Tuesday, 22 September 2015

LTE FDD Network Planning & Optimization System-LTE Found overshooting problem By TA counter

Incident Description (Incident Phenomena)
The RRC drop times of site 7861 suddenly increased much at 12am, 2015-02-17. The main failure reason is from radio link failure.
 Networking Environment
 Problem Cause Analysis
1)      Check alarms: RRU link break alarm. After alarm clear, the KPI didn’t back.

2)      Check the parameters: No parameter changed.
3)      Check RSSI counters: Normal.
4)      Check TA counters: TA counter is abnormal. This site has overshooting problem.
Compared with the TA counter of yesterday, we found the TA distribution changed much.

The TA distribution changed much, and radio parameter is no any change. So we can judge there are some things happened in antenna. (Antenna height, antenna downtilt…)
After checked on site, we found the antenna was be swapped from Mobi to Andrew. And the antenna downtilt didn’t follow previous setting.
After we set the antenna downtilt to previous value, the KPI back well.

 Summary and Notes
TA counter can represent the distance of UE to eNodeB. It is a good tool for our RF optimization work.
Through the TA value, we can know more information of the cell coverage, and thus we can be more targeted for parameter adjustment.

Budi Prasetyo

About Budi Prasetyo

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