While Wi-Fi 6/6E represented a paradigm shift with associated testing requirements, Wi-Fi 7 promises to refine and expand Wi-Fi 6 functionality. This underscores the importance of now having a smart testing strategy to ensure smooth evolution. More information about Wi-Fi 7 developments.
Each generation of Wi-Fi has offered higher data transmission speeds with the goal of improving performance for end users. It’s an increasingly difficult task: think of an average family surrounded by devices competing for the same waves. Or the same scenario faced by an enterprise user.
Wi-Fi 6 aimed to resolve this dynamic at home and in the office. It was a paradigm shift that introduced new features and mechanisms to better support multiple users. On the heels of Wi-Fi 6 came Wi-Fi 6E, which incorporated the use of the 6 GHz spectrum.
Looking ahead to what comes next, the industry has its sights on Wi-Fi 7, which promises to refine and expand Wi-Fi 6 functionality in the 6 GHz spectrum. It adds new features and mechanisms designed to finally solve problems that have persistently hindered certain Wi-Fi use cases.
While the main advantage of Wi-Fi 7 is higher throughput (up to 12 Gbps), it does not come easily.
Let’s see why and what implications it has, starting with Wi-Fi 7’s main features and advantages.
320 MHz Bandwidth for Much More Data
Like Wi-Fi 6E, Wi-Fi 7 uses the 6 GHz spectrum, which supports channels up to 320 MHz, twice that of Wi-Fi 6E and four times that of Wi-Fi 6. In fact, with Wi-Fi 7, the bandwidth is much larger. Three 320 MHz channels can be obtained in the 6 GHz band. As a wider channel can transmit more data, the Wi-Fi 7 pipe is larger than ever.But is that spectrum really usable? In such a wide 320 MHz channel there is likely to be some interference in the band, meaning some sections of the channel could become unusable. Wi-Fi 7 solves this problem by using a mechanism to puncture that part of the spectrum so it is divided, but the rest of the 320 MHz channel can be used.
Higher-Order Modulation for 20% More Speed
Quadrature Amplitude Modulation (QAM) transmits data over radio waves using discrete points on the constellation diagram. Each discrete point represents a number of data bits. The more discrete points allowed, the more data can be transmitted. Wi-Fi 6 offers 1024 (point) QAM, which is a 25% increase in data transmission rate compared to Wi-Fi 5. Wi-Fi 7 has increased it another 20% to 4096 QAM, which is 12 data bits per symbol.The problem with this high-order modulation is the impact of channel noise, which makes demodulation difficult. Although 4096 QAM is fast, it needs a high signal-to-noise ratio (SNR) to work properly. This limits its use to short operating distances, around 18 feet, lower for some applications but excellent for others, such as virtual reality.
Multiple Resource Units Improve Spectrum Efficiency
OFDMA improves performance by allowing simultaneous transmissions between multiple clients. With Wi-Fi 6 and LTE, a channel can be divided into Resource Units (RU), which are frequency groupings. Each device is assigned an RU. To improve spectrum efficiency, Wi-Fi 7 allows multiple RUs to be assigned to each device, thus taking advantage of spectrum that might otherwise remain unused.Multi-Link Operation Increases Link and Channel Efficiency
In traditional Wi-Fi mesh networks, each mesh node communicates with nearby devices on a single band and mesh nodes communicate with each other. Sometimes this approach is not efficient for inter-device traffic. Instead, with Wi-Fi 7, multi-link operation (MLO) allows multiple simultaneous links to operate on separate channels, with each link operating independently. For example, 2.4 GHz, 5 GHz, and 6 GHz radios can be used as if they were one.MLO is an important Wi-Fi 7 innovation. It is a unified and coherent framework for managing multiple links consistently, reducing management overhead. By aggregating links on different channels, MLO increases throughput. It also improves latency by using multiple links in parallel for flexible channel access. Reliability can be increased by sending duplicate data over multiple links, and quality of service (QoS) can be improved by routing traffic to appropriate links.
Improved Quality of Service Management for Priority Access
Normally, all devices compete for the same channel on a first-come, first-served basis. This is not viable for applications like voice calls, where timing is critical.Wi-Fi 7 introduced improved quality of service management so devices can request guaranteed time. For example, they could inform the access point that a voice call will need 5 ms every 20 ms. The access point will pre-allocate the channel if possible. This guarantees channel access when the voice packet is transmitted. Improved QoS management provides smoother channel access management than previous first-come, first-served methods.
Restricted Service Periods for Deterministic Latency
Latency is important for improving reality. Wi-Fi 6 improved latency with OFDMA but, depending on the number of players in the house, latency could fluctuate significantly. Wi-Fi 7 can provide deterministic latency that reserves what you need when you need it.Wi-Fi 7 Testing Considerations
The new features of Wi-Fi 6 had significant testing implications that need to be refined for Wi-Fi 7. The biggest impact is multi-link operation, which will require new testing methodology and test plans due to greater coherence, but a different approach compared to standard mesh device testing. Similarly, testing methodologies for QoS latency will need to be improved.As always, test planning will leverage Wi-Fi Alliance test plans when available. In the meantime, maintaining an up-to-date testing approach for Wi-Fi 6 and Wi-Fi 6E is essential to keep pace with Wi-Fi technology evolution.
Wi-Fi Testing with Octobox: https://www.tecnous.com/wp-content/uploads/2022/08/Datasheet_octoBox.pdf
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