Radio transmission apparatus and radio transmission method
View Patent ↗Data streams stored in buffers are modulated by modulation sections. Multipliers multiply the signals output from the modulation sections by weights output from a weight control section. The signals output from the multipliers are added up by addition sections, subjected to radio transmission processing by transmission radio sections and sent through antennas. A buffer control section controls the buffers based on a retransmission count output from a retransmission count detection section. The weight control section outputs weights different from weights at the time of previous transmission to the multipliers every time data is retransmitted. This allows a diversity gain at the time of data retransmission to be increased even if a time variation of the propagation path environment for radio signals is slow.
1. A transmission apparatus comprising:
a multiplier that multiplies a plurality of streams by a plurality of weights; and
a transmitter that transmits the plurality of streams multiplied with the weights using a plurality of antennas,
wherein correspondence relationships between the streams and the weights are derived from feedback information which is transmitted from a reception apparatus for a previous transmission.
2. The transmission apparatus according to claim 1 , wherein the multiplier derives the correspondence relationships such that, in an even-numbered transmission, weights used in an odd-numbered transmission are used as weights for different streams in the even-numbered transmission from streams used in the odd-numbered transmission.
3. The transmission apparatus according to claim 1 , wherein, in an even-numbered transmission, the transmitter retransmits the same data as data of an odd-numbered transmission.
4. A transmission method performed by a transmission apparatus comprising:
multiplying a plurality of streams by a plurality of weights; and
transmitting the plurality of streams multiplied with the weights using a plurality of antennas,
wherein correspondence relationships between the streams and the weights are derived from feedback information which is transmitted from a reception apparatus for a previous transmission.
5. The transmission apparatus according to claim 1 , wherein a first weight multiplied on a first stream in an even-numbered transmission is the same as a second weight multiplied on a second stream in an odd-numbered transmission.
6. The transmission apparatus according to claim 1 , wherein the plurality of weights used in an even-numbered transmission are selected from among the plurality of weights used in an odd-numbered transmission.
7. The transmission apparatus according to claim 1 , wherein the feedback information includes propagation path information transmitted from the reception apparatus.