Radio transmission control method, radio receiver apparatus, and radio transmitter apparatus

Abstract

Conventionally, if the number of transmission antennas is greater than that of reception antennas, different signals simultaneously transmitted from the transmission antennas cannot be separated from one another at the receiving end, resulting in a significant degradation of received-signal quality. A transmitter and a receiver each have a plurality of antennas. The transmitter transmits a pilot signal. The receiver receives the pilot signal, calculates transmission-related information corresponding to the pilot signal, selects, based on this calculated information, a transmission signal to be used by the transmitter, and notifies the transmitter of the selected signal. The transmitter selects, from the informed transmission signal, transmission antennas and uses the selected antennas to transmit information signals, so that a signal separation can be easily performed at the receiving end.

1 . A radio communication method for a radio communication system in which output signals are generated from a plurality of information signals and then transmitted to a system of communication partner from a plurality of antennas, comprising:
 notifying the system of communication partner of a first weight for one of the plurality of information signals with respect to the plurality of antennas, and a second weight for another one of the plurality of information signals with respect to the plurality of antennas;   generating a first operation result by multiplying the one of the plurality of information signals by the first weight, and generating a second operation result by multiplying the another one of the plurality of information signals by the second weight; and   generating based on the first operation result and the second operation result, a plurality of the output signals each corresponding to one of the plurality of antennas, and transmitting the plurality of the output signals to the system of communication partner.   
   
   
       2 . The radio communication method according to  claim 1 , wherein the transmission comprises generating the plurality of the output signals by one of applying different modulation schemes and applying different encoding methods between the first operation result and the second operation result. 
   
   
       3 . A radio communication system in which output signals are generated from a plurality of information signals and then transmitted to a system of communication partner from a plurality of antennas, comprising:
 a weight notifying device for notifying the system of communication partner of a first weight for one of the plurality of information signals with respect to the plurality of antennas, and a second weight for another one of the plurality of information signals with respect to the plurality of antennas;   an operation device for generating a first operation result by multiplying the one of the plurality of information signals by the first weight, and generating a second operation result by multiplying the another one of the plurality of information signals by the second weight; and   a transmission device for generating, based on the first operation result and the second operation result, a plurality of the output signals each corresponding to one of the plurality of antennas, and transmitting the plurality of the output signals to the system of communication partner.   
   
   
       4 . The radio communication system according to  claim 3 , wherein the transmission device generates the plurality of the output signals by one of applying different modulation schemes between the first operation result and the second operation result and applying different encoding methods between the first operation result and the second operation result.