How does the OFDM system receiver decide the OFDM symbol length? [duplicate]

1. How do you calculate OFDM symbol duration?
2. Which factors are determines the carrier spacing in OFDM systems?
3. How many time samples are in the useful part of an OFDM symbol?
4. How to calculate number of subcarriers in OFDM?

How do you calculate OFDM symbol duration?

The duration of your ofdm symbol is Ts=Tt/(N+Ng).

Which factors are determines the carrier spacing in OFDM systems?

Figure 8.2: Subcarrier spacing is determined by a condition of orthogonality between the subcarriers, which allows to decode each one without interference form its neighbors.

How many time samples are in the useful part of an OFDM symbol?

In 802.11, each OFDM symbol is 4 μs long. At 20 MSPS sampling rate, this means each OFDM symbol contains 80 samples.

How to calculate number of subcarriers in OFDM?

If you divide the channel bandwidth (20 MHz) by the subcarrier bandwidth (312.5 kHz) you will see that 802.11a/g comprises 64 subcarriers.