CALL FLOW OF MAIN 2G KPI
1. PSR (Paging Success Rate):
- Definition: Paging success rate, counted at MSC.
- Call Flow:
-
General formula:
PSR = 100% * Paging Success/Paging Attempt
Within:
o Paging Attempt is counted at A point in above call flow, when MSC send
paging message to BSC.
o Paging Success is counted at B point in above call flow, after MSC
receive Paging Respond message.
2. RASR (Random Access Success Rate):
- Definition: RASR is random access success rate, request to provide channel
successfully.
- Call Flow:
-
General formula:
RASR = 100% * RACH Success/RACH Attempt
Within:
o RACH Attempt is counted A point in above call flow, when BSC is
received requests of channel provision.
o RACH Success is counted based on number of RACH messages which
are decoded successfully.
3. SASR (SDCCH Assignment Success Rate)
- Definition: SASR is SDCCH channel Assignment Success Rate.
- Call Flow:
- General formula:
SASR = 100% * SDCCH Assignment Success/SDCCH Assignment Attempt
Within:
o SDCCH Assignment Attempt is counted at A point, when BSC receives
requests of channel provision from BTS.
o SDCCH Assignment Success is counted at B point, after BSC is received
successful assignment channel message (EST IND).
4. SCR (SDCCH Congestion Rate)
- Definition: SCR is SDCCH channel Congestion Rate.
- Call flow:
- General formula:
SCR = 100% * SDCCH Assignment Congestion/SDCCH Assignment Attempt
Within:
o SDCCH Assignment Attempt is counted at A point, when BSC receives
request of channel provision from BTS.
o SDCCH Assignment Congestion is also counted at A point, after BSC
checks available resource, if there is no enough resource congestion
counter will be counted.
5. SDR (SDCCH Drop Rate)
- Definition: SDR is SDCCH channel drop rate.
- Call flow:
-
General formula:
SDR = 100% * SDCCH Drop/SDCCH Assignment Success
Within:
o SDCCH Assignment Success is counted at A point, when BSC receives
successful channel assignment message (EST IND).
o SDCCH Drop is counted from A point to B point.
6. TASR (TCH Assignment Success Rate)
- Definition: TASR is TCH channel assignment success rate.
- Call flow:
-
General formula:
TASR = 100% * TCH Assignment Success/TCH Assignment Attempt
Within:
o TCH Assignment Attempt is counted at A point, when BSC receives
request of TCH channel assignment from MSC (ASS REQ).
o TCH Assignment Success is counted at B point, after BSC receives
successful TCH channel assignment message (ASS CMP).
7. TCR (TCH Congestion Rate)
- Definition: TCR is TCH channel congestion rate.
- Call flow:
-
General formula:
TCR = 100% * TCH Assignment Congestion/TCH Assignment Attempt
Within:
o TCH Assignment Attempt is counted at A point, when BSC receives
TCH channel assignment message from MSC (ASS REQ).
o TCH Assignment Congestion is also counted at B point, after BSC checks
available resource. If there is no enough resource, congestion counter will
be counted.
8. CSSR (Call Setup Success Rate)
- Definition: CSSR is call setup success rate.
- Call flow:
-
General formula:
CSSR = 100% * (1-SDR_exclude LU) * TASR
Where:
o CSSR is counted from A point to B point, from point successful SDCCH
channel assignment to the point successful TCH channel assignment.
o SDR is SDCCH channel drop rate excluding number of related
drop/attempt related of location update.
o TASR is TCH channel assign success rate.
9. CDR (Call Drop Rate)
- Definition: CDR is call drop rate.
- Call flow:
MS
BTS
BSC
MSC
Channel Req (1)
Channel Req (2)
Channel Act (3)
Channel Act Ack (4)
IMM ASS CMD (5)
SABM (6)
UA (7)
EST IND
(CM Service Req) (8)
CR (CMP L3 information) (9)
CC (10)
CM Service Accepted (11)
Setup (12)
Call proceeding (13)
ASS REQ (14)
Channel Act (15)
Channel Act Ack (16)
ASS CMD (17)
SABM (18)
UA (19)
EST IND (20)
ASS CMP (21)
ASS CMP (22)
Alerting (23)
Connect (24)
Disconnect (25)
Release Request (26)
Release complete (27)
-
A
B
General formula:
CDR = 100% * TCH Drop/TCH Assignment Success
Within:
o TCH Assignment Success is counted at A point, when BSC receives
successful TCH channel assignment message (ASS CMP).
o TCH Drop is counted from A point to B point.
10. HOSR (Outgoing Handover Success Rate)
- Definition:
- Call flow:
 Handover inter cell intra BSC:
 Handover inter cell inter BSC:
-
General formula:
HOSR = 100% * Handover Success/Handover Attempt
Within:
o Handover Attempt is counted at B1 point (flow intra BSC) or B3 point
(flow inter BSC), when BSC sends Hanover command.
o Handover Success is counted at C1 point (flow intra BSC) or C3 point
(flow inter BSC), after BSC receives Handover Complete message.