Differences of Mobility Management Between an EPS

Differences of Mobility Management Between an EPS
Network and a 2G/3G Network

Added Identity:

• globally unique temporary identity (GUTI): It is assigned by the
  MME and is globally unique. A GUTI consists of the following two parts:
  • Globally unique MME identifier (GUMMEI): A GUMMEI consists of
    a mobile country code (MCC), a mobile network code (MNC), and an MME
    identity.

  • M-temporary mobile subscriber identity (M-TMSI): A 32-bit M-TMSI
    uniquely identifies a UE in an MME.

    
    

    The GUTI can be implicitly
    allocated in the attach or tracking area update (TAU) procedure or
    explicitly allocated in the GUTI reallocation procedure.

    
    
  
  
• Tracking area identifier (TAI): A TAI consists of an MCC, an MNC,
  and a tracking area code (TAC).

• TA List: A TA List consists of several tracking areas (TAs),
  as shown inFigure 1.

  
  
  • When a UE moves among TAs belonging to the same TA List, the TAU
    procedure is not triggered.
  • When the paging procedure is triggered, the UE is paged in all
    eNodeBs related to TAIs belonging to all TA list.
  • When the MME sends the Attach Accept, TAU Accept, or GUTI Relocation
    message to the UE, these messages include the TA List.