Multimedia mobile communication systems are expected to be realized in the
near future. In such systems, multipath fading can cause severe degradation
s of the quality of the communications due to its wide bandwidth, especiall
y in urban areas. Adaptive array antennas can be attractive solution for ov
ercoming the multipath fading. Suppression can be achieved with the adaptiv
e array by cophasing and combining multipath signals in the space and time
domain. On the other hand, the concept of software antenna has been propose
d. The software antenna recognizes radiowave environments and appropriately
reconfigures itself for the signal processing required by the recognized e
nvironment. Efficient implementations can be expected if these functions ar
e realized by the software. In this paper, we propose two types of the adap
tive array systems which is reconfigurable depending on the radiowave envir
onment as a realization of the concept of the software antenna. They recogn
ize the environment by using the eigenvalue decomposition of space domain c
orrelation matrices and reconfigure their structures of the signal processi
ng. The principle and performance are examined by theoretical means and thr
ough computer simulations.