Phakphisut, Watid

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Phakphisut, Watid
Alternative Name
Phakphisut, W.
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Email
watid.ph@kmitl.ac.th

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    Item type:Publication,
    Construction of punctured polar codes based on genetic algorithm
    (2021-05-19)
    Mueadkhunthod, Krittiyaporn
    ;
    Min Myint, Lin Min
    ;
    Supnithi, Pornchai
    ;
    Phakphisut, Watid
    In this work, we propose a new construction of punctured polar codes, which provides a good error-correcting performance at arbitrary code lengths and code rates. We exploit the density evolution to evaluate the error probability of punctured polar codes. Then, the puncturing pattern and frozen bit positions are selected by genetic algorithm to construct a punctured polar code with low error probability. The results show that the proposed technique provides superior block error rate performance than the quasi-uniform puncturing technique at a high code rate. At a low code rate, the proposed technique can show the better performance than the shortening technique.
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    Design of partition decoding for polar codes in 5G new radio
    (2020-10-08)
    Wongsa, Anusorn
    ;
    Phakphisut, Watid
    ;
    Min Myint, Lin Min
    ;
    Supnithi, Pornchai
    In this work, we consider partition decoding to diminish the required memory of polar codes in 5G new radio. We show that the suitable design of partition decoding for downlink and uplink control channels may differ. Moreover, the partitioning technique can reduce the computation complexity of polar decoder by limiting the number of codewords passed between partitions. We then propose to use the parity bits of interleaved CRC codes to select the codewords passed between partitions. The parity bits can help the partition decoding of which the codewords are verified. The simulation results show that the parity bits can improve the performance of partition decoding of polar codes in the downlink control channel of 5G new radio.
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    EXIT Chart Analysis of Protograph-based LDPC Codes for Unequal Power Two-User Gaussian Multiple Access Channel
    (2020-07-01)
    Khittiwitchayakul, Sirawit
    ;
    Phakphisut, Watid
    ;
    Supnithi, Pornchai
    ;
    Min Myint, Lin Min
    In this work, we analyze the theoretical performances of protograph-based LDPC codes for unequal power two-user Gaussian multiple access channel (GMAC) by using Extrinsic information transfer (EXIT) chart. We show that the decoding performances of LDPC codes for two-users are improved significantly when the transmitted power of user increases. Moreover, we present the design of protograph structures of the LDPC codes for unequal power two-user GMAC by using the differential evolution (DE). The results show that the designed LDPC codes outperform the traditional LDPC codes.
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    Construction of LSTM model for total electron content (TEC) prediction in Thailand
    (2021-05-19)
    Chimsuwan, Pathorn
    ;
    Supnithi, Pornchai
    ;
    Phakphisut, Watid
    ;
    Min Myint, Lin Min
    Total electron content (TEC) is an important parameter often used to explain the ionosphere characteristics and disturbances. Severe local disturbance often originates in the equatorial region then expand to low- and mid-latitude regions. Vertical TEC (VTEC as well as slant TEC (STEC) modeling's and predictions attract attention from researchers worldwide since they are essential for characterization and warning to users. Therefore, in this work, we design a local VTEC prediction model based on the Long-Short Term Memory (LSTM) Neural Network by using the GPS data from 12 stations in Thailand. The results show that the root mean square error (RMSE) of LSTM loopback 24 together with the 120 hidden layers from all stations in 2008-2016 is the best model. The RMSE of the proposed model from the actual VTEC reach about 3.26 TECu, less than that from the IRI 2016 model at 6.5 TECu. In addition, the R-square values of the proposed model and the IRI 2016 model reach 78.33% and 63.7892%, respectively, during storm and quiet periods in 2020. The designed LSTM model is a promising method to predict VTEC in this region.