Wireless and Mobile Network Architectures
description
Transcript of Wireless and Mobile Network Architectures
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Wireless and Mobile Network Architectures
Wireless and Mobile Wireless and Mobile Network ArchitecturesNetwork Architectures
Chapter 7Chapter 7
PACS Network SignalingPACS Network Signaling
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PACS Network SignalingPACS Network Signaling
We describes network signaling for the Personal Access We describes network signaling for the Personal Access Communications System (PACS)Communications System (PACS)
PACS supports basic call control, roaming, and handoff PACS supports basic call control, roaming, and handoff managementmanagement
Does not use MSCs or HLR/VLR, but uses Advanced IntDoes not use MSCs or HLR/VLR, but uses Advanced Intelligent Network (AIN) protocol with an Access Manager elligent Network (AIN) protocol with an Access Manager (AM), AIN switch, and AIN SCP, SSP(AM), AIN switch, and AIN SCP, SSP
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Advanced Intelligent Network (AIN)Advanced Intelligent Network (AIN)
By taking full advantage of the network intelligence generBy taking full advantage of the network intelligence generated by SS7 advancements ated by SS7 advancements
the Advanced Intelligent Network (AIN) can deliver new anthe Advanced Intelligent Network (AIN) can deliver new and profitable services to subscribers. d profitable services to subscribers.
In the AIN environment, new services are not tied to the cIn the AIN environment, new services are not tied to the call-processing logic of individual switching systems, but aall-processing logic of individual switching systems, but are defined through the interworking of these switches and re defined through the interworking of these switches and other network elements. other network elements.
A switch is alerted to the need for AIN processing through A switch is alerted to the need for AIN processing through various types of triggers that can accompany a call. various types of triggers that can accompany a call.
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PACS ArchitecturePACS Architecture
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PACS Network InterfacesPACS Network Interfaces
The RPCU provides management and control functions between the RP and the local exchange network.
The access manager (AM) in the RPCU, it provides: radio control : managing the RPs, trunk provisioning, RP to RP li
nk transfers non-radio service control : call control (managing the B channel
s), switching, routing The RPCU has to deal with inter-RPCU handoff (similar to inter-BSC
handoff) and inter-RP handoff. Note: an AM is also located in the AIN SCP; the two interact with th
e ISDN/AIN Switch providing tunneling/de-tunneling (i.e., encapsulation) of the ISDN REGISTER messages over AIN.
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The major goal of PACS network signalingThe major goal of PACS network signaling
Utilize the existing AIN network entities, such as AIN SCUtilize the existing AIN network entities, such as AIN SCP and SSPP and SSP
there is no need to create new entities, such as MSC, uthere is no need to create new entities, such as MSC, using in other PCS systems.sing in other PCS systems.
In PACS signaling, telephony switching functions are sepIn PACS signaling, telephony switching functions are separated from the PCS-related signalingarated from the PCS-related signaling
To achieve this goalTo achieve this goal Noncall-associated signaling is introduced to minimize the modi
fications to the AIN SSP; that is, the AIN SSP does not interpret the PCS-related or IS-41-like signaling message
Many functions of the MSC have been removed from the SSP and moved to the AM and RPCU
The creation of the RPCU introduces a new kind of handoff : inter RPCU handoff
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AIN/ISDN SwitchAIN/ISDN Switch The AIN switch is equipped with SS7, ISDN, and AIN capabilities. SS7 ISUP is used in the switch to set up the trunks in call control
and intersystem handoff. The SS7 TCAP is used to support mobility management, and to tra
nsport AIN message between the switch and the SCP. Triggering and querying
Triggering is the process of identifying calls that need AIN handling Querying is the process of assembling an AIN message to an AIN SCP
at a trigger detection point ISDN/AIN Interworking
Noncall-associated (NCA) signaling provides a generic method for the SCP to communicate with an ISDN connected device through the switch
PACS Network ElementsPACS Network Elements
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PACS Network ElementsPACS Network Elements
AIN SCPAIN SCP The AIN SCP provides the service logic, database, and operation
capabilities to support HLR, VLR, AM and Auc. The SCP communicates with the switch using AIN TCAP and the
external PCS database using the IS-41 protocol. The HLR contains a PCS application process, end-user service p
rofiles, and accounting management capabilities.
