CS and PS KPI 2414.pptx

8/10/2019 CS and PS KPI 2414.pptx

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CS & PS KPI Training-Location update-Paging success rate-Attached success rate-PDP success rate

SMS success rate

MMS Success rate


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GSM Network Structure


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Meaning of Network Element

MS _ Carried by subscriber it consist of ME (Mobile Equipment) SIM (Subscriber identity module) it contain the customer related

information ( identification, secret key for authentication)

BSS _ control radio links with mobile station it consist of BTS (base trans receiver station) it define a cell and is responsible toestablish the radio link with MS

BSC( Base station controller )it controls multiple BTSs and manage radiochannel set up and handovers .BSC is the connection between BTS andMSC

MS, BSS and NSS


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NSS _ Network and switching subsystem (NSS)

mobility management and switching of calls between mobile use and fixed network it consist ofMSC is the central component of NSS. Operate all switching function for mobile, Many BSC can belong to one MSC. Manages the location of mobile. Switches call

. Manages security features

. Control hand overs between BSCs

. Collect call billing data and send to billing center

. Collect traffic statistic for performance monitoringHLR _ contains all subscriber information for the purposes of call control and location determinationit is a central master database containing user data, permanentVLR _it is a temporarily storage , including data about all user currently in the domain of the VLRAUC _ is a protection database that stores the security information for each subscriber ( a copy ofthe secret key is stored in the SIM) which is used for authentication and encryption over the radiochannelEIR _is a database that contains a list of all valid mobile Equipment on the network where eachmobile is identified by its international mobile equipment IMEI . An IMEI is marked as invalid if it hasbeen reported storen or not type approved

NSS network element

NSS


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Location update is the procedure that allows a mobile device to inform the network when it moves from onelocation to the next , when switching on or off the phone and register for the fist time

Types of location update

IMSI attached / detached

Normal Location update Periodic Location update

Normal location updating MS has to do a location update in new location area when it crosses a LAC border.

IMSI attach location updating procedure When mobile switch ON it has to do a location update

When moving from non coverage area to a coverage area MS has to do a location update if LAC isdifferent from stored LAC When mobile switch OFF it has to detached from the network

Periodic location updatingThe network has to do a periodic location updates to update the subscribers in each location area.

Location update (LU)


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Challenges

Poor signal No network coverage MS status

Paging:

For what the paging is used?

Used to alert the mobile station of an incoming call. Paging is a procedure the network uses to find out a subscriber's location before actual call

establishment. Paging is a separate procedure used in the case of a Mobile Terminated Call for Mobile Subscriber

searching. Paging is initiated by the NSS and is based on the Location Registration information theMobile Subscriber has supplied when performing the Location Update.

Challenges Phone switched off Out of network Lack of resources PCH Link issues

Paging


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when the LU requests is received by the new VLR authentication is performed

If authentication is successful the VLR check its database to determine whether it has a record for the MSsubscriptionWhen VLR find no record for MS it send a request to the subscribes HLR for a copy of the MS subscriptionThe hlr passes the information to the VLR and updates its locaton infotmation for the subs. The HLRinstructs the old VLR to delete the information it has about the ms subsripton

Location u[date process


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Call Process

Mobile Originating Call MOC

1. Channel Request: The MS requests for the allocation of a dedicated signaling channel to perform the call setup.

2. After allocation of a signaling channel the request for MOC call setup, included the TMSI (IMSI) and the last LAI,is forwarded to the VLR

3. The VLR requests the AC via HLR for Triples (if necessary).

4. The VLR initiates Authentication, Cipher start, IMEI check (optional) and TMSI Re-allocation (optional).

5. If all this procedures have been successful, MS sends the Setup information (number of requested subscriber anddetailed service description) to the MSC.

6. The MSC requests the VLR to check from the subscriber data whether the requested service an number can behandled (or if there are restrictions which do not allow further proceeding of the call setup)

7. If the VLR indicates that the call should be proceeded, the MSC commands the BSC to assign a Traffic Channel (i.e.resources for speech data transmission) to the MS

8. The BSC assigns a Traffic Channel TCH to the MS

9. The MSC sets up the connection to requested number (called party).

Remark: This MOC as well as the MTC described in the following describes only the principles of an MOC / MTC,not the detailed signaling flow.


