Basics of Antennas and Beamforming
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- Опубліковано 5 лют 2025
- The author Emil Björnson of the book "Massive MIMO Networks" explains and visualizes the basics of antennas, radiating elements, and beamforming in multiple antenna communications. Mathematical details are available in the book, which can be freely downloaded from: massivemimoboo...
![Three Benefits of Using Multiple Antennas in Communications [Video 2]](http://i.ytimg.com/vi/tw0yD65viVI/mqdefault.jpg)
![Three Benefits of Using Multiple Antennas in Communications [Video 2]](/img/tr.png)
I've been looking for more details on Beamforming and Massive MIMO for a few days now. Hours of reading and researching condensed into less than 8 minutes! Fantastic
Thanks a lot for this video :)
I'm a graduate researcher working on Massive MIMO, however I do not have antenna background. I am interested in signal processing parts of Massive MIMO. When I watched this video I really understood beamforming concept. Thank you for this simple yet elegant explanation.
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Finally someone properly explaining how the beamforming thing works! Thank you.
Wow... UA-cam's algorithms let me 'stumble' upon your video... Well done and thank you for the PDF!
I had zero knowledge about antenna and I found your tutorial super useful and understandable. well done and thanks a lot!
Thank you so much Sir. for your great way of explanation of this concept and also for the free PDF book download.
Thanks for making the pdf book free of charge
Best explanation i had seen so far, greetings and big thanks for sharing
Very clear explanations. Great ! Thank you for it.
Daniel Ichbiah (from France) :)
PS: I'm the author many books on technology which makes me particularly appreciate your approach.
Thank you for sharing this knowledge for free. It is amazing.
Very clear delivery of content, thank you. Please make more videos.
Great video. Very clear and covers broad issues. Would like to see more
Thanks alot for this! Most videos over simplify the concept... I understand that my 450m can talk to multiple subscribers... now I understand what's going on inside it a little better.
best 7 minutes among the hours studying 5G, thank you
simple explanation of diff between hybrid and phased beam forming. thanks
Thanks for this video. Very good explanation, easy to understand.
Excellent explanation! Many thanks.
讲的通俗易懂，点赞！
great video. Helped me understand array antennas
Simple explanation .. graphs and example are great . Thanks for sharing looking more videos
Simply Great Video. Understood in simple words. Thanks for sharing knowledge.. :-)
Great video. Super helpful! Thank you.
Very intuitive explanation, thank you Professor
Excellent video, thank you so much for your free PDF!
Nice explanation. Thanks
Thank you very much for this video.
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 beamwidth 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!
Incredible information. Thank you
Thank you for share your knowledge
Wonderful, very informative
Great video and thank you for the free book!
Thank you for this video
simple and clear explanation
I agree with you Dr.
Thanks for the video and PDF file.
Awesome explanation
That's a good explanation
This is what i was looking for. Thank you
What is never mentioned in antenna radiation is whether or not the E/M loops being radiated do break down into loops of half wavelength as the loop try to grow in size with distance, In waveguides and cavity resonators it is common to show the stacking of " half wavelength E/M blocks to fit in the available space. A one megacycle wave, has a much larger loop than a 5 GigaHertz signal and though everyone talks about lobes, and directivity, and efficiency, and so on, no one talks about the "stacking of E/M blocks" the size of which depends on the frequency of transmission. So for a given frequency , how many stacked E/M loops exist in it as the wave moves out? I have thought about this for the last 80 years and it seems to me that when one has a directional antenna, or a phased array, all that is happening the system is cutting off and eliminating the peripheral blocks in the stack of E/M blocks in the lobe or in any omnidirectional antenna,
I simulated this with a computer algorithm which, when the circumference ( wavefront) of the wave grew larger than a wavelength integers, then the " circumference would accommodate another loop half a wavelength long".
The simulation works beautifully and the patterns that emerge make it so obvious, after I saw it, From a central location of the antenna, after the wave settles down, the patterns seems to change from a "polar diagram" to a cartesian diagram where the four symmetrical squares of cartesian coordinates, simultaneously move out their four quarters containing the same pattern of E/M loops as exist in rectangular waveguides contain the higher modes. When I plotted the B and the E field loops far from the antenna they came out to be exactly as occurs in rectangular waveguides with the B loops as normal, and the E loops are exactly the same as the E in the waveguide and the surface currents in a waveguide, It is exactly the same pattern,
So it seems, that a centrally placed antenna as a source, will have the near E/M fields going through "a pushy transient pattern" then "a middle field pattern" which I call the settling down zone, and then the far field would resemble the pattern obtained in a rectangular waveguide excited with an electric probe or a magnetic probe as one desires. It is fascination to see the four quarters of cartesian coordinates moving out with additional loops being added as the distance increases, It is remarkable,
This stacking of E/M blocks, the size of half a wavelength, in a radiating pattern, is interesting, and in a phased array or a directional antenna, it seems that all one does is to " phase out the peripheral E/M blocks and donate the power to the other half wavelength E/M blocks remaining in the " stacked lobe" There seems to be more going on in radiation than one thinks, and this "stacking effect" needs further discussion . An analogy may be used by looking at Chladni's figures in vibrating sheets or a Jelly block, and after all our radiating medium is not much different from a jelly or a rubber block with its "own impedance" in how it permits our signals to "accelerate " build and decay and reverse those the E/M loops the size of half a wavelength.ua-cam.com/video/wvJAgrUBF4w/v-deo.html
Thank you and great explanation! This topic is beautiful.
