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15 #2: BAW filtering can help engineers provide seamless transitioning between interfering bands As shown in the following figure, the bandedge response is better using a filter than without it, and it allows designers to push the limit on RF front-end output power while meeting the FCC requirement for power spectral density. This means bandedge BAW filtering allows operators and manufacturers to deliver high-speed data and greater bandwidth by using spectrum that might be lost with no filtering. #3: High-Q BAW bandedge filters can extend the range in channel 1 and 11 by 2-3 times Wi-Fi designers normally must set the entire unit power to whatever the lowest bandedge-compliant power is for all channels. So, if the compliant channel at channel 1 is 15dBm but channel 6 can achieve 23dBm, the designer settles the entire power control scheme to 15dBm. Using bandedge filtering allows designers to set the power scheme to much higher powers, thus making it possible to use fewer RF chains to achieve their goals. BAW bandedge filters can also exhibit power handling capabilities for transmitting up to 28dBm. This can improve system performance by greater than 15 percent and enable 5G multi-MIMO with less co-channel interference. Customer premises equipment (CPE) developers who don't use bandedge filtering have difficulty meeting FCC requirements on Wi-Fi band channels 1 and 11. In contrast, when high-Q BAW bandedge filters are used, it allows the CPE designer to keep the power level the same throughout all the channels (1 – 11). To paint the picture, here's the difference in user experience with and without bandedge filters: Without bandedge filters: Let's assume you're in a house with several individuals using Wi-Fi and mobile phones. You're on Wi- Fi using channel 5, streaming a football game and experiencing no buffering or interruption. But then new mobile users arrive in the house and begin to take over your channel 5 Wi-Fi space. The CPE unit adjusts and bounces you to channel 1 to free up more space on channel 5. If the Wi-Fi unit doesn't have bandedge filters (as in the block diagram on the left), your Wi-Fi strength and streaming degrade to the point where buffering occurs. Why? Because to meet the FCC requirement, the CPE unit must back off its power in channel 1 so it doesn't interfere with adjacent cellular bands. With bandedge filters: However, if the CPE unit had been designed with bandedge filters (as shown in the block diagram on the right), channel 1 and 11 would not be compromised and the power level would not require backoff. You can watch your streamed football game without any buffering. Go In Depth: How Qorvo Wi-Fi Solutions Can Help Solve Interference Challenges In a connected world with more and more devices and wireless standards, coexistence and interference issues will not go away. To make use of every bit of spectrum available, Wi-Fi designs with high-Q BAW filters can improve the performance of Wi-Fi access points. ©2018 Qorvo, Inc. FCC Restricted Bandedge With and Without BAW Filter 100mWatt Ch1 Ch2-10 Ch11 Ch1 Ch2-10 Ch11 100mWatt MIMO MIMO Wi-Fi 1Watt 1Watt 1Watt 1Watt Wi-Fi Wi-Fi Wi-Fi ©2018 Qorvo, Inc. Wi-Fi/LTE System Models (With/Without Bandedge Filters)

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