Intelligent peripheralIntelligent peripheral 지능망 서비스에서 제공되는 각종 안내 멘트를 제공하고 ,
사용자와의 음성 인터페이스를 통해서 필요한 정보를 제공하며 , 서비스를 위해 필요한 각종 정보 ( 사용자 번호 , 비밀번호 , 서비스 선택 등 ) 를 수집하는 기능을 제공합니다 .
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PACS Network InterfacesPACS Network Interfaces
AIN interfaceAIN interface During the call-processing procedure, the switch may detect the ne
ed for AIN processing at trigger detection points (TDPs) Then process between the AIN switch and the AIN SCP
ISDN interfaceISDN interface The RPCU communicates with the switch via ISDN basic rate interf
aces (BRIs)
Terminal Service Profile 1 (DN1)
Terminal Service Profile 2 (DN2)
Virtual Terminal 1 (DN1)
Virtual Terminal 2 (DN2)
B Channel
B Channel
D Channel
Switch RPCU
ISDN Basic Rate Interface
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In ISDN signaling, every message contains a common In ISDN signaling, every message contains a common mandatory information element, referred to as the call mandatory information element, referred to as the call reference.reference.
ALERT ALERT B channel selection
CALL-PROC CALL-PROC call establishment from the called party to calling party
CONN , CON-ACK CONN , CON-ACK call acceptance by the called party
REL , REL-COMREL , REL-COM SETUPSETUP
Call initiation from calling party to called party FACILITYFACILITY
To request permission for a handoff operation (AIN switch RPCU)
REGISTERREGISTER To inform the VLR to carry out various operations
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AIN/ISDN InterworkingAIN/ISDN Interworking
With NCA signaling, the switch provides interworking functWith NCA signaling, the switch provides interworking functions between the SCP/VLR(AIN) and the RPCU (ISDN).ions between the SCP/VLR(AIN) and the RPCU (ISDN).
The ISDN messages exchanged between the switch and The ISDN messages exchanged between the switch and the RPCU are of type the RPCU are of type REGISTERREGISTER
The AIN messages exchanged between the switch and thThe AIN messages exchanged between the switch and the VLR are of type e VLR are of type NCA_DataNCA_Data
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NCA Signaling Initiated by the RPCUNCA Signaling Initiated by the RPCU The RPCU initiates NCA signaling by The RPCU initiates NCA signaling by
sending an ISDN REGISTER message to the sending an ISDN REGISTER message to the switch.switch.
The switch forwards the information to the The switch forwards the information to the VLR using an AIN NCA_DATA messageVLR using an AIN NCA_DATA message..
VLR Switch RPCU
REGISTER
REL-COM
NCA_Data
Invoke Component of FacilityMSG Type
envelopNCADataREGISTER
MSG Type
NCA_Data
Package Type
Unidirectional
Component Type
Invoke(Last)
Component
nCAData
(ISDN message)
(AIN message)
<NCA message format translation (ISDN to AIN)><NCA signaling initiated by the RPCU>
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NCA Signaling Initiated by the VLRNCA Signaling Initiated by the VLR
The VLR initiates NCA signaling by sending The VLR initiates NCA signaling by sending an AIN NCA_DATA message to switch.an AIN NCA_DATA message to switch.
The switch sends an ISDN REGISTER The switch sends an ISDN REGISTER message to the RPCU.message to the RPCU.
VLR RPCUSwitch
REGISTER
REL-COM
NCA_Data
Invoke Component of FacilityMSG Type
envelopNCAData5REGISTER
MSG Type
NCA_Data
Package Type
Unidirectional
Component Type
Invoke(Last)
Component
nCAData
(ISDN message)
(AIN message)
<NCA signaling initiated by the VLR> <NCA message format translation (AIN to ISDN)>
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NCA Signaling Initiated by the VLRNCA Signaling Initiated by the VLR
The REL-COM message is to clear the invocation The REL-COM message is to clear the invocation and the call reference of the REGISTER message.and the call reference of the REGISTER message.
The major goal of NCA signaling is to disassociate The major goal of NCA signaling is to disassociate the AIN SSP from PCS-related signaling.the AIN SSP from PCS-related signaling.
When the PCS signaling message is modified in When the PCS signaling message is modified in the feature, there will be no need to change the the feature, there will be no need to change the switch.switch.
