Wi-Fi is “the” unlicensed spectrum expertise…and it wants entry to extra unlicensed spectrum!

The Preamble

For the final 5 years, I’ve spent appreciable time turning my thoughts to the problems of fine and unhealthy coexistence between Wi-Fi and competing applied sciences, resembling 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.

Not too long ago (June 2022), I used to be requested to summarize the state of play in an IEEE 802 Tech Speak and my conclusions about what all this dialogue means in observe. The slides of this speak can be found, as is a recording. This weblog is a written model of the IEEE 802 Tech Speak, higher suited to those that don’t wish to take heed to my dulcet tones for 45 minutes. Even in studying this weblog, you’ve a selection; you may cease on the Government Abstract, or you may wade by way of eleven pages of detailed dialogue… get pleasure from!

The brief model: The Government Abstract

Within the not-so-distant previous, communications companies had been costly, sophisticated & monopolized by a small variety of service suppliers. Luckily, expertise has now enabled a brand new world of communications that’s extremely aggressive and really purposeful.

Whereas this modification has been pushed by many elements, the emergence of unlicensed spectrum was a key enabler. Wi-Fi, as probably 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 occasions extra information than mobile networks, regardless of getting access to 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 residence 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 methods solely use a small subset of Wi-Fi’s various and complicated sharing mechanisms, with early deployment measurements exhibiting poor coexistence with Wi-Fi methods (and possibly between LAA/NR-U methods too). The possible poor coexistence of those mobile applied sciences with Wi-Fi could be a serious financial (and social) downside, given Wi-Fi’s significance to shoppers and companies and its multi-trillion-dollar world financial worth … yearly!

There could also be nothing to fret about if LAA and NR‑U are usually not extensively deployed, which is a definite chance. If they’re extensively deployed, vital effort shall be required to mitigate the potential adversarial influence 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 total answer to maximise client profit is to deal with utilizing Wi-Fi in unlicensed spectrum & 3GPP’s new NR-based applied sciences in licensed spectrum. This can optimize the usage of each licensed and unlicensed spectrum, avoiding coexistence points at no cost!

As regulators seek for probably the most environment friendly use of spectrum sources, 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:

  • Person wants: No matter wi-fi networking options are deployed in licensed or unlicensed spectrum, they have to meet customers’ wants whereas making environment friendly use of spectrum
  • Licensed spectrum:  Unlicensed spectrum (normally utilizing Wi-Fi expertise) is probably the most environment friendly means of assembly person’s wants in most environments (notably residence and enterprise), however licensed spectrum (utilizing mobile expertise) can be mandatory to satisfy person’s wants in some environments (notably within the wider space and at greater bodily speeds)
  • 6 GHz band is required:  With the introduction of broadband connections that present greater than 10 Gb/s, the total 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.
  • Concentrate on Wi-Fi:  Whereas any expertise is allowed to make use of unlicensed spectrum, a deal with Wi-Fi is fascinating to keep away from coexistence points that can come up from the usage of unsophisticated sharing mechanisms by applied sciences like LAA and NR-U.

If purchase into my conclusions then I counsel you cease studying now to avoid wasting 10 minutes of your life. In case you disagree with my conclusions then I’d ask you to dive into the element articulated in the remainder of this weblog. In case you nonetheless disagree please be at liberty to contact me to begin a dialogue.

The lengthy model: Concentrate on Wi-Fi in expanded unlicensed spectrum in 6 GHz band!

Communications was costly, sophisticated & monopolized

One doesn’t must go very far again in historical past to a time when most technique of communication throughout any distance had been costly, sophisticated, and relied on companies usually supplied by monopolistic service suppliers (usually government-owned).

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

Communications is now extremely aggressive and purposeful

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

The complexity of world communications has additionally considerably decreased, though I believe my mother and father and mother-in-law would possibly disagree. The fact is that the companies themselves are much less advanced, however the decisions they supply have massively expanded, generally making every little thing appear extra sophisticated.  They’re actually extra purposeful.

Whereas conventional service suppliers nonetheless dominate the supply of facilities-based mobile companies, they face much more competitors within the provision of broadband companies to shoppers and enterprises.  After all, the will for monopolistic energy by no means goes away, with a brand new technology of monopolistic wan-a-bees working greater 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 expertise revolution that basically took off within the Nineteen Eighties has had a serious influence on the ecosystem.

