Massive MIMO for 5G: How Big Can it Get?

[@VikrantSingh-se2zb]

Thanks for caring to share your technical expertise on future of wireless communication channels.

[@fahimehjabbarinia401]

Awsome Dr.Bjornson .thank you

[@wafaelhajhmida3863]

thank you for this presentation, very brillant as usual ! Could you plz explain to me for min 13:24 for maximum ratio filter for V1 why did you normalize h by M? as much as I know for MRC v1=constant* h. why do you choose a constant equal to 1/M?

[@WirelessFuture]

Yes, any constant would be ok. The normalization with M is selected to apply the law of large numbers in a clean way. Moreover, if you pick any other constant, your receiver algorithm will eventually divide by something that gives you roughly 1 in front of the signal, so even if people like to write maximum ratio without a constant, it is needed in practice. Just to get the constellation points at the right places.

[@wafaelhajhmida3863]

@@WirelessFuture thanks for these clarifications!

[@CuongPhamQ]

In 18:52, the number of antennas is just 8 elements *4 panels =32 antennas/sector --> please re-check it again

[@WirelessFuture]

As said at 18:52, each panel contains 8 dual polarized antennas, which means 16 antennas. 4 panels of that kind becomes 64 antennas.

[@isabellamedeiros8688]

That's such a great explication, amazing, thanks a lot!

[@mangaldeepsahoo7078]

My all time favorite Lecture on 5G.. One Request, for Uploading Video on 5G Physical Layer and Cell Search Procedure.

[@atchutram9894]

Dear Mangaldeep, the Speaker is a renowned academician pioneering massive MIMO research. Academia usually focuses on data plane and it is very unusual to study control plane and standard details. Moreover, as far as I know, 5g standards are not that matured yet. If you want to learn about cell search and other physical layer concepts, I recommend 3GPP TS 38.213

[@arsulaksono881]

fantastic presentation to update my knowledge about 5G

[@ehabali7237]

awesome and simple explanation from the Speaker

[@mustang6212]

Very good presentation about a so hot topic which is Massive MIMO thank you so much.

[@luannaabreu731]

Hello Sir, According to the definition of the concept of ERB coverage area (gNodeB) when using narrow beam pointing generated by MIMO antenna in beamforming (BF) mode: Pointing a narrow beam covers, at maximum gain (up to 3 dB below), a relatively small area around the UE reference point (or UE cluster). How, therefore, is the concept of the coverage area of an ERB, and its correlate, the percentage of coverage area (a statistical parameter that considers the effect of log-normal multipath shading and weights its effects in an area around the ERB)? When considering the multi-user MIMO mode, with multiple narrow beams... The coverage area of an ERB would be defined considering all the beams pointed at different points in the surrounding area, or for each beam, is an area or sub-area of coverage defined? In the previous question, the starting point of view was what happens in the vertical plane that contains the ERB and UE antennas. There is also a concern with what happens in the signal distribution in the horizontal plane. In previous generations, a fundamental related concept is the division of the coverage area by sectors, something that was directly related to the beam width of the ERB antennas. For example, using 120º beam antennas, 3 antennas covered the 360º that would characterize the entire area. With multiple beams, one can imagine maintaining this concept and expanding the number of sectors. For example, with widths of 10 degrees per beam, horizontally, 36 would be needed to cover the entire area. From the above, I ask: the concept of the coverage sector remains in 5G, adapted to the multiple beams of the antennas MIMO? Given the considerable (apparently) change in planning: do the concepts of coverage area and percentage of coverage area remain essential for planning? What other related concepts came to be used? On 4G, are they already used? Given the complexity of using and coordinating multiple beams: in which scenarios and application conditions, will the MIMO strategy with multiple beams be used? The macro scenario is extreme broadband, communication ultra-reliable, or massive communication for multiple users? Is the environment outdoors, indoors, or both? Is the band sub-6 GHz or millimeter wave? Still on the previous question, in the scenarios foreseen for using MIMO with multiple beams, another question arises. In which of these beamforming scenarios will be “fixed” and in which will it be adaptive (following cluster of users, with or without the interposition of nulls of the radiation pattern in the directions of other groups considered interference for that cluster)? Finally, considering all the different aspects of previous generations brought by the multi-user (multibeam) MIMO approach of 5G discussed here…. How has the link budget analysis been (or needs to be) adapted to address these aspects? Best Regards!

[@AnilBhandari01]

Fantastic lecture. It seems that operators should opt for massive MIMO panels depending on subscriber density e.g. In a network with higher number of concurrent users, a panel with high number of elements would be appropriate. However, the same panel if used in an environment with low number of subscribers will give lower SE.

