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CC1352P: Communication Interference issues for Sub Ghz devices

Expert 1750 points

Replies: 8

Views: 141

Part Number: CC1352P


I have two CC1352R and CC1352P boards communicating with each others using sub GHz at 868 freq band, 50 KBPS speed with 12 dBm tx power with Nonbeacon mode and another two boards(same as first) communicating with each others using sub GHz at 868 frequency band with 12 dBm Tx power,

we are using only by default channel mask(channel 0) particularly copying channel number and network details including sensors joined to the network, into external flash and retrieve back after restart in collector instead of using usual network creation) for both networks. we use SDK 3.3 and ccsV9.2. we are testing in India(Asia) and our client is in Germany(Europe) has faced the following. 

We are getting the following problems

1. Collector -> Sensor Communication failure beyond 30m (for collector sending data requests to sensors and sensors are not receiving)
2. When Multiple Collectors Power on - Sensor Communication failure with the paired collector(Collector interference)
3. Collector <-> Sensor communication duplicates beyond 10 m for specific sensor-collector combination

Note: We are using Custom boards for collector and Sensors. My hardware team ensured that they used hardware as per TI design for CC1352R and CC1352P. 

The following test cases are done by our client.

1. Collector Association test with sensors. Result: Some time passed and some times failed.

2. Communication test between sensor and collector at a 10-meter distance. Result:  Duplicates from the sensor to Collector and collector to sensor happens

3. Communication test between sensor and collector beyond the 30-meter distance. Result: Communication between sensor and collector halts.

And we test the same scenarios which our customer tested in Germany and found all test cases are working fine in India. But Our client-facing the above issues.

Can you provide any solution approach for us to debug the issue faced by our client?

  • Genius 17965 points

    Hello Haricharan,

    Can you confirm that these results are not reproducible when communicating between CC1352P + CC1352P and CC1352R + CC1352R?



  • In reply to AB:

    Hi AB,

    With CC1352P as Collector and CC1352R as a sensor, the tests are conducted in India and Germany. In India those tests are pass but in Germany, those do not completely fail but some interference issues may happen I believe. Does 4G LTE of Germany have any impact on SUB GHz communications because those are in the same frequency whereas in India that is not the case?

    Anyways CC1352R as collector and cc1352R as a sensor we will test and get back.

  • Genius 17965 points

    In reply to Haricharan sarpatwar:

    Hello Haricharan,

    If the same software+hardware is working in India but not Germany, I might suspect that the cellular bands might be interfering with the communication. can you modify the channel mask to include more channels? If the collector starts a channel on a different channel it may mean that channel 0 has too much noise.



  • In reply to AB:

    Thank you very much AB, I appreciate response from you, I will try changing channel mask and come back. Mean while can I get a root cause for the problems mentioned.

    We are testing with 5 collectors and the same scenario as mentioned above and kept logs we too got with one system

    For collector Transaction expired

    And for sensor NO Ack many times

    If we could know the RCA it will be easy implement solutions

  • In reply to Haricharan sarpatwar:

    Hi AB,

    Can we use instead of 4 channel mask all the channels for both sensor and collector, so that if more no of collectors are there then also there won't be any channel noise issue. If you can say the reasons for much noise other than SUB 1 GHz network it will be an advantage for us, to search for solutions.

    Thanks & Regards


  • Genius 17965 points

    In reply to Haricharan sarpatwar:


    Yes you can enable every channel in the mask to allow the collectors to search for a cleaner channel. It may slowdown joining time, since the sensor will go through every channel looking for a collector to join, but once it joins it should be fine.

    Can you check the noise floor at the channel 0-4 using smartRF studio?

    check the Rssi of every packet coming in and also the continuous RX noise floor?

  • In reply to AB:

    Hi AB,

    We Changed the channel mask to 4 channels. We had some interesting results.

    we took 3 Collectors and loaded code in one by one ensuring each cm gets different channels and found the same.

    Later erased with all unprotected sectors for Collector2 and Collector3 by using uniflash tool.

    Found CM2 and is allocated to Channel 2, and Collector3 also assigned channel 2.

    we printed Channel,PanId and Shortaddress of Collector 2 and collector 3.

    For both

    Channel - 2

    PanID - 1 and shortaddress - 0xAABB

    we allowed open network in both collector2 and collecter3.

    Sensor joined to Colelctor2 we printed collector MAc id in sensor log.

    Sensor is sending data to both collectors. If I poweroff Collector2 even then sensor is sending data to collector3.

    When both Collectors are off then the sensor became orphan.

    I power on collector 3 sensor is still in orphan when I restart sensor then it rejoined to collector and sending data to collector3.

    Whether this behaviour is expected?

    The following are some queries I had.

    1. For Collector 2 and Collector 3 the 

    Channel - 2

    Pan ID - 1

    Short address - 0xAABB

    How does sensor knows parent CM?

    2. In which channel, sensor will send data?

    Note: Sensor received channel2 when joined, But we observe In DataReq, sensor sending through channel 0.

    3. Sensor always sends in channel 0 or it has to send data with its parent collector channel only?

    4. Why 2 collectors are receiving sensor data? Is this because of same channel?

    Thanks & Regards



  • Genius 17965 points

    In reply to Haricharan sarpatwar:


    You need erase all sectors to delete previous network data, that is why the behaviour did not change until you erased the flash. 

    You can undefine NV_RESTORE inside the define folder if you want the collector to start from scratch everytime it resets.

    The reason why multiple collectors receive data from 1 sensor is because they are both in the same channel, same panID and same network key.

    Once the sensor is orphaned, it will start its orphan mode scanning, this can take a while since the default parameters call for a back time of 30 seconds and 5 minutes. You can adjust these values on the syscfg menu.

    Also, if you wish for the collector to restart and join another collector on reset, you can do the same as the collecotr and undefine the NV_RESTORE predefine.