User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
4 System Function
4-3
4.2 Call Procedure
Call procedure mainly includes speech service call procedure and data service call
procedure. This section gives some typical examples to introduce the MS call
procedures.
4.2.1 Speech Service Call Procedure
I. MS-origina ted call (MOC)
MS-originated call procedure is illustrated in Figure 4-4.
MS
BTS
BSC
Origination Msg
Abis-ACH Msg Transfer(ORM)
Abis-PCH Msg Transfer(Base Ack)
Base Ack Order
Abis-BTS Setup
Abis-Connect
Abis-Connect Ack
Abis-BTS Setup Ack
Abis-IS2000 FCH Fwd(Null data)
Null Traffic Data
Abis-IS2000 FCH Rvs(Idle data)
Abis-PCH Msg Transfer(ECAM)
ECAM
Traffic Channel Preamble
Abis-IS2000 FCH Rvs(Preamble)
Abis-IS2000 FCH Fwd(Base Ack)
Base Ack Order
Idle TCH Data
Abis-IS2000 FCH Rvs(Idle Data)
MS Ack Order
Abis-IS2000 FCH Rvs(Ms Ack)
Abis-IS2000 FCH Fwd(Service Connect)
Service Connect Msg
Service Connect Complete
Abis-IS2000 FCH Rvs(Ser Conn Comp)
CM Service Req
Assignment Complete
MSC
Assignment Req
ACH
PCH
TCH
PCH
TCH
TCH
TCH
TCH
TCH
TCH
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
Figure 4-4
MS-originated call procedure
1) MS sends "Origination Message" on access channel. On receiving the
message, BTS sends “Abis-ACH Msg Transfer” message to BSC.
2) BSC sends “CM Service Request” message to MSC, to request service
assignment. Meanwhile, BSC sends “Base Ack” order to BTS via “Abis-PCH
Msg Transfer” message. BTS sends “Base Ack Order” on paging channel to the
MS.