GUEST BLOG: Throughput? Nah… This time, Wi-Fi 8 is all about ultra high reliability

Guest blog by Khushboo Kalyani, Product Marketing Manager, LitePoint

LitePoint is a world leader in test solutions for Wi-Fi and in this guest blog, Product Marketing Manager Khushboo Kalyani explores the future world of Wi-Fi 8, the next Wi-Fi standard. What can we expect from Wi-Fi 8? There are plenty of transformational new features in the pipeline, she says.

Humans have always sought connection, and technology has made that possible. For decades, the goal of wireless technology has been to provide basic connectivity and extend it globally, empowering everyone with access to the internet. The vision was to blanket the world with this capability.

In developed economies, this progression was fast, pushing the evolution of wireless technologies from offering basic connectivity to supporting higher data rates, and eventually managing greater user densities. Whenever we ran out of spectrum, we resorted to either adding more spectrum or developed techniques to use it more efficiently. After 24 years of widespread Wi-Fi adoption, the question arises: What more can Wi-Fi offer?

As it turns out, there’s much more on the horizon. With AI use cases flooding the market, we now require communication systems that are highly reliable and offer lower latency. This is critical for real-time data processing and near instantaneous decision-making in industries like healthcare and security.

In our march towards an immersive and digital world these qualities are even more significant, as lag between our physical and augmented and virtual reality environments can lead to discomfort or even motion sickness.

As a typical consumer, you might think your needs of streaming or uploading YouTube videos are being met. However, the IEEE standards body has a forward-looking vision, recognising how the industrial applications and infrastructure around us are evolving and what support they need from the next wave of technology. But wait—doesn’t Wi-Fi 8 promise faster speeds? What exactly does it bring to the table?

Well, we are still pre-spec and expect the first draft of the IEEE 802.11bn standard aka Wi-Fi 8 to be finalised in Q1 2025, but we’re already starting to see some exciting features emerging!

Feature possibilities

The IEEE standard made significant strides with features added in Wi-Fi 7 and the addition of 6 GHz band in Wi-Fi 6E. The two generations open a wealth of possibilities, offering features which enable deployment flexibility across different geographic regions and a wide array of devices, from low power long range IoT devices to high throughput access points.

So, what more can we expect from Wi-Fi 8? Based on the publicly available IEEE documents, it appears there won’t be any new spectrum additions or bandwidth expansions beyond 320 MHz. Therefore, it’s important to approach Wi-Fi 8 as an incremental upgrade, focused on enhancing current implementations and improving overall reliability.

What can we expect?

1 – Improved Channel Utilisation and Reliability

For backward compatibility with legacy client devices which operate only on 20 MHz channel, Wi-Fi introduced the concept of primary channels in 802.11n (Wi-Fi 4). While this approach is accommodating, the restriction to 20 MHz channel even when the device has access to wider operational bandwidth renders other channel subsets idle, particularly in congested environments.

With Wi-Fi 8, we may see a resolution to this with the use of non-primary channel access or dynamically switching to secondary channels. This approach may help reduce transmission delays and increase the likelihood of successful transmissions. Beyond optimizing throughput, it will enhance spectrum efficiency, reduce overhead and lower latency without adding extra complexity.

You might be wondering how this differs from Multi-Link Operation (MLO). The key distinction is that MLO allows for the aggregation of separate channel blocks within the same or different bands, while non-primary channel access enables the use of secondary channels within the same channel block when the primary channel is busy.

2 – Improved Link Adaptation and Transmission Efficiency

Moving to higher-order modulation schemes has historically been an established way to increase throughput in new Wi-Fi generations. Wi-Fi 7 introduced 4096 Quadrature Amplitude Modulation (QAM), allowing 12bits/symbol to be tightly packed.

However, advancing further to 8192-QAM or greater adds practical limitations due to diminishing returns in throughput relative to the required investment. The denser the modulation, the higher the signal-to-noise ratio required to minimize errors, and would only operate at relatively short ranges.

