Complexity reduction method with low granularity block selection for TFI-MUDiv/OFDMA

In wireless communication systems, orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) achieve a high data rate and a high quality as multimedia services. In OFDM systems, large pilot symbols are required to obtain an accurate channel state information (CSI). To reduce this problem, a time frequency interferometry (TFI) for OFDM has been proposed. In a wireless network, the transmitted signal of each user has independent channel fluctuation characteristics. By using such characteristic, a multiuser diversity (MUDiv) for OFDMA has been proposed. The conventional MUDiv/OFDMA is considered the block selection. The block selection is based on the estimation of the SNR for the subcarrier block and chooses the strong subcarrier block. For the block of small number of subcarriers, the system achieves a diversity gain, but a complexity is large. In this paper, we propose the novel selection method based on the low granularity block to reduce the complexity for a MUDiv/OFDMA.