Wi-Fi ’s economic impact has reached $5T pa after 20+ years
Wi-Fi, based on IEEE 802.11, has developed over the last 20+ years to address the needs of an increasingly diverse set of use cases. Wi-Fi was originally focused on connecting a laptop to an access point, often in the executive suite of the enterprise. Today, Wi-Fi is everywhere: in homes, enterprises, factories and public spaces; carrying all sorts of traffic, from the humble e-mail all the way through to low latency, high throughput augmented and virtual reality applications. The impact and diversity of Wi-Fi is best summarized by the most recent economic study on the impact of Wi-Fi that forecasts Wi-Fi will contribute almost $5 trillion per annum to the global economy by 2025.
Wi-Fi ’s success is based on continuous improvement & development
Wi-Fi’s success has been based on a long series of amendments to the IEEE 802.11 standard, which was first approved in 1997. Key amendments have specified new PHY layer protocols and associated MAC layer refinements on a regular basis: 802.11b, 802.11a, 802.11g, 802.11n (now known as Wi‑Fi 4), 802.11ac (Wi-Fi 5) and most recently 802.11ax (Wi-Fi 6 & Wi-Fi 6E). Each of these amendments introduced new and exciting features to meet the expanding needs of existing and new market segments: higher throughput, lower latency, greater reliability, improved efficiency, and enhanced management.
Wi-Fi 7, the next generation of Wi-Fi, is focused on Extremely High Throughput
The IEEE 802.11 Working Group is continuing the tradition of the last 20+ years as it specifies the next generation of Wi-Fi, as IEEE 802.11be. This new amendment, which is expected to be marketed by the Wi-Fi Alliance as Wi-Fi 7, is labelled by the Working Group as Extremely High Throughput (EHT). The first release of IEEE 802.11be (the current plan is to define IEEE 802.11be in two releases) is likely to include a variety of features that have an obvious connection to high throughput, including definition of 320 MHz channels (in IEEE 802.11ax, 160 MHz was the maximum channel width) and 4096 QAM modulation (in IEEE 802.11ax, 1024 QAM was standardized). Using a car analogy, these features are equivalent to installing a bigger engine capable of propelling the car at scarily high speeds.
Some Wi-Fi 7 throughout improvements will derive from efficiency features
The first release of IEEE 802.11be is also likely to include a variety of other features that contribute to higher aggregate throughput by improving efficiency of access, such as Multi-Link Operation and Restricted Target Wake Time (TWT). These other features will also contribute to lower latency and greater reliability. Multi-Link Operation allows a client device to be connected to an access point using two or more radios simultaneously; for example, a 2.4 GHz radio, a 5 GHz radio or a 6 GHz radio. Restricted TWT enables an access point to allocate exclusive access to the medium at specified times, building on a feature that was first defined in IEEE 802.11ah (also known as Wi-Fi Halow) and subsequently incorporated into IEEE 802.11ax.
Extending the car analogy, Multi-Link Operation is akin to allowing cars to continuously and dynamically select the “best” lane on a highway rather than requiring them to stay in a single lane for long periods (actually it also allows cars to use multiple lanes at the same time … but cars don’t really do that), and Restricted TWT is akin to adding a dedicated lane for carpools (or paying drivers). Both features, if used appropriately, improve aggregate throughput by providing flexibility to optimize operations via a managed use of network resources.
Wi-Fi 7’s efficiency features are as important as the pure throughout features
Owning a car with a big engine is really important if you are gear-head (or rev-head in my part of the globe) … or a police officer chasing the gear-head for exceeding the speed limit. However, for most people, the big engine is actually less important than driving on a road built for safe driving. Even for the gear-head, the big engine is more important to show off, rather than anything else, because there are not that many opportunities to use it.
It is similar with Wi-Fi 7. Features like 320 MHz channels and 4096 QAM modulation are going to be really important for some use in specialized cases, and certainly they will be important for vendors and consumers more interested in a big (throughput) number on the box. However, features like Multi-Link Operation and Restricted TWT are likely to be just as important in many, if not most, practical use cases. This is particularly true in the enterprise and industrial/IOT use cases in which Cisco’s customers have a particular interest.
