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Does Macro eNB perform s1-setup with MME per cell.

+2 votes

I have a doubt regarding S1 setup Procedure. As macro eNB can support multiple cells. so Does enb send s1setup request per cell or just once ?

posted Jul 3, 2013 by Vimal Kumar Mishra

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2 Answers

+2 votes

S1-AP is only TL association between eNodeB and MME.
According to 36.413, S1-Setup-Req only contains Global eNodeB id, Tracking Area codes and PLMN ids.
I am not very sure if an S1 link would carry SIB messages as it is something to do between eNodeB and UE as far as my knowledge goes and it would not have any bearing with S1-AP as such
Even if SIB info would be carried over S1, it would go as one of the IEs in the S1-AP message, whereas the S1-AP setup would always only mean setting up the link between eNodeB and MME and it would not have any bearing on the number of cells it is serving. Corrections welcome.

answer Jul 4, 2013 by Chandra Javalkar
0 votes

I am assuming that you are talking about S1AP interface and S1-Setup request
S1Setup request is between MME and Tower not with the cell. So logically it should be once...

answer Jul 3, 2013 by Salil Agrawal
If I refer SIB1 content then it has cellIdentity(28 bits) so should we consider that all cells supported by eNB has same cellIdentity (28 bits) string in sib1 since in S1 setup Req message macro eNB Id(PLMN+ 20 leftmost bits of cellIdenity) is sent out to MME. but ue location is reported to MME at cell level granularity( ECGI-> PLMN + cellIdentity). if MME doesn't know about all supported cell then what make sense to send cell level location reporting to MME ?
Ideally first 20 bits should be same, but let me cross-check...
Similar Questions
0 votes

Hi All,

I have a query regarding S1 setup procedure.
If MME receives S1 setup Request message from same eNB twice (Assuming the S1 connection is already up), what will be the behavior of MME in this case.
Will it erase both UE and non-UE related application data? Or does it send S1 setup failure message?

Thanks in advance.

+2 votes

I have a use case in which
ENodeB sends "S1-Setup Request" message to MME. TAC within the request is unknown for MME but at least one PLMN from the list of broadcasted PLMN is known by MME. How MME shall react ?

+3 votes

Does S1-SETUP procedure run for each cell supported by an eNodeB, if yes then why and if no then why not.

+3 votes

What MME shall perform when receiving S1 path switch request (changing tac and lac for the UE) after a NAS tau request. Shall MME respond to UE with TAU reject (which cause code ) or not ?

+1 vote

Generally MME serves a group of tracking areas and belongs to at least one PLMN.
Lets assume, MME receives S1-setup request from eNodeB with the list of supported TAs.
Now, there are three possibilities as captured below.
1. All supported TAIs match at MME
2. Not even a single TAI match at MME
3. Few TAIs match at MME

I want to know, what MME will do for case 2 and case 3 ? How it will respond to eNodeB ?
If MME responds with S1-setup failure then what would be the cause value ? I did not find any reference in 36.413 for these scenarios.