Additionally, it necessitates complex and costly circuit components to maintain signal integrity for a fractional gain in throughput, thus making it impractical to pursue modulation rates beyond 4096-QAM. This is why the Wi-Fi 8 task group is looking to introduce new coding rates for existing modulation schemes like 256 QAM/ 16QAM/ QPSK to increase the robustness of data transmission and improve reliability. Thus, increasing the odds of successful transmission even in noisy environments or under poor SNR conditions.

3 – Range Extension with Distributed Resource Units (dRU)

Specifically designed for low-power indoor (LPI) devices in the 6 GHz band, dRU allows for the distribution of allocated tones across a wider bandwidth, reducing the number of tones per MHz. This boosts uplink OFDMA transmission power, effectively extending transmission range and improving overall performance for these devices.

4 – Power Saving and Reduced Latency for Periodic Traffic

Originally planned for 802.11be standard, the restricted target wake time (TWT) could make it into the first draft of 802.11bn standard. The feature allows devices to negotiate specific times for transmission of latency-sensitive traffic with access points. This will not only enable power saving for IoT devices but also minimise the likelihood of contention with non-latency sensitive traffic, reducing latency as well as improving predictability of transmission.

5 – Improved Co-existence and Network Efficiency with Aggregated PPDU

The standard body is looking at several ways to improve efficiency and this one is particularly interesting as it intends to allow client devices to aggregate and transmit multiple types of PHY packets within a single physical protocol data unit (PPDU). This will improve network efficiency by avoiding the need for separate transmissions, although it may just be limited to aggregation of Wi-Fi 6, 7 and 8 packets.

6 – Minimised Contention and Reduced Latency with Multi-AP Coordination

Another feature that was originally planned for Wi-Fi 7 is now being reconsidered for Wi-Fi 8. Previous generations of Wi-Fi primarily focused on enhancing single-AP performance, with features like MU-MIMO, UL OFDMA, and multi-RU to improve multi-user efficiency in high-density environments.

However, they lacked AP-to-AP coordination mechanisms for effective resource sharing and optimized coverage. Multi-AP coordination is an effective PHY and MAC layer mechanism that will optimise transmissions in both dense and weak signal areas. It will enable access points (APs) to coordinate their frequency, time, and power resources to better serve client stations and manage network resources.

APs can implement this coordination in a few ways: they may take turns transmitting on the same channel during a transmit opportunity (TXOP) or transmit simultaneously on non-overlapping channels to minimise interference. A critical element for successful implementation is the use of beamforming techniques, which can enhance focused coverage and further reduce interference. This coordinated approach will also decrease retransmissions and minimise overall latency.

7 – Integration with AI and Machine Learning

It is essential for Wi-Fi to explore the endless possibilities of AI and leverage it to drive enhancements and improve connectivity. The IEEE is closely looking into ways to leverage AI and ML to improve network efficiency and user experience. The implementation may be centered around predictive channel modeling, traffic patterns and device behaviours to proactively manage resources. Particularly for real time latency sensitive traffic, this approach will bring a certain level of determinism, guaranteed quality of service and promised latency critical necessary for immersive reality applications, online gaming and more.

A holistic & integrated approach with Wi-Fi 8

The features discussed above are not exhaustive. We are still a couple of months away from the first draft of 802.11bn spec and the IEEE body is considering many additional enhancements. Nonetheless, the intent of the article was to bring out the fact that unlike previous generations, which focuses primarily on prominent physical layer implementations like wider bandwidth and denser modulation schemes, Wi-Fi 8 is focusing on a more holistic and integrated approach.

This generation is looking to implement features that require enhancements at both the PHY and MAC layers. It emphasises metrics that may be challenging to quantify but will have a significant impact on latency and determinism to support advanced applications like holographic telepresence, ultra-HD streaming, autonomous vehicles and more.

The renewed outlook of Wi-Fi 8 standard marks a significant shift in the technology development with singular focus on reliability, setting the stage for a new era of connectivity that will empower the most demanding applications of tomorrow.

/Khushboo