Cedric Roux
3f8c8b73e2
When t_poll_retransmit expires we need to consider an SDU for retransmission. We used to take the first SDU (which could be a segment, not a full SDU) of the wait list and put it in the retransmit list. When testing with some UE (Amarisoft UE) a bad behavior was detected. This is what happens for the SDU with SN 6 (for illustration purpose). The gNB is sending an SDU in several pieces (it is segmented). slot n: rlc sn 6 [1 .. 119[ p=0 RECEIVED slot n+x: rlc sn 6 ]120 .. 180[ p=0 RECEIVED slot n+x+y: rlc sn 6 ]181 .. 210] p=1 not RECEIVED Then when t_poll_retransmit expires rlc retransmits only the PDU of slot n (with p=1 this time) and the UE replies with ack 6. So nothing happens on the gnb side. (We would have expected ack 7 + nack 6 181..end.) Then after t_poll_retransmit expires again rlc retransmits only PDU of slot n and the UE still replies with ack 6. This goes on forever (or some other timeout occurs.) The logic is now changed. When t_poll_retransmit expires we transfer all the SDUs in the wait list having the same SN as the head of the wait list into the retransmit list. Testing with Amarisoft UE, it seems to work properly.
OpenAirInterface License
It is distributed under OAI Public License V1.1.
The license information is distributed under LICENSE file in the same directory.
Please see NOTICE file for third party software that is included in the sources.
Where to Start
Not all information is available in a central place, and information for specific sub-systems might be available in the corresponding sub-directories. To find all READMEs, this command might be handy:
find . -iname "readme*"
RAN repository structure
The OpenAirInterface (OAI) software is composed of the following parts:
openairinterface5g
├── charts
├── ci-scripts : Meta-scripts used by the OSA CI process. Contains also configuration files used day-to-day by CI.
├── CMakeLists.txt : Top-level CMakeLists.txt for building
├── cmake_targets : Build utilities to compile (simulation, emulation and real-time platforms), and generated build files.
├── common : Some common OAI utilities, some other tools can be found at openair2/UTILS.
├── doc : Documentation
├── docker : Dockerfiles to build for Ubuntu and RHEL
├── executables : Top-level executable source files (gNB, eNB, ...)
├── maketags : Script to generate emacs tags.
├── nfapi : (n)FAPI code for MAC-PHY interface
├── openair1 : 3GPP LTE Rel-10/12 PHY layer / 3GPP NR Rel-15 layer. A local Readme file provides more details.
├── openair2 : 3GPP LTE Rel-10 RLC/MAC/PDCP/RRC/X2AP + LTE Rel-14 M2AP implementation. Also 3GPP NR Rel-15 RLC/MAC/PDCP/RRC/X2AP.
├── openair3 : 3GPP LTE Rel10 for S1AP, NAS GTPV1-U for both ENB and UE.
├── openshift : OpenShift helm charts for some deployment options of OAI
├── radio : Drivers for various radios such as USRP, AW2S, RFsim, ...
└── targets : Some configuration files; only historical relevance, and might be deleted in the future