Abstract: Provided is a transmitter for transmitting an orthogonal frequency division multiplexing (OFDM) signal using multiple antennas, including: a subgroup generator to divide data symbols of a frequency domain into a plurality of subgroups; an inverse fast Fourier transform (IFFT) unit to perform an IFFT with respect to each of the subgroups so as to generate partial signals of a time domain corresponding to the plurality of subgroups, respectively; a candidate OFDM signal generator to generate at least two candidate OFDM signals using a combination of the partial signals so that each of the partial signals is transmitted to one of transmit antennas; and a selector to select one of the at least two candidate OFDM signals.

Abstract: A method and apparatus for adaptively transmitting the same data, i.e., multicast/broadcast data, according to channel quality to a receiving group including one or more terminals that request the same service in a wireless network. A base station obtains feedback on channel quality indications (CQIs) from a plurality of terminals, selects a transmission technique that satisfies desired service quality based on the CQIs, and transmits data to the terminals included in a receiving group by using the selected transmission technique. The CQIs to be transmitted from the terminals in the receiving group to the base station are transmitted through a previously allocated common CQI feedback channel. In the present invention, in order to reduce a CQI feedback channel capacity, the base station does not allocate a common CQI feedback channel with respect to each reception terminal and allocates radio resources according to CQI levels.

Abstract: Provided is a transmitter for transmitting an orthogonal frequency division multiplexing (OFDM) signal using multiple antennas, including: a subgroup generator to divide data symbols of a frequency domain into a plurality of subgroups; an inverse fast Fourier transform (IFFT) unit to perform an IFFT with respect to each of the subgroups so as to generate partial signals of a time domain corresponding to the plurality of subgroups, respectively; a candidate OFDM signal generator to generate at least two candidate OFDM signals using a combination of the partial signals so that each of the partial signals is transmitted to one of transmit antennas; and a selector to select one of the at least two candidate OFDM signals.

Abstract: A method and apparatus for adaptively transmitting the same data, i.e., multicast/broadcast data, according to channel quality to a receiving group including one or more terminals that request the same service in a wireless network. A base station obtains feedback on channel quality indications (CQIs) from a plurality of terminals, selects a transmission technique that satisfies desired service quality based on the COIs, and transmits data to the terminals included in a receiving group by using the selected transmission technique. The CQIs to be transmitted from the terminals in the receiving group to the base station are transmitted through a previously allocated common CQI feedback channel. In the present invention, in order to reduce a CQI feedback channel capacity, the base station does not allocate a common CQI feedback channel with respect to each reception terminal and allocates radio resources according to CQI levels.