LTE FUNDAMENTALS

LTE FUNDAMENTALS

LTE/EPS Mobility Areas

Mobile Country Code(MCC):

(i)   MCC Represents the country that a entity belongs to!

(ii)  It’s a 12 bits.

o     Ex: 404, 405  India , 310  USA

Mobile Network Code(MNC):

(i)    MNC Represents the Network that a entity belongs to!

(ii)   It’s a 12 or 8 bits depends on MNC number.

Public Land Mobile Network(PLMN):

(i)    Represents a operator’s Network in a country!

(ii)   Either 20 bits or 24 bits.

 PLMN ID = MCC + MNC

o   EX1: 404 07 : IDEA A.P, 404 13: VODAFONE, A.P

o   EX2: 272 07 : ELR IRELAND , 310 13 : VERIZON, USA

                 

GUMMEI :Global Unique MME ID: Unique in the world. see 5G identities

MCC + MNC + MMEGID + MMEID
PLMN ID + MMEGID +MMEID

MMEIGID: It’s a MME group Id, When more than two IDs serve together to a set of common list of TAI. This arrangement is known as MME pool and make a Groups of MME.

GLOBAL ENB-ID: Unique in the world

        MCC + MNC + MACRO ENB ID

        PLMN ID + MACRO ENB ID

Cell Identifications: When the UE is in Connected State, Network Knows the UE’s Position at Cell Level!

(i)Cell Identification(CI):  Unique in a PLMN and 28 Bit Number

                                      

(ii)ECGI: Evolved Cell Global Identity: Unique in the World.

         ECGI = MCC + MNC + CI

         ECGI = PLMN ID + CI

                                     

(iii)PCI: Physical Cell ID: Used for Radio Operations
 -(0-503) 504 PCIs are repeated in a PLMN

 -Adjacent Cells must be configured with different PCIs.

TAI : Tracking Area Identity: Globally Unique

o   Tracking Area = Several Cells

o   PLMN Area = One or More Tracking Areas.

o   Each Area shall have an Unique Tracking Area Code - TAC

            TAI = MCC + MNC + TAC

            PLMN + TAC

o   Ex: 404 07 56, 404 07 72, 404 13 72, 310 13 72

o   Whenever UE shifts from one TAI to another TAI, it would perform an Tracking Area Update(TAU)

o   Network [MME] always maintains the present TAI of a UE whenever the UE is in Registered State!    

TAI Lists:

o  Network May Group the Tracking Areas into a TAI List and Requests UE to not report the Tracking Area Updates if its present in one of the TAI from the List!

o  So UEs need to perform TAU only if it enters into a TAI Which is not part of TAI List!

o  This feature is also called as Multi-Tracking Area Registration!

UE IDENTIFICATION NUMBERS

UE PERMANENT IDs:

·      IMSI: International Mobile Subscriber Identification

     IMSI = MCC + MNC + MSIN

     [OR] PLMN ID + MSIN

·      MS-ISDN(Mobile Subscriber- ISDN):Subscriber Number For ISDN Services[Only for CS Services]

     CC + NDC + SN

·      IMEI(International Mobile Equipment Identity):Unique Identity for Mobile Devices

     TAC + FAC + SN + SV

UE Temporary IDs: To see 5GNR UE identities

·         C-RNTI( Cell Radio Network Temporary Identity):Allocated by eNB when UE Connects to it!

·         GUTI( Global Unique Temporary Identity):Allocated by MME when UE Successfully attaches to it!

   MCC + MNC + MMEGID + MMEID + M-TMSI

·   eNB S1AP UEID, MME S1AP UEID

·   MME S11 GTPC TEID, SGW S11 GTPC TEID

·   SGW S5/S8 GTPC TEID, PGW S5/S8 GTPC TEID

·   SeNB X2AP UE ID, TeNB X2AP UEID: During HO

UE Temporary IDs Diagram:

UE STATES

·         RRC-IDLE <-> RRC-CONNECTED

·         ECM-IDLE<-> ECM-CONNECTED

·         EMM-DEREGISTERED <-> EMM-REGISTERED