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LAUNCHXL-CC26X2R1: DTM: AOA CTE Test

j f
Prodigy 20 points

Part Number: LAUNCHXL-CC26X2R1

Hi,Team,
I used two LAUNCHXL-CC26x2R1s and an AOA boosterpack to preview the DTM. The one LAUNCHpad is to be receiver and has mount with AOA boosterpack; the other one is to be transmitter. I rebuilded the ble5stack example “host_test”project(the symbol RTLS_CTE_TEST has been pre-defined) and loaded hex files to launchpad respectively. For launchpad with aoa booterpack, I have moved C14 to C24 to select JSC ant and moved C12 to C15 to use GND to filter the PCB Ant signal.
When everything is ready，as shown in FIG, I sent DTM HCI command according to BLE core v5.2 spec . When I used a logic analyzer to measure DIO27, DIO28, DIO29, DIO30 by referring to the antenna switch truth table, I found that either the antenna array #1 or #2 was not switched continuously in the entire test period. For detail, only when I finished sending the command "HCI_LE_Receiver_Test" , the antenna array switch only for a moment. If this is the case, the DTM AoA CTE receiver test will not be convincing.
Can you suggest me how to solve this problem and privide more related DTM AoA CTE details for me?

  • 0
    TI__Mastermind 44420 points

    Hello,

    I have assigned an expert to comment.

    Best Regards,

    Jan

  • +1
    TI__Guru** 101540 points

    Hi,

    Could you please provide a logic trace of the antenna switching? It would also help if you could provide a BLE trace.

    The test mode, enables the sender to send LE test packets with appended CTEs. In other words, the CTEs are not transmitted continuously.

    The antenna switching only occurs during the reception of the CTEs. No antenna switching is expected to occur outside of the reception of the CTEs.

    Best regards,

  • 0 in reply to Clément
    Prodigy 20 points

    Thank you for your reply!
    The logic trace of the antenna switching is shown in the figure below, which is one of the traces between DIO28~DIO30. I personally think that when I sent the command "HCI_LE_Transmitter_Test [v3]", the sender will send LE test packets with appended CTEs continuously until the command “HCI_LE_Test_End” is to be sent. So the receiver will receive LE test packets with appended CTEs continuously and will filter out other LE test packets.
    But things are not what I thought, I did two sets of experiments:
    1) .Transmitter: "HCI_LE_Transmitter_Test [v3]" (this will send AOA CTEs).
    Receiver: "HCI_LE_Receiver_Test[v3]" (this will accept AOA CTEs).
    After 30 seconds, I send "HCI_LE_Test_End" to Receiver, and then check the number of packets received.
    2). Transmitter: "HCI_LE_Transmitter_Test [v1]" (this will send common LE test packets without CTEs).
    Receiver: "HCI_LE_Receiver_Test[v3]" (this will accept AOA CTEs).
    After 30 seconds, I send "HCI_LE_Test_End" to Receiver, and then check the number of packets received.
    The results show that the number of packets received in the two experiments is basically the same. This cannot prove the AOA CTE test. Is this the right test? Are there other test methods?

  • 0 in reply to j f
    TI__Guru** 101540 points

    Hi,

    I am not sure what is the goal of your tests. But, I am not sure you would test much by only counting the number of received packets. I am telling you this, because, even without antenna switching or pretty poor antenna design this test would pass. (I am not telling one of these issues exist on your design, I am telling you would not catch these kind of issues).

    I would rather recommend to review the RF-PHY tests related to AOA required for Bluetooth certification. The test you should consider are:

    • BV-15-C [Output power]
    • BV-16-C [Carrier frequency offset and drift at 1 Ms/s]
    • BV-05-C [IQ Samples Coherency at 1 Ms/s with 2 μs Slot]
    • BV-11-C [IQ Samples Dynamic Range at 1 Ms/s with 2 μs Slot]

    When it comes to DTM, I think your understanding is correct - the command HCI_LE_Transmitter_Test command allows you to send out the LE test packets with appended CTEs until you call HCI_LE_Test_End.When using HCI tester, the commands Send_HCI_LE_Enhanced_Cte_Transmitter_Test , Send_HCI_LE_Enhanced_Cte_Receiver_Test and Send_HCI_LE_Test_End are the proper commands.

    To be clear, these commands do not send an uninterrupted tone. I would recommend to review the BLUETOOTH CORE SPECIFICATION Version 5.2 | Vol 6, Part F, §4.1.7, to clear all remaining doubts regarding LE direct test mode.

    If relevant, let me point you to the Bluetooth RF-PHY qualification we have completed for AoA: https://launchstudio.bluetooth.com/ListingDetails/127623. It may help you to qualify by similarity your product - please contact your Bluetooth Qualification Consultant (BQC) for details regarding this topic. . You may also want to review our app note about qualification https://www.ti.com/ble-qualification.

    To finish, I am out of the office until the end of July. I will not answer on E2E during this time. If my message did not completely answer your questions, I would then kindly ask you to open a new thread using the button Ask a related question. Make then sure to summarize the unresolved issues, that way other engineers will pick up the thread.

    Best regards,