The efficiency features in Wi-Fi 7 need refinement to improve practicality
The problem is that, while Multi-Link Operation and Restricted TWT could be really useful features in the future for IEEE 802.11be, their current draft definitions require refinement to ensure that their promises are fulfilled in practice. The source of the problem is similar in both cases. Traditionally, Wi-Fi has relied on each client device to make many of its own big operational decisions, such as its operating channel, when to be awake, when to roam, its transmit power or aspects of its channel access mechanism. However, client devices often have a more limited perspective of the overall network and its goals than the network infrastructure, particularly a well-managed enterprise class network infrastructure like that offered by Cisco. These clients will benefit from active guidance and management from the network infrastructure. The best way to go to achieve the next level of Wi-Fi performance, which is the goal of Wi-Fi 7, is to trust and leverage the network infrastructure perspective.
All Wi-Fi 7 clients should respect Restricted TWT rules
In the case of Restricted TWT, the current definition in the draft version of IEEE 802.11be allows client devices to ignore attempts by the network infrastructure to allocate exclusive access to a particular channel at specified times. This essentially makes the Restricted TWT feature almost useless in practice, in the absence of the use of relatively disruptive management mechanisms by the network infrastructure to move these clients off the channel. Refinements are required in the draft version of IEEE 802.11be to allow the network infrastructure to more easily manage the network so that Restricted TWT can operate in a channel without disruption by devices (including legacy devices) that do not understand or respect the Restricted TWT mechanisms. The fundamental request is that individual clients defer to the interests of the wider community of clients and respect the ability of the network infrastructure to manage access efficiently and effectively.
Wi-Fi 7 should enable network infrastructure management of Multi-Link Operation
In the case of Multi-Link Operation, the current definition in the draft version of IEEE 802.11be allows client devices to use the multiple links as they choose. However, the clients do not have a view of the overall network or its goals sufficient to optimize operations. For example, performance optimization requires that the infrastructure has the ability to add and delete links dynamically, as it undertakes necessary operations like channel availability checks for radar avoidance or interference reduction. It also requires an understanding of how to distribute traffic across the multiple links in a way that achieves the overall goals of the network, and not just the individual client. This is especially true during times of spectrum scarcity or in relation to protecting critical site operations.
Wi-Fi 7 needs network infrastructure-based management tools to support enterprise/industrial use cases
In many typical enterprise or industrial environments, it will be desirable, or even vital, for the network infrastructure to manage and optimize network operations in order to achieve network-wide goals. For example, in a healthcare environment, network infrastructure-based management will help increase the confidence that Wi-Fi 7 can safely operate at the core of sensitive health applications, while still allowing hospital visitors to play games or watch videos. In a factory, it will allow the network infrastructure to make trade-offs appropriate to the environment. These trade-offs will protect production lines from expensive and potentially dangerous disruptions or shutdowns and enable exciting new virtual/augmented reality applications, while still allowing employees on breaks to access their favorite YouTube videos.
All these benefits derive from the network infrastructure’s network-wide view of both operations and goals, in contrast to individual clients that will tend to have a limited view of the network environment and goals that might not be aligned with the greater good. It therefore makes sense for tools like refined versions of Multi-Link Operation and Restricted TWT to be available for use by the network infrastructure, rather than having to rely on disruptive management mechanisms.
Call to action: refine Wi-Fi 7 now to enable network infrastructure-based management tools for enterprise & industrial use cases
It is always a challenge to find the right balance of features as IEEE 802.11 (Wi-Fi) is refined over time. However, a clear requirement for the next generation of Wi-Fi includes effective and practical network infrastructure-based management in enterprise and industrial use cases, highlighting the need for tools like Multi-Link Operation and Restricted TWT to be refined and optimized ASAP. The call to action is for the Wi-Fi community to refine these tools now as part of the first release of IEEE 802.11be and Wi-Fi 7!
Thank you to Brian Hart, Malcolm Smith & Pooya Monajemi for their contributions to this blog!
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