6G in the Upper Mid-Band: The Rise of Gigantic MIMO

[@James_Knott]

As one who studied Electrical Engineering, with a focus on telecommunications systems, along with a long career in telecom, it's nice to see proper technical videos such as this.

[@SoapinTrucker]

So, you like the video, yeah?

[@WVMS42]

Your videos are just amazing. As an engineer, for me it's real brain food. Thank you from Yemen 😊

[@isaunnununu]

Great video! This is a very neat summary of 6G in the Upper Mid-Band. However, to my knowledge, the identified candidate bands for IMT are primarily for 4G/5G, as the ITU-R is still developing and evaluating RITs and SRITs for IMT-2030. By the time a decision is made regarding these bands at WRC-27, IMT-2030 will still be under study. Am I missing something?

[@WirelessFuture]

WRC-27 is the last WRC before the product development and deployment of 6G will begin, so it is the last chance to assign new bands to IMT before that. In principle, any IMT band could be used for 4G, 5G, or 6G. But it is natural that a new generation uses a new band so it will not collide with legacy networks and will have access to substantially more bandwidth. When the ITU has finished the IMT-2030 requirements, there will be a submission period in 2027-2029 for RITs. We describe the timelines for 6G development in 3GPP and ITU in the following video: kzbin.info/www/bejne/bWGlgH53ZbWgmqcsi=kqzkvrVkk9ZlbSBm

[@danielaspin3840]

Good video!

[@jonnalagaddatharunkumar303]

very informative lecture; thank you so much.

[@TheGmr140]

Nice overview 😊

[@geralt_of_rivia-y4s]

Thanks for the insightful video. One of the issue of catering demands is the bandwidth of arrays (operational). What if we have massive bandwidths to operate using the same array (saying a few tens of gigs) ? Theoretically we can get this by connected linear arrays but they are susceptible to high mutual coupling. Why can’t we use connected arrays in base stations?

[@WirelessFuture]

To my understanding, base stations are unlikely to have contiguous bandwidths that are larger than the operational bandwidth of an array. The problem rather arises due to carrier aggregation of multiple bands that are too far apart to use the same array. The industry has started to make products with so-called "interleaved arrays" where arrays for low and mid bands are integrated into the same box. As you pointed out, their design is intricate due to mutual coupling and other non-ideal electromagnetic effects, but it can apparently be done. Ericsson mentions one of its products on this page: www.ericsson.com/en/portfolio/networks/ericsson-radio-system/antenna-system/antenna/passive-antenna

[@jorgesanchez3244]

@@WirelessFuture In the USA, the 6705 Ericsson radio is used for the 28 GHz band (considered mmWave), which can use up to 8 continuous 100 MHz carriers. Regarding interleaved arrays, a passive antenna with multiple ports is used, using the 4449 (new version 4490) low band radios and the 8843 (new version 4890 Ericsson) mid band radios. These configurations are widely used, using NR in 850 MHz and LTE in midband. For antennas, many brands are used, such as Commscope, JMA, etc. For C-band (NR), there are other antennas or radios from Ericsson considered, but they depend on which can be used, but there are like 3 options (2 antennas and 1 radio). I hope this helps.

[@pitmaler4439]

In your new book on page 529-530, you write that the term beamforming gain is also called aperture gain. In the solution of exercise 9.2 c) you write "....The beamforming gain from the reflection is missing in a), but the aperture gain remains." That is contradicting. Thank you. Edit: now I got it, the aperture gain is the gain we get through larger A_eff. Nonerheless, this sentence gives the impression that all these terms are the same.(the sentence on the page change).

[@WirelessFuture]

It is good that you figured it out. Please note that in (9.9), the terms “aperture gain for reception” and “beamforming gain for retransmission” are defined, with “aperture” being preferred for reception and “beamforming” for transmission. Although "aperture gain" and "beamforming gain" are often used interchangeably when considering antenna arrays, Exercise 9.2 adheres to the terminology “aperture gain for reception” and “beamforming gain for retransmission.”

