6.7 KiB

Raw Blame History

Bandwidth: Configured vs Negotiated Display

New Feature

The WiFi connection info now shows both configured and negotiated bandwidth, making it easy to spot when the connection didn't get the bandwidth you requested.

Example Output

Perfect Match (80MHz)

I (13022) main: WiFi CONNECTED - BLUE LED solid
I (13022) main:   SSID:      'ClubHouse'
I (13032) main:   Band:      5GHz
I (13032) main:   Bandwidth: 80MHz (VHT80) (negotiated) - configured: VHT80  ← Match!
I (13032) main:   Channel:   120
I (13042) main:   RSSI:      -32 dBm

Mismatch (Configured 80MHz, Got 20MHz)

I (13022) main: WiFi CONNECTED - BLUE LED solid
I (13022) main:   SSID:      'ClubHouse'
I (13032) main:   Band:      5GHz
I (13032) main:   Bandwidth: 20MHz (HT20) (negotiated) - configured: VHT80  ← MISMATCH!
W (13032) main:   ⚠ Bandwidth mismatch! Configured VHT80 but negotiated 20MHz (HT20)
W (13032) main:   Check: router channel width setting, channel selection, RF interference
I (13032) main:   Channel:   120
I (13042) main:   RSSI:      -32 dBm

Match (40MHz)

I (13022) main: WiFi CONNECTED - BLUE LED solid
I (13022) main:   SSID:      'ClubHouse'
I (13032) main:   Band:      5GHz
I (13032) main:   Bandwidth: 40MHz (HT40) (negotiated) - configured: HT40  ← Match!
I (13032) main:   Channel:   44
I (13042) main:   RSSI:      -35 dBm

What It Shows

Field	Description
Negotiated	What bandwidth the device actually connected at
Configured	What bandwidth you requested via config_device.py
Warning	Appears when there's a mismatch

Why Mismatches Happen

Configured VHT80 → Negotiated HT20

Common causes:

Router channel width - Router set to 20MHz or "Auto" picked 20MHz
Channel not 80MHz capable - Some channels don't support 80MHz width
DFS channel issues - Dynamic Frequency Selection interference
Interference - RF environment forced downgrade
Router doesn't support 802.11ac/ax - Old router (802.11n only)

Fix:

# Check router settings:
# - Channel width: 80MHz (not Auto or 20/40MHz)
# - Channel: 36, 44, 52, 100, 108, 116, 149, 157
# - Mode: 802.11ac or 802.11ax

# Try non-DFS channel
# Set router to channel 36 or 44 (most reliable for 80MHz)

# Then reconnect
./config_device.py -p /dev/ttyUSB1 -i 192.168.1.81 \
  -s ClubHouse -b 5G -B VHT80

Configured HT40 → Negotiated HT20

Common causes:

Router channel width - Router set to 20MHz only
Interference - Adjacent channels occupied
2.4GHz congestion - Too many overlapping networks

Fix:

# On router:
# - Channel width: 40MHz
# - Channel: 1, 6, or 11 (2.4GHz) or any 5GHz channel

# Reconnect
./config_device.py -p /dev/ttyUSB1 -i 192.168.1.81 \
  -s ClubHouse -b 5G -B HT40

Troubleshooting Guide

Step 1: Check WiFi Driver Log

The most reliable indicator is in the WiFi driver log:

I (12652) wifi:connected with ClubHouse, aid = 3, channel 120, BW20(BELOW, C1)
                                                                  ^^^^

BW20 = 20MHz
BW40 = 40MHz
BW80 = 80MHz

This is what actually happened (ground truth).

Step 2: Check Our Display

Our display gets this from the API:

I (13032) main:   Bandwidth: 20MHz (HT20) (negotiated) - configured: VHT80

Should match the WiFi driver log.

Step 3: If Mismatch, Check Router

For 80MHz on 5GHz:

Router channel width = 80MHz (not Auto)
Channel = 36, 44, 52, 100, 108, 116, 149, or 157
No DFS interference (try channel 36 or 44)
802.11ac or 802.11ax enabled

For 40MHz:

Router channel width = 40MHz minimum
Adjacent channels available
Low interference

For 20MHz:

This is the fallback - always works
Good for congested areas
Best for stability

Bandwidth Performance

Bandwidth	Throughput (5GHz)	Use Case
20MHz (HT20)	~130 Mbps	Congested areas, maximum range
40MHz (HT40)	~270 Mbps	Good throughput, less congestion
80MHz (VHT80)	~530 Mbps	Maximum throughput, clean RF

Testing Procedure

Test VHT80 (80MHz)

# 1. Configure router for 80MHz
# Channel: 36 or 44 (non-DFS)
# Width: 80MHz
# Mode: 802.11ac or 802.11ax

# 2. Configure ESP32-C5
./config_device.py -p /dev/ttyUSB1 -i 192.168.1.81 \
  -s ClubHouse -b 5G -B VHT80

# 3. Check connection
idf.py -p /dev/ttyUSB1 monitor

# Look for:
# I (13032) main:   Bandwidth: 80MHz (VHT80) (negotiated) - configured: VHT80
# No warning should appear!

# 4. Test throughput
iperf -c 192.168.1.81 -t 30
# Expected: ~500 Mbps

Test HT40 (40MHz)

# 1. Configure router for 40MHz
# Width: 40MHz

# 2. Configure ESP32-C5
./config_device.py -p /dev/ttyUSB1 -i 192.168.1.81 \
  -s ClubHouse -b 5G -B HT40

# 3. Check connection
# Should see: Bandwidth: 40MHz (HT40) (negotiated) - configured: HT40

# 4. Test throughput
iperf -c 192.168.1.81 -t 30
# Expected: ~270 Mbps

Implementation Details

New API Function

wifi_cfg.h:

bool wifi_cfg_get_bandwidth(char *buf, size_t buf_size);

Returns the bandwidth string from NVS ("HT20", "HT40", "VHT80").

Display Logic

main.c:

// Get configured from NVS
char configured_bw[16] = {0};
wifi_cfg_get_bandwidth(configured_bw, sizeof(configured_bw));

// Get negotiated from WiFi API
wifi_bandwidth_t bw = /* from esp_wifi_get_bandwidths() */;

// Compare and warn if mismatch
if (strcmp(configured_bw, "VHT80") == 0 && bw != WIFI_BW80) {
    ESP_LOGW(TAG, "⚠ Bandwidth mismatch!");
}

Warning Conditions

A warning appears when:

Configured VHT80 but negotiated HT20 or HT40
Configured HT40 but negotiated HT20
Configured HT20 but negotiated HT40 or VHT80 (rare)

Files Modified