AU Journal of Technology: Vol. 13, No. 4 (April 2010)

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    Eight-channel transmultiplexer with binary matrix sequences
    The duals of finite impulse response filters constructed of binary matrix sequences are used to design an eight-channel transmultiplexer. The binary matrix sequences of analysis and synthesis filters are obtained from corresponding complementary sequences which satisfy the conditions for perfect reconstruction. The distorions of eight transmultiplexed images in the presence of channel noise are studied for the case of a simulated transmission over a Digital Video Broadcasting-Satellite-Second Generation (DVB-S2) system.
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    Topology control for long distance transmission in multihop ad hoc networks
    This contribution is concerned with the performance evaluation of topology control algorithms for indoor ad hoc networks in multi-storey buildings. Several proposed topology control algorithms based on discrete sets are compared. The topology control algorithms operate with wireless links having variable transmission rates according to existing wireless communication standards. The maximum number of routing steps is limited to 15 hops. Computational experiments with a queuing analyzer for open networks are performed to extimate the connectivity between distant nodes in the network located at different vertical levels. The tradeoff between connectivity and delay-throughput is studied assuming that the algorithms are constrained to the selection of only five links by each node.
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    Decoding acceleration of low-density parity-check codes for mobile wirelessMAN
    The low-density parity-check (LDPC) codes have a relatively simple algorithm for error correction. The best performance of such codes is demonstrated for large frame sizes and a substantial number of iterations. The decoding delay depends on the number of iterations being performed with the received noisy data in order to obtain the best estimate to the transmitted data. A modification of the standard LDPC decoding algorithm is proposed, which is based on a statistical comparison of true and False convergence of an attempted decoding acceleration with the use of the Epsilon algorithm for convergence acceleration of the series of decoding iterations for the individual bits in each transmitted frame. Using the LDPC codec for Mobile WirelessMAN as an illustration, it is shown that the True convergence dominates over the False convergence which follows to a better bit error rate (BER) performance as compared to the standard (plain) scheme for a given number of iterations.