Network switching subsystem#Mobile switching center .28MSC.29

A Mobile -services Switching Centre ( MSC; German: switch to mobile networks) denotes a component of a GSM, UMTS or LTE mobile network.

The MSC is a fully digital exchange in the mobile network. It provides the interface between the radio network (base station subsystem BSS ) and the fixed telephone network dar. It is thus the central network element in the network switching subsystem ( NSS).

Each MSC is a certain proportion of the mobile network with all the Base Station Controller (BSC ) and subordinate base transceiver stations (BTS ) permanently assigned to that manage and control the radio traffic.

For all compounds that come from this part of the network or go there, the MSC performs the complete call management, local monitoring as well as authorization check (authentication ) of the mobile station. In addition, call data for each call for billing ( charging ) are recorded.

Also includes an MSC interface to other MSCs of the cellular network as well as to other components of the cellular network as Home Location Register (HLR), Signaling Transfer Points (STP), Service Control Point (SCP), short message service center (SMSC), and voice mail switching Center ( VMSC ) ( mailbox) that do interact with the MSC tasks or implement their specific requirements and data.

MSCs possess a " gateway MSC " (GMSC ) in addition or exclusively (without BSS) interfaces to other telephone networks. This can be to other mobile networks or connections in the fixed telephone network interfaces. Thus may be simultaneously GMSC basically any MSC.

Each MSC has a so-called visitor location register ( VLR) in which the data and the location of the subscriber are stored, currently within the control of the MSC. Where a participant with his mobile device in the influence area of ​​an MSC, its location in the central subscriber database, the Home Location Register is (HLR ) reported, on the one hand. On the other hand, all the subscriber data from the HLR to be loaded into the VLR the MSC.

Mediation scenarios

Mobile Terminated Call ( MTC)

If a mobile subscriber is called, is first determined by the assigned HLR in which MSC catchment area the user is located and turned the conversation to the appropriate MSC. The MSC is now located, in which location area the subscriber is located and built with the help of the associated radio network elements BSC and BTS the call to the subscriber on.

Mobile Originated Call ( MOC)

Gets to a mobile subscriber, the MSC analyzed using the dialed number, what type it is the called subscriber is ( mobile subscriber in its own network, mobile participants in a foreign network, fixed network subscriber, special phone number ) and builds the call to the subscriber on: is the case of mobile subscribers first the home HLR of the called subscriber demand, in which network and in which MSC area this is just; Fixed line subscribers and special numbers, the call is forwarded to a landline.

Number portability

These scenarios have become by introducing the possibility to keep the allocated number also with a change of provider or network operator, according complicated. Based on the network prefix can not be decided since the network to which a user belongs. To this end, a query in a specific subscriber database, called the Network Address registers required. This database is either on central network elements, such as the Signaling Transfer Point ( STP ) or network elements for service management, such as the Service Control Point (SCP ).

Recent Developments

3GPP Release 4

With the 3GPP specification for Release 4, the function of MSC on 2 systems was divided:

  • Mobile Switching Center Server (MSS ) for signaling and management of the mobile network
  • Media gateway ( MGW ) for receiving the data streams of the cellular network (voice )

Mobile Switching Center Server (MSS )

MSS includes all the functions for the control of the radio network, which includes the MSC. The functions of the MSS are

  • Location management of participants
  • Local management of subscriber profiles (Visitor Location Register (VLR ) )
  • Control of the call establishment and termination
  • Collection of call data for billing
  • Communication with other components of the cellular network

MSS is used to control the mobile radio network. It has only signaling interfaces to other mobile network elements to the radio network and the media gateway, which directs the mobile - data streams (voice, GPRS data).

Media Gateway (MGW )

About the Media Gateway, the data streams of the mobile network are routed (voice, data ). The control and steering of the data streams is hereby adopted by the MSS. The MSS are in this case the MGW to decide exactly which data stream is in which channel to channel to which output channel.

LTE networks

In LTE networks, the function of the MSC from the IP Multimedia Subsystem ( IMS) is applied.

Mobile telephony Mobility management#Location area Central Equipment Identity Register
577242
de