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CCS/LAUNCHXL-CC1310: Low range - Collector/Sensor example application in 868MHz Long Range Mode

Peter Jones97
Intellectual 335 points
Part Number: LAUNCHXL-CC1310
Other Parts Discussed in Thread: CC1310

Tool/software: Code Composer Studio

Hi,

we are benchmarking the long range mode using two Launchxl-CC1310 dev. kits connected through USB to a PC. First we are running Packet TX/Packet RX setup using SmartRF Studio 7 using the following settings;

Frequency; 868MHz

Output power; 14dBm

Setting Name; 5 kbps, SimpleLink Long Range (20kchip/s, 2-GFSK, conv. FEC r=1/2 K=7, DSSS SF=2, Tx dev: 5kHz, Rx BW: 49kHz)

Using this we see an expected range if we compare to ITU indoor model for office environments.

However, we would like to use the TI 15.4 stack configured to long range mode to be able to connect several sensors to a collector and monitor stability, range etc. I have imported the collector/sensor from C:\ti\simplelink_cc13x0_sdk_2_10_00_36\examples\rtos\CC1310_LAUNCHXL\ti154stack and modified the code in CCS according to;

/*! Setting for Phy ID */
#define CONFIG_PHY_ID          APIMAC_GENERIC_ETSI_LRM_863_PHY_131

This has been done for both collector and sensor. After flashing the new firmware I was expecting to see the same range as when using SmartRF Studio 7 but the range is significantly degraded. I understand that the collector/sensor example is running 12dBm output power but the difference in range is larger than what a 2dB decrease in power can account for.

Q1) Should we not expect the same range in the above two cases? Any ideas on if I need to do additional modifications to the sensor/collector example to get the same range?

I have validated that we get successful tranfer of sensor data using 863.125MHz frequency in the sensor/collector example above but I can not get the Smart RF Sniffer Agent (v1.04.00) to capture any packets. I have one sensor, one collector running in the background (channel 0) and a third board with sniffer fw that is connected to the smart RF sniffer agent. I have tried using configuration "IEEE 802.15.4g - Simplelink Long Range 5 Kbps - 868 MHz - Freq Band" with channel number set to 0 in the sniffer agent without success. When I run the sniffer I am not seeing any packets being captured.

Q2) Is there any reason why this should not work? Are there any modifications I need to do to get this up and running?

Best Regards

Peter

  • 0
    TI__Guru 58425 points

    Hi Peter,

    From what I can tell the PHY settings used in both cases is the same so you should be able to get the same range in both cases (taking the 2dB difference into account). I will ask some colleagues if there is any known issues with LRM and the TI 15.4 stack that could explain this.

    Can you try to use 14 dBm TX power in the TI 15.4 stack and compare those results? You will have to add the "CCFG_FORCE_VDDR_HH" define and change "CONFIG_TRANSMIT_POWER" to 14.

    Regarding the sniffing, I just tried this out myself and I was able to sniff the packages when using the LRM with the same settings. What I did was to simple install Packet Sniffer 2, flash the corresponding firmware and connect to the device. I was then able to capture packets using Wireshark as described in the docs.

  • 0 in reply to IUsedToBeARealPerson (M-W)
    Intellectual 335 points
    Hi M-W,
    Thanks for the quick reply! I did check using 14dBm output power but without any big improvement.
    I do not know if there is a lower threshold setting in the sensor/collector app for some reason? With SmartRF Studio we did observe a PER of about 10-20% at the location where the sensor/collector stopped working but for the demo I simply see that the collector stops reporting the sensor ID without any additional info.

    Ideally I would like to use the 15.4 stack to log RSSI/PER on serveral sensors at the same time but as far as I understand there is no such demo?!

    Best Regards,
    Peter
  • 0 in reply to Peter Jones97
    TI__Guru 58425 points
    Hi Peter,

    I see. I will try to get some tests done on this and get back to you when I got more information on this. When the collector stops reporting, if you again move the sensor into the "working range", will it start to receive again?

    There is some ways to read out the RSSI in the 15.4 stack but there is no examples of this available. If you search the forum you should be able to find a few threads talking about the 15.4 stack and RSSI, I will link to some of the more recent threads here below that you could check out:

    e2e.ti.com/.../681817

    e2e.ti.com/.../685612
  • 0 in reply to IUsedToBeARealPerson (M-W)
    TI__Guru* 86241 points
    Hi
    Can you please provide info regarding what M-W asked about? When the collector stops receiving, does it start to receive again once you move the units closer together or does it stop permanently?
    The problems you are experiencing with the sniffer, can that be related to chip revision? The 50 kbps settings are valid for both old and new devices, but the SLR settings will only work for PG2.1. If you have a PG2.1 device that you can use as sniffer, you should be able to check the RSSI. Do you see a difference if you transmit with Studio compared to with the sensor application?

    BR
    Siri
  • 0 in reply to Siri
    Intellectual 335 points
    Hi,
    when the collector stops receiving it can not receive again when I go within range. I have to reset the sensor for it to start working again.

    I am using PG2.1 and as far as I can tell the RSSI shows the same value for Studio and sensor application.

    Best Regards
    Peter
  • 0 in reply to Peter Jones97
    Intellectual 335 points
    Hi again,
    I got my hands on another board and went outside to an abandoned air strip and from what I can see now there is no big difference between sensor/collector and Studio so I am assuming it was something wrong with my initial setup.
  • 0 in reply to Peter Jones97
    TI__Guru 58425 points
    Hi Peter,

    That is nice to here, out of curiosity, do you also see the improvement indoors?
  • 0 in reply to IUsedToBeARealPerson (M-W)
    Intellectual 335 points

    Hi,

    yes it does seem to correlate indoors as well. It is difficult to say exactly since we are only getting sensor IDs and there is of course the issue of multipath in a changing office environment but to the extent we can see it does match.

    The RSSI reading for a stand-alone board is never lower than -110-114dBm RSSI though so I am questioning if it is actually possible to achieve a sensitivity below~ -110dBm in a "real" environment. Do you have any specs on the antenna gain, NF of the receiver path or similar?

    Best Regards

    Peter 

  • 0 in reply to Peter Jones97
    TI__Guru* 86241 points
    When testing on our HW you should be able to receive packets down to the sensitivity limit (-119 dBm). Have you checked the noise floor in the environment you are testing? if the noise floor is higher than the sensitivity limit, this will reduce your sesnitivity. You can measure the noisefloor by selecting SLR settings in SmartRF Studio and then run cont. RX.

    BR

    Siri