i read some where that FBMC(filter bank multi carrier ) is not easily applicability to MIMO, is it true?, if it is true, then how massive MIMO uses FBMC??
You might want to read this paper:
http://upcommons.upc.edu/e-prints/bitstream/2117/8109/1/published_FutureNetworkSummit2010.pdf
The short version is that OFDM incorporates a cyclic prefix in the guard interval, whereas FBMC has no guard interval. This makes FBMC more spectrally efficient, like a single-carrier scheme, but also more vulnerable to multipath distortion.
As a result, if channel state information assumed by transmitters and receivers in MIMO is less than perfect, OFDM will have the advantage. FBMC will experience interference, such as intersymbol interference, that OFDM may well not experience (depending how bad your channel estimation is).
FBMC uses decision feedback equalizers. So you have to hope these are up to the task.
The complexity is more compared to simple OFDM which can be implemented with FFT. In FBMC we need filter banks. The more the subcarriers the more the filter banks. Also for massive mimo we need a lot more. But many techniques exist in literature in which structure of filter banks can be reduced and hence complexity .
There are several FBMC methods, which act differently in MIMO systems. For example FBMC/OQAM aka SMT (Staggered Multi-Tone) is shown to have problems with common spatial diversity techniques such as Alamouti scheme. For more detail on this topic, see http://www.ict-phydyas.org/teamspace/internal-folder/FBMC-Primer_06-2010.pdf
On the other hand, another FBMC method called CMT (Cosine Multi-Tone) which is based on VSB/PAM, is well-suited to massive MIMO communications. see http://arxiv.org/pdf/1402.5881.pdf
The problem with the scheme FBMC/OQAM is the presence of the interference terms. so it can't be applied symbol-wise; However, it can be applied block wise. One my exploit also what is called modified Alamouti.( conjugate time reversed version of the second block)
Unlike OFDM which require single-tap for equalisation, FBMC-OQAM needs multi-tap one due to the prototype filter. This is major drawback of FBMC-OQAM hindering it to be chosen as the radio carrier for 5G and beyond 5G systems.
Regards,
Dr. KC
you can read this article:
"5G: An Idea Whose Time Has Come", International Journal of Scientific and Engineering Research 8(3),March 2017
it's because FBMC send real data so the orthogonality condition is valid if we take the real part of it this lead to what is called"intrinsic interference"that is the main source of (MIMO&Channel Estimation)problems.
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