DAC implementation in OFDM

In an OFDM transmitter, after IFFT & CP block, a DAC block is used.Since the output of IFFT is complex, and the input to DAC should be an integer, how can we integrate the two blocks? I implemented OFDM (upto CP block) in MATLAB but I could not integrate DAC with it.

Regards Ehsan

• Is there any code available in matlab which can be used to convert 2-level digital signal(1 and -1) into analog? – user26196 Jan 27 '17 at 10:01

2. Pulse shaping - if a physical channel should be modeled (for example a wireless channel), the analog output of the DAC must be simulated. This is implemented by converting every input sample into an impulse that is weighted with the sample's value. In the simulation the impulse itself consists of $L$ samples, of course, that mimic the analog signal. $L$ is the oversampling factor (not to be confused with the OFDM oversampling that is achieved by zero padded subcarriers). The simplest impulse shape is a rectangle, i.e. every sample in the simulation is just repeated $L$ times.