How Designers Achieve Tri-Band Gigabit Speeds and High Throughput in Wi-Fi

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How Designers Achieve Tri-Band Gigabit Speeds and High Throughput in Wi-Fi [Copy link]

Engineers are constantly looking for the simplest solution to complex system design challenges. Consider the U-NII 1-8, 5, and 6 GHz solutions. In this article, we will review how best-in-class bandBoost filters can increase system design capacity and throughput, providing engineers with a simple and flexible solution to implement complex designs while helping to meet stringent end-product compliance requirements.

Overview of Current Wi-Fi Development

Wi-Fi usage has grown exponentially in recent years. Most recently, the pandemic of 2020 has driven Wi-Fi usage to unimaginable levels due to work-from-home, school requirements, gaming advancements, and 5G developments. According to Statista, home data usage increased 18% in the first week of March 2020 compared to the same period in 2019, with daily average data usage exceeding 16.6 GB.

As usage increases, so does the expectation to be able to use Wi-Fi anywhere, at home, outside, and at work, as wireless technology continues to advance. Meeting these expectations requires more wireless backhaul equipment to transmit data between the Internet and the subnets. It also requires leveraging existing technology advances to meet the growing demands for capacity, range, signal reliability, and the number of new applications offered by wireless service providers. Figure 1 Applications—from email to video conferencing, smart home features, gaming, and virtual reality—are growing exponentially.

Figure 1: The evolution of Wi-Fi

The 802.11 standard has now evolved to Wi-Fi 6 and Wi-Fi 6E, providing services in the 5 GHz and 6 GHz frequency band ranges (up to 7125 GHz), as shown in Figure 2. This higher frequency range increases the video capacity for our security systems and streaming media.

Figure 2: Tri-band Wi-Fi frequency bands

However, operating in higher frequency ranges can introduce additional challenges, such as more signal attenuation and increased heat, especially when trying to meet small form factor requirements. To meet these challenges, RF front-end (RFFE) engineers need to take existing technologies to a whole new level. One such advancement is BAW filtering technology, which is now beginning to be widely used in Wi-Fi system designs.

As shown in Figure 3 below, Qorvo has three BAW filter models that can improve overall Wi-Fi performance, maximize network capacity, extend RF range, and reduce interference between the many different home radios operating simultaneously.

Figure 3: BandBoost, edgeBoost and coexBoost filter technology performance

5 GHz and 6 GHz bandBoost filters

In a previous blog post titled “5.2 GHz RF Filters, a Critical Part of Wi-Fi Tri-Band Systems”, we discussed how bandBoost filters, such as the Qorvo QPQ1903 and QPQ1904, can be used to reduce design complexity and enable coexistence. We also explored how these bandBoost filters can achieve higher isolation, thereby reducing this function in the antenna design, thereby reducing antenna cost. As a result, the RFFE isolation parameter is no longer completely dependent on the antenna. This can reduce the cost of the antenna and shielding by up to 20%.

These bandBoost BAW filters play a key role in differentiating the U-NII-2A band from the U-NII-2C band, with only a 120 MHz band gap between the two bands, as shown in Figure 4. Using these filters, we can enable Wi-Fi coverage to every corner of the home with the highest throughput and capacity. By using this solution in Wi-Fi system design, the end user capacity is increased by 4 times.

Figure 4: 5 GHz and 6 GHz bandBoost filters and U-NII 1-4 bands

These filters are significantly smaller than traditional filters used in Wi-Fi applications on the market, enabling more compact tri-band radio solutions. They also offer excellent isolation performance, allowing designers to achieve system isolation performance exceeding 80 dBm. This helps engineers meet demanding Wi-Fi 6 and 6E requirements.

Figure 5: Benefits of using QPQ1903 and QPQ1904 bandBoost filters

Adding multiple-input, multiple-output (MIMO) and higher frequencies in the 6 GHz range increases system temperatures. As thermal requirements increase, reliable RFFE components must be used. Many manufacturers in the industry have parts rated for operation in the 60°C to 80°C temperature range, but the operating temperature is often higher due to the system temperatures generated in this frequency range. To address these design challenges, we have spent a lot of time improving BAW temperature performance. As product designs are based on Wi-Fi 5, 6/6E and the upcoming Wi-Fi 7, development work is more challenging, and as BAW opens new markets such as the automotive field, the need for higher temperature performance has become a priority.

Qorvo BAW technology engineers have designed innovative devices with a maximum operating temperature of over 85°C (up to +95°C). This is a great benefit to both product designers and end product customers. End products now no longer require large heat sinks, allowing for sleeker devices. At the same time, engineers can more easily meet system thermal requirements, reducing design time. Another thermal-related advancement is that bandBoost BAW products can operate at +95°C while still meeting the 0.5 to 1 dBm insertion loss requirement.

The reduction in insertion loss can improve Wi-Fi range and reception quality by 22%. Lower insertion loss means better thermal performance due to improved RF signal to the RFFE low noise amplifier (LNA). Figure 6 below shows the capabilities and benefits of the QPQ1903 and QPQ1904 edgeBoost BAW filters.

Figure 6: Features and benefits of QPQ1903 and QPQ1904

Not only do these filters provide the benefits of an LNA, but they are small, perform well, and can fit inside a tiny integrated Wi-Fi module package that includes the LNA, switch, PA, and filter. This can significantly change the system layout of the end product, simplifying product design and helping to reduce time to market. Instead of matching and inserting separate passive and active components on their PC boards, engineers can now do it all in a complex integrated module called an integrated front-end module (iFEM), creating a plug-and-play solution that can be easily installed in a design.

A classic example is the QPF7219 2.4 GHz iFEM, shown in Figure 7. Qorvo not only provides a discrete edgeBoost BAW filter solution to increase the output and capacity of all Wi-Fi channels, but also incorporates the filter into our iFEM (QPF7219), providing customers with a pin-compatible drop-in replacement with the same capacity and range performance. This provides customers with design flexibility, saves board space in their designs, and is the first device of its kind on the market.

Figure 7: edgeBoost used as a discrete component inside an iFEM

Smaller, sleeker product designs are often top of mind for Wi-Fi engineers. But to achieve this goal, component designers need to develop smaller products in many design areas, not just one or two. From a tri-band Wi-Fi chipset perspective, Qorvo has addressed this issue head-on. Qorvo offers a complete set of iFEM replacement products to meet the needs of many signal transmission and reception lines in a product. This enables Wi-Fi design manufacturers to manage all UNII and 2.4 GHz bands in a tri-band end product design.

Figure 8: 2.4 GHz and 5 GHz Wi-Fi 6 and IoT tri-band front-end solution

This new design solution uses the filter inside the iFEM, which is equivalent to shrinking the PC board and reducing shielding, as shown in Figure 9 below. The cost of shield matching and PC board space is very high, not to mention the additional time required to provide these materials. By placing all RFFE materials in one module, system designers can save costs, speed up design, and shorten their time to market.

Figure 9: Using filter technology in iFE eliminates shielding issues and reduces the overall size of the RFFE

As Wi-Fi system designers are constantly challenged by new regulatory requirements, they need updated or enhanced technologies to meet the needs. By working with our customers, we can provide best-in-class solutions to solve the tough problems faced by their end customers, such as thermal, performance, size, interference, capacity, throughput and range. With these solutions, our customers can improve their designs to meet the development needs of Wi-Fi today and in the future.