ML Detection with Successive Group Interference Cancellation for Interleaved OFDMA Uplink

To mitigate the interference caused by multiple carrier frequency offsets (CFO) of distributed users, a maximum likelihood (ML) detection with group-wise successive interference cancellation (GSIC) is proposed for interleaved Orthogonal Frequency Division Multiplexing Access (OFDMA) uplink. By exploiting the interference characteristics and the finite alphabet property of transmitted symbols, the proposed scheme first extracts the block diagonal of the frequency domain channel matrix and then employs ML detection via sphere decoding in each block. The decisions obtained from the detected blocks are used to mitigate the interference to the residual blocks. Numerical results show that the proposed scheme outperforms both the minimum mean square error (MMSE) detection and parallel interference cancellation (PIC) with affordable computational complexity.