The Preamble
For the final 5 years, I’ve spent appreciable time turning my thoughts to the problems of fine and dangerous coexistence between Wi-Fi and competing applied sciences, comparable 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 Speak and my conclusions about what all this dialogue means in observe. The slides of this discuss 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 need to hearken to my dulcet tones for 45 minutes. Even in studying this weblog, you will have a alternative; you’ll be able to cease on the Government Abstract, or you’ll be able to wade via eleven pages of detailed dialogue… take pleasure in!
The brief model: The Government Abstract
Within the not-so-distant previous, communications companies had been costly, difficult & monopolized by a small variety of service suppliers. Happily, know-how has now enabled a brand new world of communications that’s extremely aggressive and really purposeful.
Whereas this alteration has been pushed by many elements, the emergence of unlicensed spectrum was a key enabler. Wi-Fi, as essentially the most extensively used communications entry resolution, has pushed unlicensed spectrum to satisfy its potential and to take action in a method that makes very environment friendly use of spectrum, a scarce and invaluable 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 getting access to roughly the identical quantity of spectrum.
Wi-Fi has enabled anybody, anytime, anyplace 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 complicated range 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 various and complex sharing mechanisms, with early deployment measurements exhibiting poor coexistence with Wi-Fi techniques (and possibly between LAA/NR-U techniques too). The possible poor coexistence of those mobile applied sciences with Wi-Fi can 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 aren’t extensively deployed, which is a definite risk. If they’re extensively deployed, vital effort will likely be required to mitigate the potential opposed impression on Wi-Fi’s environment friendly and shared use of unlicensed spectrum right this moment. Curiously, 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 completely different applied sciences can extra simply keep away from working in the identical channel. A greater general resolution 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 can optimize using each licensed and unlicensed spectrum, avoiding coexistence points without cost!
As regulators seek for essentially the most environment friendly use of spectrum sources, Wi-Fi’s superior sharing traits, widespread adoption, and skill to flexibly meet customers’ wants all stand out as a part of a compelling case to allocate extra unlicensed spectrum, significantly 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 method of assembly consumer’s wants in most environments (significantly dwelling and enterprise), however licensed spectrum (utilizing mobile know-how) can also be essential to fulfill consumer’s wants in some environments (significantly within the wider space and at larger 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 the entire information delivered to end-users and allow new functions together with Digital Actuality and automation.
- Deal with 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 can 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 avoid wasting 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 at liberty to contact me to start out a dialogue.
The lengthy model: Deal with Wi-Fi in expanded unlicensed spectrum in 6 GHz band!
Communications was once costly, difficult & 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, difficult, and relied on companies 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 guide 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 clients had 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 purposeful
The telecommunications world has modified, and for the higher in so many dimensions. Competitors and know-how have helped drive the marginal price 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 in opposition to revenues to suppliers from promoting or different related enterprise fashions.
The complexity of world communications has additionally considerably decreased, though I believe my dad and mom and mother-in-law would possibly disagree. The truth is that the companies themselves are much less complicated, however the decisions they supply have massively expanded, typically making every little thing appear extra difficult. They’re actually extra purposeful.
Whereas conventional service suppliers nonetheless dominate the availability of facilities-based mobile companies, they face way 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 era of monopolistic wan-a-bees working larger up the worth chain.
Unlicensed spectrum is a key driver of the trendy communications
There are a lot of causes for this new world of communications, relying on what a part of the ecosystem one focuses on. Definitely, the silicon-based know-how revolution that basically took off within the Nineteen 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 vital. 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 could recall the times when establishing dwelling or enterprise networks concerned operating 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, anyplace 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 & functions. 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 will be measured in numerous methods. A 12 months or so in the past, the Wi-Fi Alliance commissioned severe 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} every year in 2021, prone to develop to 4.9 trillion {dollars} every year in 2025.
Personally, as a measure of Wi-Fi’s success, I’ve all the time appreciated 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 folks 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 visitors right this moment goes throughout Wi-Fi networks in comparison with conventional cellular-based networks, which themselves are an important part of the trendy communications revolution. This bias in the direction of Wi-Fi happens regardless of Wi-Fi getting access to 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, various Wi-Fi on Wi-Fi sharing mechanisms and thru self-interest.
