MACEPARA_MACHSPARA_RTWP.pdf

in NPI project in Operator X, the customer asked us to optimize the HSDPA mean channel throughputfirst we needed to understand the different factors affecting the HSDPA throughput:

-number of concurrent users -number of available codes -available power -radio conditions

the radio conditions that affect the HSDPA throughput are the RTWP and CQI, so even if there's no limitation on the code and power if the RTWP or CQI are bad the user can't get good throughput. so we searched for a way to optimize these factors.

NodeB switches were turned on to optimize the measurement of CQI and RTWP as follows:

1- RTWPMEAOPTIMSWITCH

Overview

When this switch is set to ON, the impact of short-time random RTWP pluses is filtered out from the measured RTWP value reported by the NodeB to

the RNC, which improves the throughput, and capacity when admission based on ul power is enabled

Activation Script

SET MACEPARA:SCHEDULEPARA=YES,RTWPMEAOPTIMSWITCH=OPEN;

2-CQI Adjustment Based on Dynamic BLER Target

Overview

The CQI measures the channel conditions of a UE and is reported from the UE to the NodeB. Without this feature, the NodeB determines an appropriate

TBS based on the reported CQI, system resources, and the TFRC policy. If the reported CQI and related conditions remain the same, the NodeB does not

change the TBS because it does not consider the ever-changing radio environments.

The constant changes in radio environments, caused by multipath effects and UE mobility, lead to fluctuating channel quality. Under these

circumstances, choosing a TBS based on the reported CQI makes it difficult to always achieve the optimum downlink throughput.

With this feature, the NodeB monitors the channel quality fluctuations for HSDPA users in a cell in real time and dynamically selects a proper BLER target

based on the monitoring result. The NodeB then uses the BLER target to adjust the CQI reported by the UE. Based on the adjusted CQI, the NodeB

determines an appropriate TBS to achieve higher downlink throughput for HSDPA users and higher cell throughput.

CQI Adjustment Process.

CQI adjustment based on dynamic BLER target is performed in each TTI. The following describes the adjustment process:

1. Based on the CQI reported by the UE, the NodeB checks the actual radio environment, which is affected by multipath effects and UE mobility. 2. Based on the actual radio environment and channel quality of the UE, the NodeB obtains an optimum BLER target, which helps to achieve the highest

possible throughput for the UE. 3. Based on the ACK, NACK, or DTX indication from the UE in the current TTI and on the optimum BLER target, the NodeB calculates the CQI offset,

which can be a positive or negative number. The NodeB then uses the CQI offset to adjust the CQI. 4. Based on the adjusted CQI, the NodeB selects an appropriate TBS by using the TFRC algorithm

Activation procedure

1- Open the license on NodeB level (CQI Adjustment Based on Dynamic BLER Target)

2- Run the command: SET MACHSPARA:CQIADJALGOFNONCON=CQI_ADJ_BY_DYN_BLER;

After the two switches were opened, the KPIs improved a lot:

-The measured RTWP decreased by filtering out the temporary peaks:

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9/30/2014file://D:\Huawei HCPT MS\03 Complain\Trial Improve HSDPA\HSPA Throughput Optim...

The BLER and retransmissions decreased, where BLER= VS.NackTotal/( VS.NackTotal+ VS.AckTotal+ VS.DtxTotal):

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As a result the HSDPA throughput can reach higher values, and the user experience is improved:

-for each KPI that we need to optimze, we need to check the different factors affecting it, then focus on the ones that have big effect and the ones that

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are easier to control and optimize.

-sometimes it's hard to really improve the radio environment, but we can optimize the way the user perceive and interact with it.

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MACEPARA_MACHSPARA_RTWP.pdf

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