Transmit Antenna Diversity in Ricean Fading MIMO
Channels with Co-Channel Interference.
Nordic Radio Symposium 2001 (NRS 01) ,
Nynäshamn, Sweden, April 3-5 2001.
Transmit antenna diversity using closed loop and open loop modes are
compared in environments with line of sight propagation and spatially
and temporally non-white noise. The connection between the
feedback channel capacity in
closed loop modes and the channel coherence time is investigated. It
is shown that in LOS environments, the requirements on the feedback
channel bit rate is lower. Furthermore, we derived the beamforming
vector in closed loop transmit diversity with directional interference
and showed how this gives an
equivalent gain in SNR of about 3 dB at the receiver, even at a
beamforming weight phase resolution of 90 degrees.