9 Omo233020 Bsc6900 Gsm v9r11r12r13 Traffic Statistics Issue 1.02

7/27/2019 9 Omo233020 Bsc6900 Gsm v9r11r12r13 Traffic Statistics Issue 1.02

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GSM Traffic Statistics















A large number of measurement counters exist in the M2000 system. Therefore, the

counters are divided into different levels for better and efficient management.

Level 1: function set. A function set consists of multiple function subsets related to

a specific system function. Function sets are also called measurement sets.

Level 2: function subset. A function subset consists of measurement counters

related to a certain system function. Function subsets are also called measurement

units.

Level 3: measurement counter.





According to sources, measurement counters are classified into two types:

System counters: defined by NEs, NEs periodically report the measurement resultsof all system counters to the M2000. System performance counters consist of

default counters and extended counters.

User-defined counters: defined on the M2000 client, namely, custom counters.









BSC Measurement is used to measure the traffic of all the cells controlled by a BSC.









Call measurement refers to the measurement of the call services in the BSC.

Call measurement is the performance during the calling, such as Handover, call drop andassignment; measurement object includes cell, TRX and the LAPD link





The detail description of most of the counters in Call Measurement in M2000 client can be

found in Measurement of GSM Cell Performance(GCELL) in HedEx Lite.





While detail description about GSM Cell to GSM Cell Incoming Handover

Measurement and GSM Cell to GSM Cell Outgoing Handover Measurement can be

found in Measurement of GSM Cell to GSM Cell Performance(GCELL_GCELL) in in

HedEx Lite.





After seizing a specific channel, the MS periodically reports measurement reports (MRs) to

the BSC. The BSC performs power control and handover decision based on the MRs. MR

Measurement refers to the measurements related to MRs and helps with network

optimization.









Analysis process

First we shall analyze and compare the item of BSC measurement function to havea rough idea for the whole network.

During analyzing, if any important items (such as call drop rate or handover success

rate) are abnormal, we shall do further detailed analysis for the corresponding

items.









Location:

[BSC6900 GU]

[MR Measurement]

[Interference Band Measurement per TRX] The interference band thresholds could be changed from LMT/MML.





This measurement provides the average number of idle channels (TCHF, TCHH, or SDCCH)

whose interference level are in each interference band (1-5) per granularity period.

Measurement Point

The system accumulates the number of idle channels (TCHF, TCHH, or SDCCH)

whose interference level are in each interference band every five seconds. At the

end of a granularity period, the accumulated number is divided by sampling times.

The result is the average number of idle channels (TCHF, TCHH, or SDCCH) whose

interference level are in each interference band.









Besides use “interference band” to identify the interference , we can use

function ”Frequency Scan”:

Step1: After login LMT, lick “Device Maintenance”.

Step2: Right click any cell in “Device Navigation Tree”, and select “Configure Frequency

Scan”, then pop out the “Configure Frequency Scan” dialog box, check any ARFCN needed

according to the practical and set the “Hour” and “Minute” you want(for example 5

Minutes), and click “Start”, and then click ”Cancel” to close the dialog box.

Stpe3:Right click the same cell in “Device Navigation Tree”, and select “Query Frequency

Scan”, then pop out the page named “Query Frequency Scan”. After 5 minutes, there is

receive level output for all the ARFCNs checked before, shown as following. Usually, we

care both “Main Average” and “Sub Average”.





Location:

[BSC6900 GU]

[MR Measurement]

[TCHF(H) Receive Level Measurement perTRX]









Receive Level Measurement, together with Receive Quality Measurement per TRX, reflects

the radio signal coverage and interference of a cell. For example, a high ratio of high level

and low quality suggests there may be interference; a high ratio of low level and low

quality suggests poor coverage. This helps to locate the faults in the TX/RX channel, such

as the TRX and the antenna.









Location:

[BSC6900 GU] [MR Measurement] [Uplink-and-Downlink Balance Measurement per

TRX]

In an optimum system, power should be well estimated in design to enable the balance

between the coverage of uplink signals and the coverage of downlink signlas. If the coverage of

uplink signals is wider than the coverage of downlink signals, the downlink signals at the cell

edge are weak and easy to be overwhelmed by strong signals in other cells. If the coverage of

downlink signals is wider than the coverage of uplink signals, the MS has to camp on the cell

with strong signals; however, the uplink signals are weak and the speech quality is poor. The

balance does not refer to the absolute balance. The MR on the Abis interface can be used to

check whether the coverage of uplink signals and the coverage of downlink signals are inbalance.





Mapping between the uplink/downlink balance rank and the receive level.

The MR received by the BSC contains the uplink receive level and the downlink receive level. The

uplink/downlink balance factor is calculated through the following formula. The results in dB aregraded from levels 1 to 11, and the number of MRs of each level is calculated.

The formulas are as follows:

Uplink/downlink balance = uplink path loss - downlink path loss

= (actual TX power of the UE - uplink receive level) - (TRX power on top of the cabinet -

downlink receive level)

TRX power on top of the cabinet = TRX initial power - TRX power level x 2 + Power Finetune-

Combiner Loss - downlink dynamic power control level x 2 + dynamic PBT gain

Where: TRX initial power: the power corresponding to the TRX power type, expressed in dBm;

Power Finetune: power fine tune of the TRX; it can be configured by command SET

GTRXDEV (Optional)

Combiner Loss: combination loss of the cell x (0.1); it cab be configured by SET

GCELLPWRBASIC (Optional)

Dynamic PBT gain: if the dynamic PBT function is enabled in the call, the dynamic PBT

gain is 3 dB; otherwise, the dynamic PBT gain is 0 dB.

Dynamic PBT function is enable or not: parameter “Dynamic Transmission DivSupported” is “DPBT(DPBT)”by command SET GCELLCHMGBASIC and parameter

“Send Mode” is “DPBT(DPBT)”by command SET GTRXDEV.





