Radio Link Timer (RLT) explanation ??

[fahmi]

Hi experts,
Please could you explain waht a RLT does mean ?
Which values does this parameter take ?
How to get and change this value for huawei vendor ?
thanks a lot :)

[helper]

this parameter determine when the RL has to be released in downlink..

it defined with the SACCH periods.

it is very sensitive parameter oN call drop. you can qurry with the command LST Gcellccbasic
This parameter specifies when an MS disconnects a call if the MS unsuccessfully decodes the SACCH message. For details of this parameter, see GSM Rec. 0408 and 05.08.
Once a dedicated channel is assigned to the MS, the counter S is enabled and the initial value is set to this parameter value.
Each time an SACCH message is not decoded, the counter S decreases by 1. Each time an SACCH message is correctly decoded, the counter S increases by 2.When the counter S is equal to 0, the downlink radio link is considered as failed.Therefore, when the voice or data quality is degraded to an unacceptable situation and it cannot be improved through power control or channel handover, the connection is to be re-established or released.

Dont modify this parameter unnecessarily. mostly it deals with the customer contactual parameters..

Please add rep if it Is useful for you,...

[manythanks]

wil it work for UPlink as well?



this parameter determine when the RL has to be released in downlink..

it defined with the SACCH periods.

it is very sensitive parameter oN call drop. you can qurry with the command LST Gcellccbasic
This parameter specifies when an MS disconnects a call if the MS unsuccessfully decodes the SACCH message. For details of this parameter, see GSM Rec. 0408 and 05.08.
Once a dedicated channel is assigned to the MS, the counter S is enabled and the initial value is set to this parameter value.
Each time an SACCH message is not decoded, the counter S decreases by 1. Each time an SACCH message is correctly decoded, the counter S increases by 2.When the counter S is equal to 0, the downlink radio link is considered as failed.Therefore, when the voice or data quality is degraded to an unacceptable situation and it cannot be improved through power control or channel handover, the connection is to be re-established or released.

Dont modify this parameter unnecessarily. mostly it deals with the customer contactual parameters..

Please add rep if it Is useful for you,...

[helper]

Nope.. there is another parameter for Uplink, it differs for AMR as well as normal call.. and it is also defined in Sacch period..

[dacoder]

For Uplink you need to use this parameter:
SAMULFRM (SACCH Multiframes)

Modify it using this command : SET GCELLCCBASIC

[wireless_houss]

Hi experts,
Please could you explain waht a RLT does mean ?
Which values does this parameter take ?
How to get and change this value for huawei vendor ?
thanks a lot :)

The MS originates call resetup or disconnects by force if all the following conditions are met:


The voice or data quality is too poor to be received.
Power control and handover cannot help to improve the quality.

A disconnection by force actually brings about a call drop, so the MS considers it a radio link failure that the voice or data service is actually too poor to be received. GSM regulations provide solutions to the previous problems as follows:
Set a counter S in the MS. The initial value of S is provided at the beginning of talk, and it is the value of the parameter radio link failure counter. S changes as follows:


S decreases by 1 if the MS fails in decoding a correct SACCH message when the MS should receive the SACCH message.
S increases by 2 if the MS succeed in decoding a correct SACCH message.

S cannot exceed the value for radio link failure counter. When S equals to 0, the MS originates call resetup or disconnects by force, as shown in Figure

25409

Proper configuration of radio link failure counter is important, and is related to the actual situations. To configure radio link failure counter, refer to the following rules:
l Configure it to between 52 and 64 in areas with over low traffic.
l Configure it to between 36 and 48 in areas with low traffic and great coverage radium
Configure it to between 20 and 32 in areas with heavy traffic

[Budaxbaix]

Increase RLT can reduce call drop. the trade off is user experience due to user will try to disconnect manually after the call going bad, so it will not count as call drop.
The setting should be discussed with customer base on several condition like Urban, suburban, or rural area.