allocation attempts.

› The KPI shows the percentage of the requested DTM connections (UL and DL) that were allocated at least one PDCH and one FR or HR CS channel, in relation to the ones that were accepted by the system.

› A possible reason not to accept a DTM connection setup attempt is that the CS call is in an unstable state (during handover, performing ciphering initiation etc).

› If the DTM allocation success rate is not satisfactory the reason could be that there are too few idle TCHs or too few transcoder-, GSL- or Abis resources.


(32 pt makes 2 rows








IP User Data Volume

IP User Data Volume DownlinkLLC data volume for the whole cell including all traffic classes except GMM/SM signaling.

R10:

R11 and onwards:


(32 pt makes 2 rows








IP User Data VolumeIP User Data Volume Uplink

LLC data volume for the whole cell including all traffic classes except GMM/SM signaling.

R10:

R11 and onwards:


(32 pt makes 2 rows








IP User Data Volume

› Strictly speaking IP user data volume is not an end-user KPI, however in general if the performance of the network improves then the users will be able to transfer a greater volume of data within the same time.

› Also if performance problems are identified using other KPIs then the IP user data volume can be used to evaluate if these are worth fixing.

› In system with low traffic levels it can also be used to as an indication of the statistical significance of deviations found in other KPIs, as a rule of thumb 1 MB of data in the measurement period is needed to have a good statistical significance.

› The counters are technically measuring the LLC data volume rather than the IP data volume, but the LLC overhead is small.


(32 pt makes 2 rows








Summary kpi – Object types

Optimization using OSS

RNO, RPMO and consistency checks


(32 pt makes 2 rows








RNO Application Overview


(32 pt makes 2 rows








RNO - Common Structure

ReportsExport

BSC

RNO Applications

CNA SDM

Recording Definition

RecordingData

CountersChangeOrder

ImplementationData

Collection


(32 pt makes 2 rows








NCS/NOX NCS/NOX FAS/FOX FAS/FOXTET TET MRR MRR

R-PMO R-PMO

NWS-A NWS-A NWS-A

MTRCTRCER

RNO

Planning Tuning Troubleshooting

R-PMO

PMR

NWS

Network optimization tools


(32 pt makes 2 rows








BFRBFR : Basic Recording Framework (25 corba processes)

FASFAS : Frequency Allocation Support

RNDBI RNDBI : RNO Database

Export Interface

Optimizing Neighboring Cell Tuning

MRRMRR : Measurement

Result Recording

WNCSWNCS : WCDMA

Neighboring Cell Support

WMRRWMRR : WCDMA

Measurement Result

Recording

S

F

F

Function Function Function

F

F

NCSNCS :Neighboring Cell Support

(NCS-G) F

FOXFOX : Frequency

Optimization Expert

SYROXSYROX : Synchronized Radio Network Optimization

Expert

F S

SSSS

S

NOXNOX : Neighboring

Cell List Optimization

Expert

TETTET : Traffic Estimation

Tool

GWNCSGWNCS : GSM

WCDMA Neighboring Cell Support

F F

(NCS-GW)

F S S

File database

Sybase database

RNO, Radio Network Optimization – Function group


(32 pt makes 2 rows








BFRBFR : Basic Recording Framework (25 corba processes)

FASFAS : Frequency Allocation Support

RNDBI RNDBI : RNO Database

Export Interface

Optimizing Neighboring Cell Tuning

MRRMRR : Measurement

Result Recording

WNCSWNCS : WCDMA

Neighboring Cell Support

WMRRWMRR : WCDMA

Measurement Result

Recording

S

F

F

Function Function Function

F

F

NCSNCS :Neighboring Cell Support

(NCS-G) F

FOXFOX : Frequency

Optimization Expert

SYROXSYROX : Synchronized Radio Network Optimization

Expert

F S

SSSS

S

NOXNOX : Neighboring

Cell List Optimization

Expert

TETTET : Traffic Estimation

Tool

GWNCSGWNCS : GSM

WCDMA Neighboring Cell Support

F F

(NCS-GW)

F S S

File database

Sybase database

RNO, Radio Network Optimization

2G Cell => 2G Cell

2G Cell => 3G Cell

3G Cell => 3G Cell


(32 pt makes 2 rows








RNO – System Parameters


(32 pt makes 2 rows








Recording Session


(32 pt makes 2 rows









Site location and antenna information

The function of FAS, NCS, GWNCS, FOX and NOX depends on information about the geographical position, antenna type, and direction of cell antennas.


