CA PCell and SCell RRC connection

4G LTE
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1

In CA pCell and Scell.
Is there only one RRC connection or SCell also have RRC to UE?
How UE connect with SCell.?
e.g. if there is 3CC and UE take 3 RRC connection license?

Please if any one can explain this concept.

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2

Only one RRC connection at the PCELL.
Licensing depends on what the counter accounts, and what the operator and vendor have agreed on.
A vendor may have a counter which accounts 3 times and a counter which accounts 1, in your example.

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3

Pcell is Primary Cell and he is responsible for RRC CONNECTION, Resource Allocation and Mobility Management.
In CA, there is only one RRC connection with PCC.
Main advantage of CA is to improve end user Throughput or double but depend on Carrier bandwidth and Increase capacity but prb utilization will increased.

For Scell addition and removal decided by
UE share measurement to Pcell its neighbour Scells based on that Pcell select best cell.
PCell which are based on mainly 2 switches: 1) UE Data Buffer Length(enodeB end)usually :6KB=48kbytes
2) UE Buffer time : 6ms.
Also consider
3) Scell measure quality better than A4 threshold

For Scell changes use A6 event for intrafrequency Handover.

All 2CC , 3CC Follow same procedure.

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My comments on PCell and SCell and difference between PCell CC & SCell CC:

PCell :

  1. PDCCH/PDSCH/PUSCH/PUCCH can be transmitted.
  2. Measurement and Mobility procedures are based on PCell.
  3. Random access procedure is performed over PCell.
  4. Cant not be deactivated.
  5. DL PCell & UL PCell are linked via SIB2.

SCell :

  1. PDSCH/PDCCH/PUSCH can be transmitted (Not PUCCH used) on Scell
  2. MAC Layer activation and Deactivation is performed on SCell.
  3. It can be CROSS SCHEDULED.

NOTE : By using the Cross scheduling in CA ,will reduce the interference in between the High Power ENB’S and Small cells by using the same frequency.

5

Cross scheduling means: Pcell can schedule DCI for Scell, right?

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Correct!

image

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BTW, as far as I know, no Cross Carrier Scheduling actually supported by LTE UEs or eNodeBs.

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From all log file I checked, DCI comes from all Pcell & Scell.
In case of cross-scheduling, it must be intra-enodeB CA, right?
Because inter-enb, it’s difficult for Pcell to know about resource status of Scell.