回复： LTE/Wi-Fi Coexistence Application Example Question

[douglasekim]

This question relates to the NI LTE/Wi-Fi or LAA/LTE-U Coexistence Application Example that is based upon the LTE & 802.11 Application Frameworks.  

If I just open the testbed and run it, things work. However, the LAA mode seems to only work for specific combinations of settings. In particular, LAA works with the "FDD Custom" TX/RX frame structure. If I try TDD, TDD Custom, FDD, or any other available option, the LAA mode doesn't sync at all.

Moreover, In the FDD Custom mode that works for LAA, the CRC doesn't always pass. The throughput where the CRC passes may be 53 Mbps but the PDSCH overall throughput is around 60 Mpbs. I'm running the demo cabled, and I never have the CRC fail during the normal LTE AFW or if I switch over to the LTE-U mode in the testbed.

Do you have any insight into what the purpose of the "FDD Custom" configuration is for and why the sync for LAA only works with that mode? And do you know why the CRC doesn't always pass for the LAA mode?

I appreciate your help.

Thanks,

Chance T.

[douglasekim]

For the LAA mode, only "FDD custom" works.

In case LTE-U mode is selected, "FDD custom" leads to LTE-U, "FDD"/"TDD 3 5"/"TDD 5 5" lead to conventional LTE.

Pls disregard the "TDD custom" mode at all.

Regarding the CRC errors: Those might happen as frequency estimation/tracking algorithm can not rely on the LTE frame structure anymore. Hence, it might happen that the CRC becomes wrong for the very first subframe of a TX opportunity. The higher the TXOP value is chosen, the lower the CRC error rate becomes.

[BUPT_HouJia]

hello！I'd like to ask you a question I've met.I tried WiFi coexistence with WiFi, it's  incredible that the two WiFi throughput from 35.8  increased to 37.7 at the same time. Have you ever tried？

[douglasekim]

Hi BUPT_HouJia,

Thank you for your question.  In order to determine if your results can be reproduced by NI, would you please describe your system setup both in terms of HW (the number of nodes), and the software settings you are using.  Please also provide screen shots.  

[Bh@nu]

Hi Team,

Could you please explain the parameters of LBT cat 4 and cat 2 which are used in LTE LAA implementation using lte application framework.\

Please find the attached screenshots.

Regards,

Bhanu

[Air_Frantz]

Hello Bhanu,

The page below has information regarding the implementation of LBT Cat 4:

http://www.ni.com/en-us/innovations/white-papers/16/real-time-lte-wi-fi-coexistence-testbed.html [no longer available]

[Wayne004]

Hello AirFrantz

I am doing my research on LTE/WiFi coexistence and I have a questuon that how can I get the LTE-WiFi coexistence Application Example about the white paper mentioned above? Now, I only have the normal NI LTE Framework, which is not enough to support the experiments I expected.

Sorry to bother you, I appreciate your help！！

[mb78]

I have designed this LTE/WiFi Coexistence Application example using the latest application framework 19.5. But when i am building bitfile, build failed on the last step with reason "Design did not meet timing. Reduce the data paths with the longest delay" Did i add extra feedback node to resolve this issue.