(32 pt makes 2 rows








MRR – Measurement Result Recording


(32 pt makes 2 rows








Supervision

NetworkPerformance

Implementation

CNA

Verification

Compare Radio Characteristics

before and after change of parameters

Analysis

Signal Strength

Signal Quality

Ms Power level

BTS Power Reduction

Timing Advance

(Path loss)

MRR - Optimization


(32 pt makes 2 rows








Finding the Effects of a Change

Order a recording for the

area of the network

that will be changed

Switch on, for instance,

DTX in the BSC

Order a new Recording

after one or a few days

Open the Comparison Report check if Quality and

Performance have improved


(32 pt makes 2 rows








MRR Report Preferences

RXQUAL UL (0 ..7 GSM)

RXQUAL DL (0 ..7 GSM)

RXLEV UL (0 .. 63 GSM, -110,5 .. -47.5 dBm)

RXLEV DL (0 .. 63 GSM, -110,5 .. -47.5 dBm)

Path Loss UL (30 .. 153 dB)

Path Loss DL (30 .. 190 dB)

Path Loss Difference (-25 .. 25 dB)

Timing Advance (0 .. 219 GSM)

Power Reduction BS (0 .. 30 dB)

Power Level MS (0 .. 39 dBm)

FER UL (0 ..96 GSM)

FER DL (0 ..96 GSM)


(32 pt makes 2 rows








MRR Report Preference


(32 pt makes 2 rows








MRR- some definitions examples

Interference level definition

(Sample number of RxLev>=-80dBm and RxQual>=4)/total samples

Worst Coverage(Sample number of RxLev<-90dBm on Downlink and TA<=1)/total samples*100% is more than 30%.

Overlapping CellsSample number of RxLev>-80dBm on Downlink and TA>1/total samples*100% is more than 20%.


(32 pt makes 2 rows








Using MRR for comparison Before & After

• Signal strength in both Uplink (UL) and Downlink (DL)

• Signal Quality in both UL and DL

• Timing Advance (TA)

• Power level used by the MS and Power reduction of the BTS

• UL and DL Pathloss

• Pathloss difference (Pathloss DL - Pathloss UL)

• Frame Erasure Rate (FER) in both UL and DL


(32 pt makes 2 rows








The cell carries traffic for TA=32. Check if this is consistent with cell plan (map)

Cell covers too much (TA - recording)


(32 pt makes 2 rows








Supervision

HO attempts

-success rate

-reversions

-failures

Implementation

CNA

Verification

Improved Handover statistics

Analysis

Ranking of

HO candidats

Compare defined NR

with Test frequencies

NCS/NOX - Optimization


(32 pt makes 2 rows








NCS - Important Recording Parameters


(32 pt makes 2 rows








Active BA-list Recording

Serving Cell

BCCH 35BSIC 12

BCCH 35BSIC 12

BCCH 37BSIC 23

BCCH 37BSIC 23

Undefined Neighbour Cell

Defined Neighbour Cell

Transmit Active BA-list(35, 37, 33)

Mobile listen for BCCH 35, 37, 33

BSCBSC

BCCH 33BSIC 17

BCCH 33BSIC 17

Test frequency


(32 pt makes 2 rows








NCS - Cell Report


(32 pt makes 2 rows








NCS - Change Order

NCS Cell Report

NCS Change order

Cell ACell BCell X

Add Neighbour toChange order Export to CNA

planned area

Update network


(32 pt makes 2 rows








NOX - Change Order Recommendation


(32 pt makes 2 rows








FAS/FOX - Frequency allocation support/ expert

Interference Signals on the uplinkInterference Signals on the uplink

Interference Signals on the downlinkInterference Signals on the downlink


(32 pt makes 2 rows








Supervision

Interference level

Drop rate

Speech Quality

Implementation

CNA

Verification

Compare Interferenceafter change offrequency plan

Analysis

UL: Interference

distribution

DL: ICDM, PIT

FAS/FOX - Optimization


(32 pt makes 2 rows








FAS/FOX

How to see uplink How to see uplink Interference ?Interference ?

• TRX measures the uplink interference repeatedly on configured and test frequencies

• Samples every 15 sec

• Use RIR function in BSC


(32 pt makes 2 rows








No of Samples

Interference (dBm)

50 th percentile (median)

I= -105 dBm I= -75 dBm

90 th percentile

Percentile: Tells the value I dBm below which x% of the samples fall x th percentile

I (dBm)

Distribution of uplink interference


(32 pt makes 2 rows








FAS/FOX

How to see downlink How to see downlink Interference ?Interference ?