Nevertheless, with my Wi-Fi bias, I’m going to say that one thing that began in 1987 was simply as vital. 1987 was the yr that the FCC within the US began an experiment that opened the two.4 GHz junk band for unlicensed use. Many older readers could recall the times when organising residence or enterprise networks concerned operating many meters of cable between routers, desktop computer systems, and different linked units.  This new spectrum, together with Wi-Fi expertise, enabled anybody, anytime, wherever to arrange and function a easy, low-cost, and versatile wi-fi community of their residence or workplace that simply labored, utilizing a tremendous and nonetheless rising number of units & 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 probably the most profitable expertise in unlicensed spectrum

The success of Wi-Fi might be measured in varied methods. A yr 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, prone to develop to 4.9 trillion {dollars} each year in 2025.

Personally, as a measure of Wi-Fi’s success, I’ve all the time preferred the surveys undertaken by the Wi-Fi Alliance once I was the Chairman of the Board of Administrators greater than ten years in the past. At the moment, it was found individuals would slightly surrender espresso or beer than their Wi-Fi. Espresso and beer are very excessive bars. Nevertheless, this expressed love for Wi-Fi makes excellent sense when one considers that about 20 occasions extra information visitors immediately goes throughout Wi-Fi networks in comparison with conventional cellular-based networks, which themselves are an important part of the fashionable communications revolution. This bias in direction of Wi-Fi happens regardless of Wi-Fi getting access to about the identical quantity of low and mid-band spectrum as the varied mobile applied sciences.

Avoiding coexistence chaos

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

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

  • Totally different channels: Wi-Fi usually doesn’t compete with different applied sciences in the identical channels on the identical time; applied sciences like Bluetooth in 2.4 GHz normally keep away from Wi-Fi by working between & past the standard Wi-Fi channels
  • Various sharing mechanisms: Wi-Fi features a variety of sharing mechanisms (e.g., Pay attention Earlier than Speak, exponential back-off, Preamble Detection, NAV, RTS/CTS, and so on) which are 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 usually 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 expertise was constructed from the very starting to deal with environments the place a number of units with totally different homeowners needed to function in the identical channel. There is no such thing as a excellent answer to deal with this very tough downside. Wi-Fi’s technical answer is to make use of a variety of sharing mechanisms (as famous above), constructed on prime of the essential Pay attention Earlier than Speak (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 observe this protocol!). It’s not 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 could trigger interference. Utilizing the dinner desk analogy once more, the individuals on the two ends of an extended desk would possibly begin speaking as a result of they’ll’t hear anybody else speaking however the particular person within the center finally ends up listening to each of them, and so neither of them correctly (that is usually triggered the hidden station downside).

The ability 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 units at a really low vitality degree when it’s positive the vitality comes from one other Wi-Fi machine, by detecting a particular Wi-Fi packet preamble. This is named Preamble Detection and Wi-Fi usually makes use of a preamble vitality detection threshold of -82 dBm. A Wi-Fi machine additionally defers when it hears vitality with out listening to a preamble. This can be a backup listening mechanism that helps keep away from interfering with different units (utilizing any expertise, together with Wi-Fi), but in addition acknowledges that any transmission made by the Wi-Fi machine in such an setting 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 (Provider Sense A number of Entry with Collision Avoidance). The Wi-Fi model is known as EDCA. The concept is that if one other machine is transmitting (or one other particular person is speaking on the dinner desk) when your machine needs 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 unique method … they simply shout louder).

However there may be extra. Wi-Fi additionally permits reserving the channel for restricted intervals utilizing a particular discipline that’s included in Wi-Fi packets (the particular discipline is known as NAV – or Community Allocation Vector – and is shipped 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 traditional hidden station downside. In our eating room analogy, NAV with RTS/CTS permits the 2 individuals at every finish of our lengthy desk to coordinate once they transmit, though they’ll’t hear one another in order that the particular person within the center can efficiently obtain from each ends of the desk.

Mobile carriers are actually 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 accessible to be used by any expertise, so long as it follows fundamental guidelines set by regulators in varied international locations. Some regulators apply fairly strict and detailed guidelines, whereas others are extra laisse faire. Nevertheless, unlicensed spectrum (particularly the 5 GHz & 6 GHz bands) is commonly known as “Wi-Fi spectrum” (even by many within the mobile neighborhood) as a result of up till now Wi-Fi has been the primary, and infrequently the one, profitable person of this unlicensed spectrum.

