What are various types of handover supported in LTE?

Question

Can someone please explain the in details ?

Answer 1

This query can have various answer one would be based on the nodes which is being changed or not changed like -

1. Inter Cell (only cell is changed not the enodeB)
2. Inter EnodeB (enode B is also changed in addition to (1))
3. Inter MME (MME is also changed in addition to (2))
4. Inter RAT (LTE to UMTS)

But more obvious answer here would be S1 based handover or X2 based handover for this question. When source and target eNodeB has direct link then X2 based handover is triggered else it would have S1 based handover. There are few variations of S1 handover like "S1 based handover without MME relocation", "S1 based handover with MME relocation".

Let me know if you are looking something different.

Comments

Hi Salil,

I think there should be word "inter" in place of "intra" where ever you have quoted it. e.g. Inter cell = Intra EnodeB.  i.e. cells change within a EnodeB , EnodeB does not change.

Thanks & Regards:-)

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In the intra MME (S1 based) and Inter MME (X2 based)handover  their is another flavor where the SGW changes (SGW relocation)

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Thanks Ashutosh for pointing out my bad :)
@Saurabh: Thanks for adding SGW angle completely missed the point.

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Thanks everyone for clearing my doubt.

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Hi Saurabh/Salil ,
Inter MME handover is a variant of S1 based or X2 based handover ?
I see contradiction between Salil's & Saurabh's statements ......
And can someone throw more light on handover mode where SGw also changes ?

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First thing , S1 handovers take place when there is not X2 link between the source enodeb and target enodeb.
Now this may or may not involve MME change , If the source and target enodebs belong to different MMEs then its Inter MME , If they are connected to the same MME then its Intra-MME.
Now next thing , if the S1 handover is Inter-MME , It may or may not involve a SGW relocation .
When the source and target enb are connected to different MMEs and SGWs then the S1 handover is with SGW relocation