What's the function of sampling factor in wireless standards?

[safwatonline]

Hi,
i was wondering what is the significant of the sampling factor in wireless standards?
i.e. why n=8/7 and how it is related to fs? and why are we using it along with the "8000" factor in the fs calculation.
seems really weired to me.
thnx.

 

[safwatonline]

what is sampling factor

i think the factor n resembles some oversampling factor to ease the filter design.
however, i don't know the 8000 factor?
beside i noted that fs=n*BW doesn't satisfy nyquist, i think this is related to complex signal , anyone can explain this to me?

 

[changfa]

wimax sampling factor

The sampling factor 8/7 in Wimax is used to increase data rate. The story is that in Wimax there is guard tone at each end of IFFT (the number of guard tone has some historic reasons. Anyway, it is kind of fixed.). It is found out that in doing so we are too conservative in using IFFT tones. So, Wimax proposes sampling factor >1 to increase data rate.

The only place you can find this explanation is in the book written by 802.16 committee. It is called "IEEE 802.16, inside..." try Amazon

 

[sparso]

fi/fs=m/n

The relationship is Fi/Fs = M/N where,

Fi = Freq. of interest
Fs = The Sampling Freq.
M = # of cycles
N = # of samples.

Fi/Fs = does not have to be an integer but M and N both have to be integers for coherent sampling i.e.
to prevent spectral leakage.

 

[safwatonline]

sampling factor wimax

The relationship is Fi/Fs = M/N where,

Fi = Freq. of interest
Fs = The Sampling Freq.
M = # of cycles
N = # of samples.

Fi/Fs = does not have to be an integer but M and N both have to be integers for coherent sampling i.e.
to prevent spectral leakage.

thnx for ur answer, however, the question is why this equation doesn't obey Nyquist
fs=8/7(fin)