Frequently Asked Questions about CE and FCC Regulatory Certification for Wireless Wi-Fi Products

Wi-Fi products are now widely used in households. Is there anything special that needs to be paid attention to during regulatory certification (CE, FCC, MIC, etc.)? What is Wi-Fi 6? Is there any difference in the regulatory certification of such products compared with the past? Next, we will answer these common technical questions in the regulatory certification of Wi-Fi products one by one!

1. What do the commonly used Wi-Fi Channel and Band mean?

Answer: Channel refers to the channel where Wi-Fi works, and Band refers to the frequency band where Wi-Fi works.

Currently, the commonly used Wi-Fi mainly works in the two frequency bands of 2.4G (2400 - 2483.5MHz) and 5G (5G contains four sub-bands, B1: 5150 - 5250M, B2: 5250 - 5350MHz, B3: 5470 - 5725MHz, B4: 5725 - 5850MHz). The commonly said dual-band Wi-Fi refers to Wi-Fi products that support both frequency bands at the same time. Among them, the 2.4G frequency band is divided into 13 channels from CH1 to CH13, and the interval between each channel is 5MHz. The 5G frequency band is divided into several channels at an interval of 20MHz. The specific corresponding list is as follows:

2. What do the DFS test and DFS band mean?

Answer: DFS (Dynamic Frequency Selection) means dynamic frequency selection.

Currently, 5G bands (mainly B2 and B3 bands, also known as DFS bands) in many countries/regions around the world are used for various radar systems. Therefore, although 5G bands are open to Wi-Fi in these countries/regions, to avoid interference with radar systems when these Wi-Fi products detect radar signals in their DFS bands, they need to transfer their working channels in time and reselect new channels without radar signals or non-DFS bands to work. This is the DFS mechanism. DFS mainly includes two types: channel availability detection (CAC) during channel initialization and radar wave monitoring during operation. The tests in the regulations are also carried out for these two states. The following figure is a timing diagram of radar wave monitoring during operation:

3. How to distinguish between Master and Slave devices in DFS?

Answer: The master device refers to the device that is responsible for initializing the communication network during the communication process and can transmit signals without receiving additional control signals during the communication process. The most common one is a wireless router. The Slave device refers to the device that is controlled during the communication process. It must receive permission from the Master device before it can transmit signals, and when the Master device sends a channel transfer signal, it must transfer with the Master device.

The above two definitions apply to almost all communication systems, but the reason why they are emphasized in the DFS test is that the DFS test requirements of these two types of devices are very different. The Master device must meet all the requirements of the DFS test, while the Slave device can meet the requirements as long as it can fully obey the instructions of the Master device, complete the channel shutdown and transfer actions, and ensure that the channel occupied by the radar is no longer used within 30 minutes.

Note: Slave devices are also divided into two types: with radar wave detection and without radar wave detection. The Slave mentioned here refers to the device without radar wave detection. Slave devices with radar wave detection have the same requirements as Master devices except that there is no requirement for channel availability detection.

4. The available frequency range of 2.4G in the United States is also 2400 - 2483.5MHz. Why does common Wi-Fi only use CH1 - CH11 instead of CH1 - CH13?

Answer: From the perspective of the available frequency range alone, the United States can also use all channels from CH1 to CH13.

However, due to the requirements of the FCC Part 15.205 restricted frequency band (2483.5 - 2500MHz is the restricted frequency band, and it is close to the 2.4G available frequency band), based on the conventional transmission power of Wi-Fi products (about 16dBm), if the product does not perform special filtering for the restricted frequency band, CH12 and CH13 cannot meet the requirements of Part 15.205, which will cause this test to fail. Therefore, most products directly shield the two channels of CH12 and CH13 during design.

Of course, there are some products in the North American market that make CH12 and CH13 meet the requirements of Part 15.205 by significantly reducing the power of CH12 and CH13 or adding additional filtering circuits, but the market share of such products is currently small, and the vast majority of products still only use CH1 - CH11 channels.

5. What is Wi-Fi 2.4G CH14? Do products exported to Japan have to use CH14?

Answer: The centre frequency of CH14 is 2484MHz, which is a prohibited frequency band in most countries, except Japan.

CH14 is only allowed to be used in 802.11b mode. This channel is allowed in Japan, but Wi-Fi is not forced to use this channel, so it is also in compliance with the requirements for the product to shield this channel. At the same time, because CH14 and CH1 - CH13 belong to different laws and regulations, CH14 will have a separate certificate.

6. What are the available frequency bands for Wi-Fi 5G in Japan?

Answer: The available frequency bands in Japan are B1, B2, and B3. Wi-Fi B4 is prohibited in Japan.

B1 and B2 are limited to indoor use (when the product uses these two frequency bands, it is also necessary to indicate on the product label that the product is limited to indoor use). Therefore, if the Master equipment exported to Japan is to be used outdoors, the 5G frequency band can only use B3, and it needs to meet the DFS requirements.

7. Why do products exported to Europe that use 5G B1 and B2 need to reflect restricted use information on the product packaging?

Answer: According to the requirements of Article 10.10 of the RED Directive (2014/53/EU), when a product uses a technology or frequency band that is restricted in some EU countries, it is necessary to reflect on the product packaging which EU countries the product is restricted in.

According to the European Commission's resolution 2000/299/EC, radio frequency products are divided into two categories: Class I equipment and Class II equipment. Class I equipment has no restrictions on use in all EU member states; and except for a few specific restricted types of equipment, other Class II equipment is prohibited from use in EU member states. 5G B1 and B2 belong to Class II equipment, which is restricted to indoor use. Although they can be used in EU member states, they need to reflect restricted use information similar to the upper right picture on the product packaging.

8. For products such as air conditioners or smart sockets, if Wi-Fi is only used for reception, can the adaptive test be exempted?

A: For Wi-Fi 2.4G, only when the product's EIRP is less than 10dBm does it not need to test the adaptive function, and it must be tested in other cases; for Wi-Fi 5G, all products must meet the adaptive requirements, and there is no exemption clause.

9. What is Wi-Fi 6?

Answer: Since October 2018, the Wi-Fi Alliance has abandoned the Wi-Fi specification naming method that has been used since the 802.11a era, and named the next-generation Wi-Fi specification 802.11ax as Wi-Fi 6. At the same time, the existing 802.11ac was renamed Wi-Fi 5, and 802.11n was renamed Wi-Fi 4.

10. Are the certification requirements for Wi-Fi 6 different from other specifications?

A: Although Wi-Fi 6 has added many new technologies, such as narrower subcarrier spacing and new resource unit concepts, OFDMA, uplink and downlink MU-MIMO, BSS coloring, dynamic CCA thresholds, etc., from the perspective of current regulatory certification (excluding Wi-Fi Alliance certification), there are no special requirements for Wi-Fi 6 except for a significant increase in the amount of testing.