Patent ID: 8270333

Claim:
A data relaying apparatus for relaying data bidirectionally transmitted between a first communication apparatus and a second communication apparatus, the data relaying apparatus comprising: a first symbol string generator configured to generate, in accordance with a first modulation method, a first symbol string from first data transmitted from the second communication apparatus; a second symbol string generator configured to generate, in accordance with a second modulation method, a second symbol string from second data transmitted from the first communication apparatus; a combining unit configured to combine a first symbol and a second symbol from the first symbol string and the second symbol string, respectively, by calculating an exclusive OR on the first symbol and the second symbol to generate a third symbol string to be multicasted to the first communication apparatus and the second communication apparatus; and a modulation and coding method determining unit configured to determine the first modulation method and a first coding method and the second modulation method and a second coding method so that a sum of spectrum efficiencies of a first link to the first communication apparatus and a second link to the second communication apparatus becomes maximum, wherein the first modulation and the second modulation are controlled to be same by adjusting code rates of the first and second symbol strings.