Call Drops HO increase with increasing of Half Rate Traffic

[justdream]

Dears,

what's the mean reason (explanantion) behind "Call Drops HO increase with increasing of Half Rate Traffic"..

[plannerguy]

Hi

didnt get you point...


Regards
Plannerguy

[kilisuci_kdr]

IMHO,
When you change from Full Rate to Half Rate or vice versa it needs pack or unpacking.
This condition pack-unpacking is count as handover processing.
So if your system is increasing halfrate condition so is the handover counts that could be more failed as count the drop.

[didemir]

i also couldn't get your point but i was told that when you have more half rate channel and so traffic (for example you don't use automatic full rate to half rate. you use half rate as default) then because of having worse(half) quality, cell will try to send calls to nearest best cell according to quality. that's may be an idea for your question

[usama0795]

By keeping the call at full rate channel SQI is improved and also quality is improved since higher the source bit rate the more impact it would create against bit errors since a large portion of the bit rate is used for channel error protection so Half rate channel should not be used under weak signal conditions, i.e. some calls should fall back to a full rate channel so more redundancy and error correction information can be added to prevent the call from dropping -------------- Additional Info:
The SQI algorithm is based on the bit error rate (BER), the frame erasure rate (FER), the distribution of the FER and BER (e.g. the number of consecutive erased frames), and handover events and so called stolen frames (i.e. speech frames that have been replaced by signaling). Also the currently used speech coder (GSM FR, GSM EFR, GSM HR, AMR, AMR, FR, AMR HR) effects the SQI.The SQI algorithm takes into account all of those parameters and use the built in training to transform this into a speech quality degradation.
A reference scale (dBQ) is constructed by combining simulated references (sentences with distortion typical for a mobile system) and MNRU (Modulated Noise Reference Unit). Both male and female speakers are used. When the SQI algorithm is updated, we can make comparative listening tests towards the absolute reference scale. The test will have a small variance (The MNRU scale is measured in dBQ which corresponds to signal to noise ratio) The SQI range comes from using this method. Ranges for SQI are:

GSM EFR: -20 <-> 30
GSM FR: -20 <-> 21
GSM HR: -20 <-> 17