Home » Topics » Telecom Design » RLT & ARLT
M Guest
Hi All,
Can anybody tell me y we generally give ARLT higher value than that of RLT ?
Lets Say:
RLT :20 SACCH Frames.
ARLT :28 SACCH Frames.
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Bijoy Guest
because AMR codecs are more prone to signalling Drops.
Br\\
Bijoy
M Guest
Thnx Bijoy,
Can u explain a bit more about this.
//
Bijoy Guest
Let me try.
With AMR we are increasing speech robustness,but not of the SACCH.So,though the subscriber may not experience degraded speech quality,call drop may take place due to RLT timeout,so we increase the RLT value for AMR.
Pix Guest
The AMR RLT is just a workaround, very ugly one…
The proper solution proposed by 3GPP is actually to implement Repeated SACCH, to increase SACCH Robustness, in case of AMR call.
Pix
Bijoy Guest
Thats correct.
Repeated SACCH & FACCH feature though came quite late as a remedy
Br\\
Bijoy
Pix Guest
Yes, something like 5 years after AMR implementation :))
you would think that GSM 3gpp people are mainly working on improving speech quality. Because that is what GSM does best : voice…
But no, they spend time improving the packet domain (DTM, EDA, NC2 Reselections, superb codecs and retransmissions, etc)….
Strange…
JOE Guest
Hi,
I have question about repeated Facch, Sacch in ALU:
Why after activation of repeated SACCH/FACCH the call drop increase mainly with reason DL Quality??? Pls help!
pix Guest
hi joe,
what do you mean “call drop with bad quality” ? which indicator do you refer too ?
the “RTCH Drop rate due to radio” increased, is that it?
Please detail your issue, I’ll do my best to help.
Regards,
pix
Nitin Giri Guest
what is use arlt & ahrlt and what is impact after value increament
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