Thanks for the great video! I was wondering whether NOMA requires synchronization between users? For example, do all users need to transmit at the same time for SIC to work? What if their transmissions are half overlapped?
Why didn't the CDMA prevail in future generation as main multiple access technique ? How can Noma decoding be used at the UE if the strong user doesn't know the channel of the weak user signal ? Wouldn't successive interference cancellation jeopardize the privacy if the weak user ? Why Noma can't add advantage for massive mimo case ? At @14:52 you were talking about considering a line of sight channel as Siso channel but you mentioned that this is unlikely in 5g but I believe with the use of mmwave this is highly likely wouldn't you agree ? Any recommended reference for code domain Noma and how does it work ?
CDMA isn’t providing any extra radio resource dimensions, it just divides them in a different way between the users. OFDM turned out be easier to implement and give more flexibility. In downlink NOMA, a user doesn’t need to know the channel of anyone else since all signals reach the user over the same channel. However, the user must know the modulation and coding scheme of the co-users. Privacy is maintained through cryptography. Wireless is a broadcast medium so anyone can listen and decode signals. Non-linear processing such as NOMA can bring benefits when there are strong interfering signals, but massive MIMO utilizes user-specific beamforming to make sure that there is little interference between the users. It is only a situations where massive MIMO cannot suppress interference well that other methods become useful. This could be a LOS scenario with very closely located users. I recommend the paper that is mentioned in the description of the video.
@@WirelessFuture Thank you for clarifying things up , but in massive mimo we allocate users same time Freq resources and separate them in beam domain By Noma we can add more users to the system by sharing the same beam , wouldn't this be and advantage of Noma in your opinion if combined with massive mimo ?
@@yasserothman4023 The problem is that you need to find users with very similar channels so that they prefer the same beam. This is unlikely to happen, except in the LOS case that I mentioned. The rate splitting framework describes in the paper is at least guaranteed to give better performance than massive MIMO in any situation since it is an add on, but my impression is that the gains are marginal.
@@WirelessFuture I have some questions in rate splitting and I appreciate your feedback , those questions came after reading the paper you mentioned in the video description 1-May I know what does the common message represent in practice , how can we determine its size and content ? 2-How does this scheme (rate splitting) achieve better gains compared to Noma if both depends on successive interference cancellation ?
@@yasserothman4023 1. Section VI in the paper describes that the common message contains a summation of data intended for individual users. It is basically transmitted using TDMA or FDMA, so that each user extracts the part of interest. How to select the right size of the common message depend on the performance metric that you want to maximize. There is a discussion about this at the end of the section, focused on maximizing the multiplexing gain. 2. This is the main topic of the paper, so I cannot repeat it here. The conclusion section provides a summary. “This is due to the fact that the fundamental principle of NOMA consisting in forcing one user in each group to fully decode the messages of other co-scheduled users is an inefficient design in multi-antenna settings.” “Instead, non-orthogonal transmission strategies for multi- antenna settings should be designed such that interference is partially decoded and partially treated as noise based on the rate-splitting (multiple access) literature so as to truly benefit from multi-antenna transmitters (and potentially multi-antenna receivers) and SIC receivers.”
Dear professors, I have questions about NOMA further. what is the control signaling procedure used by NOMA? how do they allocate different frequencies and time slots to send data? I believe the power coefficients are announced by the control signal. I want to know whether NOMA uses ODFM control signaling or a completely different signaling method? Please do answer these questions if possible.
Yes, OFDM is normally supposed to be used and time-frequency blocks can be assigned as in any other system. In addition to normal control signaling, you will also need to inform the involved users of the other users’ coding and modulation schemes and transmit powers, to enable decoding of interfering signals.
Respected sir ,very good video series . Need assistance on following points: 1.How to understand the mathematics behind Massive MIMO and other topics, like what mathematical equation is used for what problem ,how can we judge it. 2. How to implement it with MATLAB? means from model to simulation ? what graphs to be drawn specifically ? What to understand from that graph ? 3.A sample to understand the above two points? As trying to apply Optimization algorithm in MIMO and Massive MIMO , but finding difficulty in implementing it successfully. Shall be highly obliged.
