Introduction

           DFS is Dynamic Frequency Selection, which is a function of using 5 GHz Wi-Fi frequencies that are generally reserved for radar, such as military radar, satellite communication, and weather radar. The DFS channels vary from country to country. The main benefit to use DFS channels is to increase the number of Wi-Fi channels. It is legally required Channel Availability Check process to prevent electromagnetic interference the 5 GHz frequency with the radar. If any radar signal detects, it will switch from DFS channel to non-DFS channel automatically(If driver have DFS support) .

Scope

          The scope of this work is to integrate the DFS Feature in RPI reference platforms.This document covers only integration not validation.

Target Audience  

• RDK-B Operators
• RDK-B SoC Vendors
• RDK-B OEM's
• RDK-B Application Vendors
• RDK-B System Integrators 

Supported device  

• Raspberry Pi4 32 bit
• Raspberry Pi4 64 bit

Supported dongle

• Tp-link AC1300 WiFi 5 Archer T4U 
• Amazon link to purchase : https://www.amazon.in/TP-Link-Archer-T4U-Wireless-Adaptor/dp/B01N2U8YRF?th=1

Build Instructions

High Level Design

TR-181 Data Model Parameters

Test Procedure and Test Results

        1. Enabling the DFS feature in RPI Router. By default, it's disabled.

       2. Getting the current 5G Radio channel

       3. Connected Client info

          4.Changing the 5G channel value from non-dfs to dfs frequency

          5. Re-enable the AP/Radio to update the new channel value in realtek driver

         6. Connected client info with DFS frequency

            Tested Image :

root@RaspberryPi-Gateway:/# cat version.txt 
imagename:rdkb-generic-broadband-image_rdk-next_20240605110458
BRANCH=rdk-next
YOCTO_VERSION=kirkstone
VERSION=5.06.05.24
SPIN=0
BUILD_TIME="2024-06-05 11:04:58"
Generated on Wed Jun 05  11:04:58 UTC 2024
root@RaspberryPi-Gateway:/# 

Feature Validation

                    TBD - We didn't validate with RADAR signals  .

Limitations

               This rtl88x2bu driver doesn't have the channel switch support. So, we need to do the re-enable of AP/Radio whenever we switching the new channel .

References

REFPLTB-2925 - Getting issue details... STATUS