Coded frequency-domain link adaptation scheme for OFDM in TDD mode

The link adaptation scheme in current orthogonal frequency division multiplexing (OFDM) systems such as IEEE802.11a only considers the channel variation in the time-domain, and assumes all the data subcarriers use the same modulation mode and transmit power once the data rate is determined. However, in a frequency-selective fading environments, the error probability performance of OFDM is severely degraded by the subcarriers where deep fading occurs. In order to deal with this issue, we propose a coded frequency-domain link adaptation scheme for OFDM in the time division duplex (TDD) mode. This scheme is based on a concatenation of the channel coding and the adaptive bit and power loading. The simulation results show the proposed scheme can significantly improve the bit error rate (BER) performance compared with other schemes.