HLR


HLR Presentation

Home Location Register
(HLR)
What is HLR ?
The HLR is the primary database that stores subscriber information for users who are “home subscribers” to that specific location register.

The HLR stores the following subscriber information
Identification information including :
Mobile Identification Number (MIN),
Mobile Directory Number (MDN), and
Equipment Serial Number (ESN)
Subscribed features and privileges
Feature information including feature activation status and feature registration information
Current subscriber location and activity status
The Role of the HLR
The HLR interworks with the MSC/VLR, AC, SMSC and feature servers to support origination/termination, authentication, SMS, packet transmission, location data, and the services of the intelligent network.

How can we know where a mobile station is?
The HLR has the necessary information for initiating, terminating, or receiving a call.
The MSC contacts the HLR prior to setting up the call.
The MSC delivers the call immediately.
As subscribers roam beyond their home area, the HLR keeps track of their locations and status.

How can we know where a mobile station is?
Whenever the MS is activated (powered on),
the Mobile Identification Number (MIN) and the Equipment Serial Number (ESN) are transmitted to the closest cell site, which notifies the HLR of the subscriber’s current location.
The HLR stores this information so calls can be forwarded to subscribers and service features can be accessed while the subscriber is roaming. The MS continues to transmit its identification at regular intervals so the network always knows the locations of all active  subscribers.
The MSCs and the HLR work together to continually track the location of a subscriber. When a subscriber is roaming and activates the MS, a cell site receives the signal containing the Mobile Identification Number (MIN) and ESN. This information is received by an MSC which transmits it to the mobile network for appropriate routing to the HLR.
Every few minutes, the handset resends this signal. As the subscriber moves from one cell site to another, the receiving MSC transmits the location of the MS to the HLR database for handoff.

Authentication Center(AC)
What is AC ?
The Authentication center which is one of the elements in the ANSI-41 network ( AC) is related to the HLR.
The AC provides the HLR with different set of parameters to complete the authentication of a MS(mobile station).
The AC is utilized to protect against unauthorized access in the mobile communication by “authenticating” mobile stations (MS) upon registration, call origination, call termination, and flash requests.
The AC interworks with ans external system using the MAP protocol over the SIGTRAN signaling network.
Authentication and encryption functions are provided in order to prevent illegal use of services, and to authenticate subscribers before requested services are provided to them
The authentication function shares a secret key between MS and network, executes the same authentication algorithm for them. Then, based on the result, corresponding MS is allowed to access the network.
Definition of Authentication Data
A-Key(Authentication Key, 64 bit)
A secret,64bit pattern stored in the MS and HLR/AUC
Used to generate the SSD(Shared Secret Data).

SSD(Shared Secret Data, 128 bit)
A 128bit pattern stored in the MS and known by BSS
SSD is concatenation of two 64bit subsets;
SSD-A(64 bit) is used to support the authentication
procedure.
SSD-B(64 bit) serves as one of the input to the process
generating the encryption mask and private long code.
RAND(Random Challenge Memory)
RAND is used in conjunction with SSD-A and other
parameters,  as appropriate authenticate MS orig.,
term. and  registration.
Operation of Authentication
Authentication Function
Deriving the SSD from the A-key
Shared Secret Data Update
It is a procedure of updating shared secret data (SSD) of the authentication center and mobile station. This procedure may always be executed every time when the AC requires. Thus, this command should be transmitted over traffic channel or paging channel to MS.
Global Challenge
Registration
Origination
Termination
Unique Challenge
This procedure is for authentication center to ask direct authentication for a particular MS. This procedure can always be executed every time when the AC requires, the command should be able to be transmitted over paging or traffic channel. Once the unique challenge fails, MS does not allow access the network, or performs the shared secret data update procedure. Command should be transmitted to MS over a channel. Once the unique challenge fails, access is not allowed to the network, or shared secret data updating procedure is executed.
Call History Count Update
Once an originating call and a terminating call completed successfully the authentication procedure, the AC sends parameter modification message to MS to update the MS Count. In normal state, count update is made in the process of originating and terminating call, though, it may occur in other time points. Consequently the procedure should be able to be made by paging and traffics. If unclear location data is notified from HLR or VLR, call history count should be updated.
MS Registration Flow
1.     MS-A sends Registration message to the Serving MSC with MIN
2.    The Serving MSC receives the REGNOT and forwards to VLR.
The VLR forwards the REGNOT to HLR associated to the MS-A
3.    The HLR Registers MS information in Database and returns a REGNOT to VLR
VLR records the identity of the MSC and the locations area identity an forwards a REGNOT to the Serving MSC
4.    Tee Serving MSC sends Sector List information
The BSC finds out its sector id in the received sector list from MSC
If so, BSC sends HOMEZONE or MOBILE information
MS would display received information
MS Registration Flow : with Authentication
1.    MS-A sends Registration message to the Serving MSC with MIN
2.    The Serving MSC/VLR receives the message and sends AUTHREQ to HLR associated to MS-A
The HLR forwards AUTHREQ to AUC and receives result
3.    HLR forwards the authreq to the Serving MSC/VLR
4.    Following successful authentication of the MS-A the Serving MSC/VLR sends REGNOT to HLR
5.    If the MS was previosly registered in another system, the HLR sends REGCANC to the previously serving system
6.    The previously serving MSC/VLR returns REGCANC to HLR
7.    HLR Registers MS information in Database and sends the REGNOT to the serving MSC/VLR
Call Origination(M-M:Local MS): with Authentication
1.     MS-A dials MS-B with MDN
On a call origination attempt by the MS-A, the Origination MSC/VLR sends an AUTHREQ to the HLR associated with the MS-A
The HLR forwards the AUTHREQ to the AUC and receives authreq as a results
3.    The HLR forwards authreq to the Originating MSC/VLR
The Originating MSC receives the message and sends LOCREQ to HLR
The HLR determines that the call shall be routed to a local MS and returns this information to the originating MSC in the LOCREQ
MSC paging to MS-B

