OFDM with guard interval versus OFDM/offsetQAM for high data rate UMTS downlink transmission

OFDM modulation using a guard interval, denoted OFDM/QAM, in this paper, is well known for its robustness to multipath time varying propagation channels, and therefore used in several broadcasting and high data rate radio LAN standards. OFDM/OQAM modulation is an alternative to it, which has the advantage not to require the use of a guard interval, which leads to a gain in spectral efficiency. In this paper, we recall the main characteristics of OFDM/OQAM, and compare it to the OFDM/QAM in a realistic 3G context. We propose optimized modulation parameters and provide simulation results. The study confirms the interest of considering OFDM modulation for high data rate UMTS downlink transmission. Besides, in that context, the gain in spectral efficiency allows OFDM/OQAM to outperform OFDM/QAM performances.