Issue link: https://resources.mouser.com/i/1207833
21 In a previous article, we covered five key things to know about 802.11ax, the next big standard for Wi-Fi. Let's examine some of the challenges that radio frequency (RF) engineers will face when designing for 802.11ax and some tips on how to overcome them. Some Background: 5 OFDMA PPDU Formats for 802.11ax But first, let's look at the foundational signal structure for 802.11ax—the physical layer protocol data units that Wi-Fi clients and devices use to communicate. 802.11ax uses five formats for its OFDMA PPDU: • Single User (HE-SU). For transmitting data from a single user. • Multi User (HE-MU). For transmitting data to one or more users that isn't in response to a trigger frame. • Outdoor (HE-xSU). For outdoor transmission for a single user. This format is new in 802.11ax. • Trigger Response (HE-TRIG). For transmitting data in response to a trigger frame. Used to coordinate uplink MU- MIMO or uplink OFDMA transmissions with the access point. • Downlink Channel Sounding (HE-NDP). For beamforming and downlink channel sounding. See the image at the end of this article for details of the frame packets and fields within each PPDU format. Designing for 802.11ax Wi-Fi: Common Challenges and Tips to Overcome Them Glossary of Terms: Evm: Error Vector Magnitude He: High Efficiency Hew: High-Efficiency Wlan (Or High-Efficiency Wireless) Mu-Mimo: Multi-User Multiple Input/Multiple Output Npd: Null Data Packet Ofdma: Orthogonal Frequency-Division Multiple Access Plcp: Physical Layer Convergence Procedure Ppdu: Plcp Protocol Data Unit Qam: Quadrature Amplitude Modulation Twt: Target Wait Time By Jeff Jones, Qorvo Senior Manager, Applications Engineering