Qorvo Cees Links

Cees Links is a Wi-Fi pioneer and the founder and CEO of Greenpeak Technologies and currently General Manager of Qorvo’s Wireless Connectivity business unit.

17 June 2020

Wi-Fi 6, also known as 802.11ax, is the next-generation standard in Wi-Fi technology. What’s exciting about it is that it expands on 802.11n (Wi-Fi 4) and 802.11ac (Wi-Fi 5) by improving data capacity, the number of connected user devices per node and throughput over the full RF range. Wi-Fi 6 offers theoretical speeds of up to 10 Gb/s. The new standard also implements orthogonal frequency division multiple access (OFDMA), which runs in full-duplex (up and downstream), multi-user, multiple-input-multiple-output (MU-MIMO). It supports twelve streams, allowing each stream to service multiple devices.

Under the Wi-Fi Alliance’s certification program, designs can be submitted for certification. This is driving both indoor and outdoor Wi-Fi 6 manufacturers to certify and deploy infrastructure with certified units. These manufacturers, then, need a vendor with both an indoor and outdoor Wi-Fi 6 portfolio covering front-end solutions plus filtering – preferably in the context of a large portfolio that also includes multi-protocol solutions focusing on Wi-Fi/IoT coexistence. To benefit from the improved capabilities, there’s also a need for devices with higher levels of linearity, interference mitigation and lower power consumption – all in a smaller form factor. Wi-Fi 6 manufacturers require the RF front-end devices to achieve these parameters in order to meet certification program demands.

With the rise in data throughput (four times greater than Wi-Fi 5) and the larger number of users per node (four times the Wi-Fi 5 capacity), the RF design portion of a Wi-Fi end-product has increased in complexity. Not only has the modulation scheme increased to 1024 QAM, quadrupling wireless speeds compared to Wi-Fi 5, but receiver sensitivity and power amplifier linearity have become more challenging.

The increase in QAM means more challenging RF linearity requirements – as high as -47 dBm error vector magnitude (EVM) for some manufacturers. To address this, optimized RF front-end (RFFE) devices can be used having EVM margin to ensure end-product certification. The increased sensitivity specifications mean a lower noise figure (NF) in the receive path is a must-have. With both 5G and Wi-Fi 6 standards demanding lower power consumption targets, the added challenge is to meet the above specs while keeping end-product power consumption at a minimum. Furthermore, new coexistence challenges in 2.4 and 5 GHz bands increase the need for specialized filtering.

EVM and noise are key parameters to focus on in a Wi-Fi 6 product or application. EVM is a measure used to quantify the performance of a digital radio transmitter or receiver. Noise (including phase noise), distortion and spurious signals can degrade EVM. Because real-world Wi-Fi applications are pulsed (the PA pulses on each time it transmits data, then pulses off to save power), design engineers should focus their attention on dynamic EVM values on product datasheets, as these values accurately reflect how a PA in a Wi-Fi system operates. Thus, choosing components with dynamic EVM levels measured in pulse modes are the best choice.

Another recommendation is to choose a product that covers 2.4 and 5 GHz. These products include embedded filter solutions to address band edge and coexistence. The overall benefit of band edge filters is RF range and quality of service without interference from Bluetooth, microwave ovens, cellular phones and such. There are also products that address the emerging expansion of Wi-Fi 6 in the 6 GHz space (also called Wi-Fi 6E).

Lastly, it’s important to note the trend to integrate Wi-Fi and IoT (ie Zigbee, Thread and BLE). The smart home space is seeing this merger into one package design or home network – bringing together the smart home, the internet, lighting control, voice activation control, home automation and security. Products that offer these two technologies in one solution, reducing customer complexity and design, represent an advantage in getting to market faster and with confidence.

Wi-Fi 6 is up and running, offering distinct advantages over its predecessors. Designers who are savvy enough to optimize their application designs for Wi-Fi 6 will have the competitive edge by unlocking the full potential of this new standard.