An OFDM system employs 260 data subcarriers, 40 pilot subcarriers, and 34 guard subcarriers to transmit data through a wireless channel. QPSK modulation is employed for each subcarrier.
a)Determine the system bandwidth if the subcarrier frequency spacing is 15 KHz.
b)To combat multipath, a cyclic prefix of 1/4 of the OFDM symbol is employed. Find the total transmission time of an OFDM symbol and calculate the data rate of the system.
c)If the delay spread of the wireless channel is 20 s, find the maximum data rate that can be supported by the system.
Employing a cyclic prefix of 4.7 s, is it possible to maintain the data rate achieved in b) while keeping the same number of pilot and guard subcarriers, the same system bandwidth, but with BPSK modulation on each subcarrier? Show your calculations.