• Measurement Reports from MS on configured and test frequencies are collected

• ICDM & PIT are computed to give estimation of downlink interference

• Use BAR function in BSC


(32 pt makes 2 rows








Interference

9600143

dB

A

C

Carrier, f1CA

<0 dB

Distance

Adjacent, f2f2 = f1 ± 200 kHz

Co-channel

9600142

dB

C

I

Carrier, f1

CI

>0 dB

Distance

Interferer, f1

Adjacent channel

C/I > 9 dB (GSM specification)

C/I > 12 dB (Ericsson recommended)

C/I > 9 dB (If Fq. hopping is used)

C/A > -9 dB (GSM specification)

C/A > 3 dB (Ericsson recommended)


(32 pt makes 2 rows








FAS - Important Recording Parameters


(32 pt makes 2 rows








FAS - Cell Report


(32 pt makes 2 rows








• Shows how much one specific cell interferes other cell

• ICDM is used to compute PIT values

• ICDM can be imported to TCP to simulate downlink interference instead of predicted data

ICDM - Inter Cell Dependency Matrix


(32 pt makes 2 rows








• Estimation of downlink interference

• Calculated for all frequencies in all cells

PIT - Percentage Interfered Traffic


(32 pt makes 2 rows








FOX - Change Order Recommendation


(32 pt makes 2 rows








TET - Traffic Estimation Tool

????Hot Spot Finder

Off-load

Off-loadOff-load

RPMO and TEMS Visualization


(32 pt makes 2 rows








SQL Database

BSC

OSS RC 5

R-PMO

REDE Files

EBA

Database

The data flow in EBA

RNXDB

EBS

External Post processing tools

e.g. Exel

STS, NWS/ENIQ

FFAD

BO reports

EBS database

TEMSVisualization

RTT

RTED

RPDBI

RTT

FFAX


(32 pt makes 2 rows








Time

0 10 50403020

E2E1

RTED - Real Time Event Data

E3 E5E4

MR MRMR

MRMR

MRMR

MR

MRMR

MRMR

…MR

MRMR

MR

Signaling TCH HO HODropped call

OSSR-PMO Agent

Event Data

R-PMO ClientDisplay monitors


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MRR…….SupervisionNWS

TrafficQuality

Drop rateHandover perf.

………

Implementation change

CNA

Verification R-PMO

Fast feedback to network

changes

AnalysisR-PMO

Short term trendsDrop rate

Handover stats.TCH utilizationSpeech Quality

etc.TEMS Visualization

Detailed analysisFollow calls

R-PMO – In the optimization process


(32 pt makes 2 rows








KPI measurements for CSUsing R-PMO

Retainability

Accessibility

Serv

ice

Inte

grityQuality

ofService

TCH (time) Congestion

Call attemptsTCH/SDCCH

Utilization

Handover SuccessHandover lost

Subcell changes

Dropped callsRXQUAL

SQI

FER

…and much more…


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KPI measurements for PS trafficUsing R-PMO

Interference

Capacity

Mob

ility

Qualityof

ServiceBLER

RL Bitra

te

BEP/RXQUAL

BEP/RXQUAL at Cell

Change

…and much more…

# PDCHs

Multislot

capability

PreemptedPDCHs Ave. TBF time

Cell reselectionsCRS Outage

time

Flush messages


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R-PMO GUI overview

Drag & drop

Drag & drop

1

2

3


(32 pt makes 2 rows








R-PMO main window


(32 pt makes 2 rows








TCH Drop Report – Bad Quality

Drag & drop

1

3

4

2

5


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Create user defined Bad Quality report

Drag & drop

1

3

42


(32 pt makes 2 rows








Detailed trouble shooting- on call level exporting raw events in a REDE file

Drag & drop

1

3 4

2


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Initiate REDE

1. Define cell set (max 5 recordings with 100 cells/rec)

2. Define events and monitors to include in the recording

3. Select Text, XML or binary format, if the file should be compressed and the time

4. Click Start!


(32 pt makes 2 rows








Schedule REDE

› It is also possible to schedule a REDE session


(32 pt makes 2 rows








REDE file output

› A REDE session will produce an xml, txt or bin file depending on chosen file type.

