Recently, orthogonal frequency division multiplexing (OFDM) has been adopted as the standard of the next generation mobile networks. We proposed the several transmission techniques in the patents. OFDM allows only one user on the channel at any given time. To accommodate multiple users, orthogonal frequency division multiple access (OFDMA) has been proposed. In the conventional 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.
Keywords: Low complexity, multiuser diversity, OFDMA, subcarrier selection, orthogonal frequency division multiple access, Communication system, data transmission, broadband wireless access systems, wireless communications, distributed antenna systems, OFDM wireless networks, MIMO-OFDMA systems, DVB-T receivers