Contents
Why orthogonality is important in OFDM?
In OFDM, multiple closely spaced orthogonal subcarrier signals with overlapping spectra are transmitted to carry data in parallel. This maintains total data rates similar to conventional single-carrier modulation schemes in the same bandwidth.
How many symbols are there in OFDM?
An 802.11a OFDM carrier signal (burst type) is the sum of one or more OFDM symbols each comprised of 52 orthogonal subcarriers, with baseband data on each subcarrier being independently modulated using quadrature amplitude modulation (available formats: BPSK, QPSK, 16-QAM, or 64-QAM).
Do you need to oversample in OFDM?
There is no need to apply oversampling in OFDM, nor is oversampling required to recover input signals. However, in practical implementations you have to consider some additional constraints regarding the signal’s bandwidth. The WARP v2 radio board is clocked with 40 MHz, i.e., the Nyquist frequency is 20 MHz.
What is the sampling rate of an OFDM signal?
When all subcarriers are modulated the (baseband) bandwidth of an OFDM signal is approximately f s / 2, where f s is the sampling rate. An ideal rectangular filter before A/D conversion would be needed at the receiver to avoid anti-aliasing.
When do you add samples to an OFDM symbol?
2 Answers. An OFDM symbol is the time-domain representation of the symbols concurrently transmitted over all subcarriers. It consists of just as many samples as there are OFDM subcarriers since it is calculated as the IDFT of all subcarriers’ symbols. When adding the cyclic prefix, you add samples.
The duration in seconds is the number of samples times the time per sample. When oversampling, the symbol duration extends according to the oversampling factor. Thanks for contributing an answer to Signal Processing Stack Exchange!