The Preamble

For the final 5 years, I’ve spent appreciable time turning my thoughts to the problems of excellent and dangerous coexistence between Wi-Fi and competing applied sciences, similar to LTE‑U, LAA, and NR‑U, in unlicensed spectrum. I’ve undertaken my pondering within the context of discussions and debates about coexistence in a number of boards, together with IEEE 802, 3GPP, ETSI BRAN, and the Wi-Fi Alliance. I even ended up because the Chair of the IEEE 802.11 Coexistence Standing Committee.

Just lately (June 2022), I used to be requested to summarize the state of play in an IEEE 802 Tech Discuss and my conclusions about what all this dialogue means in apply. The slides of this speak can be found, as is a recording. This weblog is a written model of the IEEE 802 Tech Discuss, higher suited to those that don’t wish to hearken to my dulcet tones for 45 minutes. Even in studying this weblog, you have got a alternative; you possibly can cease on the Govt Abstract, or you possibly can wade by eleven pages of detailed dialogue… take pleasure in!

The brief model: The Govt Abstract

Within the not-so-distant previous, communications providers have been costly, difficult & monopolized by a small variety of service suppliers. Fortuitously, know-how has now enabled a brand new world of communications that’s extremely aggressive and really useful.

Whereas this alteration has been pushed by many components, the emergence of unlicensed spectrum was a key enabler. Wi-Fi, as essentially the most extensively used communications entry answer, has pushed unlicensed spectrum to satisfy its potential and to take action in a means that makes very environment friendly use of spectrum, a scarce and worthwhile neighborhood useful resource. Wi-Fi’s spectrum effectivity is well demonstrated by observing that present use patterns present that Wi-Fi networks carry about twenty instances extra information than mobile networks, regardless of accessing roughly the identical quantity of spectrum.

Wi-Fi has enabled anybody, anytime, wherever to arrange and function a easy, low cost, and versatile wi-fi community of their dwelling or workplace that simply works! This consequence was partially achieved by Wi-Fi’s use of a classy variety of sharing mechanisms that helped keep away from coexistence chaos in lots of difficult sharing environments.

Wi-Fi’s success in unlicensed spectrum (and the brand new unlicensed spectrum justified by that success) has triggered the mobile neighborhood to suggest new cellular-based applied sciences to be used in unlicensed spectrum, together with LAA and NR‑U. The issue is that these techniques solely use a small subset of Wi-Fi’s numerous and complicated sharing mechanisms, with early deployment measurements exhibiting poor coexistence with Wi-Fi techniques (and doubtless between LAA/NR-U techniques too). The seemingly poor coexistence of those mobile applied sciences with Wi-Fi can be a serious financial (and social) drawback, given Wi-Fi’s significance to shoppers and companies and its multi-trillion-dollar international financial worth … yearly!

There could also be nothing to fret about if LAA and NR‑U should not extensively deployed, which is a definite chance. If they’re extensively deployed, important effort might be required to mitigate the potential antagonistic impression on Wi-Fi’s environment friendly and shared use of unlicensed spectrum immediately. Apparently, one mechanism to keep away from coexistence points between Wi-Fi and LAA/NR‑U is to allocate 1200 MHz for unlicensed spectrum in order that the totally different applied sciences can extra simply keep away from working in the identical channel. A greater general answer to maximise client profit is to give attention to utilizing Wi-Fi in unlicensed spectrum & 3GPP’s new NR-based applied sciences in licensed spectrum. This may optimize using each licensed and unlicensed spectrum, avoiding coexistence points without cost!

As regulators seek for essentially the most environment friendly use of spectrum assets, Wi-Fi’s superior sharing traits, widespread adoption, and talent to flexibly meet customers’ wants all stand out as a part of a compelling case to allocate extra unlicensed spectrum, notably within the 6 GHz band.