thank you! you are a nice man. It helps me a lot.
I wish you were my professor at the university
thank you emil
I really enjoyed, thanks a lot for your great explanation. I am eager for purseuing my PhD under your supervision if possible.
Very nice explanation sir
Very informative; thank you!
Hi Emil,it was so absorbing.Would like to know how digital tilt works,example 4 digital tilt means what and if we are doing 4Electrical and 4 digital would it mean 8 digital tilt in all
I guess that you with 4 and 8 are referring to degrees? You want to tilt the direction of the transmission by 4-8 degrees compared to the broadside direction? The main concepts are normally electrical and mechanical tilt, where the former mean phase-shifting the antenna inputs and the latter means deploying the antenna array with a physical rotation. Cellular base station antennas are often deployed with a few degrees of mechanical tilt towards the ground and can then use electrical tilt (beamforming) to direct the transmission further towards the ground.
I haven't heard talking about digital tilt, but I believe it is the same as electrical tilt. One could certainly distinguish between how the electrical tilt is generated: phase-shifting in the analog domain or in the digital domain.
@Wireless Future HI Emil,My question was AIR3419 or AIR3458 has both Digital and RET configured,so we set 4 as digital tilt and 4 as RET in AIR3458 so now the combined tilt will be considered as 8 degree tilt or it will 4 degree ,
Thank you, dear professor!
How can I express about the sidelobe level in antenna array mathematically as an equation?
Excellent explanation. You make it sound so interesting and simple👍🏿👍🏿👍🏿
So does this mean I can make my own ILS transmitter and receiver!
That would be interesting just from a I just must know it kind of an approach.
Have no dots connected yet 😎
Excellent, Sir
What's the shape of the antenna that you're assuming here though?! If a rod for example, then which way is it placed relative to your schematics?
You are right that we abstracted away the exact antenna design. I think the illustrations are mostly applicable to patch and aperture antennas.
@@WirelessFuture Thank you for the clarification.
great explanation, what about at home (house) with walls and floor levels (2 levels), do you need multiple antennas or just one (omni directional) ?
If you get a WiFi router with 4 antennas, you will get a roughly 4 times stronger signal everywhere in the home. That might make a big difference if there are places in your home where you currently have poor coverage (few bars). However, if you already have good coverage everywhere in your home, the difference will not be noticeable. The signal strength is typically varying by 100000 times within a house (from being close to the router to far away), so an extra factor 4 is not always noticeable...
@@WirelessFuture how about the direction of the beam ? I believe it is directional.. I believe you need to spread it evenly , factoring also the refections for indirect areas / behind the walls ...
@@arsulaksono881 The beam will be directional and change depending on who is using the WiFi at a given millisecond and where the person is in the house. So the signal will not be stronger everywhere at the same time, only stronger where it needs to be stronger
Dette var interessant
Thankyou verymuch.
Nice video, really helpful, I have a question though... what tool do you guys used to draw schemes in latex
abraham ka: The illustrations are made with a combination of Matlab (to get the right forms of the beams) and Adobe Illustrator.
If you go the multiple transceiver approach can you in software read many different sources at once by by computing the beams they would have come in at after the fact?
zyxwvutsrqponmlkh Yes, you can receive signals from multiple sources and then transmit back to multiple sources at the same time.
What do we call a receiver array which ISN'T trying to "point" in any direction. Instead, a smart back end listens to all the elements in the array, and decides, based on detected signal, which ones to sum, which ones to invert or phase-shift, and which ones to ignore?
An analog phased-array is physically pointing in one direction, while a digital antenna array can receive from any directions - it decides afterwards in the digital receiver processing. This is just called digital receive beamforming/combining.
If you pick a subset of the antennas to use, it is called antenna selection.
@@WirelessFuture Thank you!
Thank you for your amazing vidio. But I still have a question. Why we use SINR to evaluate the system performance instead of SNR. As you mentioned the power is focus on the directoins what we need. This is really confusing...
The received signal power should be compared against all the disturbances that exist, including noise and interference. The SINR gives that comparison. If there is only noise and no interference, then SINR = SNR and we can talk only about the SNR.
