Configuring Dual-Band Dual-Concurrent (DBDC) Operation on the Sona MT320

  1. Introduction
  2. Requirements
  3. DBDC Architecture & Performance Mechanics
    1. Airtime Efficiency vs. Spatial Stream Allocation
  4. System Setup & Interface Configuration
    1. Stop Background Services and Reset Driver
    2. Verify Hardware Support
    3. Instantiate the Secondary Virtual Interface
  5. Testing the Setup
    1. Configure and Launch 5 GHz Access Point (wlan0)
    2. Configure and Connect 2.4 GHz Station (wlan1)
  6. Verification
    1. Sending and Receiving Data
Sona MT320Tungsten510 SMARC

Introduction

This guide describes how to configure and demonstrate Dual-Band Dual-Concurrent (DBDC) operation on the MediaTek MT320 platform running Linux.

DBDC allows a single MT320 module to operate on two distinct frequency bands (e.g., 5 GHz Access Point and 2.4 GHz Station/Client) simultaneously on separate hardware MAC/PHY pipelines, eliminating the latency and throughput penalties associated with single-MAC time-slicing (Multi-Channel Concurrent / MCC).

This guide was created using the Ezurio Tungsten 510 SMARC SOM platform equipped with the optional Sona MT320 m.2 1420 solder-down module with two MHF4L antenna ports (453-00176). This guide also applies to the m.2 1420 RF trace variant (453-00177) or the m.2 2230 variant (453-00178) connected to a MediaTek EVK.

Requirements

  • Tungsten510 SMARC with MT320 (T510_SMARC_SOM_8r16e_MT320_2M)
  • Universal SMARC Carrier Board Kit (SMARC_CAR)

  • Custom Yocto Scarthgap image

  • Terminal software to communicate with the SOM (e.g., Minicom, Tera Term, PuTTY)
  • Antennas connected to both MHF4L ports (MIMO/Dual-Band antennas)
  • External 2.4 GHz Access Point (or Smartphone Hotspot) for client association testing
  • Wireless client device to associate with the MT320 5 GHz Access Point

DBDC Architecture & Performance Mechanics

Airtime Efficiency vs. Spatial Stream Allocation

Understanding how DBDC splits internal hardware resources is key to managing expectations for link rates and throughput:

  • No Airtime Penalty: Unlike Multi-Channel Concurrent (MCC) modes that rapidly time-slice a single MAC between channels (causing massive latency spikes), DBDC allocates dedicated MAC and RF processing chains to each band. Both bands transmit and receive at the exact same time.
  • Spatial Stream Reduction (2x2 to 1x1): The MT320 is a 2x2 MIMO Wi-Fi 6 (802.11ax) chip. In single-band mode, both streams unite on one frequency. In DBDC mode, the internal architecture divides the 2x2 radio into two independent 1x1 single-stream radios: MAC 0 (wlan0): Dedicated 1x1 stream for 5 GHz (AP mode, up to 40/80 MHz channel width). MAC 1 (wlan1): Dedicated 1x1 stream for 2.4 GHz (STA mode, 20 MHz channel width).

System Setup & Interface Configuration

Stop Background Services and Reset Driver

Before instantiating virtual interfaces, stop background network managers that may lock interface states:

systemctl stop NetworkManager wpa_supplicant connman hostapd 2>/dev/null 
killall NetworkManager wpa_supplicant connman hostapd 2>/dev/null

#Bring physical link down

ip link set wlan0 down

Verify Hardware Support

Check the physical radio index assigned by the kernel (usually phy0 or phy2):

iw dev

Inspect the radio's capability matrix (replace phy0 with your active phy index):

iw phy phy0 info

Look for the valid interface combinations section at the bottom of the output:

valid interface combinations: 
      * #{ managed, P2P-client } <= 2, #{ AP, P2P-GO } <= 1, #{ P2P-device } <= 1,
      total <= 3, #channels <= 2 {code}

Key Indicator The presence of #channels <= 2 alongside #{ AP... } <= 1 and #{ managed... } <= 2 explicitly confirms that the kernel driver and MediaTek firmware support running an Access Point and a Station concurrently on two independent frequency channels. {info}