[@brunofelipecosta746]

Thank you for the excellent video. The content was truly insightful. I have a question regarding the MUSIC algorithm example. With the increase of four separated subarrays, the Fraunhofer distance now becomes quite large. Will the same effect be observed in the near-field reactive zone? If so, will the users in that example be positioned within this zone? Thank you in advance for your clarification. Best regards,

[@WirelessFuture]

The reactive near-field zone of an array of half-wavelength-spaced antennas is larger than the reactive near-field of an individual antenna. However, the considered subarrays are far outside each others’ reactive near-field zones so they will not affect each other or grow with the number of subarrays.

[@Manidipa-v9v]

I want to know details about spatial layers and sub antenna array formation. how do these impact the capacity?

[@WirelessFuture]

Spatial layers are data signals sent at the same time and frequency, but with different spatial directivity. It is like listening to two songs at same time - one with each ear. The capacity increases almost proportionally to the number of spatial layers. The word “almost” refers to that we need to divide the signal power between the layers and that there might be interference between the layers. With subarrays, we can reduce the latter losses since the spatial resolution of the transmission improves.

[@TommyB-l3e]

I have a question to an exercise. It is about that capacity expression (OFDM MIMO - 7.10). The solution is C=2S*ld(1+2*q*beta/N0). It is just about the SNR expression. It is surely from the equation...(1+(q_opt*s^2)/N0). The s is 2 for both H (just one sing. value) So 2^2 is 4, but we have 2 in the nominator. I assume q_opt is q/2. But I don't know why? Because we have 2 transmit antennas? But we have just one sing. value, with (7.49), I don't get to q_opt=q/2 with that equation. Thanks a lot.

[@WirelessFuture]

When you compute the frequency response of the channel using (7.45), you get a channel with rank two having two equal-valued singular values. It is then optimal to divide the power equally between them: q_1opt=q_2opt=q/2.

[@iulisloizacarias9737]

Hi! Thanks for the nice explanation! (btw, there is a tiny typo on slide 9 2403 -> 2304 :)

[@WirelessFuture]

Thanks for watching and for noticing the typo!

[@James_Knott]

@@WirelessFuture Why is your reply 5 hours earlier than the post you're replying to? Proactive? 🙂

[@christerwiberg1]

How will power consumption be affected in the carrier network between 5G and 6G, at least estimated? I guess it will increase roughly about the level of bandwidth, is that correct?

[@WirelessFuture]

Yes, the transmit power at base stations is proportional to the bandwidth. The total power consumption also contains digital computations and losses in radio circuits. The latter things can also increase with the bandwidth and/or number of antennas, but are also improved by the gradual hardware improvements that happen all the time. I think the general goal of 6G will be to deliver much more data and better services with roughly the same total power consumption.

[@Henni12-j4w]

Thank you, when changing an equation, we calculate often with matrices and vectors. When I multilply with vector h2, I must then take h2^H because of the dimensions. Is that right h1=.../h2. |*h2 h2^H*h1=..... otherwise it would not fit the dimensions (h1*h2=...). Thank you

[@WirelessFuture]

Yes, h2^H h1 is called the inner product or dot product between two vectors, and it is a measure of how similar they are. I don’t know what equations you are analyzing, but the basic matrix and vector equations for MIMO communications can be found in my open access book: www.nowpublishers.com/article/BookDetails/9781638283140

[@WVMS42]

Do you think that for business considerations they could consider launch the 5.5 G for several years then launch the 6 G ? I'm just thinking from the business prospective side for the major TCOM actors

[@WirelessFuture]

Even if only change the generation number once per decade, there are updated versions (called “releases”) approximately every other year. Sometimes these releases are given new names. You can check the bottom of this Ericsson website: www.ericsson.com/en/5g/5g-for-service-providers/5g-advanced They use the term “5G Basic” for Release 15, “5G Evolution” for Release 16-17, and “5G Advanced” for Release 18 and later. It is 5G Advanced that corresponds to 5.5G, even if they don’t use that specific numbering.

