Question about IQ values

I use my customized antenna board (5 antennas on it) with the following IQ problem:

DF3 CTE[0]: samples count 45, cte type AOA, channel index 13, slot durations: 2 [us], packet status CRC OK, RSSI -1270

sample[0] I= -10 Q= 5
sample[1] I= 9 Q= -6
sample[2] I= -10 Q= 6
sample[3] I= 8 Q= -8
sample[4] I= -8 Q= 8
sample[5] I= 7 Q= -9
sample[6] I= -7 Q= 8
sample[7] I= 6 Q= -10
sample[8] I= -4 Q= 0
sample[9] I= 0 Q= 10
sample[10] I= -1 Q= -1
sample[11] I= 0 Q= -1
sample[12] I= 6 Q= 0
sample[13] I= 0 Q= 2
sample[14] I= 10 Q= -2
sample[15] I= -1 Q= 0
sample[16] I= -1 Q= -1
sample[17] I= 1 Q= -7
sample[18] I= 2 Q= 0
sample[19] I= -1 Q= -11
sample[20] I= 0 Q= 0
sample[21] I= -1 Q= 1
sample[22] I= -7 Q= -2
sample[23] I= -1 Q= -3
sample[24] I= -11 Q= -2
sample[25] I= 0 Q= -1
sample[26] I= 0 Q= 0
sample[27] I= -2 Q= 5
sample[28] I= -3 Q= 0
sample[29] I= -1 Q= 10
sample[30] I= -1 Q= -1
sample[31] I= 0 Q= -1
sample[32] I= 6 Q= 1
sample[33] I= -1 Q= 2
sample[34] I= 10 Q= 1
sample[35] I= -1 Q= 0
sample[36] I= -1 Q= -1
sample[37] I= 1 Q= -6
sample[38] I= 2 Q= 0
sample[39] I= 1 Q= -11
sample[40] I= 0 Q= 0
sample[41] I= -1 Q= 0
sample[42] I= -6 Q= -3
sample[43] I= 0 Q= -3
sample[44] I= -11 Q= -4

- Frequently the CTE report will report IQ value to be both zero. The RSSI in this report is not correct (due to an unsolved bug), the truth value of the RSSI in this report is about -300 (I place the beacon and the locator at a close distance).

- Note that even some other IQ value is not zero in the meanwhile, the amplitude or magnitude of them is low, causing trouble for the location of the device. However, as mentioned, the Tx and RX sides were placed closely. The signal should be strong, which means the amplitude of IQ value should large, too. 

Background:

I am using my customized PCB board with nrf52833 chip and an 8 port rf switch, the antenna is panel antenna.  Software envir is the SDK v1.8.0. 

 Thanks, Looking for your answer.

Parents
  • Hi,

    Could you tell me based on which example have you implemented your project.? Is this the AOA connectionless beacon.? Also, to get an accurate location estimation, 5 antennas might be a little less. It is recommended to use at least 2x3 antenna array to get an okay resolution but it is always recommended to use more.  Also, RSSI could vary greatly depending on a lot of external factors. If there is a lot of activity on the 2.4 GHz band, it will cause interferences between the devices.

    Kind Regards,

    Swathy

Reply
  • Hi,

    Could you tell me based on which example have you implemented your project.? Is this the AOA connectionless beacon.? Also, to get an accurate location estimation, 5 antennas might be a little less. It is recommended to use at least 2x3 antenna array to get an okay resolution but it is always recommended to use more.  Also, RSSI could vary greatly depending on a lot of external factors. If there is a lot of activity on the 2.4 GHz band, it will cause interferences between the devices.

    Kind Regards,

    Swathy

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