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Call Setup Success Rate KPI


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Mobile terminated call

Mobile termited call MT

Paging the Mobile Station The MSC/VLR then orders all of its BSCs and BTSs to page the MS. Sincethe MSC/VLR does not know exactly which BSC and BTS the MS ismonitoring, the page will be sent out across the entire Location Area.

Initial Setup The MS receives the Page Request (PAG_REQ) on the PCH. The MS

recognizes that the page is intended for it, based on a TMSI or an IMSI. The MS sends a Channel Request (CHAN_REQ) message on the RACH. Call Establishment Once the user answers the call (by pressing the send button), the MS will

send a Connect CON message to the MSC. The Connect message isforwarded back to the caller's switch to activate the call.

The MSC sends a Connect Acknowledge CON_ACK message to the MS andthe call is established.


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GPRS


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The main new network architecture entities that are needed are: SGSN: GPRS Support Node - this forms a gateway to the services within the network. GGSN: Gateway GPRS Support Node which forms the gateway to the outside world. PCU: Packet Control Unit which differentiates whether data is to be routed to the packet switched or

circuit switched networks. VGS_ Valua Groth Service

SGSN

The SGSN or Serving GPRS Support Node element of the GPRS network provides a number of takesfocused on the IP elements of the overall system. It provides a variety of services to the mobiles:

Packet routing and transfer Mobility management Attach/detach Logical link management Authentication Charging data There is a location register within the SGSN and this stores location information (e.g., current cell, current

VLR). It also stores the user profiles (e.g., IMSI, packet addresses used) for all the GPRS users registeredwith the particular SGSN.

GPRS


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GGSN

The GGSN, Gateway GPRS Support Node is one of the most important entities within theGPRS network architecture.

The GGSN organizes the interworking between the GPRS network and external packetswitched networks to which the mobiles may be connected. These may include both Internet

The GGSN can be considered to be a combination of a gateway, router and firewall as it hides

the internal network to the outside. In operation, when the GGSN receives data addressed toa specific user, it checks if the user is active, then forwarding the data. In the oppositedirection, packet data from the mobile is routed to the right destination network by theGGSN.

PCU The PCU or Packet Control Unit is a hardware router that is added to the BSC. It differentiates

data destined for the standard GSM network (circuit switched data) and data destined for theGPRS network (Packet Switched Data). The PCU itself may be a separate physical entity, ormore often these days it is incorporated into the base station controller, BSC, thereby savingadditional hardware costs.

GPRS


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In order for the GPRS MS to receive or transmit data the end user needs to perform a two-step procedure,GPRS attach and PDP context activation

GPRS attach mean?

GPRS attach means that the mobile phone is registered to a GPRS network. GPRS attach is also allowing

mobility i.e. the network is keeping track of the mobile movements. In addition, the mobile isauthenticated and ciphering is enabled At GPRS attach a logical link is established between MS and SGSN, the GPRS attachment procedure When a MS is turned on, the first function it performs is a GPRS attach

GSM access authentication (towards Home Network, HLR (Authentication Center)) User profile is downloaded from HLR to the serving SGSN

When the GPRS attach is complete, the MS is physically connected to the visited network

GPRS ATTACHED


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Packet Data Protocal (PDP) context activation

Packet Data Protocol (PDP) Context Activation

After the GPRS Attach procedure is over, the terminal is pre-prepared for the datacommunication.

So when terminal wants to start the communication it must establish a Packet Data

Protocol Context (PDP context).


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GPRS PDP Context flow


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GPRS

Packet Data Protocol (PDP) Context Activation

The MS sends an Activate PDP Context Request (PDP Type, PDP Address, AccessPoint Name, QoS Requested, PDP Configuration Options) to the SGSN, to indicatewhether the MS will use a static or a dynamic PDP addresses. The SGSN checks theuser subscription.

The SGSN sends a Create_PDP_Context_Request message to GGSN.

The activationcreates a tunnel/logical link between a PDP context in the SGSN and a PDP context inthe GGSN. The GGSN obtains the IP address from the external data network, and isforwarded to the MS. If the GGSN replies to the SGSN with a positiveCreate_PDP_Context_Response message, the SGSN activates the PDP context and isready to forward packets between the MS and the GGSN.