NCA Signaling design featureNCA Signaling design feature The AIN SSP only translates the NCA signaling from one format
to another, the SSP does not interpret the message. In the ISDN interface between the AIN SSP and the RPCU, the
call reference is cancelled after every ISDN NCA message In the AIN interface between the AIN SSP and the AIN SCP, the
unidirectional TCAP message format is used instead of the general AIN transaction format- the query/response TCAP format
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RegistrationRegistration
1. REGISTER(P-REGNOT)
OldVLR/AM
HLRNew
VLR/AMISDN/AIN
SwitchRPCU
2. NCA_Data(P-REGNOT)
8. NCA_Data(P-REGNOT-ACK)
9. REGISTER(P-REGNOT-ACK)
3. REL-COM
10. REL-COM
4. RegistrationNotification(INVOKE)
6. RegistrationCancellation(INVOKE) 5. RegistrationNotification
(RETURN RESULT)
7. RegistrationCancellation(RETURN RESULT)
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Call OriginationCall Origination
1. REGISTER(P-CALL-ORG)
TerminatingSwitch
VLR/AMServing
ISDN/AIN SwitchRPCU
2. NCA_Data(P-CALL-ORG)
3. REL-COM
Rining
4. NCA_Data(P-CALL-ORG-ACK) 5. REGISTER
(P-CALL-ORG-ACK)
6. REL-COM
7. SETUP
8. Info_Collected
9. Analyzed_Route
10. IAM
11. ACM
13. CALL-PROC
14. ALERT
12. ANM
15. CONN
16. CONN-ACK
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Call TerminationCall Termination
4. REGISTER(P-ALERT)
OriginatingSwitch
VLR/AMServing
ISDN/AIN SwitchRPCU
3. NCA_Data(P-ALERT)
5. REL-COM
Rining
1. Info_Analyzed
20. CONN
22. CONN-ACK
Serving SCPHLR
2. RouteRequest
6. REGISTER(ALERT_ACK)7. NCA_Data
(ALERT_ACK)8. REL-COM
9. RouteRequestAcknowledge
10. Analyze_Route
11. NCA_Data(RCID_ASSIGN) 12. REGISTER
(RCID_ASSIGN)
13. REL-COM
14. IAM
15. Termination_Attempt
16. Forward_Call
17. SETUP
18. ALERT
19. ACM
21. ANM
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NewRPCU
OldRPCU
Old Switch
New Switch
NewRPCU
OldRPCU
Old Switch
New Switch
Before the ALT After the ALT
Intersystem HandoffIntersystem Handoff
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Intersystem HandoffIntersystem HandoffOld
RPCU VLR/AM New SwitchNew
RPCU
The portable moves from old RPCU to the new RPCU
Old Switch
1. SETUP(ALT REQUEST)
3. IAM
2.CALL-PROC4. FACILITY
(ALT REQUEST)
5. FACILITY(ALT PERMISSION)
6. ANM
7. CONN
8. CONN-ACK
9. REGISTER(ALT COMPLETE)10. NCA_Data
(ALT COMPLETE)11. REL-COM
12. NCA_Data(ALT COMPLETE)13. REGISTER
(ALT COMPLETE)
14. REL-COM
15. DISC
16, REL
17. REL-COM
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Inter-RPCU hand-off approachesInter-RPCU hand-off approaches
OldRPCU
NewRPCU
RP RP
Switch
OldRPCU
NewRPCU
RP RP
Switch
OldRPCU
NewRPCU
RP RP
Switch
OldRPCU
NewRPCU
RP RP
Switch
OldRPCU
NewRPCU
RP RP
Switch
(a) Before ALT (b) After ALT(Switch Loopback)
(c) After ALT(Direct Connect)
(d) During ALT(Three-way Calling Connection)
(e) After ALT(Three-way Calling Connection)
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Inter-RPCU hand-off approachesInter-RPCU hand-off approaches
To minimize the impact of inter-RPCU handoff on the AIN SSP, tow anchorTo minimize the impact of inter-RPCU handoff on the AIN SSP, tow anchor-RPCU handoff approaches have been proposed.-RPCU handoff approaches have been proposed.
In the switch loopback,In the switch loopback, The old RPCU dials the new RPCU to make the connection through the switch. disadvantage : handoff consumes two more links between the switch and the
RPCUs In the Direct connection,In the Direct connection,
The RPCUs are connected with trunks Disadvantage : extra trunks are required to connect the RPCUs
and an inter-RPCUs handoff protocol is required Three-way calling connectionThree-way calling connection
Utilize the existing three-way calling facility of the AIN switch Minor modifications to the RPCU , does not consume extra trunks