Patent ID: 7944809

Claim:
A method of controlling data transmission mode in an orthogonal frequency division multiple access (OFDMA) wireless relay system, the method comprising: dividing all frequency bands of an OFDM signal into a frequency band group including at least one subcarrier band; estimating a plurality of channels of wireless links which respectively link a base station (BS), at least one relay station (RS), and a mobile station (MS) with respect to the at least one subcarrier band; selecting any one of a plurality of data transmission modes based on a feature of the estimated plurality of channels of wireless links with respect to the frequency band group; and applying the selected data transmission mode to all of the at least one subcarrier bands in the frequency band group to transmit data, wherein the plurality of data transmission modes comprises at least one of: a first mode, a second mode, and a third mode, the first mode directly transmitting all data from the BS to the MS, the second mode transmitting the all data from the BS to the at least one RS, and forwarding the all data from the at least one RS to the MS, and the third mode transmitting a predetermined ratio of a first partial data of the all data from the BS to the MS, transmitting a second partial data of a remaining portion of the all data from the BS to the at least one RS, and forwarding the second partial data from the RS to the MS.