Adaptation of modulation and coding for OFDM packet transmission

A novel protocol is proposed for adaptive modulation and coding for orthogonal frequency division multiplexing (OFDM) in packet radio networks. Previous protocols in the literature rely on channel measurements or parameter estimates to provide channel state information, which is then processed to determine the appropriate transmission parameters. Our proposed protocols avoid the complexity of making measurements or estimates; instead, we use simple statistics that are derived easily from the receiver´s demodulator and decoder. Employing only these simple statistics from the reception of the most recent packet, our protocol first determines the code rate for the next packet and then selects the modulation format to be used on each subcarrier. The throughput results for our adaptive OFDM transmission protocol are obtained analytically and by simulation.