Location:

[BSC6900 GU]

[MR Measurement]

[Uplink-and-Downlink BalanceMeasurement per TRX]

If the balance between the uplink and the downlink is mainly at level 1, you can infer that

the downlink loss is too great or the downlink transmit power is too small. If the balance

between the uplink and the downlink is mainly at level 11, you can infer that the uplink

loss is too great or the uplink transmit power is too small. The balance level helps to locate

the faults in the TX/RX channel, such as the TRX and the antenna.





Location:

[BSC6900 GU]

[MR Measurement]

[Measurement of Power Control Messagesin MR per Cell]

Power Control Messages per Cell refers to the measurement of the transmission power

and the receive level between the BTS and the MS. It can measure the coverage of cell and

the receive level or quality average.





MR Measurement ->Neighbor Cell Level Measurement per Cell

The measurement unit is used to measure the mean receive level of the neighbor cell. Youcan determine whether to configure the neighbor relation based on this measurement.

When measuring the information of defined neighbor cells, the measurement unit is used

to measure the redundant cells. When measuring the information of undefined neighbor

cells, the measurement unit is used to measure the miss-configured cells. It is

recommended to register the NCELL when deploying a new site and delete the NCELL of

the cells after network optimization. Register less than 50 cells, or the CPU usage of the

XPUM will increased by 10% to 20% at traffic peak.





Location:

[BSC6900 GU]

[MR Measurement]

[Neighbor Cell Level Measurement per TRX] The measurement unit provides the mean receive level of the neighbor cell.

When measuring the information of defined neighbor cells, the measurement unit provides

the redundant cells. When measuring the information of undefined neighbor cells, the

measurement unit provides the miss-configured cells. It is recommended to register the

NCELL when deploying a new site and delete the NCELL of the cells after network

optimization. Register less than 50 cells, or the CPU usage of the XPUM will increased by

10% to 20% at traffic peak.





Location:

[BSC6900 GU]

[Call Measurement]

[KPI Measurement per Cell]









Location:

[BSC6900 GU]

[Call Measurement]

[GSM Cell to GSM Cell Outgoing HandoverMeasurement ]





HO Type HO cause

No MR. HO

Uplink Quality TA HO Timing Advance

Bad Quality HO Uplink/Downlink Quality

Interference HO Other Causes (HO AlgorithmⅠ); CH3036A Internal Intra-Cell

Handover Requests due to Uplink Intervention/ CH3036B Internal Intra-Cell

Handover Requests due to Uplink Intervention (HO Algorithm Ⅱ)

Edge HO Uplink/Downlink Strength

PGBT HO Better Cell

MS Fast Moving HO Other Causes

Layer HO Better Cell

Load HOLoad

Enhanced Dual-band HO Underlaid to Overlaid Subcell Handover in Enhanced

Dualband Network/ Overlaid to Underlaid Subcell Handover in Enhanced Dualband

Network/ MS Handover in the Overlaid Subcell Covered by the Enhanced Dualband

Network





Location:

[BSC6900 GU]

[Call Measurement]

[GSM Cell to GSM Cell Incoming HandoverMeasurement ]









Location:

[BSC6900 GU]

[Call Measurement]

[Intra-cell Handover Measurement per Cell]









Location:

[BSC6900 GU] [Call Measurement] [Call Drop Measurement per Cell]

ERR IND

After the MS seizes a channel, the BTS sends the BSC an ERR IND message,

indicating that call drops occur on the Um interface because of the abnormal

connection at the radio link layer.

If the cause value carried in the ERR IND message is timer T200 expired (N200+1)

times (0x01), unsolicited DM response (0x04), or sequence error (0x07), this

measurement provides the number of call drops due to ERR IND on the basis of the

channel type (SDCCH, TCHF, or TCHH), the service type (signaling or traffic), the

concentric attribute (overlaid subcell or underlaid subcell), and the cause value. CONN FAIL

After the MS seizes a channel, the BTS sends the BSC a CONN FAIL message,

indicating that call drops occur on the Um interface because of the abnormal

connection at the radio link layer.

If the cause value carried in the CONN FAIL message received by the BSC is radio

link failure (0x01), handover access failure (0x02), om intervention (0x07), or radio

resource not available (0x21), this measurement provides the number of call drops

related to CONN FAIL IND on the basis of the channel type (SDCCH, TCHF, or

TCHH), the service type (signaling or traffic), the concentric attribute (overlaid

subcell or underlaid subcell), and the cause value.





REL IND

The connection between the MS and the BTS fails. Therefore, when the BTS in the

multi-frame link set-up state receives the DISC frame from the MS, the BTS sends

the BSC an RELIND message indicating that call drops occur on the Um interface.

No MRs from MS for a Long Time

If the BSC does not receive a measurement report within a certain period (five

minutes by default), the BSC determines that a call drop occurs on the Um

interface.

Abis Terrestrial Link Failure

After the MS seizes a channel, the call may be released because the RSL of the TRX

carrying the channel is broken.

Equipment Failure

After the MS seizes a channel, the call may be released because of the internal

error of the BSC.

Forced Handover

After an MS seizes a channel, if the system initiates a forced handover and the

handover fails, the BSC may initiate a call release procedure.

Resource Check

This counter is measured when the call is released due to the inconsistency in the

check for the internal resources of the BSC.





Location:

[BSC6900 GU]

[Call Measurement]

[AMR Service Measurement per Cell] The BSC measures these counters when receiving the SETUP or CALL CONFIRMED message

that contains the speech version.

It indicates penetration of AMR MS.










9 Omo233020 Bsc6900 Gsm v9r11r12r13 Traffic Statistics Issue 1.02

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