Experimental evaluation of SDM-COFDM using hierarchical ICI canceller with pilot-based channel tracking in fast multipath fading

We develop an SDM (space division multiplexed)-COFDM (coded orthogonal frequency division multiplexing) prototype using a hierarchical ICI canceller with a pilot-based channel tracking scheme. We evaluate the experimental performance of the prototype when the subcarrier modulation scheme is 16QAM, the coding rate is 3/4 and the maximum Doppler frequency is 50 Hz in the 5 GHz band. PER performance with the channel tracking scheme is dramatically improved compared to those without the channel tracking scheme. PER degradation compared with the case when the pilot symbol interval is 3, which is the best case, at PER of 0.1 was less than 2 dB when the pilot symbol interval was less than 93. We calculate the throughput considering the overhead caused by the preamble and pilot signals for channel tracking and found that the pilot symbol interval that provides the optimum throughput ranges from 48 to 60, which depends on CNR.