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Just as the title says. I have searched for a whole day and haven't found any confidential materials to verify whether there is a pulse shaping after OFDM modulation in NB-IoT?

For example, in https://www.nxp.com/docs/en/white-paper/3GPPEVOLUTIONWP.pdf in page 15, it mentioned that there is a procedure named, Cyclic prefix and pulse shaping. And the purpose is desripted as "pulse shaping is employed to prevent spectral regrowth.", However, which kind of pulse shaping is unclear.

Besides, I have browsed the referred materials listed in the end of the paper, for most likely references:

  1. 3GPP TS 36.201 – v1.0.0, LTE Physical Layer – General Description, http://www.3gpp.org/ftp/Specs/archive/36%5Fseries/36.201/
  2. 3GPP TS 36.211 – v1.0.0, Physical Channels and Modulation, http://www.3gpp.org/ftp/Specs/archive/36%5Fseries/36.211/
  3. 3GPP TS 36.212 – Multiplexing and Channel Coding, http://www.3gpp.org/ftp/Specs/archive/36%5Fseries/36.212/
  4. 3GPP TS 36.213 – v1.0.0, Physical Layer Procedures, http://www.3gpp.org/ftp/Specs/archive/36%5Fseries/36.213/

However, there is still no description about the kind of pulse shaping after OFDM modulation. In other words, if I want to send out the NB-IoT signal (which is much similar with LTE) after OFDM modulated, how can I implement it before DAC? Any help would be appreciated!

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Usually windowing is used after FFT.

Ref: https://cn.mathworks.com/help/lte/ref/lteofdmmodulate.html

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  • \$\begingroup\$ Thank you for your answer. However, I am still not sure whether the windowing is a kind of pulse shaping. More specifically, is there a formal equation for every transmitted signals? For example, if we use the sine wave as the pulse shape, then the sended out signal can be expressed as a sine function. \$\endgroup\$ – desword Sep 14 '17 at 14:17
  • \$\begingroup\$ It's not normal pulse shapping as we see in single carrier. For OFDM, we only need to care about the phase disconectivity between two OFDM symbols. Windowing is used to smoothing disconectivity by introducing an overlap area: 'ramp down' to end of last symbol and 'ramp up' to start of next symbol. CP should be extended by length of overlap area. \$\endgroup\$ – Qiang Gu Sep 14 '17 at 15:26

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