Field Experiment Results for Rotational OFDM Transmission Implemented on 100 MHz Bandwidth Testbed toward IMT-Advanced System

This paper presents field experiment results for rotational orthogonal frequency division multiplexing (R-OFDM) transmission and demonstrates that R-OFDM is superior to conventional OFDM even in actual radio transmission. R-OFDM is a multi-carrier transmission scheme proposed by the authors. It is characterized by the use of rotational code division multiplexing that enables OFDM to obtain suitable frequency diversity gain. The authors previously implemented R-OFDM on a 100 MHz bandwidth testbed system and evaluated it in the laboratory. Measured results were in good agreement with simulation results. In addition, although the laboratory measurements made it clear that R-OFDM is superior to OFDM, the results assumed the typical radio channel conditions provided by a fading simulator. In order to confirm the effectiveness of R-OFDM, field experiments are indispensable. Therefore, this paper conducts field experiments with a measurement vehicle driven under conditions where OFDM demands frequency diversity. When the coverage of R-OFDM is measured, coverage with a packet error rate (PER) of 1% with OFDM is expanded by 12%. In addition, the measured PER performance against the measured signal-to-noise power ratio (SNR) clarifies that, by using R-OFDM, the SNR required to obtain a PER of 1% can be reduced by 3.3 dB compared with OFDM. Furthermore, OFDM throughput under severe SNR conditions can be improved by R-OFDM and R-OFDM throughput achieves 1.6 times as large as OFDM throughput.