How does the EnodeB know if a UE supports carrier aggregation

Question

I have a 3 part question
1) How does the EnodeB know if the user equipment supports carrier aggregation or not?
2) If a UE does not support carrier aggregation does it mean it’s a Release 9 or lesser compliant UE?
3) If the answer to question 2 is yes , then how does the UE not supporting carrier aggregation(release 9 or lesser UE) decode a DCI message sent from a EnodeB that is currently supporting LTE A(Release10) , as the DCI message (say DCI format 0) contains extra bits?

Comments

Answer to 1 question:- UE will send UECapabilityInformation to Network with all supported band combination. I think there is a  IE (RF_paramter_v1020) which will contain supported band information. You can check 36.331 for details.

Answer to 2 Question:- All release 10 UE does not support Carrier Aggregation.  And other thing all release9 & Rel8 will not support CA capability.

Answer to 3 Question:-  UE is still able to decode PCell Downlink , and Uplink but UE is not aware about SCell parameters, Even if you add SCell on Rel9 device that will be ignored. So UE will never attempt to decode SCell.

I hope this helps. Let me know in case you have more questions.

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Thanks for your reply. I have found most of the parameters in 36.331 IE (UE-EUTRA-Capability-v1020-IEs) based on your inputs . This solves my problem.
I just need to figure out how these are passed on from the MAC to Phy of EnodeB. Please do provide your inputs incase of any.  (for example say, UE supports CA in DL or in UL parameter)

Answer 1

1) The information about capabilities of UE is gathered during attach procedure, the Carrier Aggregation bands and bandwidth information is also transferred. [check UE-CapabilityRAT-ContainerList (3GPP 36.311)]

2) Since Carrier Aggregation is not a mandatory feature so we can not say if UE is Release 9 or lessor if it does not support CA.

Comments

Thanks for your reply. I would like to know if there is any specific parameter that is shared with the Phy(l1) of enodeB that tells it whether the UE supports CA in UL\DL?