1. We recommend you to read one of our books: "Fundamentals of Massive MIMO" or "Massive MIMO Networks". The latter on is freely available here: massivemimobook.com But apart from the first chapter, it is a more complicated book to read since it uses more realistic models. 2-3. All the simulation code that was used to generate plots in the book Massive MIMO networks are found on its website. This includes solving optimization using CVX+Matlab.
That is an excellent question, which I think the people who still research NOMA should ask themselves because I don’t know. When I cover NOMA in Chapter 6 of ”Multiple Antenna Communications and Reconfigurable Surfaces”, I conclude that: 1) It doesn’t increase the sum rate compared to FDMA, but it allows for dividing that rate between the users in different ways. 2) Large sum rate improvements are provided by MIMO, not NOMA - the added benefits of non-linear processing is particularly small in ”Massive MIMO” scenarios with more antennas at the base station than spatial streams/layers. NOMA can show benefits in papers when compared with some OMA benchmarks (particularly TDMA), but I haven’t seen any examples that are practically convincing. My guess is that many researchers study NOMA because other people recently studied NOMA, in a kind of bad spiral. One NOMA-like method is grant-free multiple access, which can be useful to handle situations with many users devices that want to transmit small amounts of data. The main benefits come from not having to spend resources on random access and scheduling. This is still considered in 3GPP, to my understanding.
sir, how UE is decoding its signal from whole power domain super positioned signal?, kindly reply must...this question is in the context of NOMA session...
The UE is decoding a data signal just as it would do in any other communication system, by running a ML decoding algorithm (e.g., the Viterbi algorithm for block codes), while treating all other signals as being part of the noise. The special aspect is that some users run a decoding algorithm for other user’s data signals and then subtract this data from their received signals before decoding their own data.
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its great to see two pioneers of modern wireless communication☺️
Okay
Excellent talk..Thank you for putting this together
Thanks for the great video! I was wondering whether NOMA requires synchronization between users? For example, do all users need to transmit at the same time for SIC to work? What if their transmissions are half overlapped?
Why didn't the CDMA prevail in future generation as main multiple access technique ?
How can Noma decoding be used at the UE if the strong user doesn't know the channel of the weak user signal ?
Wouldn't successive interference cancellation jeopardize the privacy if the weak user ?
Why Noma can't add advantage for massive mimo case ?
At @14:52 you were talking about considering a line of sight channel as Siso channel but you mentioned that this is unlikely in 5g but I believe with the use of mmwave this is highly likely wouldn't you agree ?
Any recommended reference for code domain Noma and how does it work ?
CDMA isn’t providing any extra radio resource dimensions, it just divides them in a different way between the users. OFDM turned out be easier to implement and give more flexibility.
In downlink NOMA, a user doesn’t need to know the channel of anyone else since all signals reach the user over the same channel. However, the user must know the modulation and coding scheme of the co-users.
Privacy is maintained through cryptography. Wireless is a broadcast medium so anyone can listen and decode signals.
Non-linear processing such as NOMA can bring benefits when there are strong interfering signals, but massive MIMO utilizes user-specific beamforming to make sure that there is little interference between the users.
It is only a situations where massive MIMO cannot suppress interference well that other methods become useful. This could be a LOS scenario with very closely located users.
I recommend the paper that is mentioned in the description of the video.
@@WirelessFuture
Thank you for clarifying things up , but in massive mimo we allocate users same time Freq resources and separate them in beam domain
By Noma we can add more users to the system by sharing the same beam , wouldn't this be and advantage of Noma in your opinion if combined with massive mimo ?
@@yasserothman4023 The problem is that you need to find users with very similar channels so that they prefer the same beam. This is unlikely to happen, except in the LOS case that I mentioned. The rate splitting framework describes in the paper is at least guaranteed to give better performance than massive MIMO in any situation since it is an add on, but my impression is that the gains are marginal.
@@WirelessFuture
I have some questions in rate splitting and I appreciate your feedback , those questions came after reading the paper you mentioned in the video description
1-May I know what does the common message represent in practice , how can we determine its size and content ?
