Why is tau in LTE?
Tracking Area Update(TAU) in LTE is similar to a Location Area Update/Routing Area Update in GSM and WCDMA. Normal TAU – It is initiated when the tracking area on which the UE is attached is different from the previously registered cell or when UE re-selects/does handover from 2G/3G to LTE.
How MME is derived?
The eNodeB derives the MME from the RRC parameters carrying the old GUMMEI and the indicated Selected Network. The eNodeB forwards the TAU Request message together with the TAI+ECGI of the cell from where it received the message and with the Selected Network to the new MME.
What is tau timer?
Periodic TAU Periodic tracking area updating is used to periodically notify the availability of the UE to the network. The procedure is controlled in the UE by the periodic tracking area update timer (timer T3412).
What is Tai list?
To explain this process further, a UE obtains a TAI list when it attaches to an LTE network. This list shows the tracking areas where the LTE network believes a UE is located and within which a UE can travel without TAU.
What is tau in 5g?
The two Mobility Management (MM) procedures that are essential to localize a specific UE and deliver data packets to that UE are known as Tracking Area Update (TAU) and Paging, which are burdensome to the system because of very high-volume traffic.
What is Tai in 5g?
Tracking Area identity (TAI): It is used to identify tracking areas. The TAI is constructed from the PLMN identity the tracking area belongs to and the TAC (Tracking Area Code) of the Tracking Area.
What is IMSI LTE?
IMSI is a unique ID that globally identifies a mobile subscriber. When a user subscribes to a mobile network, the user gets a device and a USIM card (SIM card) that has an IMSI in it. By then, the LTE network should already have the same IMSI registered as well. IMSIs are stored in an HSS and an SPR, the LTE entities.
What is TAC in telecom?
The Type Allocation Code (TAC) is the initial eight-digit portion of the 15-digit IMEI and 16-digit IMEISV codes used to uniquely identify wireless devices. The Type Allocation Code identifies a particular model (and often revision) of wireless telephone for use on a GSM, UMTS or other IMEI-employing wireless network.
What is the activeactive flag?
Active flag is a request by the UE to activate the radio and S1 bearers for all the active EPS Bearers by the TAU procedure. The UE’s ISR capability is included in the UE Core Network Capability element. The EPS bearer status indicates each EPS bearer that is active in the UE. The TAU Request message shall be integrity protected by the NAS-MAC.
Why does the UE send Tau requests to the Mme?
So, the UE, even when the TA is not changed, sends TAU Request messages to the MME periodically to announce “it is able to receive data”. Otherwise, the network believes the UE is not able to receive data and does not perform paging even when there is data traffic heading to the UE.
Is ksiasme included in a Tau request?
The TAU Request message shall be integrity protected by the NAS-MAC. KSIASME is included if the UE has valid security parameters. NAS sequence number indicates the sequential number of the NAS message.
What does Tau stand for?
LTE: Tracking Area Update Request The TRACKING AREA UPDATING(TAU) procedure is always initiated by the UE and is used for (some of) the following purposes: ยท Normal TAU: When the UE enters a tracking area that is not in the list of tracking areas that the UE previously registered in the MME