Instantiate the Secondary Virtual Interface

By default, the driver only exposes wlan0. Create a secondary virtual interface (wlan1) tied to the same physical radio (phy0), and assign it a unique MAC address:

# Create secondary managed interface wlan1 on phy0 (replace phy0 with your active phy index)
iw phy phy0 interface add wlan1 type managed
# Assign a unique MAC address to wlan1 (required by MediaTek driver)
ip link set wlan1 address e8:cb:f5:00:01:8f

# Bring both interface link states UP
ip link set wlan0 up 
ip link set wlan1 up

Verify that both interfaces are enumerated under the same radio:

root@tungsten-510-smarc:/etc# iw dev 
phy#0 
  Interface wlan1 
    ifindex 6 
    wdev 0x3 
    addr e8:cb:f5:00:01:8f 
    type managed 
    txpower 3.00 dBm 
    multicast TXQ: 
      qsz-byt qsz-pkt flows drops marks overlmt hashcol tx-bytes tx-packets 
      0       0       0     0     0     0       0       0        0 
      
      Interface wlan0 
        ifindex 4 
        wdev 0x1 
        addr e8:cb:f5:00:01:8e 
        type managed 
        txpower 3.00 dBm 
        multicast TXQ: 
          qsz-byt qsz-pkt flows drops marks overlmt hashcol tx-bytes tx-packets
          0       0       0     0     0     0       0       0        0

Testing the Setup

Configure and Launch 5 GHz Access Point (wlan0)

Create a basic 5 GHz hostapd configuration file (/etc/hostapd-5g.conf):

interface=wlan0 
driver=nl80211 
ssid=MT320-5G-AP 
hw_mode=a 
channel=36 
country_code=US

Launch hostapd on wlan0 in background mode:

hostapd -B /etc/hostapd-5g.conf

Configure and Connect 2.4 GHz Station (wlan1)

Create a wpa_supplicant configuration file targeting a 2.4 GHz network or mobile hotspot (/etc/wpa_supplicant-2g.conf):

ctrl_interface=/var/run/wpa_supplicant 
update_config=1 
ap_scan=1
network={ 
  ssid="YOUR_2G_HOTSPOT" 
  psk="YOUR_PASSWORD" 
  key_mgmt=WPA-PSK SAE 
  ieee80211w=1 
}

Connect wlan1 to the 2.4 GHz Access Point:

wpa_supplicant -B -i wlan1 -c /etc/wpa_supplicant-2g.conf

Verification

Run iw dev to confirm both interfaces are actively linked across different frequency bands:
root@tungsten-510-smarc:/etc# iw dev 
phy#0 
  Unnamed/non-netdev interface 
    wdev 0x5 
    addr ea:cb:f5:00:01:8e 
    type P2P-device 
    txpower 3.00 dBm 
    Interface wlan1 
      ifindex 6 
      wdev 0x3 
      addr e8:cb:f5:00:01:8f 
      ssid LairdTest 
      type managed 
      channel 1 (2412 MHz), width: 20 MHz, center1: 2412 MHz 
      txpower 3.00 dBm 
      multicast TXQ: qsz-byt qsz-pkt flows drops marks overlmt hashcol tx-bytes tx-packets 
                     0       0       0     0     0     0       0        0       0 
    Interface wlan0 
      ifindex 4 
      wdev 0x1 
      addr e8:cb:f5:00:01:8e 
      ssid MT320-5G-AP 
      type AP 
      channel 36 (5180 MHz), width: 20 MHz (no HT), center1: 5180 MHz 
      txpower 3.00 dBm 
      multicast TXQ: 
        qsz-byt qsz-pkt flows drops marks overlmt hashcol tx-bytes tx-packets 
        0       0       0     0     0     0       0       0        0 {code}

Sending and Receiving Data

To complete runtime verification:

Obtain an IP address on wlan1 via DHCP:

dhcpcd wlan1

Ping an external gateway while simultaneously streaming data from a client connected to MT320-5G-AP:

ping -I wlan1 8.8.8.8 -c 5

Result: Ping latency on wlan1 will remain stable (<10 ms) without packet drops or channel switching interruptions, proving true hardware-level DBDC execution.