Change USRP session parameters in RunTime

[Wired_]

I want to change some of the parameters of USRP RIO in runtime. Baically based on time.

1. Change receiver/trasmitter chain depending on case. If case 1 the USRP tranmits from a queue using RF0/TX1

Case 2: USRP receives using the same antenna.

How can I choose between RX and TX available with RF0 during runtime. After every T milliseconds RF1 changes between RX1 and TX1.

Thanks

[tcap]

Hello Wired,

Sadly, this functionality does not exist. R&D is aware of this limitation in LabVIEW Communications and they are working towards making an example in future versions of the product.

Regards,

[alexvoina31]

Is it possible to change the LO frequency during runtime execution ? For example if I have 2 USRPs communicating and another one transmitting on a neighbor frequency ( Tx1 <-> Rx1 2.4G , Tx2 -> 2.42 G) is it possible to apply some kind of frequency correction so that Rx1 will jump to the frequency of Tx2 ? 

[Phy_comm]

Yes you can use digital frequency shift. Where you take FPGA field of shift frequency (LO) from any of the project like, streaming or SISO TDD and them control shift from Host.

The shift is really fast as it's not hardware based.

[alexvoina31]

Wow thanks Phy_comm for your immediate reply!

I am trying to do this directly on the 802.11 app framework to implement some kind of a Handoff procedure. Are you sure there is no limitation in the "frequency hop" value ? Should it work for any frequency in the working range of the selected USRP model?

[Phy_comm]

No the jump should be +- half of bandwidth you are running on I believe. 

[alexvoina31]

Sorry for the rushed reply, I have read in the meantime the context help for the Frequency Shift function. It should be fine for me since I need a minimum hop of 20 MHz which is the requirement for the non-overlapping transmissions. Also the phy rate is at 250MHz. Thanks a lot for your help!

[Phy_comm]

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