› The output directory will be:– /var/opt/ericsson/eba_rede/data/<user>/rawEventExport– /var/opt/ericsson/eba_rede/data/<user>/scheduledRawEventExport


(32 pt makes 2 rows








TEMS Visualization Data Flow

GPEHMain window

OSS RCApplication server

R-PMOParser

PC with TEMS Visualization

File system

BSC

RNC

R-PMOMain window

GPEH Parser

WCDMA Module

GSM Module

GS

MW

CD

MA


(32 pt makes 2 rows








GSM – Handover Causes for R11


(32 pt makes 2 rows








GSM – Extended Drop Causes

Traditional Drop CausesEXCESSIVE TASUDDENLY LOST CONNECTIONLOW SS BOTHLINKLOW SS DOWNLINKLOW SS UPLINKBAD RXQUAL BOTHLINKBAD RXQUAL DOWNLINKBAD RXQUAL UPLINKNO URGENCY CONDITION

Extended Drop Causes (R12)A-INTERFACE TERRESTRIAL RESOURCE UNAVAILABLEA-INTERFACE TERRESTRIAL RESOURCE ALLOCATEDA-INTERFACE SCCP DISCONNECTION INDICATIONA-INTERFACE RESET CIRCUIT FROM MSCA-INTERFACE TERRESTRIAL RESOURCE FAILUREHW TRANSCODER RESOURCE FAULTHW EQUIPMENT FAILUREHW GS FAULTAIR INTERFACE T200 EXPIREDAIR INTERFACE UNSOLICITED DM RESPONSE IN MULTIPLE FRAME ESTABLISHED STATEAIR INTERFACE SEQUENCE ERRORAIR INTERFACE EXCESSIVE TAAIR INTERFACE TOO MANY MEASUREMENT GENERATIONS MISSINGAIR INTERFACE MS LOSTAIR INTERFACE TOO MANY MEASUREMENT GENERATIONS MISSING AND EXCESSIVE TAAIR INTERFACE CONNECTION FAILURE TO MS AT HANDOVERATER TRANSMISSION SETUP FAILURE RESOURCE NOT AVAILABLEATER TRANSMISSION SETUP FAILURE TIMEOUT ON ATERATER SCCP CONNECTION FAILUREATER RESET CIRCUIT FROM TRCATER TERRESTRIAL RESOURCE FAILUREOTHER OPERATIONAL RECOVERY FAILEDOTHER PREEMPTIONOTHER THE BPC IS BEING CREATED OR IS ABOUT TO BE DELETEDOTHER RECONFIGURATION OF BTS EQUIPMENT 1OTHER RECONFIGURATION OF BTS EQUIPMENT 2OTHER TAS SYSTEM ERROROTHER TRXC FAILUREOTHER TGC CHANGEOVER FAILUREOTHER NO RADIO RESOURCE AVAILABLEOTHERABIS LAPD LINK DISTURBANCEABIS LAPD LINK FAULTABIS TRA OR TRANSMISSION DEVICE FAULTABIS BTS FAULT REPORT CLASS1ABIS TRANSMISSION FAULURE


(32 pt makes 2 rows








TEMS Visualization - Main window

1

3

2


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Raw Event Data Export file – Post process

1

2


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Post process – Recording file info

13

2


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Post process – Recorded cell list, detailed analysis of TCH drop in Cell 4012C, list TCH dropped calls

1

3

4

2


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Post process – Detailed analysis of call ID 3606 call messages list

1

3

4

2


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Post process – Detailed analysis of call ID 3606measurements display e.g RXLev, RxQual

1

2

3


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Time slot monitoring – Replay of 1 hour recording of Cell 4117A

1

3

2

5

64

3


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Import Data


(32 pt makes 2 rows








Call List View

In the Call List it is possible to view call data of selected callsE.g. termination cause, drop cause, duration, handovers etc.

Double-click if you like to follow the call


(32 pt makes 2 rows








Call Messages and Detail ViewC

all

mes

sage

s

Mes

sage

de

tails


(32 pt makes 2 rows








Measurement Result Viewer


(32 pt makes 2 rows








Timeslot Monitor View


(32 pt makes 2 rows








Map View - Estimated positioning


(32 pt makes 2 rows








Advanced Search› Search the database for ping-pong handovers or dropped calls after

handover


(32 pt makes 2 rows








Time Difference Histogram› Analyze the time difference between any two events in the database–What is the call setup time for a voice call?–What is the average time for a successful handover?


(32 pt makes 2 rows








Distribution Chart


(32 pt makes 2 rows








Scatter ChartAnalyze scatter data for all data points for selected cell or from calls in the call list


(32 pt makes 2 rows








Cell Performance Report


(32 pt makes 2 rows








Download - GSM Performance KPI Optmization

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