Key messages

There are a key few messages that I would really like you to remove from this weblog. They’re that:

  • Consumer wants: No matter wi-fi networking options are deployed in licensed or unlicensed spectrum, they need to meet customers’ wants whereas making environment friendly use of spectrum
  • Licensed spectrum:  Unlicensed spectrum (often utilizing Wi-Fi know-how) is essentially the most environment friendly means of assembly consumer’s wants in most environments (notably dwelling and enterprise), however licensed spectrum (utilizing mobile know-how) can be vital to satisfy consumer’s wants in some environments (notably within the wider space and at increased bodily speeds)
  • 6 GHz band is required:  With the introduction of broadband connections that present greater than 10 Gb/s, the complete 1200 MHz of the 6 GHz band is urgently required in order that Wi-Fi can proceed to distribute all the information delivered to end-users and allow new purposes together with Digital Actuality and automation.
  • Give attention to Wi-Fi:  Whereas any know-how is allowed to make use of unlicensed spectrum, a give attention to Wi-Fi is fascinating to keep away from coexistence points that may come up from using unsophisticated sharing mechanisms by applied sciences like LAA and NR-U.

If purchase into my conclusions then I counsel you cease studying now to save lots of 10 minutes of your life. In the event you disagree with my conclusions then I might ask you to dive into the element articulated in the remainder of this weblog. In the event you nonetheless disagree please be happy to contact me to begin a dialogue.

The lengthy model: Give attention to Wi-Fi in expanded unlicensed spectrum in 6 GHz band!

Communications was once costly, difficult & monopolized

One doesn’t have to go very far again in historical past to a time when most technique of communication throughout any distance have been costly, difficult, and relied on providers sometimes offered by monopolistic service suppliers (typically government-owned).

I recall phoning my grandparents in South Africa from Australia every Christmas after I was a toddler (OK, it was half a century in the past), the place we needed to e-book days prematurely for a 3-minute name, after which spent a lot of the name speaking about how costly it was. Even just a few years in the past, many telecommunications clients have been charged huge sums by the minute (or byte), in a fashion that had little or no to do with precise mounted and variable prices.

Communications is now extremely aggressive and useful

The telecommunications world has modified, and for the higher in so many dimensions. Competitors and know-how have helped drive the marginal value of voice and information communications (together with POTS-like, e-mail, and Webex-like providers) throughout the globe to virtually zero. For many individuals, the prices are zero, offset in opposition to revenues to suppliers from promoting or different related enterprise fashions.

The complexity of world communications has additionally considerably decreased, though I think my dad and mom and mother-in-law may disagree. The truth is that the providers themselves are much less advanced, however the selections they supply have massively expanded, typically making every thing appear extra difficult.  They’re definitely extra useful.

Whereas conventional service suppliers nonetheless dominate the availability of facilities-based mobile providers, they face much more competitors within the provision of broadband providers to shoppers and enterprises.  In fact, the need for monopolistic energy by no means goes away, with a brand new era of monopolistic wan-a-bees working increased up the worth chain.

Unlicensed spectrum is a key driver of the fashionable communications

There are lots of causes for this new world of communications, relying on what a part of the ecosystem one focuses on. Actually, the silicon-based know-how revolution that actually took off within the Eighties has had a serious impression on the ecosystem.

Nonetheless, with my Wi-Fi bias, I’m going to say that one thing that began in 1987 was simply as essential. 1987 was the 12 months that the FCC within the US began an experiment that opened the two.4 GHz junk band for unlicensed use. Many older readers might recall the times when organising dwelling or enterprise networks concerned working many meters of cable between routers, desktop computer systems, and different linked gadgets.  This new spectrum, together with Wi-Fi know-how, enabled anybody, anytime, wherever to arrange and function a easy, low cost, and versatile wi-fi community of their dwelling or workplace that simply labored, utilizing an incredible and nonetheless rising number of gadgets & purposes. The FCC experiment was so profitable that it has now unfold globally, additionally increasing into components of the 5 GHz band and (hopefully) all of the 6 GHz band.