[@hyiux]

In the past each new generation used to bring more bandwidth, more antennas, and more base stations per unit geographical area. 6G seems to continue with the trend of more bandwidth and more antennas but what about network densification? Is their any juice left in that idea or have we pretty much squeezed out every single drop out of that?

[@WirelessFuture]

When there is a need for more capacity, network operators have a choice between adding more base station sites or using a higher MIMO dimension at existing sites. The latter was not a real option until 4G LTE Advanced, and network densification has become less attractive since then. The fact that 5G mmWave networks have failed to become economically sustainable is an example of how further densification is unattractive. So yes, we have squeezed out the most we can from that. What remains is the battle between WiFi and 5G/6G in private networks, where the telecom industry hopes to make money from guaranteeing better performance than in WiFi.

[@hyiux]

@@WirelessFuture Thanks for taking time to answer this. Glad you clarified this aspect.

[@jasminnadic2103]

I am about exercise 6.11 from your great book. Can you give me an approach how we get to that result in a) (P*beta_k/4.....), please? I am struggeling there. Thank you.

[@WirelessFuture]

Thank you for your interest! It comes from the beamforming gain expression in (4.75) with M=4 and \Delta=\lambda/2.

[@WVMS42]

What would be the typical radius of a station in residency areas and for line of sights ?

[@WirelessFuture]

I haven’t seen statistics from which one can deduce a typical radius - I don’t think telecom operators share that data. But it is usually said that the distance between base station sites vary from 500 m in dense urban areas to a few kilometers in suburban areas. The chance of having line of sight reduces with the distance, but it really depends on the propagation environment. Take New York as an example that has long straight roads with tall buildings. You can get line of sight along a road if the base station points in that direction. But can also be close to the base station but around a corner and not have line of sight.

[@WVMS42]

@@WirelessFuture Merci 👍🏻

[@rogerfroud300]

Don't you just love the way they never bother rolling out one generation to everyone before leapfrogging it with another one we don't need yet. Governments should force service providers to guarantee a minimum rollout before they're allowed to even begin rolling out the next one.

[@WirelessFuture]

A cellular generation is first developed under 10 years and then deployed a refined under another 10-15 years. That is why 6G is being developed now even if 5G has only been partially deployed. You are right that many of the new anticipated 5G services remain to be commercialized, particularly those that go beyond “faster speeds” and “capacity for more users”.

[@James_Knott]

It takes many years to roll out a new G, with significantly more advanced tech. Also, you're not forced to drop an existing G and then jump to a new one. My carrier still has 2G and 3G available, in addition to 5G. So not a lot of people are forced to run out and get a new phone. Even when that happens, carriers around here will offer a free replacement, though it won't be the latest and greatest. The older tech will be gradually phased out, until it's time to pull the plug on it.

[@WabuhWabuh]

Over Explained...could have said everything this guy said in 2 sentences... 5G has less bandwidth but more penetrate. 6G more bandwidth but less penetration. Just use 6G for short range data transfer like graphics or low latency transmission...

[@WirelessFuture]

@@WabuhWabuh This is not an accurate summary of the video. Watch the last few minutes if you don’t have the patience to watch the entire thing 😀

[@WabuhWabuh]

@@WirelessFuture it's pretty accurate...tell me what i left out...

[@WirelessFuture]

You leaved everything out, because we didn’t say that the range would be shorter. On the contrary, the video explains how one designs antenna arrays to achieve the same range with much higher capacity. Check the last slide for a brief summary.

[@WabuhWabuh]

@@WirelessFuture Bro you stated nothing important...that's the obvious...anything needs efficient antena array...does not take away from your videos being a waste of time

[@joshuat6124]

I think that's just your opinion/perspective, which of course you are entitled to. Personally, I learnt a lot from the video and how antenna array actually put the wavelength in the denominator.