Monday, July 19, 2010

Voice over LTE to have 3G support and emergency calls

Updated specifications of VoLGA Forum for its standard for Voice Over LTE have been released. The new specifications include mobile voice as well as SMS services over 4G and is different from the current standard which supports only data. The changes in the standard will bring VoLGA (Voice over LTE via Generic Access) which uses 3G, HSPA-based networks. Users also get an option for emergency calls even in the absence of a SIM card.

The just released standard will optimize voice-bearer routing. The forum has also issued host APIs for LTE devices.

Nineteen companies are members of the VoLGA Forum. Among them, LG, Motorola, Samsung, Cisco and HTC are the most important.

Many efforts are being made in order to standardize both calls and SMS on the LTE data network. They include the One Voice initiative of Verizon, AT&T, Alcatel-Lucent, Ericsson, Nokia, Siemens and Samsung.

Saturday, July 10, 2010

NAS Elementary procedures for EPS Mobility Management

The main function of the mobility management sublayer is to support the mobility of a user equipment, such as informing the network of its present location and providing user identity confidentiality

A further function of the mobility management sublayer is to provide connection management services to the session management (SM) sublayer and the short message services (SMS) entity of the connection management (CM) sublayer.

All the EMM procedures can only be performed if a NAS signalling connection has been established between the UE and the network. Else, the EMM sublayer has to initiate the establishment of a NAS signalling connection.

Types of EMM procedures
  • EMM common procedures
    • GUTI reallocation
    • Authentication
    • Security mode control
    • Identification
    • EMM information

  • EMM specific procedures
    • Attach and combined attach.
    • Attach.
    • Detach and combined detach.
    • Normal tracking area updating and combined tracking area updating (S1 mode only).
    • Periodic tracking area updating (S1 mode only).

  • EMM connection management procedures (S1 mode only)
    • Service request.
    • Paging procedure.
    • Transport of NAS messages;
    • Generic transport of NAS messages.