call setup success rate formula breakdown
TRANSCRIPT
� Background on CSSR formula◦ Identify components in Call Setup Success Rate formula
� Comparing with other CSSR formula from other vendor
� CSSR tracks the percentage of call attempts that result in successful TCH accesses, to be more specific, TCH for voice
� All other call attempts that do not require TCH for voice is excluded from the formula◦ Example: location area updates, send and receive SMS, Supplementary Service Access, etc.
_ _ _100%
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CALL SETUP SUCCESSFUL CALLS
SUCCESS RATE CALL ATTEMPTS= ×
� a sum of successful TCH seizures and redirected assignment occurred in cell
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TOTAL CALLS
SUCCESSFUL ASSIGNMENT REDIRECTION directed retry
CALLS ASSIGNMENT REDIRECTION during assignment
ASSIGNMENT REDIRECTION multiband band
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= +
+
� A sum of incoming and outgoing call attempts occurred in a cell
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CALL Mobile Ter ated Call Attempts
ATTEMPTS Mobile Originated Call Attempts
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1. Any mobile terminated call attempt transaction such as incoming call, SMS, location services pegged OK_ACC_PROC[page_response]
2. There are 3 types of mobile terminated call attempt transaction that don’t require TCH for voice, these are:
� Mobile terminated SMS
� Mobile terminated Location Services
� mobile terminated SMS performed on TCH signalling
3. The number of mobile terminated call attempt should not include transactions defined in point 2
� Where:◦ Mobile terminated SMS is defined as:
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OK ACC PROC page response
Mobile Terminated Mobile Ter ated SMS
Call Attempts Mobile Ter ated Location Services
MT SMS on TCH because FCS
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= −
−
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SMS INIT ON SDCCH
SMS INIT ON SDCCH HO IN
OK ACC PROC cm serv req sms
OK ACC PROC loc flw on req sms
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−
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oMobile Terminated Location Services:•MT_LCS_ON_SDCCH
o Mobile Terminated SMS on SDCCH due to FCS feature
SMS_INIT_ON_TCH_FCS
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OK ACC PROC page response
OK ACC PROC cm serv req sms
OK ACC PROC loc flw on req smsMobile Terminated
MT LCS ON SDCCHCall Attempts
SMS INIT ON SDCCH
SMS INIT ON SDCCH HO IN
SMS INIT ON TCH FCS
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+
= −
−
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−
� Mobile originated call attempt is a collection of the following transaction:◦ Normal calls
◦ Emergency calls
◦ Re-establishment calls
◦ Normal calls followed after location update
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OK ACC PROC cm serv req call
Mobile Originated OK ACC PROC cm serv req emerg
Call Attempts OK ACC PROC cm reestablish
OK ACC PROC loc flw on req norm
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= +
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OK ACC PROC page response
OK ACC PROC cm serv req sms
OK ACC PROC loc flw on req smsMobile Terminated
MT LCS ON SDCCHCall Attempts
SMS INIT ON SDCCH
SMS INIT ON SDCCH HO IN
SMS INIT ON TCH FCS
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+
= −
−
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−
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OK ACC PROC cm serv req call
Mobile Originated OK ACC PROC cm serv req emerg
Call Attempts OK ACC PROC cm reestablish
OK ACC PROC loc flw on req norm
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= +
+
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OK ACC PROC cm serv req call
OK ACC PROC cm serv req emerg
OK ACC PROC cm reestablish
OK ACC PROC loc flw on req norm
OK ACC PROC page responseCALL
OK ACC PROC cm serv req smsATTEMPTS
OK ACC P [ _ _ _ _ ]
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−
− + −
ROC loc flw on req sms
MT LCS ON SDCCH
SMS INIT ON SDCCH
SMS INIT ON SDCCH HO IN
SMS INIT ON TCH FCS
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OK ACC PROC cm serv req call
OK ACC PROC cm serv req emerg
OK ACC PROC cm reestablish
OK ACC PROC loc flw on req norm
OK ACC PROC page responseCALL
OK ACC PROC cm serv req smsATTEMPTS
OK ACC P [ _ _ _ _ ]
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_ _ _
_ _ _ _ _
_ _ _ _
−
− + −
ROC loc flw on req sms
MT LCS ON SDCCH
SMS INIT ON SDCCH
SMS INIT ON SDCCH HO IN
SMS INIT ON TCH FCS
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TOTAL CALLS
SUCCESSFUL ASSIGNMENT REDIRECTION directed retry
CALLS ASSIGNMENT REDIRECTION during assignment
ASSIGNMENT REDIRECTION multiband band
+
= +
+
_ _ _100%
_ _
CALL SETUP SUCCESSFUL CALLS
SUCCESS RATE CALL ATTEMPTS= ×
_
_ [ _ ]
_ [ _ ]
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_ _ [ _ _ _ ]_ _
TOTAL CALLS
ASSIGNMENT REDIRECTION directed retry
ASSIGNMENT REDIRECTION during assignment
CALL SETUP ASSIGNMENT REDIRECTION multiband band
OK ACC PROC cm serv req callSUCCESS RATE
O
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=
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K ACC PROC cm serv req emerg
OK ACC PROC cm reestablish
OK ACC PROC loc flw on req norm
OK ACC PROC page response
OK ACC PROC cm serv req sms
OK ACC PROC loc flw on req sms
MT LCS ON SDCCH
SMS I
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+
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−
−
100%
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NIT ON SDCCH
SMS INIT ON SDCCH HO IN
SMS INIT ON TCH FCS
×
+ −
� CSSR is defined as a percentage of successful access on SDCCH factorised by the percentage of successful BSS assignment
� CSSR = (Assignment_Success_Rate) * (1 -SDCCH_RF_Loss_Rate)) / 100
SDCCH RF LOSS = ¼ = 25%
Assignment Success Rate = 100%
CSSR = (Assignment_Success_Rate) * (1-
SDCCH_RF_Loss_Rate)) / 100%
CSSR = 100 * ( 75)/100% = 75%
SDCCH RF Loss = ¼ = 25%
Assignment Success Rate = 100%
CSSR = Successful Calls/ Call Attempts
*100%
CSSR = 3 / 3 * 100% = 100%
� Scenario:– 4 SDCCH Access attempts, 1 for location update and 3 for call setups
– Due to certain cause, 1 SDCCH access for location update has failed
– All 3 call setups successfully assigned to TCH
Other Vendor Motorola
More Accurate