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AD9361 for an 8X8 MIMO system

I am planning to develop an 8X8 MIMO system based on the AD9361 agile transceiver.

I known that the evaluation board AD-FMCOMMS5-EBZ for a 4X4 MIMO system is available. Is a demo board of an 8X8 MIMO system under development? If yes, when it will be available and at what costs?

If it is not the case, has anyone developed an 8X8 MIMO system based on the AD9361? Does it require substantial design effort and re-design with respect to the reference AD-FMCOMMS5-EBZ design or the baseband processor HW and SW architecture can be adapted?

Thank you very much

  • Paolo:

    We do not have an 8x8 planned.

    I saw you were at a university - depending on how many people are on your team for the 8x8 system, and your schedule/budget, you might be better off using a commerical product:

    http://www.beecube.com/products/MegaBEE.asp

    - Robin

  • Robin:

    Thank you very much for your answer.

    What I am going to develop is not a conventional MIMO platform for communications. I have to check is the commercial product is sufficiently flexible for our research and compatible with the budget constraint.

    By the way, my original idea was to develop a AD9361-based 8X8 board within from 0.5 up to 1 year/man workpower of an experienced designer. Do you believe it is feasible, re-using part of the AD-FMCOMMS5-EBZ design?

    Paolo.

  • Paolo:

    You should be able to extend the fmcomm5 to do what you need. It's just a question of what sort of FPGA platform you can connect to.

    We designed the fmcomms5 to be able to use 2x LPC (low pin count) FMC connectors. This allows both the Xilinx ZC706 and ZC702 to work.

    For an 8 x 8 system, you may need 2 x HPC. I haven't really dug into it much, but it will be a lot of signals.

    It took ~4-5 months to develop the fmcomms5, but is/was a combination of HW, RF, HDL, kernel/driver software, user space (calibration). It's more than one person can normally do. On the ADI side - it was a team effort, it wasn't the same person doing all the work for 4 months straight. Sometimes the work overlapped, sometimes people were working on other things.

    Does that help?

    - Robin

  • Thank you very much, Robin. Your answer is valuable for me to estimate the requested effort.

    I guessed the key point for the extension is the FPGA and how to interface it.

    Unfortunately, here at university we cannot count upon a well-trained design team and sometimes one has to do several different jobs. Maybe a less experienced designer (e.g. a PhD student) can work together with a more experienced in this project. Anyway, now I have a better picture of the resources needed, and of the design effort.

    Thank you a lot!

  • Based on my experience in product support, 8x8 MIMO transceiver design would be a challenging one even for a team of specialist in individual areas in a commercial environment. Typically, performance issues like spurious and noise near the end of a design cycle can take as long to troubleshoot and correct as the initial part of the development. Your approach to use commercially available hardware and software building blocks is a very good approach.

  • hi sir.. i am planning for 8x8 ab9361 on single board..pls can u help regarding the requirement of fmc connectors.. i mean will 1 hpc 1 lpc work or we require 2 hpc??

    also can u throw some light on how to obtain RF phase sync without using external LO

  • For an 8 x 8 system, you may need 2 x HPC but please check the number of signals between AD9361 and BB.

    We use a feature called MCS(multi-chip synchronization) to synchronize multiple chips which have similar LOs and synchronize the phase.

    Refer below link for phase synchronization with multiple devices.

    https://wiki.analog.com/resources/eval/user-guides/ad-fmcomms5-ebz/multi-chip-sync#rf_phase_difference

    https://wiki.analog.com/resources/eval/user-guides/ad-fmcomms5-ebz/phase-sync