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, similar to LTE‑U, LAA, and NR‑U, in unlicensed spectrum. I’ve undertaken my considering 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 discuss 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 need to take heed to my dulcet tones for 45 minutes. Even in studying this weblog, you’ve got a alternative; you’ll be able to cease on the Govt Abstract, or you’ll be able to wade via eleven pages of detailed dialogue… get pleasure from!
The quick model: The Govt Abstract
Within the not-so-distant previous, communications providers have been costly, sophisticated & monopolized by a small variety of service suppliers. Luckily, know-how has now enabled a brand new world of communications that’s extremely aggressive and really practical.
Whereas this transformation has been pushed by many components, 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 meet its potential and to take action in a method that makes very environment friendly use of spectrum, a scarce and helpful neighborhood useful resource. Wi-Fi’s spectrum effectivity is definitely demonstrated by observing that present use patterns present that Wi-Fi networks carry about twenty instances extra knowledge 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 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 methods solely use a small subset of Wi-Fi’s numerous and complex sharing mechanisms, with early deployment measurements exhibiting poor coexistence with Wi-Fi methods (and doubtless between LAA/NR-U methods too). The possible poor coexistence of those mobile applied sciences with Wi-Fi can be a significant financial (and social) drawback, given Wi-Fi’s significance to customers and companies and its multi-trillion-dollar world financial worth … yearly!
There could also be nothing to fret about if LAA and NR‑U usually are not extensively deployed, which is a definite risk. If they’re extensively deployed, vital effort might be required to mitigate the potential opposed influence on Wi-Fi’s environment friendly and shared use of unlicensed spectrum in the present day. 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 completely different applied sciences can extra simply keep away from working in the identical channel. A greater general answer to maximise shopper profit is to concentrate on 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 free of charge!
As regulators seek for probably 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, notably within the 6 GHz band.
Key messages
There are a key few messages that I would love 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 (normally utilizing Wi-Fi know-how) is probably the most environment friendly method of assembly consumer’s wants in most environments (notably residence and enterprise), however licensed spectrum (utilizing mobile know-how) can also be essential 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 total 1200 MHz of the 6 GHz band is urgently required in order that Wi-Fi can proceed to distribute the entire knowledge delivered to end-users and allow new purposes together with Digital Actuality and automation.
- Deal with Wi-Fi: Whereas any know-how is allowed to make use of unlicensed spectrum, a concentrate on Wi-Fi is fascinating to keep away from coexistence points that may come up from the usage of unsophisticated sharing mechanisms by applied sciences like LAA and NR-U.
In the event you purchase into my conclusions then I recommend 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 happy 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, sophisticated & monopolized
One doesn’t must go very far again in historical past to a time when most technique of communication throughout any distance have been costly, sophisticated, and relied on providers 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 toddler (OK, it was half a century in the past), the place we needed to ebook 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 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 practical
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 knowledge communications (together with POTS-like, e-mail, and Webex-like providers) throughout the globe to nearly zero. For many individuals, the prices are zero, offset towards 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 would possibly disagree. The truth is that the providers themselves are much less complicated, however the selections they supply have massively expanded, typically making every little thing appear extra sophisticated. They’re definitely extra practical.
Whereas conventional service suppliers nonetheless dominate the supply of facilities-based mobile providers, they face much more competitors within the provision of broadband providers to customers 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 increased up the worth chain.
Unlicensed spectrum is a key driver of the trendy communications
There are various 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 significant 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 necessary. 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 might recall the times when establishing residence 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 residence or workplace that simply labored, utilizing a tremendous and nonetheless rising number of gadgets & purposes. The FCC experiment was so profitable that it has now unfold globally, additionally increasing into elements of the 5 GHz band and (hopefully) all of the 6 GHz band.
Wi-Fi is probably the most profitable know-how in unlicensed spectrum
The success of Wi-Fi could be measured in numerous 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, more likely 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 favored 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 folks would reasonably 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 instances extra knowledge site visitors in the present day goes throughout Wi-Fi networks in comparison with conventional cellular-based networks, which themselves are a significant 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 varied 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 large success highlights a captivating query. Why does the usage of a number of applied sciences (together with Wi-Fi) managed by a large number of unmanaged customers working in the identical spectrum not lead to coexistence chaos? There are three most important solutions from a historic perspective:
- Completely different channels: Wi-Fi typically 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 same old Wi-Fi channels
- Numerous sharing mechanisms: Wi-Fi features a range of sharing mechanisms (e.g., Hear Earlier than Discuss, exponential back-off, Preamble Detection, NAV, RTS/CTS, and many others) 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 trade 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 isn’t a excellent answer to deal with this very troublesome drawback. Wi-Fi’s technical answer is to make use of a range of sharing mechanisms (as famous above), constructed on prime 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 discuss 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 might trigger interference. Utilizing the dinner desk analogy once more, the folks 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 drawback).
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 gadgets at a really low power stage when it’s positive the power comes from one other Wi-Fi machine, by detecting a particular Wi-Fi packet preamble. This is called Preamble Detection and Wi-Fi usually 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 additionally 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 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 thought is that if one other machine is transmitting (or one other particular person 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 special method … they only shout louder).
However there’s extra. Wi-Fi additionally permits reserving the channel for restricted intervals utilizing a particular subject that’s included in Wi-Fi packets (the particular subject is named 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 permits 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 folks 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 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 out there 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. Nevertheless, unlicensed spectrum (particularly the 5 GHz & 6 GHz bands) is commonly 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.