2-How does this scheme (rate splitting) achieve better gains compared to Noma if both depends on successive interference cancellation ?
@@yasserothman4023 1. Section VI in the paper describes that the common message contains a summation of data intended for individual users. It is basically transmitted using TDMA or FDMA, so that each user extracts the part of interest. How to select the right size of the common message depend on the performance metric that you want to maximize. There is a discussion about this at the end of the section, focused on maximizing the multiplexing gain.
2. This is the main topic of the paper, so I cannot repeat it here. The conclusion section provides a summary. “This is due to the fact that the fundamental principle of NOMA consisting in forcing one user in each group to fully decode the messages of other co-scheduled users is an inefficient design in multi-antenna settings.” “Instead, non-orthogonal transmission strategies for multi- antenna settings should be designed such that interference is partially decoded and partially treated as noise based on the rate-splitting (multiple access) literature so as to truly benefit from multi-antenna transmitters (and potentially multi-antenna receivers) and SIC receivers.”
Dear professors, I have questions about NOMA further. what is the control signaling procedure used by NOMA? how do they allocate different frequencies and time slots to send data? I believe the power coefficients are announced by the control signal. I want to know whether NOMA uses ODFM control signaling or a completely different signaling method? Please do answer these questions if possible.
Yes, OFDM is normally supposed to be used and time-frequency blocks can be assigned as in any other system. In addition to normal control signaling, you will also need to inform the involved users of the other users’ coding and modulation schemes and transmit powers, to enable decoding of interfering signals.
@@WirelessFuture thank you professors
Awsome! Dear Professors
Respected sir ,very good video series .
Need assistance on following points:
1.How to understand the mathematics behind Massive MIMO and other topics, like what mathematical equation is used for what problem ,how can we judge it.
2. How to implement it with MATLAB? means from model to simulation ?
what graphs to be drawn specifically ? What to understand from that graph ?
3.A sample to understand the above two points? As trying to apply Optimization algorithm in MIMO and Massive MIMO , but finding difficulty in implementing it successfully.
Shall be highly obliged.
1. We recommend you to read one of our books: "Fundamentals of Massive MIMO" or "Massive MIMO Networks". The latter on is freely available here: massivemimobook.com But apart from the first chapter, it is a more complicated book to read since it uses more realistic models.
2-3. All the simulation code that was used to generate plots in the book Massive MIMO networks are found on its website. This includes solving optimization using CVX+Matlab.
@@WirelessFuture Thank you very much sir
Is NOMA stopped at application of future 5G, why many research talk about NOMA for future 6G?
That is an excellent question, which I think the people who still research NOMA should ask themselves because I don’t know.
When I cover NOMA in Chapter 6 of ”Multiple Antenna Communications and Reconfigurable Surfaces”, I conclude that: 1) It doesn’t increase the sum rate compared to FDMA, but it allows for dividing that rate between the users in different ways. 2) Large sum rate improvements are provided by MIMO, not NOMA - the added benefits of non-linear processing is particularly small in ”Massive MIMO” scenarios with more antennas at the base station than spatial streams/layers.
NOMA can show benefits in papers when compared with some OMA benchmarks (particularly TDMA), but I haven’t seen any examples that are practically convincing. My guess is that many researchers study NOMA because other people recently studied NOMA, in a kind of bad spiral.
One NOMA-like method is grant-free multiple access, which can be useful to handle situations with many users devices that want to transmit small amounts of data. The main benefits come from not having to spend resources on random access and scheduling. This is still considered in 3GPP, to my understanding.
nice discussion...
Please share first paper or nice review paper to start with.
There is a link to a good review paper in the description
sir, how UE is decoding its signal from whole power domain super positioned signal?, kindly reply must...this question is in the context of NOMA session...
The UE is decoding a data signal just as it would do in any other communication system, by running a ML decoding algorithm (e.g., the Viterbi algorithm for block codes), while treating all other signals as being part of the noise. The special aspect is that some users run a decoding algorithm for other user’s data signals and then subtract this data from their received signals before decoding their own data.
@@WirelessFuture thanks for your reply sir...
nice!!!