Howtosignalprocessing
- Why this cyclic prefix is important in OFDM?
- What is the role of the cyclic prefix?
- What will happen if we append zeros instead of a cyclic prefix?
- What is the relationship between the number of guard band carriers and the cyclic prefix length?
Why this cyclic prefix is important in OFDM?
Cyclic prefix is inserted to avoid intersymbol interference due to the multipath channel. In practice, CP-OFDM modulator is implemented via the computationally efficient fast Fourier transform (FFT).
What is the role of the cyclic prefix?
Use of cyclic prefix is a key element of enabling the OFDM signal to operate reliably. The cyclic prefix acts as a buffer region or guard interval to protect the OFDM signals from intersymbol interference.
What will happen if we append zeros instead of a cyclic prefix?
The main idea of using Cyclic prefix in OFDM systems is because of 2 reasons, 1) To eliminate ISI from previous symbol. If an OFDM symbol is Zero padded instead of cyclic prefix, ISI due to adjacent symbol still gets eliminated, but it cannot be modeled using circular convolution.
What is the relationship between the number of guard band carriers and the cyclic prefix length?
The guard band has nothing to do with the cyclic prefix. This is purelly allocation of null subcarriers at the edge of the OFDM symbol which provide buffers between consecutive OFDM symbols to protect the integrity of transmitted signals by reducing intersymbol interference.
