QM33120 uwb channel interference

Wireless Connectivity Ultra-Wideband
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Hi everyone,
This is my first post here — nice to meet you all.

I’m testing TWR (Two-Way Ranging) using one QM33120WEVB and one QM33110WEVB, each connected to an STM32L433-Nucleo64 board. I configured the boards to use channel 5 and channel 9 respectively for communication.

The purpose of this test is to eventually use two UWB modules placed close to each other while operating on different channels (5 and 9) to avoid interference.

Since the devices are on different channels, I expected no ranging to occur at all. However, at close range, distance measurements are unexpectedly succeeding.
When I move the devices further apart, the ranging stops — as originally expected.

Is this behavior normal? Could there be cross-channel leakage or some other explanation for this?

For reference, I’m using the following example source codes from DW3_QM33_SDK_1.0.2:

  • Initiator: ex_05c_ds_twr_init_sts_sdc
  • Responder: ex_05d_ds_twr_resp_sts_sdc

Any advice or insights would be greatly appreciated.
Thanks in advance!

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Hi @Hichael ,

Nice to meet you, too. Welcome to Qorvo Tech Forum.

You have an interesting problem. I don’t know the root cause of this issue, but it is worth trying different preamble codes on different channels, which would provide further isolation between channels.

Please let us know about your progress.

Kind regards,
Emre

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This doesn’t surprise me, I’ve seen similar on the DW1000 using channels 3 and 5. The receiver is fairly sensitive and no filters are perfect, if you hit it with enough power it’ll pick up the signal even if it’s outside the expected band. Due to the inverse square law at very short ranges the power is a huge amount higher than you’ll see at a normal ranges and leakage like this can happen.

As suggested, different preamble codes will normally fix this, it massively reduces the sensitivity of the receiver to the transmitted data. Using a different PRF would further reduce the risk of this happening.

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