@@WirelessFuture thank you very much! :)
Nice explanation
this makes sense, however it wont work if you connect the antennas together, you need an expensive piece of equipment to manage the array! Please could you talk about the point you plug all of the antennas into and you cant splice mutiple antennas as this will share the power and change the freq
In digital beamforming, you plug all the antennas to the same baseband computer, so the beamforming is done in the memory of that computer where you set the power and phase for each antenna. One can also build phased arrays where the baseband only generates one radio signal, which is then divided into multiple antenna branches and phase shifted by creating delays. This is standard technology these days. Every 5G phone uses 4 antennas with digital beamforming.
Thanks for the description.
very good explanation. learned more than a masters degree level course.
thank you so much Dr for your explanation of this concept . Dear Dr. is it possible to compare SE of pilot based,blind ,and semi blind channel estmion for uplink massive MIMO? if it possible how?
Yes, it is possible to compare these things. You need to choose one algorithm of each kind and implement them in the same simulation environment, and then measure the SE.
ok, svd for blind and semi blind and MMSE for pilot, is there simlar SE formula for those algorithm?
Very good
Thank you for this informative video! I am still not sure what the difference between phase array beam forming (talked about towards the end of the video) and MIMO beam forming is exactly. You said they both are formed using phase differences so I am still not quite sure where the difference begins? (You said separate signals for MIMO but what does that mean exactly?) Thanks!
With a phased-array beamforming/beamsteering, you can only transmit one beam in one angular direction at a time. With MIMO beamforming, you can transmit a summation of many beams. These can be directed towards different objects in the propagation environment, so that the user receives the signal from multiple strong paths. They can also be directed towards different users, so the users don’t have to take turns but can all be active at the same time.
@@WirelessFuture ahh.....very deep....got it.
nice and to the point!
really nice and helpful. Just a query - 64 Antenna system called 64*64 Massive MIMO ?
The industry likes to call it 64T64R. This means that there are 64 transmit antennas and 64 receive antennas at the base station. It might seem obvious that there should be the same number of antennas for reception and transmission, but this is not always the same. Many LTE phones have two receive antennas but only one transmit antenna.
@@WirelessFuture Thank you for clarification and prompt response
what about distance between two radiation elements ?
The general guideline is that elements should be spaced apart by half a wavelength. Shorter spacings lead to mutual coupling. Larger distances are possible but require a larger form factor of the array. It makes the main lobe narrower but at the expense of creating ”grating lobes” pointing in undesired directions.
Wouldn't this allow for a functional security method through beam forming and frequency modulation?
I'm not sure what you mean with "functional security method".
My Understanding is currently when operating at high frequency, we use the analog beamforming which consisting to send the same signal over many antenna elements but with phase shifted which is the phased array. I'm wondering as in this case we have only one "LAYER" (Rank indicator is always one = one signal) is there any precoding matrix or codebook index in this case 🤔
Thx so much sir, great video.
Here some mistakes.The Angle is not clear.It maybe a angle between antennas axis and the wave.I can't understand whether it's a 2D or 3D image.
Figure 1.10
@@leeyifeng1989 If you have a ULA in one location and a single antenna device elsewhere, they exist in a 2D plane of our 3D world. The simplest way to view it is to say that the ULA is deployed on the ground and that the user device is also on the ground. The angle phi is then the azimuth angle in the ground plane.
Is the Antenna we See in the Video not an MU Mimo Antenna and not an Massive MiMo Antenna. When the Antenna covers an distance 300m there shoud be more User than Antenna Elements.
If we are using 2×2 MIMO used then both will be same frequency band or we need different frequency band to perform 2x2 mimo??
2x2 MIMO means that one can transmit two streams of data in the same frequency band at the same time. This is achieved by spatial multiplexing.
😍😍😍😍😍
thank you alot
i cant stop seeing ur eyes moving to the left, but thanks for video, really helpful
paying attention to such minute details😂...awesome...you should be a detective
Hi! I have a question. It is said that phased array antennas steer the beam for transmission. But, what about reception? Is the reception pattern also steered?
Yes, it works the same. During reception, signals from different directions are amplified differently to create a directional reception pattern.
Excellent explanation , can you help me to explain non linear beamforming techniques and any matrial for that
Thank you!
thank you for free pdf of your book.
Thank you for the PDF.
Thank you for your presentation. Would like to say something about performance analysis of channel estimation techniques for massive mimo.
This is covered in Chapter 3 of the book Massive MIMO networks.
there is pilot contamination in uplink channel estimation ,so to mitgate interferance we need to now data aided channel estimation .would like to say something about the data aided algorithm in semi blind channel estimation also include the matlab code?
mulusew yitbarek Data-aided channel estimation can help to mitigate pilot contamination, but it is not necessary. As explained in Chapters 3 and 4 in the book, pilot contamination can be effectively mitigated in the spatial domain, by using MMSE estimation and M-MMSE processing.
have you video on spatial domain MMSE estimation and M-MMSE processing.