Wi-Fi’s super success highlights an interesting 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 end in 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 standard Wi-Fi channels
- Various sharing mechanisms: Wi-Fi features a range of sharing mechanisms (e.g., Pay attention Earlier than Speak, exponential back-off, Preamble Detection, NAV, RTS/CTS, and so forth) 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 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 range 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 completely different house owners needed to function in the identical channel. There is no such thing as a good resolution to deal with this very troublesome downside. Wi-Fi’s technical resolution is to make use of a range of sharing mechanisms (as famous above), constructed on prime of the fundamental 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 discuss 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 could trigger interference. Utilizing the dinner desk analogy once more, the folks on the two ends of a protracted desk would possibly begin speaking as a result of they’ll’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 about the hidden station downside).
The facility of LBT, as practiced by Wi-Fi, is that doesn’t depend on only a single listening mechanism. A Wi-Fi gadget defers to different Wi-Fi gadgets at a really low vitality degree when it’s positive the vitality comes from one other Wi-Fi gadget, by detecting a particular Wi-Fi packet preamble. This is called Preamble Detection and Wi-Fi sometimes makes use of a preamble vitality detection threshold of -82 dBm. A Wi-Fi gadget 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 gadgets (utilizing any know-how, together with Wi-Fi), but additionally acknowledges that any transmission made by the Wi-Fi gadget in such an atmosphere is unlikely to be acquired correctly anyway.
These two listening mechanisms are used to drive a sharing mechanism primarily based on a really previous and well-proven method referred to 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 gadget is transmitting (or one other individual is speaking on the dinner desk) when your gadget needs to transmit then your gadget 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 making an attempt 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 traditional hidden station downside. In our eating room analogy, NAV with RTS/CTS permits the 2 folks at every finish of our lengthy desk to coordinate after they transmit, despite the fact that they’ll’t hear one another in order that the individual 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 know-how, so long as it follows fundamental 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 referred to 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 sometimes 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 invaluable (or too low cost) to go away for Wi-Fi. After some false begins, many mobile carriers are actually utilizing Wi-Fi in unlicensed spectrum to dump visitors. They’re typically utilizing Wi-Fi offload to supply companies in indoor areas sometimes 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 know-how in unlicensed spectrum as a substitute, regardless of Wi-Fi principally 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 notice 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 primarily based on a really unusual method of sharing with different applied sciences. Somewhat 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 more moderen 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 supply 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 principle distinction between NR‑U and Wi-Fi is that the previous is predicated on know-how derived from conventional 3GPP-defined know-how, which tends to be extra complicated and costlier.
LAA and NR‑U resemble Wi-Fi in one other respect, which is essential when discussing the coexistence between the completely different techniques. 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 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 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 invaluable 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 modifications to the standard mobile applied sciences leveraged within the specification of LAA and NR‑U. Certainly, their adoption would basically require LAA and NR‑U to change into Wi-Fi, which might defeat one goal 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 techniques present that utilizing solely a subset of sharing mechanisms leads to poor coexistence outcomes in actual environments.
Intensive simulations over a few years in 3GPP and different boards steered that LAA and NR‑U techniques utilizing only a subset of Wi-Fi’s various 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 frequently aren’t very common? Sadly, there haven’t been many measurements of actual business deployments as a result of LAA, whereas deployed by a restricted variety of operators globally, isn’t used extensively. Within the case of NR‑U, there are not any recognized business deployments to measure as of mid-2022.
The measurements which have occurred up to now 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) techniques to adversely (and considerably unreasonably) impression Wi-Fi operations:
- Whereas Wi-Fi techniques typically defer at vitality ranges of -82 dBm (utilizing preamble detection), LAA techniques solely defer at vitality ranges above -72 dBm
- Whereas Wi-Fi techniques have hidden station mitigation mechanisms primarily based on using NAV with RTS/CTS mechanisms, LAA techniques don’t
The College of Chicago researchers should verify their outcomes at their new dwelling on the College of Notre Dame, and unbiased analysis can also be wanted. Nonetheless, for my part, 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 problem if LAA/NR‑U are deployed at scale however business must be prepared for this risk.
The poor coexistence between LAA & Wi-Fi highlighted by the College of Chicago’s research is attention-grabbing from a tutorial perspective. Nonetheless, they’re solely vital from a sensible perspective if LAA and NR‑U are deployed extensively.
