In this paper, we investigate the resource allocation for multi-user orthogonal frequency division multiple access (OFDMA) power line communication (PLC) systems, which satisfy both the total average transmit power constrained by PLC networks and the required interference limitations. First, we propose an optimal resource allocation scheme, with respect to joint consideration of the subcarrier and power constraint to maximize the throughput of the PLC system. Then, we divide the intractable problem into two individual subproblems to decrease the computational burden, which can avoid proceeding the mixed integer nonlinear programming (MINLP) problem. The proposed resource allocation scheme can ensure the optimality and efficiency of the system with rigorous proofs. The simulation results show that our proposed resource allocation scheme for the PLC system outperforms other algorithms, and is efficient with acceptable complexity.

Low-density parity-check (LDPC) codes can be applied in a lot of different scenarios such as video broadcasting and satellite communications. LDPC codes are commonly decoded by an iterative algorithm called belief propagation (BP) over the corresponding Tanner graph. The original BP updates all the variable-nodes simultaneously, followed by all the check-nodes simultaneously as well. We propose a sequential scheduling algorithm based on weighted bit-flipping (WBF) algorithm for the sake of improving the convergence speed. Notoriously, WBF is a low-complexity and simple algorithm. We combine it with BP to obtain advantages of these two algorithms. Flipping function used in WBF is borrowed to determine the priority of scheduling. Simulation results show that it can provide a good tradeoff between FER performance and computation complexity for short-length LDPC codes.