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

Question

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 ?

Answer 1

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 2

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...

Comments

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 ?

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Ideally first 20 bits should be same, but let me cross-check...