Wi-Fi is essentially the most profitable know-how in unlicensed spectrum

The success of Wi-Fi may be measured in numerous methods. A 12 months or so in the past, the Wi-Fi Alliance commissioned critical economists to estimate the financial worth of Wi-Fi in particular international locations and globally. They decided the financial worth of Wi-Fi was 3.3 trillion {dollars} each year in 2021, more likely to develop to 4.9 trillion {dollars} each year in 2025.

Personally, as a measure of Wi-Fi’s success, I’ve at all times favored the surveys undertaken by the Wi-Fi Alliance after I was the Chairman of the Board of Administrators greater than ten years in the past. At the moment, it was found individuals would quite hand over espresso or beer than their Wi-Fi. Espresso and beer are very excessive bars. Nonetheless, this expressed love for Wi-Fi makes good sense when one considers that about 20 instances extra information site visitors immediately goes throughout Wi-Fi networks in comparison with conventional cellular-based networks, which themselves are a significant element of the fashionable communications revolution. This bias in direction of Wi-Fi happens regardless of Wi-Fi accessing about the identical quantity of low and mid-band spectrum as the assorted mobile applied sciences.

Avoiding coexistence chaos

Wi-Fi has sidestepped coexistence chaos in unlicensed spectrum by avoiding different applied sciences, numerous Wi-Fi on Wi-Fi sharing mechanisms and thru self-interest.

Wi-Fi’s great success highlights a captivating query. Why does using a number of applied sciences (together with Wi-Fi) managed by a mess of unmanaged customers working in the identical spectrum not lead to coexistence chaos? There are three foremost solutions from a historic perspective:

  • Totally different channels: Wi-Fi typically doesn’t compete with different applied sciences in the identical channels on the similar time; applied sciences like Bluetooth in 2.4 GHz often keep away from Wi-Fi by working between & past the same old Wi-Fi channels
  • Numerous sharing mechanisms: Wi-Fi features a variety of sharing mechanisms (e.g., Hear Earlier than Discuss, exponential back-off, Preamble Detection, NAV, RTS/CTS, and many others) which can be particularly designed to allow good coexistence between independently managed Wi-Fi networks
  • Self-interest: The IEEE 802.11 Working Group, the Wi-Fi Alliance and the Wi-Fi business extra typically have a vested curiosity in managing coexistence with the deployed Wi-Fi base as new Wi-Fi generations are specified.

Wi-Fi makes use of a variety of sharing mechanisms to advertise coexistence

Wi-Fi know-how was constructed from the very starting to deal with environments the place a number of gadgets with totally different homeowners needed to function in the identical channel. There isn’t any good answer to deal with this very tough drawback. Wi-Fi’s technical answer is to make use of a variety of sharing mechanisms (as famous above), constructed on high of the essential Hear Earlier than Discuss (LBT) mechanism.

LBT avoids transmissions in a channel if another person is already utilizing the identical channel close by. This can be a idea that we’re all used to when speaking across the dinner desk; don’t speak if somebody is already speaking (I want my household would comply with this protocol!). It isn’t an ideal mechanism as a result of a possible transmitter can solely hear the state of the channel on the transmitter and never the place the transmission might trigger interference. Utilizing the dinner desk analogy once more, the individuals on the two ends of a protracted desk may begin speaking as a result of they will’t hear anybody else speaking however the individual within the center finally ends up listening to each of them, and so neither of them correctly (that is typically brought on the hidden station drawback).

The facility of LBT, as practiced by Wi-Fi, is that doesn’t depend on only a single listening mechanism. A Wi-Fi machine defers to different Wi-Fi gadgets at a really low power degree when it’s positive the power comes from one other Wi-Fi machine, by detecting a particular Wi-Fi packet preamble. This is named Preamble Detection and Wi-Fi sometimes makes use of a preamble power detection threshold of -82 dBm. A Wi-Fi machine additionally defers when it hears power with out listening to a preamble. This can be a backup listening mechanism that helps keep away from interfering with different gadgets (utilizing any know-how, together with Wi-Fi), but in addition acknowledges that any transmission made by the Wi-Fi machine in such an surroundings is unlikely to be obtained correctly anyway.

