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LTE-U/LAA Application Example, 2 USRPs

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LTE-U/LAA Application Example, 2 USRPs



I am working with the LTE-U/LAA Application Example, "LTE_WIFI_coex_2_0_1_RC1_20170629." I'm using it in LAA mode, and when I do a cable loopback from the TX port to the RX port, things work as expected.


I am trying to RX the data on another USRP.  I understand that only DL is implemented for this project, but I was hoping to run the same design on both, but only do the RX on one of them. My setup is illustrated below. 





When running the project, the DL RX intermittently syncs on my 40 MHz USRP as expected for LAA, but it can't decode PDCCH. I am running the receiver on the 160 MHz eNB so that it can measure the spectrum for the LBT.  The carrier is definitely broadcasting and shows up on the 40 MHz USRP UE RX Power Spectrum.


Any thoughts? Are there some things that are passed internally on the FPGA that requires it to be on the same device? 




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Re: LTE-U/LAA Application Example, 2 USRPs



Was your problem addressed with the update provided on this other thread?

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Accepted by topic author ctarver
09-06-2017 08:12 AM

Re: LTE-U/LAA Application Example, 2 USRPs



I discussed this with NI offline. Although there wasn't a good solution to improve the reliability, I've found that using a clock sync cable between the two helped. This isn't ideal, but for my purposes is fine. 


The other thread was about the timing in the LTE-U. This problem was a separate issue that was resolved via changing a register. 



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Re: LTE-U/LAA Application Example, 2 USRPs


My name is Mohith a student at TU Darmstadt. I am very new to the field of LTE. I have been give a reference design of LTE Design USRP Rio v2.0.1 and labview communication 2.0. I have created an instance of the design and am trying to analyze the reference code, but not making any progress in getting the exact idea the code is intended to do. So do you have any documents explaining this reference design clearly stating the usage of these blocks. Do reply to 

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