Patent ID: 8971962
Filing Date: 2015-03-03
Classification: H04B

Abstract:
1. A distributed antenna system comprising a base station device having a plurality of antenna ports, a terminal having a plurality of antennas, and an antenna switch configured to switch a connection between antennas of a plurality of distribution devices that are spatially distributed and the antenna ports of the base station device, in uplink and downlink communications, wherein the terminal is configured to conduct SISO, SIMO, and/or MIMO communication by using one or more of the plurality of antennas for transmission or reception as determined by the base station device: and the base station device comprises a control unit the control unit comprising: a traffic information collection unit configured to collect traffic information on the uplink and downlink communications and store the traffic information in a traffic information database in the control unit: a channel state information collection unit configured to collect information on radio propagation channels from the distributed antennas to the antennas of the terminal and store the information on radio propagation channels in a channel state information database in the control unit: and a changeover determination unit configured to determine a changeover between a first communication using a plurality of antennas for communication with one terminal and a second communication using one antenna for transmission or reception with respect to one terminal, on a basis of information stored in the traffic information database and the channel state information database, and when a traffic volume of the terminal is lower than a given first threshold value, the changeover determination unit is configured to determine to conduct the second communication, when the traffic volume of the terminal is the first threshold value or higher, the changeover determination unit is configured to conduct a first determination that the terminal applies the first communication when the terminal is applying the first communication and a communication speed or throughput by the combination of the present antennas is a given second threshold value or higher, when the terminal is applying the first communication, and the communication speed or throughput by the combination of the present antennas is lower than the second threshold value, or the terminal is not applying the first communication, (i) the changeover determination unit is configured to determine to conduct a second determination that, when the plurality of antennas is combined together, the terminal applies the first communication if the communication speed or throughput is a given third threshold value or higher, and the terminal applies the second communication if the communication speed or throughput is lower than the third threshold value, or (ii) the changeover determination unit is configured to determine to conducts a third determination that the terminal applies the first communication if the number of other teuninals using the antenna used by the subject terminal is a fourth threshold value or higher, and applies the second communication if the number of other terminals is lower than the fourth threshold value.