These two listening mechanisms are used to drive a sharing mechanism based mostly on a really outdated and well-proven method known as CSMA/CA (Service Sense A number of Entry with Collision Avoidance). The Wi-Fi model is named EDCA. The concept is that if one other machine is transmitting (or one other individual is speaking on the dinner desk) when your machine desires to transmit then your machine defers for a random interval (that will increase exponentially with every unsuccessful transmission). Once more, that is one thing we’re all used to doing when trying to insert ourselves right into a dialog across the dinner desk (my household makes use of a distinct method … they simply shout louder).

However there’s extra. Wi-Fi additionally permits reserving the channel for restricted durations utilizing a particular subject that’s included in Wi-Fi packets (the particular subject is named NAV – or Community Allocation Vector – and is distributed as a part of the MAC packet, for these technically inclined). This avoids the necessity to rely solely on listening, which, as famous earlier, is imperfect. For instance, the NAV reservation method allows a particular RTS/CTS (Request to Ship/Clear to Ship) mechanism, which helps mitigate the basic hidden station drawback. In our eating room analogy, NAV with RTS/CTS permits the 2 individuals at every finish of our lengthy desk to coordinate after they transmit, regardless that they will’t hear one another in order that the individual within the center can efficiently obtain from each ends of the desk.

Mobile carriers at the moment are utilizing Wi-Fi in unlicensed spectrum

The mobile neighborhood has determined that extra unlicensed spectrum for Wi-Fi unlicensed spectrum couldn’t be ignored and left for Wi-Fi to dominate.

Unlicensed spectrum is technically obtainable to be used by any know-how, so long as it follows primary guidelines set by regulators in numerous international locations. Some regulators apply fairly strict and detailed guidelines, whereas others are extra laisse faire. Nonetheless, unlicensed spectrum (particularly the 5 GHz & 6 GHz bands) is usually known as “Wi-Fi spectrum” (even by many within the mobile neighborhood) as a result of up till now Wi-Fi has been the principle, and infrequently the one, profitable consumer of this unlicensed spectrum.

Nonetheless, many mobile stakeholders have now determined that entry to unlicensed 5 GHz & 6 GHz bands is a chance too worthwhile (or too low cost) to go away for Wi-Fi. After some false begins, many mobile carriers at the moment are utilizing Wi-Fi in unlicensed spectrum to dump site visitors. They’re typically utilizing Wi-Fi offload to offer providers in indoor areas sometimes inaccessible to mobile providers or simply to keep away from deploying very costly mobile applied sciences.

Some mobile stakeholders at the moment are discussing utilizing variations of licensed know-how in unlicensed spectrum instead, regardless of Wi-Fi largely assembly their wants already. One space the place Wi-Fi won’t meet the wants of some mobile stakeholders is that they don’t dominate the possession of the required IPR in the best way they do for mobile applied sciences. In latest instances, 4 new cellular-related applied sciences have been proposed to make use of unlicensed spectrum:

  • LTE‑U (LTE – Unlicensed) from the LTE‑U Discussion board
  • MulteFire from the MulteFire Alliance
  • LAA (License Assisted Entry) & NR‑U (New Radio – Unlicensed) from 3GPP

The proponents of all 4 applied sciences have asserted wonderous advantages in comparison with Wi-Fi, associated to throughput, latency, and reliability, in addition to integration with licensed applied sciences. The truths of those claims are for dialogue at one other time, though I’ll be aware that most of the claims have confirmed to be extra hype quite than actuality.

