Transmit diversity for frequency selective channels in UMTS-TDD
U. Ringel, Ralf Irmer, Gerhard Paul Fettweis · 2003
Multipath propagation and fading are typical characteristics of wireless communication channels. Simultaneously, they are also the most limiting factors for high speed data rates. The paper investigates the performance of systems using multiple transmit antennas (MISO - multiple input single output) in frequency-selective channels, which combat fading and exploit multipath propagation. The system considered is UMTS-TDD. The investigations focus on different antenna configurations and on correlated propagation channels. The impact of Doppler-spread due to the velocity of the mobile user is considered. The problem of asymmetrical data-rates on uplink and downlink is addressed.