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LTE: When 7 bit or 12 bit long PDCP SN is being used for PDCP PDU ?

+4 votes

Which factor derives this 7 bits or 12 bits long PDCP SN for PDCP data PDU carrying user data ?
Is it run time configurable for an UE ? or one time configuration.

posted Nov 26, 2013 by Vikram Singh

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2 Answers

0 votes

Its one time configuration, RRM will be configuring whether the data will be going on AM, UM. Accordingly it will be configuring the PDCP SN .

answer Dec 24, 2013 by anonymous
0 votes

u can set only 1 of them , not both of them for user plane PDCP Data PDU

answer May 21, 2017 by Eray Madrid
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+1 vote

I would like to change PDCP SN to 12 bits ( 7 bits is current) but not clear the effect.

From my understanding, if i increase the PDCP size to 12 bits (4096) for UE side it would be easier to decode packets correctly because sequence number will be identified with more bits.

What is your opinion?

Also since we increase the header for PDCP sn then data payload will be smaller so we can affect the throughput.

+2 votes

I found 1st bit which is used to indicate that packet carrying Data/Control information. My question is that why first bit is used even packet itself known as "PDCP Data PDU".

0 votes

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+1 vote

As per 3gpp 36.322 Release 12.0 RLC specification, Extended RLC LI field = 15 bit is newly included in AM mode.
Can anyone please explain, exactly in what condition this 15-bit LI value will be used.

0 votes

Assume UE's is in handover state and data calling,after successful handover will target ENB continues with the same SN which is of old ENB SN or will it change to new SN?