Configurations and performance evaluations for a long-delay multipath interference based on the combinational use of an adaptive array antenna and multipath equalizers

Long-delay multipath interference is defined as a delayed signal located outside the guard interval of OFDM systems. An adaptive array antenna is often used to suppress long-delay multipath interference; however, the performance degrades when the desired and interference signals come from nearly the same direction. In these situations, a multipath equalizer in the time domain is very effective for suppressing the interference signal. In this paper, we propose three configurations based on a combinational use of an adaptive array antenna and a multipath equalizer as a remedy for long-delay multipath interference. We evaluated the performance using a computer simulation. The results show that excellent performance can be achieved even when the directions of desired and interference signals are close as well as when the interference signal comes from arbitrary directions.