30-06-2012, 05:34 PM
CELLULAR SYSTEM COMPONENT & ADDRESSING
CELLULAR SYSTEM COMPONENT.pptx (Size: 173.6 KB / Downloads: 33)
Switching system components or BSS :-
- Signaling Point (SP) addresses
- logical name
Logical names assigned by System Operator
Physical areas have identification names & numbers
- provide mobility management
- define billing areas
CELL GLOBAL IDENTITY
Used for unique identification
of cell & formed by adding 16 bits
to end of LAI
-allows possibility of 65,536 cell sites
RADIO BASE STATION IDENTITY CODE
Used by mobile operator
- To identify RBS within wireless network
Allows MS to distinguish between neighboring BSs
Consists of 3-bit network color code & BS color code
LOCATION NUMBERING
ID numbers assigned by service provider
Provide subscriber features
ADDRESSING CELLULAR NETWORK SWITCHING NODES
Messages between PSTN & PLMN sent to SS7 network
- To facilitate this operation :
SP addresses or Point codes assigned to network
switching element & processing node
MTP provides common platform for routing signal
ANSI based SS7 network numbering for SPs consist :
- 3 byte address that specify
telecom service provider (N= 0 - 255)
network cluster number(C= 0 - 255) &
member number (M=0 - 255)
In following format :
Signaling Point Code (SPC)=N-C-M
C denotes network geographic areas or section
M denotes identification of specific node
SP perform MSC/VLR or MSC/VLR/HLR
SS7 use one address for node & another subsystem address (SSN) – indicate individual element within node- SSN=6 for HLR
SSN=7 for VLR
SSN= 10 for AUC
GLOBAL TITLE & TRANSLATION
Address of a fixed network element
Address of network nodes –MSCs, HLRs, VLRs, AUCs & EIRS
Process incoming call to Gateway MSC
- location of MS
- uses MSISDN (MSISDN=CC+NPA/NDC+SN) number to point out appropriate HLR
- CC,NPA or NDC used from MSISDN to create GT to identify HLR
CALL ESTABLISHMENT
Mobile Originated Call
1: MS call - request signaling channel using common
control channel
2: Using SC,MS indicates – need service
- VLR sets status –”busy”
3: Authentication & encryption performed
4: Mobile specifies-type of service(voice call)
& number of party to be called
MSC/VLR acknowledge
5: Link set up b/w MSC & BSC & traffic
channel is seized