Patent ID: 8098616
Filing Date: 2012-01-17
Classification: H04B

Abstract:
1. A base station apparatus comprising: a deciding section for deciding an allocation for a plurality of mobile stations within a communication area, by judging: 1) whether one of the plurality of mobile stations is a space-division-multiplex (SDM) compatible mobile station by use of a predetermined SDM evaluation criterion; and 2) whether another of the plurality of mobile stations is a space-division-multiple-access (SDMA) compatible mobile station to which a SDMA transmission can be applied along with the SDM compatible mobile station by use of a predetermined SDMA evaluation criterion; wherein the SDM evaluation criterion is calculated based on a channel estimation value and a received channel quality value received from the one of the plurality of mobile stations within the communication area; wherein the SDMA evaluation criterion is calculated based on a received channel quality value received from the another of the plurality of mobile stations and a spatial correlation coefficient which is a measure of correlation between a channel estimation value of an already allocated SDMA mobile station of the plurality of mobile stations and a channel estimation value of the another of the plurality of mobile stations; wherein the another of the plurality of mobile stations is judged to be a SDMA compatible mobile station when the spatial correlation coefficient is below a predetermined spatial correlation coefficient; a partial-space orthogonalizing section for performing a weighting process, for enhancing orthogonality over a propagation path for a SDM transmission, on a first transmission data sequence to be sent by the SDM transmission to the SDM compatible mobile station; a beam forming section for forming a plurality of transmission beams for an output of the partial-space orthogonalizing section in order to send the first transmission data sequence by the SDM transmission to the SDM compatible mobile station and a single transmission beam for a second transmission data sequence to be sent by SDMA transmission to the SDMA compatible mobile station; and a plurality of antennas for simultaneously transmitting the first transmission data sequence using the plurality of transmission beams and the second transmission data sequence using the single transmission beam, wherein, in a case that the SDM compatible mobile station and a SDM uncompatible mobile station are allocated for SDMA communication at a same time, the beam forming section forms a single maximum ratio synthetic directional transmission beam in a single space division multiplex channel to the SDM uncompatible mobile station, and forms a plurality of other directional transmission beams in a plurality of other space division multiplex channels to the SDM compatible mobile station, wherein the directional transmission beams are simultaneously transmitted to the SDM uncompatible and SDM compatible mobile stations at the same frequency.