Performance Comparisons of Power Loaded OFDM Systems Over Peak Power Limited Channels
Orthogonal Frequency Division Multiplexing (OFDM) has been widely adopted in many applications and standards for a number of benefits including high efficiency and immunity against the frequency-selective channel. Power loading, which is a technique that allocates different amount of power for each subcarrier, further enhances the system performance by maximizing mutual information, reducing Bit Error Rate (BER) or improving other aspects of the communication system. OFDM, however, suffers from high Peak-to-Average Power Ratio (PAR) due to its wide dynamic range of time-domain waveforms. This makes OFDM symbols be affected by non-linearity resides at the Power Amplifier (PA), causing the power efficiency to decrease and symbols to be distorted.