The primary two applied sciences are not being promoted by the mobile business as a result of they took too lengthy to be specified and launched to the market. Within the case of LTE‑U, a part of the delay was pushed by an issue that arose as a result of LTE‑U was based mostly on a really unusual means of sharing with different applied sciences. Quite than utilizing a distributed sharing mechanism like Wi-Fi the place everyone seems to be roughly equal, it used a egocentric sharing mechanism whereby the LTE‑U system determined what entry it needed and solely then gave the rest to be used by different applied sciences.

3GPP-defined LAA & NR‑U to share unlicensed spectrum utilizing a subset of Wi-Fi’s sharing mechanisms

In newer years, 3GPP has accredited two new specs to be used in unlicensed spectrum; LAA and NR‑U. LAA is a complement to techniques working in licensed spectrum, specializing in utilizing unlicensed spectrum to offer supplementary downlink capability. NR‑U can function independently of techniques working in licensed spectrum, similar to Wi-Fi. As well as, NR‑U appears to deal with very related use circumstances to Wi-Fi. The primary distinction between NR‑U and Wi-Fi is that the previous relies on know-how derived from conventional 3GPP-defined know-how, which tends to be extra advanced and dearer.

LAA and NR‑U resemble Wi-Fi in one other respect, which is essential when discussing the coexistence between the totally different techniques. After a lot debate in 3GPP, strongly influenced by entry guidelines outlined by ETSI BRAN in Europe, LAA and NR‑U have been specified to make use of related sharing mechanisms as Wi-Fi. All three techniques use an EDCA-based model of LBT with exponential back-off and the identical timing parameters. Nonetheless, LAA and NR‑U solely hear for different techniques utilizing power detection (not preamble detection), albeit at a decrease threshold of -72 dBm, and neither LAA nor NR‑U use any of the NAV-based sharing mechanisms which have proved so worthwhile to Wi-Fi over the past 20+ years.

In equity, not utilizing Wi-Fi’s preamble detection or NAV mechanisms makes good sense for LAA and NR‑U, as a result of the adoption of those mechanisms would require elementary adjustments to the standard mobile applied sciences leveraged within the specification of LAA and NR‑U. Certainly, their adoption would primarily require LAA and NR‑U to change into Wi-Fi, which might defeat one objective of the mobile neighborhood defining a substitute for Wi-Fi.

Utilizing solely a subset of sharing mechanisms ends in poor coexistence outcomes

Early measurements of deployed LAA techniques present that utilizing solely a subset of sharing mechanisms ends in poor coexistence outcomes in actual environments.

In depth simulations over a few years in 3GPP and different boards urged that LAA and NR‑U techniques utilizing only a subset of Wi-Fi’s numerous sharing mechanisms would coexist pretty with Wi-Fi techniques, a minimum of within the common case. The massive query is does this declare maintain up in actual deployments in unlicensed spectrum, which regularly should not very common? Sadly, there haven’t been many measurements of actual industrial deployments as a result of LAA, whereas deployed by a restricted variety of operators globally, will not be used extensively. Within the case of NR‑U, there aren’t any identified industrial deployments to measure as of mid-2022.

The measurements which have occurred to date counsel that LAA use of only a subset of Wi-Fi’s sharing mechanisms ends in poor coexistence outcomes. This conclusion relies on work in 2020 and 2021 carried out by researchers on the College of Chicago. Their outcomes have been summarized in two displays in 2021 to the IEEE 802.11 Coexistence Standing Committee (which I chair):

  • LAA/Wi-Fi Coexistence Points: Wi-Fi Shopper Affiliation and Knowledge Transmission by Vanlin Sathya, Muhammed Iqbal Rochman & Monisha Ghosh, 13 Jan 2021 (see 11-20-1973)
  • LAA/Wi-Fi Coexistence Experiments: preliminary outcomes by Monisha Ghosh & Muhammed Iqbal Rochman, 15 Nov 2021 (see 11-21-1858)