The GGSN returns an Activate PDP Context Accept to the MS. After the PDP contextactivation, a connection between the MS and the external data network isestablished. The SGSN is ready to route and charge for packets delivered (GGSNMS).


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Um between an MS and the GPRS fixed network part. The Um is the access interface the MS uses toaccess the GPRS network. The radio interface to the BTS is the same interface used by the existing GSMnetwork with some GPRS specific changes.

Gb between a SGSN and a BSS. The Gb interface carries the GPRS traffic and signalling between the GSM

radio network (BSS) and the GPRS network. Frame Relay based network services is used for this interface Gr between an SGSN and the HLR. The Gr gives the SGSN access to subscriber information in the HLR. The

HLR can be located in a different PLMN than the SGSN (MAP). Ga between the GSNs and the CG inside the same PLMN. The Ga provides a data and signalling interface.

This interface is used for sending the charging data records generated by GSNs to the CG. The protocolused is GTP', an enhanced version of GTP.

Gs between a SGSN and a MSC. The SGSN can send location data to the MSC or receive paging requestsfrom the MSC via this optional interface. The Gs interface will greatly improve the effectiveness of theradio and network resources in the combined GSM/GPRS network. This interface uses BSSAP+ protocol.

Gd between the SMS-GMSC and an SGSN, and between SMS-IWMSC and an SGSN. The Gd interface isavailable for more efficient use of the SMS services (MAP).

Gf between an SGSN and the EIR. The Gf gives the SGSN access to GPRS user equipment information. TheEIR maintains three different lists of mobile equipment: black list for stolen mobiles, grey list for mobilesunder observation and white list for other mobiles (MAP).

Gc between the GGSN and the HLR. The GGSN may request the location of an MS via this optional

interface. The interface can be used if the GGSN needs to forward packets to an MS that is not active. Gi between a GGSN and an external network. The GPRS network is connected to an external data

networks via this interface. system will support a variety of data networks. Because of that, the Gi is not a standard interface, but

merely a reference point.

GPRS Interfaces and meaning


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SMS SMS Originating Part MO SM Submit : The SM is sent from the originating Mobile Station (MS) to the serving Mobile Switching

Center (MSC). The address of the SMSC where the SM should be submitted to is stored onthe SIM card of the subscriber and forwarded to the MSC with the message.

The MSC forwards the SM to the SMSC. The SMSC returns a positive (ACK) or negative (NACK)response indicating whether the message was successfully stored of not.

SMS Terminating Part MT SM Deliver : To delivers a SM SMSC has to find out the location (serving MSC) and the International

Mobile Subscriber Identity (IMSI) of the recipient subscriber first. This information (routinginformation) is retrieved from the Home Location Register (HLR) of the recipient subscriberbased on the recipient number (MSISDN).

HLR Provides routing Information to SMSC, which includes IMSI and serving MSC of recipientnumber.

Based on routing information SMSC delivers SM to the serving MSC and MSC forwards it tothe recipient Mobile Station.

VAS


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SMS Delivery Report : Successful Delivery On successful delivery SMSC sends delivery

report to the originator if requested. Failed Delivery If SMS is not delivered to the recipient number

SMSC send failure reason to the originator. Permanent Error : For example Unknown Subscriber Temporary Error : For example Absent Subscriber SMSC Retry : In case of temporary errors the SMSC schedules a

next delivery attempt, called SMSC retry. Network Trigger : If the subscriber is not reachable (absent) the

SMSC notifies the HLR that there is a message waiting for therecipient number. When the HLR detects the presence of thesubscriber, it alerts the SMSC and SMSC forwards SM to the servingMSC.

VAS


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OTA(OVER THE AIR): It is used to send settings e.g internet Change sms centre number Change service name e.g (TNM)

Ring Back Tone (RBT) Call flowMS_ MSC__HLR CRBT system

USSD

We have two USSD gateway Huawei

Cornastone

Multimedia Messaging Service (MMS ) is a standard way to send messages that include multimedia content to and from mobile phones .

VAS
http://en.wikipedia.org/wiki/Multimediahttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Multimedia

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CS and PS KPI 2414.pptx