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In this paper, we propose reliability adjustment weighted bit-flipping (RA-WBF) decoding algorithm for low density parity-check (LDPC) codes. By adjusting the reliability of received symbols during iterative decoding, the proposed algorithm can offer better tradeoff between performance, convergence speed and computational complexity. Furthermore, this improvement can easily be extended to other variations of weighted bit-flipping decoding algorithm and obtain noticeable improvement in error performance. Simulation results are shown to verify our conclusions.

Aiming at the optimization algorithm, weak filled function method is proposed and which with simple form is constructed. The restriction of this method is weaker than the known filled function method, thus it is easier to construct function and solve algorithm. The weak filled function method is feasible through the theoretical analysis, and the global minimum of simulation example can be obtained in its interval. The results indicate that weak filled function method is an effective method.

UWB (Ultra-Wideband, UWB) is a short-range wireless transmission technology. For its high speed, low power, low complexity and low power spectral density, UWB is considered as the most important one of future wireless communications development directions. This paper focuses on the synchronization and channel parameters in UWB, and proposes the efficient closed-form estimation. In this paper, it is studied that the Hankel Matrix is constructed with the optimal number of columns in order to obtain the minimum element redundancy rate. Finally, the corresponding algorithm is designed, which not only can bring about the closed-form estimation, but also can greatly reduce the computation.