The goal of this project is to implement a wireless mesh network that provides connectivity and multimedia services in a geographic area such as a small campus.

Mesh networking performance is directly related to the number of available radio channels. Particularly, a mesh node with one wireless LAN chipset is able to transmit and receive on a single channel. As a result, a wireless mesh network rarely can fully exploit the aggregate bandwidth available in the radio spectrum provisioned by the standards. For a scientific explanation of this problem, please refer to this research team page.

In order to overcome this problem, we implement in this project low cost multi-channel mesh devices consisting of a wireless router with an additional WLAN adapter.

• TP-Link MR3020 wireless router.
• USB WLAN adapter based on the Ralink RT5370 chipset.
• Raspberry Pi Model B.

Make sure you have the attitude adjustment release of OpenWRT on your TP-LINK MR3020. For more information on how to flash the firmware on your router and take basic control, please refer to this article.

Start by updating the package list and installing the necessary packages for the USB WLAN adapter.

root@MeshNode:~# opkg update
root@MeshNode:~# opkg install kmod-rt2800-lib kmod-rt2800-usb kmod-rt2x00-lib kmod-rt2x00-usb

Figure 1. MR3020 with WLAN adapter

Plug the WLAN adapter on the USB port of your routeur and verify that is detected:

root@MeshNode:~# wifi detect
config wifi-device  radio2
        option type     mac80211
        option channel  11
        option macaddr  00:e0:4c:81:88:8a
        option hwmode   11ng
        option htmode   HT20
        list ht_capab   GF
        list ht_capab   SHORT-GI-20
        list ht_capab   SHORT-GI-40
        list ht_capab   RX-STBC1
        # REMOVE THIS LINE TO ENABLE WIFI:
        option disabled 1
 
config wifi-iface
        option device   radio2
        option network  lan
        option mode     ap
        option ssid     OpenWrt
        option encryption none

Now, copy the detected WiFi modules into the wireless configuration of your MR3020.

root@MeshNode:~# wifi detect > /etc/config/wireless    

Your wireless configuration file should be similar to the following:

/etc/config/wireless

config wifi-device  radio0
        option type     mac80211
        option channel  11
        option macaddr  f8:d1:11:bd:62:ce
        option hwmode   11ng
        option htmode   HT20
        list ht_capab   SHORT-GI-20
        list ht_capab   SHORT-GI-40
        list ht_capab   RX-STBC1
        list ht_capab   DSSS_CCK-40
 
config wifi-iface        
        option device   radio0
        option network  lan   
        option mode     ap    
        option ssid     OpenWrt1
        option encryption none 
 
config wifi-device  radio1    
        option type     mac80211
        option channel  11      
        option macaddr  00:e0:4c:81:88:8a
        option hwmode   11ng             
        option htmode   HT20             
        list ht_capab   GF  
        list ht_capab   SHORT-GI-20
        list ht_capab   SHORT-GI-40
        list ht_capab   RX-STBC1   
 
config wifi-iface                         
        option device   radio1            
        option network  lan   
        option mode     ap    
        option ssid     OpenWrt2
        option encryption none 

Check that both antennas are working:

root@MeshNode:~# wifi up
Configuration file: /var/run/hostapd-phy0.conf
Using interface wlan0 with hwaddr f8:d1:11:bd:62:ce and ssid "OpenWrt1"
Configuration file: /var/run/hostapd-phy1.conf
Using interface wlan1 with hwaddr 00:e0:4c:81:88:8a and ssid "OpenWrt2"