BSC6900 GSM Traffic Statistics ISSUE 1

GSM Traffic Statistics

Confidential Information of Huawei. No Spreading Without Permission

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 results of 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 and assignment; 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 have a rough idea for the whole network.

During analysis, 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, MML COMMAND: SET GCELLOTHEXT.


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, click 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 scenario 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 per TRX]


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 Rx 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


[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 signals'. 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 in balance.


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


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 are graded 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 can be configured by SET

GCELLPWRBASIC (Optional) Dynamic PBT gain: if the dynamic PBT function is enabled in the cell, 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 Div

Supported 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 Balance Measurement 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 Messages in 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. You can 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 configure the NCELL when deploying a new site and delete the NCELL of the cells after network optimization. configure less than 50 cells, or the CPU usage of the XPUM will increase 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 Handover Measurement ]


HO Type HO cause


No MR. HO Uplink Quality TA HO Timing Advance Bad Quality HO Uplink/Downlink Quality Interference HO Other Causes (HO Algorithm ); CH3036A Internal Intra-Cell

Handover Requests due to Uplink Intervention/ CH3036B Internal Intra-Cell Handover Requests due to Uplink Intervention (HO Algorithm )

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 Handover Measurement ]


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.


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.


BSC6900 GSM Traffic Statistics ISSUE 1

Documents

measurement sets

permission bsc measurement

gsm traffic statisticsbe

gsm traffic statisticscounters

measurement results

measurement units

mr measurement

assignment measurement