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Idle Mode Behavior

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Low Signal Level

Low Signal Level:In areas where there are few sites and too many different types of terrain

structures like hills or obstacles those stopping the line of sight to the broadcasting signal, theremight be a lot of coverage holes or places with insufficient signal level. Pay attention to thesignificant oscillation on the C/I affected by the drop of signal level

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Lack of Dominant Server

Lack of Dominant Server: Signals of more than one cell can be reaching a spot with low levelcausing ping pong handovers. This might happen because the MS is located on the cell borders and

there is no any best server to keep the call

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Sudden Appearance and Disappearance of Neighbors

Sudden Appearance of Neighbors Terrain Effect: Due to terrain or obstacles, neighbors may popup with high levels causing the BSC to give wrong handover decisions. In this case, there wont be a

stable server, but the call will be handed to the neighbors for very short period

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Fast Moving Mobile

Sudden Appearance of Neighbors Fast Moving Mobile Effect: When MSmoves very fast, thetester will see a lot of handovers and sudden changes on signal levels. This case might happen when

the MSuser is driving fast on the highway. The serving time of the cell will depend on the cell sizeand vary with hierarchical cell structure of the network. There seem to happen too many handoversbut this is due to fast moving mobile

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Sudden Decrease on Signal Level

Sudden Decrease on Signal Level Tunnel Effect: Tester may notice sudden decrease on signallevel when analyzing the log files. This will result in excessive number of handovers. Before

suspecting anything else, check if the test was performed on a highway and that particular area wasa tunnel or not. Signal level on the chart will make a curve rather than unstable changes. Tunneleffect will most likely result in ping pong handovers

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Stable Behavior

Stable Behavior The same Cell serving for a long Time: Looking to above view, tester may thinkthe serving cells coverage is very good and its serving through a long period.

Sometimes this may not be correct and this stable look may result in misunderstanding. Check if thedrive test vehicle was waiting for a red light or any traffic jam causing the vehicle to wait at the samespot for a long time

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Oscillation on Hopping Channels

Oscillation on Hopping Channels Become more Significant with Low Level:Poor coverage bringslow quality and is a very significant sign of future drop calls. Low level on down link signal strength

can mostly occur because of low number of sites in the network, high attenuation from the obstacleslike buildings or hills, or high path loss caused by Rayleigh Fading

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Same Cell in the Neighbor List

The same cell always popping up as the second strongest neighbor in the list through a large areamight show an overshooting cell

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RXLevels too Closed to Each Other

Ss levels of 34 cells are too closed to each other This might point overlapping cells: Other cellselse than the one that suppose to serve at that particular area should becoverage reduced by power

reductions, down tilts or other configuration changes

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RXLevels of Many Cells are almost the same

Signal Strength of All the neighbors are almost the same with each other. This shows the networkneeds big optimization work because there are too many cells having overlapping coverage. This will

cause quality problems because of frequency reuse and immediate action to optimize cell coverageshould be taken

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Line of Sight Lost

Both Signal Strength and SQI are changing fast due to far away server being blocked by obstaclesfrom the terrain. The other way, signal from the server looses line of site to the mobile because of

a hill or something

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Drop Call due to Bad Coverage

Drop Call due to Bad Coverage: Call is dropped because of poor coverage. The signal level goesdown below the minimum signal level that system could carry on