-I modify the name of the parameter "maxRS-IndexCellQual-r15" to "maxRS-IndexCellQualNR-r15" in structure,
otherwise it will be conflict with the Macro define "#define maxRS_IndexCellQual_r15 (16)" in asn1_constant.h
This is hack-level development.
With this commit you can do UDP DL traffic of say 100Mb/s over
a 5MHz link with one connected UE and the eNB should not crash
because of memory exhaustion. Of course on the receiver side
you won't get 100Mb/s and many many lost packets. But the system
should not crash. 1Gb/s does not work. So in any case try to
remain within some reasonable limits. There is no reason to
push more than twice the maximum achievable throughput of
the link.
This work is based on a patch proposed by Francesco Gringoli.
Running TCP DL traffic with one connected UE showed a lot of
fluctuations in throughput. After analysis it was found that
sometimes the RLC UM PDU was not correct. It contained one byte
more than it should. On the receiver side, the TCP packet
contained in the RLC packet seems to be rejected by the TCP
stack of the UE (it has one byte more than it should),
leading to a brutal reduction of the throughput, probably due
to some congestion detection in the TCP implementation.
Or something.
This hotfix seems to solve the problem. Using iperf in downlink
with a 5MHz eNB, we see no more fluctuations, the traffic is
very steady at 16.8Mb/s, as reported by the iperf server running
on the phone. (17.5 in the PHY plot of the T tracer.)
A rewrite of both the MAC and RLC UM packet generation is needed.
The code is way too complex for what it does and may contain
several similar problems that only trigger in specific rare
conditions.
phy_init_lte_ue_signal was renamed init_lte_ue_signal in openair1/PHY/INIT/defs.h
maybe it's the opposite that should have been done?
Functions used in one file and defined in another may have been
declared in the wrong header file.
The constant RLC_UM_SEGMENT_NB_MAX_LI_PER_PDU is set to 24. This is
too low. Running a downlink TCP iperf with a 10MHz or 20MHz cell
leads to lots of the following warning in the log:
[RLC][W][SN 792] Bad RLC header! Discard this RLC PDU (size=618)
The problem is that the uplink RLC PDU contains a lot of TCP ack.
We can see much more than 24 of them. The RLC layer is not happy
and discards the PDU.
Putting 256 for RLC_UM_SEGMENT_NB_MAX_LI_PER_PDU (arbitrarily chosen,
big but not too big) solves the problem, at least for 10MHz.
- import RRC ASN.1 defintions from the specifications
(file openair2/RRC/LITE/MESSAGES/asn1c/ASN1_files/RRC-e10.asn)
contrary to rel8/10, all modules have been imported, maybe it's too much
to refine in case of problems
- deal with rel14 in fix_asn1
- all code that was for Rel10 is now for Rel10/Rel14
- some incompatible changes (mostly in naming) were resolved in favor
of rel14, see in openair2/RRC/LITE/defs.h
- unsure about the rlc layer, some arrays have changed (values appended),
I only changed the definition and in tests in the code, I changed
the index limit, maybe it's not enough
Rel14 is the default compilation mode.
WEI-TAI CHEN