Hi All!
To aid in urban search-and-rescue I am building a small backpack that trained rats can carry while finding survivors beneath rubble. I am using WiFi Halow to stream video and audio from this device to operators on the surface. The device seems to be working fine, but the distance I am able to achieve seems limited. Currently I can stream video through one floor to the apartment below me, but not two, which seems far off from the theoretical maximum. Even at 1m distance the AP reports a low RSSI of -40 to -50 dBm.
The HaLow module is connect to an NXP i.MX8M-Mini via SDIO. When I run iw dev I get the followng. It show the correct SSID and txpower, but the wrong channel, something in the 5GHz range.
root@ucm-imx8m-mini:~# iw dev
phy#0
Interface wlan0
ifindex 2
wdev 0x1
addr 00:0a:52:09:18:ad
ssid RescueRatStation
type managed
channel 136 (5680 MHz), width: 20 MHz, center1: 5680 MHz
txpower 21.00 dBm
I have set the country-code to US through /etc/modprobe.d/morse.conf. Running iw reg get gives:
root@ucm-imx8m-mini:~# iw reg get
global
country 00: DFS-UNSET
(2402 - 2472 @ 40), (N/A, 20), (N/A)
(2457 - 2482 @ 20), (N/A, 20), (N/A), AUTO-BW, PASSIVE-SCAN
(2474 - 2494 @ 20), (N/A, 20), (N/A), NO-OFDM, PASSIVE-SCAN
(5170 - 5250 @ 80), (N/A, 20), (N/A), AUTO-BW, PASSIVE-SCAN
(5250 - 5330 @ 80), (N/A, 20), (0 ms), DFS, AUTO-BW, PASSIVE-SCAN
(5490 - 5730 @ 160), (N/A, 20), (0 ms), DFS, PASSIVE-SCAN
(5735 - 5835 @ 80), (N/A, 20), (N/A), PASSIVE-SCAN
(57240 - 63720 @ 2160), (N/A, 0), (N/A)
phy#0 (self-managed)
country US: DFS-invalid
(902 - 904 @ 2), (N/A, 30), (N/A), AUTO-BW
(904 - 920 @ 16), (N/A, 30), (N/A), AUTO-BW
(920 - 928 @ 8), (N/A, 30), (N/A), AUTO-BW
(5650 - 5690 @ 40), (N/A, 30), (N/A), AUTO-BW
(5170 - 5330 @ 160), (N/A, 30), (N/A), AUTO-BW
(5490 - 5650 @ 160), (N/A, 30), (N/A), AUTO-BW
(5735 - 5895 @ 160), (N/A, 30), (N/A), AUTO-BW
This shows some Halow channels listed, but manually setting the interface to use any Halow channel seems restricted:
root@ucm-imx8m-mini:~# iw dev wlan0 set channel 1
kernel reports: Channel is disabled
command failed: Invalid argument (-22)
root@ucm-imx8m-mini:~# iw dev wlan0 set channel 2
kernel reports: Channel is disabled
command failed: Invalid argument (-22)
root@ucm-imx8m-mini:~# iw dev wlan0 set channel 3
kernel reports: Channel is disabled
command failed: Invalid argument (-22)
root@ucm-imx8m-mini:~# iw dev wlan0 set channel 4
kernel reports: Channel is disabled
command failed: Invalid argument (-22)
root@ucm-imx8m-mini:~# iw dev wlan0 set channel 6
kernel reports: Channel is disabled
command failed: Invalid argument (-22)
root@ucm-imx8m-mini:~# iw dev wlan0 set channel 7
kernel reports: Channel is disabled
Now my question is two-fold:
- Could this be causing the range of the halow link to be degraded even though it is physically working near the 900 MHz band?
- If so, how can I solve this issue?
Thanks for your help!
(misread the design used).
