| MIMO Hello all,
Firstly, thank you to anybody kind enough to help me in a reply. I'm a university physics student on placement and I need to learn as much as I can about MIMO (and wifi in general). If anybody could point me in the right direction of some good literature on the subject (my google searches haven't produced anything too useful) I'd be very grateful.
I also need to find out the kind of transmission and recieve powers that are involved with MIMO wifi?
Thank you!
Tom |
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 tschmidtPremium,MVM
join:2000-11-12
Milford, NH
kudos:5 | May want to start with the specs, they are available free on the IEEE site to anyone 6-mo after ratification.
»standards.ieee.org/about/get/802/802.11.html
/tom |
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 mozerdLight Will Pierce The DarknessPremium,MVM
join:2004-04-23
Nepean, ON | reply to Tom Tom Tom
said by Tom Tom Tom :I'm a university physics student on placement and I need to learn as much as I can about MIMO (and wifi in general). If anybody could point me in the right direction of some good literature on the subject (my google searches haven't produced anything too useful) I'd be very grateful.
I also need to find out the kind of transmission and recieve powers that are involved with MIMO wifi?
802.11 with Multiple Antennas for Dummies
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David Mozer
IT-Expert on Call
Information Technology for Home and Business |
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 AnavSarcastic Llama? Naw, Just AcerbicPremium
join:2001-07-16
Dartmouth, NS
kudos:3 | Hey Mozerd, did you write that article or was it written for you? ;-P |
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| reply to Tom Tom Tom
tschmidt, thank you for the spec link!
mozerd, that paper looks ideal, gonna check it out now, thanks a bunch.
Tom |
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| reply to mozerd
Hi again mozerd (or anyone else willing to help!), that paper was a good read, can you tell me if I've got the right idea when it comes to spatial multiplexing...
For each sub carrier (which is a certain band of frequencies), an independent signal is sent out from each antenna (i.e. TX antenna 1 is sending signal x1, which is different in its content to signal x2 coming out of TX antenna 2).
Then, each RX antenna picks up all the different signals (modified by an attenuation and phase factor).
So does this mean that each 802.11 TX antenna using OFDM (with 64 subcarriers) can send out 64 independent signals, meaning that any given RX antenna picks up N*64 independent signals, where N is the number of transmit antenna's?
How does it go about separating all the signals? I guess it separates them by wavelength first to separate the sub carriers. Is this done by a series of band-pass filters? Then you have a bunch of signals for each sub carrier. I understood for direct-mapped, how, mathematically you can apply the inverse of the gain matrix to the received signal to recover a vector which contains approximations to the original signals (with noise giving the error). But how is this actually done physically?
Then... once you've recovered and separated all the individual signals on each RX antenna, what's the procedure for adding them all up across the RX antenna's.
i.e. RX1 has received y11 + y21 + y31 + y41 + y51
RX2 has received y12 + y22 + y32 + y42 + y52
how do you go about getting y11 and y12 together (or y51 and y52)
Sorry for the overload of questions, hope I've at least loosely grasped what's going on here, thanks for any help!
Tom |
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mozerdLight Will Pierce The DarknessPremium,MVM
join:2004-04-23
Nepean, ON | There are a number of proprietary methods used in exploiting Spatial multiplexing -- Airgo Networks now owned by Qualcomm did a lot of work in this area but unfortunately most of their paper is now hidden from public view.
following is a good explanation of the subject -- however the Airgo method is far superior in how spatial-multiplexing and multipath is exploited.
How does spatial multiplexing work
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David Mozer
IT-Expert on Call
Information Technology for Home and Business |
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| reply to Tom Tom Tom
Hi,
»en.wikipedia.org/wiki/Fast_Fourier_transform
To separate the subcarriers, you do Fast Fourier Transform...
Dreamer |
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