N-300 and T-300 timer expiry

[tsiz]

All,

How do we fix blocked calls on site with N-300 and T-300 timer expiry?

Call is placed and Ue retry the attempts 3-4 times but ends up with blocked call due to the timer expiry.

Any help would be appreciated!

Thanks.

[twenty8]

Hi,
N300 and T300 controls the time the number of RRC Conn Request is send from UE side. What is the current values being used in the network. Also , check in what type of enviroment is this send, the problem could either be limited UL coverage or high interference in case of pilot pollution. It possible to extend these values , but need to know what you are using now.

[tanbao]

All,

How do we fix blocked calls on site with N-300 and T-300 timer expiry?

Call is placed and Ue retry the attempts 3-4 times but ends up with blocked call due to the timer expiry.

Any help would be appreciated!

Thanks.

N300: number of retry (in 3GPP is 3; in E/// is 5)
V300: current number of retry
T300: Timer between each retry.

When these parameter expire, you should find out why block call (Mp load, lack dl code, lack channel element,....)

[tsiz]

N300: number of retry (in 3GPP is 3; in E/// is 5)
V300: current number of retry
T300: Timer between each retry.

When these parameter expire, you should find out why block call (Mp load, lack dl code, lack channel element,....)

It does not give a message..or a RRC connection reject because of congestion or something..

How do i find out what is the reason?

[tsiz]

Hi,
N300 and T300 controls the time the number of RRC Conn Request is send from UE side. What is the current values being used in the network. Also , check in what type of enviroment is this send, the problem could either be limited UL coverage or high interference in case of pilot pollution. It possible to extend these values , but need to know what you are using now.

They are supposed to be the standard parameter set..other sites have no issues..only this one site.

[tanbao]

They are supposed to be the standard parameter set..other sites have no issues..only this one site.

Please check the counter and drive test analysis

[twenty8]

Hi, basically this is the number of times the UE can make a RRC Conn Req after the user places a call, on expiry of the number of times, the UE will report a failure and end the attempts for RRC.

From counters you can check the RRC Sucess Rate for this cell, also I imagine you are seeing this problem from dt logs ? do you still get this problem when you are close to the site ?

[jan74]

All,

How do we fix blocked calls on site with N-300 and T-300 timer expiry?

Call is placed and Ue retry the attempts 3-4 times but ends up with blocked call due to the timer expiry.

Any help would be appreciated!

Thanks.

This can happen for several reasons but in my experience, the main reason is Hardware Fault at the Node B. Check stats on that site for RRC Conn Setup SR. I would reset the site and try again and failing that, get HW checked.

[gogotchiya83]

thanks Jan for your answer,
Can you explain me the reason of the RRC drop? i have a huge RRC drop in our network (more than 20%) even with a good CSSR (AMR, PS_R99, HSDPA)...
another anomaly is the PS_R99 drop Call (3%) even the DCR_AMR=0.3% and DCR_HSDPA = 0.5%
any relationship between these two indicators? (RRC drop and PS_R99 drop)?
so what is the reason ?

[jan74]

thanks Jan for your answer,
Can you explain me the reason of the RRC drop? i have a huge RRC drop in our network (more than 20%) even with a good CSSR (AMR, PS_R99, HSDPA)...
another anomaly is the PS_R99 drop Call (3%) even the DCR_AMR=0.3% and DCR_HSDPA = 0.5%
any relationship between these two indicators? (RRC drop and PS_R99 drop)?
so what is the reason ?

Well in many cases, the RRC Drop Counter will also be triggered when you drop your RAB, unless you manage to re-establish synchronisation with the network. Do you have RRC Re-Establishment for NRT enabled? Check the counters to see its working correctly. 20% is really huge for RRC Drops. Have you got problems with registrations?

Check that its not just one or 2 sites that are causing this as this can happen when you have a dodgy card in a Node B. If you have this across the board, its either a parameter that is not set correctly in the RRC process or you have an RNC fault. Check what the RRC Drop Causes are. Also, how are your SHO stats?