SMS affects regular voice channel !!

[justdream]

Dears,

Do you know how to analyze if SMS affects regular voice channel through tier 3?

Sorry if my quetsion is not very clear as I've just been asked about
I don't even know what's meant by Tier 3?

[harrypotter]

SMS uses different timeslot and Voice uses different timeslot as well, SMS is considered as data and doesnt really affects the Voice traffic. If you have SMS congestion you should add more timeslot to accomdate your increasing SMS traffic.

[justdream]

I guess tier 3 means layer 3 messages, may be it was wrong translation from my friend :-)

[abdelrahman.mansour]

SMSs uses SDCCH channels which is assigned uniqe TCHs if you are speaking about 2G , and its sent on Fach in 3G

in conclusion : No affect

[justdream]

Dears, please guide ASAP how to ckeck from layer 3 messages, if I got for example rejected call due no channel avaialable "as in same tiem of Test SMS test was also running"

also how to check for layer 3,, SDCCH saturation, congested, blocked, etc

Your fast response will be highly appreciated (using actix if possible)

[plannerguy]

Hi


TeMS

in event click on blocked call

same will highlight the reason on layer3

in layer3 you can see the specifc reason

or in window mode reports MPH


Regards
Plannerguy

[m121]

Just to specify a little bit SMS delivery:
MS in dedicated mode uses SACCH in 2G associated to TCH it uses.
Otherwise it uses SDCCH.
SACCH doesn't interrupt voice but is used for MR so no MR for that period so power control is corrupted and it could affect a voice quality but only slightly and chances are veeeery slim that it will happen.
Regarding blocking - SMS should not affect call blocking because SDCCH have associated FACH and Paging is performed trough it. So no missed call while sending SMS!

[zeezzoo]

I agree with most what m121 said but i have a little thing to correct . let's take a look first at SMS signaling while MS in connected mode :

term sms connected mode.jpg
Terminated SMS - MS in connected mode

org sms connected mode.jpg
Originated SMS - MS in connected mode

for terminated SMS : all what m121 said is absolutely right .

for originated SMS : you can see that the MS uses the "FACH" to send the request and receive the response that tell it "you can send the SMS on the SACH now"

FACH works in stealing mode == steal TCH & use it as a fach == instead of sending the voice on the tch , the MS will send some signaling messages ==> voice quality will degrade .

FACH is also used in HO .
The message flow is from Siemens BR9.0
the images are also attached in the rar file
no password

hope it will be useful
BR,

[jimjim]

Dears, please guide ASAP how to ckeck from layer 3 messages, if I got for example rejected call due no channel avaialable "as in same tiem of Test SMS test was also running"

also how to check for layer 3,, SDCCH saturation, congested, blocked, etc

Your fast response will be highly appreciated (using actix if possible)

Dear Justdream,

Why not have a look into statistics. In ******** for instance there are counters TCH Blocking rate and SDCCH Blocking rate.

Additionally there is a complete set of KPIs to judge whether that you have a problem in SDCCH or TCH.


Regards,

[ritgail]

TCH means for Traffic voice/data...it is fixed. See ETSI specification if required.
No SMS is going through TCH.

For SMS,
orgination:
MS RACH------->BTS
BTS--------->AGCH MS with SDCCH details
MS---------tunes to defined SDCCH....sends sms
MSC------------>release SDCCH form MS.

Termination:
MS will listen to PCH----then if it is paged then the process is same as above.

If the MS in dedicated mode, means if it is holding a TCH, then sms will go in SACCH....that is the only deviation.

For, making of termination call.. the MS will go through the same steps as above...

MS RACH------->BTS
BTS--------->AGCH MS with SDCCH details
MS---------tunes to defined SDCCH....sends sms
MSC------------>release SDCCH form MS.(With TCH details)
MS----tunes to TCH....


So, for both SMS/Call we require SDCCH....which is configured like combined BCCH/ total 4 channel available(say for 2/2/2 config site).....or standalone
then 8 SDCCH with combined BCCH total-12

So these SDCCH are also delicately require by ms for above services.....

if there is high SMS shooting at BBH, this may reduce SD for TCH...then your situation may come into picture...

Look for SD congestion....