The excellent news up to now 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 selection of causes which may drive the restricted long-term deployment of LAA by operators, together with:
- Operators decide LAA isn’t compelling sufficient (or low cost sufficient) in comparison with different applied sciences, significantly 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 need 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 prospects will characterize actuality. The underside line is that there are at present many uncertainties and unknowns. There may be nonetheless an actual risk that the broad deployment of LAA or NR‑U will trigger severe harm to the multi-trillion-dollar financial and social impression of Wi-Fi on society. On this context, it’s critical to proceed work to know the impression of LAA and NR‑U on Wi-Fi operations and start to develop mitigations. I strongly encourage anybody concerned 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 one of the best general resolution whereas avoiding coexistence issues
There’s a higher resolution to keep away from coexistence points between LAA/NR‑U and Wi-Fi in unlicensed spectrum. This higher resolution is predicated 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 creating 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 also be beginning to talk about the next era, 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 enough to supply good (albeit not good) coexistence between unbiased techniques 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 resolution 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 supply a superb stability between efficiency, prices, and coexistence, permitting anybody, anyplace, anyplace to arrange a community that simply works! After all, different applied sciences (comparable to Bluetooth, UWB, or WiSun) can be utilized to assist area of interest functions (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 right this moment is an ideal instance of a profitable and wise 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 broad areas, excessive energy use, and outside use circumstances for which they’re effectively suited, Wi-Fi will primarily be used for native areas, low energy, and indoor use circumstances for which it’s so effectively suited. There’ll, after all, be some overlap between these use circumstances. Somewhat 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 may additionally be a case for domestically licensed spectrum that can be utilized by both mobile applied sciences (domestically licensed spectrum will likely be similar to licensed spectrum for these applied sciences) or by Wi-Fi (domestically licensed spectrum will likely be similar to a well-managed unlicensed spectrum from the attitude of Wi-Fi).
There’s a vital want for added unlicensed spectrum to assist future demand for information visitors in a cheap and environment friendly method
A coexistence resolution primarily based 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 will likely be allotted for unlicensed use. This response to the truth that Wi-Fi visitors is doubling each 3 years, and the present 2.4 GHz and 5 GHz bands are shortly turning into congested. As new data-intensive functions like AR/VR change into extra widespread, the calls for on the present unlicensed spectrum might change into unsustainable. Even with Wi-Fi’s flexibility and strong coexistence capabilities, new spectrum bands are essential to deal with this growing demand.
The principle 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 can 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 number of handwaving and self-serving arguments, typically primarily based on unsupported and really enthusiastic assumptions. Each side of the talk assert that extra spectrum is required to assist rising consumer wants for extra information. A minimum of 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 companies wanted by customers (presumably for an oligopoly-defined price). Curiously, in making this argument they appear to be abandoning the concept that 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, anyplace, anyplace to arrange a community that simply works, inherently assembly customers’ wants (at a cost-driven in the direction of zero by competitors and selection).
Somewhat than counting on the handwaving by either side to resolve this debate, it is likely to be higher to depend on some information. In 2022, utilizing Europe for instance, on the idea {that a} decision of this debate within the context of Europe could 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 right this moment 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 mounted broadband backhaul hyperlinks to properties and companies more and more supporting charges of greater than 10 Gb/s.
These information clearly reveal that unlicensed spectrum, utilizing applied sciences like Wi-Fi, satisfies the wants of most customers right this moment, 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 price to the consumer. It isn’t troublesome 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 attainable 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 strategy to fulfill customers’ wants and Wi-Fi will likely be much more in a position to assist customers’ wants by making the entire 6 GHz bands unlicensed. Nonetheless, perhaps their actual purpose has nothing to do with satisfying customers’ wants however as an alternative is all about blocking Wi-Fi in no matter method they’ll in an effort to guard their mobile know-how/licensed spectrum-based oligopolies.
Allocating all the 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 completely 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 all the 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 advised 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 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 method of assembly consumer’s wants in most environments (significantly dwelling and enterprise), however licensed spectrum (utilizing mobile know-how) can also be essential to fulfill consumer’s wants in some environments (significantly within the wider space and at larger 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 the entire information delivered to end-users and allow new functions, 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 can come up from using unsophisticated sharing mechanisms by applied sciences like LAA and NR-U.
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