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fon909
2011-11-23, 01:12 AM
Hi,

Can anyone please explain the difference between RLC Tput and MAC HS Tput, and also confirm which one of the two will have higher value and why?

Thanks.

jayk
2011-11-23, 06:02 AM
Hi,

Can anyone please explain the difference between RLC Tput and MAC HS Tput, and also confirm which one of the two will have higher value and why?

Thanks.

MAC-hs PDU are derived from RLC PDU's. Mac-hs PDU includes additional Header + Padding bits. So throughput of Mac-hs is higher than that of RLC tput.

zeezzoo
2011-11-23, 07:32 AM
Mac-HS is a lower layer than RLC ==> the PDU for Mac-HS has additional bits which are the Mac Header . RLC Layer is in the RNC . Mac-HS layer is in the NodeB .

in case of R99 : the retransmission is done by the RNC's RLC Layer ( there's no Mac-HS in the protocol stack) . For HSDPA the Retransmission is done by Mac-HS layer instead of RLC . so if you conducted an HSDPA DT you will see MAC-HS Throughput is higher than RLC Layer throughput (sometimes a big difference if you have a bad radio condition [bad CQI] causing more retransmissions) .

PS : in hsdpa the retransmission can be also done by RLC Layer in the below cases :
- the NodeB miss interpret a NACK message set by the UE .
- Maximum # of Mac-HS retransmissions is reached for a given packet (the max number of Mac-HS Retransmission is set by a parameter on the nodeB level )
- during the HSDSCH serving cell change rthe NodeB flushes the Mac-HS buffer and the RLC sends the packet again to the new NodeB .

Hope it's usefull
BR,

anupumts
2011-11-25, 03:58 PM
So how large can the difference be on this one . I am getting difference of about 2Mac-HS and 500Kbps on RLC. Is that possible/

jan74
2011-11-25, 09:53 PM
Mac-HS is a lower layer than RLC ==> the PDU for Mac-HS has additional bits which are the Mac Header . RLC Layer is in the RNC . Mac-HS layer is in the NodeB .

in case of R99 : the retransmission is done by the RNC's RLC Layer ( there's no Mac-HS in the protocol stack) . For HSDPA the Retransmission is done by Mac-HS layer instead of RLC . so if you conducted an HSDPA DT you will see MAC-HS Throughput is higher than RLC Layer throughput (sometimes a big difference if you have a bad radio condition [bad CQI] causing more retransmissions) .

PS : in hsdpa the retransmission can be also done by RLC Layer in the below cases :
- the NodeB miss interpret a NACK message set by the UE .
- Maximum # of Mac-HS retransmissions is reached for a given packet (the max number of Mac-HS Retransmission is set by a parameter on the nodeB level )
- during the HSDSCH serving cell change rthe NodeB flushes the Mac-HS buffer and the RLC sends the packet again to the new NodeB .

Hope it's usefull
BR,

Curious about the RLC Layer transmissions here. Are you saying that after the PDU is discarded due to Max Retransmissions by the HS Scheduler, the RLC layer can send it again? Which vendor is that with?

zeezzoo
2011-11-25, 10:32 PM
@jan74 (http://www.finetopix.com/member.php?49757-jan74)
i read that in huawei ran 12 .
but i think it should be the same for other vendors . isn't it ??

zeezzoo
2011-11-25, 10:35 PM
@anupumts (http://www.finetopix.com/member.php?54064-anupumts)
in the DT i came across some problematic areas where CQI was bad and i had about 400 Kbps (Average) between RLC & Physical layer throughput .