Nevertheless, many mobile stakeholders have now determined that entry to unlicensed 5 GHz & 6 GHz bands is a chance too helpful (or too low-cost) to depart 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 usually utilizing Wi-Fi offload to supply providers in indoor places usually 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 as a substitute, regardless of Wi-Fi largely 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 best way they do for mobile applied sciences. In current 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 lots of the claims have confirmed to be extra hype reasonably than actuality.
The primary two applied sciences are not being promoted by the mobile trade 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 argument that arose as a result of LTE‑U was primarily based on a really unusual method of sharing with different applied sciences. Reasonably 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 more moderen years, 3GPP has permitted 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, identical 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 methods. 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 methods use an EDCA-based model of LBT with exponential back-off and the identical timing parameters. Nevertheless, LAA and NR‑U solely pay attention for different methods 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 helpful 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 basic adjustments 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 objective of the mobile neighborhood defining a substitute for 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.
Intensive simulations over a few years in 3GPP and different boards instructed that LAA and NR‑U methods utilizing only a subset of Wi-Fi’s numerous sharing mechanisms would coexist pretty with Wi-Fi methods, not less than within the common case. The large query is does this declare maintain up in actual deployments in unlicensed spectrum, which regularly usually are not 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, is just not 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 to date recommend 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 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 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 recommend 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) methods to adversely (and considerably unreasonably) influence Wi-Fi operations:
- Whereas Wi-Fi methods usually defer at power ranges of -82 dBm (utilizing preamble detection), LAA methods solely defer at power ranges above -72 dBm
- Whereas Wi-Fi methods have hidden station mitigation mechanisms primarily based 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 unbiased analysis can also be wanted. Nevertheless, for my part, the outcomes are more likely to be broadly right as a result of they are often simply defined.
Making ready for poor coexistence points
Poor coexistence between LAA/NR‑U & Wi-Fi is just a difficulty if LAA/NR‑U are deployed at scale however trade must be prepared for this risk.
The poor coexistence between LAA & Wi-Fi highlighted by the College of Chicago’s research is fascinating from an educational perspective. Nevertheless, they’re solely necessary 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. Information 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 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 is just not 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 need to adversely influence 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 presently many uncertainties and unknowns. There’s nonetheless an actual risk 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 is important 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 thinking about 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 supplies the most effective 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 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 technology of Wi-Fi as IEEE 802.11be, which is able to 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 technology, 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 enough to supply good (albeit not excellent) coexistence between unbiased methods in unlicensed spectrum.
- In distinction, it’s no shock that the one-dimensional power detection targeted sharing mechanism utilized by LAA and by NR‑U is insufficient.
The higher answer is to concentrate on Wi-Fi as the principle WLAN know-how in unlicensed spectrum as a result of it has been confirmed to supply a wonderful stability between efficiency, prices, and coexistence, permitting anybody, wherever, anyplace to arrange a community that simply works! After all, 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 in the present day 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, in fact, be some overlap between these use circumstances. Reasonably than worrying about coexistence on the PHY stage, this idea simply requires everybody to concentrate on integrating 5G/6G options with Wi-Fi additional up the community stack, with the last word purpose of offering the identical excessive efficiency to customers irrespective 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 might be identical to licensed spectrum for these applied sciences) or by Wi-Fi (domestically licensed spectrum might be identical 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 knowledge site visitors in an economical and environment friendly method
A coexistence answer primarily based on an acceptance that Wi-Fi is the first know-how in unlicensed spectrum leads us straight into one other modern 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 elements 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 can be a response to the fact that Wi-Fi site visitors is doubling each 3 years, and the present 2.4 GHz and 5 GHz bands are rapidly changing into congested. As new data-intensive purposes 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 sturdy 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 may in all probability not be resolved till the ITU-R WRC-2023 convention on the finish of 2023.
The controversy in regards to the allocation of the higher 6 GHz band is multi-dimensional, with a number of handwaving and self-serving arguments, usually primarily based on unsupported and really enthusiastic assumptions. Each side of the controversy assert that extra spectrum is required to assist rising consumer wants for extra knowledge. 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 price). Apparently, 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, wherever, 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).
Reasonably 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 premise {that a} decision of this debate within the context of Europe can have a big influence globally:
- Applied sciences, like 4G/5G/6G, that use licensed spectrum have entry to only 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 knowledge from the German Ministry for Financial Affairs & Local weather) the huge bulk of knowledge in the present day is transmitted over Wi-Fi
- Cell networks in Germany in 2021: 4 Exa Bytes (5%)
- Mounted 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 display that unlicensed spectrum, utilizing applied sciences like Wi-Fi, satisfies the wants of most customers in the present day, in a fashion that’s considerably extra environment friendly (as much as 20 instances extra environment friendly) and versatile than licensed spectrum. It usually does so at a a lot decrease price to the consumer. It’s not troublesome to additionally conclude that the advantage of 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 capable of assist customers’ wants by making the entire 6 GHz bands unlicensed. Nevertheless, possibly their actual purpose has nothing to do with satisfying customers’ wants however as a substitute 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 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 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 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 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 need to meet customers’ wants whereas making environment friendly use of spectrum
- Unlicensed spectrum (normally utilizing Wi-Fi know-how) is probably the most environment friendly method of assembly consumer’s wants in most environments (notably residence and enterprise), however licensed spectrum (utilizing mobile know-how) can also be essential 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 total 1200 MHz of the 6 GHz band is urgently required in order that Wi-Fi can proceed to distribute the entire knowledge 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 concentrate on Wi-Fi is fascinating to keep away from coexistence points that may come up from the usage of unsophisticated sharing mechanisms by applied sciences like LAA and NR-U.
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