These measurement-based research counsel quite a lot of potential underlying issues that aren’t apparent in common simulated environments however are rudely uncovered in real-world environments. It seems these issues trigger LAA (and doubtless NR‑U too) techniques to adversely (and considerably unreasonably) impression Wi-Fi operations:

  • Whereas Wi-Fi techniques typically defer at power ranges of -82 dBm (utilizing preamble detection), LAA techniques solely defer at power ranges above -72 dBm
  • Whereas Wi-Fi techniques have hidden station mitigation mechanisms based mostly on using NAV with RTS/CTS mechanisms, LAA techniques don’t

The College of Chicago researchers should affirm their outcomes at their new dwelling on the College of Notre Dame, and impartial analysis can be wanted.  Nonetheless, for my part, the outcomes are more likely to be broadly appropriate as a result of they are often simply defined.

Making ready for poor coexistence points

Poor coexistence between LAA/NR‑U & Wi-Fi is barely a difficulty if LAA/NR‑U are deployed at scale however business must be prepared for this chance.

The poor coexistence between LAA & Wi-Fi highlighted by the College of Chicago’s research is attention-grabbing from an instructional perspective. Nonetheless, they’re solely essential from a sensible perspective if LAA and NR‑U are deployed extensively.

The excellent news to date is that the deployment trajectory of LAA appears to have stalled globally. Knowledge from GSA exhibits that the variety of operators globally deploying LAA has remained fixed and low (solely 9) for the final 2.5 years. It appears seemingly that even these 9 operators haven’t deployed LAA very extensively.

There are a selection of causes which may drive the restricted long-term deployment of LAA by operators, together with:

  • Operators decide LAA will not be compelling sufficient (or low cost sufficient) in comparison with different applied sciences, notably Wi-Fi
  • Operators are ready for NR‑U, a extra versatile know-how that doesn’t require complementary entry to licensed spectrum
  • Operators perceive the coexistence points between LAA and Wi-Fi and don’t wish to adversely impression Wi-Fi, which is extensively utilized by operators (and their clients)
  • Operators are hoping to steer regulators to specify 700 MHz within the higher 6 GHz band as licensed spectrum, thus avoiding coexistence points with Wi-Fi, or any want to make use of LAA or NR‑U know-how.

We don’t know which of those potentialities will characterize actuality. The underside line is that there are at present many uncertainties and unknowns. There’s nonetheless an actual chance that the large deployment of LAA or NR‑U will trigger critical harm to the multi-trillion-dollar financial and social impression of Wi-Fi on society. On this context, it’s vital to proceed work to grasp the impression of LAA and NR‑U on Wi-Fi operations and start to develop mitigations. I strongly encourage anybody fascinated with these matters to take part within the IEEE 802.11 Coexistence Standing Committee (contact me for particulars on how to do that).

Utilizing Wi-Fi in unlicensed spectrum & NR in licensed spectrum offers the perfect general answer whereas avoiding coexistence issues

There’s a higher answer to keep away from coexistence points between LAA/NR‑U and Wi-Fi in unlicensed spectrum. This higher answer relies on an understanding and recognition that:

  • Wi-Fi is a know-how that already meets the wants of billions of individuals and can proceed to take action as it’s refined by the IEEE 802.11 Working Group and the Wi-Fi Alliance sooner or later
    • The IEEE 802.11 Working Group is growing the subsequent era of Wi-Fi as IEEE 802.11be, which can in all probability be licensed by the Wi-Fi Alliance as Wi-Fi 7 as early as 2024
    • The IEEE 802.11 Working Group can be beginning to focus on the next era, which is more likely to be licensed by the Wi-Fi Alliance as Wi-Fi 8
  • Wi-Fi’s multi-level and numerous sharing mechanisms have proved, over 20+ years, as greater than adequate to offer good (albeit not good) coexistence between impartial techniques in unlicensed spectrum.
    • In distinction, it’s no shock that the one-dimensional power detection centered sharing mechanism utilized by LAA and by NR‑U is insufficient.

