LTE: Why "Handover Type" IE is included in both handover messages i.e Handover Required and Handover Request ?

649 views

I was looking into IEs of handover required and handover command messages defined in 36.413 specification.
Sending "handover type" in handover required message towards the MME make sense but again get back the same IE in handover command message from MME in the handover command message, I could not make out the reason behind it.
Can someone please explain the reason of presence of "Handover Type" IE in the handover command message when eNodeB already knows which type of request it sent to MME for an UE ?

Is there any possibility MME can change the type of Handover in handover command message ? If yes then what could be the scenarios ?

posted Nov 19, 2016 by Harshita

Looking for an answer? Promote on:

Facebook Share Button

Twitter Share Button

LinkedIn Share Button

Similar Questions

+3 votes

LTE: Why does "CS Fallback Indicator" IE present in UE Context Modification Request ?

What happens for an UE at MME, which gets triggered "UE Context Modifcation Procedure" for "CS fall back" ?

+2 votes

LTE handover: Why does "TAC" required as part of "Target Id" IE within the forward relocation request message ?

In case of S1-handover with the MME relocation, source MME sends an information "Target Identification" to target MME.
What the target MME does by receiving TAC, when an enodeb can be identified uniquely by using combination of (PLMN + Macro/Home ENodeB) ?

Can someone tell me what the purpose behind to send TAC as part of Target Id IE ?

+5 votes

LTE: Why presence of Tracking Area Identity (TAI) and E-UTRAN CGI (ECGI) IEs is mandatory in Uplink NAS Transport ?

Uplink NAS transport message is used between eNodeB and MME to pass NAS messages between UE and MME transparently.
Since eNodeB has already communicated TAI and E-CGI as part of "Initial UE message" and MME knows current serving (cell and tai ) of UE then why both IEs are mandatory in Uplink NAS transport. I think it should be optional and it should be included in the message when there is a change in serving (cell or tai or both).

+5 votes

Who does radio bearer mapping during UTRAN to E-UTRAN handover where source RNC is pre-release 8

Who does radio bearer mapping during UTRAN to E-UTRAN handover where source RNC is pre-release 8 ? From the spec what I can see is if the source RNC is pre release 8, then it sends Source RNC to Target RNC transperant container (which I believe carries all the radio bearer related information). The EPC will transperantly forward it to the Target enodeB. Does the target EnodeB do the mapping from RNC container for the radio bearer in the new RAT ?

+1 vote

LTE HO : Why two MME UE S1AP IDs present within the S1-AP HO Request message ?

I found two MME UE S1-AP IDs i.e. MME UE S1AP ID (Mandatory) and MME UE S1AP ID 2 (optional).
I got why mandatory one is present but what's use of optional one.

Can someone please explain it ?

...