Nevertheless, 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 depart for Wi-Fi. After some false begins, many mobile carriers are actually utilizing Wi-Fi in unlicensed spectrum to dump visitors. They’re usually utilizing Wi-Fi offload to supply companies in indoor areas usually inaccessible to mobile companies or simply to keep away from deploying very costly mobile applied sciences.

Some mobile stakeholders are actually discussing utilizing variations of licensed expertise in unlicensed spectrum as a substitute, regardless of Wi-Fi principally assembly their wants already. One space the place Wi-Fi may not meet the wants of some mobile stakeholders is that they don’t dominate the possession of the required IPR in the way in which they do for mobile applied sciences. In latest occasions, 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 word that lots of the claims have confirmed to be extra hype slightly than actuality.

The primary two applied sciences are now 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. Slightly 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 wished 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 authorised two new specs to be used in unlicensed spectrum; LAA and NR‑U. LAA is a complement to methods working in licensed spectrum, specializing in utilizing unlicensed spectrum to supply supplementary downlink capability. NR‑U can function independently of methods working in licensed spectrum, similar to Wi-Fi. As well as, NR‑U appears to handle very comparable use circumstances to Wi-Fi. The primary distinction between NR‑U and Wi-Fi is that the previous is predicated on expertise derived from conventional 3GPP-defined expertise, 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 methods. After a lot debate in 3GPP, strongly influenced by entry guidelines outlined by ETSI BRAN in Europe, LAA and NR‑U had been specified to make use of comparable sharing mechanisms as Wi-Fi. All three methods use an EDCA-based model of LBT with exponential back-off and the identical timing parameters. Nevertheless, LAA and NR‑U solely hear for different methods utilizing vitality 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 during the last 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 basic adjustments to the normal 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 an alternative choice to Wi-Fi.

Utilizing solely a subset of sharing mechanisms leads to poor coexistence outcomes

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

In depth simulations over a few years in 3GPP and different boards prompt that LAA and NR‑U methods utilizing only a subset of Wi-Fi’s various sharing mechanisms would coexist pretty with Wi-Fi methods, a minimum of within the common case. The massive query is does this declare maintain up in actual deployments in unlicensed spectrum, which frequently are usually 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, just isn’t used extensively. Within the case of NR‑U, there are not any identified industrial deployments to measure as of mid-2022.

The measurements which have occurred thus far counsel that LAA use of only a subset of Wi-Fi’s sharing mechanisms leads to poor coexistence outcomes. This conclusion is predicated on work in 2020 and 2021 performed by researchers on the College of Chicago. Their outcomes had been summarized in two shows in 2021 to the IEEE 802.11 Coexistence Standing Committee (which I chair):

  • LAA/Wi-Fi Coexistence Points: Wi-Fi Shopper Affiliation and Information 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 possibly NR‑U too) methods to adversely (and considerably unreasonably) influence Wi-Fi operations:

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

The College of Chicago researchers should verify their outcomes at their new residence on the College of Notre Dame, and impartial analysis can be wanted.  Nevertheless, in my view, the outcomes are prone to be broadly appropriate as a result of they are often simply defined.

Getting 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 educational perspective. Nevertheless, they’re solely vital from a sensible perspective if LAA and NR‑U are deployed extensively.

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

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

  • Operators decide LAA just isn’t compelling sufficient (or low-cost sufficient) in comparison with different applied sciences, notably Wi-Fi
  • Operators are ready for NR‑U, a extra versatile expertise 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 influence Wi-Fi, which is extensively utilized by operators (and their prospects)
  • 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 expertise.

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 injury to the multi-trillion-dollar financial and social influence of Wi-Fi on society. On this context, it’s critical to proceed work to grasp the influence of LAA and NR‑U on Wi-Fi operations and start to develop mitigations. I strongly encourage anybody all for these subjects 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 most effective total 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 is predicated on an understanding and recognition that:

  • Wi-Fi is a expertise 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 creating the subsequent technology of Wi-Fi as IEEE 802.11be, which is able to most likely 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 technology, which is prone to be licensed by the Wi-Fi Alliance as Wi-Fi 8
  • Wi-Fi’s multi-level and various sharing mechanisms have proved, over 20+ years, as greater than ample to supply good (albeit not excellent) coexistence between impartial methods in unlicensed spectrum.
    • In distinction, it’s no shock that the one-dimensional vitality detection targeted sharing mechanism utilized by LAA and by NR‑U is insufficient.