The higher answer is to give attention to Wi-Fi as the principle WLAN know-how in unlicensed spectrum as a result of it has been confirmed to offer a wonderful steadiness between efficiency, prices, and coexistence, permitting anybody, wherever, anywhere to arrange a community that simply works! In fact, different applied sciences (similar to Bluetooth, UWB, or WiSun) can be utilized to assist area of interest purposes (noting area of interest doesn’t imply small) the place it may be proven there’s good coexistence. Using Bluetooth within the 2.4 GHz band immediately is an ideal instance of a profitable and smart area of interest use.

This then leaves licensed spectrum to be used primarily by the mobile applied sciences being developed by 3GPP as 5G/6G and enabled by ITU-T as IMT. 5G/6G will primarily be utilized in large areas, excessive energy use, and out of doors use circumstances for which they’re properly suited, Wi-Fi will primarily be used for native areas, low energy, and indoor use circumstances for which it’s so properly suited.  There’ll, in fact, be some overlap between these use circumstances. Quite than worrying about coexistence on the PHY degree, this idea simply requires everybody to give attention to integrating 5G/6G options with Wi-Fi additional up the community stack, with the last word purpose of offering the identical excessive efficiency to shoppers regardless of the place they’re or what they’re doing.

There might also be a case for regionally licensed spectrum that can be utilized by both mobile applied sciences (regionally licensed spectrum might be similar to licensed spectrum for these applied sciences) or by Wi-Fi (regionally licensed spectrum might be similar to a well-managed unlicensed spectrum from the attitude of Wi-Fi).

There’s a important want for extra unlicensed spectrum to assist future demand for information site visitors in an economical and environment friendly method

A coexistence answer based mostly on an acceptance that Wi-Fi is the first know-how in unlicensed spectrum leads us straight into one other up to date debate referring to the allocation of the 6 GHz band for unlicensed use (primarily by Wi-Fi) or licensed use (primarily by 5G/6G licensed applied sciences below the IMT banner). In most components of the world, it has already been agreed that the decrease 500 MHz of the 6 GHz band might be allotted for unlicensed use. This response to the truth that Wi-Fi site visitors is doubling each 3 years, and the prevailing 2.4 GHz and 5 GHz bands are shortly changing into congested. As new data-intensive purposes like AR/VR change into extra widespread, the calls for on the prevailing unlicensed spectrum might change into unsustainable. Even with Wi-Fi’s flexibility and strong coexistence capabilities, new spectrum bands are vital to deal with this growing demand.

The primary present debate is in regards to the higher 700 MHz of the 6 GHz band (which extends into the 7 GHz band). In some international locations, the higher 6 GHz band has already been allotted for unlicensed use (e.g., the US, Brazil, and Saudi Arabia). In different international locations (e.g., throughout Europe), there’s an ongoing debate that may in all probability not be resolved till the ITU-R WRC-2023 convention on the finish of 2023.

The talk in regards to the allocation of the higher 6 GHz band is multi-dimensional, with a lot of handwaving and self-serving arguments, typically based mostly on unsupported and really enthusiastic assumptions. Either side of the talk assert that extra spectrum is required to assist rising consumer wants for extra information. At the very least on that time, there’s settlement:

  • These arguing for the higher 6 GHz band to be licensed to be used by 5G/6G (or IMT) assert that solely operators utilizing licensed spectrum can present the providers wanted by customers (presumably for an oligopoly-defined payment). Apparently, in making this argument they appear to be abandoning the concept their very own LAA/NR‑U know-how can service customers in unlicensed spectrum.
  • These arguing for the higher 6 GHz band to be unlicensed, primarily to be used by Wi-Fi, assert that doing so will permit for anybody, wherever, anywhere to arrange a community that simply works, inherently assembly customers’ wants (at a cost-driven in direction of zero by competitors and selection).

