Re: [Discuss-gnuradio] OFDM Mod Block - how is it working?
On Tue, 09 Jul 2019 at 17:42:11 +0200, lilijobo1 lilijobo1 wrote: > The thing is that I dont really get how the parameters > occupied tones and the FFT length work in that case. > Is the occupied tones equal to the numer of subcarriers? If yes where do get > to know the subcarrier spacing because if Im right this is different for > LTE or 802.11a . > > And what about the parameter FFT length? Occupied tones determines the number of used (occupied) carriers, i.e. the number of carriers which contain data and pilots. The number of carriers which can be used at most is determined by the FFT length. Carrier spacing Δf_c is determined by Δf_c = 1/T_s where T_s is the length of the OFDM symbol (cyclic prefix not included). Assuming a sampling rate of f_s you get Δf_c = 1/(N·(1/f_s)) = f_s/N where N is the required length of the FFT. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] OFDM Mod Block - how is it working?
Hi, I'm working with grc and a LimeSDR board and saw that there is the "OFDM Mod" Block available that I thought I could use to generate a broadband signal that is similar to a channel in LTE. In detail I want to generate a signal with a known bandwidth like 5MHz and analyze how the LimeSDR works with that for different frequencies and gains. Therefore I just took a random source the OFDM Mod block and the Limesuite sink ( Gr-limesdr Plugin from Myriad) to generate such a signal. The thing is that I don't really get how the parameters "occupied tones" and the "FFT length" work in that case. Is the occupied tones equal to the numer of subcarriers? If yes where do get to know the subcarrier spacing because if I'm right this is different for LTE or 802.11a . And what about the parameter "FFT length"? I would appreciate any help or suggestions. Thank you in advance Greetings Johannes ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