The higher answer is to deal with Wi-Fi as the primary WLAN expertise in unlicensed spectrum as a result of it has been confirmed to supply a wonderful stability between efficiency, prices, and coexistence, permitting anybody, wherever, anywhere to arrange a community that simply works! After all, different applied sciences (resembling Bluetooth, UWB, or WiSun) can be utilized to help area of interest purposes (noting area of interest doesn’t imply small) the place it may be proven there may be good coexistence. The usage of 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 outside 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, after all, be some overlap between these use circumstances. Slightly than worrying about coexistence on the PHY degree, this idea simply requires everybody to deal with integrating 5G/6G options with Wi-Fi additional up the community stack, with the last word aim of offering the identical excessive efficiency to shoppers regardless of the place they’re or what they’re doing.

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

There’s a vital want for extra unlicensed spectrum to help future demand for information visitors in a cheap and environment friendly method

A coexistence answer based mostly on an acceptance that Wi-Fi is the first expertise in unlicensed spectrum leads us straight into one other up to date debate regarding the allocation of the 6 GHz band for unlicensed use (primarily by Wi-Fi) or licensed use (primarily by 5G/6G licensed applied sciences beneath the IMT banner). In most components of the world, it has already been agreed that the decrease 500 MHz of the 6 GHz band shall be allotted for unlicensed use. This response to the truth that Wi-Fi visitors is doubling each 3 years, and the prevailing 2.4 GHz and 5 GHz bands are rapidly turning 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 mandatory to handle 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 may be an ongoing debate that can most likely 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 number of handwaving and self-serving arguments, usually based mostly on unsupported and really enthusiastic assumptions. Either side of the controversy assert that extra spectrum is required to help rising person wants for extra information. A minimum of on that time, there may be 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 companies 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 expertise 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 enable 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).

Slightly than counting on the handwaving by either side to resolve this debate, it could be higher to depend on some details. In 2022, utilizing Europe for instance, on the premise {that a} decision of this debate within the context of Europe could have a major influence 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 information immediately is transmitted over Wi-Fi
    • Cellular networks in Germany in 2021: 4 Exa Bytes (5%)
    • Mounted networks (principally Wi-Fi) in Germany in 2021: 76 Exa Bytes (95%)
  • … that is prone to develop sooner or later, supported by fastened broadband backhaul hyperlinks to houses 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 occasions extra environment friendly) and versatile than licensed spectrum. It usually does so at a a lot decrease value to the person. It’s not tough to additionally conclude that the good thing about offering one other 700 MHz for unlicensed use has a considerably better “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. Possibly they acknowledge unlicensed spectrum actually is the higher and extra versatile technique to fulfill customers’ wants and Wi-Fi shall be much more in a position to help customers’ wants by making all the 6 GHz bands unlicensed. Nevertheless, possibly their actual aim has nothing to do with satisfying customers’ wants however as an alternative is all about blocking Wi-Fi in no matter means they’ll in an effort to guard their mobile expertise/licensed spectrum-based oligopolies.

Allocating your complete 6 GHz band for unlicensed use has one remaining profit, taking us all the way in which again to the query of coexistence. Extra unlicensed spectrum within the 6 GHz band makes it simpler for LAA/NR‑U to function in numerous 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 expertise within the licensed bands …

A Conclusion: Allocate your 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 Government Abstract, however I’ve been instructed I must 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 have to meet customers’ wants whereas making environment friendly use of spectrum
  • Unlicensed spectrum (normally utilizing Wi-Fi expertise) is probably the most environment friendly means of assembly person’s wants in most environments (notably residence and enterprise), however licensed spectrum (utilizing mobile expertise) can be mandatory to satisfy person’s wants in some environments (notably within the wider space and at greater speeds)
  • With the introduction of broadband connections that present greater than 10 Gb/s, the total 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 expertise is allowed to make use of unlicensed spectrum, a deal with Wi-Fi is fascinating to keep away from coexistence points that can come up from the usage of unsophisticated sharing mechanisms by applied sciences like LAA and NR-U.



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