Quite than counting on the handwaving by each side to resolve this debate, it is likely to be higher to depend on some details. In 2022, utilizing Europe for example, on the idea {that a} decision of this debate within the context of Europe may have a big impression globally:

  • Applied sciences, like 4G/5G/6G, that use licensed spectrum have entry to simply greater than 1000 MHz of low band and mid-band spectrum …
  • … and applied sciences, like Wi-Fi, that use unlicensed spectrum have entry to about 1000 MHz of low band and mid-band spectrum (together with the decrease 6 GHz band however excluding the higher 6 GHz band)
  • … and but (utilizing 2021 information from the German Ministry for Financial Affairs & Local weather) the huge bulk of knowledge immediately is transmitted over Wi-Fi
    • Cell networks in Germany in 2021: 4 Exa Bytes (5%)
    • Fastened networks (largely Wi-Fi) in Germany in 2021: 76 Exa Bytes (95%)
  • … that is more likely to develop sooner or later, supported by mounted broadband backhaul hyperlinks to properties and companies more and more supporting charges of greater than 10 Gb/s.

These details clearly reveal that unlicensed spectrum, utilizing applied sciences like Wi-Fi, satisfies the wants of most customers immediately, in a fashion that’s considerably extra environment friendly (as much as 20 instances extra environment friendly) and versatile than licensed spectrum. It sometimes does so at a a lot decrease value to the consumer. It isn’t tough to additionally conclude that the good thing about offering one other 700 MHz for unlicensed use has a considerably larger “bang for the buck” than allocating it to 5G/6G operators for licensed use.

It’s potential none of this rational and evidence-based argument issues very a lot to these within the mobile neighborhood who’re advocating for the higher 6 GHz band (and even the entire 6 GHz band) to be licensed. Perhaps they acknowledge unlicensed spectrum actually is the higher and extra versatile strategy to fulfill customers’ wants and Wi-Fi might be much more in a position to assist customers’ wants by making all the 6 GHz bands unlicensed. Nonetheless, perhaps their actual purpose has nothing to do with satisfying customers’ wants however as a substitute is all about blocking Wi-Fi in no matter means they will in an effort to guard their mobile know-how/licensed spectrum-based oligopolies.

Allocating the complete 6 GHz band for unlicensed use has one ultimate profit, taking us all the best way again to the query of coexistence. Extra unlicensed spectrum within the 6 GHz band makes it simpler for LAA/NR‑U to function in several channels from Wi-Fi, thus avoiding poor coexistence outcomes between the totally different applied sciences. That is like how we keep away from poor coexistence outcomes between Wi-Fi and Bluetooth within the 2.4 GHz band. Alternatively, we might use simply Wi-Fi in 6 GHz unlicensed bands, specializing in NR know-how within the licensed bands …

A Conclusion: Allocate the complete 6 GHz for unlicensed use, primarily by Wi-Fi to keep away from coexistence points!

Congratulations on getting this far. I put my conclusions up entrance within the Govt Abstract, however I’ve been advised I have to put my conclusions on the finish too! So right here they’re once more …

  • No matter wi-fi networking options are deployed in licensed or unlicensed spectrum, they need to meet customers’ wants whereas making environment friendly use of spectrum
  • Unlicensed spectrum (often utilizing Wi-Fi know-how) is essentially the most environment friendly means of assembly consumer’s wants in most environments (notably dwelling and enterprise), however licensed spectrum (utilizing mobile know-how) can be vital to satisfy consumer’s wants in some environments (notably within the wider space and at increased speeds)
  • With the introduction of broadband connections that present greater than 10 Gb/s, the complete 1200 MHz of the 6 GHz band is urgently required in order that Wi-Fi can proceed to distribute all the information delivered to end-users and allow new purposes, together with Digital Actuality and automation.
  • Whereas any know-how is allowed to make use of unlicensed spectrum, a give attention to Wi-Fi is fascinating to keep away from coexistence points that may come up from using unsophisticated sharing mechanisms by applied sciences like LAA and NR-U.



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