Call Origination(M-M:Roaming MS)
MS-A dials MS-C with MDN
The originating MSC receives the message and sends LOCREQ to HLR associated to the MS-C
The HLR sends a ROUTREQ to the Serving VLR, VLR forwards the ROUTREQ to the MSC.
The Serving MSC allocated a TLDN and returns this information to the Serving VLR in the ROUTREQ
VLR forwards the ROUTREQ to the HLR
The HLR determines that the call shall be routed to an another MSC and returns this information to the MSC in the LOCREQ
A voice path is then established between the Jakarta MSC and Bandung MSC paging to MS-B
The serving MSC paging MS-C

Call Origination (M-M : Local MS)
MS-A dials MS-B with MDN
The Originating MSC receives the message and sends LOCREQ to HLR
HLR determines that the call shall be routed to  a local MS and returns this information to the originating MSC int the LOCREQ
MSC paging to MS-B
Call Origination (M-M : Roaming MS)
MS-A dials MS-C with MDN
The Originating MSC receives the message and determines the MS is in Bandung HLR so Jakarta MSC sends a LOCREQ to the Bandung HLR (associated to MS-C)
The HLR determines that the MS-C is roaming in Jakarta MSC and that the call shall be routed to a local MS
The HLR returns this information to the originating MSC in the LOCREQ
MSC paging MS-C

Service Feature
Service Features
Supplementary Services Provided by HLR
Call Forwarding-Busy (Act = *73, DAct = *730)
Call Forwarding-Unconditional (Act = *71, DAct = *710)
Call Forwarding-No Answer (Act = *74, DAct = *740)
Call Forwarding-Default (Act = *72, DAct = *720)
Call Waiting (Act = *40, DAct = *400)
Call Holding
Short Message Service
Fax Mail Service
Conference Call
Call Transfer
Message Waiting Notification
Remote Feature Control
Calling Number Identification Presentation
Calling Number Identification Restriction
Voice Mail Service
Call Forwarding to VMS : Busy
MS-A dials MS-C with MDN
The Originating MSC receives the message and sends LOCREQ to HLR associated to HLR MS-B
The HLR sends a ROUTREQ to the Serving VLR
The VLR forwards the ROUTREQ to the MSC
IF MS-C is busy, the status is returned to the HLR in the ROUTREQ
The HLR determines from the service profile that VMS is active. It sends the LOCREQ to the originating MSC including the VMS_ID
The Originating MSC then establishes a call to VMS.

Call Forwarding to VMS : Unconditional
MS-A dials MS-B with MDN
The Originating MSC receives the message and sends LOCREQ to HLR associated to HLR MS-B
The HLR determines from MS’ service profile that VMU is active
The HLR sends a locreq to the originating MSC providing the VMS_ID
The Originating MSC then establishes a call to VMS.

SMS (Short Message Send)
MS sends shorts message
MSC sends SMDPP
SMSC returns smdpp
SMSC sends SMSREQ to the HLR to get SMS routing address
HLR responds with an smsreq toward the SMSC
SMSC sends SMDPP to MS-C
MSC sends smdpp to SMSC

Calling Number Identification Presentation (CNIP)
Calling Number Identification Restraction (CNIR)
MS-A dialing to MS-B
MSC receives the message and sends LOCREQ to HLR (including CNI information)
HLR sends locreq (including CNI information)
MSC paging to MS-B
IF MS-B has CNIP service, MS-B alerted including Calling Number Identification Presentation information
IF MS-A has CNIR service then CNI information will not displayed MS-B

Message Waiting Notification
Voicemail message is waiting to be delivered to the subscriber (MS-A). But the MS-A is not available for alerting
MSC receives an indication that the MS-A is available for alerting
MSC send a REGNOT to the HLR associated to the MS-A
HLR returns a regnot to the MSC/VLR
MSC then provides a MWN alert to the MS-A
What is new service?
FWA is a limited mobility service within pre-defined mobility area.
Subscriber’s mobility is limited within pre-defined Limited Mobility Service Area.
Limited Mobility Service Area (LMSA) is PSTN Local Service Area.

What is new service?
Subscriber can proceed (Originate & Terminate) a call only inside the pre-defined subscriber’s LMSA.

What is new service?
HLR send the LMSA code of Subscriber to MSC/VLR when MS‘s initial register, location update and changed profiles
What is new service?
MSC determines to permit or limit a call origination according to the result of comparing with subscriber’s present location area and LMSA
What is new service?
MSC determines to permit or limit a call termination according to the result of comparing with subscriber’s present location area and LMSA

Thank You

Sriyono.basuki@mobile-8.com

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