*2.6.3 OFDM receiver*

At the OFDM receiver's side, the reverse process of transmitter side is performed. The block diagram representing the OFDM receiver is shown in **Figure 14**. The transmitter-generated signal is further transmitted over the channel for receiving. The receiver receives the baseband OFDM signals, and then it passes through a low-pass filter to remove the unwanted signals. The baseband signals are then sampled and digitized using ADCs, and a forward FFT is used to convert back to the frequency domain.

**Figure 12.** *OFDM transmitter.*

### **Figure 13.**

*OFDM transmitter simple block diagram.*

### **Figure 14.**

*OFDM simple block diagram of OFDM receiver.*

By means of an appropriate symbol detector, the frequency domain signals are converted to N parallel streams, and each stream is converted to a binary stream. A sequential stream combining all binary stream acts as an estimate of the original binary stream at the transmitter side.

### *2.6.4 Significance of the OFDM system*


OFDM system has also certain limitations rather than the abovementioned potential capabilities. High peak-to-average power ratios (PAPR) of transmitted signal are the major drawback of the OFDM signal. OFDM is very sensitive to carrier frequency offset and hence becomes difficult to synchronize during sharing of subcarriers different transmitters.