[@archaeologytomtex]

Hello professor Emil Björnson. In one slide you mentioned with more antennas in an array, the beam can be as sharp as laser, which can aggregate the most energy to the desire and reduce the most interference to the unwanted users. I'm wondering if you distribute the antennas in the cell-free case, as the antennas are not half-wave length separated, how could the antennas steer to a sharp beam to avoid high inter-user-interference physically?

[@WirelessFuture]

tomtexblack Here is a blog post where this is explained: ma-mimo.ellintech.se/2019/01/25/beamforming-from-distributed-arrays/ Please feel free to ask follow up questions on the blog!

[@sunilareddy8191]

excellent work

[@1754sivarao]

Simply Superb.Fantatastic explanation

[@nabilakdim2767]

Fantastic talk as usual, thanks Emil

[@tb9734]

Antennas for everyone. Lots of antennas. There is no escape, lol.

[@sandeepreddy8567]

13:04 how does the base station know the channel h1 ?

[@WirelessFuture]

The easiest way to learn the channel is to let the user send a known signal so that the base station observes h1 + noise.

[@ietlamvan8336]

so good lecture!

[@kozhenidres314]

thank you it's so useful and we described , do we need tens or hundreds of antenna for OFDM and OFDMA since both divides bandwidth to smaller sub carriers or we just use large number of antenna for massive MIMO and beam forming ?

[@WirelessFuture]

Only a single antenna is needed to use OFDM or OFDMA. However, instead of serving one user per subcarrier as in OFDMA, multiple antennas (Massive MIMO) can be used to serve multiple users on each subcarrier.

[@saraswathimani9411]

Very useful lecture. Thank you.

[@asifalamjoy9530]

Are there any ways of eliminating pilot contamination?

[@WirelessFuture]

Yes, there are many ways to deal with it. The most powerful method is to utilize spatial channel correlation, as explained in this video: kzbin.info/www/bejne/hZy3eaaKfbWHh6M

[@waelmm9143]

Pls could you help me in simulation of the channel in lte underlay d2d wireless communication

[@salimaesslama1324]

is MIMO necessary for 5G or there is other technologie ?

[@WirelessFuture]

It is not necessary. 5G is a mix of many techniques. But the first phase of 5G deployments has almost exclusively made use of Massive MIMO in the 3 GHz band.

[@salimaesslama1324]

@@WirelessFuture thank you very much

[@kavyapise8812]

Good information sir.....please do attach the respective paper and slides

[@WirelessFuture]

You can find a lot of papers and slides at ebjornson.com/research/

[@mulusewyitbarek5635]

what is the diffrence between single cell massive mimo and multi cell massive mimo

[@WirelessFuture]

mulusew yitbarek A single cell consists of one base station and the users that it communicates with. If more than one such cell is located next to each other, it is called a multi cell system.

[@mulusewyitbarek5635]

ok thank you for your answer .would you mind give me Msc title on massive mimo?

[@mulusewyitbarek5635]

would mind tell me books on channel estimation techniques in massive mimo system

[@WirelessFuture]

mulusew yitbarek Chapter 3 in the book Massive MIMO networks deal with that in detail. You can download it from massivemimobook.com

[@pedrovieira9339]

Excelente apresentação

[@RenoBlade2]

Hi, what will happen when we have 200 Antenna and 800 User? In your Video you speak always that we have more Antenna than user. Can 2 or 3 user share one beam in beamforming? Thx for your answer.

[@WirelessFuture]

Eduard Walz, one can have more beams than antennas or let multiple user use the same beam, but it won’t improve the performance. It is better to let the users take turns, using scheduling. The highest data throughout is typically achieved when you serve fewer users than the number of antennas. With 200 antennas, 100-150 users is probably the preferred range.

[@RenoBlade2]

Communication Systems, Linköping University, LIU Will I lose the MiMo gain and the beamforming?

[@WirelessFuture]

The MIMO gain will still be there, but the inter-user interference will be too large for the system to work efficiently.

[@engmoh1115]

it is great , i am working on it now ,. may i get his email pls because i need some help from him ? thanks

[@WirelessFuture]

You can find Emil Björnson's website and email address if you search for his name on Google. He is the only one with this name.

[@saeedibrahim996]

great job it's perfect idea of massive MIMO ,, now I'm in China working on it ,, i wish if I can have your email please

[@WirelessFuture]

saeed ibrahim You can find the speaker’s contact information here: liu.se/en/employee/emibj29

[@saeedibrahim996]

thanks

[@neilthecaptain1134]

all of us in Devon and Cornwall, are just fine with 3,g,we will keep that,we dont want anymre antenna thanks anyway.

[@WirelessFuture]

The Massive MIMO technology will, of course, only be deployed where there is a demand for better cellular networks.