February 12, 2017

DFS Transmitter Testing

CKC Laboratories is now providing Dynamic Frequency Selection (DFS) testing to meet the requirements for USA (Part 15.407 & 15.247), Canada (RSS-247, European Union (EN 301 893) and Australia (EN 301 893). Typical products falling under DFS requirements are those using the UNII 2 bands of 5.25-5.35 and 5.47-5.725 GHz, including wireless radio networks such as Wi-Fi 802.11a, 802.11n, or 802.11ac. These radios are utilized in access points, cell phones, computers, etc. for local area networks and are typically deployed by Internet Service Providers.

The purpose of DFS testing is to ensure coexistence of these radio networks with military and commercial radar devices utilizing the same spectrum. These radar devices may include aviation safety (weather radar) or military applications (missile detection). Obviously, interference with these systems could pose a severe threat to public safety. Radios are required to detect the radar signals and take appropriate action (e.g. stop transmitting, change channel, etc.). Hence the name “Dynamic Frequency Selection.” When a radar signal is detected, the radio dynamically reallocates the used spectrum to avoid interference with incumbent systems.

There are several important requirements found within DFS testing. These include:

• Channel availability check time (CAC)
• Channel move time
• Channel closing time
• Non-occupancy time
• Interference detection threshold

It is important to note that the detection threshold is tested for a variety of different radar patterns which do vary from region to region. Also, testing is performed using the LOWEST gain of each type of antenna.