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Analysis of Feature 72 HSPA users activation on 13 WBTS

Sadok Ben Ali

2 ©2013 Nokia Solutions and Networks. All rights reserved.

HSDPA Drop Rate

72 HSPA Users activation

There is increase of 0.1 drop rate

It was pick on HSPA Drop Rate, was due to TUN4044, is back to normal on 19th

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HSDPA drop per layer

Only F0 layer is impacted, drop rate on U2100 cells remains stable

Graph above shows F0 Cells having increase on HSDPA Drop Rate. Mainly the drop increase for the most HSUPA users loaded cells

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Trace TUN4125 – RL Fail for HSDPA Inetractive

Based on the trace most of drop on U900 cells was due to synchronization lost between UE and NodeB in the good radio condition (on this case RSCP = -80 dBm, EcNo = -6dB). It seems that the synchronization lost was due to uplink load/interference

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UL Load Analysis for TUN4125 – Hourly Stats

Class 17 (-83 dBm <=RTWP< -80 dBm). Class 16 (-86 dBm <=RTWP< -83 dBm).

Based on stats there is increase of high RTWP (UL load) classes for U900 cells after activation of 72 HSPA users due to increase of simultaneous HSUPA users

The HSUPA physical channel power has been incresed by 8 dB, means that the interference is become high and UE is required to send with higher power.The graph shows that U900 is highly interfeered compare to U2100

HSUPA physical channel power

High number of HSUPA simultanious users on U900 cells compare to U2100 cells

RTWP/UL load

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UL Load per layer – Cluster level

U900

U2100-F1

U2100-F2

High number of samples of excessive UL load on U900 compare to U2100 which is causing high UL interference. This could be reason behind drop increasing

Class 19 (-75 dBm <=RTWP< -70 dBm).Class 20 (-70 dBm <=RTWP< -65 dBm).Class 21 (-65 dBm <= RTWP).

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Conclusion

• High number of samples of excessive UL load on U900 compare to U2100 which is causing high UL interference. This could be reason behind drop increasing

• The increase of HSUPA simultaneous users will generate more interference and RTWP spikes which cause the increase of drops.

• Mainly is U900 cells are impacted since this layer is more sensitive to the interference, is designed to support traffic in bad quality, it is already loaded and it is the layer supporting higher simultaneous users compare to U2100 cells(56 users in case of TUN4125f03)

Recomendation :• We should balance traffic between layers• Activate Prfile parameters : HSUPA Initial SIR target as is recommended in TS159• Activae feature HSUPA Interference Cancelation