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guess.who
2009-06-15, 04:57 AM
Hi guyz....i have a query.....
They say , we should use dedicated mode and scan mode in a DT and not idle mode... my question is why not idle mode.... ??
And what is the use of idle mode then if scan and dedicated are that imp...

Thanks in advance
Regards
Guess

cdmahn
2009-06-15, 10:23 AM
You could find the answer in the attached document of Agilent.
Here is one of the main reason.

According to GSM specifications for generating RXLEV measurements, a mobile should take a running average of five samples spread over a period of 5 seconds or the duration of 5 consecutive paging blocks of that mobile, whichever is larger.
To save the battery, MS should monitor Paging Channel (one of the sub-channel of BCH) only in a Paging Channel Group. The duration of these 5 consecutive paging blocks is decided by the BCCH
parameter BS_PA_MFRMS, which informs the mobile of the number of multiframes after which the same paging block is repeated. This can range from 1 to 9 multiframes This means a mobile’s paging block can occur at intervals ranging from 470 ms to 2.1 s. Therefore, 5 consecutive paging blocks for that mobile will occur over a period ranging from 2.35 s to 10.5s. According to GSM specifications, then, the average will be taken over a period ranging from 5s to 10.5s.
With such large time period, the distance between 2 consecutive sample from RxLev should be large (5.5 to 22.5m, depend on BS_PA_MFRMS), and there are some areas that MS doesn't make the measurements. It is a problem for Idle mode measurements if there are problems in such areas.

The scanning samples can be measureed the BCCH carrier with much smaller distance (1 to 5m). That's why scanning method could detect the moblie network coverage problems better that the Idle method.

cdmahn
2009-06-15, 10:25 AM
You could find the answer in some documents about the introduction of drive test measurements.

Here is one of the main reason, according to the document of Agilent (can be found somewhere in this forum).

According to GSM specifications for generating RXLEV measurements, a mobile should take a running average of five samples spread over a period of 5 seconds or the duration of 5 consecutive paging blocks of that mobile, whichever is larger.
To save the battery, MS should monitor Paging Channel (one of the sub-channel of BCH) only in a Paging Channel Group. The duration of these 5 consecutive paging blocks is decided by the BCCH
parameter BS_PA_MFRMS, which informs the mobile of the number of multiframes after which the same paging block is repeated. This can range from 1 to 9 multiframes This means a mobile’s paging block can occur at intervals ranging from 470 ms to 2.1 s. Therefore, 5 consecutive paging blocks for that mobile will occur over a period ranging from 2.35 s to 10.5s. According to GSM specifications, then, the average will be taken over a period ranging from 5s to 10.5s.
With such large time period, the distance between 2 consecutive sample from RxLev should be large (5.5 to 22.5m, depend on BS_PA_MFRMS), and there are some areas that MS doesn't make the measurements. It is a problem for Idle mode measurements if there are problems in such areas.

The scanning samples can be measureed the BCCH carrier with much smaller distance (1 to 5m). That's why scanning method could detect the moblie network coverage problems better that the Idle method.

alkesh
2009-06-15, 01:02 PM
Hi,

The reason for carrying out DT in idle mode is to check the coverage.
This is one of the main reason.

Coverage of BTS is decided by the BCCH power. Hence, proper
coverage can only be examined in idle mode. In Traffic mode,
if there is power control then the measure power will not be
actual power but the controlled power. Hence coverage measurements
are done in Idle mode.

--If i am wrong, please do correct me.

rumy
2010-12-07, 02:18 AM
Hi,

The reason for carrying out DT in idle mode is to check the coverage.
This is one of the main reason.

Coverage of BTS is decided by the BCCH power. Hence, proper
coverage can only be examined in idle mode. In Traffic mode,
if there is power control then the measure power will not be
actual power but the controlled power. Hence coverage measurements
are done in Idle mode.

--If i am wrong, please do correct me.

Hi,

Usually the connected mode is preffered in all systems to measure the coverage. One reason is the measurement is more accurate because you will get more samples in connected than in Iddle due power control (mittigating fading, etc).