Dear Eduard,

welcome,

The FIR and the IIR filters are modeled in time domain by their impulse response h[n] and in the discrete time domain by their transfer function H(z) in the z domain. Both descriptions can be transformed to each other.

If H(z) is known one can convert it to h[n]. Whenever one wants to add filters in a linear system, one uses either models according to the analysis required.

Best wishes

Dear sir

The filtered you mentioned added in the time domain in OFDM systems. Unduly used low pass filer with window mask to achieve paaband filtering i.e F-OFDM waveforms candidate. In the time domain the impulse response of the filter is multiplied by the OFDM signal as a linear convolution. The operation leads to increase the the size of the F-OFDM stumble and thus the PAPR value increase.

Dear Eduard, how are you ?

There are some ways to model digital filters in the time domain or frequency domain. Considering your implementation, you can choose Difference Equation which can be obtained from H(z), its Z transform or in the case of FIR Filter, from the impulse response h[n].

However, it is important to know the specification of 5G bandpass filter. Then, use some design methodology to obtain the filter in one of these formats.

Best regards,

Fabrício Simões