Table of Contents
OpenAirInterface Community Q&A
General
Q1: Whats is OpenAirInterface (OAI)?
A1. OAI is an open-source hardware and software wireless technology platforms (simulation, emulation, and realtime) for deployment of mock network with high level of realism.
Q2: What are the supported technologies / systems?
A2. OAI provides a full experimental LTE implementation (Rel 8, partial Rel 10) in real time under realtime Linux optimized for x86 and with interworking functions. It includes EUTRAN (eNB and UE) and EPC (MME, xGW, and HSS). Currently, the project is working closely with the community to evolve the software towards future 5G releases of 3GPP. OAI has several 5G strategic vectors,
Q3: What are the supported HW platforms?
A3. Eurecom EXMIMO II and NI/ETTUS B210/X300, BladeRF, LMSSDR.
Q4: Who can use OAI?
A4. Being an opensource platforms, it is available for use by researchers from academic institutions, industry and government.
Q5: who is building OAI?
A5. OAI was initially developed by EURECOM, and have received funding from the European commision and French Government (see our history for more details). Currently, it is managed by the OpenAirInterface Software Alliance (OSA at www.openairinterface.org). OSA has several industrial/non-profit members; see the OSA members list for more details.
Q6: Does OpenAirInterface work with the ETTUS N210?
A6. Short answer: No. Long answer: The software should run, but the reference on the N210 is not at a frequency that can generate the required 7.68/15.36 MHz sampling. You should be able to get the OAI eNB to work with the OAI UE running at the wrong sampling rate though. We have never tried this since we don't have an N210.
Q7: What RF considerations are needed to run OAI?
A7. You need a duplexer and RF cables, antennas to work correctly. The RF parts should match correctly the band/RF frequency in which you are running the system. For more details, see the duplexer section on OAI System Requirements page.
Q8: What are the CPU requirements?
A8. It is best to run it on latest Intel Core i5/i7 with minimum of 4 cores. For more details, see the OAI System Requirements page.
Q9: What are SW Requirements?
A9. You need Ubuntu 14.04 or later running natively on the computer. At the time of writing (October 2018), we are intensively testing OAI on Ubuntu 16.04 LTS. There are specific requirements also on the kernel for OAI. For more details, see OAI SW Support page.
Q10: What are the UE Requirements?
A10. None theoretically, but it is best to use the phones that we have tried. Some phones bought from carriers have a wrapper that does not allow proper connection with OAI. It is best to buy unlocked phones but not from carrier but directly from 3rd party vendors on amazon/ebay. The SIM card tools are also listed here. If you try a phone not listed in above page, please let us know so we can add to gitlab page.
Q11: Do you have tutorials?
A11. Yes, a bunch at Tutorials page.
Q12: How do I contribute/report bugs?
A12. You need to sign the license agreement and then follow the gitlab workflow/coding guidelines to submit your branch for merging. For more details, see the How to Contribute page.
Q13: Do you have Continuous Integration framework?
A13. Yes, we have a CI framework that builds several variants on different systems, run simulators, phy tests. It also remotely controls UEs, EPC, eNBs and runs throughput tests. You are welcome to integrate it on your site and report issues on the mailing list. For more details, see the eNB CI page. As a contributor, you will receiving notifications on your merge requests. See the presentation made during ETSI-OAI joint workshop.
Q14: Are there any specific settings I have to enable on phone?
A14. Yes, you have to put the phone in LTE ONLY mode. You also have to set the APN in cellular settings to "oai.ipv4" if you use OAI EPC or to something else depending on your EPC configuration.
Q15: What config files do I use as a starting point?
A15. For USRP, $OPENAIR_DIR/targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.tm1.usrpb210.conf
For BladeRF, $OPENAIR_DIR/targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.tm1.bladerfx40.conf
For LMSSDR, $OPENAIR_DIR/targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.tm1.lmssdr.conf
For EXMIMO2, $OPENAIR_DIR/targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.tm1.exmimo2.conf
Q16: Can I use the above config files for any band?
A16. No. The config files above are only for band 7. SDR needs calibration for other bands. We have calibrated some of SDR platforms for other bands. You can look in folder for config files for other bands, $OPENAIR_DIR/targets/PROJECTS/GENERIC-LTE-EPC/CONF
Note: Please do not change arbitrarily TX/RX gains settings as they affect other LTE parameters.
Q17: Sometimes the phone will not want to connect to OAI. What is the problem
A17. Try to avoid phones bought from a certain carrier. They have a wrapper that will block other networks, for example OAI. Here is another solution, but try at your own risk, https://lists.eurecom.fr/sympa/arc/openair5g-user/2016-06/msg00076.html
Q18: I get error, "problem Receiving samples". What do I do?
A18. This error means that there is real-time issue with sample acquisition. If you are using USRP B210, then It happens as USB3 transfers are very sensitive to real-time performance. You should make sure all the steps related to CPU sleep, etc in HW/SW configuration are followed here, https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/OpenAirSoftwareSupport, https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/OpenAirKernelMainSetup#ubuntu-14043-ltslinux-kernel-version-319-recommended.
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You can also turn off WiFi/Bluetooth driver or in extreme case run your Linux without X Windows. Also, make sure your USRP is connected to USB3 port. If the problem persists, try doing USRP TX/RX benchmark tests and try to run OAI in 5 MHz(set N_RB_DL = 25) in eNodeB config file. You need to use latest i5/i7 (4 core minimum) PC for running OAI to avoid these kind of issues. You can also play around with CPU Affinity (see build_oai -h) to partition CPUs between lte-softmodem and USRP threads.
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If the issue persists, and the USRP or any other SDR is connected via USB3, then disconnect all the other USB devices from the eNB and work on it from remote session. The other USB devices can create negative impact on performance. Or you can buy USRP x310 and connect it via PCIe interface which is more reliable. http://www.ettus.com/product/details/X310-KIT
Q19: Phone is connected but does not want to accept IP Address.
A19: This might be due to mismatch of APN settings, https://lists.eurecom.fr/sympa/arc/openair5g-user/2016-10/msg00076.html
Useful Links
Q1. where I can get a copy of OAI SW?
Q2. Is there any automated build tool and how to use?
A2: see OpenAirInterface Usage.
Q3. How to start experimenting ?
A3. see AutoBuild
Q4. is there any vm image?
A4. Yes, but only for troubleshooting openair-cn installation. https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/HowToConnectCOTSUEwithOAIeNBNew#example-vmware-image-with-working-core-network-installation