I wish you had online courses!
sir, in mobile communication system, when multiple users are present in a cell, how many beams can a base station send? In smart antennas, will each antenna send a separate beam for each user? Kindly explain
The beams are created by sending the same signal from all antennas with different delays. One can transmit arbitrarily many beams from an array, but since the power will be divided between them and the beams have a non-zero width, you don’t want to send more beams than there are antennas.
@@WirelessFuture Sir, so all of the antennas will be receiving signals from different users and generate beams in each direction? like one antenna will receive signals from multiple users.. Can you please tell me what are the "weights" used in smart antennas for beamforming as in an adaptive array antenna. thank you so much for answering my query
@@ridazafar1798 All the antennas are receiving a combination of different signals with different time delays, which manifest themselves as phase shifts. To extract the signal from one user, the weights are selected to "invert" the phase shifts so that all the desired signals are added up in phase. We have video series on "Introduction to Multiple Antenna Communications" and "TSKS14 Multiple Antenna Communications" that go through these things in detail.
@@WirelessFuture thank you so much for clearing this point .
I'll definitely watch those video
sir, out of channel correlated and channel uncorrelated , which is better in LOS and Rayleigh
Practical channels are always correlated, in both LOS and non-LOS (such as Rayleigh fading).
Hi emil thank you so much for this video!! I just want to confirm something if i want to have 4x4 mimo to one user can i have this capability with one beam?? Or i need 4 beams to have 4 layers sent to the user??
Kinan Alkhouri You can only send one layer per beam. So you need to have 4 beams to send 4 layers.
Thank you a lot good description
Gracias
Thanks Sir
what is the significance of rician factor
kiran patrudu This is not covered in this video, but you can read about it here: en.m.wikipedia.org/wiki/Rician_fading
gr8 explanation
Why most of the time we use pilot based channel estimation techniques for Massive MIMO? Your book also use pilot based channel estimation. Why not we use blind and semi blind channel estimation techniques?
Blind and semi-blind methods are discussed in Section 3.5 of the book. However, the rest of the book considers pilot-based channel estimation since (a) it is normally what is used in practical systems, (b) the theory is well understood, (c) it is sufficient do deal with pilot contamination as seen in the asymptotic analysis in Chapter 4.
Dear Dr.,Ok sorry i will correct it in more respect way
Dear. Dr Bjornson. Would you mind help on matlab code for pilot based, blind and semi blind channel estimation for massive mimo systems. I konw from previous answer pilot based is preferred how can we compares in simulation rather than theoretical. In your book only pilot based matlab code is available,matlab code for blind & semi blind is not aavailable.
mulusew yitbarek You are right, only pilot-based channel estimation is considered in the book. So there is no Matlab code available for other methods.
Thank you Sir
Thank you
Dear Dr. Would mind help me on, how channel estimation in massive MIMO increase EE.in your book massive MIMO SE&EE .there is no simulation graph how channel estimation in massive MIMO to increase EE. Only you show the formula for Ls, MMSE and EW-MMSE for intracellular interference. How can i gate those formula &how can i Simulate.
If you run the code for Figure 4.14 or Figure 4.20, you can use those sum SE values and multiply with the bandwidth of 10 MHz to get the sum rate. You can then compute the power consumption using the formulas from Chapte 5 and finally compute the EE has rate / power.
@@WirelessFuture ok thank you Dr. how can we proof EE of mmse,ew-mmse and ls in equation 5.37 in your book
@@mulusewyitbarek5635 Those numbers are taken from Table 3.1 and the number of complex multiplications are quantified using standard linear algebra results in the appendix.
@@WirelessFuture ok thank you Dr. Dear Dr i have another question in your matlab code for example in figure 3.2 when i run the code matlab said that error that is '' undefined function or variable funnctionRlocalscattering'' such type of errors occur in most of the graphs. how can i correct such type of error.? .
Thank you for your help.
mulusew yitbarek That happens if you haven’t put all the files in the same folder.
If the receiving device doesn't have the same beam-forming technologies and multiple antenna's, doesn't it severely undermine the 'advantages' of the tech? eg if the router can transmit a long distance, but the receiving device is too far away to send back an acknowledgement, whats the point?
Und13s Bomber it works even if only the router has multiple antennas. These can be used to improve the range for both transmission and reception. Most user devices only have one antenna.
Excellent
interesting
I don't understand how 2 beams can radiate 2 different signals, isn't it the same radiating system? Aren't the signals being transmitted by both lobes?
foerfoer You create one beam that radiates one signal, another beam that radiates another signal. Then you add the two things together at each of the antennas to create two beams that radiate different signals.