I am over some exercises from your new book. In exercise 8.15 b) the combining vector w is searched which maximizes the SNR at the receiver. As solution w=h/IIhII is given. That is the vector of max. transmission comb., but we are in the receiving case (w=h^H). What did I leave out? Thanks for your work, perhaps you find a free minute to answer.
hello prof ! Great talk... just curious to know whether the terms which are frequently used in wireless communication, that is : ergodic rate and ergodic capacity can be used interchangeably or do they mean different ?
Some people use these words interchangeably, but they could also have specific meanings: Capacity is the theoretically maximum data rate that can be achieved over a channel, while the rate is just one bit rate that is achievable. One can choose to use a rate smaller than capacity because it leads to a more practical implementation.
Thanks for the interesting talk. Maybe I missed it, but when the signal travels along the line, we get a different phase at every single radiating element. Are there any phase shifters at the single elements or does the distance between the elements determines the fix phase shift.?
The fiber operates in an “antenna selection” manner, so only one of the elements transmits the signal - chosen depending on where the user is. Hence, there is no need to phase-shift the signals.
We transmit light over the fiber and must convert it into electro magnetic signal to transmit it over the air - do we have opto-electronic converters at every single antenna element? Thank you.
It is the actual THz RF signal that is sent over the plastic microwave fiber, so no further conversion is needed. The material choices are discussed at some point in the video.
Many thanks for all of your valuable work. I am over your book right now. Just a short question, please. Once you name the term R=E{y[l]*y[l]^H} correlation matrix and later I read the term C=E{n*n^T} as covariance matrix of n. These are similar expressions - so, when is it the correlation matrix and when the covariance matrix? Thank you.
@@WirelessFuture Thank you, so the term E{y*y^H} can have values outside the interval of -1 to +1, in general the correlation matrix has values within that interval - many sources say so. They contain the corr.coefficients. That was confusing to me. I think one must kind of normalize the above term to get into the interval.
@@nelebauer7864 You are right that correlation can be defined in multiple ways. The “Pearson correlation coefficient“ is a normalized covariance measure that gives a value between +1 and -1. This is indeed what many people associate correlation with. What we defined in the book is also known as the auto-correlation matrix: en.m.wikipedia.org/wiki/Autocorrelation
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I am over some exercises from your new book. In exercise 8.15 b) the combining vector w is searched which maximizes the SNR at the receiver. As solution w=h/IIhII is given. That is the vector of max. transmission comb., but we are in the receiving case (w=h^H). What did I leave out?
Thanks for your work, perhaps you find a free minute to answer.
hello prof ! Great talk... just curious to know whether the terms which are frequently used in wireless communication, that is : ergodic rate and ergodic capacity can be used interchangeably or do they mean different ?
Some people use these words interchangeably, but they could also have specific meanings: Capacity is the theoretically maximum data rate that can be achieved over a channel, while the rate is just one bit rate that is achievable. One can choose to use a rate smaller than capacity because it leads to a more practical implementation.
Thank you sir for your kind suggestions @@WirelessFuture
Thanks for the interesting talk. Maybe I missed it, but when the signal travels along the line, we get a different phase at every single radiating element. Are there any phase shifters at the single elements or does the distance between the elements determines the fix phase shift.?
The fiber operates in an “antenna selection” manner, so only one of the elements transmits the signal - chosen depending on where the user is. Hence, there is no need to phase-shift the signals.
We transmit light over the fiber and must convert it into electro magnetic signal to transmit it over the air - do we have opto-electronic converters at every single antenna element?
Thank you.
It is the actual THz RF signal that is sent over the plastic microwave fiber, so no further conversion is needed. The material choices are discussed at some point in the video.
Many thanks for all of your valuable work. I am over your book right now. Just a short question, please. Once you name the term R=E{y[l]*y[l]^H} correlation matrix and later I read the term C=E{n*n^T} as covariance matrix of n. These are similar expressions - so, when is it the correlation matrix and when the covariance matrix?
Thank you.
Covariance and correlation matrices are defined on Page 74. They are the same thing when the variable has zero mean.
@@WirelessFuture Thank you, so the term E{y*y^H} can have values outside the interval of -1 to +1, in general the correlation matrix has values within that interval - many sources say so. They contain the corr.coefficients. That was confusing to me. I think one must kind of normalize the above term to get into the interval.
@@nelebauer7864 You are right that correlation can be defined in multiple ways. The “Pearson correlation coefficient“ is a normalized covariance measure that gives a value between +1 and -1. This is indeed what many people associate correlation with.
What we defined in the book is also known as the auto-correlation matrix: en.m.wikipedia.org/wiki/Autocorrelation
Great episode!
Can you guys make a video on limiting the radiation pls
👍👍👍👍