To reduce a load of DPC processing, while maintaining an effect of removing an influence on communication quality caused by radio wave interference by DPC in a multi-user MIMO system.
When a base station forms transmission beams respectively associated with a plurality of mobile stations, using incoming direction estimation values of spatial multiplex related to the plurality of mobile stations, a multi-user MIMO system performs DPC upon transmission signals to mobile stations, as pre-processing, that may produce radio wave interference between the mobile stations, by limiting the number of mobile stations, which prevent radio wave interference between the mobile stations caused by the transmission beam, to less than the total number of the mobile stations. A DPC switch 20 instructs a DPC encoding unit 13 not to execute the DPC processing, when the influence on communication quality by the radio wave interference between the mobile stations is sufficiently small not to be influenced by the presence or absence of DPC.
MATSUMOTO TOMOKO
KONISHI SATOSHI
Masatake Shiga
Yoshifumi Saeki
Naoki Ofusa